1 /*
2 NOTE:
3
4 this code was lifted straight out of drivers/pci/pci.c;
5 when compiling for the Intel StrongARM SA-1110/SA-1111 the
6 usb-ohci.c driver needs these routines even when the architecture
7 has no pci bus...
8 */
9
10 #include <linux/config.h>
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/pci.h>
15 #include <linux/string.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
19 #include <linux/bitops.h>
20
21 #include <asm/page.h>
22
23 /*
24 * Pool allocator ... wraps the pci_alloc_consistent page allocator, so
25 * small blocks are easily used by drivers for bus mastering controllers.
26 * This should probably be sharing the guts of the slab allocator.
27 */
28
29 struct pci_pool { /* the pool */
30 struct list_head page_list;
31 spinlock_t lock;
32 size_t blocks_per_page;
33 size_t size;
34 struct pci_dev *dev;
35 size_t allocation;
36 char name [32];
37 wait_queue_head_t waitq;
38 };
39
40 struct pci_page { /* cacheable header for 'allocation' bytes */
41 struct list_head page_list;
42 void *vaddr;
43 dma_addr_t dma;
44 unsigned long bitmap [0];
45 };
46
47 #define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
48 #define POOL_POISON_BYTE 0xa7
49
50 // #define CONFIG_PCIPOOL_DEBUG
51
slot_name(const struct pci_pool * pool)52 static inline const char *slot_name(const struct pci_pool *pool)
53 {
54 const struct pci_dev *pdev = pool->dev;
55
56 if (pdev == 0)
57 return "[0]";
58
59 else if (dev_is_sa1111(pdev))
60 return "[SA-1111]";
61 else
62 return pdev->slot_name;
63 }
64
65
66 /**
67 * pci_pool_create - Creates a pool of pci consistent memory blocks, for dma.
68 * @name: name of pool, for diagnostics
69 * @pdev: pci device that will be doing the DMA
70 * @size: size of the blocks in this pool.
71 * @align: alignment requirement for blocks; must be a power of two
72 * @allocation: returned blocks won't cross this boundary (or zero)
73 * @mem_flags: SLAB_* flags.
74 *
75 * Returns a pci allocation pool with the requested characteristics, or
76 * null if one can't be created. Given one of these pools, pci_pool_alloc()
77 * may be used to allocate memory. Such memory will all have "consistent"
78 * DMA mappings, accessible by the device and its driver without using
79 * cache flushing primitives. The actual size of blocks allocated may be
80 * larger than requested because of alignment.
81 *
82 * If allocation is nonzero, objects returned from pci_pool_alloc() won't
83 * cross that size boundary. This is useful for devices which have
84 * addressing restrictions on individual DMA transfers, such as not crossing
85 * boundaries of 4KBytes.
86 */
87 struct pci_pool *
pci_pool_create(const char * name,struct pci_dev * pdev,size_t size,size_t align,size_t allocation,int mem_flags)88 pci_pool_create (const char *name, struct pci_dev *pdev,
89 size_t size, size_t align, size_t allocation, int mem_flags)
90 {
91 struct pci_pool *retval;
92
93 if (align == 0)
94 align = 1;
95 if (size == 0)
96 return 0;
97 else if (size < align)
98 size = align;
99 else if ((size % align) != 0) {
100 size += align + 1;
101 size &= ~(align - 1);
102 }
103
104 if (allocation == 0) {
105 if (PAGE_SIZE < size)
106 allocation = size;
107 else
108 allocation = PAGE_SIZE;
109 // FIXME: round up for less fragmentation
110 } else if (allocation < size)
111 return 0;
112
113 if (!(retval = kmalloc (sizeof *retval, mem_flags)))
114 return retval;
115
116 strncpy (retval->name, name, sizeof retval->name);
117 retval->name [sizeof retval->name - 1] = 0;
118
119 retval->dev = pdev;
