drivers/char/tpm/tpm_crb.c

   1 /*
   2  * Copyright (C) 2014 Intel Corporation
   3  *
   4  * Authors:
   5  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
   6  *
   7  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
   8  *
   9  * This device driver implements the TPM interface as defined in
  10  * the TCG CRB 2.0 TPM specification.
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; version 2
  15  * of the License.
  16  */
  17
  18 #include <linux/acpi.h>
  19 #include <linux/highmem.h>
  20 #include <linux/rculist.h>
  21 #include <linux/module.h>
  22 #include "tpm.h"
  23
  24 #define ACPI_SIG_TPM2 "TPM2"
  25
  26 static const u8 CRB_ACPI_START_UUID[] = {
  27         /* 0000 */ 0xAB, 0x6C, 0xBF, 0x6B, 0x63, 0x54, 0x14, 0x47,
  28         /* 0008 */ 0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4
  29 };
  30
  31 enum crb_defaults {
  32         CRB_ACPI_START_REVISION_ID = 1,
  33         CRB_ACPI_START_INDEX = 1,
  34 };
  35
  36 enum crb_ctrl_req {
  37         CRB_CTRL_REQ_CMD_READY  = BIT(0),
  38         CRB_CTRL_REQ_GO_IDLE    = BIT(1),
  39 };
  40
  41 enum crb_ctrl_sts {
  42         CRB_CTRL_STS_ERROR      = BIT(0),
  43         CRB_CTRL_STS_TPM_IDLE   = BIT(1),
  44 };
  45
  46 enum crb_start {
  47         CRB_START_INVOKE        = BIT(0),
  48 };
  49
  50 enum crb_cancel {
  51         CRB_CANCEL_INVOKE       = BIT(0),
  52 };
  53
  54 struct crb_control_area {
  55         u32 req;
  56         u32 sts;
  57         u32 cancel;
  58         u32 start;
  59         u32 int_enable;
  60         u32 int_sts;
  61         u32 cmd_size;
  62         u32 cmd_pa_low;
  63         u32 cmd_pa_high;
  64         u32 rsp_size;
  65         u64 rsp_pa;
  66 } __packed;
  67
  68 enum crb_status {
  69         CRB_DRV_STS_COMPLETE    = BIT(0),
  70 };
  71
  72 enum crb_flags {
  73         CRB_FL_ACPI_START       = BIT(0),
  74         CRB_FL_CRB_START        = BIT(1),
  75 };
  76
  77 struct crb_priv {
  78         unsigned int flags;
  79         void __iomem *iobase;
  80         struct crb_control_area __iomem *cca;
  81         u8 __iomem *cmd;
  82         u8 __iomem *rsp;
  83 };
  84
  85 static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
  86
  87 static u8 crb_status(struct tpm_chip *chip)
  88 {
  89         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
  90         u8 sts = 0;
  91
  92         if ((ioread32(&priv->cca->start) & CRB_START_INVOKE) !=
  93             CRB_START_INVOKE)
  94                 sts |= CRB_DRV_STS_COMPLETE;
  95
  96         return sts;
  97 }
  98
  99 static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 100 {
 101         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 102         unsigned int expected;
 103
 104         /* sanity check */
 105         if (count < 6)
 106                 return -EIO;
 107
 108         if (ioread32(&priv->cca->sts) & CRB_CTRL_STS_ERROR)
 109                 return -EIO;
 110
 111         memcpy_fromio(buf, priv->rsp, 6);
 112         expected = be32_to_cpup((__be32 *) &buf[2]);
 113
 114         if (expected > count)
 115                 return -EIO;
 116
 117         memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
 118
 119         return expected;
 120 }
 121
 122 static int crb_do_acpi_start(struct tpm_chip *chip)
 123 {
 124         union acpi_object *obj;
 125         int rc;
 126
 127         obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
 128                                 CRB_ACPI_START_UUID,
 129                                 CRB_ACPI_START_REVISION_ID,
 130                                 CRB_ACPI_START_INDEX,
 131                                 NULL);
 132         if (!obj)
 133                 return -ENXIO;
 134         rc = obj->integer.value == 0 ? 0 : -ENXIO;
 135         ACPI_FREE(obj);
 136         return rc;
 137 }
 138
 139 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 140 {
 141         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 142         int rc = 0;
 143
 144         /* Zero the cancel register so that the next command will not get
 145          * canceled.
