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 
40 #include <asm/page.h>
41 
42 #include "mthca_memfree.h"
43 #include "mthca_dev.h"
44 #include "mthca_cmd.h"
45 
46 /*
47  * We allocate in as big chunks as we can, up to a maximum of 256 KB
48  * per chunk.
49  */
50 enum {
51 	MTHCA_ICM_ALLOC_SIZE   = 1 << 18,
52 	MTHCA_TABLE_CHUNK_SIZE = 1 << 18
53 };
54 
55 struct mthca_user_db_table {
56 	struct mutex mutex;
57 	struct {
58 		u64                uvirt;
59 		struct scatterlist mem;
60 		int                refcount;
61 	}                page[0];
62 };
63 
64 static void mthca_free_icm_pages(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
65 {
66 	int i;
67 
68 	if (chunk->nsg > 0)
69 		pci_unmap_sg(dev->pdev, chunk->mem, chunk->npages,
70 			     PCI_DMA_BIDIRECTIONAL);
71 
72 	for (i = 0; i < chunk->npages; ++i)
73 		__free_pages(sg_page(&chunk->mem[i]),
74 			     get_order(chunk->mem[i].length));
75 }
76 
77 static void mthca_free_icm_coherent(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
78 {
79 	int i;
80 
81 	for (i = 0; i < chunk->npages; ++i) {
82 		dma_free_coherent(&dev->pdev->dev, chunk->mem[i].length,
83 				  lowmem_page_address(sg_page(&chunk->mem[i])),
84 				  sg_dma_address(&chunk->mem[i]));
85 	}
86 }
87 
88 void mthca_free_icm(struct mthca_dev *dev, struct mthca_icm *icm, int coherent)
89 {
90 	struct mthca_icm_chunk *chunk, *tmp;
91 
92 	if (!icm)
93 		return;
94 
95 	list_for_each_entry_safe(chunk, tmp, &icm->chunk_list, list) {
96 		if (coherent)
97 			mthca_free_icm_coherent(dev, chunk);
98 		else
99 			mthca_free_icm_pages(dev, chunk);
100 
101 		kfree(chunk);
102 	}
103 
104 	kfree(icm);
105 }
106 
107 static int mthca_alloc_icm_pages(struct scatterlist *mem, int order, gfp_t gfp_mask)
108 {
109 	struct page *page;
110 
111 	/*
112 	 * Use __GFP_ZERO because buggy firmware assumes ICM pages are
113 	 * cleared, and subtle failures are seen if they aren't.
114 	 */
115 	page = alloc_pages(gfp_mask | __GFP_ZERO, order);
116 	if (!page)
117 		return -ENOMEM;
118 
119 	sg_set_page(mem, page, PAGE_SIZE << order, 0);
120 	return 0;
121 }
122 
123 static int mthca_alloc_icm_coherent(struct device *dev, struct scatterlist *mem,
124 				    int order, gfp_t gfp_mask)
125 {
126 	void *buf = dma_alloc_coherent(dev, PAGE_SIZE << order, &sg_dma_address(mem),
127 				       gfp_mask);
128 	if (!buf)
129 		return -ENOMEM;
130 
131 	sg_set_buf(mem, buf, PAGE_SIZE << order);
132 	BUG_ON(mem->offset);
133 	sg_dma_len(mem) = PAGE_SIZE << order;
134 	return 0;
135 }
136 
137 struct mthca_icm *mthca_alloc_icm(struct mthca_dev *dev, int npages,
138 				  gfp_t gfp_mask, int coherent)
139 {
140 	struct mthca_icm *icm;
141 	struct mthca_icm_chunk *chunk = NULL;
142 	int cur_order;
143 	int ret;
144 
145 	/* We use sg_set_buf for coherent allocs, which assumes low memory */
146 	BUG_ON(coherent && (gfp_mask & __GFP_HIGHMEM));
147 
148 	icm = kmalloc(sizeof *icm, gfp_mask & ~(__GFP_HIGHMEM | __GFP_NOWARN));
149 	if (!icm)
150 		return icm;
151 
152 	icm->refcount = 0;
153 	INIT_LIST_HEAD(&icm->chunk_list);
154 
155 	cur_order = get_order(MTHCA_ICM_ALLOC_SIZE);
156 
157 	while (npages > 0) {
158 		if (!chunk) {
159 			chunk = kmalloc(sizeof *chunk,
160 					gfp_mask & ~(__GFP_HIGHMEM | __GFP_NOWARN));
161 			if (!chunk)
162 				goto fail;
163 