120 INIT_LIST_HEAD (&retval->page_list);
121 spin_lock_init (&retval->lock);
122 retval->size = size;
123 retval->allocation = allocation;
124 retval->blocks_per_page = allocation / size;
125 init_waitqueue_head (&retval->waitq);
126
127 #ifdef CONFIG_PCIPOOL_DEBUG
128 printk (KERN_DEBUG "pcipool create %s/%s size %d, %d/page (%d alloc)\n",
129 slot_name(retval), retval->name, size,
130 retval->blocks_per_page, allocation);
131 #endif
132
133 return retval;
134 }
135
136
137 static struct pci_page *
pool_alloc_page(struct pci_pool * pool,int mem_flags)138 pool_alloc_page (struct pci_pool *pool, int mem_flags)
139 {
140 struct pci_page *page;
141 int mapsize;
142
143 mapsize = pool->blocks_per_page;
144 mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
145 mapsize *= sizeof (long);
146
147 page = (struct pci_page *) kmalloc (mapsize + sizeof *page, mem_flags);
148 if (!page)
149 return 0;
150 page->vaddr = pci_alloc_consistent (pool->dev,
151 pool->allocation,
152 &page->dma);
153 if (page->vaddr) {
154 memset (page->bitmap, 0xff, mapsize); // bit set == free
155 #ifdef CONFIG_DEBUG_SLAB
156 memset (page->vaddr, POOL_POISON_BYTE, pool->allocation);
157 #endif
158 list_add (&page->page_list, &pool->page_list);
159 } else {
160 kfree (page);
161 page = 0;
162 }
163 return page;
164 }
165
166
167 static inline int
is_page_busy(int blocks,unsigned long * bitmap)168 is_page_busy (int blocks, unsigned long *bitmap)
169 {
170 while (blocks > 0) {
171 if (*bitmap++ != ~0UL)
172 return 1;
173 blocks -= BITS_PER_LONG;
174 }
175 return 0;
176 }
177
178 static void
pool_free_page(struct pci_pool * pool,struct pci_page * page)179 pool_free_page (struct pci_pool *pool, struct pci_page *page)
180 {
181 dma_addr_t dma = page->dma;
182
183 #ifdef CONFIG_DEBUG_SLAB
184 memset (page->vaddr, POOL_POISON_BYTE, pool->allocation);
185 #endif
186 pci_free_consistent (pool->dev, pool->allocation, page->vaddr, dma);
187 list_del (&page->page_list);
188 kfree (page);
189 }
190
191
192 /**
193 * pci_pool_destroy - destroys a pool of pci memory blocks.
194 * @pool: pci pool that will be destroyed
195 *
196 * Caller guarantees that no more memory from the pool is in use,
197 * and that nothing will try to use the pool after this call.
198 */
199 void
pci_pool_destroy(struct pci_pool * pool)200 pci_pool_destroy (struct pci_pool *pool)
201 {
202 unsigned long flags;
203
204 #ifdef CONFIG_PCIPOOL_DEBUG
205 printk (KERN_DEBUG "pcipool destroy %s/%s\n",
206 slot_name(pool), pool->name);
207 #endif
208
209 spin_lock_irqsave (&pool->lock, flags);
210 while (!list_empty (&pool->page_list)) {
211 struct pci_page *page;
212 page = list_entry (pool->page_list.next,
213 struct pci_page, page_list);
214 if (is_page_busy (pool->blocks_per_page, page->bitmap)) {
215 printk (KERN_ERR "pci_pool_destroy %s/%s, %p busy\n",
216 slot_name(pool), pool->name, page->vaddr);
217 /* leak the still-in-use consistent memory */
218 list_del (&page->page_list);
219 kfree (page);
220 } else
221 pool_free_page (pool, page);
222 }
223 spin_unlock_irqrestore (&pool->lock, flags);
224 kfree (pool);
225 }
226
227
228 /**
229 * pci_pool_alloc - get a block of consistent memory
230 * @pool: pci pool that will produce the block
231 * @mem_flags: SLAB_KERNEL or SLAB_ATOMIC
232 * @handle: pointer to dma address of block
233 *
234 * This returns the kernel virtual address of a currently unused block,
235 * and reports its dma address through the handle.
236 * If such a memory block can't be allocated, null is returned.
