drivers/iommu/tegra-gart.c

   1 /*
   2  * IOMMU API for GART in Tegra20
   3  *
   4  * Copyright (c) 2010-2012, NVIDIA CORPORATION.  All rights reserved.
   5  *
   6  * Author: Hiroshi DOYU <hdoyu@nvidia.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  20  */
  21
  22 #include <linux/io.h>
  23 #include <linux/iommu.h>
  24 #include <linux/list.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/slab.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/vmalloc.h>
  30
  31 #include <soc/tegra/mc.h>
  32
  33 /* bitmap of the page sizes currently supported */
  34 #define GART_IOMMU_PGSIZES      (SZ_4K)
  35
  36 #define GART_REG_BASE           0x24
  37 #define GART_CONFIG             (0x24 - GART_REG_BASE)
  38 #define GART_ENTRY_ADDR         (0x28 - GART_REG_BASE)
  39 #define GART_ENTRY_DATA         (0x2c - GART_REG_BASE)
  40 #define GART_ENTRY_PHYS_ADDR_VALID      (1 << 31)
  41
  42 #define GART_PAGE_SHIFT         12
  43 #define GART_PAGE_SIZE          (1 << GART_PAGE_SHIFT)
  44 #define GART_PAGE_MASK                                          \
  45         (~(GART_PAGE_SIZE - 1) & ~GART_ENTRY_PHYS_ADDR_VALID)
  46
  47 struct gart_client {
  48         struct device           *dev;
  49         struct list_head        list;
  50 };
  51
  52 struct gart_device {
  53         void __iomem            *regs;
  54         u32                     *savedata;
  55         u32                     page_count;     /* total remappable size */
  56         dma_addr_t              iovmm_base;     /* offset to vmm_area */
  57         spinlock_t              pte_lock;       /* for pagetable */
  58         struct list_head        client;
  59         spinlock_t              client_lock;    /* for client list */
  60         struct device           *dev;
  61
  62         struct iommu_device     iommu;          /* IOMMU Core handle */
  63 };
  64
  65 struct gart_domain {
  66         struct iommu_domain domain;             /* generic domain handle */
  67         struct gart_device *gart;               /* link to gart device   */
  68 };
  69
  70 static struct gart_device *gart_handle; /* unique for a system */
  71
  72 static bool gart_debug;
  73
  74 #define GART_PTE(_pfn)                                          \
  75         (GART_ENTRY_PHYS_ADDR_VALID | ((_pfn) << PAGE_SHIFT))
  76
  77 static struct gart_domain *to_gart_domain(struct iommu_domain *dom)
  78 {
  79         return container_of(dom, struct gart_domain, domain);
  80 }
  81
  82 /*
  83  * Any interaction between any block on PPSB and a block on APB or AHB
  84  * must have these read-back to ensure the APB/AHB bus transaction is
  85  * complete before initiating activity on the PPSB block.
  86  */
  87 #define FLUSH_GART_REGS(gart)   ((void)readl((gart)->regs + GART_CONFIG))
  88
  89 #define for_each_gart_pte(gart, iova)                                   \
  90         for (iova = gart->iovmm_base;                                   \
  91              iova < gart->iovmm_base + GART_PAGE_SIZE * gart->page_count; \
  92              iova += GART_PAGE_SIZE)
  93
  94 static inline void gart_set_pte(struct gart_device *gart,
  95                                 unsigned long offs, u32 pte)
  96 {
  97         writel(offs, gart->regs + GART_ENTRY_ADDR);
  98         writel(pte, gart->regs + GART_ENTRY_DATA);
  99
 100         dev_dbg(gart->dev, "%s %08lx:%08x\n",
 101                  pte ? "map" : "unmap", offs, pte & GART_PAGE_MASK);
 102 }
 103
 104 static inline unsigned long gart_read_pte(struct gart_device *gart,
 105                                           unsigned long offs)
 106 {
 107         unsigned long pte;
 108
 109         writel(offs, gart->regs + GART_ENTRY_ADDR);
 110         pte = readl(gart->regs + GART_ENTRY_DATA);
 111
 112         return pte;
 113 }
 114
 115 static void do_gart_setup(struct gart_device *gart, const u32 *data)
 116 {
 117         unsigned long iova;
 118
 119         for_each_gart_pte(gart, iova)
 120                 gart_set_pte(gart, iova, data ? *(data++) : 0);
 121
 122         writel(1, gart->regs + GART_CONFIG);
 123         FLUSH_GART_REGS(gart);
 124 }
 125
 126 #ifdef DEBUG
 127 static void gart_dump_table(struct gart_device *gart)
 128 {
 129         unsigned long iova;
 130         unsigned long flags;
 131
 132         spin_lock_irqsave(&gart->pte_lock, flags);
 133         for_each_gart_pte(gart, iova) {
 134                 unsigned long pte;