164 			sg_init_table(chunk->mem, MTHCA_ICM_CHUNK_LEN);
165 			chunk->npages = 0;
166 			chunk->nsg    = 0;
167 			list_add_tail(&chunk->list, &icm->chunk_list);
168 		}
169 
170 		while (1 << cur_order > npages)
171 			--cur_order;
172 
173 		if (coherent)
174 			ret = mthca_alloc_icm_coherent(&dev->pdev->dev,
175 						       &chunk->mem[chunk->npages],
176 						       cur_order, gfp_mask);
177 		else
178 			ret = mthca_alloc_icm_pages(&chunk->mem[chunk->npages],
179 						    cur_order, gfp_mask);
180 
181 		if (!ret) {
182 			++chunk->npages;
183 
184 			if (coherent)
185 				++chunk->nsg;
186 			else if (chunk->npages == MTHCA_ICM_CHUNK_LEN) {
187 				chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
188 							chunk->npages,
189 							PCI_DMA_BIDIRECTIONAL);
190 
191 				if (chunk->nsg <= 0)
192 					goto fail;
193 			}
194 
195 			if (chunk->npages == MTHCA_ICM_CHUNK_LEN)
196 				chunk = NULL;
197 
198 			npages -= 1 << cur_order;
199 		} else {
200 			--cur_order;
201 			if (cur_order < 0)
202 				goto fail;
203 		}
204 	}
205 
206 	if (!coherent && chunk) {
207 		chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
208 					chunk->npages,
209 					PCI_DMA_BIDIRECTIONAL);
210 
211 		if (chunk->nsg <= 0)
212 			goto fail;
213 	}
214 
215 	return icm;
216 
217 fail:
218 	mthca_free_icm(dev, icm, coherent);
219 	return NULL;
220 }
221 
222 int mthca_table_get(struct mthca_dev *dev, struct mthca_icm_table *table, int obj)
223 {
224 	int i = (obj & (table->num_obj - 1)) * table->obj_size / MTHCA_TABLE_CHUNK_SIZE;
225 	int ret = 0;
226 
227 	mutex_lock(&table->mutex);
228 
229 	if (table->icm[i]) {
230 		++table->icm[i]->refcount;
231 		goto out;
232 	}
233 
234 	table->icm[i] = mthca_alloc_icm(dev, MTHCA_TABLE_CHUNK_SIZE >> PAGE_SHIFT,
235 					(table->lowmem ? GFP_KERNEL : GFP_HIGHUSER) |
236 					__GFP_NOWARN, table->coherent);
237 	if (!table->icm[i]) {
238 		ret = -ENOMEM;
239 		goto out;
240 	}
241 
242 	if (mthca_MAP_ICM(dev, table->icm[i],
243 			  table->virt + i * MTHCA_TABLE_CHUNK_SIZE)) {
244 		mthca_free_icm(dev, table->icm[i], table->coherent);
245 		table->icm[i] = NULL;
246 		ret = -ENOMEM;
247 		goto out;
248 	}
249 
250 	++table->icm[i]->refcount;
251 
252 out:
253 	mutex_unlock(&table->mutex);
254 	return ret;
255 }
256 
257 void mthca_table_put(struct mthca_dev *dev, struct mthca_icm_table *table, int obj)
258 {
259 	int i;
260 
261 	if (!mthca_is_memfree(dev))
262 		return;
263 
264 	i = (obj & (table->num_obj - 1)) * table->obj_size / MTHCA_TABLE_CHUNK_SIZE;
265 
266 	mutex_lock(&table->mutex);
267 
268 	if (--table->icm[i]->refcount == 0) {
269 		mthca_UNMAP_ICM(dev, table->virt + i * MTHCA_TABLE_CHUNK_SIZE,
270 				MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
271 		mthca_free_icm(dev, table->icm[i], table->coherent);
272 		table->icm[i] = NULL;
273 	}
274 
275 	mutex_unlock(&table->mutex);
276 }
277 
278 void *mthca_table_find(struct mthca_icm_table *table, int obj, dma_addr_t *dma_handle)
279 {
280 	int idx, offset, dma_offset, i;
281 	struct mthca_icm_chunk *chunk;
282 	struct mthca_icm *icm;
283 	struct page *page = NULL;
284 
285 	if (!table->lowmem)
286 		return NULL;
287 
288 	mutex_lock(&table->mutex);
289 
290 	idx = (obj & (table->num_obj - 1)) * table->obj_size;
291 	icm = table->icm[idx / MTHCA_TABLE_CHUNK_SIZE];
