drivers/iommu/tegra-gart.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * IOMMU API for Graphics Address Relocation Table on Tegra20
   4  *
   5  * Copyright (c) 2010-2012, NVIDIA CORPORATION.  All rights reserved.
   6  *
   7  * Author: Hiroshi DOYU <hdoyu@nvidia.com>
   8  */
   9
  10 #define dev_fmt(fmt)    "gart: " fmt
  11
  12 #include <linux/io.h>
  13 #include <linux/iommu.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/slab.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/vmalloc.h>
  19
  20 #include <soc/tegra/mc.h>
  21
  22 #define GART_REG_BASE           0x24
  23 #define GART_CONFIG             (0x24 - GART_REG_BASE)
  24 #define GART_ENTRY_ADDR         (0x28 - GART_REG_BASE)
  25 #define GART_ENTRY_DATA         (0x2c - GART_REG_BASE)
  26
  27 #define GART_ENTRY_PHYS_ADDR_VALID      BIT(31)
  28
  29 #define GART_PAGE_SHIFT         12
  30 #define GART_PAGE_SIZE          (1 << GART_PAGE_SHIFT)
  31 #define GART_PAGE_MASK          GENMASK(30, GART_PAGE_SHIFT)
  32
  33 /* bitmap of the page sizes currently supported */
  34 #define GART_IOMMU_PGSIZES      (GART_PAGE_SIZE)
  35
  36 struct gart_device {
  37         void __iomem            *regs;
  38         u32                     *savedata;
  39         unsigned long           iovmm_base;     /* offset to vmm_area start */
  40         unsigned long           iovmm_end;      /* offset to vmm_area end */
  41         spinlock_t              pte_lock;       /* for pagetable */
  42         spinlock_t              dom_lock;       /* for active domain */
  43         unsigned int            active_devices; /* number of active devices */
  44         struct iommu_domain     *active_domain; /* current active domain */
  45         struct iommu_device     iommu;          /* IOMMU Core handle */
  46         struct device           *dev;
  47 };
  48
  49 static struct gart_device *gart_handle; /* unique for a system */
  50
  51 static bool gart_debug;
  52
  53 /*
  54  * Any interaction between any block on PPSB and a block on APB or AHB
  55  * must have these read-back to ensure the APB/AHB bus transaction is
  56  * complete before initiating activity on the PPSB block.
  57  */
  58 #define FLUSH_GART_REGS(gart)   readl_relaxed((gart)->regs + GART_CONFIG)
  59
  60 #define for_each_gart_pte(gart, iova)                                   \
  61         for (iova = gart->iovmm_base;                                   \
  62              iova < gart->iovmm_end;                                    \
  63              iova += GART_PAGE_SIZE)
  64
  65 static inline void gart_set_pte(struct gart_device *gart,
  66                                 unsigned long iova, unsigned long pte)
  67 {
  68         writel_relaxed(iova, gart->regs + GART_ENTRY_ADDR);
  69         writel_relaxed(pte, gart->regs + GART_ENTRY_DATA);
  70 }
  71
  72 static inline unsigned long gart_read_pte(struct gart_device *gart,
  73                                           unsigned long iova)
  74 {
  75         unsigned long pte;
  76
  77         writel_relaxed(iova, gart->regs + GART_ENTRY_ADDR);
  78         pte = readl_relaxed(gart->regs + GART_ENTRY_DATA);
  79
  80         return pte;
  81 }
  82
  83 static void do_gart_setup(struct gart_device *gart, const u32 *data)
  84 {
  85         unsigned long iova;
  86
  87         for_each_gart_pte(gart, iova)
  88                 gart_set_pte(gart, iova, data ? *(data++) : 0);
  89
  90         writel_relaxed(1, gart->regs + GART_CONFIG);
  91         FLUSH_GART_REGS(gart);
  92 }
  93
  94 static inline bool gart_iova_range_invalid(struct gart_device *gart,
  95                                            unsigned long iova, size_t bytes)
  96 {
  97         return unlikely(iova < gart->iovmm_base || bytes != GART_PAGE_SIZE ||
  98                         iova + bytes > gart->iovmm_end);
  99 }
 100
 101 static inline bool gart_pte_valid(struct gart_device *gart, unsigned long iova)
 102 {
 103         return !!(gart_read_pte(gart, iova) & GART_ENTRY_PHYS_ADDR_VALID);
 104 }
 105
 106 static int gart_iommu_attach_dev(struct iommu_domain *domain,
 107                                  struct device *dev)
 108 {
 109         struct gart_device *gart = gart_handle;
 110         int ret = 0;
 111
 112         spin_lock(&gart->dom_lock);
 113
 114         if (gart->active_domain && gart->active_domain != domain) {
