drivers/base/dma-coherent.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Coherent per-device memory handling.
   4  * Borrowed from i386
   5  */
   6 #include <linux/io.h>
   7 #include <linux/slab.h>
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/dma-mapping.h>
  11
  12 struct dma_coherent_mem {
  13         void            *virt_base;
  14         dma_addr_t      device_base;
  15         unsigned long   pfn_base;
  16         int             size;
  17         int             flags;
  18         unsigned long   *bitmap;
  19         spinlock_t      spinlock;
  20         bool            use_dev_dma_pfn_offset;
  21 };
  22
  23 static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
  24
  25 static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
  26 {
  27         if (dev && dev->dma_mem)
  28                 return dev->dma_mem;
  29         return NULL;
  30 }
  31
  32 static inline dma_addr_t dma_get_device_base(struct device *dev,
  33                                              struct dma_coherent_mem * mem)
  34 {
  35         if (mem->use_dev_dma_pfn_offset)
  36                 return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
  37         else
  38                 return mem->device_base;
  39 }
  40
  41 static int dma_init_coherent_memory(
  42         phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags,
  43         struct dma_coherent_mem **mem)
  44 {
  45         struct dma_coherent_mem *dma_mem = NULL;
  46         void __iomem *mem_base = NULL;
  47         int pages = size >> PAGE_SHIFT;
  48         int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
  49         int ret;
  50
  51         if (!size) {
  52                 ret = -EINVAL;
  53                 goto out;
  54         }
  55
  56         mem_base = memremap(phys_addr, size, MEMREMAP_WC);
  57         if (!mem_base) {
  58                 ret = -EINVAL;
  59                 goto out;
  60         }
  61         dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
  62         if (!dma_mem) {
  63                 ret = -ENOMEM;
  64                 goto out;
  65         }
  66         dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
  67         if (!dma_mem->bitmap) {
  68                 ret = -ENOMEM;
  69                 goto out;
  70         }
  71
  72         dma_mem->virt_base = mem_base;
  73         dma_mem->device_base = device_addr;
  74         dma_mem->pfn_base = PFN_DOWN(phys_addr);
  75         dma_mem->size = pages;
  76         dma_mem->flags = flags;
  77         spin_lock_init(&dma_mem->spinlock);
  78
  79         *mem = dma_mem;
  80         return 0;
  81
  82 out:
  83         kfree(dma_mem);
  84         if (mem_base)
  85                 memunmap(mem_base);
  86         return ret;
  87 }
  88
  89 static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
  90 {
  91         if (!mem)
  92                 return;
  93
  94         memunmap(mem->virt_base);
  95         kfree(mem->bitmap);
  96         kfree(mem);
  97 }
  98
  99 static int dma_assign_coherent_memory(struct device *dev,
 100                                       struct dma_coherent_mem *mem)
 101 {
 102         if (!dev)
 103                 return -ENODEV;
 104
 105         if (dev->dma_mem)
 106                 return -EBUSY;
 107
 108         dev->dma_mem = mem;
 109         return 0;
 110 }
 111
 112 int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
 113                                 dma_addr_t device_addr, size_t size, int flags)
 114 {
 115         struct dma_coherent_mem *mem;
 116         int ret;
 117
 118         ret = dma_init_coherent_memory(phys_addr, device_addr, size, flags, &mem);
 119         if (ret)
 120                 return ret;
 121
 122         ret = dma_assign_coherent_memory(dev, mem);
 123         if (ret)
 124                 dma_release_coherent_memory(mem);
 125         return ret;
 126 }
 127 EXPORT_SYMBOL(dma_declare_coherent_memory);
 128
 129 void dma_release_declared_memory(struct device *dev)
 130 {
 131         struct dma_coherent_mem *mem = dev->dma_mem;
 132
 133         if (!mem)
 134                 return;
 135         dma_release_coherent_memory(mem);
 136         dev->dma_mem = NULL;
 137 }
 138 EXPORT_SYMBOL(dma_release_declared_memory);
 139
 140 void *dma_mark_declared_memory_occupied(struct device *dev,
 141                                         dma_addr_t device_addr, size_t size)
 142 {
 143         struct dma_coherent_mem *mem = dev->dma_mem;
 144         unsigned long flags;
 145         int pos, err;
 146
 147         size += device_addr & ~PAGE_MASK;
 148
 149         if (!mem)
 150                 return ERR_PTR(-EINVAL);
 151
 152         spin_lock_irqsave(&mem->spinlock, flags);
 153         pos = PFN_DOWN(device_addr - dma_get_device_base(dev, mem));
 154         err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
 155         spin_unlock_irqrestore(&mem->spinlock, flags);
 156
 157         if (err != 0)
 158                 return ERR_PTR(err);
 159         return mem->virt_base + (pos << PAGE_SHIFT);
 160 }
 161 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
 162
 163 static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
 164                 ssize_t size, dma_addr_t *dma_handle)
 165 {
 166         int order = get_order(size);
 167         unsigned long flags;
 168         int pageno;
 169         void *ret;
 170
 171         spin_lock_irqsave(&mem->spinlock, flags);
 172
 173         if (unlikely(size > (mem->size << PAGE_SHIFT)))
 174                 goto err;
 175
 176         pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
 177         if (unlikely(pageno < 0))
 178                 goto err;
 179
 180         /*
 181          * Memory was found in the coherent area.
