]>
Commit | Line | Data |
---|---|---|
1 | /* | |
2 | * DMA Pool allocator | |
3 | * | |
4 | * Copyright 2001 David Brownell | |
5 | * Copyright 2007 Intel Corporation | |
6 | * Author: Matthew Wilcox <willy@linux.intel.com> | |
7 | * | |
8 | * This software may be redistributed and/or modified under the terms of | |
9 | * the GNU General Public License ("GPL") version 2 as published by the | |
10 | * Free Software Foundation. | |
11 | * | |
12 | * This allocator returns small blocks of a given size which are DMA-able by | |
13 | * the given device. It uses the dma_alloc_coherent page allocator to get | |
14 | * new pages, then splits them up into blocks of the required size. | |
15 | * Many older drivers still have their own code to do this. | |
16 | * | |
17 | * The current design of this allocator is fairly simple. The pool is | |
18 | * represented by the 'struct dma_pool' which keeps a doubly-linked list of | |
19 | * allocated pages. Each page in the page_list is split into blocks of at | |
20 | * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked | |
21 | * list of free blocks within the page. Used blocks aren't tracked, but we | |
22 | * keep a count of how many are currently allocated from each page. | |
23 | */ | |
24 | ||
25 | #include <linux/device.h> | |
26 | #include <linux/dma-mapping.h> | |
27 | #include <linux/dmapool.h> | |
28 | #include <linux/kernel.h> | |
29 | #include <linux/list.h> | |
30 | #include <linux/export.h> | |
31 | #include <linux/mutex.h> | |
32 | #include <linux/poison.h> | |
33 | #include <linux/sched.h> | |
34 | #include <linux/slab.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/string.h> | |
37 | #include <linux/types.h> | |
38 | #include <linux/wait.h> | |
39 | ||
40 | #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON) | |
41 | #define DMAPOOL_DEBUG 1 | |
42 | #endif | |
43 | ||
44 | struct dma_pool { /* the pool */ | |
45 | struct list_head page_list; | |
46 | spinlock_t lock; | |
47 | size_t size; | |
48 | struct device *dev; | |
49 | size_t allocation; | |
50 | size_t boundary; | |
51 | char name[32]; | |
52 | wait_queue_head_t waitq; | |
53 | struct list_head pools; | |
54 | }; | |
55 | ||
56 | struct dma_page { /* cacheable header for 'allocation' bytes */ | |
57 | struct list_head page_list; | |
58 | void *vaddr; | |
59 | dma_addr_t dma; | |
60 | unsigned int in_use; | |
61 | unsigned int offset; | |
62 | }; | |
63 | ||
64 | #define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000) | |
65 | ||
66 | static DEFINE_MUTEX(pools_lock); | |
67 | ||
68 | static ssize_t | |
69 | show_pools(struct device *dev, struct device_attribute *attr, char *buf) | |
70 | { | |
71 | unsigned temp; | |
72 | unsigned size; | |
73 | char *next; | |
74 | struct dma_page *page; | |
75 | struct dma_pool *pool; | |
76 | ||
77 | next = buf; | |
78 | size = PAGE_SIZE; | |
79 | ||
80 | temp = scnprintf(next, size, "poolinfo - 0.1\n"); | |
81 | size -= temp; | |
82 | next += temp; | |
83 | ||
84 | mutex_lock(&pools_lock); | |
85 | list_for_each_entry(pool, &dev->dma_pools, pools) { | |
86 | unsigned pages = 0; | |
87 | unsigned blocks = 0; | |
88 | ||
89 | spin_lock_irq(&pool->lock); | |
90 | list_for_each_entry(page, &pool->page_list, page_list) { | |
91 | pages++; | |
92 | blocks += page->in_use; | |
93 | } | |
94 | spin_unlock_irq(&pool->lock); | |
95 | ||
96 | /* per-pool info, no real statistics yet */ | |
97 | temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n", | |
