drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/pm_domain.h>
  24 #include <linux/property.h>
  25 #include <linux/export.h>
  26 #include <linux/sched/rt.h>
  27 #include <uapi/linux/sched/types.h>
  28 #include <linux/delay.h>
  29 #include <linux/kthread.h>
  30 #include <linux/ioport.h>
  31 #include <linux/acpi.h>
  32 #include <linux/highmem.h>
  33 #include <linux/idr.h>
  34 #include <linux/platform_data/x86/apple.h>
  35
  36 #define CREATE_TRACE_POINTS
  37 #include <trace/events/spi.h>
  38
  39 #include "internals.h"
  40
  41 static DEFINE_IDR(spi_master_idr);
  42
  43 static void spidev_release(struct device *dev)
  44 {
  45         struct spi_device       *spi = to_spi_device(dev);
  46
  47         /* spi controllers may cleanup for released devices */
  48         if (spi->controller->cleanup)
  49                 spi->controller->cleanup(spi);
  50
  51         spi_controller_put(spi->controller);
  52         kfree(spi->driver_override);
  53         kfree(spi);
  54 }
  55
  56 static ssize_t
  57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  58 {
  59         const struct spi_device *spi = to_spi_device(dev);
  60         int len;
  61
  62         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  63         if (len != -ENODEV)
  64                 return len;
  65
  66         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  67 }
  68 static DEVICE_ATTR_RO(modalias);
  69
  70 static ssize_t driver_override_store(struct device *dev,
  71                                      struct device_attribute *a,
  72                                      const char *buf, size_t count)
  73 {
  74         struct spi_device *spi = to_spi_device(dev);
  75         const char *end = memchr(buf, '\n', count);
  76         const size_t len = end ? end - buf : count;
  77         const char *driver_override, *old;
  78
  79         /* We need to keep extra room for a newline when displaying value */
  80         if (len >= (PAGE_SIZE - 1))
  81                 return -EINVAL;
  82
  83         driver_override = kstrndup(buf, len, GFP_KERNEL);
  84         if (!driver_override)
  85                 return -ENOMEM;
  86
  87         device_lock(dev);
  88         old = spi->driver_override;
  89         if (len) {
  90                 spi->driver_override = driver_override;
  91         } else {
  92                 /* Emptry string, disable driver override */
  93                 spi->driver_override = NULL;
  94                 kfree(driver_override);
  95         }
  96         device_unlock(dev);
  97         kfree(old);
  98
  99         return count;
 100 }
 101
 102 static ssize_t driver_override_show(struct device *dev,
 103                                     struct device_attribute *a, char *buf)
 104 {
 105         const struct spi_device *spi = to_spi_device(dev);
 106         ssize_t len;
 107
 108         device_lock(dev);
 109         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 110         device_unlock(dev);
 111         return len;
 112 }
 113 static DEVICE_ATTR_RW(driver_override);
 114
 115 #define SPI_STATISTICS_ATTRS(field, file)                               \
 116 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 117                                              struct device_attribute *attr, \
 118                                              char *buf)                 \
 119 {                                                                       \
 120         struct spi_controller *ctlr = container_of(dev,                 \
 121                                          struct spi_controller, dev);   \
 122         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 123 }                                                                       \
 124 static struct device_attribute dev_attr_spi_controller_##field = {      \
 125         .attr = { .name = file, .mode = 0444 },                         \
 126         .show = spi_controller_##field##_show,                          \
 127 };                                                                      \
 128 static ssize_t spi_device_##field##_show(struct device *dev,            \
 129                                          struct device_attribute *attr, \
 130                                         char *buf)                      \
 131 {                                                                       \
 132         struct spi_device *spi = to_spi_device(dev);                    \
 133         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 134 }                                                                       \
 135 static struct device_attribute dev_attr_spi_device_##field = {          \
 136         .attr = { .name = file, .mode = 0444 },                         \
 137         .show = spi_device_##field##_show,                              \
 138 }
 139
 140 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 141 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 142                                             char *buf)                  \
 143 {                                                                       \
 144         unsigned long flags;                                            \
 145         ssize_t len;                                                    \
 146         spin_lock_irqsave(&stat->lock, flags);                          \
 147         len = sprintf(buf, format_string, stat->field);                 \
 148         spin_unlock_irqrestore(&stat->lock, flags);                     \
 149         return len;                                                     \
 150 }                                                                       \
 151 SPI_STATISTICS_ATTRS(name, file)
 152
 153 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 154         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 155                                  field, format_string)
 156
 157 SPI_STATISTICS_SHOW(messages, "%lu");
 158 SPI_STATISTICS_SHOW(transfers, "%lu");
 159 SPI_STATISTICS_SHOW(errors, "%lu");
 160 SPI_STATISTICS_SHOW(timedout, "%lu");
 161
 162 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 163 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 164 SPI_STATISTICS_SHOW(spi_async, "%lu");
 165
 166 SPI_STATISTICS_SHOW(bytes, "%llu");
 167 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 168 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 169
 170 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 171         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 172                                  "transfer_bytes_histo_" number,        \
 173                                  transfer_bytes_histo[index],  "%lu")
 174 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 175 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 176 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 191
 192 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 193
 194 static struct attribute *spi_dev_attrs[] = {
 195         &dev_attr_modalias.attr,
 196         &dev_attr_driver_override.attr,
 197         NULL,
 198 };
 199
 200 static const struct attribute_group spi_dev_group = {
 201         .attrs  = spi_dev_attrs,
 202 };
 203
 204 static struct attribute *spi_device_statistics_attrs[] = {
 205         &dev_attr_spi_device_messages.attr,
 206         &dev_attr_spi_device_transfers.attr,
 207         &dev_attr_spi_device_errors.attr,
 208         &dev_attr_spi_device_timedout.attr,
 209         &dev_attr_spi_device_spi_sync.attr,
 210         &dev_attr_spi_device_spi_sync_immediate.attr,
 211         &dev_attr_spi_device_spi_async.attr,
 212         &dev_attr_spi_device_bytes.attr,
 213         &dev_attr_spi_device_bytes_rx.attr,
 214         &dev_attr_spi_device_bytes_tx.attr,
 215         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 216         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 217         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 231         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 232         &dev_attr_spi_device_transfers_split_maxsize.attr,
 233         NULL,
 234 };
 235
 236 static const struct attribute_group spi_device_statistics_group = {
 237         .name  = "statistics",
 238         .attrs  = spi_device_statistics_attrs,
 239 };
 240
 241 static const struct attribute_group *spi_dev_groups[] = {
 242         &spi_dev_group,
 243         &spi_device_statistics_group,
 244         NULL,
 245 };
 246
 247 static struct attribute *spi_controller_statistics_attrs[] = {
 248         &dev_attr_spi_controller_messages.attr,
 249         &dev_attr_spi_controller_transfers.attr,
 250         &dev_attr_spi_controller_errors.attr,
 251         &dev_attr_spi_controller_timedout.attr,
 252         &dev_attr_spi_controller_spi_sync.attr,
 253         &dev_attr_spi_controller_spi_sync_immediate.attr,
 254         &dev_attr_spi_controller_spi_async.attr,
 255         &dev_attr_spi_controller_bytes.attr,
 256         &dev_attr_spi_controller_bytes_rx.attr,
 257         &dev_attr_spi_controller_bytes_tx.attr,
 258         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 259         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 260         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 274         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 275         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 276         NULL,
 277 };
 278
 279 static const struct attribute_group spi_controller_statistics_group = {
 280         .name  = "statistics",
 281         .attrs  = spi_controller_statistics_attrs,
 282 };
 283
 284 static const struct attribute_group *spi_master_groups[] = {
 285         &spi_controller_statistics_group,
 286         NULL,
 287 };
 288
 289 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 290                                        struct spi_transfer *xfer,
 291                                        struct spi_controller *ctlr)
 292 {
 293         unsigned long flags;
 294         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 295
 296         if (l2len < 0)
 297                 l2len = 0;
 298
 299         spin_lock_irqsave(&stats->lock, flags);
 300
 301         stats->transfers++;
 302         stats->transfer_bytes_histo[l2len]++;
 303
 304         stats->bytes += xfer->len;
 305         if ((xfer->tx_buf) &&
 306             (xfer->tx_buf != ctlr->dummy_tx))
 307                 stats->bytes_tx += xfer->len;
 308         if ((xfer->rx_buf) &&
 309             (xfer->rx_buf != ctlr->dummy_rx))
 310                 stats->bytes_rx += xfer->len;
 311
 312         spin_unlock_irqrestore(&stats->lock, flags);
 313 }
 314 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 315
 316 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 317  * and the sysfs version makes coldplug work too.
 318  */
 319
 320 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 321                                                 const struct spi_device *sdev)
 322 {
 323         while (id->name[0]) {
 324                 if (!strcmp(sdev->modalias, id->name))
 325                         return id;
 326                 id++;
 327         }
 328         return NULL;
 329 }
 330
 331 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 332 {
 333         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 334
 335         return spi_match_id(sdrv->id_table, sdev);
 336 }
 337 EXPORT_SYMBOL_GPL(spi_get_device_id);
 338
 339 static int spi_match_device(struct device *dev, struct device_driver *drv)
 340 {
 341         const struct spi_device *spi = to_spi_device(dev);
 342         const struct spi_driver *sdrv = to_spi_driver(drv);
 343
 344         /* Check override first, and if set, only use the named driver */
 345         if (spi->driver_override)
 346                 return strcmp(spi->driver_override, drv->name) == 0;
 347
 348         /* Attempt an OF style match */
 349         if (of_driver_match_device(dev, drv))
 350                 return 1;
 351
 352         /* Then try ACPI */
 353         if (acpi_driver_match_device(dev, drv))
 354                 return 1;
 355
 356         if (sdrv->id_table)
 357                 return !!spi_match_id(sdrv->id_table, spi);
 358
 359         return strcmp(spi->modalias, drv->name) == 0;
 360 }
 361
 362 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 363 {
 364         const struct spi_device         *spi = to_spi_device(dev);
 365         int rc;
 366
 367         rc = acpi_device_uevent_modalias(dev, env);
 368         if (rc != -ENODEV)
 369                 return rc;
 370
 371         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 372 }
 373
 374 struct bus_type spi_bus_type = {
 375         .name           = "spi",
 376         .dev_groups     = spi_dev_groups,
 377         .match          = spi_match_device,
 378         .uevent         = spi_uevent,
 379 };
 380 EXPORT_SYMBOL_GPL(spi_bus_type);
 381
 382
 383 static int spi_drv_probe(struct device *dev)
 384 {
 385         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 386         struct spi_device               *spi = to_spi_device(dev);
 387         int ret;
 388
 389         ret = of_clk_set_defaults(dev->of_node, false);
 390         if (ret)
 391                 return ret;
 392
 393         if (dev->of_node) {
 394                 spi->irq = of_irq_get(dev->of_node, 0);
 395                 if (spi->irq == -EPROBE_DEFER)
 396                         return -EPROBE_DEFER;
 397                 if (spi->irq < 0)
 398                         spi->irq = 0;
 399         }
 400
 401         ret = dev_pm_domain_attach(dev, true);
 402         if (ret)
 403                 return ret;
 404
 405         ret = sdrv->probe(spi);
 406         if (ret)
 407                 dev_pm_domain_detach(dev, true);
 408
 409         return ret;
 410 }
 411
 412 static int spi_drv_remove(struct device *dev)
 413 {
 414         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 415         int ret;
 416
 417         ret = sdrv->remove(to_spi_device(dev));
 418         dev_pm_domain_detach(dev, true);
 419
 420         return ret;
 421 }
 422
 423 static void spi_drv_shutdown(struct device *dev)
 424 {
 425         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 426
 427         sdrv->shutdown(to_spi_device(dev));
 428 }
 429
 430 /**
 431  * __spi_register_driver - register a SPI driver
 432  * @owner: owner module of the driver to register
 433  * @sdrv: the driver to register
 434  * Context: can sleep
 435  *
 436  * Return: zero on success, else a negative error code.
 437  */
 438 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 439 {
 440         sdrv->driver.owner = owner;
 441         sdrv->driver.bus = &spi_bus_type;
 442         if (sdrv->probe)
 443                 sdrv->driver.probe = spi_drv_probe;
 444         if (sdrv->remove)
 445                 sdrv->driver.remove = spi_drv_remove;
 446         if (sdrv->shutdown)
 447                 sdrv->driver.shutdown = spi_drv_shutdown;
 448         return driver_register(&sdrv->driver);
 449 }
 450 EXPORT_SYMBOL_GPL(__spi_register_driver);
 451
 452 /*-------------------------------------------------------------------------*/
 453
 454 /* SPI devices should normally not be created by SPI device drivers; that
 455  * would make them board-specific.  Similarly with SPI controller drivers.
 456  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 457  * with other readonly (flashable) information about mainboard devices.
 458  */
 459
 460 struct boardinfo {
 461         struct list_head        list;
 462         struct spi_board_info   board_info;
 463 };
 464
 465 static LIST_HEAD(board_list);
 466 static LIST_HEAD(spi_controller_list);
 467
 468 /*
 469  * Used to protect add/del opertion for board_info list and
 470  * spi_controller list, and their matching process
 471  * also used to protect object of type struct idr
 472  */
 473 static DEFINE_MUTEX(board_lock);
 474
 475 /**
 476  * spi_alloc_device - Allocate a new SPI device
 477  * @ctlr: Controller to which device is connected
 478  * Context: can sleep
 479  *
 480  * Allows a driver to allocate and initialize a spi_device without
 481  * registering it immediately.  This allows a driver to directly
 482  * fill the spi_device with device parameters before calling
 483  * spi_add_device() on it.
 484  *
 485  * Caller is responsible to call spi_add_device() on the returned
 486  * spi_device structure to add it to the SPI controller.  If the caller
 487  * needs to discard the spi_device without adding it, then it should
 488  * call spi_dev_put() on it.