292 	dma_offset = offset = idx % MTHCA_TABLE_CHUNK_SIZE;
293 
294 	if (!icm)
295 		goto out;
296 
297 	list_for_each_entry(chunk, &icm->chunk_list, list) {
298 		for (i = 0; i < chunk->npages; ++i) {
299 			if (dma_handle && dma_offset >= 0) {
300 				if (sg_dma_len(&chunk->mem[i]) > dma_offset)
301 					*dma_handle = sg_dma_address(&chunk->mem[i]) +
302 						dma_offset;
303 				dma_offset -= sg_dma_len(&chunk->mem[i]);
304 			}
305 			/* DMA mapping can merge pages but not split them,
306 			 * so if we found the page, dma_handle has already
307 			 * been assigned to. */
308 			if (chunk->mem[i].length > offset) {
309 				page = sg_page(&chunk->mem[i]);
310 				goto out;
311 			}
312 			offset -= chunk->mem[i].length;
313 		}
314 	}
315 
316 out:
317 	mutex_unlock(&table->mutex);
318 	return page ? lowmem_page_address(page) + offset : NULL;
319 }
320 
321 int mthca_table_get_range(struct mthca_dev *dev, struct mthca_icm_table *table,
322 			  int start, int end)
323 {
324 	int inc = MTHCA_TABLE_CHUNK_SIZE / table->obj_size;
325 	int i, err;
326 
327 	for (i = start; i <= end; i += inc) {
328 		err = mthca_table_get(dev, table, i);
329 		if (err)
330 			goto fail;
331 	}
332 
333 	return 0;
334 
335 fail:
336 	while (i > start) {
337 		i -= inc;
338 		mthca_table_put(dev, table, i);
339 	}
340 
341 	return err;
342 }
343 
344 void mthca_table_put_range(struct mthca_dev *dev, struct mthca_icm_table *table,
345 			   int start, int end)
346 {
347 	int i;
348 
349 	if (!mthca_is_memfree(dev))
350 		return;
351 
352 	for (i = start; i <= end; i += MTHCA_TABLE_CHUNK_SIZE / table->obj_size)
353 		mthca_table_put(dev, table, i);
354 }
355 
356 struct mthca_icm_table *mthca_alloc_icm_table(struct mthca_dev *dev,
357 					      u64 virt, int obj_size,
358 					      int nobj, int reserved,
359 					      int use_lowmem, int use_coherent)
360 {
361 	struct mthca_icm_table *table;
362 	int obj_per_chunk;
363 	int num_icm;
364 	unsigned chunk_size;
365 	int i;
366 
367 	obj_per_chunk = MTHCA_TABLE_CHUNK_SIZE / obj_size;
368 	num_icm = DIV_ROUND_UP(nobj, obj_per_chunk);
369 
370 	table = kmalloc(struct_size(table, icm, num_icm), GFP_KERNEL);
371 	if (!table)
372 		return NULL;
373 
374 	table->virt     = virt;
375 	table->num_icm  = num_icm;
376 	table->num_obj  = nobj;
377 	table->obj_size = obj_size;
378 	table->lowmem   = use_lowmem;
379 	table->coherent = use_coherent;
380 	mutex_init(&table->mutex);
381 
382 	for (i = 0; i < num_icm; ++i)
383 		table->icm[i] = NULL;
384 
385 	for (i = 0; i * MTHCA_TABLE_CHUNK_SIZE < reserved * obj_size; ++i) {
386 		chunk_size = MTHCA_TABLE_CHUNK_SIZE;
387 		if ((i + 1) * MTHCA_TABLE_CHUNK_SIZE > nobj * obj_size)
388 			chunk_size = nobj * obj_size - i * MTHCA_TABLE_CHUNK_SIZE;
389 
390 		table->icm[i] = mthca_alloc_icm(dev, chunk_size >> PAGE_SHIFT,
391 						(use_lowmem ? GFP_KERNEL : GFP_HIGHUSER) |
392 						__GFP_NOWARN, use_coherent);
393 		if (!table->icm[i])
394 			goto err;
395 		if (mthca_MAP_ICM(dev, table->icm[i],
396 				  virt + i * MTHCA_TABLE_CHUNK_SIZE)) {
397 			mthca_free_icm(dev, table->icm[i], table->coherent);
398 			table->icm[i] = NULL;
399 			goto err;
400 		}
401 
402 		/*
403 		 * Add a reference to this ICM chunk so that it never
404 		 * gets freed (since it contains reserved firmware objects).
