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  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define pr_fmt(fmt)     "%s(): " fmt, __func__
  21
  22 #include <linux/module.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/slab.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/mm.h>
  28 #include <linux/list.h>
  29 #include <linux/device.h>
  30 #include <linux/io.h>
  31 #include <linux/iommu.h>
  32 #include <linux/of.h>
  33
  34 #include <asm/cacheflush.h>
  35
  36 /* bitmap of the page sizes currently supported */
  37 #define GART_IOMMU_PGSIZES      (SZ_4K)
  38
  39 #define GART_REG_BASE           0x24
  40 #define GART_CONFIG             (0x24 - GART_REG_BASE)
  41 #define GART_ENTRY_ADDR         (0x28 - GART_REG_BASE)
  42 #define GART_ENTRY_DATA         (0x2c - GART_REG_BASE)
  43 #define GART_ENTRY_PHYS_ADDR_VALID      (1 << 31)
  44
  45 #define GART_PAGE_SHIFT         12
  46 #define GART_PAGE_SIZE          (1 << GART_PAGE_SHIFT)
  47 #define GART_PAGE_MASK                                          \
  48         (~(GART_PAGE_SIZE - 1) & ~GART_ENTRY_PHYS_ADDR_VALID)
  49
  50 struct gart_client {
  51         struct device           *dev;
  52         struct list_head        list;
  53 };
  54
  55 struct gart_device {
  56         void __iomem            *regs;
  57         u32                     *savedata;
  58         u32                     page_count;     /* total remappable size */
  59         dma_addr_t              iovmm_base;     /* offset to vmm_area */
  60         spinlock_t              pte_lock;       /* for pagetable */
  61         struct list_head        client;
  62         spinlock_t              client_lock;    /* for client list */
  63         struct device           *dev;
  64
  65         struct iommu_device     iommu;          /* IOMMU Core handle */
  66 };
  67
  68 struct gart_domain {
  69         struct iommu_domain domain;             /* generic domain handle */
  70         struct gart_device *gart;               /* link to gart device   */
  71 };
  72
  73 static struct gart_device *gart_handle; /* unique for a system */
  74
  75 static bool gart_debug;
  76
  77 #define GART_PTE(_pfn)                                          \
  78         (GART_ENTRY_PHYS_ADDR_VALID | ((_pfn) << PAGE_SHIFT))
  79
  80 static struct gart_domain *to_gart_domain(struct iommu_domain *dom)
  81 {
  82         return container_of(dom, struct gart_domain, domain);
  83 }
  84
  85 /*
  86  * Any interaction between any block on PPSB and a block on APB or AHB
  87  * must have these read-back to ensure the APB/AHB bus transaction is
  88  * complete before initiating activity on the PPSB block.
  89  */
  90 #define FLUSH_GART_REGS(gart)   ((void)readl((gart)->regs + GART_CONFIG))
  91
  92 #define for_each_gart_pte(gart, iova)                                   \
  93         for (iova = gart->iovmm_base;                                   \
  94              iova < gart->iovmm_base + GART_PAGE_SIZE * gart->page_count; \
  95              iova += GART_PAGE_SIZE)
  96
  97 static inline void gart_set_pte(struct gart_device *gart,
  98                                 unsigned long offs, u32 pte)
  99 {
 100         writel(offs, gart->regs + GART_ENTRY_ADDR);
 101         writel(pte, gart->regs + GART_ENTRY_DATA);
 102
 103         dev_dbg(gart->dev, "%s %08lx:%08x\n",
 104                  pte ? "map" : "unmap", offs, pte & GART_PAGE_MASK);
 105 }
 106
 107 static inline unsigned long gart_read_pte(struct gart_device *gart,
 108                                           unsigned long offs)
 109 {
 110         unsigned long pte;
 111
 112         writel(offs, gart->regs + GART_ENTRY_ADDR);
 113         pte = readl(gart->regs + GART_ENTRY_DATA);