98 | pool->name, blocks, | |
99 | pages * (pool->allocation / pool->size), | |
100 | pool->size, pages); | |
101 | size -= temp; | |
102 | next += temp; | |
103 | } | |
104 | mutex_unlock(&pools_lock); | |
105 | ||
106 | return PAGE_SIZE - size; | |
107 | } | |
108 | ||
109 | static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL); | |
110 | ||
111 | /** | |
112 | * dma_pool_create - Creates a pool of consistent memory blocks, for dma. | |
113 | * @name: name of pool, for diagnostics | |
114 | * @dev: device that will be doing the DMA | |
115 | * @size: size of the blocks in this pool. | |
116 | * @align: alignment requirement for blocks; must be a power of two | |
117 | * @boundary: returned blocks won't cross this power of two boundary | |
118 | * Context: !in_interrupt() | |
119 | * | |
120 | * Returns a dma allocation pool with the requested characteristics, or | |
121 | * null if one can't be created. Given one of these pools, dma_pool_alloc() | |
122 | * may be used to allocate memory. Such memory will all have "consistent" | |
123 | * DMA mappings, accessible by the device and its driver without using | |
124 | * cache flushing primitives. The actual size of blocks allocated may be | |
125 | * larger than requested because of alignment. | |
126 | * | |
127 | * If @boundary is nonzero, objects returned from dma_pool_alloc() won't | |
128 | * cross that size boundary. This is useful for devices which have | |
129 | * addressing restrictions on individual DMA transfers, such as not crossing | |
130 | * boundaries of 4KBytes. | |
131 | */ | |
132 | struct dma_pool *dma_pool_create(const char *name, struct device *dev, | |
133 | size_t size, size_t align, size_t boundary) | |
134 | { | |
135 | struct dma_pool *retval; | |
136 | size_t allocation; | |
137 | ||
138 | if (align == 0) { | |
139 | align = 1; | |
140 | } else if (align & (align - 1)) { | |
141 | return NULL; | |
142 | } | |
143 | ||
144 | if (size == 0) { | |
145 | return NULL; | |
146 | } else if (size < 4) { | |
147 | size = 4; | |
148 | } | |
149 | ||
150 | if ((size % align) != 0) | |
151 | size = ALIGN(size, align); | |
152 | ||
153 | allocation = max_t(size_t, size, PAGE_SIZE); | |
154 | ||
155 | if (!boundary) { | |
156 | boundary = allocation; | |
157 | } else if ((boundary < size) || (boundary & (boundary - 1))) { | |
158 | return NULL; | |
159 | } | |
160 | ||
161 | retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev)); | |
162 | if (!retval) | |
163 | return retval; | |
164 | ||
165 | strlcpy(retval->name, name, sizeof(retval->name)); | |
166 | ||
167 | retval->dev = dev; | |
168 | ||
169 | INIT_LIST_HEAD(&retval->page_list); | |
170 | spin_lock_init(&retval->lock); | |
171 | retval->size = size; | |
172 | retval->boundary = boundary; | |
173 | retval->allocation = allocation; | |
174 | init_waitqueue_head(&retval->waitq); | |
175 | ||
176 | if (dev) { | |
177 | int ret; | |
178 | ||
179 | mutex_lock(&pools_lock); | |
180 | if (list_empty(&dev->dma_pools)) | |
181 | ret = device_create_file(dev, &dev_attr_pools); | |
182 | else | |
183 | ret = 0; | |
184 | /* note: not currently insisting "name" be unique */ | |
185 | if (!ret) | |
186 | list_add(&retval->pools, &dev->dma_pools); | |
187 | else { | |
188 | kfree(retval); | |
189 | retval = NULL; | |
190 | } | |
191 | mutex_unlock(&pools_lock); | |
192 | } else | |
193 | INIT_LIST_HEAD(&retval->pools); | |
194 | ||
195 | return retval; | |
196 | } | |
197 | EXPORT_SYMBOL(dma_pool_create); | |
