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
  66 static struct gart_device *gart_handle; /* unique for a system */
  67
  68 #define GART_PTE(_pfn)                                          \
  69         (GART_ENTRY_PHYS_ADDR_VALID | ((_pfn) << PAGE_SHIFT))
  70
  71 /*
  72  * Any interaction between any block on PPSB and a block on APB or AHB
  73  * must have these read-back to ensure the APB/AHB bus transaction is
  74  * complete before initiating activity on the PPSB block.
  75  */
  76 #define FLUSH_GART_REGS(gart)   ((void)readl((gart)->regs + GART_CONFIG))
  77
  78 #define for_each_gart_pte(gart, iova)                                   \
  79         for (iova = gart->iovmm_base;                                   \
  80              iova < gart->iovmm_base + GART_PAGE_SIZE * gart->page_count; \
  81              iova += GART_PAGE_SIZE)
  82
  83 static inline void gart_set_pte(struct gart_device *gart,
  84                                 unsigned long offs, u32 pte)
  85 {
  86         writel(offs, gart->regs + GART_ENTRY_ADDR);
  87         writel(pte, gart->regs + GART_ENTRY_DATA);
  88
  89         dev_dbg(gart->dev, "%s %08lx:%08x\n",
  90                  pte ? "map" : "unmap", offs, pte & GART_PAGE_MASK);
  91 }
  92
  93 static inline unsigned long gart_read_pte(struct gart_device *gart,
  94                                           unsigned long offs)
  95 {
  96         unsigned long pte;
  97
  98         writel(offs, gart->regs + GART_ENTRY_ADDR);
  99         pte = readl(gart->regs + GART_ENTRY_DATA);
 100
 101         return pte;
 102 }
 103
 104 static void do_gart_setup(struct gart_device *gart, const u32 *data)
 105 {
 106         unsigned long iova;
 107
 108         for_each_gart_pte(gart, iova)
 109                 gart_set_pte(gart, iova, data ? *(data++) : 0);
 110
 111         writel(1, gart->regs + GART_CONFIG);
 112         FLUSH_GART_REGS(gart);
 113 }
 114
 115 #ifdef DEBUG
 116 static void gart_dump_table(struct gart_device *gart)
 117 {
 118         unsigned long iova;
 119         unsigned long flags;
 120
 121         spin_lock_irqsave(&gart->pte_lock, flags);
 122         for_each_gart_pte(gart, iova) {
 123                 unsigned long pte;
 124
 125                 pte = gart_read_pte(gart, iova);
 126
 127                 dev_dbg(gart->dev, "%s %08lx:%08lx\n",
 128                         (GART_ENTRY_PHYS_ADDR_VALID & pte) ? "v" : " ",
 129                         iova, pte & GART_PAGE_MASK);
 130         }
 131         spin_unlock_irqrestore(&gart->pte_lock, flags);
 132 }
 133 #else
 134 static inline void gart_dump_table(struct gart_device *gart)
 135 {
 136 }
 137 #endif
 138
 139 static inline bool gart_iova_range_valid(struct gart_device *gart,
 140                                          unsigned long iova, size_t bytes)
 141 {
 142         unsigned long iova_start, iova_end, gart_start, gart_end;
 143
 144         iova_start = iova;
 145         iova_end = iova_start + bytes - 1;
 146         gart_start = gart->iovmm_base;
 147         gart_end = gart_start + gart->page_count * GART_PAGE_SIZE - 1;
 148
 149         if (iova_start < gart_start)
 150                 return false;
 151         if (iova_end > gart_end)
 152                 return false;
 153         return true;
 154 }
 155
 156 static int gart_iommu_attach_dev(struct iommu_domain *domain,
 157                                  struct device *dev)
 158 {
 159         struct gart_device *gart;
 160         struct gart_client *client, *c;
 161         int err = 0;
 162
 163         gart = gart_handle;
 164         if (!gart)
 165                 return -EINVAL;
 166         domain->priv = gart;
 167
 168         domain->geometry.aperture_start = gart->iovmm_base;
 169         domain->geometry.aperture_end   = gart->iovmm_base +
 170                                         gart->page_count * GART_PAGE_SIZE - 1;
 171         domain->geometry.force_aperture = true;
 172
 173         client = devm_kzalloc(gart->dev, sizeof(*c), GFP_KERNEL);
 174         if (!client)
 175                 return -ENOMEM;
 176         client->dev = dev;
 177
 178         spin_lock(&gart->client_lock);
 179         list_for_each_entry(c, &gart->client, list) {
 180                 if (c->dev == dev) {
 181                         dev_err(gart->dev,
 182                                 "%s is already attached\n", dev_name(dev));
 183                         err = -EINVAL;
 184                         goto fail;
 185                 }
 186         }
 187         list_add(&client->list, &gart->client);
 188         spin_unlock(&gart->client_lock);