 135
 136                 pte = gart_read_pte(gart, iova);
 137
 138                 dev_dbg(gart->dev, "%s %08lx:%08lx\n",
 139                         (GART_ENTRY_PHYS_ADDR_VALID & pte) ? "v" : " ",
 140                         iova, pte & GART_PAGE_MASK);
 141         }
 142         spin_unlock_irqrestore(&gart->pte_lock, flags);
 143 }
 144 #else
 145 static inline void gart_dump_table(struct gart_device *gart)
 146 {
 147 }
 148 #endif
 149
 150 static inline bool gart_iova_range_valid(struct gart_device *gart,
 151                                          unsigned long iova, size_t bytes)
 152 {
 153         unsigned long iova_start, iova_end, gart_start, gart_end;
 154
 155         iova_start = iova;
 156         iova_end = iova_start + bytes - 1;
 157         gart_start = gart->iovmm_base;
 158         gart_end = gart_start + gart->page_count * GART_PAGE_SIZE - 1;
 159
 160         if (iova_start < gart_start)
 161                 return false;
 162         if (iova_end > gart_end)
 163                 return false;
 164         return true;
 165 }
 166
 167 static int gart_iommu_attach_dev(struct iommu_domain *domain,
 168                                  struct device *dev)
 169 {
 170         struct gart_domain *gart_domain = to_gart_domain(domain);
 171         struct gart_device *gart = gart_domain->gart;
 172         struct gart_client *client, *c;
 173         int err = 0;
 174
 175         client = devm_kzalloc(gart->dev, sizeof(*c), GFP_KERNEL);
 176         if (!client)
 177                 return -ENOMEM;
 178         client->dev = dev;
 179
 180         spin_lock(&gart->client_lock);
 181         list_for_each_entry(c, &gart->client, list) {
 182                 if (c->dev == dev) {
 183                         dev_err(gart->dev,
 184                                 "%s is already attached\n", dev_name(dev));
 185                         err = -EINVAL;
 186                         goto fail;
 187                 }
 188         }
 189         list_add(&client->list, &gart->client);
 190         spin_unlock(&gart->client_lock);
 191         dev_dbg(gart->dev, "Attached %s\n", dev_name(dev));
 192         return 0;
 193
 194 fail:
 195         devm_kfree(gart->dev, client);
 196         spin_unlock(&gart->client_lock);
 197         return err;
 198 }
 199
 200 static void __gart_iommu_detach_dev(struct iommu_domain *domain,
 201                                     struct device *dev)
 202 {
 203         struct gart_domain *gart_domain = to_gart_domain(domain);
 204         struct gart_device *gart = gart_domain->gart;
 205         struct gart_client *c;
 206
 207         list_for_each_entry(c, &gart->client, list) {
 208                 if (c->dev == dev) {
 209                         list_del(&c->list);
 210                         devm_kfree(gart->dev, c);
 211                         dev_dbg(gart->dev, "Detached %s\n", dev_name(dev));
 212                         return;
 213                 }
 214         }
 215
 216         dev_err(gart->dev, "Couldn't find %s to detach\n", dev_name(dev));
 217 }
 218
 219 static void gart_iommu_detach_dev(struct iommu_domain *domain,
 220                                   struct device *dev)
 221 {
 222         struct gart_domain *gart_domain = to_gart_domain(domain);
 223         struct gart_device *gart = gart_domain->gart;
 224
 225         spin_lock(&gart->client_lock);
 226         __gart_iommu_detach_dev(domain, dev);
 227         spin_unlock(&gart->client_lock);
 228 }
 229
 230 static struct iommu_domain *gart_iommu_domain_alloc(unsigned type)
 231 {
 232         struct gart_domain *gart_domain;
 233         struct gart_device *gart;
 234
 235         if (type != IOMMU_DOMAIN_UNMANAGED)
 236                 return NULL;
 237
 238         gart = gart_handle;
 239         if (!gart)
 240                 return NULL;
 241
 242         gart_domain = kzalloc(sizeof(*gart_domain), GFP_KERNEL);
 243         if (!gart_domain)
 244                 return NULL;
 245
 246         gart_domain->gart = gart;
 247         gart_domain->domain.geometry.aperture_start = gart->iovmm_base;
 248         gart_domain->domain.geometry.aperture_end = gart->iovmm_base +
 249                                         gart->page_count * GART_PAGE_SIZE - 1;
 250         gart_domain->domain.geometry.force_aperture = true;
 251
 252         return &gart_domain->domain;
 253 }
 254
 255 static void gart_iommu_domain_free(struct iommu_domain *domain)