 489  *
 490  * Return: a pointer to the new device, or NULL.
 491  */
 492 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 493 {
 494         struct spi_device       *spi;
 495
 496         if (!spi_controller_get(ctlr))
 497                 return NULL;
 498
 499         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 500         if (!spi) {
 501                 spi_controller_put(ctlr);
 502                 return NULL;
 503         }
 504
 505         spi->master = spi->controller = ctlr;
 506         spi->dev.parent = &ctlr->dev;
 507         spi->dev.bus = &spi_bus_type;
 508         spi->dev.release = spidev_release;
 509         spi->cs_gpio = -ENOENT;
 510
 511         spin_lock_init(&spi->statistics.lock);
 512
 513         device_initialize(&spi->dev);
 514         return spi;
 515 }
 516 EXPORT_SYMBOL_GPL(spi_alloc_device);
 517
 518 static void spi_dev_set_name(struct spi_device *spi)
 519 {
 520         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 521
 522         if (adev) {
 523                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 524                 return;
 525         }
 526
 527         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 528                      spi->chip_select);
 529 }
 530
 531 static int spi_dev_check(struct device *dev, void *data)
 532 {
 533         struct spi_device *spi = to_spi_device(dev);
 534         struct spi_device *new_spi = data;
 535
 536         if (spi->controller == new_spi->controller &&
 537             spi->chip_select == new_spi->chip_select)
 538                 return -EBUSY;
 539         return 0;
 540 }
 541
 542 /**
 543  * spi_add_device - Add spi_device allocated with spi_alloc_device
 544  * @spi: spi_device to register
 545  *
 546  * Companion function to spi_alloc_device.  Devices allocated with
 547  * spi_alloc_device can be added onto the spi bus with this function.
 548  *
 549  * Return: 0 on success; negative errno on failure
 550  */
 551 int spi_add_device(struct spi_device *spi)
 552 {
 553         static DEFINE_MUTEX(spi_add_lock);
 554         struct spi_controller *ctlr = spi->controller;
 555         struct device *dev = ctlr->dev.parent;
 556         int status;
 557
 558         /* Chipselects are numbered 0..max; validate. */
 559         if (spi->chip_select >= ctlr->num_chipselect) {
 560                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 561                         ctlr->num_chipselect);
 562                 return -EINVAL;
 563         }
 564
 565         /* Set the bus ID string */
 566         spi_dev_set_name(spi);
 567
 568         /* We need to make sure there's no other device with this
 569          * chipselect **BEFORE** we call setup(), else we'll trash
 570          * its configuration.  Lock against concurrent add() calls.
 571          */
 572         mutex_lock(&spi_add_lock);
 573
 574         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 575         if (status) {
 576                 dev_err(dev, "chipselect %d already in use\n",
 577                                 spi->chip_select);
 578                 goto done;
 579         }
 580
 581         if (ctlr->cs_gpios)
 582                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 583
 584         /* Drivers may modify this initial i/o setup, but will
 585          * normally rely on the device being setup.  Devices
 586          * using SPI_CS_HIGH can't coexist well otherwise...
 587          */
 588         status = spi_setup(spi);
 589         if (status < 0) {
 590                 dev_err(dev, "can't setup %s, status %d\n",
 591                                 dev_name(&spi->dev), status);
 592                 goto done;
 593         }
 594
 595         /* Device may be bound to an active driver when this returns */
 596         status = device_add(&spi->dev);
 597         if (status < 0)
 598                 dev_err(dev, "can't add %s, status %d\n",
 599                                 dev_name(&spi->dev), status);
 600         else
 601                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 602
 603 done:
 604         mutex_unlock(&spi_add_lock);
 605         return status;
 606 }
 607 EXPORT_SYMBOL_GPL(spi_add_device);
 608
 609 /**
 610  * spi_new_device - instantiate one new SPI device
 611  * @ctlr: Controller to which device is connected
 612  * @chip: Describes the SPI device
 613  * Context: can sleep
 614  *
 615  * On typical mainboards, this is purely internal; and it's not needed
 616  * after board init creates the hard-wired devices.  Some development
 617  * platforms may not be able to use spi_register_board_info though, and
 618  * this is exported so that for example a USB or parport based adapter
 619  * driver could add devices (which it would learn about out-of-band).
 620  *
 621  * Return: the new device, or NULL.
 622  */
 623 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 624                                   struct spi_board_info *chip)
 625 {
 626         struct spi_device       *proxy;
 627         int                     status;
 628
 629         /* NOTE:  caller did any chip->bus_num checks necessary.
 630          *
 631          * Also, unless we change the return value convention to use
 632          * error-or-pointer (not NULL-or-pointer), troubleshootability
 633          * suggests syslogged diagnostics are best here (ugh).
 634          */
 635
 636         proxy = spi_alloc_device(ctlr);
 637         if (!proxy)
 638                 return NULL;
 639
 640         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 641
 642         proxy->chip_select = chip->chip_select;
 643         proxy->max_speed_hz = chip->max_speed_hz;
 644         proxy->mode = chip->mode;
 645         proxy->irq = chip->irq;
 646         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 647         proxy->dev.platform_data = (void *) chip->platform_data;
 648         proxy->controller_data = chip->controller_data;
 649         proxy->controller_state = NULL;
 650
 651         if (chip->properties) {
 652                 status = device_add_properties(&proxy->dev, chip->properties);
 653                 if (status) {
 654                         dev_err(&ctlr->dev,
 655                                 "failed to add properties to '%s': %d\n",
 656                                 chip->modalias, status);
 657                         goto err_dev_put;
 658                 }
 659         }
 660
 661         status = spi_add_device(proxy);
 662         if (status < 0)
 663                 goto err_remove_props;
 664
 665         return proxy;
 666
 667 err_remove_props:
 668         if (chip->properties)
 669                 device_remove_properties(&proxy->dev);
 670 err_dev_put:
 671         spi_dev_put(proxy);
 672         return NULL;
 673 }
 674 EXPORT_SYMBOL_GPL(spi_new_device);
 675
 676 /**
 677  * spi_unregister_device - unregister a single SPI device
 678  * @spi: spi_device to unregister
 679  *
 680  * Start making the passed SPI device vanish. Normally this would be handled
 681  * by spi_unregister_controller().
 682  */
 683 void spi_unregister_device(struct spi_device *spi)
 684 {
 685         if (!spi)
 686                 return;
 687
 688         if (spi->dev.of_node) {
 689                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 690                 of_node_put(spi->dev.of_node);
 691         }
 692         if (ACPI_COMPANION(&spi->dev))
 693                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 694         device_unregister(&spi->dev);
 695 }
 696 EXPORT_SYMBOL_GPL(spi_unregister_device);
 697
 698 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 699                                               struct spi_board_info *bi)
 700 {
 701         struct spi_device *dev;
 702
 703         if (ctlr->bus_num != bi->bus_num)
 704                 return;
 705
 706         dev = spi_new_device(ctlr, bi);
 707         if (!dev)
 708                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 709                         bi->modalias);
 710 }
 711
 712 /**
 713  * spi_register_board_info - register SPI devices for a given board
 714  * @info: array of chip descriptors
 715  * @n: how many descriptors are provided
 716  * Context: can sleep
 717  *
 718  * Board-specific early init code calls this (probably during arch_initcall)
 719  * with segments of the SPI device table.  Any device nodes are created later,
 720  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 721  * this table of devices forever, so that reloading a controller driver will
 722  * not make Linux forget about these hard-wired devices.
 723  *
 724  * Other code can also call this, e.g. a particular add-on board might provide
 725  * SPI devices through its expansion connector, so code initializing that board
 726  * would naturally declare its SPI devices.
 727  *
 728  * The board info passed can safely be __initdata ... but be careful of
 729  * any embedded pointers (platform_data, etc), they're copied as-is.
 730  * Device properties are deep-copied though.
 731  *
 732  * Return: zero on success, else a negative error code.
 733  */
 734 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 735 {
 736         struct boardinfo *bi;
 737         int i;
 738
 739         if (!n)
 740                 return 0;
 741
 742         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 743         if (!bi)
 744                 return -ENOMEM;
 745
 746         for (i = 0; i < n; i++, bi++, info++) {
 747                 struct spi_controller *ctlr;
 748
 749                 memcpy(&bi->board_info, info, sizeof(*info));
 750                 if (info->properties) {
 751                         bi->board_info.properties =
 752                                         property_entries_dup(info->properties);
 753                         if (IS_ERR(bi->board_info.properties))
 754                                 return PTR_ERR(bi->board_info.properties);
 755                 }
 756
 757                 mutex_lock(&board_lock);
 758                 list_add_tail(&bi->list, &board_list);
 759                 list_for_each_entry(ctlr, &spi_controller_list, list)
 760                         spi_match_controller_to_boardinfo(ctlr,
 761                                                           &bi->board_info);
 762                 mutex_unlock(&board_lock);
 763         }
 764
 765         return 0;
 766 }
 767
 768 /*-------------------------------------------------------------------------*/
 769
 770 static void spi_set_cs(struct spi_device *spi, bool enable)
 771 {
 772         if (spi->mode & SPI_CS_HIGH)
 773                 enable = !enable;
 774
 775         if (gpio_is_valid(spi->cs_gpio)) {
 776                 /* Honour the SPI_NO_CS flag */
 777                 if (!(spi->mode & SPI_NO_CS))
 778                         gpio_set_value(spi->cs_gpio, !enable);
 779                 /* Some SPI masters need both GPIO CS & slave_select */
 780                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 781                     spi->controller->set_cs)
 782                         spi->controller->set_cs(spi, !enable);
 783         } else if (spi->controller->set_cs) {
 784                 spi->controller->set_cs(spi, !enable);
 785         }
 786 }
 787
 788 #ifdef CONFIG_HAS_DMA
 789 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 790                 struct sg_table *sgt, void *buf, size_t len,
 791                 enum dma_data_direction dir)
 792 {
 793         const bool vmalloced_buf = is_vmalloc_addr(buf);
 794         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 795 #ifdef CONFIG_HIGHMEM
 796         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 797                                 (unsigned long)buf < (PKMAP_BASE +
 798                                         (LAST_PKMAP * PAGE_SIZE)));
 799 #else
 800         const bool kmap_buf = false;
 801 #endif
 802         int desc_len;
 803         int sgs;
 804         struct page *vm_page;
 805         struct scatterlist *sg;
 806         void *sg_buf;
 807         size_t min;
 808         int i, ret;
 809
 810         if (vmalloced_buf || kmap_buf) {
 811                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 812                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 813         } else if (virt_addr_valid(buf)) {
 814                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 815                 sgs = DIV_ROUND_UP(len, desc_len);
 816         } else {
 817                 return -EINVAL;
 818         }
 819
 820         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 821         if (ret != 0)
 822                 return ret;
 823
 824         sg = &sgt->sgl[0];
 825         for (i = 0; i < sgs; i++) {
 826
 827                 if (vmalloced_buf || kmap_buf) {
 828                         /*
 829                          * Next scatterlist entry size is the minimum between
 830                          * the desc_len and the remaining buffer length that
 831                          * fits in a page.
 832                          */
 833                         min = min_t(size_t, desc_len,
 834                                     min_t(size_t, len,
 835                                           PAGE_SIZE - offset_in_page(buf)));
 836                         if (vmalloced_buf)
 837                                 vm_page = vmalloc_to_page(buf);
 838                         else
 839                                 vm_page = kmap_to_page(buf);
 840                         if (!vm_page) {
 841                                 sg_free_table(sgt);
 842                                 return -ENOMEM;
 843                         }
 844                         sg_set_page(sg, vm_page,
 845                                     min, offset_in_page(buf));
 846                 } else {
 847                         min = min_t(size_t, len, desc_len);
 848                         sg_buf = buf;
 849                         sg_set_buf(sg, sg_buf, min);
 850                 }
 851
 852                 buf += min;
 853                 len -= min;
 854                 sg = sg_next(sg);
 855         }
 856
 857         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 858         if (!ret)
 859                 ret = -ENOMEM;
 860         if (ret < 0) {
 861                 sg_free_table(sgt);
 862                 return ret;
 863         }
 864
 865         sgt->nents = ret;
 866
 867         return 0;
 868 }
 869
 870 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 871                    struct sg_table *sgt, enum dma_data_direction dir)
 872 {
 873         if (sgt->orig_nents) {
 874                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 875                 sg_free_table(sgt);
 876         }
 877 }
 878
 879 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 880 {
 881         struct device *tx_dev, *rx_dev;
 882         struct spi_transfer *xfer;
 883         int ret;
 884
 885         if (!ctlr->can_dma)
 886                 return 0;
 887
 888         if (ctlr->dma_tx)
 889                 tx_dev = ctlr->dma_tx->device->dev;
 890         else
 891                 tx_dev = ctlr->dev.parent;
 892
 893         if (ctlr->dma_rx)
 894                 rx_dev = ctlr->dma_rx->device->dev;
 895         else
 896                 rx_dev = ctlr->dev.parent;
 897
 898         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 899                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 900                         continue;
 901
 902                 if (xfer->tx_buf != NULL) {
 903                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 904                                           (void *)xfer->tx_buf, xfer->len,
 905                                           DMA_TO_DEVICE);
 906                         if (ret != 0)
 907                                 return ret;
 908                 }
 909
 910                 if (xfer->rx_buf != NULL) {
 911                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 912                                           xfer->rx_buf, xfer->len,
 913                                           DMA_FROM_DEVICE);
 914                         if (ret != 0) {
 915                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 916                                               DMA_TO_DEVICE);
 917                                 return ret;
 918                         }
 919                 }
 920         }
 921
 922         ctlr->cur_msg_mapped = true;
 923
 924         return 0;
 925 }
 926
 927 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 928 {
 929         struct spi_transfer *xfer;
 930         struct device *tx_dev, *rx_dev;
 931
 932         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 933                 return 0;
 934
 935         if (ctlr->dma_tx)
 936                 tx_dev = ctlr->dma_tx->device->dev;
 937         else
 938                 tx_dev = ctlr->dev.parent;
 939
 940         if (ctlr->dma_rx)
 941                 rx_dev = ctlr->dma_rx->device->dev;
 942         else
 943                 rx_dev = ctlr->dev.parent;
 944
 945         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 946                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 947                         continue;
 948
 949                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 950                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 951         }
 952
 953         return 0;
 954 }
 955 #else /* !CONFIG_HAS_DMA */
 956 static inline int __spi_map_msg(struct spi_controller *ctlr,
 957                                 struct spi_message *msg)
 958 {
 959         return 0;
 960 }
 961
 962 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 963                                   struct spi_message *msg)
 964 {
 965         return 0;
 966 }
 967 #endif /* !CONFIG_HAS_DMA */
 968
 969 static inline int spi_unmap_msg(struct spi_controller *ctlr,
 970                                 struct spi_message *msg)
 971 {
 972         struct spi_transfer *xfer;
 973
 974         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 975                 /*
 976                  * Restore the original value of tx_buf or rx_buf if they are
 977                  * NULL.
