root/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c

DEFINITIONS

1. gk20a_instobj_target
2. gk20a_instobj_page
3. gk20a_instobj_addr
4. gk20a_instobj_size
5. gk20a_instobj_iommu_recycle_vaddr
6. gk20a_instmem_vaddr_gc
7. gk20a_instobj_acquire_dma
8. gk20a_instobj_acquire_iommu
9. gk20a_instobj_release_dma
10. gk20a_instobj_release_iommu
11. gk20a_instobj_rd32
12. gk20a_instobj_wr32
13. gk20a_instobj_map
14. gk20a_instobj_dtor_dma
15. gk20a_instobj_dtor_iommu
16. gk20a_instobj_ctor_dma
17. gk20a_instobj_ctor_iommu
18. gk20a_instobj_new
19. gk20a_instmem_dtor
20. gk20a_instmem_new

   1 /*
   2  * Copyright (c) 2015, NVIDIA CORPORATION. All rights reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  19  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  20  * DEALINGS IN THE SOFTWARE.
  21  */
  22 
  23 /*
  24  * GK20A does not have dedicated video memory, and to accurately represent this
  25  * fact Nouveau will not create a RAM device for it. Therefore its instmem
  26  * implementation must be done directly on top of system memory, while
  27  * preserving coherency for read and write operations.
  28  *
  29  * Instmem can be allocated through two means:
  30  * 1) If an IOMMU unit has been probed, the IOMMU API is used to make memory
  31  *    pages contiguous to the GPU. This is the preferred way.
  32  * 2) If no IOMMU unit is probed, the DMA API is used to allocate physically
  33  *    contiguous memory.
  34  *
  35  * In both cases CPU read and writes are performed by creating a write-combined
  36  * mapping. The GPU L2 cache must thus be flushed/invalidated when required. To
  37  * be conservative we do this every time we acquire or release an instobj, but
  38  * ideally L2 management should be handled at a higher level.
  39  *
  40  * To improve performance, CPU mappings are not removed upon instobj release.
  41  * Instead they are placed into a LRU list to be recycled when the mapped space
  42  * goes beyond a certain threshold. At the moment this limit is 1MB.
  43  */
  44 #include "priv.h"
  45 
  46 #include <core/memory.h>
  47 #include <core/tegra.h>
  48 #include <subdev/ltc.h>
  49 #include <subdev/mmu.h>
  50 
  51 struct gk20a_instobj {
  52         struct nvkm_memory memory;
  53         struct nvkm_mm_node *mn;
  54         struct gk20a_instmem *imem;
  55 
  56         /* CPU mapping */
  57         u32 *vaddr;
  58 };
  59 #define gk20a_instobj(p) container_of((p), struct gk20a_instobj, memory)
  60 
  61 /*
  62  * Used for objects allocated using the DMA API
  63  */
  64 struct gk20a_instobj_dma {
  65         struct gk20a_instobj base;
  66 
  67         dma_addr_t handle;
  68         struct nvkm_mm_node r;
  69 };
  70 #define gk20a_instobj_dma(p) \
  71         container_of(gk20a_instobj(p), struct gk20a_instobj_dma, base)
  72 
  73 /*
  74  * Used for objects flattened using the IOMMU API
  75  */
  76 struct gk20a_instobj_iommu {
  77         struct gk20a_instobj base;
  78 
  79         /* to link into gk20a_instmem::vaddr_lru */
  80         struct list_head vaddr_node;
  81         /* how many clients are using vaddr? */
  82         u32 use_cpt;
  83 
  84         /* will point to the higher half of pages */
  85         dma_addr_t *dma_addrs;
  86         /* array of base.mem->size pages (+ dma_addr_ts) */
  87         struct page *pages[];
  88 };
  89 #define gk20a_instobj_iommu(p) \
  90         container_of(gk20a_instobj(p), struct gk20a_instobj_iommu, base)
  91 
  92 struct gk20a_instmem {
  93         struct nvkm_instmem base;
  94 
  95         /* protects vaddr_* and gk20a_instobj::vaddr* */
  96         struct mutex lock;
  97 
  98         /* CPU mappings LRU */
