xref: /freebsd/sys/dev/mthca/mthca_memfree.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*
2  * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
3  * Copyright (c) 2005 Cisco Systems.  All rights reserved.
4  * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
5  *
6  * This software is available to you under a choice of one of two
7  * licenses.  You may choose to be licensed under the terms of the GNU
8  * General Public License (GPL) Version 2, available from the file
9  * COPYING in the main directory of this source tree, or the
10  * OpenIB.org BSD license below:
11  *
12  *     Redistribution and use in source and binary forms, with or
13  *     without modification, are permitted provided that the following
14  *     conditions are met:
15  *
16  *      - Redistributions of source code must retain the above
17  *        copyright notice, this list of conditions and the following
18  *        disclaimer.
19  *
20  *      - Redistributions in binary form must reproduce the above
21  *        copyright notice, this list of conditions and the following
22  *        disclaimer in the documentation and/or other materials
23  *        provided with the distribution.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
29  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
30  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
31  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32  * SOFTWARE.
33  */
34 
35 #include <linux/mm.h>
36 #include <linux/scatterlist.h>
37 #include <linux/sched.h>
38 #include <linux/slab.h>
39 #include <linux/page.h>
40 
41 #include "mthca_memfree.h"
42 #include "mthca_dev.h"
43 #include "mthca_cmd.h"
44 
45 /*
46  * We allocate in as big chunks as we can, up to a maximum of 256 KB
47  * per chunk.
48  */
49 enum {
50 	MTHCA_ICM_ALLOC_SIZE   = 1 << 18,
51 	MTHCA_TABLE_CHUNK_SIZE = 1 << 18
52 };
53 
54 struct mthca_user_db_table {
55 	struct mutex mutex;
56 	struct {
57 		u64                uvirt;
58 		struct scatterlist mem;
59 		int                refcount;
60 	}                page[0];
61 };
62 
63 static void mthca_free_icm_pages(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
64 {
65 	int i;
66 
67 	if (chunk->nsg > 0)
68 		pci_unmap_sg(dev->pdev, chunk->mem, chunk->npages,
69 			     PCI_DMA_BIDIRECTIONAL);
70 
71 	for (i = 0; i < chunk->npages; ++i)
72 		__free_pages(sg_page(&chunk->mem[i]),
73 			     get_order(chunk->mem[i].length));
74 }
75 
76 static void mthca_free_icm_coherent(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
77 {
78 	int i;
79 
80 	for (i = 0; i < chunk->npages; ++i) {
81 		dma_free_coherent(&dev->pdev->dev, chunk->mem[i].length,
82 				  lowmem_page_address(sg_page(&chunk->mem[i])),
83 				  sg_dma_address(&chunk->mem[i]));
84 	}
85 }
86 
87 void mthca_free_icm(struct mthca_dev *dev, struct mthca_icm *icm, int coherent)
88 {
89 	struct mthca_icm_chunk *chunk, *tmp;
90 
91 	if (!icm)
92 		return;
93 
94 	list_for_each_entry_safe(chunk, tmp, &icm->chunk_list, list) {
95 		if (coherent)
96 			mthca_free_icm_coherent(dev, chunk);
97 		else
98 			mthca_free_icm_pages(dev, chunk);
99 
100 		kfree(chunk);
101 	}
102 
103 	kfree(icm);
104 }
105 
106 static int mthca_alloc_icm_pages(struct scatterlist *mem, int order, gfp_t gfp_mask)
107 {
108 	struct page *page;
109 
110 	/*
111 	 * Use __GFP_ZERO because buggy firmware assumes ICM pages are
112 	 * cleared, and subtle failures are seen if they aren't.
