drivers/char/drm/gamma_lists.h

   1 /* drm_lists.h -- Buffer list handling routines -*- linux-c -*-
   2  * Created: Mon Apr 19 20:54:22 1999 by faith@valinux.com
   3  *
   4  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
   5  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
   6  * All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the next
  16  * paragraph) shall be included in all copies or substantial portions of the
  17  * Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  23  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  24  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  25  * OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  * Authors:
  28  *    Rickard E. (Rik) Faith <faith@valinux.com>
  29  *    Gareth Hughes <gareth@valinux.com>
  30  */
  31
  32 #include "drmP.h"
  33
  34
  35 int DRM(waitlist_create)(drm_waitlist_t *bl, int count)
  36 {
  37         if (bl->count) return -EINVAL;
  38
  39         bl->bufs       = DRM(alloc)((bl->count + 2) * sizeof(*bl->bufs),
  40                                     DRM_MEM_BUFLISTS);
  41
  42         if(!bl->bufs) return -ENOMEM;
  43         memset(bl->bufs, 0, sizeof(*bl->bufs));
  44         bl->count      = count;
  45         bl->rp         = bl->bufs;
  46         bl->wp         = bl->bufs;
  47         bl->end        = &bl->bufs[bl->count+1];
  48         spin_lock_init(&bl->write_lock);
  49         spin_lock_init(&bl->read_lock);
  50         return 0;
  51 }
  52
  53 int DRM(waitlist_destroy)(drm_waitlist_t *bl)
  54 {
  55         if (bl->rp != bl->wp) return -EINVAL;
  56         if (bl->bufs) DRM(free)(bl->bufs,
  57                                 (bl->count + 2) * sizeof(*bl->bufs),
  58                                 DRM_MEM_BUFLISTS);
  59         bl->count = 0;
  60         bl->bufs  = NULL;
  61         bl->rp    = NULL;
  62         bl->wp    = NULL;
  63         bl->end   = NULL;
  64         return 0;
  65 }
  66
  67 int DRM(waitlist_put)(drm_waitlist_t *bl, drm_buf_t *buf)
  68 {
  69         int           left;
  70         unsigned long flags;
  71
  72         left = DRM_LEFTCOUNT(bl);
  73         if (!left) {
  74                 DRM_ERROR("Overflow while adding buffer %d from filp %p\n",
  75                           buf->idx, buf->filp);
  76                 return -EINVAL;
  77         }
  78         buf->list        = DRM_LIST_WAIT;
  79
  80         spin_lock_irqsave(&bl->write_lock, flags);
  81         *bl->wp = buf;
  82         if (++bl->wp >= bl->end) bl->wp = bl->bufs;
  83         spin_unlock_irqrestore(&bl->write_lock, flags);
  84
  85         return 0;
  86 }
  87
  88 drm_buf_t *DRM(waitlist_get)(drm_waitlist_t *bl)
  89 {
  90         drm_buf_t     *buf;
  91         unsigned long flags;
  92
  93         spin_lock_irqsave(&bl->read_lock, flags);
  94         buf = *bl->rp;
  95         if (bl->rp == bl->wp) {
  96                 spin_unlock_irqrestore(&bl->read_lock, flags);
  97                 return NULL;
  98         }
  99         if (++bl->rp >= bl->end) bl->rp = bl->bufs;
 100         spin_unlock_irqrestore(&bl->read_lock, flags);
 101
 102         return buf;
 103 }
 104
 105 int DRM(freelist_create)(drm_freelist_t *bl, int count)
 106 {
 107         atomic_set(&bl->count, 0);
 108         bl->next      = NULL;
 109         init_waitqueue_head(&bl->waiting);
 110         bl->low_mark  = 0;
 111         bl->high_mark = 0;
 112         atomic_set(&bl->wfh,   0);
 113         spin_lock_init(&bl->lock);
 114         ++bl->initialized;
 115         return 0;
 116 }
 117
 118 int DRM(freelist_destroy)(drm_freelist_t *bl)
 119 {
 120         atomic_set(&bl->count, 0);
 121         bl->next = NULL;
 122         return 0;
 123 }
 124
 125 int DRM(freelist_put)(drm_device_t *dev, drm_freelist_t *bl, drm_buf_t *buf)
 126 {
 127         drm_device_dma_t *dma  = dev->dma;
 128
 129         if (!dma) {
 130                 DRM_ERROR("No DMA support\n");
 131                 return 1;
 132         }
 133
 134         if (buf->waiting || buf->pending || buf->list == DRM_LIST_FREE) {
 135                 DRM_ERROR("Freed buffer %d: w%d, p%d, l%d\n",
 136                           buf->idx, buf->waiting, buf->pending, buf->list);
 137         }
 138         if (!bl) return 1;
 139         buf->list       = DRM_LIST_FREE;
 140
 141         spin_lock(&bl->lock);
 142         buf->next       = bl->next;
 143         bl->next        = buf;
 144         spin_unlock(&bl->lock);
 145
 146         atomic_inc(&bl->count);
 147         if (atomic_read(&bl->count) > dma->buf_count) {
 148                 DRM_ERROR("%d of %d buffers free after addition of %d\n",
 149                           atomic_read(&bl->count), dma->buf_count, buf->idx);
 150                 return 1;
 151         }
 152                                 /* Check for high water mark */
 153         if (atomic_read(&bl->wfh) && atomic_read(&bl->count)>=bl->high_mark) {
 154                 atomic_set(&bl->wfh, 0);
 155                 wake_up_interruptible(&bl->waiting);
 156         }
 157         return 0;
 158 }
 159
 160 static drm_buf_t *DRM(freelist_try)(drm_freelist_t *bl)
 161 {
 162         drm_buf_t         *buf;
 163
 164         if (!bl) return NULL;
 165
 166                                 /* Get buffer */
 167         spin_lock(&bl->lock);
 168         if (!bl->next) {
 169                 spin_unlock(&bl->lock);
 170                 return NULL;
 171         }
 172         buf       = bl->next;
 173         bl->next  = bl->next->next;
 174         spin_unlock(&bl->lock);
 175
 176         atomic_dec(&bl->count);
 177         buf->next = NULL;
 178         buf->list = DRM_LIST_NONE;
 179         if (buf->waiting || buf->pending) {
 180                 DRM_ERROR("Free buffer %d: w%d, p%d, l%d\n",
 181                           buf->idx, buf->waiting, buf->pending, buf->list);
 182         }
 183
 184         return buf;
 185 }
 186
 187 drm_buf_t *DRM(freelist_get)(drm_freelist_t *bl, int block)
 188 {
 189         drm_buf_t         *buf  = NULL;
 190         DECLARE_WAITQUEUE(entry, current);
 191
 192         if (!bl || !bl->initialized) return NULL;
 193
 194                                 /* Check for low water mark */
 195         if (atomic_read(&bl->count) <= bl->low_mark) /* Became low */
 196                 atomic_set(&bl->wfh, 1);
 197         if (atomic_read(&bl->wfh)) {
 198                 if (block) {
 199                         add_wait_queue(&bl->waiting, &entry);
 200                         for (;;) {
 201                                 current->state = TASK_INTERRUPTIBLE;
 202                                 if (!atomic_read(&bl->wfh)
 203                                     && (buf = DRM(freelist_try)(bl))) break;
 204                                 schedule();
 205                                 if (signal_pending(current)) break;
 206                         }
 207                         current->state = TASK_RUNNING;
 208                         remove_wait_queue(&bl->waiting, &entry);
 209                 }
 210                 return buf;
 211         }
 212
 213         return DRM(freelist_try)(bl);
 214 }
 215