drivers/char/drm/lists.c

   1 /* lists.c -- Buffer list handling routines -*- linux-c -*-
   2  * Created: Mon Apr 19 20:54:22 1999 by faith@precisioninsight.com
   3  * Revised: Fri Aug 20 09:27:01 1999 by faith@precisioninsight.com
   4  *
   5  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
   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  * PRECISION INSIGHT 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 OTHER
  25  * DEALINGS IN THE SOFTWARE.
  26  *
  27  * $PI: xc/programs/Xserver/hw/xfree86/os-support/linux/drm/generic/lists.c,v 1.3 1999/08/20 15:07:02 faith Exp $
  28  * $XFree86$
  29  *
  30  */
  31
  32 #define __NO_VERSION__
  33 #include "drmP.h"
  34
  35 int drm_waitlist_create(drm_waitlist_t *bl, int count)
  36 {
  37         DRM_DEBUG("%d\n", count);
  38         if (bl->count) return -EINVAL;
  39
  40         bl->count      = count;
  41         bl->bufs       = drm_alloc((bl->count + 2) * sizeof(*bl->bufs),
  42                                    DRM_MEM_BUFLISTS);
  43         bl->rp         = bl->bufs;
  44         bl->wp         = bl->bufs;
  45         bl->end        = &bl->bufs[bl->count+1];
  46         bl->write_lock = SPIN_LOCK_UNLOCKED;
  47         bl->read_lock  = SPIN_LOCK_UNLOCKED;
  48         return 0;
  49 }
  50
  51 int drm_waitlist_destroy(drm_waitlist_t *bl)
  52 {
  53         DRM_DEBUG("\n");
  54         if (bl->rp != bl->wp) return -EINVAL;
  55         if (bl->bufs) drm_free(bl->bufs,
  56                                (bl->count + 2) * sizeof(*bl->bufs),
  57                                DRM_MEM_BUFLISTS);
  58         bl->count = 0;
  59         bl->bufs  = NULL;
  60         bl->rp    = NULL;
  61         bl->wp    = NULL;
  62         bl->end   = NULL;
  63         return 0;
  64 }
  65
  66 int drm_waitlist_put(drm_waitlist_t *bl, drm_buf_t *buf)
  67 {
  68         int           left;
  69         unsigned long flags;
  70
  71         left = DRM_LEFTCOUNT(bl);
  72         DRM_DEBUG("put %d (%d left, rp = %p, wp = %p)\n",
  73                   buf->idx, left, bl->rp, bl->wp);
  74         if (!left) {
  75                 DRM_ERROR("Overflow while adding buffer %d from pid %d\n",
  76                           buf->idx, buf->pid);
  77                 return -EINVAL;
  78         }
  79 #if DRM_DMA_HISTOGRAM
  80         buf->time_queued = get_cycles();
  81 #endif
  82         buf->list        = DRM_LIST_WAIT;
  83
  84         spin_lock_irqsave(&bl->write_lock, flags);
  85         *bl->wp = buf;
  86         if (++bl->wp >= bl->end) bl->wp = bl->bufs;
  87         spin_unlock_irqrestore(&bl->write_lock, flags);
  88
  89         return 0;
  90 }
  91
  92 drm_buf_t *drm_waitlist_get(drm_waitlist_t *bl)
  93 {
  94         drm_buf_t     *buf;
  95         unsigned long flags;
  96
  97         spin_lock_irqsave(&bl->read_lock, flags);
  98         buf = *bl->rp;
  99         if (bl->rp == bl->wp) {
 100                 spin_unlock_irqrestore(&bl->read_lock, flags);
 101                 return NULL;
 102         }
 103         if (++bl->rp >= bl->end) bl->rp = bl->bufs;
 104         spin_unlock_irqrestore(&bl->read_lock, flags);
 105
 106         DRM_DEBUG("get %d\n", buf->idx);
 107         return buf;
 108 }
 109
 110 int drm_freelist_create(drm_freelist_t *bl, int count)
 111 {
 112         DRM_DEBUG("\n");
 113         atomic_set(&bl->count, 0);
 114         bl->next      = NULL;
 115         init_waitqueue_head(&bl->waiting);
 116         bl->low_mark  = 0;
 117         bl->high_mark = 0;
 118         atomic_set(&bl->wfh,   0);
 119         ++bl->initialized;
 120         return 0;
 121 }
 122
 123 int drm_freelist_destroy(drm_freelist_t *bl)
 124 {
 125         DRM_DEBUG("\n");
 126         atomic_set(&bl->count, 0);
 127         bl->next = NULL;
 128         return 0;
 129 }
 130
 131 int drm_freelist_put(drm_device_t *dev, drm_freelist_t *bl, drm_buf_t *buf)
 132 {
 133         unsigned int     old;
 134         unsigned int     new;
 135         char             failed;
 136         int              count = 0;
 137         drm_device_dma_t *dma = dev->dma;
 138
 139         if (!dma) {
 140                 DRM_ERROR("No DMA support\n");
 141                 return 1;
 142         }
 143
 144         if (buf->waiting || buf->pending || buf->list == DRM_LIST_FREE) {
 145                 DRM_ERROR("Freed buffer %d: w%d, p%d, l%d\n",
 146                           buf->idx, buf->waiting, buf->pending, buf->list);