  99         unsigned int vaddr_use;
 100         unsigned int vaddr_max;
 101         struct list_head vaddr_lru;
 102 
 103         /* Only used if IOMMU if present */
 104         struct mutex *mm_mutex;
 105         struct nvkm_mm *mm;
 106         struct iommu_domain *domain;
 107         unsigned long iommu_pgshift;
 108         u16 iommu_bit;
 109 
 110         /* Only used by DMA API */
 111         unsigned long attrs;
 112 };
 113 #define gk20a_instmem(p) container_of((p), struct gk20a_instmem, base)
 114 
 115 static enum nvkm_memory_target
 116 gk20a_instobj_target(struct nvkm_memory *memory)
 117 {
 118         return NVKM_MEM_TARGET_NCOH;
 119 }
 120 
 121 static u8
 122 gk20a_instobj_page(struct nvkm_memory *memory)
 123 {
 124         return 12;
 125 }
 126 
 127 static u64
 128 gk20a_instobj_addr(struct nvkm_memory *memory)
 129 {
 130         return (u64)gk20a_instobj(memory)->mn->offset << 12;
 131 }
 132 
 133 static u64
 134 gk20a_instobj_size(struct nvkm_memory *memory)
 135 {
 136         return (u64)gk20a_instobj(memory)->mn->length << 12;
 137 }
 138 
 139 /*
 140  * Recycle the vaddr of obj. Must be called with gk20a_instmem::lock held.
 141  */
 142 static void
 143 gk20a_instobj_iommu_recycle_vaddr(struct gk20a_instobj_iommu *obj)
 144 {
 145         struct gk20a_instmem *imem = obj->base.imem;
 146         /* there should not be any user left... */
 147         WARN_ON(obj->use_cpt);
 148         list_del(&obj->vaddr_node);
 149         vunmap(obj->base.vaddr);
 150         obj->base.vaddr = NULL;
 151         imem->vaddr_use -= nvkm_memory_size(&obj->base.memory);
 152         nvkm_debug(&imem->base.subdev, "vaddr used: %x/%x\n", imem->vaddr_use,
 153                    imem->vaddr_max);
 154 }
 155 
 156 /*
 157  * Must be called while holding gk20a_instmem::lock
 158  */
 159 static void
 160 gk20a_instmem_vaddr_gc(struct gk20a_instmem *imem, const u64 size)
 161 {
 162         while (imem->vaddr_use + size > imem->vaddr_max) {
 163                 /* no candidate that can be unmapped, abort... */
 164                 if (list_empty(&imem->vaddr_lru))
 165                         break;
 166 
 167                 gk20a_instobj_iommu_recycle_vaddr(
 168                                 list_first_entry(&imem->vaddr_lru,
 169                                 struct gk20a_instobj_iommu, vaddr_node));
 170         }
 171 }
 172 
 173 static void __iomem *
 174 gk20a_instobj_acquire_dma(struct nvkm_memory *memory)
 175 {
 176         struct gk20a_instobj *node = gk20a_instobj(memory);
 177         struct gk20a_instmem *imem = node->imem;
 178         struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
 179 
 180         nvkm_ltc_flush(ltc);
 181 
 182         return node->vaddr;
 183 }
 184 
 185 static void __iomem *
 186 gk20a_instobj_acquire_iommu(struct nvkm_memory *memory)
 187 {
 188         struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
 189         struct gk20a_instmem *imem = node->base.imem;
 190         struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
 191         const u64 size = nvkm_memory_size(memory);
 192 
 193         nvkm_ltc_flush(ltc);
 194 
 195         mutex_lock(&imem->lock);
 196 
 197         if (node->base.vaddr) {
 198                 if (!node->use_cpt) {
 199                         /* remove from LRU list since mapping in use again */
 200                         list_del(&node->vaddr_node);
 201                 }
 202                 goto out;
 203         }
 204 
 205         /* try to free some address space if we reached the limit */
 206         gk20a_instmem_vaddr_gc(imem, size);
 207 
 208         /* map the pages */
 209         node->base.vaddr = vmap(node->pages, size >> PAGE_SHIFT, VM_MAP,