 114
 115         return pte;
 116 }
 117
 118 static void do_gart_setup(struct gart_device *gart, const u32 *data)
 119 {
 120         unsigned long iova;
 121
 122         for_each_gart_pte(gart, iova)
 123                 gart_set_pte(gart, iova, data ? *(data++) : 0);
 124
 125         writel(1, gart->regs + GART_CONFIG);
 126         FLUSH_GART_REGS(gart);
 127 }
 128
 129 #ifdef DEBUG
 130 static void gart_dump_table(struct gart_device *gart)
 131 {
 132         unsigned long iova;
 133         unsigned long flags;
 134
 135         spin_lock_irqsave(&gart->pte_lock, flags);
 136         for_each_gart_pte(gart, iova) {
 137                 unsigned long pte;
 138
 139                 pte = gart_read_pte(gart, iova);
 140
 141                 dev_dbg(gart->dev, "%s %08lx:%08lx\n",
 142                         (GART_ENTRY_PHYS_ADDR_VALID & pte) ? "v" : " ",
 143                         iova, pte & GART_PAGE_MASK);
 144         }
 145         spin_unlock_irqrestore(&gart->pte_lock, flags);
 146 }
 147 #else
 148 static inline void gart_dump_table(struct gart_device *gart)
 149 {
 150 }
 151 #endif
 152
 153 static inline bool gart_iova_range_valid(struct gart_device *gart,
 154                                          unsigned long iova, size_t bytes)
 155 {
 156         unsigned long iova_start, iova_end, gart_start, gart_end;
 157
 158         iova_start = iova;
 159         iova_end = iova_start + bytes - 1;
 160         gart_start = gart->iovmm_base;
 161         gart_end = gart_start + gart->page_count * GART_PAGE_SIZE - 1;
 162
 163         if (iova_start < gart_start)
 164                 return false;
 165         if (iova_end > gart_end)
 166                 return false;
 167         return true;
 168 }
 169
 170 static int gart_iommu_attach_dev(struct iommu_domain *domain,
 171                                  struct device *dev)
 172 {
 173         struct gart_domain *gart_domain = to_gart_domain(domain);
 174         struct gart_device *gart = gart_domain->gart;
 175         struct gart_client *client, *c;
 176         int err = 0;
 177
 178         client = devm_kzalloc(gart->dev, sizeof(*c), GFP_KERNEL);
 179         if (!client)
 180                 return -ENOMEM;
 181         client->dev = dev;
 182
 183         spin_lock(&gart->client_lock);
 184         list_for_each_entry(c, &gart->client, list) {
 185                 if (c->dev == dev) {
 186                         dev_err(gart->dev,
 187                                 "%s is already attached\n", dev_name(dev));
 188                         err = -EINVAL;
 189                         goto fail;
 190                 }
 191         }
 192         list_add(&client->list, &gart->client);
 193         spin_unlock(&gart->client_lock);
 194         dev_dbg(gart->dev, "Attached %s\n", dev_name(dev));
 195         return 0;
 196
 197 fail:
 198         devm_kfree(gart->dev, client);
 199         spin_unlock(&gart->client_lock);
 200         return err;
 201 }
 202
 203 static void gart_iommu_detach_dev(struct iommu_domain *domain,
 204                                   struct device *dev)
 205 {
 206         struct gart_domain *gart_domain = to_gart_domain(domain);
 207         struct gart_device *gart = gart_domain->gart;
 208         struct gart_client *c;
 209
 210         spin_lock(&gart->client_lock);
 211
 212         list_for_each_entry(c, &gart->client, list) {
 213                 if (c->dev == dev) {
 214                         list_del(&c->list);
 215                         devm_kfree(gart->dev, c);
 216                         dev_dbg(gart->dev, "Detached %s\n", dev_name(dev));
 217                         goto out;
 218                 }
 219         }
 220         dev_err(gart->dev, "Couldn't find\n");
