drivers/base/dma-coherent.c

   1 /*
   2  * Coherent per-device memory handling.
   3  * Borrowed from i386
   4  */
   5 #include <linux/io.h>
   6 #include <linux/slab.h>
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/dma-mapping.h>
  10
  11 struct dma_coherent_mem {
  12         void            *virt_base;
  13         dma_addr_t      device_base;
  14         unsigned long   pfn_base;
  15         int             size;
  16         int             flags;
  17         unsigned long   *bitmap;
  18         spinlock_t      spinlock;
  19         bool            use_dev_dma_pfn_offset;
  20 };
  21
  22 static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
  23
  24 static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
  25 {
  26         if (dev && dev->dma_mem)
  27                 return dev->dma_mem;
  28         return NULL;
  29 }
  30
  31 static inline dma_addr_t dma_get_device_base(struct device *dev,
  32                                              struct dma_coherent_mem * mem)
  33 {
  34         if (mem->use_dev_dma_pfn_offset)
  35                 return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
  36         else
  37                 return mem->device_base;
  38 }
  39
  40 static bool dma_init_coherent_memory(
  41         phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags,
  42         struct dma_coherent_mem **mem)
  43 {
  44         struct dma_coherent_mem *dma_mem = NULL;
  45         void __iomem *mem_base = NULL;
  46         int pages = size >> PAGE_SHIFT;
  47         int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
  48
  49         if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
  50                 goto out;
  51         if (!size)
  52                 goto out;
  53
  54         if (flags & DMA_MEMORY_MAP)
  55                 mem_base = memremap(phys_addr, size, MEMREMAP_WC);
  56         else
  57                 mem_base = ioremap(phys_addr, size);
  58         if (!mem_base)
  59                 goto out;
  60
  61         dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
  62         if (!dma_mem)
  63                 goto out;
  64         dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
  65         if (!dma_mem->bitmap)
  66                 goto out;
  67
  68         dma_mem->virt_base = mem_base;
  69         dma_mem->device_base = device_addr;
  70         dma_mem->pfn_base = PFN_DOWN(phys_addr);
  71         dma_mem->size = pages;
  72         dma_mem->flags = flags;
  73         spin_lock_init(&dma_mem->spinlock);
  74
  75         *mem = dma_mem;
  76         return true;
  77
  78 out:
  79         kfree(dma_mem);
  80         if (mem_base) {
  81                 if (flags & DMA_MEMORY_MAP)
  82                         memunmap(mem_base);
  83                 else
  84                         iounmap(mem_base);
  85         }
  86         return false;
  87 }
  88
  89 static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
  90 {
  91         if (!mem)
  92                 return;
  93
  94         if (mem->flags & DMA_MEMORY_MAP)
  95                 memunmap(mem->virt_base);
  96         else
  97                 iounmap(mem->virt_base);
  98         kfree(mem->bitmap);
  99         kfree(mem);
 100 }
 101
 102 static int dma_assign_coherent_memory(struct device *dev,
 103                                       struct dma_coherent_mem *mem)
 104 {
 105         if (!dev)
 106                 return -ENODEV;
 107
 108         if (dev->dma_mem)
 109                 return -EBUSY;
 110
 111         dev->dma_mem = mem;
 112         /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
 113
 114         return 0;
 115 }
 116
 117 int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
 118                                 dma_addr_t device_addr, size_t size, int flags)
 119 {
 120         struct dma_coherent_mem *mem;
 121
 122         if (!dma_init_coherent_memory(phys_addr, device_addr, size, flags,
 123                                       &mem))
 124                 return 0;
 125
 126         if (dma_assign_coherent_memory(dev, mem) == 0)
 127                 return flags & DMA_MEMORY_MAP ? DMA_MEMORY_MAP : DMA_MEMORY_IO;
 128
 129         dma_release_coherent_memory(mem);
 130         return 0;
 131 }
 132 EXPORT_SYMBOL(dma_declare_coherent_memory);
 133
 134 void dma_release_declared_memory(struct device *dev)
 135 {
 136         struct dma_coherent_mem *mem = dev->dma_mem;
 137
 138         if (!mem)
 139                 return;
 140         dma_release_coherent_memory(mem);
 141         dev->dma_mem = NULL;
 142 }
 143 EXPORT_SYMBOL(dma_release_declared_memory);
 144
 145 void *dma_mark_declared_memory_occupied(struct device *dev,
 146                                         dma_addr_t device_addr, size_t size)
 147 {
 148         struct dma_coherent_mem *mem = dev->dma_mem;
 149         unsigned long flags;
 150         int pos, err;
 151
 152         size += device_addr & ~PAGE_MASK;
 153
 154         if (!mem)
 155                 return ERR_PTR(-EINVAL);
 156
 157         spin_lock_irqsave(&mem->spinlock, flags);
 158         pos = PFN_DOWN(device_addr - dma_get_device_base(dev, mem));
 159         err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
 160         spin_unlock_irqrestore(&mem->spinlock, flags);
 161
 162         if (err != 0)
 163                 return ERR_PTR(err);
 164         return mem->virt_base + (pos << PAGE_SHIFT);
 165 }
 166 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
 167
 168 static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
 169                 ssize_t size, dma_addr_t *dma_handle)
 170 {
 171         int order = get_order(size);
 172         unsigned long flags;
 173         int pageno;
 174         int dma_memory_map;
 175         void *ret;
 176
 177         spin_lock_irqsave(&mem->spinlock, flags);
 178
 179         if (unlikely(size > (mem->size << PAGE_SHIFT)))
 180                 goto err;
 181
 182         pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
 183         if (unlikely(pageno < 0))
 184                 goto err;
 185
 186         /*
 187          * Memory was found in the coherent area.