 978                  */
 979                 if (xfer->tx_buf == ctlr->dummy_tx)
 980                         xfer->tx_buf = NULL;
 981                 if (xfer->rx_buf == ctlr->dummy_rx)
 982                         xfer->rx_buf = NULL;
 983         }
 984
 985         return __spi_unmap_msg(ctlr, msg);
 986 }
 987
 988 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 989 {
 990         struct spi_transfer *xfer;
 991         void *tmp;
 992         unsigned int max_tx, max_rx;
 993
 994         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
 995                 max_tx = 0;
 996                 max_rx = 0;
 997
 998                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 999                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1000                             !xfer->tx_buf)
1001                                 max_tx = max(xfer->len, max_tx);
1002                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1003                             !xfer->rx_buf)
1004                                 max_rx = max(xfer->len, max_rx);
1005                 }
1006
1007                 if (max_tx) {
1008                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1009                                        GFP_KERNEL | GFP_DMA);
1010                         if (!tmp)
1011                                 return -ENOMEM;
1012                         ctlr->dummy_tx = tmp;
1013                         memset(tmp, 0, max_tx);
1014                 }
1015
1016                 if (max_rx) {
1017                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1018                                        GFP_KERNEL | GFP_DMA);
1019                         if (!tmp)
1020                                 return -ENOMEM;
1021                         ctlr->dummy_rx = tmp;
1022                 }
1023
1024                 if (max_tx || max_rx) {
1025                         list_for_each_entry(xfer, &msg->transfers,
1026                                             transfer_list) {
1027                                 if (!xfer->tx_buf)
1028                                         xfer->tx_buf = ctlr->dummy_tx;
1029                                 if (!xfer->rx_buf)
1030                                         xfer->rx_buf = ctlr->dummy_rx;
1031                         }
1032                 }
1033         }
1034
1035         return __spi_map_msg(ctlr, msg);
1036 }
1037
1038 static int spi_transfer_wait(struct spi_controller *ctlr,
1039                              struct spi_message *msg,
1040                              struct spi_transfer *xfer)
1041 {
1042         struct spi_statistics *statm = &ctlr->statistics;
1043         struct spi_statistics *stats = &msg->spi->statistics;
1044         unsigned long long ms = 1;
1045
1046         if (spi_controller_is_slave(ctlr)) {
1047                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1048                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1049                         return -EINTR;
1050                 }
1051         } else {
1052                 ms = 8LL * 1000LL * xfer->len;
1053                 do_div(ms, xfer->speed_hz);
1054                 ms += ms + 200; /* some tolerance */
1055
1056                 if (ms > UINT_MAX)
1057                         ms = UINT_MAX;
1058
1059                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1060                                                  msecs_to_jiffies(ms));
1061
1062                 if (ms == 0) {
1063                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1064                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1065                         dev_err(&msg->spi->dev,
1066                                 "SPI transfer timed out\n");
1067                         return -ETIMEDOUT;
1068                 }
1069         }
1070
1071         return 0;
1072 }
1073
1074 /*
1075  * spi_transfer_one_message - Default implementation of transfer_one_message()
1076  *
1077  * This is a standard implementation of transfer_one_message() for
1078  * drivers which implement a transfer_one() operation.  It provides
1079  * standard handling of delays and chip select management.
1080  */
1081 static int spi_transfer_one_message(struct spi_controller *ctlr,
1082                                     struct spi_message *msg)
1083 {
1084         struct spi_transfer *xfer;
1085         bool keep_cs = false;
1086         int ret = 0;
1087         struct spi_statistics *statm = &ctlr->statistics;
1088         struct spi_statistics *stats = &msg->spi->statistics;
1089
1090         spi_set_cs(msg->spi, true);
1091
1092         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1093         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1094
1095         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1096                 trace_spi_transfer_start(msg, xfer);
1097
1098                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1099                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1100
1101                 if (xfer->tx_buf || xfer->rx_buf) {
1102                         reinit_completion(&ctlr->xfer_completion);
1103
1104                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1105                         if (ret < 0) {
1106                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1107                                                                errors);
1108                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1109                                                                errors);
1110                                 dev_err(&msg->spi->dev,
1111                                         "SPI transfer failed: %d\n", ret);
1112                                 goto out;
1113                         }
1114
1115                         if (ret > 0) {
1116                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1117                                 if (ret < 0)
1118                                         msg->status = ret;
1119                         }
1120                 } else {
1121                         if (xfer->len)
1122                                 dev_err(&msg->spi->dev,
1123                                         "Bufferless transfer has length %u\n",
1124                                         xfer->len);
1125                 }
1126
1127                 trace_spi_transfer_stop(msg, xfer);
1128
1129                 if (msg->status != -EINPROGRESS)
1130                         goto out;
1131
1132                 if (xfer->delay_usecs) {
1133                         u16 us = xfer->delay_usecs;
1134
1135                         if (us <= 10)
1136                                 udelay(us);
1137                         else
1138                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1139                 }
1140
1141                 if (xfer->cs_change) {
1142                         if (list_is_last(&xfer->transfer_list,
1143                                          &msg->transfers)) {
1144                                 keep_cs = true;
1145                         } else {
1146                                 spi_set_cs(msg->spi, false);
1147                                 udelay(10);
1148                                 spi_set_cs(msg->spi, true);
1149                         }
1150                 }
1151
1152                 msg->actual_length += xfer->len;
1153         }
1154
1155 out:
1156         if (ret != 0 || !keep_cs)
1157                 spi_set_cs(msg->spi, false);
1158
1159         if (msg->status == -EINPROGRESS)
1160                 msg->status = ret;
1161
1162         if (msg->status && ctlr->handle_err)
1163                 ctlr->handle_err(ctlr, msg);
1164
1165         spi_res_release(ctlr, msg);
1166
1167         spi_finalize_current_message(ctlr);
1168
1169         return ret;
1170 }
1171
1172 /**
1173  * spi_finalize_current_transfer - report completion of a transfer
1174  * @ctlr: the controller reporting completion
1175  *
1176  * Called by SPI drivers using the core transfer_one_message()
1177  * implementation to notify it that the current interrupt driven
1178  * transfer has finished and the next one may be scheduled.
1179  */
1180 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1181 {
1182         complete(&ctlr->xfer_completion);
1183 }
1184 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1185
1186 /**
1187  * __spi_pump_messages - function which processes spi message queue
1188  * @ctlr: controller to process queue for
1189  * @in_kthread: true if we are in the context of the message pump thread
1190  *
1191  * This function checks if there is any spi message in the queue that
1192  * needs processing and if so call out to the driver to initialize hardware
1193  * and transfer each message.
1194  *
1195  * Note that it is called both from the kthread itself and also from
1196  * inside spi_sync(); the queue extraction handling at the top of the
1197  * function should deal with this safely.
1198  */
1199 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1200 {
1201         unsigned long flags;
1202         bool was_busy = false;
1203         int ret;
1204
1205         /* Lock queue */
1206         spin_lock_irqsave(&ctlr->queue_lock, flags);
1207
1208         /* Make sure we are not already running a message */
1209         if (ctlr->cur_msg) {
1210                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1211                 return;
1212         }
1213
1214         /* If another context is idling the device then defer */
1215         if (ctlr->idling) {
1216                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1217                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1218                 return;
1219         }
1220
1221         /* Check if the queue is idle */
1222         if (list_empty(&ctlr->queue) || !ctlr->running) {
1223                 if (!ctlr->busy) {
1224                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1225                         return;
1226                 }
1227
1228                 /* Only do teardown in the thread */
1229                 if (!in_kthread) {
1230                         kthread_queue_work(&ctlr->kworker,
1231                                            &ctlr->pump_messages);
1232                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1233                         return;
1234                 }
1235
1236                 ctlr->busy = false;
1237                 ctlr->idling = true;
1238                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1239
1240                 kfree(ctlr->dummy_rx);
1241                 ctlr->dummy_rx = NULL;
1242                 kfree(ctlr->dummy_tx);
1243                 ctlr->dummy_tx = NULL;
1244                 if (ctlr->unprepare_transfer_hardware &&
1245                     ctlr->unprepare_transfer_hardware(ctlr))
1246                         dev_err(&ctlr->dev,
1247                                 "failed to unprepare transfer hardware\n");
1248                 if (ctlr->auto_runtime_pm) {
1249                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1250                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1251                 }
1252                 trace_spi_controller_idle(ctlr);
1253
1254                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1255                 ctlr->idling = false;
1256                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1257                 return;
1258         }
1259
1260         /* Extract head of queue */
1261         ctlr->cur_msg =
1262                 list_first_entry(&ctlr->queue, struct spi_message, queue);
1263
1264         list_del_init(&ctlr->cur_msg->queue);
1265         if (ctlr->busy)
1266                 was_busy = true;
1267         else
1268                 ctlr->busy = true;
1269         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1270
1271         mutex_lock(&ctlr->io_mutex);
1272
1273         if (!was_busy && ctlr->auto_runtime_pm) {
1274                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1275                 if (ret < 0) {
1276                         pm_runtime_put_noidle(ctlr->dev.parent);
1277                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1278                                 ret);
1279                         mutex_unlock(&ctlr->io_mutex);
1280                         return;
1281                 }
1282         }
1283
1284         if (!was_busy)
1285                 trace_spi_controller_busy(ctlr);
1286
1287         if (!was_busy && ctlr->prepare_transfer_hardware) {
1288                 ret = ctlr->prepare_transfer_hardware(ctlr);
1289                 if (ret) {
1290                         dev_err(&ctlr->dev,
1291                                 "failed to prepare transfer hardware\n");
1292
1293                         if (ctlr->auto_runtime_pm)
1294                                 pm_runtime_put(ctlr->dev.parent);
1295                         mutex_unlock(&ctlr->io_mutex);
1296                         return;
1297                 }
1298         }
1299
1300         trace_spi_message_start(ctlr->cur_msg);
1301
1302         if (ctlr->prepare_message) {
1303                 ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
1304                 if (ret) {
1305                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1306                                 ret);
1307                         ctlr->cur_msg->status = ret;
1308                         spi_finalize_current_message(ctlr);
1309                         goto out;
1310                 }
1311                 ctlr->cur_msg_prepared = true;
1312         }
1313
1314         ret = spi_map_msg(ctlr, ctlr->cur_msg);
1315         if (ret) {
1316                 ctlr->cur_msg->status = ret;
1317                 spi_finalize_current_message(ctlr);
1318                 goto out;
1319         }
1320
1321         ret = ctlr->transfer_one_message(ctlr, ctlr->cur_msg);
1322         if (ret) {
1323                 dev_err(&ctlr->dev,
1324                         "failed to transfer one message from queue\n");
1325                 goto out;
1326         }
1327
1328 out:
1329         mutex_unlock(&ctlr->io_mutex);
1330
1331         /* Prod the scheduler in case transfer_one() was busy waiting */
1332         if (!ret)
1333                 cond_resched();
1334 }
1335
1336 /**
1337  * spi_pump_messages - kthread work function which processes spi message queue
1338  * @work: pointer to kthread work struct contained in the controller struct
1339  */
1340 static void spi_pump_messages(struct kthread_work *work)
1341 {
1342         struct spi_controller *ctlr =
1343                 container_of(work, struct spi_controller, pump_messages);
1344
1345         __spi_pump_messages(ctlr, true);
1346 }
1347
1348 static int spi_init_queue(struct spi_controller *ctlr)
1349 {
1350         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1351
1352         ctlr->running = false;
1353         ctlr->busy = false;
1354
1355         kthread_init_worker(&ctlr->kworker);
1356         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1357                                          "%s", dev_name(&ctlr->dev));
1358         if (IS_ERR(ctlr->kworker_task)) {
1359                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1360                 return PTR_ERR(ctlr->kworker_task);
1361         }
1362         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1363
1364         /*
1365          * Controller config will indicate if this controller should run the
1366          * message pump with high (realtime) priority to reduce the transfer
1367          * latency on the bus by minimising the delay between a transfer
1368          * request and the scheduling of the message pump thread. Without this
1369          * setting the message pump thread will remain at default priority.
1370          */
1371         if (ctlr->rt) {
1372                 dev_info(&ctlr->dev,
1373                         "will run message pump with realtime priority\n");
1374                 sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1375         }
1376
1377         return 0;
1378 }
1379
1380 /**
1381  * spi_get_next_queued_message() - called by driver to check for queued
1382  * messages
1383  * @ctlr: the controller to check for queued messages
1384  *
1385  * If there are more messages in the queue, the next message is returned from
1386  * this call.
1387  *
1388  * Return: the next message in the queue, else NULL if the queue is empty.
