sys/dev/mthca/mthca_memfree.c

   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 }