1/* 2 * Coherent per-device memory handling. 3 * Borrowed from i386 4 */ 5#include <linux/slab.h> 6#include <linux/kernel.h> 7#include <linux/module.h> 8#include <linux/dma-mapping.h> 9 10struct dma_coherent_mem { 11 void *virt_base; 12 dma_addr_t device_base; 13 unsigned long pfn_base; 14 int size; 15 int flags; 16 unsigned long *bitmap; 17 spinlock_t spinlock; 18}; 19 20static int dma_init_coherent_memory(phys_addr_t phys_addr, dma_addr_t device_addr, 21 size_t size, int flags, 22 struct dma_coherent_mem **mem) 23{ 24 struct dma_coherent_mem *dma_mem = NULL; 25 void __iomem *mem_base = NULL; 26 int pages = size >> PAGE_SHIFT; 27 int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long); 28 29 if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0) 30 goto out; 31 if (!size) 32 goto out; 33 34 mem_base = ioremap(phys_addr, size); 35 if (!mem_base) 36 goto out; 37 38 dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL); 39 if (!dma_mem) 40 goto out; 41 dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL); 42 if (!dma_mem->bitmap) 43 goto out; 44 45 dma_mem->virt_base = mem_base; 46 dma_mem->device_base = device_addr; 47 dma_mem->pfn_base = PFN_DOWN(phys_addr); 48 dma_mem->size = pages; 49 dma_mem->flags = flags; 50 spin_lock_init(&dma_mem->spinlock); 51 52 *mem = dma_mem; 53 54 if (flags & DMA_MEMORY_MAP) 55 return DMA_MEMORY_MAP; 56 57 return DMA_MEMORY_IO; 58 59out: 60 kfree(dma_mem); 61 if (mem_base) 62 iounmap(mem_base); 63 return 0; 64} 65 66static void dma_release_coherent_memory(struct dma_coherent_mem *mem) 67{ 68 if (!mem) 69 return; 70 iounmap(mem->virt_base); 71 kfree(mem->bitmap); 72 kfree(mem); 73} 74 75static int dma_assign_coherent_memory(struct device *dev, 76 struct dma_coherent_mem *mem) 77{ 78 if (dev->dma_mem) 79 return -EBUSY; 80 81 dev->dma_mem = mem; 82 /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */ 83 84 return 0; 85} 86 87int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr, 88 dma_addr_t device_addr, size_t size, int flags) 89{ 90 struct dma_coherent_mem *mem; 91 int ret; 92 93 ret = dma_init_coherent_memory(phys_addr, device_addr, size, flags, 94 &mem); 95 if (ret == 0) 96 return 0; 97 98 if (dma_assign_coherent_memory(dev, mem) == 0) 99 return ret; 100 101 dma_release_coherent_memory(mem); 102 return 0; 103} 104EXPORT_SYMBOL(dma_declare_coherent_memory); 105 106void dma_release_declared_memory(struct device *dev) 107{ 108 struct dma_coherent_mem *mem = dev->dma_mem; 109 110 if (!mem) 111 return; 112 dma_release_coherent_memory(mem); 113 dev->dma_mem = NULL; 114} 115EXPORT_SYMBOL(dma_release_declared_memory); 116 117void *dma_mark_declared_memory_occupied(struct device *dev, 118 dma_addr_t device_addr, size_t size) 119{ 120 struct dma_coherent_mem *mem = dev->dma_mem; 121 unsigned long flags; 122 int pos, err; 123 124 size += device_addr & ~PAGE_MASK; 125 126 if (!mem) 127 return ERR_PTR(-EINVAL); 128 129 spin_lock_irqsave(&mem->spinlock, flags); 130 pos = (device_addr - mem->device_base) >> PAGE_SHIFT; 131 err = bitmap_allocate_region(mem->bitmap, pos, get_order(size)); 132 spin_unlock_irqrestore(&mem->spinlock, flags); 133 134 if (err != 0) 135 return ERR_PTR(err); 136 return mem->virt_base + (pos << PAGE_SHIFT); 137} 138EXPORT_SYMBOL(dma_mark_declared_memory_occupied); 139 140/** 141 * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area 142 * 143 * @dev: device from which we allocate memory 144 * @size: size of requested memory area 145 * @dma_handle: This will be filled with the correct dma handle 146 * @ret: This pointer will be filled with the virtual address 147 * to allocated area. 148 * 149 * This function should be only called from per-arch dma_alloc_coherent() 150 * to support allocation from per-device coherent memory pools. 151 * 152 * Returns 0 if dma_alloc_coherent should continue with allocating from 153 * generic memory areas, or !0 if dma_alloc_coherent should return @ret. 154 */ 155int dma_alloc_from_coherent(struct device *dev, ssize_t size, 156 dma_addr_t *dma_handle, void **ret) 157{ 158 struct dma_coherent_mem *mem; 159 int order = get_order(size); 160 unsigned long flags; 161 int pageno; 162 163 if (!dev) 164 return 0; 165 mem = dev->dma_mem; 166 if (!mem) 167 return 0; 168 169 *ret = NULL; 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 per-device area. 181 */ 182 *dma_handle = mem->device_base + (pageno << PAGE_SHIFT); 183 *ret = mem->virt_base + (pageno << PAGE_SHIFT); 184 memset(*ret, 0, size); 185 spin_unlock_irqrestore(&mem->spinlock, flags); 186 187 return 1; 188 189err: 190 spin_unlock_irqrestore(&mem->spinlock, flags); 191 /* 192 * In the case where the allocation can not be satisfied from the 193 * per-device area, try to fall back to generic memory if the 194 * constraints allow it. 195 */ 196 return mem->flags & DMA_MEMORY_EXCLUSIVE; 197} 198EXPORT_SYMBOL(dma_alloc_from_coherent); 199 200/** 201 * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool 202 * @dev: device from which the memory was allocated 203 * @order: the order of pages allocated 204 * @vaddr: virtual address of allocated pages 205 * 206 * This checks whether the memory was allocated from the per-device 207 * coherent memory pool and if so, releases that memory. 