113 	 */
114 	page = alloc_pages(gfp_mask | __GFP_ZERO, order);
115 	if (!page)
116 		return -ENOMEM;
117 
118 	sg_set_page(mem, page, PAGE_SIZE << order, 0);
119 	return 0;
120 }
121 
122 static int mthca_alloc_icm_coherent(struct device *dev, struct scatterlist *mem,
123 				    int order, gfp_t gfp_mask)
124 {
125 	void *buf = dma_alloc_coherent(dev, PAGE_SIZE << order, &sg_dma_address(mem),
126 				       gfp_mask);
127 	if (!buf)
128 		return -ENOMEM;
129 
130 	sg_set_buf(mem, buf, PAGE_SIZE << order);
131 	BUG_ON(mem->offset);
132 	sg_dma_len(mem) = PAGE_SIZE << order;
133 	return 0;
134 }
135 
136 struct mthca_icm *mthca_alloc_icm(struct mthca_dev *dev, int npages,
137 				  gfp_t gfp_mask, int coherent)
138 {
139 	struct mthca_icm *icm;
140 	struct mthca_icm_chunk *chunk = NULL;
141 	int cur_order;
142 	int ret;
143 
144 	/* We use sg_set_buf for coherent allocs, which assumes low memory */
145 	BUG_ON(coherent && (gfp_mask & __GFP_HIGHMEM));
146 
147 	icm = kmalloc(sizeof *icm, gfp_mask & ~(__GFP_HIGHMEM | __GFP_NOWARN));
148 	if (!icm)
149 		return icm;
150 
151 	icm->refcount = 0;
152 	INIT_LIST_HEAD(&icm->chunk_list);
153 
154 	cur_order = get_order(MTHCA_ICM_ALLOC_SIZE);
155 
156 	while (npages > 0) {
157 		if (!chunk) {
158 			chunk = kmalloc(sizeof *chunk,
159 					gfp_mask & ~(__GFP_HIGHMEM | __GFP_NOWARN));
160 			if (!chunk)
161 				goto fail;
162 
163 			sg_init_table(chunk->mem, MTHCA_ICM_CHUNK_LEN);
164 			chunk->npages = 0;
165 			chunk->nsg    = 0;
166 			list_add_tail(&chunk->list, &icm->chunk_list);
167 		}
168 
169 		while (1 << cur_order > npages)
170 			--cur_order;
171 
172 		if (coherent)
173 			ret = mthca_alloc_icm_coherent(&dev->pdev->dev,
174 						       &chunk->mem[chunk->npages],
175 						       cur_order, gfp_mask);
176 		else
177 			ret = mthca_alloc_icm_pages(&chunk->mem[chunk->npages],
178 						    cur_order, gfp_mask);
179 
180 		if (!ret) {
181 			++chunk->npages;
182 
183 			if (coherent)
184 				++chunk->nsg;
185 			else if (chunk->npages == MTHCA_ICM_CHUNK_LEN) {
186 				chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
187 							chunk->npages,
188 							PCI_DMA_BIDIRECTIONAL);
189 
190 				if (chunk->nsg <= 0)
191 					goto fail;
192 			}
193 
194 			if (chunk->npages == MTHCA_ICM_CHUNK_LEN)
195 				chunk = NULL;
196 
197 			npages -= 1 << cur_order;
198 		} else {
199 			--cur_order;
200 			if (cur_order < 0)
201 				goto fail;
202 		}
203 	}
204 
205 	if (!coherent && chunk) {
206 		chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
207 					chunk->npages,
208 					PCI_DMA_BIDIRECTIONAL);
209 
210 		if (chunk->nsg <= 0)
211 			goto fail;
212 	}
213 
214 	return icm;
215 
216 fail:
217 	mthca_free_icm(dev, icm, coherent);
218 	return NULL;
219 }
220 
221 int mthca_table_get(struct mthca_dev *dev, struct mthca_icm_table *table, int obj)
222 {
223 	int i = (obj & (table->num_obj - 1)) * table->obj_size / MTHCA_TABLE_CHUNK_SIZE;
224 	int ret = 0;
225 
226 	mutex_lock(&table->mutex);
227 
228 	if (table->icm[i]) {
229 		++table->icm[i]->refcount;
230 		goto out;
231 	}
232 
233 	table->icm[i] = mthca_alloc_icm(dev, MTHCA_TABLE_CHUNK_SIZE >> PAGE_SHIFT,
234 					(table->lowmem ? GFP_KERNEL : GFP_HIGHUSER) |
235 					__GFP_NOWARN, table->coherent);
236 	if (!table->icm[i]) {
237 		ret = -ENOMEM;
238 		goto out;
239 	}
240 
241 	if (mthca_MAP_ICM(dev, table->icm[i],
242 			  table->virt + i * MTHCA_TABLE_CHUNK_SIZE)) {
243 		mthca_free_icm(dev, table->icm[i], table->coherent);
244 		table->icm[i] = NULL;
245 		ret = -ENOMEM;
246 		goto out;
247 	}
248 
249 	++table->icm[i]->refcount;
250 
251 out:
252 	mutex_unlock(&table->mutex);
253 	return ret;
254 }
255 
256 void mthca_table_put(struct mthca_dev *dev, struct mthca_icm_table *table, int obj)
257 {
258 	int i;
259 
260 	if (!mthca_is_memfree(dev))
261 		return;
262 
263 	i = (obj & (table->num_obj - 1)) * table->obj_size / MTHCA_TABLE_CHUNK_SIZE;
264 
265 	mutex_lock(&table->mutex);
266 
267 	if (--table->icm[i]->refcount == 0) {