405 		 */
406 		++table->icm[i]->refcount;
407 	}
408 
409 	return table;
410 
411 err:
412 	for (i = 0; i < num_icm; ++i)
413 		if (table->icm[i]) {
414 			mthca_UNMAP_ICM(dev, virt + i * MTHCA_TABLE_CHUNK_SIZE,
415 					MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
416 			mthca_free_icm(dev, table->icm[i], table->coherent);
417 		}
418 
419 	kfree(table);
420 
421 	return NULL;
422 }
423 
424 void mthca_free_icm_table(struct mthca_dev *dev, struct mthca_icm_table *table)
425 {
426 	int i;
427 
428 	for (i = 0; i < table->num_icm; ++i)
429 		if (table->icm[i]) {
430 			mthca_UNMAP_ICM(dev,
431 					table->virt + i * MTHCA_TABLE_CHUNK_SIZE,
432 					MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
433 			mthca_free_icm(dev, table->icm[i], table->coherent);
434 		}
435 
436 	kfree(table);
437 }
438 
439 static u64 mthca_uarc_virt(struct mthca_dev *dev, struct mthca_uar *uar, int page)
440 {
441 	return dev->uar_table.uarc_base +
442 		uar->index * dev->uar_table.uarc_size +
443 		page * MTHCA_ICM_PAGE_SIZE;
444 }
445 
446 int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
447 		      struct mthca_user_db_table *db_tab, int index, u64 uaddr)
448 {
449 	struct page *pages[1];
450 	int ret = 0;
451 	int i;
452 
453 	if (!mthca_is_memfree(dev))
454 		return 0;
455 
456 	if (index < 0 || index > dev->uar_table.uarc_size / 8)
457 		return -EINVAL;
458 
459 	mutex_lock(&db_tab->mutex);
460 
461 	i = index / MTHCA_DB_REC_PER_PAGE;
462 
463 	if ((db_tab->page[i].refcount >= MTHCA_DB_REC_PER_PAGE)       ||
464 	    (db_tab->page[i].uvirt && db_tab->page[i].uvirt != uaddr) ||
465 	    (uaddr & 4095)) {
466 		ret = -EINVAL;
467 		goto out;
468 	}
469 
470 	if (db_tab->page[i].refcount) {
471 		++db_tab->page[i].refcount;
472 		goto out;
473 	}
474 
475 	ret = get_user_pages_fast(uaddr & PAGE_MASK, 1,
476 				  FOLL_WRITE | FOLL_LONGTERM, pages);
477 	if (ret < 0)
478 		goto out;
479 
480 	sg_set_page(&db_tab->page[i].mem, pages[0], MTHCA_ICM_PAGE_SIZE,
481 			uaddr & ~PAGE_MASK);
482 
483 	ret = pci_map_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
484 	if (ret < 0) {
485 		put_user_page(pages[0]);
486 		goto out;
487 	}
488 
489 	ret = mthca_MAP_ICM_page(dev, sg_dma_address(&db_tab->page[i].mem),
490 				 mthca_uarc_virt(dev, uar, i));
491 	if (ret) {
492 		pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
493 		put_user_page(sg_page(&db_tab->page[i].mem));
494 		goto out;
495 	}
496 
497 	db_tab->page[i].uvirt    = uaddr;
498 	db_tab->page[i].refcount = 1;
499 
500 out:
501 	mutex_unlock(&db_tab->mutex);
502 	return ret;
503 }
504 
505 void mthca_unmap_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
506 			 struct mthca_user_db_table *db_tab, int index)
507 {
508 	if (!mthca_is_memfree(dev))
509 		return;
510 
511 	/*
512 	 * To make our bookkeeping simpler, we don't unmap DB
513 	 * pages until we clean up the whole db table.
