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1616 | serge | 1 | /* |
2 | * DMA Pool allocator |
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3 | * |
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4 | * Copyright 2001 David Brownell |
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5 | * Copyright 2007 Intel Corporation |
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6 | * Author: Matthew Wilcox |
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7 | * |
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8 | * This software may be redistributed and/or modified under the terms of |
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9 | * the GNU General Public License ("GPL") version 2 as published by the |
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10 | * Free Software Foundation. |
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11 | * |
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12 | * This allocator returns small blocks of a given size which are DMA-able by |
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13 | * the given device. It uses the dma_alloc_coherent page allocator to get |
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14 | * new pages, then splits them up into blocks of the required size. |
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15 | * Many older drivers still have their own code to do this. |
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16 | * |
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17 | * The current design of this allocator is fairly simple. The pool is |
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18 | * represented by the 'struct dma_pool' which keeps a doubly-linked list of |
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19 | * allocated pages. Each page in the page_list is split into blocks of at |
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20 | * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked |
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21 | * list of free blocks within the page. Used blocks aren't tracked, but we |
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22 | * keep a count of how many are currently allocated from each page. |
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23 | */ |
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24 | |||
6295 | serge | 25 | #include |
26 | #include |
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27 | #include |
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28 | #include |
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29 | #include |
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1616 | serge | 30 | |
5270 | serge | 31 | #include |
6295 | serge | 32 | #include |
33 | #include |
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34 | |||
1616 | serge | 35 | #include |
5270 | serge | 36 | #include |
1616 | serge | 37 | #include |
38 | |||
39 | |||
40 | struct dma_pool { /* the pool */ |
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41 | struct list_head page_list; |
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6295 | serge | 42 | spinlock_t lock; |
43 | size_t size; |
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44 | struct device *dev; |
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1616 | serge | 45 | size_t allocation; |
46 | size_t boundary; |
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6295 | serge | 47 | char name[32]; |
1616 | serge | 48 | struct list_head pools; |
49 | }; |
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50 | |||
51 | struct dma_page { /* cacheable header for 'allocation' bytes */ |
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52 | struct list_head page_list; |
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53 | void *vaddr; |
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54 | dma_addr_t dma; |
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55 | unsigned int in_use; |
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56 | unsigned int offset; |
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57 | }; |
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58 | |||
59 | static DEFINE_MUTEX(pools_lock); |
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6295 | serge | 60 | static DEFINE_MUTEX(pools_reg_lock); |
1616 | serge | 61 | |
62 | |||
6295 | serge | 63 | |
64 | |||
1616 | serge | 65 | /** |
66 | * dma_pool_create - Creates a pool of consistent memory blocks, for dma. |
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67 | * @name: name of pool, for diagnostics |
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68 | * @dev: device that will be doing the DMA |
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69 | * @size: size of the blocks in this pool. |
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70 | * @align: alignment requirement for blocks; must be a power of two |
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71 | * @boundary: returned blocks won't cross this power of two boundary |
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72 | * Context: !in_interrupt() |
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73 | * |
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74 | * Returns a dma allocation pool with the requested characteristics, or |
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75 | * null if one can't be created. Given one of these pools, dma_pool_alloc() |
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76 | * may be used to allocate memory. Such memory will all have "consistent" |
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77 | * DMA mappings, accessible by the device and its driver without using |
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78 | * cache flushing primitives. The actual size of blocks allocated may be |
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79 | * larger than requested because of alignment. |
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80 | * |
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81 | * If @boundary is nonzero, objects returned from dma_pool_alloc() won't |
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82 | * cross that size boundary. This is useful for devices which have |
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83 | * addressing restrictions on individual DMA transfers, such as not crossing |
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84 | * boundaries of 4KBytes. |
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85 | */ |
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86 | struct dma_pool *dma_pool_create(const char *name, struct device *dev, |
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6295 | serge | 87 | size_t size, size_t align, size_t boundary) |
1616 | serge | 88 | { |
6295 | serge | 89 | struct dma_pool *retval; |
90 | size_t allocation; |
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91 | bool empty = false; |
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1616 | serge | 92 | |
6295 | serge | 93 | if (align == 0) |
94 | align = 1; |
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95 | else if (align & (align - 1)) |
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96 | return NULL; |