 188          */
 189         *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
 190         ret = mem->virt_base + (pageno << PAGE_SHIFT);
 191         dma_memory_map = (mem->flags & DMA_MEMORY_MAP);
 192         spin_unlock_irqrestore(&mem->spinlock, flags);
 193         if (dma_memory_map)
 194                 memset(ret, 0, size);
 195         else
 196                 memset_io(ret, 0, size);
 197
 198         return ret;
 199
 200 err:
 201         spin_unlock_irqrestore(&mem->spinlock, flags);
 202         return NULL;
 203 }
 204
 205 /**
 206  * dma_alloc_from_dev_coherent() - allocate memory from device coherent pool
 207  * @dev:        device from which we allocate memory
 208  * @size:       size of requested memory area
 209  * @dma_handle: This will be filled with the correct dma handle
 210  * @ret:        This pointer will be filled with the virtual address
 211  *              to allocated area.
 212  *
 213  * This function should be only called from per-arch dma_alloc_coherent()
 214  * to support allocation from per-device coherent memory pools.
 215  *
 216  * Returns 0 if dma_alloc_coherent should continue with allocating from
 217  * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
 218  */
 219 int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
 220                 dma_addr_t *dma_handle, void **ret)
 221 {
 222         struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
 223
 224         if (!mem)
 225                 return 0;
 226
 227         *ret = __dma_alloc_from_coherent(mem, size, dma_handle);
 228         if (*ret)
 229                 return 1;
 230
 231         /*
 232          * In the case where the allocation can not be satisfied from the
 233          * per-device area, try to fall back to generic memory if the
 234          * constraints allow it.
 235          */
 236         return mem->flags & DMA_MEMORY_EXCLUSIVE;
 237 }
 238 EXPORT_SYMBOL(dma_alloc_from_dev_coherent);
 239
 240 void *dma_alloc_from_global_coherent(ssize_t size, dma_addr_t *dma_handle)
 241 {
 242         if (!dma_coherent_default_memory)
 243                 return NULL;
 244
 245         return __dma_alloc_from_coherent(dma_coherent_default_memory, size,
 246                         dma_handle);
 247 }
 248
 249 static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
 250                                        int order, void *vaddr)
 251 {
 252         if (mem && vaddr >= mem->virt_base && vaddr <
 253                    (mem->virt_base + (mem->size << PAGE_SHIFT))) {
 254                 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
 255                 unsigned long flags;
 256
 257                 spin_lock_irqsave(&mem->spinlock, flags);
 258                 bitmap_release_region(mem->bitmap, page, order);
 259                 spin_unlock_irqrestore(&mem->spinlock, flags);
 260                 return 1;
 261         }
 262         return 0;
 263 }
 264
 265 /**
 266  * dma_release_from_dev_coherent() - free memory to device coherent memory pool
 267  * @dev:        device from which the memory was allocated
 268  * @order:      the order of pages allocated
 269  * @vaddr:      virtual address of allocated pages
 270  *
 271  * This checks whether the memory was allocated from the per-device
 272  * coherent memory pool and if so, releases that memory.
 273  *
 274  * Returns 1 if we correctly released the memory, or 0 if the caller should
 275  * proceed with releasing memory from generic pools.