198 | ||
199 | static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) | |
200 | { | |
201 | unsigned int offset = 0; | |
202 | unsigned int next_boundary = pool->boundary; | |
203 | ||
204 | do { | |
205 | unsigned int next = offset + pool->size; | |
206 | if (unlikely((next + pool->size) >= next_boundary)) { | |
207 | next = next_boundary; | |
208 | next_boundary += pool->boundary; | |
209 | } | |
210 | *(int *)(page->vaddr + offset) = next; | |
211 | offset = next; | |
212 | } while (offset < pool->allocation); | |
213 | } | |
214 | ||
215 | static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) | |
216 | { | |
217 | struct dma_page *page; | |
218 | ||
219 | page = kmalloc(sizeof(*page), mem_flags); | |
220 | if (!page) | |
221 | return NULL; | |
222 | page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, | |
223 | &page->dma, mem_flags); | |
224 | if (page->vaddr) { | |
225 | #ifdef DMAPOOL_DEBUG | |
226 | memset(page->vaddr, POOL_POISON_FREED, pool->allocation); | |
227 | #endif | |
228 | pool_initialise_page(pool, page); | |
229 | list_add(&page->page_list, &pool->page_list); | |
230 | page->in_use = 0; | |
231 | page->offset = 0; | |
232 | } else { | |
233 | kfree(page); | |
234 | page = NULL; | |
235 | } | |
236 | return page; | |
237 | } | |
238 | ||
239 | static inline int is_page_busy(struct dma_page *page) | |
240 | { | |
241 | return page->in_use != 0; | |
242 | } | |
243 | ||
244 | static void pool_free_page(struct dma_pool *pool, struct dma_page *page) | |
245 | { | |
246 | dma_addr_t dma = page->dma; | |
247 | ||
248 | #ifdef DMAPOOL_DEBUG | |
249 | memset(page->vaddr, POOL_POISON_FREED, pool->allocation); | |
250 | #endif | |
251 | dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma); | |
252 | list_del(&page->page_list); | |
253 | kfree(page); | |
254 | } | |
255 | ||
256 | /** | |
257 | * dma_pool_destroy - destroys a pool of dma memory blocks. | |
258 | * @pool: dma pool that will be destroyed | |
259 | * Context: !in_interrupt() | |
260 | * | |
261 | * Caller guarantees that no more memory from the pool is in use, | |
262 | * and that nothing will try to use the pool after this call. | |
263 | */ | |
264 | void dma_pool_destroy(struct dma_pool *pool) | |
265 | { | |
266 | mutex_lock(&pools_lock); | |
267 | list_del(&pool->pools); | |
268 | if (pool->dev && list_empty(&pool->dev->dma_pools)) | |
269 | device_remove_file(pool->dev, &dev_attr_pools); | |
270 | mutex_unlock(&pools_lock); | |
271 | ||
272 | while (!list_empty(&pool->page_list)) { | |
273 | struct dma_page *page; | |
274 | page = list_entry(pool->page_list.next, | |
275 | struct dma_page, page_list); | |
276 | if (is_page_busy(page)) { | |
277 | if (pool->dev) | |
278 | dev_err(pool->dev, | |
279 | "dma_pool_destroy %s, %p busy\n", | |
280 | pool->name, page->vaddr); | |
281 | else | |
282 | printk(KERN_ERR | |
283 | "dma_pool_destroy %s, %p busy\n", | |
284 | pool->name, page->vaddr); | |
285 | /* leak the still-in-use consistent memory */ | |
286 | list_del(&page->page_list); | |
287 | kfree(page); | |
288 | } else | |
289 | pool_free_page(pool, page); | |
290 | } | |
291 | ||
292 | kfree(pool); | |
293 | } | |
294 | EXPORT_SYMBOL(dma_pool_destroy); | |
295 | ||
296 | /** | |
297 | * dma_pool_alloc - get a block of consistent memory | |
298 | * @pool: dma pool that will produce the block | |
299 | * @mem_flags: GFP_* bitmask | |
300 | * @handle: pointer to dma address of block | |
301 | * | |