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1616 | serge | 97 | |
6295 | serge | 98 | if (size == 0) |
99 | return NULL; |
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100 | else if (size < 4) |
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101 | size = 4; |
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1616 | serge | 102 | |
6295 | serge | 103 | if ((size % align) != 0) |
104 | size = ALIGN(size, align); |
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1616 | serge | 105 | |
6295 | serge | 106 | allocation = max_t(size_t, size, PAGE_SIZE); |
1616 | serge | 107 | |
108 | allocation = (allocation+0x7FFF) & ~0x7FFF; |
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109 | |||
6295 | serge | 110 | if (!boundary) |
111 | boundary = allocation; |
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112 | else if ((boundary < size) || (boundary & (boundary - 1))) |
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113 | return NULL; |
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1616 | serge | 114 | |
115 | retval = kmalloc(sizeof(*retval), GFP_KERNEL); |
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116 | |||
117 | if (!retval) |
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118 | return retval; |
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119 | |||
6295 | serge | 120 | strlcpy(retval->name, name, sizeof(retval->name)); |
1616 | serge | 121 | |
6295 | serge | 122 | retval->dev = dev; |
1616 | serge | 123 | |
6295 | serge | 124 | INIT_LIST_HEAD(&retval->page_list); |
125 | spin_lock_init(&retval->lock); |
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1616 | serge | 126 | retval->size = size; |
127 | retval->boundary = boundary; |
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128 | retval->allocation = allocation; |
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129 | |||
130 | INIT_LIST_HEAD(&retval->pools); |
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131 | |||
132 | return retval; |
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133 | } |
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134 | |||
135 | static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) |
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136 | { |
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137 | unsigned int offset = 0; |
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138 | unsigned int next_boundary = pool->boundary; |
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139 | |||
140 | do { |
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141 | unsigned int next = offset + pool->size; |
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142 | if (unlikely((next + pool->size) >= next_boundary)) { |
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143 | next = next_boundary; |
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144 | next_boundary += pool->boundary; |
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145 | } |
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146 | *(int *)(page->vaddr + offset) = next; |
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147 | offset = next; |
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148 | } while (offset < pool->allocation); |
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149 | } |
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150 | |||
6295 | serge | 151 | static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) |
1616 | serge | 152 | { |
153 | struct dma_page *page; |
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154 | |||
6295 | serge | 155 | page = kmalloc(sizeof(*page), mem_flags); |
156 | if (!page) |
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157 | return NULL; |
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1616 | serge | 158 | page->vaddr = (void*)KernelAlloc(pool->allocation); |
159 | |||
160 | dbgprintf("%s 0x%0x ",__FUNCTION__, page->vaddr); |
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161 | |||
6295 | serge | 162 | if (page->vaddr) { |
163 | #ifdef DMAPOOL_DEBUG |
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164 | memset(page->vaddr, POOL_POISON_FREED, pool->allocation); |
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165 | #endif |
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166 | |||
1616 | serge | 167 | page->dma = GetPgAddr(page->vaddr); |
168 | |||
169 | dbgprintf("dma 0x%0x\n", page->dma); |
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170 | |||
171 | pool_initialise_page(pool, page); |
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172 | page->in_use = 0; |
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173 | page->offset = 0; |
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174 | } else { |
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6295 | serge | 175 | kfree(page); |
1616 | serge | 176 | page = NULL; |
177 | } |
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178 | return page; |
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179 | } |
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180 | |||
6295 | serge | 181 | static inline bool is_page_busy(struct dma_page *page) |
1616 | serge | 182 | { |
6295 | serge | 183 | return page->in_use != 0; |
1616 | serge | 184 | } |
185 | |||
186 | static void pool_free_page(struct dma_pool *pool, struct dma_page *page) |
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187 | { |
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6295 | serge | 188 | dma_addr_t dma = page->dma; |
1616 | serge | 189 | |
6295 | serge | 190 | #ifdef DMAPOOL_DEBUG |
191 | memset(page->vaddr, POOL_POISON_FREED, pool->allocation); |
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192 | #endif |
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193 | |||
1616 | serge | 194 | KernelFree(page->vaddr); |
6295 | serge | 195 | list_del(&page->page_list); |
196 | kfree(page); |
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1616 | serge | 197 | } |
198 | |||
199 | /** |
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200 | * dma_pool_destroy - destroys a pool of dma memory blocks. |
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201 | * @pool: dma pool that will be destroyed |
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202 | * Context: !in_interrupt() |
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203 | * |
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204 | * Caller guarantees that no more memory from the pool is in use, |
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205 | * and that nothing will try to use the pool after this call. |
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206 | */ |
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207 | void dma_pool_destroy(struct dma_pool *pool) |
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208 | { |
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6295 | serge | 209 | bool empty = false; |
210 | |||
211 | if (unlikely(!pool)) |
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212 | return; |
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213 | |||
214 | mutex_lock(&pools_reg_lock); |
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1616 | serge | 215 | mutex_lock(&pools_lock); |