1389  */
1390 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1391 {
1392         struct spi_message *next;
1393         unsigned long flags;
1394
1395         /* get a pointer to the next message, if any */
1396         spin_lock_irqsave(&ctlr->queue_lock, flags);
1397         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1398                                         queue);
1399         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1400
1401         return next;
1402 }
1403 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1404
1405 /**
1406  * spi_finalize_current_message() - the current message is complete
1407  * @ctlr: the controller to return the message to
1408  *
1409  * Called by the driver to notify the core that the message in the front of the
1410  * queue is complete and can be removed from the queue.
1411  */
1412 void spi_finalize_current_message(struct spi_controller *ctlr)
1413 {
1414         struct spi_message *mesg;
1415         unsigned long flags;
1416         int ret;
1417
1418         spin_lock_irqsave(&ctlr->queue_lock, flags);
1419         mesg = ctlr->cur_msg;
1420         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1421
1422         spi_unmap_msg(ctlr, mesg);
1423
1424         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1425                 ret = ctlr->unprepare_message(ctlr, mesg);
1426                 if (ret) {
1427                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1428                                 ret);
1429                 }
1430         }
1431
1432         spin_lock_irqsave(&ctlr->queue_lock, flags);
1433         ctlr->cur_msg = NULL;
1434         ctlr->cur_msg_prepared = false;
1435         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1436         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1437
1438         trace_spi_message_done(mesg);
1439
1440         mesg->state = NULL;
1441         if (mesg->complete)
1442                 mesg->complete(mesg->context);
1443 }
1444 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1445
1446 static int spi_start_queue(struct spi_controller *ctlr)
1447 {
1448         unsigned long flags;
1449
1450         spin_lock_irqsave(&ctlr->queue_lock, flags);
1451
1452         if (ctlr->running || ctlr->busy) {
1453                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1454                 return -EBUSY;
1455         }
1456
1457         ctlr->running = true;
1458         ctlr->cur_msg = NULL;
1459         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1460
1461         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1462
1463         return 0;
1464 }
1465
1466 static int spi_stop_queue(struct spi_controller *ctlr)
1467 {
1468         unsigned long flags;
1469         unsigned limit = 500;
1470         int ret = 0;
1471
1472         spin_lock_irqsave(&ctlr->queue_lock, flags);
1473
1474         /*
1475          * This is a bit lame, but is optimized for the common execution path.
1476          * A wait_queue on the ctlr->busy could be used, but then the common
1477          * execution path (pump_messages) would be required to call wake_up or
1478          * friends on every SPI message. Do this instead.
1479          */
1480         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1481                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1482                 usleep_range(10000, 11000);
1483                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1484         }
1485
1486         if (!list_empty(&ctlr->queue) || ctlr->busy)
1487                 ret = -EBUSY;
1488         else
1489                 ctlr->running = false;
1490
1491         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1492
1493         if (ret) {
1494                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1495                 return ret;
1496         }
1497         return ret;
1498 }
1499
1500 static int spi_destroy_queue(struct spi_controller *ctlr)
1501 {
1502         int ret;
1503
1504         ret = spi_stop_queue(ctlr);
1505
1506         /*
1507          * kthread_flush_worker will block until all work is done.
1508          * If the reason that stop_queue timed out is that the work will never
1509          * finish, then it does no good to call flush/stop thread, so
1510          * return anyway.
1511          */
1512         if (ret) {
1513                 dev_err(&ctlr->dev, "problem destroying queue\n");
1514                 return ret;
1515         }
1516
1517         kthread_flush_worker(&ctlr->kworker);
1518         kthread_stop(ctlr->kworker_task);
1519
1520         return 0;
1521 }
1522
1523 static int __spi_queued_transfer(struct spi_device *spi,
1524                                  struct spi_message *msg,
1525                                  bool need_pump)
1526 {
1527         struct spi_controller *ctlr = spi->controller;
1528         unsigned long flags;
1529
1530         spin_lock_irqsave(&ctlr->queue_lock, flags);
1531
1532         if (!ctlr->running) {
1533                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1534                 return -ESHUTDOWN;
1535         }
1536         msg->actual_length = 0;
1537         msg->status = -EINPROGRESS;
1538
1539         list_add_tail(&msg->queue, &ctlr->queue);
1540         if (!ctlr->busy && need_pump)
1541                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1542
1543         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1544         return 0;
1545 }
1546
1547 /**
1548  * spi_queued_transfer - transfer function for queued transfers
1549  * @spi: spi device which is requesting transfer
1550  * @msg: spi message which is to handled is queued to driver queue
1551  *
1552  * Return: zero on success, else a negative error code.
1553  */
1554 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1555 {
1556         return __spi_queued_transfer(spi, msg, true);
1557 }
1558
1559 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1560 {
1561         int ret;
1562
1563         ctlr->transfer = spi_queued_transfer;
1564         if (!ctlr->transfer_one_message)
1565                 ctlr->transfer_one_message = spi_transfer_one_message;
1566
1567         /* Initialize and start queue */
1568         ret = spi_init_queue(ctlr);
1569         if (ret) {
1570                 dev_err(&ctlr->dev, "problem initializing queue\n");
1571                 goto err_init_queue;
1572         }
1573         ctlr->queued = true;
1574         ret = spi_start_queue(ctlr);
1575         if (ret) {
1576                 dev_err(&ctlr->dev, "problem starting queue\n");
1577                 goto err_start_queue;
1578         }
1579
1580         return 0;
1581
1582 err_start_queue:
1583         spi_destroy_queue(ctlr);
1584 err_init_queue:
1585         return ret;
1586 }
1587
1588 /**
1589  * spi_flush_queue - Send all pending messages in the queue from the callers'
1590  *                   context
1591  * @ctlr: controller to process queue for
1592  *
1593  * This should be used when one wants to ensure all pending messages have been
1594  * sent before doing something. Is used by the spi-mem code to make sure SPI
1595  * memory operations do not preempt regular SPI transfers that have been queued
1596  * before the spi-mem operation.
1597  */
1598 void spi_flush_queue(struct spi_controller *ctlr)
1599 {
1600         if (ctlr->transfer == spi_queued_transfer)
1601                 __spi_pump_messages(ctlr, false);
1602 }
1603
1604 /*-------------------------------------------------------------------------*/
1605
1606 #if defined(CONFIG_OF)
1607 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1608                            struct device_node *nc)
1609 {
1610         u32 value;
1611         int rc;
1612
1613         /* Mode (clock phase/polarity/etc.) */
1614         if (of_property_read_bool(nc, "spi-cpha"))
1615                 spi->mode |= SPI_CPHA;
1616         if (of_property_read_bool(nc, "spi-cpol"))
1617                 spi->mode |= SPI_CPOL;
1618         if (of_property_read_bool(nc, "spi-cs-high"))
1619                 spi->mode |= SPI_CS_HIGH;
1620         if (of_property_read_bool(nc, "spi-3wire"))
1621                 spi->mode |= SPI_3WIRE;
1622         if (of_property_read_bool(nc, "spi-lsb-first"))
1623                 spi->mode |= SPI_LSB_FIRST;
1624
1625         /* Device DUAL/QUAD mode */
1626         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1627                 switch (value) {
1628                 case 1:
1629                         break;
1630                 case 2:
1631                         spi->mode |= SPI_TX_DUAL;
1632                         break;
1633                 case 4:
1634                         spi->mode |= SPI_TX_QUAD;
1635                         break;
1636                 case 8:
1637                         spi->mode |= SPI_TX_OCTAL;
1638                         break;
1639                 default:
1640                         dev_warn(&ctlr->dev,
1641                                 "spi-tx-bus-width %d not supported\n",
1642                                 value);
1643                         break;
1644                 }
1645         }
1646
1647         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1648                 switch (value) {
1649                 case 1:
1650                         break;
1651                 case 2:
1652                         spi->mode |= SPI_RX_DUAL;
1653                         break;
1654                 case 4:
1655                         spi->mode |= SPI_RX_QUAD;
1656                         break;
1657                 case 8:
1658                         spi->mode |= SPI_RX_OCTAL;
1659                         break;
1660                 default:
1661                         dev_warn(&ctlr->dev,
1662                                 "spi-rx-bus-width %d not supported\n",
1663                                 value);
1664                         break;
1665                 }
1666         }
1667
1668         if (spi_controller_is_slave(ctlr)) {
1669                 if (!of_node_name_eq(nc, "slave")) {
1670                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1671                                 nc);
1672                         return -EINVAL;
1673                 }
1674                 return 0;
1675         }
1676
1677         /* Device address */
1678         rc = of_property_read_u32(nc, "reg", &value);
1679         if (rc) {
1680                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1681                         nc, rc);
1682                 return rc;
1683         }
1684         spi->chip_select = value;
1685
1686         /* Device speed */
1687         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1688         if (rc) {
1689                 dev_err(&ctlr->dev,
1690                         "%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1691                 return rc;
1692         }
1693         spi->max_speed_hz = value;
1694
1695         return 0;
1696 }
1697
1698 static struct spi_device *
1699 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1700 {
1701         struct spi_device *spi;
1702         int rc;
1703
1704         /* Alloc an spi_device */
1705         spi = spi_alloc_device(ctlr);
1706         if (!spi) {
1707                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1708                 rc = -ENOMEM;
1709                 goto err_out;
1710         }
1711
1712         /* Select device driver */
1713         rc = of_modalias_node(nc, spi->modalias,
1714                                 sizeof(spi->modalias));
1715         if (rc < 0) {
1716                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1717                 goto err_out;
1718         }
1719
1720         rc = of_spi_parse_dt(ctlr, spi, nc);
1721         if (rc)
1722                 goto err_out;
1723
1724         /* Store a pointer to the node in the device structure */
1725         of_node_get(nc);
1726         spi->dev.of_node = nc;
1727
1728         /* Register the new device */
1729         rc = spi_add_device(spi);
1730         if (rc) {
1731                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1732                 goto err_of_node_put;
1733         }
1734
1735         return spi;
1736
1737 err_of_node_put:
1738         of_node_put(nc);
1739 err_out:
1740         spi_dev_put(spi);
1741         return ERR_PTR(rc);
1742 }
1743
1744 /**
1745  * of_register_spi_devices() - Register child devices onto the SPI bus
1746  * @ctlr:       Pointer to spi_controller device
1747  *
1748  * Registers an spi_device for each child node of controller node which
1749  * represents a valid SPI slave.
1750  */
1751 static void of_register_spi_devices(struct spi_controller *ctlr)
1752 {
1753         struct spi_device *spi;
1754         struct device_node *nc;
1755
1756         if (!ctlr->dev.of_node)
1757                 return;
1758
1759         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1760                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1761                         continue;
1762                 spi = of_register_spi_device(ctlr, nc);
1763                 if (IS_ERR(spi)) {
1764                         dev_warn(&ctlr->dev,
1765                                  "Failed to create SPI device for %pOF\n", nc);
1766                         of_node_clear_flag(nc, OF_POPULATED);
1767                 }
1768         }
1769 }
1770 #else
1771 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1772 #endif
1773
1774 #ifdef CONFIG_ACPI
1775 static void acpi_spi_parse_apple_properties(struct spi_device *spi)
1776 {
1777         struct acpi_device *dev = ACPI_COMPANION(&spi->dev);
1778         const union acpi_object *obj;
1779
1780         if (!x86_apple_machine)
1781                 return;
1782
1783         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
1784             && obj->buffer.length >= 4)
1785                 spi->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
1786
1787         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
1788             && obj->buffer.length == 8)
1789                 spi->bits_per_word = *(u64 *)obj->buffer.pointer;
1790
1791         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
1792             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
1793                 spi->mode |= SPI_LSB_FIRST;
1794
1795         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
1796             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1797                 spi->mode |= SPI_CPOL;
1798
1799         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
1800             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1801                 spi->mode |= SPI_CPHA;
1802 }
1803
1804 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1805 {
1806         struct spi_device *spi = data;
1807         struct spi_controller *ctlr = spi->controller;
1808
1809         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1810                 struct acpi_resource_spi_serialbus *sb;
1811
1812                 sb = &ares->data.spi_serial_bus;
1813                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1814                         /*
1815                          * ACPI DeviceSelection numbering is handled by the
1816                          * host controller driver in Windows and can vary
1817                          * from driver to driver. In Linux we always expect
1818                          * 0 .. max - 1 so we need to ask the driver to
1819                          * translate between the two schemes.