 182          */
 183         *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
 184         ret = mem->virt_base + (pageno << PAGE_SHIFT);
 185         spin_unlock_irqrestore(&mem->spinlock, flags);
 186         memset(ret, 0, size);
 187         return ret;
 188 err:
 189         spin_unlock_irqrestore(&mem->spinlock, flags);
 190         return NULL;
 191 }
 192
 193 /**
 194  * dma_alloc_from_dev_coherent() - allocate memory from device coherent pool
 195  * @dev:        device from which we allocate memory
 196  * @size:       size of requested memory area
 197  * @dma_handle: This will be filled with the correct dma handle
 198  * @ret:        This pointer will be filled with the virtual address
 199  *              to allocated area.
 200  *
 201  * This function should be only called from per-arch dma_alloc_coherent()
 202  * to support allocation from per-device coherent memory pools.
 203  *
 204  * Returns 0 if dma_alloc_coherent should continue with allocating from
 205  * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
 206  */
 207 int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
 208                 dma_addr_t *dma_handle, void **ret)
 209 {
 210         struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
 211
 212         if (!mem)
 213                 return 0;
 214
 215         *ret = __dma_alloc_from_coherent(mem, size, dma_handle);
 216         if (*ret)
 217                 return 1;
 218
 219         /*
 220          * In the case where the allocation can not be satisfied from the
 221          * per-device area, try to fall back to generic memory if the
 222          * constraints allow it.
 223          */
 224         return mem->flags & DMA_MEMORY_EXCLUSIVE;
 225 }
 226 EXPORT_SYMBOL(dma_alloc_from_dev_coherent);
 227
 228 void *dma_alloc_from_global_coherent(ssize_t size, dma_addr_t *dma_handle)
 229 {
 230         if (!dma_coherent_default_memory)
 231                 return NULL;
 232
 233         return __dma_alloc_from_coherent(dma_coherent_default_memory, size,
 234                         dma_handle);
 235 }
 236
 237 static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
 238                                        int order, void *vaddr)
 239 {
 240         if (mem && vaddr >= mem->virt_base && vaddr <
 241                    (mem->virt_base + (mem->size << PAGE_SHIFT))) {
 242                 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
 243                 unsigned long flags;
 244
 245                 spin_lock_irqsave(&mem->spinlock, flags);
 246                 bitmap_release_region(mem->bitmap, page, order);
 247                 spin_unlock_irqrestore(&mem->spinlock, flags);
 248                 return 1;
 249         }
 250         return 0;
 251 }
 252
 253 /**
 254  * dma_release_from_dev_coherent() - free memory to device coherent memory pool
 255  * @dev:        device from which the memory was allocated
 256  * @order:      the order of pages allocated
 257  * @vaddr:      virtual address of allocated pages
 258  *
 259  * This checks whether the memory was allocated from the per-device
 260  * coherent memory pool and if so, releases that memory.
 261  *
 262  * Returns 1 if we correctly released the memory, or 0 if the caller should
 263  * proceed with releasing memory from generic pools.