 276  */
 277 int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
 278 {
 279         struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
 280
 281         return __dma_release_from_coherent(mem, order, vaddr);
 282 }
 283 EXPORT_SYMBOL(dma_release_from_dev_coherent);
 284
 285 int dma_release_from_global_coherent(int order, void *vaddr)
 286 {
 287         if (!dma_coherent_default_memory)
 288                 return 0;
 289
 290         return __dma_release_from_coherent(dma_coherent_default_memory, order,
 291                         vaddr);
 292 }
 293
 294 static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
 295                 struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
 296 {
 297         if (mem && vaddr >= mem->virt_base && vaddr + size <=
 298                    (mem->virt_base + (mem->size << PAGE_SHIFT))) {
 299                 unsigned long off = vma->vm_pgoff;
 300                 int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
 301                 int user_count = vma_pages(vma);
 302                 int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 303
 304                 *ret = -ENXIO;
 305                 if (off < count && user_count <= count - off) {
 306                         unsigned long pfn = mem->pfn_base + start + off;
 307                         *ret = remap_pfn_range(vma, vma->vm_start, pfn,
 308                                                user_count << PAGE_SHIFT,
 309                                                vma->vm_page_prot);
 310                 }
 311                 return 1;
 312         }
 313         return 0;
 314 }
 315
 316 /**
 317  * dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
 318  * @dev:        device from which the memory was allocated
 319  * @vma:        vm_area for the userspace memory
 320  * @vaddr:      cpu address returned by dma_alloc_from_dev_coherent
 321  * @size:       size of the memory buffer allocated
 322  * @ret:        result from remap_pfn_range()
 323  *
 324  * This checks whether the memory was allocated from the per-device
 325  * coherent memory pool and if so, maps that memory to the provided vma.
 326  *
 327  * Returns 1 if we correctly mapped the memory, or 0 if the caller should
 328  * proceed with mapping memory from generic pools.
 329  */
 330 int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
 331                            void *vaddr, size_t size, int *ret)
 332 {
 333         struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
 334
 335         return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
 336 }
 337 EXPORT_SYMBOL(dma_mmap_from_dev_coherent);
 338
 339 int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
 340                                    size_t size, int *ret)
 341 {
 342         if (!dma_coherent_default_memory)
 343                 return 0;
 344
 345         return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
 346                                         vaddr, size, ret);
 347 }
 348
 349 /*
 350  * Support for reserved memory regions defined in device tree
 351  */
 352 #ifdef CONFIG_OF_RESERVED_MEM
 353 #include <linux/of.h>
 354 #include <linux/of_fdt.h>
 355 #include <linux/of_reserved_mem.h>
 356
 357 static struct reserved_mem *dma_reserved_default_memory __initdata;
 358
 359 static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
 360 {
 361         struct dma_coherent_mem *mem = rmem->priv;
 362
 363         if (!mem &&
 364             !dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
 365                                       DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
 366                                       &mem)) {
 367                 pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
 368                         &rmem->base, (unsigned long)rmem->size / SZ_1M);
 369                 return -ENODEV;
 370         }
 371         mem->use_dev_dma_pfn_offset = true;
 372         rmem->priv = mem;
 373         dma_assign_coherent_memory(dev, mem);
 374         return 0;
 375 }
 376
 377 static void rmem_dma_device_release(struct reserved_mem *rmem,
 378                                     struct device *dev)
 379 {
 380         if (dev)
 381                 dev->dma_mem = NULL;
 382 }
 383
 384 static const struct reserved_mem_ops rmem_dma_ops = {
 385         .device_init    = rmem_dma_device_init,
 386         .device_release = rmem_dma_device_release,
 387 };
 388
 389 static int __init rmem_dma_setup(struct reserved_mem *rmem)
 390 {
 391         unsigned long node = rmem->fdt_node;
 392
 393         if (of_get_flat_dt_prop(node, "reusable", NULL))
 394                 return -EINVAL;
 395
 396 #ifdef CONFIG_ARM
 397         if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
 398                 pr_err("Reserved memory: regions without no-map are not yet supported\n");
 399                 return -EINVAL;
 400         }
 401
 402         if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
 403                 WARN(dma_reserved_default_memory,
 404                      "Reserved memory: region for default DMA coherent area is redefined\n");
 405                 dma_reserved_default_memory = rmem;
 406         }
 407 #endif
 408
 409         rmem->ops = &rmem_dma_ops;
 410         pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
 411                 &rmem->base, (unsigned long)rmem->size / SZ_1M);
 412         return 0;
 413 }
 414
 415 static int __init dma_init_reserved_memory(void)
 416 {
 417         const struct reserved_mem_ops *ops;
 418         int ret;
 419
 420         if (!dma_reserved_default_memory)
 421                 return -ENOMEM;
 422
 423         ops = dma_reserved_default_memory->ops;
 424
 425         /*
 426          * We rely on rmem_dma_device_init() does not propagate error of
 427          * dma_assign_coherent_memory() for "NULL" device.
 428          */
 429         ret = ops->device_init(dma_reserved_default_memory, NULL);
 430
 431         if (!ret) {
 432                 dma_coherent_default_memory = dma_reserved_default_memory->priv;
 433                 pr_info("DMA: default coherent area is set\n");
 434         }
 435
 436         return ret;
 437 }
 438
 439 core_initcall(dma_init_reserved_memory);
 440
 441 RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
 442 #endif