1820                          */
1821                         if (ctlr->fw_translate_cs) {
1822                                 int cs = ctlr->fw_translate_cs(ctlr,
1823                                                 sb->device_selection);
1824                                 if (cs < 0)
1825                                         return cs;
1826                                 spi->chip_select = cs;
1827                         } else {
1828                                 spi->chip_select = sb->device_selection;
1829                         }
1830
1831                         spi->max_speed_hz = sb->connection_speed;
1832
1833                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1834                                 spi->mode |= SPI_CPHA;
1835                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1836                                 spi->mode |= SPI_CPOL;
1837                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1838                                 spi->mode |= SPI_CS_HIGH;
1839                 }
1840         } else if (spi->irq < 0) {
1841                 struct resource r;
1842
1843                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1844                         spi->irq = r.start;
1845         }
1846
1847         /* Always tell the ACPI core to skip this resource */
1848         return 1;
1849 }
1850
1851 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1852                                             struct acpi_device *adev)
1853 {
1854         struct list_head resource_list;
1855         struct spi_device *spi;
1856         int ret;
1857
1858         if (acpi_bus_get_status(adev) || !adev->status.present ||
1859             acpi_device_enumerated(adev))
1860                 return AE_OK;
1861
1862         spi = spi_alloc_device(ctlr);
1863         if (!spi) {
1864                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1865                         dev_name(&adev->dev));
1866                 return AE_NO_MEMORY;
1867         }
1868
1869         ACPI_COMPANION_SET(&spi->dev, adev);
1870         spi->irq = -1;
1871
1872         INIT_LIST_HEAD(&resource_list);
1873         ret = acpi_dev_get_resources(adev, &resource_list,
1874                                      acpi_spi_add_resource, spi);
1875         acpi_dev_free_resource_list(&resource_list);
1876
1877         acpi_spi_parse_apple_properties(spi);
1878
1879         if (ret < 0 || !spi->max_speed_hz) {
1880                 spi_dev_put(spi);
1881                 return AE_OK;
1882         }
1883
1884         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1885                           sizeof(spi->modalias));
1886
1887         if (spi->irq < 0)
1888                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1889
1890         acpi_device_set_enumerated(adev);
1891
1892         adev->power.flags.ignore_parent = true;
1893         if (spi_add_device(spi)) {
1894                 adev->power.flags.ignore_parent = false;
1895                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1896                         dev_name(&adev->dev));
1897                 spi_dev_put(spi);
1898         }
1899
1900         return AE_OK;
1901 }
1902
1903 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1904                                        void *data, void **return_value)
1905 {
1906         struct spi_controller *ctlr = data;
1907         struct acpi_device *adev;
1908
1909         if (acpi_bus_get_device(handle, &adev))
1910                 return AE_OK;
1911
1912         return acpi_register_spi_device(ctlr, adev);
1913 }
1914
1915 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1916 {
1917         acpi_status status;
1918         acpi_handle handle;
1919
1920         handle = ACPI_HANDLE(ctlr->dev.parent);
1921         if (!handle)
1922                 return;
1923
1924         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1925                                      acpi_spi_add_device, NULL, ctlr, NULL);
1926         if (ACPI_FAILURE(status))
1927                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
1928 }
1929 #else
1930 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
1931 #endif /* CONFIG_ACPI */
1932
1933 static void spi_controller_release(struct device *dev)
1934 {
1935         struct spi_controller *ctlr;
1936
1937         ctlr = container_of(dev, struct spi_controller, dev);
1938         kfree(ctlr);
1939 }
1940
1941 static struct class spi_master_class = {
1942         .name           = "spi_master",
1943         .owner          = THIS_MODULE,
1944         .dev_release    = spi_controller_release,
1945         .dev_groups     = spi_master_groups,
1946 };
1947
1948 #ifdef CONFIG_SPI_SLAVE
1949 /**
1950  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
1951  *                   controller
1952  * @spi: device used for the current transfer
1953  */
1954 int spi_slave_abort(struct spi_device *spi)
1955 {
1956         struct spi_controller *ctlr = spi->controller;
1957
1958         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
1959                 return ctlr->slave_abort(ctlr);
1960
1961         return -ENOTSUPP;
1962 }
1963 EXPORT_SYMBOL_GPL(spi_slave_abort);
1964
1965 static int match_true(struct device *dev, void *data)
1966 {
1967         return 1;
1968 }
1969
1970 static ssize_t spi_slave_show(struct device *dev,
1971                               struct device_attribute *attr, char *buf)
1972 {
1973         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1974                                                    dev);
1975         struct device *child;
1976
1977         child = device_find_child(&ctlr->dev, NULL, match_true);
1978         return sprintf(buf, "%s\n",
1979                        child ? to_spi_device(child)->modalias : NULL);
1980 }
1981
1982 static ssize_t spi_slave_store(struct device *dev,
1983                                struct device_attribute *attr, const char *buf,
1984                                size_t count)
1985 {
1986         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1987                                                    dev);
1988         struct spi_device *spi;
1989         struct device *child;
1990         char name[32];
1991         int rc;
1992
1993         rc = sscanf(buf, "%31s", name);
1994         if (rc != 1 || !name[0])
1995                 return -EINVAL;
1996
1997         child = device_find_child(&ctlr->dev, NULL, match_true);
1998         if (child) {
1999                 /* Remove registered slave */
2000                 device_unregister(child);
2001                 put_device(child);
2002         }
2003
2004         if (strcmp(name, "(null)")) {
2005                 /* Register new slave */
2006                 spi = spi_alloc_device(ctlr);
2007                 if (!spi)
2008                         return -ENOMEM;
2009
2010                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2011
2012                 rc = spi_add_device(spi);
2013                 if (rc) {
2014                         spi_dev_put(spi);
2015                         return rc;
2016                 }
2017         }
2018
2019         return count;
2020 }
2021
2022 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
2023
2024 static struct attribute *spi_slave_attrs[] = {
2025         &dev_attr_slave.attr,
2026         NULL,
2027 };
2028
2029 static const struct attribute_group spi_slave_group = {
2030         .attrs = spi_slave_attrs,
2031 };
2032
2033 static const struct attribute_group *spi_slave_groups[] = {
2034         &spi_controller_statistics_group,
2035         &spi_slave_group,
2036         NULL,
2037 };
2038
2039 static struct class spi_slave_class = {
2040         .name           = "spi_slave",
2041         .owner          = THIS_MODULE,
2042         .dev_release    = spi_controller_release,
2043         .dev_groups     = spi_slave_groups,
2044 };
2045 #else
2046 extern struct class spi_slave_class;    /* dummy */
2047 #endif
2048
2049 /**
2050  * __spi_alloc_controller - allocate an SPI master or slave controller
2051  * @dev: the controller, possibly using the platform_bus
2052  * @size: how much zeroed driver-private data to allocate; the pointer to this
2053  *      memory is in the driver_data field of the returned device,
2054  *      accessible with spi_controller_get_devdata().
2055  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2056  *      slave (true) controller
2057  * Context: can sleep
2058  *
2059  * This call is used only by SPI controller drivers, which are the
2060  * only ones directly touching chip registers.  It's how they allocate
2061  * an spi_controller structure, prior to calling spi_register_controller().
2062  *
2063  * This must be called from context that can sleep.
2064  *
2065  * The caller is responsible for assigning the bus number and initializing the
2066  * controller's methods before calling spi_register_controller(); and (after
2067  * errors adding the device) calling spi_controller_put() to prevent a memory
2068  * leak.
2069  *
2070  * Return: the SPI controller structure on success, else NULL.
2071  */
2072 struct spi_controller *__spi_alloc_controller(struct device *dev,
2073                                               unsigned int size, bool slave)
2074 {
2075         struct spi_controller   *ctlr;
2076
2077         if (!dev)
2078                 return NULL;
2079
2080         ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
2081         if (!ctlr)
2082                 return NULL;
2083
2084         device_initialize(&ctlr->dev);
2085         ctlr->bus_num = -1;
2086         ctlr->num_chipselect = 1;
2087         ctlr->slave = slave;
2088         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2089                 ctlr->dev.class = &spi_slave_class;
2090         else
2091                 ctlr->dev.class = &spi_master_class;
2092         ctlr->dev.parent = dev;
2093         pm_suspend_ignore_children(&ctlr->dev, true);
2094         spi_controller_set_devdata(ctlr, &ctlr[1]);
2095
2096         return ctlr;
2097 }
2098 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2099
2100 #ifdef CONFIG_OF
2101 static int of_spi_register_master(struct spi_controller *ctlr)
2102 {
2103         int nb, i, *cs;
2104         struct device_node *np = ctlr->dev.of_node;
2105
2106         if (!np)
2107                 return 0;
2108
2109         nb = of_gpio_named_count(np, "cs-gpios");
2110         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2111
2112         /* Return error only for an incorrectly formed cs-gpios property */
2113         if (nb == 0 || nb == -ENOENT)
2114                 return 0;
2115         else if (nb < 0)
2116                 return nb;
2117
2118         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2119                           GFP_KERNEL);
2120         ctlr->cs_gpios = cs;
2121
2122         if (!ctlr->cs_gpios)
2123                 return -ENOMEM;
2124
2125         for (i = 0; i < ctlr->num_chipselect; i++)
2126                 cs[i] = -ENOENT;
2127
2128         for (i = 0; i < nb; i++)
2129                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2130
2131         return 0;
2132 }
2133 #else
2134 static int of_spi_register_master(struct spi_controller *ctlr)
2135 {
2136         return 0;
2137 }
2138 #endif
2139
2140 static int spi_controller_check_ops(struct spi_controller *ctlr)
2141 {
2142         /*
2143          * The controller may implement only the high-level SPI-memory like
2144          * operations if it does not support regular SPI transfers, and this is
2145          * valid use case.
2146          * If ->mem_ops is NULL, we request that at least one of the
2147          * ->transfer_xxx() method be implemented.
2148          */
2149         if (ctlr->mem_ops) {
2150                 if (!ctlr->mem_ops->exec_op)
2151                         return -EINVAL;
2152         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2153                    !ctlr->transfer_one_message) {
2154                 return -EINVAL;
2155         }
2156
2157         return 0;
2158 }
2159
2160 /**
2161  * spi_register_controller - register SPI master or slave controller
2162  * @ctlr: initialized master, originally from spi_alloc_master() or
2163  *      spi_alloc_slave()
2164  * Context: can sleep
2165  *
2166  * SPI controllers connect to their drivers using some non-SPI bus,
2167  * such as the platform bus.  The final stage of probe() in that code
2168  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2169  *
2170  * SPI controllers use board specific (often SOC specific) bus numbers,
2171  * and board-specific addressing for SPI devices combines those numbers
2172  * with chip select numbers.  Since SPI does not directly support dynamic
2173  * device identification, boards need configuration tables telling which
2174  * chip is at which address.
2175  *
2176  * This must be called from context that can sleep.  It returns zero on
2177  * success, else a negative error code (dropping the controller's refcount).
2178  * After a successful return, the caller is responsible for calling
2179  * spi_unregister_controller().
2180  *
2181  * Return: zero on success, else a negative error code.
2182  */
2183 int spi_register_controller(struct spi_controller *ctlr)
2184 {
2185         struct device           *dev = ctlr->dev.parent;
2186         struct boardinfo        *bi;
2187         int                     status = -ENODEV;
2188         int                     id, first_dynamic;
2189
2190         if (!dev)
2191                 return -ENODEV;
2192
2193         /*
2194          * Make sure all necessary hooks are implemented before registering
2195          * the SPI controller.
2196          */
2197         status = spi_controller_check_ops(ctlr);
2198         if (status)
2199                 return status;
2200
2201         if (!spi_controller_is_slave(ctlr)) {
2202                 status = of_spi_register_master(ctlr);
2203                 if (status)
2204                         return status;
2205         }
2206
2207         /* even if it's just one always-selected device, there must
2208          * be at least one chipselect
2209          */
2210         if (ctlr->num_chipselect == 0)
2211                 return -EINVAL;
2212         if (ctlr->bus_num >= 0) {
2213                 /* devices with a fixed bus num must check-in with the num */
2214                 mutex_lock(&board_lock);
2215                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2216                         ctlr->bus_num + 1, GFP_KERNEL);
2217                 mutex_unlock(&board_lock);
2218                 if (WARN(id < 0, "couldn't get idr"))
2219                         return id == -ENOSPC ? -EBUSY : id;
2220                 ctlr->bus_num = id;
2221         } else if (ctlr->dev.of_node) {
2222                 /* allocate dynamic bus number using Linux idr */
2223                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2224                 if (id >= 0) {
2225                         ctlr->bus_num = id;
2226                         mutex_lock(&board_lock);
2227                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2228                                        ctlr->bus_num + 1, GFP_KERNEL);
2229                         mutex_unlock(&board_lock);
2230                         if (WARN(id < 0, "couldn't get idr"))
2231                                 return id == -ENOSPC ? -EBUSY : id;
2232                 }
2233         }
2234         if (ctlr->bus_num < 0) {
2235                 first_dynamic = of_alias_get_highest_id("spi");
2236                 if (first_dynamic < 0)
2237                         first_dynamic = 0;
2238                 else
2239                         first_dynamic++;
2240
2241                 mutex_lock(&board_lock);
2242                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2243                                0, GFP_KERNEL);
2244                 mutex_unlock(&board_lock);
2245                 if (WARN(id < 0, "couldn't get idr"))
2246                         return id;
2247                 ctlr->bus_num = id;
2248         }
2249         INIT_LIST_HEAD(&ctlr->queue);
2250         spin_lock_init(&ctlr->queue_lock);
2251         spin_lock_init(&ctlr->bus_lock_spinlock);
2252         mutex_init(&ctlr->bus_lock_mutex);
2253         mutex_init(&ctlr->io_mutex);
2254         ctlr->bus_lock_flag = 0;
2255         init_completion(&ctlr->xfer_completion);
2256         if (!ctlr->max_dma_len)
2257                 ctlr->max_dma_len = INT_MAX;
2258
2259         /* register the device, then userspace will see it.
2260          * registration fails if the bus ID is in use.
2261          */
2262         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2263         status = device_add(&ctlr->dev);
2264         if (status < 0) {
2265                 /* free bus id */
2266                 mutex_lock(&board_lock);
2267                 idr_remove(&spi_master_idr, ctlr->bus_num);
2268                 mutex_unlock(&board_lock);
2269                 goto done;
2270         }
2271         dev_dbg(dev, "registered %s %s\n",
2272                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2273                         dev_name(&ctlr->dev));
2274
2275         /*
2276          * If we're using a queued driver, start the queue. Note that we don't
2277          * need the queueing logic if the driver is only supporting high-level
2278          * memory operations.
2279          */
2280         if (ctlr->transfer) {
2281                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2282         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2283                 status = spi_controller_initialize_queue(ctlr);
2284                 if (status) {
2285                         device_del(&ctlr->dev);
2286                         /* free bus id */
2287                         mutex_lock(&board_lock);
2288                         idr_remove(&spi_master_idr, ctlr->bus_num);
2289                         mutex_unlock(&board_lock);
2290                         goto done;
2291                 }
2292         }
2293         /* add statistics */
2294         spin_lock_init(&ctlr->statistics.lock);
2295
2296         mutex_lock(&board_lock);
2297         list_add_tail(&ctlr->list, &spi_controller_list);
2298         list_for_each_entry(bi, &board_list, list)
2299                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2300         mutex_unlock(&board_lock);
2301
2302         /* Register devices from the device tree and ACPI */
2303         of_register_spi_devices(ctlr);
2304         acpi_register_spi_devices(ctlr);
2305 done:
2306         return status;
2307 }
2308 EXPORT_SYMBOL_GPL(spi_register_controller);
2309
2310 static void devm_spi_unregister(struct device *dev, void *res)
2311 {
2312         spi_unregister_controller(*(struct spi_controller **)res);
2313 }
2314
2315 /**
2316  * devm_spi_register_controller - register managed SPI master or slave
2317  *      controller
2318  * @dev:    device managing SPI controller
2319  * @ctlr: initialized controller, originally from spi_alloc_master() or
2320  *      spi_alloc_slave()
2321  * Context: can sleep
2322  *
2323  * Register a SPI device as with spi_register_controller() which will
2324  * automatically be unregistered and freed.