 256 {
 257         struct gart_domain *gart_domain = to_gart_domain(domain);
 258         struct gart_device *gart = gart_domain->gart;
 259
 260         if (gart) {
 261                 spin_lock(&gart->client_lock);
 262                 if (!list_empty(&gart->client)) {
 263                         struct gart_client *c;
 264
 265                         list_for_each_entry(c, &gart->client, list)
 266                                 __gart_iommu_detach_dev(domain, c->dev);
 267                 }
 268                 spin_unlock(&gart->client_lock);
 269         }
 270
 271         kfree(gart_domain);
 272 }
 273
 274 static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
 275                           phys_addr_t pa, size_t bytes, int prot)
 276 {
 277         struct gart_domain *gart_domain = to_gart_domain(domain);
 278         struct gart_device *gart = gart_domain->gart;
 279         unsigned long flags;
 280         unsigned long pfn;
 281         unsigned long pte;
 282
 283         if (!gart_iova_range_valid(gart, iova, bytes))
 284                 return -EINVAL;
 285
 286         spin_lock_irqsave(&gart->pte_lock, flags);
 287         pfn = __phys_to_pfn(pa);
 288         if (!pfn_valid(pfn)) {
 289                 dev_err(gart->dev, "Invalid page: %pa\n", &pa);
 290                 spin_unlock_irqrestore(&gart->pte_lock, flags);
 291                 return -EINVAL;
 292         }
 293         if (gart_debug) {
 294                 pte = gart_read_pte(gart, iova);
 295                 if (pte & GART_ENTRY_PHYS_ADDR_VALID) {
 296                         spin_unlock_irqrestore(&gart->pte_lock, flags);
 297                         dev_err(gart->dev, "Page entry is in-use\n");
 298                         return -EBUSY;
 299                 }
 300         }
 301         gart_set_pte(gart, iova, GART_PTE(pfn));
 302         spin_unlock_irqrestore(&gart->pte_lock, flags);
 303         return 0;
 304 }
 305
 306 static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 307                                size_t bytes)
 308 {
 309         struct gart_domain *gart_domain = to_gart_domain(domain);
 310         struct gart_device *gart = gart_domain->gart;
 311         unsigned long flags;
 312
 313         if (!gart_iova_range_valid(gart, iova, bytes))
 314                 return 0;
 315
 316         spin_lock_irqsave(&gart->pte_lock, flags);
 317         gart_set_pte(gart, iova, 0);
 318         spin_unlock_irqrestore(&gart->pte_lock, flags);
 319         return bytes;
 320 }
 321
 322 static phys_addr_t gart_iommu_iova_to_phys(struct iommu_domain *domain,
 323                                            dma_addr_t iova)
 324 {
 325         struct gart_domain *gart_domain = to_gart_domain(domain);
 326         struct gart_device *gart = gart_domain->gart;
 327         unsigned long pte;
 328         phys_addr_t pa;
 329         unsigned long flags;
 330
 331         if (!gart_iova_range_valid(gart, iova, 0))
 332                 return -EINVAL;
 333
 334         spin_lock_irqsave(&gart->pte_lock, flags);
 335         pte = gart_read_pte(gart, iova);
 336         spin_unlock_irqrestore(&gart->pte_lock, flags);
 337
 338         pa = (pte & GART_PAGE_MASK);
 339         if (!pfn_valid(__phys_to_pfn(pa))) {
 340                 dev_err(gart->dev, "No entry for %08llx:%pa\n",
 341                          (unsigned long long)iova, &pa);
 342                 gart_dump_table(gart);
 343                 return -EINVAL;
 344         }
 345         return pa;
 346 }
 347
 348 static bool gart_iommu_capable(enum iommu_cap cap)
 349 {
 350         return false;
 351 }
 352
 353 static int gart_iommu_add_device(struct device *dev)
 354 {
 355         struct iommu_group *group;
 356
 357         if (!dev->iommu_fwspec)
 358                 return -ENODEV;
 359
 360         group = iommu_group_get_for_dev(dev);
 361         if (IS_ERR(group))
 362                 return PTR_ERR(group);
 363
 364         iommu_group_put(group);
 365
 366         iommu_device_link(&gart_handle->iommu, dev);
 367
 368         return 0;
 369 }
 370
 371 static void gart_iommu_remove_device(struct device *dev)
 372 {
 373         iommu_group_remove_device(dev);
 374         iommu_device_unlink(&gart_handle->iommu, dev);
 375 }
 376
 377 static int gart_iommu_of_xlate(struct device *dev,
 378                                struct of_phandle_args *args)
 379 {
