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/dma-mapping.h> 8 9struct dma_coherent_mem { 10 void *virt_base; 11 dma_addr_t device_base; 12 int size; 13 int flags; 14 unsigned long *bitmap; 15}; 16 17int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr, 18 dma_addr_t device_addr, size_t size, int flags) 19{ 20 void __iomem *mem_base = NULL; 21 int pages = size >> PAGE_SHIFT; 22 int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long); 23 24 if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0) 25 goto out; 26 if (!size) 27 goto out; 28 if (dev->dma_mem) 29 goto out; 30 31 32 mem_base = ioremap(bus_addr, size); 33 if (!mem_base) 34 goto out; 35 36 dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL); 37 if (!dev->dma_mem) 38 goto out; 39 dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL); 40 if (!dev->dma_mem->bitmap) 41 goto free1_out; 42 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; 47 48 if (flags & DMA_MEMORY_MAP) 49 return DMA_MEMORY_MAP; 50 51 return DMA_MEMORY_IO; 52 53 free1_out: 54 kfree(dev->dma_mem); 55 out: 56 if (mem_base) 57 iounmap(mem_base); 58 return 0; 59} 60EXPORT_SYMBOL(dma_declare_coherent_memory); 61 62void dma_release_declared_memory(struct device *dev) 63{ 64 struct dma_coherent_mem *mem = dev->dma_mem; 65 66 if (!mem) 67 return; 68 dev->dma_mem = NULL; 69 iounmap(mem->virt_base); 70 kfree(mem->bitmap); 71 kfree(mem); 72} 73EXPORT_SYMBOL(dma_release_declared_memory); 74 75void *dma_mark_declared_memory_occupied(struct device *dev, 76 dma_addr_t device_addr, size_t size) 77{ 78 struct dma_coherent_mem *mem = dev->dma_mem; 79 int pos, err; 80 81 size += device_addr & ~PAGE_MASK; 82 83 if (!mem) 84 return ERR_PTR(-EINVAL); 85 86 pos = (device_addr - mem->device_base) >> PAGE_SHIFT; 87 err = bitmap_allocate_region(mem->bitmap, pos, get_order(size)); 88 if (err != 0) 89 return ERR_PTR(err); 90 return mem->virt_base + (pos << PAGE_SHIFT); 91} 92EXPORT_SYMBOL(dma_mark_declared_memory_occupied); 93 94/** 95 * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area 96 * 97 * @dev: device from which we allocate memory 98 * @size: size of requested memory area 99 * @dma_handle: This will be filled with the correct dma handle 100 * @ret: This pointer will be filled with the virtual address 101 * to allocated area. 102 * 103 * This function should be only called from per-arch dma_alloc_coherent() 104 * to support allocation from per-device coherent memory pools. 105 * 106 * Returns 0 if dma_alloc_coherent should continue with allocating from 107 * generic memory areas, or !0 if dma_alloc_coherent should return @ret. 108 */ 109int dma_alloc_from_coherent(struct device *dev, ssize_t size, 110 dma_addr_t *dma_handle, void **ret) 111{ 112 struct dma_coherent_mem *mem; 113 int order = get_order(size); 114 int pageno; 115 116 if (!dev) 117 return 0; 118 mem = dev->dma_mem; 119 if (!mem) 120 return 0; 121 122 *ret = NULL; 123 124 if (unlikely(size > (mem->size << PAGE_SHIFT))) 125 goto err; 126 127 pageno = bitmap_find_free_region(mem->bitmap, mem->size, order); 128 if (unlikely(pageno < 0)) 129 goto err; 130 131 /* 132 * Memory was found in the per-device area. 133 */ 134 *dma_handle = mem->device_base + (pageno << PAGE_SHIFT); 135 *ret = mem->virt_base + (pageno << PAGE_SHIFT); 136 memset(*ret, 0, size); 137 138 return 1; 139 140err: 141 /* 142 * In the case where the allocation can not be satisfied from the 143 * per-device area, try to fall back to generic memory if the 144 * constraints allow it. 145 */ 146 return mem->flags & DMA_MEMORY_EXCLUSIVE; 147} 148EXPORT_SYMBOL(dma_alloc_from_coherent); 149 150/** 151 * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool 152 * @dev: device from which the memory was allocated 153 * @order: the order of pages allocated 154 * @vaddr: virtual address of allocated pages 155 * 156 * This checks whether the memory was allocated from the per-device 157 * coherent memory pool and if so, releases that memory. 158 * 159 * Returns 1 if we correctly released the memory, or 0 if 160 * dma_release_coherent() should proceed with releasing memory from 161 * generic pools. 162 */ 163int dma_release_from_coherent(struct device *dev, int order, void *vaddr) 164{ 165 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; 166 167 if (mem && vaddr >= mem->virt_base && vaddr < 168 (mem->virt_base + (mem->size << PAGE_SHIFT))) { 169 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT; 170 171 bitmap_release_region(mem->bitmap, page, order); 172 return 1; 173 } 174 return 0; 175} 176EXPORT_SYMBOL(dma_release_from_coherent); 177