268 		mthca_UNMAP_ICM(dev, table->virt + i * MTHCA_TABLE_CHUNK_SIZE,
269 				MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
270 		mthca_free_icm(dev, table->icm[i], table->coherent);
271 		table->icm[i] = NULL;
272 	}
273 
274 	mutex_unlock(&table->mutex);
275 }
276 
277 void *mthca_table_find(struct mthca_icm_table *table, int obj, dma_addr_t *dma_handle)
278 {
279 	int idx, offset, dma_offset, i;
280 	struct mthca_icm_chunk *chunk;
281 	struct mthca_icm *icm;
282 	struct page *page = NULL;
283 
284 	if (!table->lowmem)
285 		return NULL;
286 
287 	mutex_lock(&table->mutex);
288 
289 	idx = (obj & (table->num_obj - 1)) * table->obj_size;
290 	icm = table->icm[idx / MTHCA_TABLE_CHUNK_SIZE];
291 	dma_offset = offset = idx % MTHCA_TABLE_CHUNK_SIZE;
292 
293 	if (!icm)
294 		goto out;
295 
296 	list_for_each_entry(chunk, &icm->chunk_list, list) {
297 		for (i = 0; i < chunk->npages; ++i) {
298 			if (dma_handle && dma_offset >= 0) {
299 				if (sg_dma_len(&chunk->mem[i]) > dma_offset)
300 					*dma_handle = sg_dma_address(&chunk->mem[i]) +
301 						dma_offset;
302 				dma_offset -= sg_dma_len(&chunk->mem[i]);
303 			}
304 			/* DMA mapping can merge pages but not split them,
305 			 * so if we found the page, dma_handle has already
306 			 * been assigned to. */
307 			if (chunk->mem[i].length > offset) {
308 				page = sg_page(&chunk->mem[i]);
309 				goto out;
310 			}
311 			offset -= chunk->mem[i].length;
312 		}
313 	}
314 
315 out:
316 	mutex_unlock(&table->mutex);
317 	return page ? lowmem_page_address(page) + offset : NULL;
318 }
319 
320 int mthca_table_get_range(struct mthca_dev *dev, struct mthca_icm_table *table,
321 			  int start, int end)
322 {
323 	int inc = MTHCA_TABLE_CHUNK_SIZE / table->obj_size;
324 	int i, err;
325 
326 	for (i = start; i <= end; i += inc) {
327 		err = mthca_table_get(dev, table, i);
328 		if (err)
329 			goto fail;
330 	}
331 
332 	return 0;
333 
334 fail:
335 	while (i > start) {
336 		i -= inc;
337 		mthca_table_put(dev, table, i);
338 	}
339 
340 	return err;
341 }
342 
343 void mthca_table_put_range(struct mthca_dev *dev, struct mthca_icm_table *table,
344 			   int start, int end)
345 {
346 	int i;
347 
348 	if (!mthca_is_memfree(dev))
349 		return;
350 
351 	for (i = start; i <= end; i += MTHCA_TABLE_CHUNK_SIZE / table->obj_size)
352 		mthca_table_put(dev, table, i);
353 }
354 
355 struct mthca_icm_table *mthca_alloc_icm_table(struct mthca_dev *dev,
356 					      u64 virt, int obj_size,
357 					      int nobj, int reserved,
358 					      int use_lowmem, int use_coherent)
359 {
360 	struct mthca_icm_table *table;
361 	int obj_per_chunk;
362 	int num_icm;
363 	unsigned chunk_size;
364 	int i;
365 
366 	obj_per_chunk = MTHCA_TABLE_CHUNK_SIZE / obj_size;
367 	num_icm = DIV_ROUND_UP(nobj, obj_per_chunk);
368 
369 	table = kmalloc(sizeof *table + num_icm * sizeof *table->icm, GFP_KERNEL);
370 	if (!table)
371 		return NULL;
372 
373 	table->virt     = virt;
374 	table->num_icm  = num_icm;
375 	table->num_obj  = nobj;
376 	table->obj_size = obj_size;
377 	table->lowmem   = use_lowmem;
378 	table->coherent = use_coherent;
379 	mutex_init(&table->mutex);
380 
381 	for (i = 0; i < num_icm; ++i)
382 		table->icm[i] = NULL;
383 
384 	for (i = 0; i * MTHCA_TABLE_CHUNK_SIZE < reserved * obj_size; ++i) {
385 		chunk_size = MTHCA_TABLE_CHUNK_SIZE;
386 		if ((i + 1) * MTHCA_TABLE_CHUNK_SIZE > nobj * obj_size)
387 			chunk_size = nobj * obj_size - i * MTHCA_TABLE_CHUNK_SIZE;
388 
389 		table->icm[i] = mthca_alloc_icm(dev, chunk_size >> PAGE_SHIFT,
390 						(use_lowmem ? GFP_KERNEL : GFP_HIGHUSER) |
391 						__GFP_NOWARN, use_coherent);
392 		if (!table->icm[i])
393 			goto err;
394 		if (mthca_MAP_ICM(dev, table->icm[i],
395 				  virt + i * MTHCA_TABLE_CHUNK_SIZE)) {
396 			mthca_free_icm(dev, table->icm[i], table->coherent);
397 			table->icm[i] = NULL;
398 			goto err;
399 		}
400 
401 		/*
402 		 * Add a reference to this ICM chunk so that it never
403 		 * gets freed (since it contains reserved firmware objects).