2325  *
2326  * Return: zero on success, else a negative error code.
2327  */
2328 int devm_spi_register_controller(struct device *dev,
2329                                  struct spi_controller *ctlr)
2330 {
2331         struct spi_controller **ptr;
2332         int ret;
2333
2334         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2335         if (!ptr)
2336                 return -ENOMEM;
2337
2338         ret = spi_register_controller(ctlr);
2339         if (!ret) {
2340                 *ptr = ctlr;
2341                 devres_add(dev, ptr);
2342         } else {
2343                 devres_free(ptr);
2344         }
2345
2346         return ret;
2347 }
2348 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2349
2350 static int __unregister(struct device *dev, void *null)
2351 {
2352         spi_unregister_device(to_spi_device(dev));
2353         return 0;
2354 }
2355
2356 /**
2357  * spi_unregister_controller - unregister SPI master or slave controller
2358  * @ctlr: the controller being unregistered
2359  * Context: can sleep
2360  *
2361  * This call is used only by SPI controller drivers, which are the
2362  * only ones directly touching chip registers.
2363  *
2364  * This must be called from context that can sleep.
2365  *
2366  * Note that this function also drops a reference to the controller.
2367  */
2368 void spi_unregister_controller(struct spi_controller *ctlr)
2369 {
2370         struct spi_controller *found;
2371         int id = ctlr->bus_num;
2372         int dummy;
2373
2374         /* First make sure that this controller was ever added */
2375         mutex_lock(&board_lock);
2376         found = idr_find(&spi_master_idr, id);
2377         mutex_unlock(&board_lock);
2378         if (ctlr->queued) {
2379                 if (spi_destroy_queue(ctlr))
2380                         dev_err(&ctlr->dev, "queue remove failed\n");
2381         }
2382         mutex_lock(&board_lock);
2383         list_del(&ctlr->list);
2384         mutex_unlock(&board_lock);
2385
2386         dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2387         device_unregister(&ctlr->dev);
2388         /* free bus id */
2389         mutex_lock(&board_lock);
2390         if (found == ctlr)
2391                 idr_remove(&spi_master_idr, id);
2392         mutex_unlock(&board_lock);
2393 }
2394 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2395
2396 int spi_controller_suspend(struct spi_controller *ctlr)
2397 {
2398         int ret;
2399
2400         /* Basically no-ops for non-queued controllers */
2401         if (!ctlr->queued)
2402                 return 0;
2403
2404         ret = spi_stop_queue(ctlr);
2405         if (ret)
2406                 dev_err(&ctlr->dev, "queue stop failed\n");
2407
2408         return ret;
2409 }
2410 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2411
2412 int spi_controller_resume(struct spi_controller *ctlr)
2413 {
2414         int ret;
2415
2416         if (!ctlr->queued)
2417                 return 0;
2418
2419         ret = spi_start_queue(ctlr);
2420         if (ret)
2421                 dev_err(&ctlr->dev, "queue restart failed\n");
2422
2423         return ret;
2424 }
2425 EXPORT_SYMBOL_GPL(spi_controller_resume);
2426
2427 static int __spi_controller_match(struct device *dev, const void *data)
2428 {
2429         struct spi_controller *ctlr;
2430         const u16 *bus_num = data;
2431
2432         ctlr = container_of(dev, struct spi_controller, dev);
2433         return ctlr->bus_num == *bus_num;
2434 }
2435
2436 /**
2437  * spi_busnum_to_master - look up master associated with bus_num
2438  * @bus_num: the master's bus number
2439  * Context: can sleep
2440  *
2441  * This call may be used with devices that are registered after
2442  * arch init time.  It returns a refcounted pointer to the relevant
2443  * spi_controller (which the caller must release), or NULL if there is
2444  * no such master registered.
2445  *
2446  * Return: the SPI master structure on success, else NULL.
2447  */
2448 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2449 {
2450         struct device           *dev;
2451         struct spi_controller   *ctlr = NULL;
2452
2453         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2454                                 __spi_controller_match);
2455         if (dev)
2456                 ctlr = container_of(dev, struct spi_controller, dev);
2457         /* reference got in class_find_device */
2458         return ctlr;
2459 }
2460 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2461
2462 /*-------------------------------------------------------------------------*/
2463
2464 /* Core methods for SPI resource management */
2465
2466 /**
2467  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2468  *                 during the processing of a spi_message while using
2469  *                 spi_transfer_one
2470  * @spi:     the spi device for which we allocate memory
2471  * @release: the release code to execute for this resource
2472  * @size:    size to alloc and return
2473  * @gfp:     GFP allocation flags
2474  *
2475  * Return: the pointer to the allocated data
2476  *
2477  * This may get enhanced in the future to allocate from a memory pool
2478  * of the @spi_device or @spi_controller to avoid repeated allocations.
2479  */
2480 void *spi_res_alloc(struct spi_device *spi,
2481                     spi_res_release_t release,
2482                     size_t size, gfp_t gfp)
2483 {
2484         struct spi_res *sres;
2485
2486         sres = kzalloc(sizeof(*sres) + size, gfp);
2487         if (!sres)
2488                 return NULL;
2489
2490         INIT_LIST_HEAD(&sres->entry);
2491         sres->release = release;
2492
2493         return sres->data;
2494 }
2495 EXPORT_SYMBOL_GPL(spi_res_alloc);
2496
2497 /**
2498  * spi_res_free - free an spi resource
2499  * @res: pointer to the custom data of a resource
2500  *
2501  */
2502 void spi_res_free(void *res)
2503 {
2504         struct spi_res *sres = container_of(res, struct spi_res, data);
2505
2506         if (!res)
2507                 return;
2508
2509         WARN_ON(!list_empty(&sres->entry));
2510         kfree(sres);
2511 }
2512 EXPORT_SYMBOL_GPL(spi_res_free);
2513
2514 /**
2515  * spi_res_add - add a spi_res to the spi_message
2516  * @message: the spi message
2517  * @res:     the spi_resource
2518  */
2519 void spi_res_add(struct spi_message *message, void *res)
2520 {
2521         struct spi_res *sres = container_of(res, struct spi_res, data);
2522
2523         WARN_ON(!list_empty(&sres->entry));
2524         list_add_tail(&sres->entry, &message->resources);
2525 }
2526 EXPORT_SYMBOL_GPL(spi_res_add);
2527
2528 /**
2529  * spi_res_release - release all spi resources for this message
2530  * @ctlr:  the @spi_controller
2531  * @message: the @spi_message
2532  */
2533 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2534 {
2535         struct spi_res *res;
2536
2537         while (!list_empty(&message->resources)) {
2538                 res = list_last_entry(&message->resources,
2539                                       struct spi_res, entry);
2540
2541                 if (res->release)
2542                         res->release(ctlr, message, res->data);
2543
2544                 list_del(&res->entry);
2545
2546                 kfree(res);
2547         }
2548 }
2549 EXPORT_SYMBOL_GPL(spi_res_release);
2550
2551 /*-------------------------------------------------------------------------*/
2552
2553 /* Core methods for spi_message alterations */
2554
2555 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2556                                             struct spi_message *msg,
2557                                             void *res)
2558 {
2559         struct spi_replaced_transfers *rxfer = res;
2560         size_t i;
2561
2562         /* call extra callback if requested */
2563         if (rxfer->release)
2564                 rxfer->release(ctlr, msg, res);
2565
2566         /* insert replaced transfers back into the message */
2567         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2568
2569         /* remove the formerly inserted entries */
2570         for (i = 0; i < rxfer->inserted; i++)
2571                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2572 }
2573
2574 /**
2575  * spi_replace_transfers - replace transfers with several transfers
2576  *                         and register change with spi_message.resources
2577  * @msg:           the spi_message we work upon
2578  * @xfer_first:    the first spi_transfer we want to replace
2579  * @remove:        number of transfers to remove
2580  * @insert:        the number of transfers we want to insert instead
2581  * @release:       extra release code necessary in some circumstances
2582  * @extradatasize: extra data to allocate (with alignment guarantees
2583  *                 of struct @spi_transfer)
2584  * @gfp:           gfp flags
2585  *
2586  * Returns: pointer to @spi_replaced_transfers,
2587  *          PTR_ERR(...) in case of errors.
2588  */
2589 struct spi_replaced_transfers *spi_replace_transfers(
2590         struct spi_message *msg,
2591         struct spi_transfer *xfer_first,
2592         size_t remove,
2593         size_t insert,
2594         spi_replaced_release_t release,
2595         size_t extradatasize,
2596         gfp_t gfp)
2597 {
2598         struct spi_replaced_transfers *rxfer;
2599         struct spi_transfer *xfer;
2600         size_t i;
2601
2602         /* allocate the structure using spi_res */
2603         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2604                               insert * sizeof(struct spi_transfer)
2605                               + sizeof(struct spi_replaced_transfers)
2606                               + extradatasize,
2607                               gfp);
2608         if (!rxfer)
2609                 return ERR_PTR(-ENOMEM);
2610
2611         /* the release code to invoke before running the generic release */
2612         rxfer->release = release;
2613
2614         /* assign extradata */
2615         if (extradatasize)
2616                 rxfer->extradata =
2617                         &rxfer->inserted_transfers[insert];
2618
2619         /* init the replaced_transfers list */
2620         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2621
2622         /* assign the list_entry after which we should reinsert
2623          * the @replaced_transfers - it may be spi_message.messages!
2624          */
2625         rxfer->replaced_after = xfer_first->transfer_list.prev;
2626
2627         /* remove the requested number of transfers */
2628         for (i = 0; i < remove; i++) {
2629                 /* if the entry after replaced_after it is msg->transfers
2630                  * then we have been requested to remove more transfers
2631                  * than are in the list
2632                  */
2633                 if (rxfer->replaced_after->next == &msg->transfers) {
2634                         dev_err(&msg->spi->dev,
2635                                 "requested to remove more spi_transfers than are available\n");
2636                         /* insert replaced transfers back into the message */
2637                         list_splice(&rxfer->replaced_transfers,
2638                                     rxfer->replaced_after);
2639
2640                         /* free the spi_replace_transfer structure */
2641                         spi_res_free(rxfer);
2642
2643                         /* and return with an error */
2644                         return ERR_PTR(-EINVAL);
2645                 }
2646
2647                 /* remove the entry after replaced_after from list of
2648                  * transfers and add it to list of replaced_transfers
2649                  */
2650                 list_move_tail(rxfer->replaced_after->next,
2651                                &rxfer->replaced_transfers);
2652         }
2653
2654         /* create copy of the given xfer with identical settings
2655          * based on the first transfer to get removed
2656          */
2657         for (i = 0; i < insert; i++) {
2658                 /* we need to run in reverse order */
2659                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2660
2661                 /* copy all spi_transfer data */
2662                 memcpy(xfer, xfer_first, sizeof(*xfer));
2663
2664                 /* add to list */
2665                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2666
2667                 /* clear cs_change and delay_usecs for all but the last */
2668                 if (i) {
2669                         xfer->cs_change = false;
2670                         xfer->delay_usecs = 0;
2671                 }
2672         }
2673
2674         /* set up inserted */
2675         rxfer->inserted = insert;
2676
2677         /* and register it with spi_res/spi_message */
2678         spi_res_add(msg, rxfer);
2679
2680         return rxfer;
2681 }
2682 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2683
2684 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2685                                         struct spi_message *msg,
2686                                         struct spi_transfer **xferp,
2687                                         size_t maxsize,
2688                                         gfp_t gfp)
2689 {
2690         struct spi_transfer *xfer = *xferp, *xfers;
2691         struct spi_replaced_transfers *srt;
2692         size_t offset;
2693         size_t count, i;
2694
2695         /* warn once about this fact that we are splitting a transfer */
2696         dev_warn_once(&msg->spi->dev,
2697                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2698                       xfer->len, maxsize);
2699
2700         /* calculate how many we have to replace */
2701         count = DIV_ROUND_UP(xfer->len, maxsize);
2702
2703         /* create replacement */
2704         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2705         if (IS_ERR(srt))
2706                 return PTR_ERR(srt);
2707         xfers = srt->inserted_transfers;
2708
2709         /* now handle each of those newly inserted spi_transfers
2710          * note that the replacements spi_transfers all are preset
2711          * to the same values as *xferp, so tx_buf, rx_buf and len
2712          * are all identical (as well as most others)
2713          * so we just have to fix up len and the pointers.