 146          */
 147         iowrite32(0, &priv->cca->cancel);
 148
 149         if (len > ioread32(&priv->cca->cmd_size)) {
 150                 dev_err(&chip->dev,
 151                         "invalid command count value %x %zx\n",
 152                         (unsigned int) len,
 153                         (size_t) ioread32(&priv->cca->cmd_size));
 154                 return -E2BIG;
 155         }
 156
 157         memcpy_toio(priv->cmd, buf, len);
 158
 159         /* Make sure that cmd is populated before issuing start. */
 160         wmb();
 161
 162         if (priv->flags & CRB_FL_CRB_START)
 163                 iowrite32(cpu_to_le32(CRB_START_INVOKE), &priv->cca->start);
 164
 165         if (priv->flags & CRB_FL_ACPI_START)
 166                 rc = crb_do_acpi_start(chip);
 167
 168         return rc;
 169 }
 170
 171 static void crb_cancel(struct tpm_chip *chip)
 172 {
 173         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 174
 175         iowrite32(cpu_to_le32(CRB_CANCEL_INVOKE), &priv->cca->cancel);
 176
 177         if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
 178                 dev_err(&chip->dev, "ACPI Start failed\n");
 179 }
 180
 181 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
 182 {
 183         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 184         u32 cancel = ioread32(&priv->cca->cancel);
 185
 186         return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
 187 }
 188
 189 static const struct tpm_class_ops tpm_crb = {
 190         .flags = TPM_OPS_AUTO_STARTUP,
 191         .status = crb_status,
 192         .recv = crb_recv,
 193         .send = crb_send,
 194         .cancel = crb_cancel,
 195         .req_canceled = crb_req_canceled,
 196         .req_complete_mask = CRB_DRV_STS_COMPLETE,
 197         .req_complete_val = CRB_DRV_STS_COMPLETE,
 198 };
 199
 200 static int crb_init(struct acpi_device *device, struct crb_priv *priv)
 201 {
 202         struct tpm_chip *chip;
 203
 204         chip = tpmm_chip_alloc(&device->dev, &tpm_crb);
 205         if (IS_ERR(chip))
 206                 return PTR_ERR(chip);
 207
 208         dev_set_drvdata(&chip->dev, priv);
 209         chip->acpi_dev_handle = device->handle;
 210         chip->flags = TPM_CHIP_FLAG_TPM2;
 211
 212         return tpm_chip_register(chip);
 213 }
 214
 215 static int crb_check_resource(struct acpi_resource *ares, void *data)
 216 {
 217         struct resource *io_res = data;
 218         struct resource res;
 219
 220         if (acpi_dev_resource_memory(ares, &res)) {
 221                 *io_res = res;
 222                 io_res->name = NULL;
 223         }
 224
 225         return 1;
 226 }
 227
 228 static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
 229                                  struct resource *io_res, u64 start, u32 size)
 230 {
 231         struct resource new_res = {
 232                 .start  = start,
 233                 .end    = start + size - 1,
 234                 .flags  = IORESOURCE_MEM,
 235         };
 236
 237         /* Detect a 64 bit address on a 32 bit system */
 238         if (start != new_res.start)
 239                 return (void __iomem *) ERR_PTR(-EINVAL);
 240
 241         if (!resource_contains(io_res, &new_res))
 242                 return devm_ioremap_resource(dev, &new_res);
 243
 244         return priv->iobase + (new_res.start - io_res->start);
 245 }
 246
 247 static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
 248                       struct acpi_table_tpm2 *buf)
 249 {
 250         struct list_head resources;
 251         struct resource io_res;
 252         struct device *dev = &device->dev;
 253         u64 cmd_pa;
 254         u32 cmd_size;
 255         u64 rsp_pa;
 256         u32 rsp_size;
 257         int ret;
 258
 259         INIT_LIST_HEAD(&resources);
 260         ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
 261                                      &io_res);
 262         if (ret < 0)
 263                 return ret;
 264         acpi_dev_free_resource_list(&resources);
 265
 266         if (resource_type(&io_res) != IORESOURCE_MEM) {
 267                 dev_err(dev,