404 		 */
405 		++table->icm[i]->refcount;
406 	}
407 
408 	return table;
409 
410 err:
411 	for (i = 0; i < num_icm; ++i)
412 		if (table->icm[i]) {
413 			mthca_UNMAP_ICM(dev, virt + i * MTHCA_TABLE_CHUNK_SIZE,
414 					MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
415 			mthca_free_icm(dev, table->icm[i], table->coherent);
416 		}
417 
418 	kfree(table);
419 
420 	return NULL;
421 }
422 
423 void mthca_free_icm_table(struct mthca_dev *dev, struct mthca_icm_table *table)
424 {
425 	int i;
426 
427 	for (i = 0; i < table->num_icm; ++i)
428 		if (table->icm[i]) {
429 			mthca_UNMAP_ICM(dev,
430 					table->virt + i * MTHCA_TABLE_CHUNK_SIZE,
431 					MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
432 			mthca_free_icm(dev, table->icm[i], table->coherent);
433 		}
434 
435 	kfree(table);
436 }
437 
438 static u64 mthca_uarc_virt(struct mthca_dev *dev, struct mthca_uar *uar, int page)
439 {
440 	return dev->uar_table.uarc_base +
441 		uar->index * dev->uar_table.uarc_size +
442 		page * MTHCA_ICM_PAGE_SIZE;
443 }
444 
445 int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
446 		      struct mthca_user_db_table *db_tab, int index, u64 uaddr)
447 {
448 	struct page *pages[1];
449 	int ret = 0;
450 	int i;
451 
452 	if (!mthca_is_memfree(dev))
453 		return 0;
454 
455 	if (index < 0 || index > dev->uar_table.uarc_size / 8)
456 		return -EINVAL;
457 
458 	mutex_lock(&db_tab->mutex);
459 
460 	i = index / MTHCA_DB_REC_PER_PAGE;
461 
462 	if ((db_tab->page[i].refcount >= MTHCA_DB_REC_PER_PAGE)       ||
463 	    (db_tab->page[i].uvirt && db_tab->page[i].uvirt != uaddr) ||
464 	    (uaddr & 4095)) {
465 		ret = -EINVAL;
466 		goto out;
467 	}
468 
469 	if (db_tab->page[i].refcount) {
470 		++db_tab->page[i].refcount;
471 		goto out;
472 	}
473 
474 	ret = get_user_pages(uaddr & PAGE_MASK, 1, FOLL_WRITE, pages, NULL);
475 	if (ret < 0)
476 		goto out;
477 
478 	sg_set_page(&db_tab->page[i].mem, pages[0], MTHCA_ICM_PAGE_SIZE,
479 			uaddr & ~PAGE_MASK);
480 
481 	ret = pci_map_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
482 	if (ret < 0) {
483 		put_page(pages[0]);
484 		goto out;
485 	}
486 
487 	ret = mthca_MAP_ICM_page(dev, sg_dma_address(&db_tab->page[i].mem),
488 				 mthca_uarc_virt(dev, uar, i));
489 	if (ret) {
490 		pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
491 		put_page(sg_page(&db_tab->page[i].mem));
492 		goto out;
493 	}
494 
495 	db_tab->page[i].uvirt    = uaddr;
496 	db_tab->page[i].refcount = 1;
497 
498 out:
499 	mutex_unlock(&db_tab->mutex);
500 	return ret;
501 }
502 
503 void mthca_unmap_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
504 			 struct mthca_user_db_table *db_tab, int index)
505 {
506 	if (!mthca_is_memfree(dev))
507 		return;
508 
509 	/*
510 	 * To make our bookkeeping simpler, we don't unmap DB
511 	 * pages until we clean up the whole db table.