216 | list_del(&pool->pools); |
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217 | mutex_unlock(&pools_lock); |
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218 | |||
6295 | serge | 219 | mutex_unlock(&pools_reg_lock); |
220 | |||
1616 | serge | 221 | while (!list_empty(&pool->page_list)) { |
222 | struct dma_page *page; |
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223 | page = list_entry(pool->page_list.next, |
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224 | struct dma_page, page_list); |
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6295 | serge | 225 | if (is_page_busy(page)) { |
1616 | serge | 226 | printk(KERN_ERR "dma_pool_destroy %p busy\n", |
227 | page->vaddr); |
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228 | /* leak the still-in-use consistent memory */ |
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229 | list_del(&page->page_list); |
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230 | kfree(page); |
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231 | } else |
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232 | pool_free_page(pool, page); |
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233 | } |
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234 | |||
235 | kfree(pool); |
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236 | } |
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6295 | serge | 237 | EXPORT_SYMBOL(dma_pool_destroy); |
1616 | serge | 238 | |
239 | /** |
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240 | * dma_pool_alloc - get a block of consistent memory |
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241 | * @pool: dma pool that will produce the block |
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242 | * @mem_flags: GFP_* bitmask |
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243 | * @handle: pointer to dma address of block |
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244 | * |
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245 | * This returns the kernel virtual address of a currently unused block, |
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246 | * and reports its dma address through the handle. |
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247 | * If such a memory block can't be allocated, %NULL is returned. |
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248 | */ |
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249 | void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, |
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250 | dma_addr_t *handle) |
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251 | { |
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6295 | serge | 252 | unsigned long flags; |
1616 | serge | 253 | struct dma_page *page; |
254 | size_t offset; |
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255 | void *retval; |
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256 | |||
6295 | serge | 257 | |
258 | spin_lock_irqsave(&pool->lock, flags); |
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1616 | serge | 259 | list_for_each_entry(page, &pool->page_list, page_list) { |
260 | if (page->offset < pool->allocation) |
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261 | goto ready; |
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262 | } |
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6295 | serge | 263 | |
264 | /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */ |
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265 | spin_unlock_irqrestore(&pool->lock, flags); |
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266 | |||
267 | page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); |
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1616 | serge | 268 | if (!page) |
6295 | serge | 269 | return NULL; |
1616 | serge | 270 | |
6295 | serge | 271 | spin_lock_irqsave(&pool->lock, flags); |
272 | |||
273 | list_add(&page->page_list, &pool->page_list); |
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1616 | serge | 274 | ready: |
6295 | serge | 275 | page->in_use++; |
1616 | serge | 276 | offset = page->offset; |
277 | page->offset = *(int *)(page->vaddr + offset); |
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278 | retval = offset + page->vaddr; |
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6295 | serge | 279 | *handle = offset + page->dma; |
280 | #ifdef DMAPOOL_DEBUG |
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281 | { |
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282 | int i; |
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283 | u8 *data = retval; |
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284 | /* page->offset is stored in first 4 bytes */ |
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285 | for (i = sizeof(page->offset); i < pool->size; i++) { |
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286 | if (data[i] == POOL_POISON_FREED) |
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287 | continue; |
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288 | if (pool->dev) |
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289 | dev_err(pool->dev, |
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290 | "dma_pool_alloc %s, %p (corrupted)\n", |
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291 | pool->name, retval); |
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292 | else |
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293 | pr_err("dma_pool_alloc %s, %p (corrupted)\n", |
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294 | pool->name, retval); |
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295 | |||
296 | /* |
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297 | * Dump the first 4 bytes even if they are not |
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298 | * POOL_POISON_FREED |
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299 | */ |
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300 | print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, |
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301 | data, pool->size, 1); |
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302 | break; |
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303 | } |
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304 | } |
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305 | if (!(mem_flags & __GFP_ZERO)) |
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306 | memset(retval, POOL_POISON_ALLOCATED, pool->size); |
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307 | #endif |
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308 | spin_unlock_irqrestore(&pool->lock, flags); |
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309 | |||
310 | if (mem_flags & __GFP_ZERO) |
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311 | memset(retval, 0, pool->size); |
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312 | |||
1616 | serge | 313 | return retval; |
314 | } |
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6295 | serge | 315 | EXPORT_SYMBOL(dma_pool_alloc); |
1616 | serge | 316 | |
317 | static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) |
