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;
19 bool use_dev_dma_pfn_offset;
22 static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
24 static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
26 if (dev && dev->dma_mem)
31 static inline dma_addr_t dma_get_device_base(struct device *dev,
32 struct dma_coherent_mem * mem)
34 if (mem->use_dev_dma_pfn_offset)
35 return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
37 return mem->device_base;
40 static bool 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)
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);
49 if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
54 if (flags & DMA_MEMORY_MAP)
55 mem_base = memremap(phys_addr, size, MEMREMAP_WC);
57 mem_base = ioremap(phys_addr, size);
61 dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
64 dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
68 dma_mem->virt_base = mem_base;
69 dma_mem->device_base = device_addr;
70 dma_mem->pfn_base = PFN_DOWN(phys_addr);
71 dma_mem->size = pages;
72 dma_mem->flags = flags;
73 spin_lock_init(&dma_mem->spinlock);
81 if (flags & DMA_MEMORY_MAP)
89 static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
94 if (mem->flags & DMA_MEMORY_MAP)
95 memunmap(mem->virt_base);
97 iounmap(mem->virt_base);
102 static int dma_assign_coherent_memory(struct device *dev,
103 struct dma_coherent_mem *mem)
112 /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
117 int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
118 dma_addr_t device_addr, size_t size, int flags)
120 struct dma_coherent_mem *mem;
122 if (!dma_init_coherent_memory(phys_addr, device_addr, size, flags,
126 if (dma_assign_coherent_memory(dev, mem) == 0)
127 return flags & DMA_MEMORY_MAP ? DMA_MEMORY_MAP : DMA_MEMORY_IO;
129 dma_release_coherent_memory(mem);
132 EXPORT_SYMBOL(dma_declare_coherent_memory);
134 void dma_release_declared_memory(struct device *dev)
136 struct dma_coherent_mem *mem = dev->dma_mem;
140 dma_release_coherent_memory(mem);
143 EXPORT_SYMBOL(dma_release_declared_memory);
145 void *dma_mark_declared_memory_occupied(struct device *dev,
146 dma_addr_t device_addr, size_t size)
148 struct dma_coherent_mem *mem = dev->dma_mem;
152 size += device_addr & ~PAGE_MASK;
155 return ERR_PTR(-EINVAL);
157 spin_lock_irqsave(&mem->spinlock, flags);
158 pos = PFN_DOWN(device_addr - dma_get_device_base(dev, mem));
159 err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
160 spin_unlock_irqrestore(&mem->spinlock, flags);
164 return mem->virt_base + (pos << PAGE_SHIFT);
166 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
168 static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
169 ssize_t size, dma_addr_t *dma_handle)
171 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 coherent 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);
206 * dma_alloc_from_dev_coherent() - allocate memory from device coherent pool
207 * @dev: device from which we allocate memory
208 * @size: size of requested memory area
209 * @dma_handle: This will be filled with the correct dma handle
210 * @ret: This pointer will be filled with the virtual address
213 * This function should be only called from per-arch dma_alloc_coherent()
214 * to support allocation from per-device coherent memory pools.
216 * Returns 0 if dma_alloc_coherent should continue with allocating from
217 * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
219 int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
220 dma_addr_t *dma_handle, void **ret)
222 struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
227 *ret = __dma_alloc_from_coherent(mem, size, dma_handle);
232 * In the case where the allocation can not be satisfied from the
233 * per-device area, try to fall back to generic memory if the
234 * constraints allow it.
236 return mem->flags & DMA_MEMORY_EXCLUSIVE;
238 EXPORT_SYMBOL(dma_alloc_from_dev_coherent);
240 void *dma_alloc_from_global_coherent(ssize_t size, dma_addr_t *dma_handle)
242 if (!dma_coherent_default_memory)
245 return __dma_alloc_from_coherent(dma_coherent_default_memory, size,
249 static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
250 int order, void *vaddr)
252 if (mem && vaddr >= mem->virt_base && vaddr <
253 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
254 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
257 spin_lock_irqsave(&mem->spinlock, flags);
258 bitmap_release_region(mem->bitmap, page, order);
259 spin_unlock_irqrestore(&mem->spinlock, flags);
266 * dma_release_from_dev_coherent() - free memory to device coherent memory pool
267 * @dev: device from which the memory was allocated
268 * @order: the order of pages allocated
269 * @vaddr: virtual address of allocated pages
271 * This checks whether the memory was allocated from the per-device
272 * coherent memory pool and if so, releases that memory.