302 | * This returns the kernel virtual address of a currently unused block, | |
303 | * and reports its dma address through the handle. | |
304 | * If such a memory block can't be allocated, %NULL is returned. | |
305 | */ | |
306 | void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, | |
307 | dma_addr_t *handle) | |
308 | { | |
309 | unsigned long flags; | |
310 | struct dma_page *page; | |
311 | size_t offset; | |
312 | void *retval; | |
313 | ||
314 | might_sleep_if(mem_flags & __GFP_WAIT); | |
315 | ||
316 | spin_lock_irqsave(&pool->lock, flags); | |
317 | restart: | |
318 | list_for_each_entry(page, &pool->page_list, page_list) { | |
319 | if (page->offset < pool->allocation) | |
320 | goto ready; | |
321 | } | |
322 | page = pool_alloc_page(pool, GFP_ATOMIC); | |
323 | if (!page) { | |
324 | if (mem_flags & __GFP_WAIT) { | |
325 | DECLARE_WAITQUEUE(wait, current); | |
326 | ||
327 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
328 | __add_wait_queue(&pool->waitq, &wait); | |
329 | spin_unlock_irqrestore(&pool->lock, flags); | |
330 | ||
331 | schedule_timeout(POOL_TIMEOUT_JIFFIES); | |
332 | ||
333 | spin_lock_irqsave(&pool->lock, flags); | |
334 | __remove_wait_queue(&pool->waitq, &wait); | |
335 | goto restart; | |
336 | } | |
337 | retval = NULL; | |
338 | goto done; | |
339 | } | |
340 | ||
341 | ready: | |
342 | page->in_use++; | |
343 | offset = page->offset; | |
344 | page->offset = *(int *)(page->vaddr + offset); | |
345 | retval = offset + page->vaddr; | |
346 | *handle = offset + page->dma; | |
347 | #ifdef DMAPOOL_DEBUG | |
348 | memset(retval, POOL_POISON_ALLOCATED, pool->size); | |
349 | #endif | |
350 | done: | |
351 | spin_unlock_irqrestore(&pool->lock, flags); | |
352 | return retval; | |
353 | } | |
354 | EXPORT_SYMBOL(dma_pool_alloc); | |
355 | ||
356 | static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) | |
357 | { | |
358 | struct dma_page *page; | |
359 | ||
360 | list_for_each_entry(page, &pool->page_list, page_list) { | |
361 | if (dma < page->dma) | |
362 | continue; | |
363 | if (dma < (page->dma + pool->allocation)) | |
364 | return page; | |
365 | } | |
366 | return NULL; | |
367 | } | |
368 | ||
369 | /** | |
370 | * dma_pool_free - put block back into dma pool | |
371 | * @pool: the dma pool holding the block | |
372 | * @vaddr: virtual address of block | |
373 | * @dma: dma address of block | |
374 | * | |
375 | * Caller promises neither device nor driver will again touch this block | |
376 | * unless it is first re-allocated. | |
377 | */ | |
378 | void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) | |
379 | { | |
380 | struct dma_page *page; | |
381 | unsigned long flags; | |
382 | unsigned int offset; | |
383 | ||
384 | spin_lock_irqsave(&pool->lock, flags); | |
385 | page = pool_find_page(pool, dma); | |
386 | if (!page) { | |
387 | spin_unlock_irqrestore(&pool->lock, flags); | |
388 | if (pool->dev) | |
389 | dev_err(pool->dev, | |
390 | "dma_pool_free %s, %p/%lx (bad dma)\n", | |
391 | pool->name, vaddr, (unsigned long)dma); | |
392 | else | |
393 | printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n", | |
394 | pool->name, vaddr, (unsigned long)dma); | |
395 | return; | |
396 | } | |
397 | ||
398 | offset = vaddr - page->vaddr; | |
399 | #ifdef DMAPOOL_DEBUG | |
400 | if ((dma - page->dma) != offset) { | |
401 | spin_unlock_irqrestore(&pool->lock, flags); | |
402 | if (pool->dev) | |
403 | dev_err(pool->dev, | |