 147         }
 148         DRM_DEBUG("%d, count = %d, wfh = %d, w%d, p%d\n",
 149                   buf->idx, atomic_read(&bl->count), atomic_read(&bl->wfh),
 150                   buf->waiting, buf->pending);
 151         if (!bl) return 1;
 152 #if DRM_DMA_HISTOGRAM
 153         buf->time_freed = get_cycles();
 154         drm_histogram_compute(dev, buf);
 155 #endif
 156         buf->list       = DRM_LIST_FREE;
 157         do {
 158                 old       = (unsigned long)bl->next;
 159                 buf->next = (void *)old;
 160                 new       = (unsigned long)buf;
 161                 _DRM_CAS(&bl->next, old, new, failed);
 162                 if (++count > DRM_LOOPING_LIMIT) {
 163                         DRM_ERROR("Looping\n");
 164                         return 1;
 165                 }
 166         } while (failed);
 167         atomic_inc(&bl->count);
 168         if (atomic_read(&bl->count) > dma->buf_count) {
 169                 DRM_ERROR("%d of %d buffers free after addition of %d\n",
 170                           atomic_read(&bl->count), dma->buf_count, buf->idx);
 171                 return 1;
 172         }
 173                                 /* Check for high water mark */
 174         if (atomic_read(&bl->wfh) && atomic_read(&bl->count)>=bl->high_mark) {
 175                 atomic_set(&bl->wfh, 0);
 176                 wake_up_interruptible(&bl->waiting);
 177         }
 178         return 0;
 179 }
 180
 181 static drm_buf_t *drm_freelist_try(drm_freelist_t *bl)
 182 {
 183         unsigned int      old;
 184         unsigned int      new;
 185         char              failed;
 186         drm_buf_t         *buf;
 187         int               count = 0;
 188
 189         if (!bl) return NULL;
 190
 191                                 /* Get buffer */
 192         do {
 193                 old = (unsigned int)bl->next;
 194                 if (!old) {
 195                         return NULL;
 196                 }
 197                 new = (unsigned long)bl->next->next;
 198                 _DRM_CAS(&bl->next, old, new, failed);
 199                 if (++count > DRM_LOOPING_LIMIT) {
 200                         DRM_ERROR("Looping\n");
 201                         return NULL;
 202                 }
 203         } while (failed);
 204         atomic_dec(&bl->count);
 205
 206         buf       = (drm_buf_t *)old;
 207         buf->next = NULL;
 208         buf->list = DRM_LIST_NONE;
 209         DRM_DEBUG("%d, count = %d, wfh = %d, w%d, p%d\n",
 210                   buf->idx, atomic_read(&bl->count), atomic_read(&bl->wfh),
 211                   buf->waiting, buf->pending);
 212         if (buf->waiting || buf->pending) {
 213                 DRM_ERROR("Free buffer %d: w%d, p%d, l%d\n",
 214                           buf->idx, buf->waiting, buf->pending, buf->list);
 215         }
 216
 217         return buf;
 218 }
 219
 220 drm_buf_t *drm_freelist_get(drm_freelist_t *bl, int block)
 221 {
 222         drm_buf_t         *buf  = NULL;
 223         DECLARE_WAITQUEUE(entry, current);
 224
 225         if (!bl || !bl->initialized) return NULL;
 226
 227                                 /* Check for low water mark */
 228         if (atomic_read(&bl->count) <= bl->low_mark) /* Became low */
 229                 atomic_set(&bl->wfh, 1);
 230         if (atomic_read(&bl->wfh)) {
 231                 DRM_DEBUG("Block = %d, count = %d, wfh = %d\n",
 232                           block, atomic_read(&bl->count),
 233                           atomic_read(&bl->wfh));
 234                 if (block) {
 235                         add_wait_queue(&bl->waiting, &entry);
 236                         current->state = TASK_INTERRUPTIBLE;
 237                         for (;;) {
 238                                 if (!atomic_read(&bl->wfh)
 239                                     && (buf = drm_freelist_try(bl))) break;
 240                                 schedule();
 241                                 if (signal_pending(current)) break;
 242                         }
 243                         current->state = TASK_RUNNING;
 244                         remove_wait_queue(&bl->waiting, &entry);
 245                 }
 246                 return buf;
 247         }
 248
 249         DRM_DEBUG("Count = %d, wfh = %d\n",
 250                   atomic_read(&bl->count), atomic_read(&bl->wfh));
 251         return drm_freelist_try(bl);
 252 }