208 * 209 * Returns 1 if we correctly released the memory, or 0 if 210 * dma_release_coherent() should proceed with releasing memory from 211 * generic pools. 212 */ 213int dma_release_from_coherent(struct device *dev, int order, void *vaddr) 214{ 215 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; 216 217 if (mem && vaddr >= mem->virt_base && vaddr < 218 (mem->virt_base + (mem->size << PAGE_SHIFT))) { 219 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT; 220 unsigned long flags; 221 222 spin_lock_irqsave(&mem->spinlock, flags); 223 bitmap_release_region(mem->bitmap, page, order); 224 spin_unlock_irqrestore(&mem->spinlock, flags); 225 return 1; 226 } 227 return 0; 228} 229EXPORT_SYMBOL(dma_release_from_coherent); 230 231/** 232 * dma_mmap_from_coherent() - try to mmap the memory allocated from 233 * per-device coherent memory pool to userspace 234 * @dev: device from which the memory was allocated 235 * @vma: vm_area for the userspace memory 236 * @vaddr: cpu address returned by dma_alloc_from_coherent 237 * @size: size of the memory buffer allocated by dma_alloc_from_coherent 238 * @ret: result from remap_pfn_range() 239 * 240 * This checks whether the memory was allocated from the per-device 241 * coherent memory pool and if so, maps that memory to the provided vma. 242 * 243 * Returns 1 if we correctly mapped the memory, or 0 if the caller should 244 * proceed with mapping memory from generic pools. 245 */ 246int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma, 247 void *vaddr, size_t size, int *ret) 248{ 249 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; 250 251 if (mem && vaddr >= mem->virt_base && vaddr + size <= 252 (mem->virt_base + (mem->size << PAGE_SHIFT))) { 253 unsigned long off = vma->vm_pgoff; 254 int start = (vaddr - mem->virt_base) >> PAGE_SHIFT; 255 int user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 256 int count = size >> PAGE_SHIFT; 257 258 *ret = -ENXIO; 259 if (off < count && user_count <= count - off) { 260 unsigned long pfn = mem->pfn_base + start + off; 261 *ret = remap_pfn_range(vma, vma->vm_start, pfn, 262 user_count << PAGE_SHIFT, 263 vma->vm_page_prot); 264 } 265 return 1; 266 } 267 return 0; 268} 269EXPORT_SYMBOL(dma_mmap_from_coherent); 270 271/* 272 * Support for reserved memory regions defined in device tree 273 */ 274#ifdef CONFIG_OF_RESERVED_MEM 275#include <linux/of.h> 276#include <linux/of_fdt.h> 277#include <linux/of_reserved_mem.h> 278 279static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev) 280{ 281 struct dma_coherent_mem *mem = rmem->priv; 282 283 if (!mem && 284 dma_init_coherent_memory(rmem->base, rmem->base, rmem->size, 285 DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE, 286 &mem) != DMA_MEMORY_MAP) { 287 pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n", 288 &rmem->base, (unsigned long)rmem->size / SZ_1M); 289 return -ENODEV; 290 } 291 rmem->priv = mem; 292 dma_assign_coherent_memory(dev, mem); 293 return 0; 294} 295 296static void rmem_dma_device_release(struct reserved_mem *rmem, 297 struct device *dev) 298{ 299 dev->dma_mem = NULL; 300} 301 302static const struct reserved_mem_ops rmem_dma_ops = { 303 .device_init = rmem_dma_device_init, 304 .device_release = rmem_dma_device_release, 305}; 306 307static int __init rmem_dma_setup(struct reserved_mem *rmem) 308{ 309 unsigned long node = rmem->fdt_node; 310 311 if (of_get_flat_dt_prop(node, "reusable", NULL)) 312 return -EINVAL; 313 314#ifdef CONFIG_ARM 315 if (!of_get_flat_dt_prop(node, "no-map", NULL)) { 316 pr_err("Reserved memory: regions without no-map are not yet supported\n"); 317 return -EINVAL; 318 } 319#endif 320 321 rmem->ops = &rmem_dma_ops; 322 pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n", 323 &rmem->base, (unsigned long)rmem->size / SZ_1M); 324 return 0; 325} 326RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup); 327#endif 328