 221 out:
 222         spin_unlock(&gart->client_lock);
 223 }
 224
 225 static struct iommu_domain *gart_iommu_domain_alloc(unsigned type)
 226 {
 227         struct gart_domain *gart_domain;
 228         struct gart_device *gart;
 229
 230         if (type != IOMMU_DOMAIN_UNMANAGED)
 231                 return NULL;
 232
 233         gart = gart_handle;
 234         if (!gart)
 235                 return NULL;
 236
 237         gart_domain = kzalloc(sizeof(*gart_domain), GFP_KERNEL);
 238         if (!gart_domain)
 239                 return NULL;
 240
 241         gart_domain->gart = gart;
 242         gart_domain->domain.geometry.aperture_start = gart->iovmm_base;
 243         gart_domain->domain.geometry.aperture_end = gart->iovmm_base +
 244                                         gart->page_count * GART_PAGE_SIZE - 1;
 245         gart_domain->domain.geometry.force_aperture = true;
 246
 247         return &gart_domain->domain;
 248 }
 249
 250 static void gart_iommu_domain_free(struct iommu_domain *domain)
 251 {
 252         struct gart_domain *gart_domain = to_gart_domain(domain);
 253         struct gart_device *gart = gart_domain->gart;
 254
 255         if (gart) {
 256                 spin_lock(&gart->client_lock);
 257                 if (!list_empty(&gart->client)) {
 258                         struct gart_client *c;
 259
 260                         list_for_each_entry(c, &gart->client, list)
 261                                 gart_iommu_detach_dev(domain, c->dev);
 262                 }
 263                 spin_unlock(&gart->client_lock);
 264         }
 265
 266         kfree(gart_domain);
 267 }
 268
 269 static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
 270                           phys_addr_t pa, size_t bytes, int prot)
 271 {
 272         struct gart_domain *gart_domain = to_gart_domain(domain);
 273         struct gart_device *gart = gart_domain->gart;
 274         unsigned long flags;
 275         unsigned long pfn;
 276         unsigned long pte;
 277
 278         if (!gart_iova_range_valid(gart, iova, bytes))
 279                 return -EINVAL;
 280
 281         spin_lock_irqsave(&gart->pte_lock, flags);
 282         pfn = __phys_to_pfn(pa);
 283         if (!pfn_valid(pfn)) {
 284                 dev_err(gart->dev, "Invalid page: %pa\n", &pa);
 285                 spin_unlock_irqrestore(&gart->pte_lock, flags);
 286                 return -EINVAL;
 287         }
 288         if (gart_debug) {
 289                 pte = gart_read_pte(gart, iova);
 290                 if (pte & GART_ENTRY_PHYS_ADDR_VALID) {
 291                         spin_unlock_irqrestore(&gart->pte_lock, flags);
 292                         dev_err(gart->dev, "Page entry is in-use\n");
 293                         return -EBUSY;
 294                 }
 295         }
 296         gart_set_pte(gart, iova, GART_PTE(pfn));
 297         FLUSH_GART_REGS(gart);
 298         spin_unlock_irqrestore(&gart->pte_lock, flags);
 299         return 0;
 300 }
 301
 302 static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 303                                size_t bytes)
 304 {
 305         struct gart_domain *gart_domain = to_gart_domain(domain);
 306         struct gart_device *gart = gart_domain->gart;
 307         unsigned long flags;
 308
 309         if (!gart_iova_range_valid(gart, iova, bytes))
 310                 return 0;
 311
 312         spin_lock_irqsave(&gart->pte_lock, flags);
 313         gart_set_pte(gart, iova, 0);
 314         FLUSH_GART_REGS(gart);
 315         spin_unlock_irqrestore(&gart->pte_lock, flags);
 316         return bytes;
 317 }
 318
 319 static phys_addr_t gart_iommu_iova_to_phys(struct iommu_domain *domain,
 320                                            dma_addr_t iova)
