2 * Coherent per-device memory handling.
6 #include <linux/slab.h>
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/dma-mapping.h>
11 struct dma_coherent_mem {
13 dma_addr_t device_base;
14 unsigned long pfn_base;
17 unsigned long *bitmap;
21 static bool dma_init_coherent_memory(
22 phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags,
23 struct dma_coherent_mem **mem)
25 struct dma_coherent_mem *dma_mem = NULL;
26 void __iomem *mem_base = NULL;
27 int pages = size >> PAGE_SHIFT;
28 int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
30 if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
35 if (flags & DMA_MEMORY_MAP)
36 mem_base = memremap(phys_addr, size, MEMREMAP_WC);
38 mem_base = ioremap(phys_addr, size);
42 dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
45 dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
49 dma_mem->virt_base = mem_base;
50 dma_mem->device_base = device_addr;
51 dma_mem->pfn_base = PFN_DOWN(phys_addr);
52 dma_mem->size = pages;
53 dma_mem->flags = flags;
54 spin_lock_init(&dma_mem->spinlock);
62 if (flags & DMA_MEMORY_MAP)
70 static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
75 if (mem->flags & DMA_MEMORY_MAP)
76 memunmap(mem->virt_base);
78 iounmap(mem->virt_base);
83 static int dma_assign_coherent_memory(struct device *dev,
84 struct dma_coherent_mem *mem)
90 /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
95 int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
96 dma_addr_t device_addr, size_t size, int flags)
98 struct dma_coherent_mem *mem;
100 if (!dma_init_coherent_memory(phys_addr, device_addr, size, flags,
104 if (dma_assign_coherent_memory(dev, mem) == 0)
105 return flags & DMA_MEMORY_MAP ? DMA_MEMORY_MAP : DMA_MEMORY_IO;
107 dma_release_coherent_memory(mem);
110 EXPORT_SYMBOL(dma_declare_coherent_memory);
112 void dma_release_declared_memory(struct device *dev)
114 struct dma_coherent_mem *mem = dev->dma_mem;
118 dma_release_coherent_memory(mem);
121 EXPORT_SYMBOL(dma_release_declared_memory);
123 void *dma_mark_declared_memory_occupied(struct device *dev,
124 dma_addr_t device_addr, size_t size)
126 struct dma_coherent_mem *mem = dev->dma_mem;
130 size += device_addr & ~PAGE_MASK;
133 return ERR_PTR(-EINVAL);
135 spin_lock_irqsave(&mem->spinlock, flags);
136 pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
137 err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
138 spin_unlock_irqrestore(&mem->spinlock, flags);
142 return mem->virt_base + (pos << PAGE_SHIFT);
144 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
147 * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area
149 * @dev: device from which we allocate memory
150 * @size: size of requested memory area
151 * @dma_handle: This will be filled with the correct dma handle
152 * @ret: This pointer will be filled with the virtual address
155 * This function should be only called from per-arch dma_alloc_coherent()
156 * to support allocation from per-device coherent memory pools.
158 * Returns 0 if dma_alloc_coherent should continue with allocating from
159 * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
161 int dma_alloc_from_coherent(struct device *dev, ssize_t size,
162 dma_addr_t *dma_handle, void **ret)
164 struct dma_coherent_mem *mem;
165 int order = get_order(size);
177 spin_lock_irqsave(&mem->spinlock, flags);
179 if (unlikely(size > (mem->size << PAGE_SHIFT)))
182 pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
183 if (unlikely(pageno < 0))
187 * Memory was found in the per-device area.
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);
194 memset(*ret, 0, size);
196 memset_io(*ret, 0, size);
201 spin_unlock_irqrestore(&mem->spinlock, flags);
203 * In the case where the allocation can not be satisfied from the
204 * per-device area, try to fall back to generic memory if the
205 * constraints allow it.
207 return mem->flags & DMA_MEMORY_EXCLUSIVE;
209 EXPORT_SYMBOL(dma_alloc_from_coherent);
212 * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
213 * @dev: device from which the memory was allocated
214 * @order: the order of pages allocated
215 * @vaddr: virtual address of allocated pages
217 * This checks whether the memory was allocated from the per-device
218 * coherent memory pool and if so, releases that memory.
220 * Returns 1 if we correctly released the memory, or 0 if
221 * dma_release_coherent() should proceed with releasing memory from
224 int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
226 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
228 if (mem && vaddr >= mem->virt_base && vaddr <
229 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
230 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
233 spin_lock_irqsave(&mem->spinlock, flags);
234 bitmap_release_region(mem->bitmap, page, order);
235 spin_unlock_irqrestore(&mem->spinlock, flags);
240 EXPORT_SYMBOL(dma_release_from_coherent);
243 * dma_mmap_from_coherent() - try to mmap the memory allocated from
244 * per-device coherent memory pool to userspace
245 * @dev: device from which the memory was allocated
246 * @vma: vm_area for the userspace memory
247 * @vaddr: cpu address returned by dma_alloc_from_coherent
248 * @size: size of the memory buffer allocated by dma_alloc_from_coherent
249 * @ret: result from remap_pfn_range()
251 * This checks whether the memory was allocated from the per-device
252 * coherent memory pool and if so, maps that memory to the provided vma.
254 * Returns 1 if we correctly mapped the memory, or 0 if the caller should
255 * proceed with mapping memory from generic pools.
257 int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
258 void *vaddr, size_t size, int *ret)
260 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
262 if (mem && vaddr >= mem->virt_base && vaddr + size <=
263 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
264 unsigned long off = vma->vm_pgoff;
265 int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
266 int user_count = vma_pages(vma);
267 int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
270 if (off < count && user_count <= count - off) {
271 unsigned long pfn = mem->pfn_base + start + off;
272 *ret = remap_pfn_range(vma, vma->vm_start, pfn,
273 user_count << PAGE_SHIFT,
280 EXPORT_SYMBOL(dma_mmap_from_coherent);
283 * Support for reserved memory regions defined in device tree
285 #ifdef CONFIG_OF_RESERVED_MEM
286 #include <linux/of.h>
287 #include <linux/of_fdt.h>
288 #include <linux/of_reserved_mem.h>
290 static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
292 struct dma_coherent_mem *mem = rmem->priv;
295 !dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
296 DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
298 pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
299 &rmem->base, (unsigned long)rmem->size / SZ_1M);
303 dma_assign_coherent_memory(dev, mem);
307 static void rmem_dma_device_release(struct reserved_mem *rmem,
313 static const struct reserved_mem_ops rmem_dma_ops = {
314 .device_init = rmem_dma_device_init,
315 .device_release = rmem_dma_device_release,
318 static int __init rmem_dma_setup(struct reserved_mem *rmem)
320 unsigned long node = rmem->fdt_node;
322 if (of_get_flat_dt_prop(node, "reusable", NULL))
326 if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
327 pr_err("Reserved memory: regions without no-map are not yet supported\n");
332 rmem->ops = &rmem_dma_ops;
333 pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
334 &rmem->base, (unsigned long)rmem->size / SZ_1M);
337 RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);