404 | "dma_pool_free %s, %p (bad vaddr)/%Lx\n", | |
405 | pool->name, vaddr, (unsigned long long)dma); | |
406 | else | |
407 | printk(KERN_ERR | |
408 | "dma_pool_free %s, %p (bad vaddr)/%Lx\n", | |
409 | pool->name, vaddr, (unsigned long long)dma); | |
410 | return; | |
411 | } | |
412 | { | |
413 | unsigned int chain = page->offset; | |
414 | while (chain < pool->allocation) { | |
415 | if (chain != offset) { | |
416 | chain = *(int *)(page->vaddr + chain); | |
417 | continue; | |
418 | } | |
419 | spin_unlock_irqrestore(&pool->lock, flags); | |
420 | if (pool->dev) | |
421 | dev_err(pool->dev, "dma_pool_free %s, dma %Lx " | |
422 | "already free\n", pool->name, | |
423 | (unsigned long long)dma); | |
424 | else | |
425 | printk(KERN_ERR "dma_pool_free %s, dma %Lx " | |
426 | "already free\n", pool->name, | |
427 | (unsigned long long)dma); | |
428 | return; | |
429 | } | |
430 | } | |
431 | memset(vaddr, POOL_POISON_FREED, pool->size); | |
432 | #endif | |
433 | ||
434 | page->in_use--; | |
435 | *(int *)vaddr = page->offset; | |
436 | page->offset = offset; | |
437 | if (waitqueue_active(&pool->waitq)) | |
438 | wake_up_locked(&pool->waitq); | |
439 | /* | |
440 | * Resist a temptation to do | |
441 | * if (!is_page_busy(page)) pool_free_page(pool, page); | |
442 | * Better have a few empty pages hang around. | |
443 | */ | |
444 | spin_unlock_irqrestore(&pool->lock, flags); | |
445 | } | |
446 | EXPORT_SYMBOL(dma_pool_free); | |
447 | ||
448 | /* | |
449 | * Managed DMA pool | |
450 | */ | |
451 | static void dmam_pool_release(struct device *dev, void *res) | |
452 | { | |
453 | struct dma_pool *pool = *(struct dma_pool **)res; | |
454 | ||
455 | dma_pool_destroy(pool); | |
456 | } | |
457 | ||
458 | static int dmam_pool_match(struct device *dev, void *res, void *match_data) | |
459 | { | |
460 | return *(struct dma_pool **)res == match_data; | |
461 | } | |
462 | ||
463 | /** | |
464 | * dmam_pool_create - Managed dma_pool_create() | |
465 | * @name: name of pool, for diagnostics | |
466 | * @dev: device that will be doing the DMA | |
467 | * @size: size of the blocks in this pool. | |
468 | * @align: alignment requirement for blocks; must be a power of two | |
469 | * @allocation: returned blocks won't cross this boundary (or zero) | |
470 | * | |
471 | * Managed dma_pool_create(). DMA pool created with this function is | |
472 | * automatically destroyed on driver detach. | |
473 | */ | |
474 | struct dma_pool *dmam_pool_create(const char *name, struct device *dev, | |
475 | size_t size, size_t align, size_t allocation) | |
476 | { | |
477 | struct dma_pool **ptr, *pool; | |
478 | ||
479 | ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL); | |
480 | if (!ptr) | |
481 | return NULL; | |
482 | ||
483 | pool = *ptr = dma_pool_create(name, dev, size, align, allocation); | |
484 | if (pool) | |
485 | devres_add(dev, ptr); | |
486 | else | |
487 | devres_free(ptr); | |
488 | ||
489 | return pool; | |
490 | } | |
491 | EXPORT_SYMBOL(dmam_pool_create); | |
492 | ||
493 | /** | |
494 | * dmam_pool_destroy - Managed dma_pool_destroy() | |
495 | * @pool: dma pool that will be destroyed | |
496 | * | |
497 | * Managed dma_pool_destroy(). | |
498 | */ | |
499 | void dmam_pool_destroy(struct dma_pool *pool) | |
500 | { | |
501 | struct device *dev = pool->dev; | |
502 | ||
503 | WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool)); | |
504 | dma_pool_destroy(pool); | |
505 | } | |
506 | EXPORT_SYMBOL(dmam_pool_destroy); |