2714          *
2715          * this also includes support for the depreciated
2716          * spi_message.is_dma_mapped interface
2717          */
2718
2719         /* the first transfer just needs the length modified, so we
2720          * run it outside the loop
2721          */
2722         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2723
2724         /* all the others need rx_buf/tx_buf also set */
2725         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2726                 /* update rx_buf, tx_buf and dma */
2727                 if (xfers[i].rx_buf)
2728                         xfers[i].rx_buf += offset;
2729                 if (xfers[i].rx_dma)
2730                         xfers[i].rx_dma += offset;
2731                 if (xfers[i].tx_buf)
2732                         xfers[i].tx_buf += offset;
2733                 if (xfers[i].tx_dma)
2734                         xfers[i].tx_dma += offset;
2735
2736                 /* update length */
2737                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2738         }
2739
2740         /* we set up xferp to the last entry we have inserted,
2741          * so that we skip those already split transfers
2742          */
2743         *xferp = &xfers[count - 1];
2744
2745         /* increment statistics counters */
2746         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2747                                        transfers_split_maxsize);
2748         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2749                                        transfers_split_maxsize);
2750
2751         return 0;
2752 }
2753
2754 /**
2755  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2756  *                              when an individual transfer exceeds a
2757  *                              certain size
2758  * @ctlr:    the @spi_controller for this transfer
2759  * @msg:   the @spi_message to transform
2760  * @maxsize:  the maximum when to apply this
2761  * @gfp: GFP allocation flags
2762  *
2763  * Return: status of transformation
2764  */
2765 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2766                                 struct spi_message *msg,
2767                                 size_t maxsize,
2768                                 gfp_t gfp)
2769 {
2770         struct spi_transfer *xfer;
2771         int ret;
2772
2773         /* iterate over the transfer_list,
2774          * but note that xfer is advanced to the last transfer inserted
2775          * to avoid checking sizes again unnecessarily (also xfer does
2776          * potentiall belong to a different list by the time the
2777          * replacement has happened
2778          */
2779         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2780                 if (xfer->len > maxsize) {
2781                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2782                                                            maxsize, gfp);
2783                         if (ret)
2784                                 return ret;
2785                 }
2786         }
2787
2788         return 0;
2789 }
2790 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2791
2792 /*-------------------------------------------------------------------------*/
2793
2794 /* Core methods for SPI controller protocol drivers.  Some of the
2795  * other core methods are currently defined as inline functions.
2796  */
2797
2798 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2799                                         u8 bits_per_word)
2800 {
2801         if (ctlr->bits_per_word_mask) {
2802                 /* Only 32 bits fit in the mask */
2803                 if (bits_per_word > 32)
2804                         return -EINVAL;
2805                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2806                         return -EINVAL;
2807         }
2808
2809         return 0;
2810 }
2811
2812 /**
2813  * spi_setup - setup SPI mode and clock rate
2814  * @spi: the device whose settings are being modified
2815  * Context: can sleep, and no requests are queued to the device
2816  *
2817  * SPI protocol drivers may need to update the transfer mode if the
2818  * device doesn't work with its default.  They may likewise need
2819  * to update clock rates or word sizes from initial values.  This function
2820  * changes those settings, and must be called from a context that can sleep.
2821  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2822  * effect the next time the device is selected and data is transferred to
2823  * or from it.  When this function returns, the spi device is deselected.
2824  *
2825  * Note that this call will fail if the protocol driver specifies an option
2826  * that the underlying controller or its driver does not support.  For
2827  * example, not all hardware supports wire transfers using nine bit words,
2828  * LSB-first wire encoding, or active-high chipselects.
2829  *
2830  * Return: zero on success, else a negative error code.
2831  */
2832 int spi_setup(struct spi_device *spi)
2833 {
2834         unsigned        bad_bits, ugly_bits;
2835         int             status;
2836
2837         /* check mode to prevent that DUAL and QUAD set at the same time
2838          */
2839         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2840                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2841                 dev_err(&spi->dev,
2842                 "setup: can not select dual and quad at the same time\n");
2843                 return -EINVAL;
2844         }
2845         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2846          */
2847         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2848                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
2849                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
2850                 return -EINVAL;
2851         /* help drivers fail *cleanly* when they need options
2852          * that aren't supported with their current controller
2853          * SPI_CS_WORD has a fallback software implementation,
2854          * so it is ignored here.
2855          */
2856         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
2857         ugly_bits = bad_bits &
2858                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
2859                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
2860         if (ugly_bits) {
2861                 dev_warn(&spi->dev,
2862                          "setup: ignoring unsupported mode bits %x\n",
2863                          ugly_bits);
2864                 spi->mode &= ~ugly_bits;
2865                 bad_bits &= ~ugly_bits;
2866         }
2867         if (bad_bits) {
2868                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2869                         bad_bits);
2870                 return -EINVAL;
2871         }
2872
2873         if (!spi->bits_per_word)
2874                 spi->bits_per_word = 8;
2875
2876         status = __spi_validate_bits_per_word(spi->controller,
2877                                               spi->bits_per_word);
2878         if (status)
2879                 return status;
2880
2881         if (!spi->max_speed_hz)
2882                 spi->max_speed_hz = spi->controller->max_speed_hz;
2883
2884         if (spi->controller->setup)
2885                 status = spi->controller->setup(spi);
2886
2887         spi_set_cs(spi, false);
2888
2889         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2890                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2891                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2892                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2893                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2894                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2895                         spi->bits_per_word, spi->max_speed_hz,
2896                         status);
2897
2898         return status;
2899 }
2900 EXPORT_SYMBOL_GPL(spi_setup);
2901
2902 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2903 {
2904         struct spi_controller *ctlr = spi->controller;
2905         struct spi_transfer *xfer;
2906         int w_size;
2907
2908         if (list_empty(&message->transfers))
2909                 return -EINVAL;
2910
2911         /* If an SPI controller does not support toggling the CS line on each
2912          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
2913          * for the CS line, we can emulate the CS-per-word hardware function by
2914          * splitting transfers into one-word transfers and ensuring that
2915          * cs_change is set for each transfer.
2916          */
2917         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
2918                                           gpio_is_valid(spi->cs_gpio))) {
2919                 size_t maxsize;
2920                 int ret;
2921
2922                 maxsize = (spi->bits_per_word + 7) / 8;
2923
2924                 /* spi_split_transfers_maxsize() requires message->spi */
2925                 message->spi = spi;
2926
2927                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
2928                                                   GFP_KERNEL);
2929                 if (ret)
2930                         return ret;
2931
2932                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2933                         /* don't change cs_change on the last entry in the list */
2934                         if (list_is_last(&xfer->transfer_list, &message->transfers))
2935                                 break;
2936                         xfer->cs_change = 1;
2937                 }
2938         }
2939
2940         /* Half-duplex links include original MicroWire, and ones with
2941          * only one data pin like SPI_3WIRE (switches direction) or where
2942          * either MOSI or MISO is missing.  They can also be caused by
2943          * software limitations.
2944          */
2945         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
2946             (spi->mode & SPI_3WIRE)) {
2947                 unsigned flags = ctlr->flags;
2948
2949                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2950                         if (xfer->rx_buf && xfer->tx_buf)
2951                                 return -EINVAL;
2952                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
2953                                 return -EINVAL;
2954                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
2955                                 return -EINVAL;
2956                 }
2957         }
2958
2959         /**
2960          * Set transfer bits_per_word and max speed as spi device default if
2961          * it is not set for this transfer.
2962          * Set transfer tx_nbits and rx_nbits as single transfer default
2963          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2964          */
2965         message->frame_length = 0;
2966         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2967                 message->frame_length += xfer->len;
2968                 if (!xfer->bits_per_word)
2969                         xfer->bits_per_word = spi->bits_per_word;
2970
2971                 if (!xfer->speed_hz)
2972                         xfer->speed_hz = spi->max_speed_hz;
2973                 if (!xfer->speed_hz)
2974                         xfer->speed_hz = ctlr->max_speed_hz;
2975
2976                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
2977                         xfer->speed_hz = ctlr->max_speed_hz;
2978
2979                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
2980                         return -EINVAL;
2981
2982                 /*
2983                  * SPI transfer length should be multiple of SPI word size
2984                  * where SPI word size should be power-of-two multiple
2985                  */
2986                 if (xfer->bits_per_word <= 8)
2987                         w_size = 1;
2988                 else if (xfer->bits_per_word <= 16)
2989                         w_size = 2;
2990                 else
2991                         w_size = 4;
2992
2993                 /* No partial transfers accepted */
2994                 if (xfer->len % w_size)
2995                         return -EINVAL;
2996
2997                 if (xfer->speed_hz && ctlr->min_speed_hz &&
2998                     xfer->speed_hz < ctlr->min_speed_hz)
2999                         return -EINVAL;
3000
3001                 if (xfer->tx_buf && !xfer->tx_nbits)
3002                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3003                 if (xfer->rx_buf && !xfer->rx_nbits)
3004                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3005                 /* check transfer tx/rx_nbits:
3006                  * 1. check the value matches one of single, dual and quad
3007                  * 2. check tx/rx_nbits match the mode in spi_device
3008                  */
3009                 if (xfer->tx_buf) {
3010                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3011                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3012                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3013                                 return -EINVAL;
3014                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3015                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3016                                 return -EINVAL;
3017                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3018                                 !(spi->mode & SPI_TX_QUAD))
3019                                 return -EINVAL;
3020                 }
3021                 /* check transfer rx_nbits */
3022                 if (xfer->rx_buf) {
3023                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3024                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3025                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3026                                 return -EINVAL;
3027                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3028                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3029                                 return -EINVAL;
3030                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3031                                 !(spi->mode & SPI_RX_QUAD))
3032                                 return -EINVAL;
3033                 }
3034         }
3035
3036         message->status = -EINPROGRESS;
3037
3038         return 0;
3039 }
3040
3041 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3042 {
3043         struct spi_controller *ctlr = spi->controller;
3044
3045         /*
3046          * Some controllers do not support doing regular SPI transfers. Return
3047          * ENOTSUPP when this is the case.
3048          */
3049         if (!ctlr->transfer)
3050                 return -ENOTSUPP;
3051
3052         message->spi = spi;
3053
3054         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3055         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3056
3057         trace_spi_message_submit(message);
3058
3059         return ctlr->transfer(spi, message);
3060 }
3061
3062 /**
3063  * spi_async - asynchronous SPI transfer
3064  * @spi: device with which data will be exchanged
3065  * @message: describes the data transfers, including completion callback
3066  * Context: any (irqs may be blocked, etc)
3067  *
3068  * This call may be used in_irq and other contexts which can't sleep,
3069  * as well as from task contexts which can sleep.
3070  *
3071  * The completion callback is invoked in a context which can't sleep.
3072  * Before that invocation, the value of message->status is undefined.
3073  * When the callback is issued, message->status holds either zero (to
3074  * indicate complete success) or a negative error code.  After that
3075  * callback returns, the driver which issued the transfer request may
3076  * deallocate the associated memory; it's no longer in use by any SPI
3077  * core or controller driver code.
3078  *
3079  * Note that although all messages to a spi_device are handled in
3080  * FIFO order, messages may go to different devices in other orders.
3081  * Some device might be higher priority, or have various "hard" access
3082  * time requirements, for example.
3083  *
3084  * On detection of any fault during the transfer, processing of
3085  * the entire message is aborted, and the device is deselected.
3086  * Until returning from the associated message completion callback,
3087  * no other spi_message queued to that device will be processed.
3088  * (This rule applies equally to all the synchronous transfer calls,
3089  * which are wrappers around this core asynchronous primitive.)
3090  *
3091  * Return: zero on success, else a negative error code.
3092  */
3093 int spi_async(struct spi_device *spi, struct spi_message *message)
3094 {
3095         struct spi_controller *ctlr = spi->controller;
3096         int ret;
3097         unsigned long flags;
3098
3099         ret = __spi_validate(spi, message);
3100         if (ret != 0)
3101                 return ret;
3102
3103         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3104
3105         if (ctlr->bus_lock_flag)
3106                 ret = -EBUSY;
3107         else
3108                 ret = __spi_async(spi, message);
3109
3110         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3111
3112         return ret;
3113 }
3114 EXPORT_SYMBOL_GPL(spi_async);
3115
3116 /**
3117  * spi_async_locked - version of spi_async with exclusive bus usage
3118  * @spi: device with which data will be exchanged
3119  * @message: describes the data transfers, including completion callback
3120  * Context: any (irqs may be blocked, etc)
3121  *
3122  * This call may be used in_irq and other contexts which can't sleep,
3123  * as well as from task contexts which can sleep.
3124  *
3125  * The completion callback is invoked in a context which can't sleep.
3126  * Before that invocation, the value of message->status is undefined.
3127  * When the callback is issued, message->status holds either zero (to
3128  * indicate complete success) or a negative error code.  After that
3129  * callback returns, the driver which issued the transfer request may
3130  * deallocate the associated memory; it's no longer in use by any SPI
3131  * core or controller driver code.
3132  *
3133  * Note that although all messages to a spi_device are handled in
3134  * FIFO order, messages may go to different devices in other orders.
3135  * Some device might be higher priority, or have various "hard" access
3136  * time requirements, for example.
3137  *
3138  * On detection of any fault during the transfer, processing of
3139  * the entire message is aborted, and the device is deselected.
3140  * Until returning from the associated message completion callback,
3141  * no other spi_message queued to that device will be processed.
3142  * (This rule applies equally to all the synchronous transfer calls,
3143  * which are wrappers around this core asynchronous primitive.)
3144  *
3145  * Return: zero on success, else a negative error code.
3146  */
3147 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3148 {
3149         struct spi_controller *ctlr = spi->controller;
3150         int ret;
3151         unsigned long flags;
3152
3153         ret = __spi_validate(spi, message);
3154         if (ret != 0)
3155                 return ret;
3156
3157         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3158
3159         ret = __spi_async(spi, message);
3160
3161         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3162
3163         return ret;
3164
3165 }
3166 EXPORT_SYMBOL_GPL(spi_async_locked);
3167
3168 /*-------------------------------------------------------------------------*/
3169
3170 /* Utility methods for SPI protocol drivers, layered on
3171  * top of the core.  Some other utility methods are defined as
3172  * inline functions.
3173  */
3174
3175 static void spi_complete(void *arg)
3176 {
3177         complete(arg);
3178 }
3179
3180 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3181 {
3182         DECLARE_COMPLETION_ONSTACK(done);
3183         int status;
3184         struct spi_controller *ctlr = spi->controller;
3185         unsigned long flags;
3186
3187         status = __spi_validate(spi, message);
3188         if (status != 0)
3189                 return status;
3190
3191         message->complete = spi_complete;
3192         message->context = &done;
3193         message->spi = spi;
3194
3195         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3196         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3197
3198         /* If we're not using the legacy transfer method then we will
3199          * try to transfer in the calling context so special case.
