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-queue.h"
  27 #include "cx18-streams.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 struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
  46                                  struct cx18_queue *q, int to_front)
  47 {
  48         /* clear the buffer if it is not to be enqueued to the full queue */
  49         if (q != &s->q_full) {
  50                 buf->bytesused = 0;
  51                 buf->readpos = 0;
  52                 buf->b_flags = 0;
  53                 buf->skipped = 0;
  54         }
  55
  56         /* q_busy is restricted to a max buffer count imposed by firmware */
  57         if (q == &s->q_busy &&
  58             atomic_read(&q->buffers) >= CX18_MAX_FW_MDLS_PER_STREAM)
  59                 q = &s->q_free;
  60
  61         spin_lock(&q->lock);
  62
  63         if (to_front)
  64                 list_add(&buf->list, &q->list); /* LIFO */
  65         else
  66                 list_add_tail(&buf->list, &q->list); /* FIFO */
  67         q->bytesused += buf->bytesused - buf->readpos;
  68         atomic_inc(&q->buffers);
  69
  70         spin_unlock(&q->lock);
  71         return q;
  72 }
  73
  74 struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
  75 {
  76         struct cx18_buffer *buf = NULL;
  77
  78         spin_lock(&q->lock);
  79         if (!list_empty(&q->list)) {
  80                 buf = list_first_entry(&q->list, struct cx18_buffer, list);
  81                 list_del_init(&buf->list);
  82                 q->bytesused -= buf->bytesused - buf->readpos;
  83                 buf->skipped = 0;
  84                 atomic_dec(&q->buffers);
  85         }
  86         spin_unlock(&q->lock);
  87         return buf;
  88 }
  89
  90 struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
  91         u32 bytesused)
  92 {
  93         struct cx18 *cx = s->cx;
  94         struct cx18_buffer *buf;
  95         struct cx18_buffer *tmp;
  96         struct cx18_buffer *ret = NULL;
  97         LIST_HEAD(sweep_up);
  98
  99         /*
 100          * We don't have to acquire multiple q locks here, because we are
 101          * serialized by the single threaded work handler.
 102          * Buffers from the firmware will thus remain in order as
 103          * they are moved from q_busy to q_full or to the dvb ring buffer.
 104          */
 105         spin_lock(&s->q_busy.lock);
 106         list_for_each_entry_safe(buf, tmp, &s->q_busy.list, list) {
 107                 /*
 108                  * We should find what the firmware told us is done,
 109                  * right at the front of the queue.  If we don't, we likely have
 110                  * missed a buffer done message from the firmware.
 111                  * Once we skip a buffer repeatedly, relative to the size of
 112                  * q_busy, we have high confidence we've missed it.
 113                  */
 114                 if (buf->id != id) {
 115                         buf->skipped++;
 116                         if (buf->skipped >= atomic_read(&s->q_busy.buffers)-1) {
 117                                 /* buffer must have fallen out of rotation */
 118                                 CX18_WARN("Skipped %s, buffer %d, %d "
 119                                           "times - it must have dropped out of "
 120                                           "rotation\n", s->name, buf->id,
 121                                           buf->skipped);
 122                                 /* Sweep it up to put it back into rotation */
 123                                 list_move_tail(&buf->list, &sweep_up);
 124                                 atomic_dec(&s->q_busy.buffers);
 125                         }
 126                         continue;
 127                 }
 128                 /*
 129                  * We pull the desired buffer off of the queue here.  Something
 130                  * will have to put it back on a queue later.
 131                  */
 132                 list_del_init(&buf->list);
 133                 atomic_dec(&s->q_busy.buffers);
 134                 ret = buf;
 135                 break;
 136         }
 137         spin_unlock(&s->q_busy.lock);
 138
 139         /*
 140          * We found the buffer for which we were looking.  Get it ready for
 141          * the caller to put on q_full or in the dvb ring buffer.
