2 * Coherent per-device memory handling.
5 #include <linux/kernel.h>
6 #include <linux/dma-mapping.h>
8 struct dma_coherent_mem {
13 unsigned long *bitmap;
16 int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
17 dma_addr_t device_addr, size_t size, int flags)
19 void __iomem *mem_base = NULL;
20 int pages = size >> PAGE_SHIFT;
21 int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
23 if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
30 /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
32 mem_base = ioremap(bus_addr, size);
36 dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
39 dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
40 if (!dev->dma_mem->bitmap)
43 dev->dma_mem->virt_base = mem_base;
44 dev->dma_mem->device_base = device_addr;
45 dev->dma_mem->size = pages;
46 dev->dma_mem->flags = flags;
48 if (flags & DMA_MEMORY_MAP)
49 return DMA_MEMORY_MAP;
60 EXPORT_SYMBOL(dma_declare_coherent_memory);
62 void dma_release_declared_memory(struct device *dev)
64 struct dma_coherent_mem *mem = dev->dma_mem;
69 iounmap(mem->virt_base);
73 EXPORT_SYMBOL(dma_release_declared_memory);
75 void *dma_mark_declared_memory_occupied(struct device *dev,
76 dma_addr_t device_addr, size_t size)
78 struct dma_coherent_mem *mem = dev->dma_mem;
80 int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1);
85 return ERR_PTR(-EINVAL);
87 pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
88 err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
91 return mem->virt_base + (pos << PAGE_SHIFT);
93 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
95 int dma_alloc_from_coherent(struct device *dev, ssize_t size,
96 dma_addr_t *dma_handle, void **ret)
98 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
99 int order = get_order(size);
102 int page = bitmap_find_free_region(mem->bitmap, mem->size,
105 *dma_handle = mem->device_base + (page << PAGE_SHIFT);
106 *ret = mem->virt_base + (page << PAGE_SHIFT);
107 memset(*ret, 0, size);
108 } else if (mem->flags & DMA_MEMORY_EXCLUSIVE)
111 return (mem != NULL);
114 int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
116 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
118 if (mem && vaddr >= mem->virt_base && vaddr <
119 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
120 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
122 bitmap_release_region(mem->bitmap, page, order);