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318 | { |
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319 | struct dma_page *page; |
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320 | |||
321 | list_for_each_entry(page, &pool->page_list, page_list) { |
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322 | if (dma < page->dma) |
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323 | continue; |
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6295 | serge | 324 | if ((dma - page->dma) < pool->allocation) |
325 | return page; |
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1616 | serge | 326 | } |
6295 | serge | 327 | return NULL; |
1616 | serge | 328 | } |
329 | |||
330 | /** |
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331 | * dma_pool_free - put block back into dma pool |
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332 | * @pool: the dma pool holding the block |
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333 | * @vaddr: virtual address of block |
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334 | * @dma: dma address of block |
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335 | * |
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336 | * Caller promises neither device nor driver will again touch this block |
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337 | * unless it is first re-allocated. |
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338 | */ |
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339 | void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) |
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340 | { |
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341 | struct dma_page *page; |
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342 | unsigned long flags; |
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343 | unsigned int offset; |
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344 | |||
6295 | serge | 345 | spin_lock_irqsave(&pool->lock, flags); |
1616 | serge | 346 | page = pool_find_page(pool, dma); |
347 | if (!page) { |
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6295 | serge | 348 | spin_unlock_irqrestore(&pool->lock, flags); |
349 | printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n", |
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350 | pool->name, vaddr, (unsigned long)dma); |
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1616 | serge | 351 | return; |
352 | } |
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353 | |||
354 | offset = vaddr - page->vaddr; |
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6295 | serge | 355 | #ifdef DMAPOOL_DEBUG |
356 | if ((dma - page->dma) != offset) { |
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357 | spin_unlock_irqrestore(&pool->lock, flags); |
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358 | if (pool->dev) |
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359 | dev_err(pool->dev, |
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360 | "dma_pool_free %s, %p (bad vaddr)/%Lx\n", |
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361 | pool->name, vaddr, (unsigned long long)dma); |
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362 | else |
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363 | printk(KERN_ERR |
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364 | "dma_pool_free %s, %p (bad vaddr)/%Lx\n", |
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365 | pool->name, vaddr, (unsigned long long)dma); |
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366 | return; |
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367 | } |
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368 | { |
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369 | unsigned int chain = page->offset; |
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370 | while (chain < pool->allocation) { |
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371 | if (chain != offset) { |
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372 | chain = *(int *)(page->vaddr + chain); |
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373 | continue; |
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374 | } |
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375 | spin_unlock_irqrestore(&pool->lock, flags); |
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376 | if (pool->dev) |
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377 | dev_err(pool->dev, "dma_pool_free %s, dma %Lx " |
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378 | "already free\n", pool->name, |
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379 | (unsigned long long)dma); |
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380 | else |
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381 | printk(KERN_ERR "dma_pool_free %s, dma %Lx " |
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382 | "already free\n", pool->name, |
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383 | (unsigned long long)dma); |
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384 | return; |
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385 | } |
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386 | } |
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387 | memset(vaddr, POOL_POISON_FREED, pool->size); |
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388 | #endif |
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1616 | serge | 389 | |
6295 | serge | 390 | page->in_use--; |
391 | *(int *)vaddr = page->offset; |
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392 | page->offset = offset; |
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1616 | serge | 393 | /* |
394 | * Resist a temptation to do |
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395 | * if (!is_page_busy(page)) pool_free_page(pool, page); |
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396 | * Better have a few empty pages hang around. |
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397 | */ |
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6295 | serge | 398 | spin_unlock_irqrestore(&pool->lock, flags); |
1616 | serge | 399 | } |
6295 | serge | 400 | EXPORT_SYMBOL(dma_pool_free); |
1616 | serge | 401 | |
6295 | serge | 402 | /* |
403 | * Managed DMA pool |
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404 | */ |
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405 | static void dmam_pool_release(struct device *dev, void *res) |
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406 | { |
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407 | struct dma_pool *pool = *(struct dma_pool **)res; |
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408 | |||
409 | dma_pool_destroy(pool); |
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410 | } |
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411 | |||
412 | static int dmam_pool_match(struct device *dev, void *res, void *match_data) |
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413 | { |
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414 | return *(struct dma_pool **)res == match_data; |
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415 | }>>>>>>>> |
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416 |