274 * Returns 1 if we correctly released the memory, or 0 if the caller should
275 * proceed with releasing memory from generic pools.
277 int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
279 struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
281 return __dma_release_from_coherent(mem, order, vaddr);
283 EXPORT_SYMBOL(dma_release_from_dev_coherent);
285 int dma_release_from_global_coherent(int order, void *vaddr)
287 if (!dma_coherent_default_memory)
290 return __dma_release_from_coherent(dma_coherent_default_memory, order,
294 static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
295 struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
297 if (mem && vaddr >= mem->virt_base && vaddr + size <=
298 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
299 unsigned long off = vma->vm_pgoff;
300 int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
301 int user_count = vma_pages(vma);
302 int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
305 if (off < count && user_count <= count - off) {
306 unsigned long pfn = mem->pfn_base + start + off;
307 *ret = remap_pfn_range(vma, vma->vm_start, pfn,
308 user_count << PAGE_SHIFT,
317 * dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
318 * @dev: device from which the memory was allocated
319 * @vma: vm_area for the userspace memory
320 * @vaddr: cpu address returned by dma_alloc_from_dev_coherent
321 * @size: size of the memory buffer allocated
322 * @ret: result from remap_pfn_range()
324 * This checks whether the memory was allocated from the per-device
325 * coherent memory pool and if so, maps that memory to the provided vma.
327 * Returns 1 if we correctly mapped the memory, or 0 if the caller should
328 * proceed with mapping memory from generic pools.
330 int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
331 void *vaddr, size_t size, int *ret)
333 struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
335 return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
337 EXPORT_SYMBOL(dma_mmap_from_dev_coherent);
339 int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
340 size_t size, int *ret)
342 if (!dma_coherent_default_memory)
345 return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
350 * Support for reserved memory regions defined in device tree
352 #ifdef CONFIG_OF_RESERVED_MEM
353 #include <linux/of.h>
354 #include <linux/of_fdt.h>
355 #include <linux/of_reserved_mem.h>
357 static struct reserved_mem *dma_reserved_default_memory __initdata;
359 static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
361 struct dma_coherent_mem *mem = rmem->priv;
364 !dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
365 DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
367 pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
368 &rmem->base, (unsigned long)rmem->size / SZ_1M);
371 mem->use_dev_dma_pfn_offset = true;
373 dma_assign_coherent_memory(dev, mem);
377 static void rmem_dma_device_release(struct reserved_mem *rmem,
384 static const struct reserved_mem_ops rmem_dma_ops = {
385 .device_init = rmem_dma_device_init,
386 .device_release = rmem_dma_device_release,
389 static int __init rmem_dma_setup(struct reserved_mem *rmem)
391 unsigned long node = rmem->fdt_node;
393 if (of_get_flat_dt_prop(node, "reusable", NULL))
397 if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
398 pr_err("Reserved memory: regions without no-map are not yet supported\n");
402 if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
403 WARN(dma_reserved_default_memory,
404 "Reserved memory: region for default DMA coherent area is redefined\n");
405 dma_reserved_default_memory = rmem;
409 rmem->ops = &rmem_dma_ops;
410 pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
411 &rmem->base, (unsigned long)rmem->size / SZ_1M);
415 static int __init dma_init_reserved_memory(void)
417 const struct reserved_mem_ops *ops;
420 if (!dma_reserved_default_memory)
423 ops = dma_reserved_default_memory->ops;
426 * We rely on rmem_dma_device_init() does not propagate error of
427 * dma_assign_coherent_memory() for "NULL" device.
429 ret = ops->device_init(dma_reserved_default_memory, NULL);
432 dma_coherent_default_memory = dma_reserved_default_memory->priv;
433 pr_info("DMA: default coherent area is set\n");
439 core_initcall(dma_init_reserved_memory);
441 RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);