git.oblomov.eu Git - linux-2.6/blob - drivers/media/video/cx18/cx18-queue.c

   1 /*
   2  *  cx18 buffer queues
   3  *
   4  *  Derived from ivtv-queue.c
   5  *
   6  *  Copyright (C) 2007  Hans Verkuil <hverkuil@xs4all.nl>
   7  *  Copyright (C) 2008  Andy Walls <awalls@radix.net>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to the Free Software
  21  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  22  *  02111-1307  USA
  23  */
  24
  25 #include "cx18-driver.h"
  26 #include "cx18-streams.h"
  27 #include "cx18-queue.h"
  28 #include "cx18-scb.h"
  29
  30 void cx18_buf_swap(struct cx18_buffer *buf)
  31 {
  32         int i;
  33
  34         for (i = 0; i < buf->bytesused; i += 4)
  35                 swab32s((u32 *)(buf->buf + i));
  36 }
  37
  38 void cx18_queue_init(struct cx18_queue *q)
  39 {
  40         INIT_LIST_HEAD(&q->list);
  41         atomic_set(&q->buffers, 0);
  42         q->bytesused = 0;
  43 }
  44
  45 void cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
  46                 struct cx18_queue *q)
  47 {
  48         /* clear the buffer if it is going to be enqueued to the free queue */
  49         if (q == &s->q_free) {
  50                 buf->bytesused = 0;
  51                 buf->readpos = 0;
  52                 buf->b_flags = 0;
  53                 buf->skipped = 0;
  54         }
  55         mutex_lock(&s->qlock);
  56         list_add_tail(&buf->list, &q->list);
  57         atomic_inc(&q->buffers);
  58         q->bytesused += buf->bytesused - buf->readpos;
  59         mutex_unlock(&s->qlock);
  60 }
  61
  62 struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
  63 {
  64         struct cx18_buffer *buf = NULL;
  65
  66         mutex_lock(&s->qlock);
  67         if (!list_empty(&q->list)) {
  68                 buf = list_entry(q->list.next, struct cx18_buffer, list);
  69                 list_del_init(q->list.next);
  70                 atomic_dec(&q->buffers);
  71                 q->bytesused -= buf->bytesused - buf->readpos;
  72                 buf->skipped = 0;
  73         }
  74         mutex_unlock(&s->qlock);
  75         return buf;
  76 }
  77
  78 struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
  79         u32 bytesused)
  80 {
  81         struct cx18 *cx = s->cx;
  82         struct cx18_buffer *buf;
  83         struct cx18_buffer *ret = NULL;
  84         struct list_head *p, *t;
  85         LIST_HEAD(r);
  86
  87         mutex_lock(&s->qlock);
  88         list_for_each_safe(p, t, &s->q_free.list) {
  89                 buf = list_entry(p, struct cx18_buffer, list);
  90
  91                 if (buf->id != id) {
  92                         buf->skipped++;
  93                         if (buf->skipped >= atomic_read(&s->q_free.buffers)-1) {
  94                                 /* buffer must have fallen out of rotation */
  95                                 atomic_dec(&s->q_free.buffers);
  96                                 list_move_tail(&buf->list, &r);
  97                                 CX18_WARN("Skipped %s, buffer %d, %d "
  98                                           "times - it must have dropped out of "
  99                                           "rotation\n", s->name, buf->id,
 100                                           buf->skipped);
 101                         }
 102                         continue;
 103                 }
 104
 105                 buf->bytesused = bytesused;
 106                 atomic_dec(&s->q_free.buffers);
 107                 if (s->type == CX18_ENC_STREAM_TYPE_TS) {
 108                         /*
 109                          * TS doesn't use q_full, but for sweeping up lost
 110                          * buffers, we want the TS to requeue the buffer just
 111                          * before sending the MDL back to the firmware, so we
 112                          * pull it off the list here.
