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