 380         return 0;
 381 }
 382
 383 static void gart_iommu_sync(struct iommu_domain *domain)
 384 {
 385         struct gart_domain *gart_domain = to_gart_domain(domain);
 386         struct gart_device *gart = gart_domain->gart;
 387
 388         FLUSH_GART_REGS(gart);
 389 }
 390
 391 static const struct iommu_ops gart_iommu_ops = {
 392         .capable        = gart_iommu_capable,
 393         .domain_alloc   = gart_iommu_domain_alloc,
 394         .domain_free    = gart_iommu_domain_free,
 395         .attach_dev     = gart_iommu_attach_dev,
 396         .detach_dev     = gart_iommu_detach_dev,
 397         .add_device     = gart_iommu_add_device,
 398         .remove_device  = gart_iommu_remove_device,
 399         .device_group   = generic_device_group,
 400         .map            = gart_iommu_map,
 401         .unmap          = gart_iommu_unmap,
 402         .iova_to_phys   = gart_iommu_iova_to_phys,
 403         .pgsize_bitmap  = GART_IOMMU_PGSIZES,
 404         .of_xlate       = gart_iommu_of_xlate,
 405         .iotlb_sync_map = gart_iommu_sync,
 406         .iotlb_sync     = gart_iommu_sync,
 407 };
 408
 409 int tegra_gart_suspend(struct gart_device *gart)
 410 {
 411         unsigned long iova;
 412         u32 *data = gart->savedata;
 413         unsigned long flags;
 414
 415         spin_lock_irqsave(&gart->pte_lock, flags);
 416         for_each_gart_pte(gart, iova)
 417                 *(data++) = gart_read_pte(gart, iova);
 418         spin_unlock_irqrestore(&gart->pte_lock, flags);
 419         return 0;
 420 }
 421
 422 int tegra_gart_resume(struct gart_device *gart)
 423 {
 424         unsigned long flags;
 425
 426         spin_lock_irqsave(&gart->pte_lock, flags);
 427         do_gart_setup(gart, gart->savedata);
 428         spin_unlock_irqrestore(&gart->pte_lock, flags);
 429         return 0;
 430 }
 431
 432 struct gart_device *tegra_gart_probe(struct device *dev, struct tegra_mc *mc)
 433 {
 434         struct gart_device *gart;
 435         struct resource *res_remap;
 436         void __iomem *gart_regs;
 437         int ret;
 438
 439         BUILD_BUG_ON(PAGE_SHIFT != GART_PAGE_SHIFT);
 440
 441         /* the GART memory aperture is required */
 442         res_remap = platform_get_resource(to_platform_device(dev),
 443                                           IORESOURCE_MEM, 1);
 444         if (!res_remap) {
 445                 dev_err(dev, "GART memory aperture expected\n");
 446                 return ERR_PTR(-ENXIO);
 447         }
 448
 449         gart = devm_kzalloc(dev, sizeof(*gart), GFP_KERNEL);
 450         if (!gart) {
 451                 dev_err(dev, "failed to allocate gart_device\n");
 452                 return ERR_PTR(-ENOMEM);
 453         }
 454
 455         ret = iommu_device_sysfs_add(&gart->iommu, dev, NULL, "gart");
 456         if (ret) {
 457                 dev_err(dev, "Failed to register IOMMU in sysfs\n");
 458                 return ERR_PTR(ret);
 459         }
 460
 461         iommu_device_set_ops(&gart->iommu, &gart_iommu_ops);
 462         iommu_device_set_fwnode(&gart->iommu, dev->fwnode);
 463
 464         ret = iommu_device_register(&gart->iommu);
 465         if (ret) {
 466                 dev_err(dev, "Failed to register IOMMU\n");
 467                 goto remove_sysfs;
 468         }
 469
 470         gart->dev = dev;
 471         gart_regs = mc->regs + GART_REG_BASE;
 472         spin_lock_init(&gart->pte_lock);
 473         spin_lock_init(&gart->client_lock);
 474         INIT_LIST_HEAD(&gart->client);
 475         gart->regs = gart_regs;
 476         gart->iovmm_base = (dma_addr_t)res_remap->start;
 477         gart->page_count = (resource_size(res_remap) >> GART_PAGE_SHIFT);
 478
 479         gart->savedata = vmalloc(array_size(sizeof(u32), gart->page_count));
 480         if (!gart->savedata) {
 481                 dev_err(dev, "failed to allocate context save area\n");
 482                 ret = -ENOMEM;
 483                 goto unregister_iommu;
 484         }
 485
 486         do_gart_setup(gart, NULL);
 487
 488         gart_handle = gart;
 489
 490         return gart;
 491
 492 unregister_iommu:
 493         iommu_device_unregister(&gart->iommu);
 494 remove_sysfs:
 495         iommu_device_sysfs_remove(&gart->iommu);
 496
 497         return ERR_PTR(ret);
 498 }
 499
 500 module_param(gart_debug, bool, 0644);
 501 MODULE_PARM_DESC(gart_debug, "Enable GART debugging");