 321 {
 322         struct gart_domain *gart_domain = to_gart_domain(domain);
 323         struct gart_device *gart = gart_domain->gart;
 324         unsigned long pte;
 325         phys_addr_t pa;
 326         unsigned long flags;
 327
 328         if (!gart_iova_range_valid(gart, iova, 0))
 329                 return -EINVAL;
 330
 331         spin_lock_irqsave(&gart->pte_lock, flags);
 332         pte = gart_read_pte(gart, iova);
 333         spin_unlock_irqrestore(&gart->pte_lock, flags);
 334
 335         pa = (pte & GART_PAGE_MASK);
 336         if (!pfn_valid(__phys_to_pfn(pa))) {
 337                 dev_err(gart->dev, "No entry for %08llx:%pa\n",
 338                          (unsigned long long)iova, &pa);
 339                 gart_dump_table(gart);
 340                 return -EINVAL;
 341         }
 342         return pa;
 343 }
 344
 345 static bool gart_iommu_capable(enum iommu_cap cap)
 346 {
 347         return false;
 348 }
 349
 350 static int gart_iommu_add_device(struct device *dev)
 351 {
 352         struct iommu_group *group = iommu_group_get_for_dev(dev);
 353
 354         if (IS_ERR(group))
 355                 return PTR_ERR(group);
 356
 357         iommu_group_put(group);
 358
 359         iommu_device_link(&gart_handle->iommu, dev);
 360
 361         return 0;
 362 }
 363
 364 static void gart_iommu_remove_device(struct device *dev)
 365 {
 366         iommu_group_remove_device(dev);
 367         iommu_device_unlink(&gart_handle->iommu, dev);
 368 }
 369
 370 static const struct iommu_ops gart_iommu_ops = {
 371         .capable        = gart_iommu_capable,
 372         .domain_alloc   = gart_iommu_domain_alloc,
 373         .domain_free    = gart_iommu_domain_free,
 374         .attach_dev     = gart_iommu_attach_dev,
 375         .detach_dev     = gart_iommu_detach_dev,
 376         .add_device     = gart_iommu_add_device,
 377         .remove_device  = gart_iommu_remove_device,
 378         .device_group   = generic_device_group,
 379         .map            = gart_iommu_map,
 380         .unmap          = gart_iommu_unmap,
 381         .iova_to_phys   = gart_iommu_iova_to_phys,
 382         .pgsize_bitmap  = GART_IOMMU_PGSIZES,
 383 };
 384
 385 static int tegra_gart_suspend(struct device *dev)
 386 {
 387         struct gart_device *gart = dev_get_drvdata(dev);
 388         unsigned long iova;
 389         u32 *data = gart->savedata;
 390         unsigned long flags;
 391
 392         spin_lock_irqsave(&gart->pte_lock, flags);
 393         for_each_gart_pte(gart, iova)
 394                 *(data++) = gart_read_pte(gart, iova);
 395         spin_unlock_irqrestore(&gart->pte_lock, flags);
 396         return 0;
 397 }
 398
 399 static int tegra_gart_resume(struct device *dev)
 400 {
 401         struct gart_device *gart = dev_get_drvdata(dev);
 402         unsigned long flags;
 403
 404         spin_lock_irqsave(&gart->pte_lock, flags);
 405         do_gart_setup(gart, gart->savedata);
 406         spin_unlock_irqrestore(&gart->pte_lock, flags);
 407         return 0;
 408 }
 409
 410 static int tegra_gart_probe(struct platform_device *pdev)
 411 {
 412         struct gart_device *gart;
 413         struct resource *res, *res_remap;
 414         void __iomem *gart_regs;
 415         struct device *dev = &pdev->dev;
 416         int ret;
 417
 418         if (gart_handle)
 419                 return -EIO;
 420
 421         BUILD_BUG_ON(PAGE_SHIFT != GART_PAGE_SHIFT);
 422
 423         /* the GART memory aperture is required */
 424         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 425         res_remap = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 426         if (!res || !res_remap) {