512 	 */
513 
514 	mutex_lock(&db_tab->mutex);
515 
516 	--db_tab->page[index / MTHCA_DB_REC_PER_PAGE].refcount;
517 
518 	mutex_unlock(&db_tab->mutex);
519 }
520 
521 struct mthca_user_db_table *mthca_init_user_db_tab(struct mthca_dev *dev)
522 {
523 	struct mthca_user_db_table *db_tab;
524 	int npages;
525 	int i;
526 
527 	if (!mthca_is_memfree(dev))
528 		return NULL;
529 
530 	npages = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
531 	db_tab = kmalloc(sizeof *db_tab + npages * sizeof *db_tab->page, GFP_KERNEL);
532 	if (!db_tab)
533 		return ERR_PTR(-ENOMEM);
534 
535 	mutex_init(&db_tab->mutex);
536 	for (i = 0; i < npages; ++i) {
537 		db_tab->page[i].refcount = 0;
538 		db_tab->page[i].uvirt    = 0;
539 		sg_init_table(&db_tab->page[i].mem, 1);
540 	}
541 
542 	return db_tab;
543 }
544 
545 void mthca_cleanup_user_db_tab(struct mthca_dev *dev, struct mthca_uar *uar,
546 			       struct mthca_user_db_table *db_tab)
547 {
548 	int i;
549 
550 	if (!mthca_is_memfree(dev))
551 		return;
552 
553 	for (i = 0; i < dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE; ++i) {
554 		if (db_tab->page[i].uvirt) {
555 			mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, uar, i), 1);
556 			pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
557 			put_page(sg_page(&db_tab->page[i].mem));
558 		}
559 	}
560 
561 	kfree(db_tab);
562 }
563 
564 int mthca_alloc_db(struct mthca_dev *dev, enum mthca_db_type type,
565 		   u32 qn, __be32 **db)
566 {
567 	int group;
568 	int start, end, dir;
569 	int i, j;
570 	struct mthca_db_page *page;
571 	int ret = 0;
572 
573 	mutex_lock(&dev->db_tab->mutex);
574 
575 	switch (type) {
576 	case MTHCA_DB_TYPE_CQ_ARM:
577 	case MTHCA_DB_TYPE_SQ:
578 		group = 0;
579 		start = 0;
580 		end   = dev->db_tab->max_group1;
581 		dir   = 1;
582 		break;
583 
584 	case MTHCA_DB_TYPE_CQ_SET_CI:
585 	case MTHCA_DB_TYPE_RQ:
586 	case MTHCA_DB_TYPE_SRQ:
587 		group = 1;
588 		start = dev->db_tab->npages - 1;
589 		end   = dev->db_tab->min_group2;
590 		dir   = -1;
591 		break;
592 
593 	default:
594 		ret = -EINVAL;
595 		goto out;
596 	}
597 
598 	for (i = start; i != end; i += dir)
599 		if (dev->db_tab->page[i].db_rec &&
600 		    !bitmap_full(dev->db_tab->page[i].used,
601 				 MTHCA_DB_REC_PER_PAGE)) {
602 			page = dev->db_tab->page + i;
603 			goto found;
604 		}
605 
606 	for (i = start; i != end; i += dir)
607 		if (!dev->db_tab->page[i].db_rec) {
608 			page = dev->db_tab->page + i;
609 			goto alloc;
610 		}
611 
612 	if (dev->db_tab->max_group1 >= dev->db_tab->min_group2 - 1) {
613 		ret = -ENOMEM;
614 		goto out;
615 	}
616 
617 	if (group == 0)
618 		++dev->db_tab->max_group1;
619 	else
620 		--dev->db_tab->min_group2;
621 
622 	page = dev->db_tab->page + end;
623 
624 alloc:
625 	page->db_rec = dma_alloc_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
626 					  &page->mapping, GFP_KERNEL);
627 	if (!page->db_rec) {
628 		ret = -ENOMEM;
629 		goto out;
630 	}
631 	memset(page->db_rec, 0, MTHCA_ICM_PAGE_SIZE);
632 
633 	ret = mthca_MAP_ICM_page(dev, page->mapping,
634 				 mthca_uarc_virt(dev, &dev->driver_uar, i));
635 	if (ret) {
636 		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
637 				  page->db_rec, page->mapping);
