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