 264  */
 265 int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
 266 {
 267         struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
 268
 269         return __dma_release_from_coherent(mem, order, vaddr);
 270 }
 271 EXPORT_SYMBOL(dma_release_from_dev_coherent);
 272
 273 int dma_release_from_global_coherent(int order, void *vaddr)
 274 {
 275         if (!dma_coherent_default_memory)
 276                 return 0;
 277
 278         return __dma_release_from_coherent(dma_coherent_default_memory, order,
 279                         vaddr);
 280 }
 281
 282 static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
 283                 struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
 284 {
 285         if (mem && vaddr >= mem->virt_base && vaddr + size <=
 286                    (mem->virt_base + (mem->size << PAGE_SHIFT))) {
 287                 unsigned long off = vma->vm_pgoff;
 288                 int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
 289                 int user_count = vma_pages(vma);
 290                 int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 291
 292                 *ret = -ENXIO;
 293                 if (off < count && user_count <= count - off) {
 294                         unsigned long pfn = mem->pfn_base + start + off;
 295                         *ret = remap_pfn_range(vma, vma->vm_start, pfn,
 296                                                user_count << PAGE_SHIFT,
 297                                                vma->vm_page_prot);
 298                 }
 299                 return 1;
 300         }
 301         return 0;
 302 }
 303
 304 /**
 305  * dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
 306  * @dev:        device from which the memory was allocated
 307  * @vma:        vm_area for the userspace memory
 308  * @vaddr:      cpu address returned by dma_alloc_from_dev_coherent
 309  * @size:       size of the memory buffer allocated
 310  * @ret:        result from remap_pfn_range()
 311  *
 312  * This checks whether the memory was allocated from the per-device
 313  * coherent memory pool and if so, maps that memory to the provided vma.
 314  *
 315  * Returns 1 if @vaddr belongs to the device coherent pool and the caller
 316  * should return @ret, or 0 if they should proceed with mapping memory from
 317  * generic areas.
 318  */
 319 int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
 320                            void *vaddr, size_t size, int *ret)
 321 {
 322         struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
 323
 324         return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
 325 }
 326 EXPORT_SYMBOL(dma_mmap_from_dev_coherent);
 327
 328 int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
 329                                    size_t size, int *ret)
 330 {
 331         if (!dma_coherent_default_memory)
 332                 return 0;
 333
 334         return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
 335                                         vaddr, size, ret);
 336 }
 337
 338 /*
 339  * Support for reserved memory regions defined in device tree
 340  */
 341 #ifdef CONFIG_OF_RESERVED_MEM
 342 #include <linux/of.h>
 343 #include <linux/of_fdt.h>
 344 #include <linux/of_reserved_mem.h>
 345
 346 static struct reserved_mem *dma_reserved_default_memory __initdata;
 347
 348 static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
 349 {
 350         struct dma_coherent_mem *mem = rmem->priv;
 351         int ret;
 352
 353         if (!mem) {
 354                 ret = dma_init_coherent_memory(rmem->base, rmem->base,
 355                                                rmem->size,
 356                                                DMA_MEMORY_EXCLUSIVE, &mem);
 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         }
 363         mem->use_dev_dma_pfn_offset = true;
 364         rmem->priv = mem;
 365         dma_assign_coherent_memory(dev, mem);
 366         return 0;
 367 }
 368
 369 static void rmem_dma_device_release(struct reserved_mem *rmem,
 370                                     struct device *dev)
 371 {
 372         if (dev)
 373                 dev->dma_mem = NULL;
 374 }
 375
 376 static const struct reserved_mem_ops rmem_dma_ops = {
 377         .device_init    = rmem_dma_device_init,
 378         .device_release = rmem_dma_device_release,
 379 };
 380
 381 static int __init rmem_dma_setup(struct reserved_mem *rmem)
 382 {
 383         unsigned long node = rmem->fdt_node;
 384
 385         if (of_get_flat_dt_prop(node, "reusable", NULL))
 386                 return -EINVAL;
 387
 388 #ifdef CONFIG_ARM
 389         if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
 390                 pr_err("Reserved memory: regions without no-map are not yet supported\n");
 391                 return -EINVAL;
 392         }
 393
 394         if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
 395                 WARN(dma_reserved_default_memory,
 396                      "Reserved memory: region for default DMA coherent area is redefined\n");
 397                 dma_reserved_default_memory = rmem;
 398         }
 399 #endif
 400
 401         rmem->ops = &rmem_dma_ops;
 402         pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
 403                 &rmem->base, (unsigned long)rmem->size / SZ_1M);
 404         return 0;
 405 }
 406
 407 static int __init dma_init_reserved_memory(void)
 408 {
 409         const struct reserved_mem_ops *ops;
 410         int ret;
 411
 412         if (!dma_reserved_default_memory)
 413                 return -ENOMEM;
 414
 415         ops = dma_reserved_default_memory->ops;
 416
 417         /*
 418          * We rely on rmem_dma_device_init() does not propagate error of
 419          * dma_assign_coherent_memory() for "NULL" device.
 420          */
 421         ret = ops->device_init(dma_reserved_default_memory, NULL);
 422
 423         if (!ret) {
 424                 dma_coherent_default_memory = dma_reserved_default_memory->priv;
 425                 pr_info("DMA: default coherent area is set\n");
 426         }
 427
 428         return ret;
 429 }
 430
 431 core_initcall(dma_init_reserved_memory);
 432
 433 RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
 434 #endif