Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Dynamic DMA mapping support. |
| 3 | * |
| 4 | * On i386 there is no hardware dynamic DMA address translation, |
| 5 | * so consistent alloc/free are merely page allocation/freeing. |
| 6 | * The rest of the dynamic DMA mapping interface is implemented |
| 7 | * in asm/pci.h. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/types.h> |
| 11 | #include <linux/mm.h> |
| 12 | #include <linux/string.h> |
| 13 | #include <linux/pci.h> |
| 14 | #include <asm/io.h> |
| 15 | |
| 16 | struct dma_coherent_mem { |
| 17 | void *virt_base; |
| 18 | u32 device_base; |
| 19 | int size; |
| 20 | int flags; |
| 21 | unsigned long *bitmap; |
| 22 | }; |
| 23 | |
| 24 | void *dma_alloc_coherent(struct device *dev, size_t size, |
| 25 | dma_addr_t *dma_handle, unsigned int __nocast gfp) |
| 26 | { |
| 27 | void *ret; |
| 28 | struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; |
| 29 | int order = get_order(size); |
| 30 | /* ignore region specifiers */ |
| 31 | gfp &= ~(__GFP_DMA | __GFP_HIGHMEM); |
| 32 | |
| 33 | if (mem) { |
| 34 | int page = bitmap_find_free_region(mem->bitmap, mem->size, |
| 35 | order); |
| 36 | if (page >= 0) { |
| 37 | *dma_handle = mem->device_base + (page << PAGE_SHIFT); |
| 38 | ret = mem->virt_base + (page << PAGE_SHIFT); |
| 39 | memset(ret, 0, size); |
| 40 | return ret; |
| 41 | } |
| 42 | if (mem->flags & DMA_MEMORY_EXCLUSIVE) |
| 43 | return NULL; |
| 44 | } |
| 45 | |
| 46 | if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff)) |
| 47 | gfp |= GFP_DMA; |
| 48 | |
| 49 | ret = (void *)__get_free_pages(gfp, order); |
| 50 | |
| 51 | if (ret != NULL) { |
| 52 | memset(ret, 0, size); |
| 53 | *dma_handle = virt_to_phys(ret); |
| 54 | } |
| 55 | return ret; |
| 56 | } |
| 57 | |
| 58 | void dma_free_coherent(struct device *dev, size_t size, |
| 59 | void *vaddr, dma_addr_t dma_handle) |
| 60 | { |
| 61 | struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; |
| 62 | int order = get_order(size); |
| 63 | |
| 64 | if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) { |
| 65 | int page = (vaddr - mem->virt_base) >> PAGE_SHIFT; |
| 66 | |
| 67 | bitmap_release_region(mem->bitmap, page, order); |
| 68 | } else |
| 69 | free_pages((unsigned long)vaddr, order); |
| 70 | } |
| 71 | |
| 72 | int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr, |
| 73 | dma_addr_t device_addr, size_t size, int flags) |
| 74 | { |
| 75 | void __iomem *mem_base; |
| 76 | int pages = size >> PAGE_SHIFT; |
| 77 | int bitmap_size = (pages + 31)/32; |
| 78 | |
| 79 | if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0) |
| 80 | goto out; |
| 81 | if (!size) |
| 82 | goto out; |
| 83 | if (dev->dma_mem) |
| 84 | goto out; |
| 85 | |
| 86 | /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */ |
| 87 | |
| 88 | mem_base = ioremap(bus_addr, size); |
| 89 | if (!mem_base) |
| 90 | goto out; |
| 91 | |
| 92 | dev->dma_mem = kmalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL); |
| 93 | if (!dev->dma_mem) |
| 94 | goto out; |
| 95 | memset(dev->dma_mem, 0, sizeof(struct dma_coherent_mem)); |
| 96 | dev->dma_mem->bitmap = kmalloc(bitmap_size, GFP_KERNEL); |
| 97 | if (!dev->dma_mem->bitmap) |
| 98 | goto free1_out; |
| 99 | memset(dev->dma_mem->bitmap, 0, bitmap_size); |
| 100 | |
| 101 | dev->dma_mem->virt_base = mem_base; |
| 102 | dev->dma_mem->device_base = device_addr; |
| 103 | dev->dma_mem->size = pages; |
| 104 | dev->dma_mem->flags = flags; |
| 105 | |
| 106 | if (flags & DMA_MEMORY_MAP) |
| 107 | return DMA_MEMORY_MAP; |
| 108 | |
| 109 | return DMA_MEMORY_IO; |
| 110 | |
| 111 | free1_out: |
| 112 | kfree(dev->dma_mem->bitmap); |
| 113 | out: |
| 114 | return 0; |
| 115 | } |
| 116 | EXPORT_SYMBOL(dma_declare_coherent_memory); |
| 117 | |
| 118 | void dma_release_declared_memory(struct device *dev) |
| 119 | { |
| 120 | struct dma_coherent_mem *mem = dev->dma_mem; |
| 121 | |
| 122 | if(!mem) |
| 123 | return; |
| 124 | dev->dma_mem = NULL; |
| 125 | iounmap(mem->virt_base); |
| 126 | kfree(mem->bitmap); |
| 127 | kfree(mem); |
| 128 | } |
| 129 | EXPORT_SYMBOL(dma_release_declared_memory); |
| 130 | |
| 131 | void *dma_mark_declared_memory_occupied(struct device *dev, |
| 132 | dma_addr_t device_addr, size_t size) |
| 133 | { |
| 134 | struct dma_coherent_mem *mem = dev->dma_mem; |
| 135 | int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 136 | int pos, err; |
| 137 | |
| 138 | if (!mem) |
| 139 | return ERR_PTR(-EINVAL); |
| 140 | |
| 141 | pos = (device_addr - mem->device_base) >> PAGE_SHIFT; |
| 142 | err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages)); |
| 143 | if (err != 0) |
| 144 | return ERR_PTR(err); |
| 145 | return mem->virt_base + (pos << PAGE_SHIFT); |
| 146 | } |
| 147 | EXPORT_SYMBOL(dma_mark_declared_memory_occupied); |