237 */
238 void *
pci_pool_alloc(struct pci_pool * pool,int mem_flags,dma_addr_t * handle)239 pci_pool_alloc (struct pci_pool *pool, int mem_flags, dma_addr_t *handle)
240 {
241 unsigned long flags;
242 struct list_head *entry;
243 struct pci_page *page;
244 int map, block;
245 size_t offset;
246 void *retval;
247
248 restart:
249 spin_lock_irqsave (&pool->lock, flags);
250 list_for_each (entry, &pool->page_list) {
251 int i;
252 page = list_entry (entry, struct pci_page, page_list);
253 /* only cachable accesses here ... */
254 for (map = 0, i = 0;
255 i < pool->blocks_per_page;
256 i += BITS_PER_LONG, map++) {
257 if (page->bitmap [map] == 0)
258 continue;
259 block = ffz (~ page->bitmap [map]);
260 if ((i + block) < pool->blocks_per_page) {
261 clear_bit (block, &page->bitmap [map]);
262 offset = (BITS_PER_LONG * map) + block;
263 offset *= pool->size;
264 goto ready;
265 }
266 }
267 }
268 if (!(page = pool_alloc_page (pool, mem_flags))) {
269 if (mem_flags == SLAB_KERNEL) {
270 DECLARE_WAITQUEUE (wait, current);
271
272 current->state = TASK_INTERRUPTIBLE;
273 add_wait_queue (&pool->waitq, &wait);
274 spin_unlock_irqrestore (&pool->lock, flags);
275
276 schedule_timeout (POOL_TIMEOUT_JIFFIES);
277
278 current->state = TASK_RUNNING;
279 remove_wait_queue (&pool->waitq, &wait);
280 goto restart;
281 }
282 retval = 0;
283 goto done;
284 }
285
286 clear_bit (0, &page->bitmap [0]);
287 offset = 0;
288 ready:
289 retval = offset + page->vaddr;
290 *handle = offset + page->dma;
291 done:
292 spin_unlock_irqrestore (&pool->lock, flags);
293 return retval;
294 }
295
296
297 static struct pci_page *
pool_find_page(struct pci_pool * pool,dma_addr_t dma)298 pool_find_page (struct pci_pool *pool, dma_addr_t dma)
299 {
300 unsigned long flags;
301 struct list_head *entry;
302 struct pci_page *page;
303
304 spin_lock_irqsave (&pool->lock, flags);
305 list_for_each (entry, &pool->page_list) {
306 page = list_entry (entry, struct pci_page, page_list);
307 if (dma < page->dma)
308 continue;
309 if (dma < (page->dma + pool->allocation))
310 goto done;
311 }
312 page = 0;
313 done:
314 spin_unlock_irqrestore (&pool->lock, flags);
315 return page;
316 }
317
318
319 /**
320 * pci_pool_free - put block back into pci pool
321 * @pool: the pci pool holding the block
322 * @vaddr: virtual address of block
323 * @dma: dma address of block
324 *
325 * Caller promises neither device nor driver will again touch this block
326 * unless it is first re-allocated.
327 */
328 void
pci_pool_free(struct pci_pool * pool,void * vaddr,dma_addr_t dma)329 pci_pool_free (struct pci_pool *pool, void *vaddr, dma_addr_t dma)
330 {
331 struct pci_page *page;
332 unsigned long flags;
333 int map, block;
334
335 if ((page = pool_find_page (pool, dma)) == 0) {
336 printk (KERN_ERR "pci_pool_free %s/%s, %p/%lx (bad dma)\n",
337 pool->dev ? pool->dev->slot_name : NULL,
338 pool->name, vaddr, (unsigned long) dma);
339 return;
340 }
341
342 block = dma - page->dma;
343 block /= pool->size;
344 map = block / BITS_PER_LONG;
345 block %= BITS_PER_LONG;
346
347 #ifdef CONFIG_DEBUG_SLAB
348 if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
349 printk (KERN_ERR "pci_pool_free %s/%s, %p (bad vaddr)/%lx\n",
350 pool->dev ? pool->dev->slot_name : NULL,
351 pool->name, vaddr, (unsigned long) dma);
352 return;
353 }
354 if (page->bitmap [map] & (1UL << block)) {
355 printk (KERN_ERR "pci_pool_free %s/%s, dma %x already free\n",
356 pool->dev ? pool->dev->slot_name : NULL,
357 pool->name, dma);
358 return;
359 }
360 memset (vaddr, POOL_POISON_BYTE, pool->size);
361 #endif
362
363 spin_lock_irqsave (&pool->lock, flags);
364 set_bit (block, &page->bitmap [map]);
365 if (waitqueue_active (&pool->waitq))
366 wake_up (&pool->waitq);
367 /*
368 * Resist a temptation to do
369 * if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
370 * it is not interrupt safe. Better have empty pages hang around.
371 */
372 spin_unlock_irqrestore (&pool->lock, flags);
373 }
374
375
376 EXPORT_SYMBOL (pci_pool_create);
377 EXPORT_SYMBOL (pci_pool_destroy);
378 EXPORT_SYMBOL (pci_pool_alloc);
379 EXPORT_SYMBOL (pci_pool_free);
380
381 /* **************************************** */
382
pcipool_init(void)383 static int __init pcipool_init(void)
384 {
385 MOD_INC_USE_COUNT; /* never unload */
386
387 return 0;
388 }
389 module_init(pcipool_init);
390
391 MODULE_LICENSE("GPL");
392