 189         dev_dbg(gart->dev, "Attached %s\n", dev_name(dev));
 190         return 0;
 191
 192 fail:
 193         devm_kfree(gart->dev, client);
 194         spin_unlock(&gart->client_lock);
 195         return err;
 196 }
 197
 198 static void gart_iommu_detach_dev(struct iommu_domain *domain,
 199                                   struct device *dev)
 200 {
 201         struct gart_device *gart = domain->priv;
 202         struct gart_client *c;
 203
 204         spin_lock(&gart->client_lock);
 205
 206         list_for_each_entry(c, &gart->client, list) {
 207                 if (c->dev == dev) {
 208                         list_del(&c->list);
 209                         devm_kfree(gart->dev, c);
 210                         dev_dbg(gart->dev, "Detached %s\n", dev_name(dev));
 211                         goto out;
 212                 }
 213         }
 214         dev_err(gart->dev, "Couldn't find\n");
 215 out:
 216         spin_unlock(&gart->client_lock);
 217 }
 218
 219 static int gart_iommu_domain_init(struct iommu_domain *domain)
 220 {
 221         return 0;
 222 }
 223
 224 static void gart_iommu_domain_destroy(struct iommu_domain *domain)
 225 {
 226         struct gart_device *gart = domain->priv;
 227
 228         if (!gart)
 229                 return;
 230
 231         spin_lock(&gart->client_lock);
 232         if (!list_empty(&gart->client)) {
 233                 struct gart_client *c;
 234
 235                 list_for_each_entry(c, &gart->client, list)
 236                         gart_iommu_detach_dev(domain, c->dev);
 237         }
 238         spin_unlock(&gart->client_lock);
 239         domain->priv = NULL;
 240 }
 241
 242 static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
 243                           phys_addr_t pa, size_t bytes, int prot)
 244 {
 245         struct gart_device *gart = domain->priv;
 246         unsigned long flags;
 247         unsigned long pfn;
 248
 249         if (!gart_iova_range_valid(gart, iova, bytes))
 250                 return -EINVAL;
 251
 252         spin_lock_irqsave(&gart->pte_lock, flags);
 253         pfn = __phys_to_pfn(pa);
 254         if (!pfn_valid(pfn)) {
 255                 dev_err(gart->dev, "Invalid page: %pa\n", &pa);
 256                 spin_unlock_irqrestore(&gart->pte_lock, flags);
 257                 return -EINVAL;
 258         }
 259         gart_set_pte(gart, iova, GART_PTE(pfn));
 260         FLUSH_GART_REGS(gart);
 261         spin_unlock_irqrestore(&gart->pte_lock, flags);
 262         return 0;
 263 }
 264
 265 static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 266                                size_t bytes)
 267 {
 268         struct gart_device *gart = domain->priv;
 269         unsigned long flags;
 270
 271         if (!gart_iova_range_valid(gart, iova, bytes))
 272                 return 0;
 273
 274         spin_lock_irqsave(&gart->pte_lock, flags);
 275         gart_set_pte(gart, iova, 0);
 276         FLUSH_GART_REGS(gart);
 277         spin_unlock_irqrestore(&gart->pte_lock, flags);
 278         return 0;
 279 }
 280
 281 static phys_addr_t gart_iommu_iova_to_phys(struct iommu_domain *domain,
 282                                            dma_addr_t iova)
 283 {
 284         struct gart_device *gart = domain->priv;
 285         unsigned long pte;
 286         phys_addr_t pa;
 287         unsigned long flags;
 288
 289         if (!gart_iova_range_valid(gart, iova, 0))
 290                 return -EINVAL;
 291
 292         spin_lock_irqsave(&gart->pte_lock, flags);
 293         pte = gart_read_pte(gart, iova);
 294         spin_unlock_irqrestore(&gart->pte_lock, flags);
 295
 296         pa = (pte & GART_PAGE_MASK);
 297         if (!pfn_valid(__phys_to_pfn(pa))) {
 298                 dev_err(gart->dev, "No entry for %08llx:%pa\n",
 299                          (unsigned long long)iova, &pa);
 300                 gart_dump_table(gart);
 301                 return -EINVAL;
 302         }
 303         return pa;
 304 }
 305
 306 static int gart_iommu_domain_has_cap(struct iommu_domain *domain,
 307                                      unsigned long cap)
 308 {
 309         return 0;
 310 }
 311
 312 static struct iommu_ops gart_iommu_ops = {
 313         .domain_init    = gart_iommu_domain_init,
 314         .domain_destroy = gart_iommu_domain_destroy,
 315         .attach_dev     = gart_iommu_attach_dev,
 316         .detach_dev     = gart_iommu_detach_dev,
 317         .map            = gart_iommu_map,
 318         .unmap          = gart_iommu_unmap,
 319         .iova_to_phys   = gart_iommu_iova_to_phys,