 268                         FW_BUG "TPM2 ACPI table does not define a memory resource\n");
 269                 return -EINVAL;
 270         }
 271
 272         priv->iobase = devm_ioremap_resource(dev, &io_res);
 273         if (IS_ERR(priv->iobase))
 274                 return PTR_ERR(priv->iobase);
 275
 276         priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
 277                                 sizeof(struct crb_control_area));
 278         if (IS_ERR(priv->cca))
 279                 return PTR_ERR(priv->cca);
 280
 281         cmd_pa = ((u64) ioread32(&priv->cca->cmd_pa_high) << 32) |
 282                   (u64) ioread32(&priv->cca->cmd_pa_low);
 283         cmd_size = ioread32(&priv->cca->cmd_size);
 284         priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
 285         if (IS_ERR(priv->cmd))
 286                 return PTR_ERR(priv->cmd);
 287
 288         memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
 289         rsp_pa = le64_to_cpu(rsp_pa);
 290         rsp_size = ioread32(&priv->cca->rsp_size);
 291
 292         if (cmd_pa != rsp_pa) {
 293                 priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
 294                 return PTR_ERR_OR_ZERO(priv->rsp);
 295         }
 296
 297         /* According to the PTP specification, overlapping command and response
 298          * buffer sizes must be identical.
 299          */
 300         if (cmd_size != rsp_size) {
 301                 dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
 302                 return -EINVAL;
 303         }
 304
 305         priv->rsp = priv->cmd;
 306         return 0;
 307 }
 308
 309 static int crb_acpi_add(struct acpi_device *device)
 310 {
 311         struct acpi_table_tpm2 *buf;
 312         struct crb_priv *priv;
 313         struct device *dev = &device->dev;
 314         acpi_status status;
 315         u32 sm;
 316         int rc;
 317
 318         status = acpi_get_table(ACPI_SIG_TPM2, 1,
 319                                 (struct acpi_table_header **) &buf);
 320         if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
 321                 dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 322                 return -EINVAL;
 323         }
 324
 325         /* Should the FIFO driver handle this? */
 326         sm = buf->start_method;
 327         if (sm == ACPI_TPM2_MEMORY_MAPPED)
 328                 return -ENODEV;
 329
 330         priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
 331         if (!priv)
 332                 return -ENOMEM;
 333
 334         /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 335          * report only ACPI start but in practice seems to require both
 336          * ACPI start and CRB start.
 337          */
 338         if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
 339             !strcmp(acpi_device_hid(device), "MSFT0101"))
 340                 priv->flags |= CRB_FL_CRB_START;
 341
 342         if (sm == ACPI_TPM2_START_METHOD ||
 343             sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
 344                 priv->flags |= CRB_FL_ACPI_START;
 345
 346         rc = crb_map_io(device, priv, buf);
 347         if (rc)
 348                 return rc;
 349
 350         return crb_init(device, priv);
 351 }
 352
 353 static int crb_acpi_remove(struct acpi_device *device)
 354 {
 355         struct device *dev = &device->dev;
 356         struct tpm_chip *chip = dev_get_drvdata(dev);
 357
 358         tpm_chip_unregister(chip);
 359
 360         return 0;
 361 }
 362
 363 static struct acpi_device_id crb_device_ids[] = {
 364         {"MSFT0101", 0},
 365         {"", 0},
 366 };
 367 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
 368
 369 static struct acpi_driver crb_acpi_driver = {
 370         .name = "tpm_crb",
 371         .ids = crb_device_ids,
 372         .ops = {
 373                 .add = crb_acpi_add,
 374                 .remove = crb_acpi_remove,
 375         },
 376         .drv = {
 377                 .pm = &crb_pm,
 378         },
 379 };
 380
 381 module_acpi_driver(crb_acpi_driver);
 382 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 383 MODULE_DESCRIPTION("TPM2 Driver");
 384 MODULE_VERSION("0.1");
 385 MODULE_LICENSE("GPL");