 142          */
 143         if (ret != NULL) {
 144                 ret->bytesused = bytesused;
 145                 ret->skipped = 0;
 146                 /* readpos and b_flags were 0'ed when the buf went on q_busy */
 147                 cx18_buf_sync_for_cpu(s, ret);
 148                 if (s->type != CX18_ENC_STREAM_TYPE_TS)
 149                         set_bit(CX18_F_B_NEED_BUF_SWAP, &ret->b_flags);
 150         }
 151
 152         /* Put any buffers the firmware is ignoring back into normal rotation */
 153         list_for_each_entry_safe(buf, tmp, &sweep_up, list) {
 154                 list_del_init(&buf->list);
 155                 cx18_enqueue(s, buf, &s->q_free);
 156         }
 157         return ret;
 158 }
 159
 160 /* Move all buffers of a queue to q_free, while flushing the buffers */
 161 static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
 162 {
 163         struct cx18_buffer *buf;
 164
 165         if (q == &s->q_free)
 166                 return;
 167
 168         spin_lock(&q->lock);
 169         while (!list_empty(&q->list)) {
 170                 buf = list_first_entry(&q->list, struct cx18_buffer, list);
 171                 list_move_tail(&buf->list, &s->q_free.list);
 172                 buf->bytesused = buf->readpos = buf->b_flags = buf->skipped = 0;
 173                 atomic_inc(&s->q_free.buffers);
 174         }
 175         cx18_queue_init(q);
 176         spin_unlock(&q->lock);
 177 }
 178
 179 void cx18_flush_queues(struct cx18_stream *s)
 180 {
 181         cx18_queue_flush(s, &s->q_busy);
 182         cx18_queue_flush(s, &s->q_full);
 183 }
 184
 185 int cx18_stream_alloc(struct cx18_stream *s)
 186 {
 187         struct cx18 *cx = s->cx;
 188         int i;
 189
 190         if (s->buffers == 0)
 191                 return 0;
 192
 193         CX18_DEBUG_INFO("Allocate %s stream: %d x %d buffers (%dkB total)\n",
 194                 s->name, s->buffers, s->buf_size,
 195                 s->buffers * s->buf_size / 1024);
 196
 197         if (((char __iomem *)&cx->scb->cpu_mdl[cx->mdl_offset + s->buffers] -
 198                                 (char __iomem *)cx->scb) > SCB_RESERVED_SIZE) {
 199                 unsigned bufsz = (((char __iomem *)cx->scb) + SCB_RESERVED_SIZE -
 200                                         ((char __iomem *)cx->scb->cpu_mdl));
 201
 202                 CX18_ERR("Too many buffers, cannot fit in SCB area\n");
 203                 CX18_ERR("Max buffers = %zd\n",
 204                         bufsz / sizeof(struct cx18_mdl));
 205                 return -ENOMEM;
 206         }
 207
 208         s->mdl_offset = cx->mdl_offset;
 209
 210         /* allocate stream buffers. Initially all buffers are in q_free. */
 211         for (i = 0; i < s->buffers; i++) {
 212                 struct cx18_buffer *buf = kzalloc(sizeof(struct cx18_buffer),
 213                                                 GFP_KERNEL|__GFP_NOWARN);
 214
 215                 if (buf == NULL)
 216                         break;
 217                 buf->buf = kmalloc(s->buf_size, GFP_KERNEL|__GFP_NOWARN);
 218                 if (buf->buf == NULL) {
 219                         kfree(buf);
 220                         break;
 221                 }
 222                 buf->id = cx->buffer_id++;
 223                 INIT_LIST_HEAD(&buf->list);
 224                 buf->dma_handle = pci_map_single(s->cx->pci_dev,
 225                                 buf->buf, s->buf_size, s->dma);
 226                 cx18_buf_sync_for_cpu(s, buf);
 227                 cx18_enqueue(s, buf, &s->q_free);
 228         }
 229         if (i == s->buffers) {
 230                 cx->mdl_offset += s->buffers;
 231                 return 0;
 232         }
 233         CX18_ERR("Couldn't allocate buffers for %s stream\n", s->name);
 234         cx18_stream_free(s);
 235         return -ENOMEM;
 236 }
 237
 238 void cx18_stream_free(struct cx18_stream *s)
 239 {
 240         struct cx18_buffer *buf;
 241
 242         /* move all buffers to q_free */
 243         cx18_flush_queues(s);
 244
 245         /* empty q_free */
 246         while ((buf = cx18_dequeue(s, &s->q_free))) {
 247                 pci_unmap_single(s->cx->pci_dev, buf->dma_handle,
 248                                 s->buf_size, s->dma);
 249                 kfree(buf->buf);
 250                 kfree(buf);
 251         }
 252 }