3200          * This code would be less tricky if we could remove the
3201          * support for driver implemented message queues.
3202          */
3203         if (ctlr->transfer == spi_queued_transfer) {
3204                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3205
3206                 trace_spi_message_submit(message);
3207
3208                 status = __spi_queued_transfer(spi, message, false);
3209
3210                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3211         } else {
3212                 status = spi_async_locked(spi, message);
3213         }
3214
3215         if (status == 0) {
3216                 /* Push out the messages in the calling context if we
3217                  * can.
3218                  */
3219                 if (ctlr->transfer == spi_queued_transfer) {
3220                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3221                                                        spi_sync_immediate);
3222                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3223                                                        spi_sync_immediate);
3224                         __spi_pump_messages(ctlr, false);
3225                 }
3226
3227                 wait_for_completion(&done);
3228                 status = message->status;
3229         }
3230         message->context = NULL;
3231         return status;
3232 }
3233
3234 /**
3235  * spi_sync - blocking/synchronous SPI data transfers
3236  * @spi: device with which data will be exchanged
3237  * @message: describes the data transfers
3238  * Context: can sleep
3239  *
3240  * This call may only be used from a context that may sleep.  The sleep
3241  * is non-interruptible, and has no timeout.  Low-overhead controller
3242  * drivers may DMA directly into and out of the message buffers.
3243  *
3244  * Note that the SPI device's chip select is active during the message,
3245  * and then is normally disabled between messages.  Drivers for some
3246  * frequently-used devices may want to minimize costs of selecting a chip,
3247  * by leaving it selected in anticipation that the next message will go
3248  * to the same chip.  (That may increase power usage.)
3249  *
3250  * Also, the caller is guaranteeing that the memory associated with the
3251  * message will not be freed before this call returns.
3252  *
3253  * Return: zero on success, else a negative error code.
3254  */
3255 int spi_sync(struct spi_device *spi, struct spi_message *message)
3256 {
3257         int ret;
3258
3259         mutex_lock(&spi->controller->bus_lock_mutex);
3260         ret = __spi_sync(spi, message);
3261         mutex_unlock(&spi->controller->bus_lock_mutex);
3262
3263         return ret;
3264 }
3265 EXPORT_SYMBOL_GPL(spi_sync);
3266
3267 /**
3268  * spi_sync_locked - version of spi_sync with exclusive bus usage
3269  * @spi: device with which data will be exchanged
3270  * @message: describes the data transfers
3271  * Context: can sleep
3272  *
3273  * This call may only be used from a context that may sleep.  The sleep
3274  * is non-interruptible, and has no timeout.  Low-overhead controller
3275  * drivers may DMA directly into and out of the message buffers.
3276  *
3277  * This call should be used by drivers that require exclusive access to the
3278  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3279  * be released by a spi_bus_unlock call when the exclusive access is over.
3280  *
3281  * Return: zero on success, else a negative error code.
3282  */
3283 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3284 {
3285         return __spi_sync(spi, message);
3286 }
3287 EXPORT_SYMBOL_GPL(spi_sync_locked);
3288
3289 /**
3290  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3291  * @ctlr: SPI bus master that should be locked for exclusive bus access
3292  * Context: can sleep
3293  *
3294  * This call may only be used from a context that may sleep.  The sleep
3295  * is non-interruptible, and has no timeout.
3296  *
3297  * This call should be used by drivers that require exclusive access to the
3298  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3299  * exclusive access is over. Data transfer must be done by spi_sync_locked
3300  * and spi_async_locked calls when the SPI bus lock is held.
3301  *
3302  * Return: always zero.
3303  */
3304 int spi_bus_lock(struct spi_controller *ctlr)
3305 {
3306         unsigned long flags;
3307
3308         mutex_lock(&ctlr->bus_lock_mutex);
3309
3310         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3311         ctlr->bus_lock_flag = 1;
3312         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3313
3314         /* mutex remains locked until spi_bus_unlock is called */
3315
3316         return 0;
3317 }
3318 EXPORT_SYMBOL_GPL(spi_bus_lock);
3319
3320 /**
3321  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3322  * @ctlr: SPI bus master that was locked for exclusive bus access
3323  * Context: can sleep
3324  *
3325  * This call may only be used from a context that may sleep.  The sleep
3326  * is non-interruptible, and has no timeout.
3327  *
3328  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3329  * call.
3330  *
3331  * Return: always zero.
3332  */
3333 int spi_bus_unlock(struct spi_controller *ctlr)
3334 {
3335         ctlr->bus_lock_flag = 0;
3336
3337         mutex_unlock(&ctlr->bus_lock_mutex);
3338
3339         return 0;
3340 }
3341 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3342
3343 /* portable code must never pass more than 32 bytes */
3344 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3345
3346 static u8       *buf;
3347
3348 /**
3349  * spi_write_then_read - SPI synchronous write followed by read
3350  * @spi: device with which data will be exchanged
3351  * @txbuf: data to be written (need not be dma-safe)
3352  * @n_tx: size of txbuf, in bytes
3353  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3354  * @n_rx: size of rxbuf, in bytes
3355  * Context: can sleep
3356  *
3357  * This performs a half duplex MicroWire style transaction with the
3358  * device, sending txbuf and then reading rxbuf.  The return value
3359  * is zero for success, else a negative errno status code.
3360  * This call may only be used from a context that may sleep.
3361  *
3362  * Parameters to this routine are always copied using a small buffer;
3363  * portable code should never use this for more than 32 bytes.
3364  * Performance-sensitive or bulk transfer code should instead use
3365  * spi_{async,sync}() calls with dma-safe buffers.
3366  *
3367  * Return: zero on success, else a negative error code.
3368  */
3369 int spi_write_then_read(struct spi_device *spi,
3370                 const void *txbuf, unsigned n_tx,
3371                 void *rxbuf, unsigned n_rx)
3372 {
3373         static DEFINE_MUTEX(lock);
3374
3375         int                     status;
3376         struct spi_message      message;
3377         struct spi_transfer     x[2];
3378         u8                      *local_buf;
3379
3380         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3381          * copying here, (as a pure convenience thing), but we can
3382          * keep heap costs out of the hot path unless someone else is
3383          * using the pre-allocated buffer or the transfer is too large.
3384          */
3385         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3386                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3387                                     GFP_KERNEL | GFP_DMA);
3388                 if (!local_buf)
3389                         return -ENOMEM;
3390         } else {
3391                 local_buf = buf;
3392         }
3393
3394         spi_message_init(&message);
3395         memset(x, 0, sizeof(x));
3396         if (n_tx) {
3397                 x[0].len = n_tx;
3398                 spi_message_add_tail(&x[0], &message);
3399         }
3400         if (n_rx) {
3401                 x[1].len = n_rx;
3402                 spi_message_add_tail(&x[1], &message);
3403         }
3404
3405         memcpy(local_buf, txbuf, n_tx);
3406         x[0].tx_buf = local_buf;
3407         x[1].rx_buf = local_buf + n_tx;
3408
3409         /* do the i/o */
3410         status = spi_sync(spi, &message);
3411         if (status == 0)
3412                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3413
3414         if (x[0].tx_buf == buf)
3415                 mutex_unlock(&lock);
3416         else
3417                 kfree(local_buf);
3418
3419         return status;
3420 }
3421 EXPORT_SYMBOL_GPL(spi_write_then_read);
3422
3423 /*-------------------------------------------------------------------------*/
3424
3425 #if IS_ENABLED(CONFIG_OF)
3426 static int __spi_of_device_match(struct device *dev, void *data)
3427 {
3428         return dev->of_node == data;
3429 }
3430
3431 /* must call put_device() when done with returned spi_device device */
3432 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3433 {
3434         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3435                                                 __spi_of_device_match);
3436         return dev ? to_spi_device(dev) : NULL;
3437 }
3438 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3439 #endif /* IS_ENABLED(CONFIG_OF) */
3440
3441 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3442 static int __spi_of_controller_match(struct device *dev, const void *data)
3443 {
3444         return dev->of_node == data;
3445 }
3446
3447 /* the spi controllers are not using spi_bus, so we find it with another way */
3448 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3449 {
3450         struct device *dev;
3451
3452         dev = class_find_device(&spi_master_class, NULL, node,
3453                                 __spi_of_controller_match);
3454         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3455                 dev = class_find_device(&spi_slave_class, NULL, node,
3456                                         __spi_of_controller_match);
3457         if (!dev)
3458                 return NULL;
3459
3460         /* reference got in class_find_device */
3461         return container_of(dev, struct spi_controller, dev);
3462 }
3463
3464 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3465                          void *arg)
3466 {
3467         struct of_reconfig_data *rd = arg;
3468         struct spi_controller *ctlr;
3469         struct spi_device *spi;
3470
3471         switch (of_reconfig_get_state_change(action, arg)) {
3472         case OF_RECONFIG_CHANGE_ADD:
3473                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3474                 if (ctlr == NULL)
3475                         return NOTIFY_OK;       /* not for us */
3476
3477                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3478                         put_device(&ctlr->dev);
3479                         return NOTIFY_OK;
3480                 }
3481
3482                 spi = of_register_spi_device(ctlr, rd->dn);
3483                 put_device(&ctlr->dev);
3484
3485                 if (IS_ERR(spi)) {
3486                         pr_err("%s: failed to create for '%pOF'\n",
3487                                         __func__, rd->dn);
3488                         of_node_clear_flag(rd->dn, OF_POPULATED);
3489                         return notifier_from_errno(PTR_ERR(spi));
3490                 }
3491                 break;
3492
3493         case OF_RECONFIG_CHANGE_REMOVE:
3494                 /* already depopulated? */
3495                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3496                         return NOTIFY_OK;
3497
3498                 /* find our device by node */
3499                 spi = of_find_spi_device_by_node(rd->dn);
3500                 if (spi == NULL)
3501                         return NOTIFY_OK;       /* no? not meant for us */
3502
3503                 /* unregister takes one ref away */
3504                 spi_unregister_device(spi);
3505
3506                 /* and put the reference of the find */
3507                 put_device(&spi->dev);
3508                 break;
3509         }
3510
3511         return NOTIFY_OK;
3512 }
3513
3514 static struct notifier_block spi_of_notifier = {
3515         .notifier_call = of_spi_notify,
3516 };
3517 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3518 extern struct notifier_block spi_of_notifier;
3519 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3520
3521 #if IS_ENABLED(CONFIG_ACPI)
3522 static int spi_acpi_controller_match(struct device *dev, const void *data)
3523 {
3524         return ACPI_COMPANION(dev->parent) == data;
3525 }
3526
3527 static int spi_acpi_device_match(struct device *dev, void *data)
3528 {
3529         return ACPI_COMPANION(dev) == data;
3530 }
3531
3532 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3533 {
3534         struct device *dev;
3535
3536         dev = class_find_device(&spi_master_class, NULL, adev,
3537                                 spi_acpi_controller_match);
3538         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3539                 dev = class_find_device(&spi_slave_class, NULL, adev,
3540                                         spi_acpi_controller_match);
3541         if (!dev)
3542                 return NULL;
3543
3544         return container_of(dev, struct spi_controller, dev);
3545 }
3546
3547 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3548 {
3549         struct device *dev;
3550
3551         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3552
3553         return dev ? to_spi_device(dev) : NULL;
3554 }
3555
3556 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3557                            void *arg)
3558 {
3559         struct acpi_device *adev = arg;
3560         struct spi_controller *ctlr;
3561         struct spi_device *spi;
3562
3563         switch (value) {
3564         case ACPI_RECONFIG_DEVICE_ADD:
3565                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3566                 if (!ctlr)
3567                         break;
3568
3569                 acpi_register_spi_device(ctlr, adev);
3570                 put_device(&ctlr->dev);
3571                 break;
3572         case ACPI_RECONFIG_DEVICE_REMOVE:
3573                 if (!acpi_device_enumerated(adev))
3574                         break;
3575
3576                 spi = acpi_spi_find_device_by_adev(adev);
3577                 if (!spi)
3578                         break;
3579
3580                 spi_unregister_device(spi);
3581                 put_device(&spi->dev);
3582                 break;
3583         }
3584
3585         return NOTIFY_OK;
3586 }
3587
3588 static struct notifier_block spi_acpi_notifier = {
3589         .notifier_call = acpi_spi_notify,
3590 };
3591 #else
3592 extern struct notifier_block spi_acpi_notifier;
3593 #endif
3594
3595 static int __init spi_init(void)
3596 {
3597         int     status;
3598
3599         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3600         if (!buf) {
3601                 status = -ENOMEM;
3602                 goto err0;
3603         }
3604
3605         status = bus_register(&spi_bus_type);
3606         if (status < 0)
3607                 goto err1;
3608
3609         status = class_register(&spi_master_class);
3610         if (status < 0)
3611                 goto err2;
3612
3613         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3614                 status = class_register(&spi_slave_class);
3615                 if (status < 0)
3616                         goto err3;
3617         }
3618
3619         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3620                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3621         if (IS_ENABLED(CONFIG_ACPI))
3622                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3623
3624         return 0;
3625
3626 err3:
3627         class_unregister(&spi_master_class);
3628 err2:
3629         bus_unregister(&spi_bus_type);
3630 err1:
3631         kfree(buf);
3632         buf = NULL;
3633 err0:
3634         return status;
3635 }
3636
3637 /* board_info is normally registered in arch_initcall(),
3638  * but even essential drivers wait till later
3639  *
3640  * REVISIT only boardinfo really needs static linking. the rest (device and
3641  * driver registration) _could_ be dynamically linked (modular) ... costs
3642  * include needing to have boardinfo data structures be much more public.
3643  */
3644 postcore_initcall(spi_init);
3645