 210                                 pgprot_writecombine(PAGE_KERNEL));
 211         if (!node->base.vaddr) {
 212                 nvkm_error(&imem->base.subdev, "cannot map instobj - "
 213                            "this is not going to end well...\n");
 214                 goto out;
 215         }
 216 
 217         imem->vaddr_use += size;
 218         nvkm_debug(&imem->base.subdev, "vaddr used: %x/%x\n",
 219                    imem->vaddr_use, imem->vaddr_max);
 220 
 221 out:
 222         node->use_cpt++;
 223         mutex_unlock(&imem->lock);
 224 
 225         return node->base.vaddr;
 226 }
 227 
 228 static void
 229 gk20a_instobj_release_dma(struct nvkm_memory *memory)
 230 {
 231         struct gk20a_instobj *node = gk20a_instobj(memory);
 232         struct gk20a_instmem *imem = node->imem;
 233         struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
 234 
 235         /* in case we got a write-combined mapping */
 236         wmb();
 237         nvkm_ltc_invalidate(ltc);
 238 }
 239 
 240 static void
 241 gk20a_instobj_release_iommu(struct nvkm_memory *memory)
 242 {
 243         struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
 244         struct gk20a_instmem *imem = node->base.imem;
 245         struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
 246 
 247         mutex_lock(&imem->lock);
 248 
 249         /* we should at least have one user to release... */
 250         if (WARN_ON(node->use_cpt == 0))
 251                 goto out;
 252 
 253         /* add unused objs to the LRU list to recycle their mapping */
 254         if (--node->use_cpt == 0)
 255                 list_add_tail(&node->vaddr_node, &imem->vaddr_lru);
 256 
 257 out:
 258         mutex_unlock(&imem->lock);
 259 
 260         wmb();
 261         nvkm_ltc_invalidate(ltc);
 262 }
 263 
 264 static u32
 265 gk20a_instobj_rd32(struct nvkm_memory *memory, u64 offset)
 266 {
 267         struct gk20a_instobj *node = gk20a_instobj(memory);
 268 
 269         return node->vaddr[offset / 4];
 270 }
 271 
 272 static void
 273 gk20a_instobj_wr32(struct nvkm_memory *memory, u64 offset, u32 data)
 274 {
 275         struct gk20a_instobj *node = gk20a_instobj(memory);
 276 
 277         node->vaddr[offset / 4] = data;
 278 }
 279 
 280 static int
 281 gk20a_instobj_map(struct nvkm_memory *memory, u64 offset, struct nvkm_vmm *vmm,
 282                   struct nvkm_vma *vma, void *argv, u32 argc)
 283 {
 284         struct gk20a_instobj *node = gk20a_instobj(memory);
 285         struct nvkm_vmm_map map = {
 286                 .memory = &node->memory,
 287                 .offset = offset,
 288                 .mem = node->mn,
 289         };
 290 
 291         return nvkm_vmm_map(vmm, vma, argv, argc, &map);
 292 }
 293 
 294 static void *
 295 gk20a_instobj_dtor_dma(struct nvkm_memory *memory)
 296 {
 297         struct gk20a_instobj_dma *node = gk20a_instobj_dma(memory);
 298         struct gk20a_instmem *imem = node->base.imem;
 299         struct device *dev = imem->base.subdev.device->dev;
 300 
 301         if (unlikely(!node->base.vaddr))
 302                 goto out;
 303 
 304         dma_free_attrs(dev, (u64)node->base.mn->length << PAGE_SHIFT,
 305                        node->base.vaddr, node->handle, imem->attrs);
 306 
 307 out:
 308         return node;
 309 }
 310 
 311 static void *
 312 gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
 313 {
 314         struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
 315         struct gk20a_instmem *imem = node->base.imem;
 316         struct device *dev = imem->base.subdev.device->dev;
 317         struct nvkm_mm_node *r = node->base.mn;