 115                 ret = -EBUSY;
 116         } else if (dev_iommu_priv_get(dev) != domain) {
 117                 dev_iommu_priv_set(dev, domain);
 118                 gart->active_domain = domain;
 119                 gart->active_devices++;
 120         }
 121
 122         spin_unlock(&gart->dom_lock);
 123
 124         return ret;
 125 }
 126
 127 static void gart_iommu_detach_dev(struct iommu_domain *domain,
 128                                   struct device *dev)
 129 {
 130         struct gart_device *gart = gart_handle;
 131
 132         spin_lock(&gart->dom_lock);
 133
 134         if (dev_iommu_priv_get(dev) == domain) {
 135                 dev_iommu_priv_set(dev, NULL);
 136
 137                 if (--gart->active_devices == 0)
 138                         gart->active_domain = NULL;
 139         }
 140
 141         spin_unlock(&gart->dom_lock);
 142 }
 143
 144 static struct iommu_domain *gart_iommu_domain_alloc(unsigned type)
 145 {
 146         struct iommu_domain *domain;
 147
 148         if (type != IOMMU_DOMAIN_UNMANAGED)
 149                 return NULL;
 150
 151         domain = kzalloc(sizeof(*domain), GFP_KERNEL);
 152         if (domain) {
 153                 domain->geometry.aperture_start = gart_handle->iovmm_base;
 154                 domain->geometry.aperture_end = gart_handle->iovmm_end - 1;
 155                 domain->geometry.force_aperture = true;
 156         }
 157
 158         return domain;
 159 }
 160
 161 static void gart_iommu_domain_free(struct iommu_domain *domain)
 162 {
 163         WARN_ON(gart_handle->active_domain == domain);
 164         kfree(domain);
 165 }
 166
 167 static inline int __gart_iommu_map(struct gart_device *gart, unsigned long iova,
 168                                    unsigned long pa)
 169 {
 170         if (unlikely(gart_debug && gart_pte_valid(gart, iova))) {
 171                 dev_err(gart->dev, "Page entry is in-use\n");
 172                 return -EINVAL;
 173         }
 174
 175         gart_set_pte(gart, iova, GART_ENTRY_PHYS_ADDR_VALID | pa);
 176
 177         return 0;
 178 }
 179
 180 static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
 181                           phys_addr_t pa, size_t bytes, int prot, gfp_t gfp)
 182 {
 183         struct gart_device *gart = gart_handle;
 184         int ret;
 185
 186         if (gart_iova_range_invalid(gart, iova, bytes))
 187                 return -EINVAL;
 188
 189         spin_lock(&gart->pte_lock);
 190         ret = __gart_iommu_map(gart, iova, (unsigned long)pa);
 191         spin_unlock(&gart->pte_lock);
 192
 193         return ret;
 194 }
 195
 196 static inline int __gart_iommu_unmap(struct gart_device *gart,
 197                                      unsigned long iova)
 198 {
 199         if (unlikely(gart_debug && !gart_pte_valid(gart, iova))) {
 200                 dev_err(gart->dev, "Page entry is invalid\n");
 201                 return -EINVAL;
 202         }
 203
 204         gart_set_pte(gart, iova, 0);
 205
 206         return 0;
 207 }
 208
 209 static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 210                                size_t bytes, struct iommu_iotlb_gather *gather)
 211 {
 212         struct gart_device *gart = gart_handle;
 213         int err;
 214
 215         if (gart_iova_range_invalid(gart, iova, bytes))
 216                 return 0;
 217
 218         spin_lock(&gart->pte_lock);
 219         err = __gart_iommu_unmap(gart, iova);
 220         spin_unlock(&gart->pte_lock);
 221
 222         return err ? 0 : bytes;
 223 }
 224
 225 static phys_addr_t gart_iommu_iova_to_phys(struct iommu_domain *domain,
 226                                            dma_addr_t iova)
 227 {
 228         struct gart_device *gart = gart_handle;
 229         unsigned long pte;
 230
 231         if (gart_iova_range_invalid(gart, iova, GART_PAGE_SIZE))
 232                 return -EINVAL;
 233
 234         spin_lock(&gart->pte_lock);
 235         pte = gart_read_pte(gart, iova);
 236         spin_unlock(&gart->pte_lock);
 237
 238         return pte & GART_PAGE_MASK;
 239 }
 240
 241 static bool gart_iommu_capable(enum iommu_cap cap)
 242 {
 243         return false;
 244 }
 245
 246 static struct iommu_device *gart_iommu_probe_device(struct device *dev)
 247 {
 248         if (!dev_iommu_fwspec_get(dev))