514 	 */
515 
516 	mutex_lock(&db_tab->mutex);
517 
518 	--db_tab->page[index / MTHCA_DB_REC_PER_PAGE].refcount;
519 
520 	mutex_unlock(&db_tab->mutex);
521 }
522 
523 struct mthca_user_db_table *mthca_init_user_db_tab(struct mthca_dev *dev)
524 {
525 	struct mthca_user_db_table *db_tab;
526 	int npages;
527 	int i;
528 
529 	if (!mthca_is_memfree(dev))
530 		return NULL;
531 
532 	npages = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
533 	db_tab = kmalloc(struct_size(db_tab, page, npages), GFP_KERNEL);
534 	if (!db_tab)
535 		return ERR_PTR(-ENOMEM);
536 
537 	mutex_init(&db_tab->mutex);
538 	for (i = 0; i < npages; ++i) {
539 		db_tab->page[i].refcount = 0;
540 		db_tab->page[i].uvirt    = 0;
541 		sg_init_table(&db_tab->page[i].mem, 1);
542 	}
543 
544 	return db_tab;
545 }
546 
547 void mthca_cleanup_user_db_tab(struct mthca_dev *dev, struct mthca_uar *uar,
548 			       struct mthca_user_db_table *db_tab)
549 {
550 	int i;
551 
552 	if (!mthca_is_memfree(dev))
553 		return;
554 
555 	for (i = 0; i < dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE; ++i) {
556 		if (db_tab->page[i].uvirt) {
557 			mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, uar, i), 1);
558 			pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
559 			put_user_page(sg_page(&db_tab->page[i].mem));
560 		}
561 	}
562 
563 	kfree(db_tab);
564 }
565 
566 int mthca_alloc_db(struct mthca_dev *dev, enum mthca_db_type type,
567 		   u32 qn, __be32 **db)
568 {
569 	int group;
570 	int start, end, dir;
571 	int i, j;
572 	struct mthca_db_page *page;
573 	int ret = 0;
574 
575 	mutex_lock(&dev->db_tab->mutex);
576 
577 	switch (type) {
578 	case MTHCA_DB_TYPE_CQ_ARM:
579 	case MTHCA_DB_TYPE_SQ:
580 		group = 0;
581 		start = 0;
582 		end   = dev->db_tab->max_group1;
583 		dir   = 1;
584 		break;
585 
586 	case MTHCA_DB_TYPE_CQ_SET_CI:
587 	case MTHCA_DB_TYPE_RQ:
588 	case MTHCA_DB_TYPE_SRQ:
589 		group = 1;
590 		start = dev->db_tab->npages - 1;
591 		end   = dev->db_tab->min_group2;
592 		dir   = -1;
593 		break;
594 
595 	default:
596 		ret = -EINVAL;
597 		goto out;
598 	}
599 
600 	for (i = start; i != end; i += dir)
601 		if (dev->db_tab->page[i].db_rec &&
602 		    !bitmap_full(dev->db_tab->page[i].used,
603 				 MTHCA_DB_REC_PER_PAGE)) {
604 			page = dev->db_tab->page + i;
605 			goto found;
606 		}
607 
608 	for (i = start; i != end; i += dir)
609 		if (!dev->db_tab->page[i].db_rec) {
610 			page = dev->db_tab->page + i;
611 			goto alloc;
612 		}
613 
614 	if (dev->db_tab->max_group1 >= dev->db_tab->min_group2 - 1) {
615 		ret = -ENOMEM;
616 		goto out;
617 	}
618 
619 	if (group == 0)
620 		++dev->db_tab->max_group1;
621 	else
622 		--dev->db_tab->min_group2;
623 
624 	page = dev->db_tab->page + end;
625 
626 alloc:
627 	page->db_rec = dma_alloc_coherent(&dev->pdev->dev,
628 					  MTHCA_ICM_PAGE_SIZE, &page->mapping,
629 					  GFP_KERNEL);
630 	if (!page->db_rec) {
631 		ret = -ENOMEM;
632 		goto out;
633 	}
634 
635 	ret = mthca_MAP_ICM_page(dev, page->mapping,
636 				 mthca_uarc_virt(dev, &dev->driver_uar, i));
637 	if (ret) {
638 		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
639 				  page->db_rec, page->mapping);
640 		goto out;