 427                 dev_err(dev, "GART memory aperture expected\n");
 428                 return -ENXIO;
 429         }
 430
 431         gart = devm_kzalloc(dev, sizeof(*gart), GFP_KERNEL);
 432         if (!gart) {
 433                 dev_err(dev, "failed to allocate gart_device\n");
 434                 return -ENOMEM;
 435         }
 436
 437         gart_regs = devm_ioremap(dev, res->start, resource_size(res));
 438         if (!gart_regs) {
 439                 dev_err(dev, "failed to remap GART registers\n");
 440                 return -ENXIO;
 441         }
 442
 443         ret = iommu_device_sysfs_add(&gart->iommu, &pdev->dev, NULL,
 444                                      dev_name(&pdev->dev));
 445         if (ret) {
 446                 dev_err(dev, "Failed to register IOMMU in sysfs\n");
 447                 return ret;
 448         }
 449
 450         iommu_device_set_ops(&gart->iommu, &gart_iommu_ops);
 451
 452         ret = iommu_device_register(&gart->iommu);
 453         if (ret) {
 454                 dev_err(dev, "Failed to register IOMMU\n");
 455                 iommu_device_sysfs_remove(&gart->iommu);
 456                 return ret;
 457         }
 458
 459         gart->dev = &pdev->dev;
 460         spin_lock_init(&gart->pte_lock);
 461         spin_lock_init(&gart->client_lock);
 462         INIT_LIST_HEAD(&gart->client);
 463         gart->regs = gart_regs;
 464         gart->iovmm_base = (dma_addr_t)res_remap->start;
 465         gart->page_count = (resource_size(res_remap) >> GART_PAGE_SHIFT);
 466
 467         gart->savedata = vmalloc(array_size(sizeof(u32), gart->page_count));
 468         if (!gart->savedata) {
 469                 dev_err(dev, "failed to allocate context save area\n");
 470                 return -ENOMEM;
 471         }
 472
 473         platform_set_drvdata(pdev, gart);
 474         do_gart_setup(gart, NULL);
 475
 476         gart_handle = gart;
 477
 478         return 0;
 479 }
 480
 481 static int tegra_gart_remove(struct platform_device *pdev)
 482 {
 483         struct gart_device *gart = platform_get_drvdata(pdev);
 484
 485         iommu_device_unregister(&gart->iommu);
 486         iommu_device_sysfs_remove(&gart->iommu);
 487
 488         writel(0, gart->regs + GART_CONFIG);
 489         if (gart->savedata)
 490                 vfree(gart->savedata);
 491         gart_handle = NULL;
 492         return 0;
 493 }
 494
 495 static const struct dev_pm_ops tegra_gart_pm_ops = {
 496         .suspend        = tegra_gart_suspend,
 497         .resume         = tegra_gart_resume,
 498 };
 499
 500 static const struct of_device_id tegra_gart_of_match[] = {
 501         { .compatible = "nvidia,tegra20-gart", },
 502         { },
 503 };
 504 MODULE_DEVICE_TABLE(of, tegra_gart_of_match);
 505
 506 static struct platform_driver tegra_gart_driver = {
 507         .probe          = tegra_gart_probe,
 508         .remove         = tegra_gart_remove,
 509         .driver = {
 510                 .name   = "tegra-gart",
 511                 .pm     = &tegra_gart_pm_ops,
 512                 .of_match_table = tegra_gart_of_match,
 513         },
 514 };
 515
 516 static int tegra_gart_init(void)
 517 {
 518         return platform_driver_register(&tegra_gart_driver);
 519 }
 520
 521 static void __exit tegra_gart_exit(void)
 522 {
 523         platform_driver_unregister(&tegra_gart_driver);
 524 }
 525
 526 subsys_initcall(tegra_gart_init);
 527 module_exit(tegra_gart_exit);
 528 module_param(gart_debug, bool, 0644);
 529
 530 MODULE_PARM_DESC(gart_debug, "Enable GART debugging");
 531 MODULE_DESCRIPTION("IOMMU API for GART in Tegra20");
 532 MODULE_AUTHOR("Hiroshi DOYU <hdoyu@nvidia.com>");
 533 MODULE_ALIAS("platform:tegra-gart");
 534 MODULE_LICENSE("GPL v2");