 318         int i;
 319 
 320         if (unlikely(!r))
 321                 goto out;
 322 
 323         mutex_lock(&imem->lock);
 324 
 325         /* vaddr has already been recycled */
 326         if (node->base.vaddr)
 327                 gk20a_instobj_iommu_recycle_vaddr(node);
 328 
 329         mutex_unlock(&imem->lock);
 330 
 331         /* clear IOMMU bit to unmap pages */
 332         r->offset &= ~BIT(imem->iommu_bit - imem->iommu_pgshift);
 333 
 334         /* Unmap pages from GPU address space and free them */
 335         for (i = 0; i < node->base.mn->length; i++) {
 336                 iommu_unmap(imem->domain,
 337                             (r->offset + i) << imem->iommu_pgshift, PAGE_SIZE);
 338                 dma_unmap_page(dev, node->dma_addrs[i], PAGE_SIZE,
 339                                DMA_BIDIRECTIONAL);
 340                 __free_page(node->pages[i]);
 341         }
 342 
 343         /* Release area from GPU address space */
 344         mutex_lock(imem->mm_mutex);
 345         nvkm_mm_free(imem->mm, &r);
 346         mutex_unlock(imem->mm_mutex);
 347 
 348 out:
 349         return node;
 350 }
 351 
 352 static const struct nvkm_memory_func
 353 gk20a_instobj_func_dma = {
 354         .dtor = gk20a_instobj_dtor_dma,
 355         .target = gk20a_instobj_target,
 356         .page = gk20a_instobj_page,
 357         .addr = gk20a_instobj_addr,
 358         .size = gk20a_instobj_size,
 359         .acquire = gk20a_instobj_acquire_dma,
 360         .release = gk20a_instobj_release_dma,
 361         .map = gk20a_instobj_map,
 362 };
 363 
 364 static const struct nvkm_memory_func
 365 gk20a_instobj_func_iommu = {
 366         .dtor = gk20a_instobj_dtor_iommu,
 367         .target = gk20a_instobj_target,
 368         .page = gk20a_instobj_page,
 369         .addr = gk20a_instobj_addr,
 370         .size = gk20a_instobj_size,
 371         .acquire = gk20a_instobj_acquire_iommu,
 372         .release = gk20a_instobj_release_iommu,
 373         .map = gk20a_instobj_map,
 374 };
 375 
 376 static const struct nvkm_memory_ptrs
 377 gk20a_instobj_ptrs = {
 378         .rd32 = gk20a_instobj_rd32,
 379         .wr32 = gk20a_instobj_wr32,
 380 };
 381 
 382 static int
 383 gk20a_instobj_ctor_dma(struct gk20a_instmem *imem, u32 npages, u32 align,
 384                        struct gk20a_instobj **_node)
 385 {
 386         struct gk20a_instobj_dma *node;
 387         struct nvkm_subdev *subdev = &imem->base.subdev;
 388         struct device *dev = subdev->device->dev;
 389 
 390         if (!(node = kzalloc(sizeof(*node), GFP_KERNEL)))
 391                 return -ENOMEM;
 392         *_node = &node->base;
 393 
 394         nvkm_memory_ctor(&gk20a_instobj_func_dma, &node->base.memory);
 395         node->base.memory.ptrs = &gk20a_instobj_ptrs;
 396 
 397         node->base.vaddr = dma_alloc_attrs(dev, npages << PAGE_SHIFT,
 398                                            &node->handle, GFP_KERNEL,
 399                                            imem->attrs);
 400         if (!node->base.vaddr) {
 401                 nvkm_error(subdev, "cannot allocate DMA memory\n");
 402                 return -ENOMEM;
 403         }
 404 
 405         /* alignment check */
 406         if (unlikely(node->handle & (align - 1)))
 407                 nvkm_warn(subdev,
 408                           "memory not aligned as requested: %pad (0x%x)\n",
 409                           &node->handle, align);
 410 
 411         /* present memory for being mapped using small pages */
 412         node->r.type = 12;
 413         node->r.offset = node->handle >> 12;
 414         node->r.length = (npages << PAGE_SHIFT) >> 12;
 415 
