drivers/infiniband/hw/mlx4/doorbell.c

   1 /*
   2  * Copyright (c) 2007 Cisco Systems, Inc. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32
  33 #include <linux/slab.h>
  34
  35 #include "mlx4_ib.h"
  36
  37 struct mlx4_ib_db_pgdir {
  38         struct list_head        list;
  39         DECLARE_BITMAP(order0, MLX4_IB_DB_PER_PAGE);
  40         DECLARE_BITMAP(order1, MLX4_IB_DB_PER_PAGE / 2);
  41         unsigned long          *bits[2];
  42         __be32                 *db_page;
  43         dma_addr_t              db_dma;
  44 };
  45
  46 static struct mlx4_ib_db_pgdir *mlx4_ib_alloc_db_pgdir(struct mlx4_ib_dev *dev)
  47 {
  48         struct mlx4_ib_db_pgdir *pgdir;
  49
  50         pgdir = kzalloc(sizeof *pgdir, GFP_KERNEL);
  51         if (!pgdir)
  52                 return NULL;
  53
  54         bitmap_fill(pgdir->order1, MLX4_IB_DB_PER_PAGE / 2);
  55         pgdir->bits[0] = pgdir->order0;
  56         pgdir->bits[1] = pgdir->order1;
  57         pgdir->db_page = dma_alloc_coherent(dev->ib_dev.dma_device,
  58                                             PAGE_SIZE, &pgdir->db_dma,
  59                                             GFP_KERNEL);
  60         if (!pgdir->db_page) {
  61                 kfree(pgdir);
  62                 return NULL;
  63         }
  64
  65         return pgdir;
  66 }
  67
  68 static int mlx4_ib_alloc_db_from_pgdir(struct mlx4_ib_db_pgdir *pgdir,
  69                                        struct mlx4_ib_db *db, int order)
  70 {
  71         int o;
  72         int i;
  73
  74         for (o = order; o <= 1; ++o) {
  75                 i = find_first_bit(pgdir->bits[o], MLX4_IB_DB_PER_PAGE >> o);
  76                 if (i < MLX4_IB_DB_PER_PAGE >> o)
  77                         goto found;
  78         }
  79
  80         return -ENOMEM;
  81
  82 found:
  83         clear_bit(i, pgdir->bits[o]);
  84
  85         i <<= o;
  86
  87         if (o > order)
  88                 set_bit(i ^ 1, pgdir->bits[order]);
  89
  90         db->u.pgdir = pgdir;
  91         db->index   = i;
  92         db->db      = pgdir->db_page + db->index;
  93         db->dma     = pgdir->db_dma  + db->index * 4;
  94         db->order   = order;
  95
  96         return 0;
  97 }
  98
  99 int mlx4_ib_db_alloc(struct mlx4_ib_dev *dev, struct mlx4_ib_db *db, int order)
 100 {
 101         struct mlx4_ib_db_pgdir *pgdir;
 102         int ret = 0;
 103
 104         mutex_lock(&dev->pgdir_mutex);
 105
 106         list_for_each_entry(pgdir, &dev->pgdir_list, list)
 107                 if (!mlx4_ib_alloc_db_from_pgdir(pgdir, db, order))
 108                         goto out;
 109
 110         pgdir = mlx4_ib_alloc_db_pgdir(dev);
 111         if (!pgdir) {
 112                 ret = -ENOMEM;
 113                 goto out;
 114         }
 115
 116         list_add(&pgdir->list, &dev->pgdir_list);
 117
 118         /* This should never fail -- we just allocated an empty page: */
 119         WARN_ON(mlx4_ib_alloc_db_from_pgdir(pgdir, db, order));
 120
 121 out:
 122         mutex_unlock(&dev->pgdir_mutex);
 123
 124         return ret;
 125 }
 126
 127 void mlx4_ib_db_free(struct mlx4_ib_dev *dev, struct mlx4_ib_db *db)
 128 {
 129         int o;
 130         int i;
 131
 132         mutex_lock(&dev->pgdir_mutex);
 133
 134         o = db->order;
 135         i = db->index;
 136
 137         if (db->order == 0 && test_bit(i ^ 1, db->u.pgdir->order0)) {
 138                 clear_bit(i ^ 1, db->u.pgdir->order0);
 139                 ++o;
 140         }
 141
 142         i >>= o;
 143         set_bit(i, db->u.pgdir->bits[o]);
 144
 145         if (bitmap_full(db->u.pgdir->order1, MLX4_IB_DB_PER_PAGE / 2)) {
 146                 dma_free_coherent(dev->ib_dev.dma_device, PAGE_SIZE,
 147                                   db->u.pgdir->db_page, db->u.pgdir->db_dma);
 148                 list_del(&db->u.pgdir->list);
 149                 kfree(db->u.pgdir);
 150         }
 151
 152         mutex_unlock(&dev->pgdir_mutex);
 153 }
 154
 155 struct mlx4_ib_user_db_page {
 156         struct list_head        list;
 157         struct ib_umem         *umem;
 158         unsigned long           user_virt;
 159         int                     refcnt;
 160 };
 161
 162 int mlx4_ib_db_map_user(struct mlx4_ib_ucontext *context, unsigned long virt,
 163                         struct mlx4_ib_db *db)
 164 {
 165         struct mlx4_ib_user_db_page *page;
 166         struct ib_umem_chunk *chunk;
 167         int err = 0;
 168
 169         mutex_lock(&context->db_page_mutex);
 170
 171         list_for_each_entry(page, &context->db_page_list, list)
 172                 if (page->user_virt == (virt & PAGE_MASK))
 173                         goto found;
 174
 175         page = kmalloc(sizeof *page, GFP_KERNEL);
 176         if (!page) {
 177                 err = -ENOMEM;
 178                 goto out;
 179         }
 180
 181         page->user_virt = (virt & PAGE_MASK);
 182         page->refcnt    = 0;
 183         page->umem      = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
 184                                       PAGE_SIZE, 0);
 185         if (IS_ERR(page->umem)) {
 186                 err = PTR_ERR(page->umem);
 187                 kfree(page);
 188                 goto out;
 189         }
 190
 191         list_add(&page->list, &context->db_page_list);
 192
 193 found:
 194         chunk = list_entry(page->umem->chunk_list.next, struct ib_umem_chunk, list);
 195         db->dma         = sg_dma_address(chunk->page_list) + (virt & ~PAGE_MASK);
 196         db->u.user_page = page;
 197         ++page->refcnt;
 198
 199 out:
 200         mutex_unlock(&context->db_page_mutex);
 201
 202         return err;
 203 }
 204
 205 void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_ib_db *db)
 206 {
 207         mutex_lock(&context->db_page_mutex);
 208
 209         if (!--db->u.user_page->refcnt) {
 210                 list_del(&db->u.user_page->list);
 211                 ib_umem_release(db->u.user_page->umem);
 212                 kfree(db->u.user_page);
 213         }
 214
 215         mutex_unlock(&context->db_page_mutex);
 216 }