 320         .domain_has_cap = gart_iommu_domain_has_cap,
 321         .pgsize_bitmap  = GART_IOMMU_PGSIZES,
 322 };
 323
 324 static int tegra_gart_suspend(struct device *dev)
 325 {
 326         struct gart_device *gart = dev_get_drvdata(dev);
 327         unsigned long iova;
 328         u32 *data = gart->savedata;
 329         unsigned long flags;
 330
 331         spin_lock_irqsave(&gart->pte_lock, flags);
 332         for_each_gart_pte(gart, iova)
 333                 *(data++) = gart_read_pte(gart, iova);
 334         spin_unlock_irqrestore(&gart->pte_lock, flags);
 335         return 0;
 336 }
 337
 338 static int tegra_gart_resume(struct device *dev)
 339 {
 340         struct gart_device *gart = dev_get_drvdata(dev);
 341         unsigned long flags;
 342
 343         spin_lock_irqsave(&gart->pte_lock, flags);
 344         do_gart_setup(gart, gart->savedata);
 345         spin_unlock_irqrestore(&gart->pte_lock, flags);
 346         return 0;
 347 }
 348
 349 static int tegra_gart_probe(struct platform_device *pdev)
 350 {
 351         struct gart_device *gart;
 352         struct resource *res, *res_remap;
 353         void __iomem *gart_regs;
 354         struct device *dev = &pdev->dev;
 355
 356         if (gart_handle)
 357                 return -EIO;
 358
 359         BUILD_BUG_ON(PAGE_SHIFT != GART_PAGE_SHIFT);
 360
 361         /* the GART memory aperture is required */
 362         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 363         res_remap = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 364         if (!res || !res_remap) {
 365                 dev_err(dev, "GART memory aperture expected\n");
 366                 return -ENXIO;
 367         }
 368
 369         gart = devm_kzalloc(dev, sizeof(*gart), GFP_KERNEL);
 370         if (!gart) {
 371                 dev_err(dev, "failed to allocate gart_device\n");
 372                 return -ENOMEM;
 373         }
 374
 375         gart_regs = devm_ioremap(dev, res->start, resource_size(res));
 376         if (!gart_regs) {
 377                 dev_err(dev, "failed to remap GART registers\n");
 378                 return -ENXIO;
 379         }
 380
 381         gart->dev = &pdev->dev;
 382         spin_lock_init(&gart->pte_lock);
 383         spin_lock_init(&gart->client_lock);
 384         INIT_LIST_HEAD(&gart->client);
 385         gart->regs = gart_regs;
 386         gart->iovmm_base = (dma_addr_t)res_remap->start;
 387         gart->page_count = (resource_size(res_remap) >> GART_PAGE_SHIFT);
 388
 389         gart->savedata = vmalloc(sizeof(u32) * gart->page_count);
 390         if (!gart->savedata) {
 391                 dev_err(dev, "failed to allocate context save area\n");
 392                 return -ENOMEM;
 393         }
 394
 395         platform_set_drvdata(pdev, gart);
 396         do_gart_setup(gart, NULL);
 397
 398         gart_handle = gart;
 399         bus_set_iommu(&platform_bus_type, &gart_iommu_ops);
 400         return 0;
 401 }
 402
 403 static int tegra_gart_remove(struct platform_device *pdev)
 404 {
 405         struct gart_device *gart = platform_get_drvdata(pdev);
 406
 407         writel(0, gart->regs + GART_CONFIG);
 408         if (gart->savedata)
 409                 vfree(gart->savedata);
 410         gart_handle = NULL;
 411         return 0;
 412 }
 413
 414 static const struct dev_pm_ops tegra_gart_pm_ops = {
 415         .suspend        = tegra_gart_suspend,
 416         .resume         = tegra_gart_resume,
 417 };
 418
 419 static struct of_device_id tegra_gart_of_match[] = {
 420         { .compatible = "nvidia,tegra20-gart", },
 421         { },
 422 };
 423 MODULE_DEVICE_TABLE(of, tegra_gart_of_match);
 424
 425 static struct platform_driver tegra_gart_driver = {
 426         .probe          = tegra_gart_probe,
 427         .remove         = tegra_gart_remove,
 428         .driver = {
 429                 .owner  = THIS_MODULE,
 430                 .name   = "tegra-gart",
 431                 .pm     = &tegra_gart_pm_ops,
 432                 .of_match_table = tegra_gart_of_match,
 433         },
 434 };
 435
 436 static int tegra_gart_init(void)
 437 {
 438         return platform_driver_register(&tegra_gart_driver);
 439 }
 440
 441 static void __exit tegra_gart_exit(void)
 442 {
 443         platform_driver_unregister(&tegra_gart_driver);
 444 }
 445
 446 subsys_initcall(tegra_gart_init);
 447 module_exit(tegra_gart_exit);
 448
 449 MODULE_DESCRIPTION("IOMMU API for GART in Tegra20");
 450 MODULE_AUTHOR("Hiroshi DOYU <hdoyu@nvidia.com>");
 451 MODULE_ALIAS("platform:tegra-gart");
 452 MODULE_LICENSE("GPL v2");