 416         node->base.mn = &node->r;
 417         return 0;
 418 }
 419 
 420 static int
 421 gk20a_instobj_ctor_iommu(struct gk20a_instmem *imem, u32 npages, u32 align,
 422                          struct gk20a_instobj **_node)
 423 {
 424         struct gk20a_instobj_iommu *node;
 425         struct nvkm_subdev *subdev = &imem->base.subdev;
 426         struct device *dev = subdev->device->dev;
 427         struct nvkm_mm_node *r;
 428         int ret;
 429         int i;
 430 
 431         /*
 432          * despite their variable size, instmem allocations are small enough
 433          * (< 1 page) to be handled by kzalloc
 434          */
 435         if (!(node = kzalloc(sizeof(*node) + ((sizeof(node->pages[0]) +
 436                              sizeof(*node->dma_addrs)) * npages), GFP_KERNEL)))
 437                 return -ENOMEM;
 438         *_node = &node->base;
 439         node->dma_addrs = (void *)(node->pages + npages);
 440 
 441         nvkm_memory_ctor(&gk20a_instobj_func_iommu, &node->base.memory);
 442         node->base.memory.ptrs = &gk20a_instobj_ptrs;
 443 
 444         /* Allocate backing memory */
 445         for (i = 0; i < npages; i++) {
 446                 struct page *p = alloc_page(GFP_KERNEL);
 447                 dma_addr_t dma_adr;
 448 
 449                 if (p == NULL) {
 450                         ret = -ENOMEM;
 451                         goto free_pages;
 452                 }
 453                 node->pages[i] = p;
 454                 dma_adr = dma_map_page(dev, p, 0, PAGE_SIZE, DMA_BIDIRECTIONAL);
 455                 if (dma_mapping_error(dev, dma_adr)) {
 456                         nvkm_error(subdev, "DMA mapping error!\n");
 457                         ret = -ENOMEM;
 458                         goto free_pages;
 459                 }
 460                 node->dma_addrs[i] = dma_adr;
 461         }
 462 
 463         mutex_lock(imem->mm_mutex);
 464         /* Reserve area from GPU address space */
 465         ret = nvkm_mm_head(imem->mm, 0, 1, npages, npages,
 466                            align >> imem->iommu_pgshift, &r);
 467         mutex_unlock(imem->mm_mutex);
 468         if (ret) {
 469                 nvkm_error(subdev, "IOMMU space is full!\n");
 470                 goto free_pages;
 471         }
 472 
 473         /* Map into GPU address space */
 474         for (i = 0; i < npages; i++) {
 475                 u32 offset = (r->offset + i) << imem->iommu_pgshift;
 476 
 477                 ret = iommu_map(imem->domain, offset, node->dma_addrs[i],
 478                                 PAGE_SIZE, IOMMU_READ | IOMMU_WRITE);
 479                 if (ret < 0) {
 480                         nvkm_error(subdev, "IOMMU mapping failure: %d\n", ret);
 481 
 482                         while (i-- > 0) {
 483                                 offset -= PAGE_SIZE;
 484                                 iommu_unmap(imem->domain, offset, PAGE_SIZE);
 485                         }
 486                         goto release_area;
 487                 }
 488         }
 489 
 490         /* IOMMU bit tells that an address is to be resolved through the IOMMU */
 491         r->offset |= BIT(imem->iommu_bit - imem->iommu_pgshift);
 492 
 493         node->base.mn = r;
 494         return 0;
 495 
 496 release_area:
 497         mutex_lock(imem->mm_mutex);
 498         nvkm_mm_free(imem->mm, &r);
 499         mutex_unlock(imem->mm_mutex);
 500 
 501 free_pages:
 502         for (i = 0; i < npages && node->pages[i] != NULL; i++) {
 503                 dma_addr_t dma_addr = node->dma_addrs[i];
 504                 if (dma_addr)
 505                         dma_unmap_page(dev, dma_addr, PAGE_SIZE,