 113                          */
 114                         list_del_init(&buf->list);
 115                 } else {
 116                         atomic_inc(&s->q_full.buffers);
 117                         s->q_full.bytesused += buf->bytesused;
 118                         list_move_tail(&buf->list, &s->q_full.list);
 119                 }
 120
 121                 ret = buf;
 122                 break;
 123         }
 124         mutex_unlock(&s->qlock);
 125
 126         /* Put lost buffers back into firmware transfer rotation */
 127         while (!list_empty(&r)) {
 128                 buf = list_entry(r.next, struct cx18_buffer, list);
 129                 list_del_init(r.next);
 130                 cx18_enqueue(s, buf, &s->q_free);
 131                 cx18_vapi(cx, CX18_CPU_DE_SET_MDL, 5, s->handle,
 132                        (void __iomem *)&cx->scb->cpu_mdl[buf->id] - cx->enc_mem,
 133                        1, buf->id, s->buf_size);
 134                 CX18_INFO("Returning %s, buffer %d back to transfer rotation\n",
 135                           s->name, buf->id);
 136                 /* and there was much rejoicing... */
 137         }
 138         return ret;
 139 }
 140
 141 /* Move all buffers of a queue to q_free, while flushing the buffers */
 142 static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
 143 {
 144         struct cx18_buffer *buf;
 145
 146         if (q == &s->q_free)
 147                 return;
 148
 149         mutex_lock(&s->qlock);
 150         while (!list_empty(&q->list)) {
 151                 buf = list_entry(q->list.next, struct cx18_buffer, list);
 152                 list_move_tail(q->list.next, &s->q_free.list);
 153                 buf->bytesused = buf->readpos = buf->b_flags = buf->skipped = 0;
 154                 atomic_inc(&s->q_free.buffers);
 155         }
 156         cx18_queue_init(q);
 157         mutex_unlock(&s->qlock);
 158 }
 159
 160 void cx18_flush_queues(struct cx18_stream *s)
 161 {
 162         cx18_queue_flush(s, &s->q_io);
 163         cx18_queue_flush(s, &s->q_full);
 164 }
 165
 166 int cx18_stream_alloc(struct cx18_stream *s)
 167 {
 168         struct cx18 *cx = s->cx;
 169         int i;
 170
 171         if (s->buffers == 0)
 172                 return 0;
 173
 174         CX18_DEBUG_INFO("Allocate %s stream: %d x %d buffers (%dkB total)\n",
 175                 s->name, s->buffers, s->buf_size,
 176                 s->buffers * s->buf_size / 1024);
 177
 178         if (((char __iomem *)&cx->scb->cpu_mdl[cx->mdl_offset + s->buffers] -
 179                                 (char __iomem *)cx->scb) > SCB_RESERVED_SIZE) {
 180                 unsigned bufsz = (((char __iomem *)cx->scb) + SCB_RESERVED_SIZE -
 181                                         ((char __iomem *)cx->scb->cpu_mdl));
 182
 183                 CX18_ERR("Too many buffers, cannot fit in SCB area\n");
 184                 CX18_ERR("Max buffers = %zd\n",
 185                         bufsz / sizeof(struct cx18_mdl));
 186                 return -ENOMEM;
 187         }
 188
 189         s->mdl_offset = cx->mdl_offset;
 190
 191         /* allocate stream buffers. Initially all buffers are in q_free. */
 192         for (i = 0; i < s->buffers; i++) {
 193                 struct cx18_buffer *buf = kzalloc(sizeof(struct cx18_buffer),
 194                                                 GFP_KERNEL|__GFP_NOWARN);
 195
 196                 if (buf == NULL)
 197                         break;
 198                 buf->buf = kmalloc(s->buf_size, GFP_KERNEL|__GFP_NOWARN);
 199                 if (buf->buf == NULL) {
 200                         kfree(buf);
 201                         break;
 202                 }
 203                 buf->id = cx->buffer_id++;
 204                 INIT_LIST_HEAD(&buf->list);
 205                 buf->dma_handle = pci_map_single(s->cx->dev,
 206                                 buf->buf, s->buf_size, s->dma);
 207                 cx18_buf_sync_for_cpu(s, buf);
 208                 cx18_enqueue(s, buf, &s->q_free);
 209         }
 210         if (i == s->buffers) {
 211                 cx->mdl_offset += s->buffers;
 212                 return 0;
 213         }
 214         CX18_ERR("Couldn't allocate buffers for %s stream\n", s->name);
 215         cx18_stream_free(s);
 216         return -ENOMEM;
 217 }
 218
 219 void cx18_stream_free(struct cx18_stream *s)
 220 {
 221         struct cx18_buffer *buf;
 222
 223         /* move all buffers to q_free */
 224         cx18_flush_queues(s);
 225
 226         /* empty q_free */
 227         while ((buf = cx18_dequeue(s, &s->q_free))) {
 228                 pci_unmap_single(s->cx->dev, buf->dma_handle,
 229                                 s->buf_size, s->dma);
 230                 kfree(buf->buf);
 231                 kfree(buf);
 232         }
 233 }