638 		goto out;
639 	}
640 
641 	bitmap_zero(page->used, MTHCA_DB_REC_PER_PAGE);
642 
643 found:
644 	j = find_first_zero_bit(page->used, MTHCA_DB_REC_PER_PAGE);
645 	set_bit(j, page->used);
646 
647 	if (group == 1)
648 		j = MTHCA_DB_REC_PER_PAGE - 1 - j;
649 
650 	ret = i * MTHCA_DB_REC_PER_PAGE + j;
651 
652 	page->db_rec[j] = cpu_to_be64((qn << 8) | (type << 5));
653 
654 	*db = (__be32 *) &page->db_rec[j];
655 
656 out:
657 	mutex_unlock(&dev->db_tab->mutex);
658 
659 	return ret;
660 }
661 
662 void mthca_free_db(struct mthca_dev *dev, int type, int db_index)
663 {
664 	int i, j;
665 	struct mthca_db_page *page;
666 
667 	i = db_index / MTHCA_DB_REC_PER_PAGE;
668 	j = db_index % MTHCA_DB_REC_PER_PAGE;
669 
670 	page = dev->db_tab->page + i;
671 
672 	mutex_lock(&dev->db_tab->mutex);
673 
674 	page->db_rec[j] = 0;
675 	if (i >= dev->db_tab->min_group2)
676 		j = MTHCA_DB_REC_PER_PAGE - 1 - j;
677 	clear_bit(j, page->used);
678 
679 	if (bitmap_empty(page->used, MTHCA_DB_REC_PER_PAGE) &&
680 	    i >= dev->db_tab->max_group1 - 1) {
681 		mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1);
682 
683 		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
684 				  page->db_rec, page->mapping);
685 		page->db_rec = NULL;
686 
687 		if (i == dev->db_tab->max_group1) {
688 			--dev->db_tab->max_group1;
689 			/* XXX may be able to unmap more pages now */
690 		}
691 		if (i == dev->db_tab->min_group2)
692 			++dev->db_tab->min_group2;
693 	}
694 
695 	mutex_unlock(&dev->db_tab->mutex);
696 }
697 
698 int mthca_init_db_tab(struct mthca_dev *dev)
699 {
700 	int i;
701 
702 	if (!mthca_is_memfree(dev))
703 		return 0;
704 
705 	dev->db_tab = kmalloc(sizeof *dev->db_tab, GFP_KERNEL);
706 	if (!dev->db_tab)
707 		return -ENOMEM;
708 
709 	mutex_init(&dev->db_tab->mutex);
710 
711 	dev->db_tab->npages     = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
712 	dev->db_tab->max_group1 = 0;
713 	dev->db_tab->min_group2 = dev->db_tab->npages - 1;
714 
715 	dev->db_tab->page = kmalloc(dev->db_tab->npages *
716 				    sizeof *dev->db_tab->page,
717 				    GFP_KERNEL);
718 	if (!dev->db_tab->page) {
719 		kfree(dev->db_tab);
720 		return -ENOMEM;
721 	}
722 
723 	for (i = 0; i < dev->db_tab->npages; ++i)
724 		dev->db_tab->page[i].db_rec = NULL;
725 
726 	return 0;
727 }
728 
729 void mthca_cleanup_db_tab(struct mthca_dev *dev)
730 {
731 	int i;
732 
733 	if (!mthca_is_memfree(dev))
734 		return;
735 
736 	/*
737 	 * Because we don't always free our UARC pages when they
738 	 * become empty to make mthca_free_db() simpler we need to
739 	 * make a sweep through the doorbell pages and free any
740 	 * leftover pages now.
741 	 */
742 	for (i = 0; i < dev->db_tab->npages; ++i) {
743 		if (!dev->db_tab->page[i].db_rec)
744 			continue;
745 
746 		if (!bitmap_empty(dev->db_tab->page[i].used, MTHCA_DB_REC_PER_PAGE))
747 			mthca_warn(dev, "Kernel UARC page %d not empty\n", i);
748 
749 		mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1);
750 
751 		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
752 				  dev->db_tab->page[i].db_rec,
753 				  dev->db_tab->page[i].mapping);
754 	}
755 
756 	kfree(dev->db_tab->page);
757 	kfree(dev->db_tab);
758 }
759