 506                                        DMA_BIDIRECTIONAL);
 507                 __free_page(node->pages[i]);
 508         }
 509 
 510         return ret;
 511 }
 512 
 513 static int
 514 gk20a_instobj_new(struct nvkm_instmem *base, u32 size, u32 align, bool zero,
 515                   struct nvkm_memory **pmemory)
 516 {
 517         struct gk20a_instmem *imem = gk20a_instmem(base);
 518         struct nvkm_subdev *subdev = &imem->base.subdev;
 519         struct gk20a_instobj *node = NULL;
 520         int ret;
 521 
 522         nvkm_debug(subdev, "%s (%s): size: %x align: %x\n", __func__,
 523                    imem->domain ? "IOMMU" : "DMA", size, align);
 524 
 525         /* Round size and align to page bounds */
 526         size = max(roundup(size, PAGE_SIZE), PAGE_SIZE);
 527         align = max(roundup(align, PAGE_SIZE), PAGE_SIZE);
 528 
 529         if (imem->domain)
 530                 ret = gk20a_instobj_ctor_iommu(imem, size >> PAGE_SHIFT,
 531                                                align, &node);
 532         else
 533                 ret = gk20a_instobj_ctor_dma(imem, size >> PAGE_SHIFT,
 534                                              align, &node);
 535         *pmemory = node ? &node->memory : NULL;
 536         if (ret)
 537                 return ret;
 538 
 539         node->imem = imem;
 540 
 541         nvkm_debug(subdev, "alloc size: 0x%x, align: 0x%x, gaddr: 0x%llx\n",
 542                    size, align, (u64)node->mn->offset << 12);
 543 
 544         return 0;
 545 }
 546 
 547 static void *
 548 gk20a_instmem_dtor(struct nvkm_instmem *base)
 549 {
 550         struct gk20a_instmem *imem = gk20a_instmem(base);
 551 
 552         /* perform some sanity checks... */
 553         if (!list_empty(&imem->vaddr_lru))
 554                 nvkm_warn(&base->subdev, "instobj LRU not empty!\n");
 555 
 556         if (imem->vaddr_use != 0)
 557                 nvkm_warn(&base->subdev, "instobj vmap area not empty! "
 558                           "0x%x bytes still mapped\n", imem->vaddr_use);
 559 
 560         return imem;
 561 }
 562 
 563 static const struct nvkm_instmem_func
 564 gk20a_instmem = {
 565         .dtor = gk20a_instmem_dtor,
 566         .memory_new = gk20a_instobj_new,
 567         .zero = false,
 568 };
 569 
 570 int
 571 gk20a_instmem_new(struct nvkm_device *device, int index,
 572                   struct nvkm_instmem **pimem)
 573 {
 574         struct nvkm_device_tegra *tdev = device->func->tegra(device);
 575         struct gk20a_instmem *imem;
 576 
 577         if (!(imem = kzalloc(sizeof(*imem), GFP_KERNEL)))
 578                 return -ENOMEM;
 579         nvkm_instmem_ctor(&gk20a_instmem, device, index, &imem->base);
 580         mutex_init(&imem->lock);
 581         *pimem = &imem->base;
 582 
 583         /* do not allow more than 1MB of CPU-mapped instmem */
 584         imem->vaddr_use = 0;
 585         imem->vaddr_max = 0x100000;
 586         INIT_LIST_HEAD(&imem->vaddr_lru);
 587 
 588         if (tdev->iommu.domain) {
 589                 imem->mm_mutex = &tdev->iommu.mutex;
 590                 imem->mm = &tdev->iommu.mm;
 591                 imem->domain = tdev->iommu.domain;
 592                 imem->iommu_pgshift = tdev->iommu.pgshift;
 593                 imem->iommu_bit = tdev->func->iommu_bit;
 594 
 595                 nvkm_info(&imem->base.subdev, "using IOMMU\n");
 596         } else {
 597                 imem->attrs = DMA_ATTR_NON_CONSISTENT |
 598                               DMA_ATTR_WEAK_ORDERING |
 599                               DMA_ATTR_WRITE_COMBINE;
 600 
 601                 nvkm_info(&imem->base.subdev, "using DMA API\n");
 602         }
 603 
 604         return 0;
 605 }