 249                 return ERR_PTR(-ENODEV);
 250
 251         return &gart_handle->iommu;
 252 }
 253
 254 static void gart_iommu_release_device(struct device *dev)
 255 {
 256 }
 257
 258 static int gart_iommu_of_xlate(struct device *dev,
 259                                struct of_phandle_args *args)
 260 {
 261         return 0;
 262 }
 263
 264 static void gart_iommu_sync_map(struct iommu_domain *domain)
 265 {
 266         FLUSH_GART_REGS(gart_handle);
 267 }
 268
 269 static void gart_iommu_sync(struct iommu_domain *domain,
 270                             struct iommu_iotlb_gather *gather)
 271 {
 272         gart_iommu_sync_map(domain);
 273 }
 274
 275 static const struct iommu_ops gart_iommu_ops = {
 276         .capable        = gart_iommu_capable,
 277         .domain_alloc   = gart_iommu_domain_alloc,
 278         .domain_free    = gart_iommu_domain_free,
 279         .attach_dev     = gart_iommu_attach_dev,
 280         .detach_dev     = gart_iommu_detach_dev,
 281         .probe_device   = gart_iommu_probe_device,
 282         .release_device = gart_iommu_release_device,
 283         .device_group   = generic_device_group,
 284         .map            = gart_iommu_map,
 285         .unmap          = gart_iommu_unmap,
 286         .iova_to_phys   = gart_iommu_iova_to_phys,
 287         .pgsize_bitmap  = GART_IOMMU_PGSIZES,
 288         .of_xlate       = gart_iommu_of_xlate,
 289         .iotlb_sync_map = gart_iommu_sync_map,
 290         .iotlb_sync     = gart_iommu_sync,
 291 };
 292
 293 int tegra_gart_suspend(struct gart_device *gart)
 294 {
 295         u32 *data = gart->savedata;
 296         unsigned long iova;
 297
 298         /*
 299          * All GART users shall be suspended at this point. Disable
 300          * address translation to trap all GART accesses as invalid
 301          * memory accesses.
 302          */
 303         writel_relaxed(0, gart->regs + GART_CONFIG);
 304         FLUSH_GART_REGS(gart);
 305
 306         for_each_gart_pte(gart, iova)
 307                 *(data++) = gart_read_pte(gart, iova);
 308
 309         return 0;
 310 }
 311
 312 int tegra_gart_resume(struct gart_device *gart)
 313 {
 314         do_gart_setup(gart, gart->savedata);
 315
 316         return 0;
 317 }
 318
 319 struct gart_device *tegra_gart_probe(struct device *dev, struct tegra_mc *mc)
 320 {
 321         struct gart_device *gart;
 322         struct resource *res;
 323         int err;
 324
 325         BUILD_BUG_ON(PAGE_SHIFT != GART_PAGE_SHIFT);
 326
 327         /* the GART memory aperture is required */
 328         res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 1);
 329         if (!res) {
 330                 dev_err(dev, "Memory aperture resource unavailable\n");
 331                 return ERR_PTR(-ENXIO);
 332         }
 333
 334         gart = kzalloc(sizeof(*gart), GFP_KERNEL);
 335         if (!gart)
 336                 return ERR_PTR(-ENOMEM);
 337
 338         gart_handle = gart;
 339
 340         gart->dev = dev;
 341         gart->regs = mc->regs + GART_REG_BASE;
 342         gart->iovmm_base = res->start;
 343         gart->iovmm_end = res->end + 1;
 344         spin_lock_init(&gart->pte_lock);
 345         spin_lock_init(&gart->dom_lock);
 346
 347         do_gart_setup(gart, NULL);
 348
 349         err = iommu_device_sysfs_add(&gart->iommu, dev, NULL, "gart");
 350         if (err)
 351                 goto free_gart;
 352
 353         iommu_device_set_ops(&gart->iommu, &gart_iommu_ops);
 354         iommu_device_set_fwnode(&gart->iommu, dev->fwnode);
 355
 356         err = iommu_device_register(&gart->iommu);
 357         if (err)
 358                 goto remove_sysfs;
 359
 360         gart->savedata = vmalloc(resource_size(res) / GART_PAGE_SIZE *
 361                                  sizeof(u32));
 362         if (!gart->savedata) {
 363                 err = -ENOMEM;
 364                 goto unregister_iommu;
 365         }
 366
 367         return gart;
 368
 369 unregister_iommu:
 370         iommu_device_unregister(&gart->iommu);
 371 remove_sysfs:
 372         iommu_device_sysfs_remove(&gart->iommu);
 373 free_gart:
 374         kfree(gart);
 375
 376         return ERR_PTR(err);
 377 }
 378
 379 module_param(gart_debug, bool, 0644);
 380 MODULE_PARM_DESC(gart_debug, "Enable GART debugging");