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