641 	}
642 
643 	bitmap_zero(page->used, MTHCA_DB_REC_PER_PAGE);
644 
645 found:
646 	j = find_first_zero_bit(page->used, MTHCA_DB_REC_PER_PAGE);
647 	set_bit(j, page->used);
648 
649 	if (group == 1)
650 		j = MTHCA_DB_REC_PER_PAGE - 1 - j;
651 
652 	ret = i * MTHCA_DB_REC_PER_PAGE + j;
653 
654 	page->db_rec[j] = cpu_to_be64((qn << 8) | (type << 5));
655 
656 	*db = (__be32 *) &page->db_rec[j];
657 
658 out:
659 	mutex_unlock(&dev->db_tab->mutex);
660 
661 	return ret;
662 }
663 
664 void mthca_free_db(struct mthca_dev *dev, int type, int db_index)
665 {
666 	int i, j;
667 	struct mthca_db_page *page;
668 
669 	i = db_index / MTHCA_DB_REC_PER_PAGE;
670 	j = db_index % MTHCA_DB_REC_PER_PAGE;
671 
672 	page = dev->db_tab->page + i;
673 
674 	mutex_lock(&dev->db_tab->mutex);
675 
676 	page->db_rec[j] = 0;
677 	if (i >= dev->db_tab->min_group2)
678 		j = MTHCA_DB_REC_PER_PAGE - 1 - j;
679 	clear_bit(j, page->used);
680 
681 	if (bitmap_empty(page->used, MTHCA_DB_REC_PER_PAGE) &&
682 	    i >= dev->db_tab->max_group1 - 1) {
683 		mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1);
684 
685 		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
686 				  page->db_rec, page->mapping);
687 		page->db_rec = NULL;
688 
689 		if (i == dev->db_tab->max_group1) {
690 			--dev->db_tab->max_group1;
691 			/* XXX may be able to unmap more pages now */
692 		}
693 		if (i == dev->db_tab->min_group2)
694 			++dev->db_tab->min_group2;
695 	}
696 
697 	mutex_unlock(&dev->db_tab->mutex);
698 }
699 
700 int mthca_init_db_tab(struct mthca_dev *dev)
701 {
702 	int i;
703 
704 	if (!mthca_is_memfree(dev))
705 		return 0;
706 
707 	dev->db_tab = kmalloc(sizeof *dev->db_tab, GFP_KERNEL);
708 	if (!dev->db_tab)
709 		return -ENOMEM;
710 
711 	mutex_init(&dev->db_tab->mutex);
712 
713 	dev->db_tab->npages     = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
714 	dev->db_tab->max_group1 = 0;
715 	dev->db_tab->min_group2 = dev->db_tab->npages - 1;
716 
717 	dev->db_tab->page = kmalloc_array(dev->db_tab->npages,
718 					  sizeof(*dev->db_tab->page),
719 					  GFP_KERNEL);
720 	if (!dev->db_tab->page) {
721 		kfree(dev->db_tab);
722 		return -ENOMEM;
723 	}
724 
725 	for (i = 0; i < dev->db_tab->npages; ++i)
726 		dev->db_tab->page[i].db_rec = NULL;
727 
728 	return 0;
729 }
730 
731 void mthca_cleanup_db_tab(struct mthca_dev *dev)
732 {
733 	int i;
734 
735 	if (!mthca_is_memfree(dev))
736 		return;
737 
738 	/*
739 	 * Because we don't always free our UARC pages when they
740 	 * become empty to make mthca_free_db() simpler we need to
741 	 * make a sweep through the doorbell pages and free any
742 	 * leftover pages now.
743 	 */
744 	for (i = 0; i < dev->db_tab->npages; ++i) {
745 		if (!dev->db_tab->page[i].db_rec)
746 			continue;
747 
748 		if (!bitmap_empty(dev->db_tab->page[i].used, MTHCA_DB_REC_PER_PAGE))
749 			mthca_warn(dev, "Kernel UARC page %d not empty\n", i);
750 
751 		mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1);
752 
753 		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
754 				  dev->db_tab->page[i].db_rec,
755 				  dev->db_tab->page[i].mapping);
756 	}
757 
758 	kfree(dev->db_tab->page);
759 	kfree(dev->db_tab);
760 }
761