release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/media/video/em28xx/em28xx-vbi.c

   1 /*
   2    em28xx-vbi.c - VBI driver for em28xx
   3
   4    Copyright (C) 2009 Devin Heitmueller <dheitmueller@kernellabs.com>
   5
   6    This work was sponsored by EyeMagnet Limited.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  21    02110-1301, USA.
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/init.h>
  27
  28 #include "em28xx.h"
  29
  30 static unsigned int vbibufs = 5;
  31 module_param(vbibufs, int, 0644);
  32 MODULE_PARM_DESC(vbibufs, "number of vbi buffers, range 2-32");
  33
  34 static unsigned int vbi_debug;
  35 module_param(vbi_debug, int, 0644);
  36 MODULE_PARM_DESC(vbi_debug, "enable debug messages [vbi]");
  37
  38 #define dprintk(level, fmt, arg...)     if (vbi_debug >= level) \
  39         printk(KERN_DEBUG "%s: " fmt, dev->core->name , ## arg)
  40
  41 /* ------------------------------------------------------------------ */
  42
  43 static void
  44 free_buffer(struct videobuf_queue *vq, struct em28xx_buffer *buf)
  45 {
  46         struct em28xx_fh     *fh  = vq->priv_data;
  47         struct em28xx        *dev = fh->dev;
  48         unsigned long flags = 0;
  49         if (in_interrupt())
  50                 BUG();
  51
  52         /* We used to wait for the buffer to finish here, but this didn't work
  53            because, as we were keeping the state as VIDEOBUF_QUEUED,
  54            videobuf_queue_cancel marked it as finished for us.
  55            (Also, it could wedge forever if the hardware was misconfigured.)
  56
  57            This should be safe; by the time we get here, the buffer isn't
  58            queued anymore. If we ever start marking the buffers as
  59            VIDEOBUF_ACTIVE, it won't be, though.
  60         */
  61         spin_lock_irqsave(&dev->slock, flags);
  62         if (dev->isoc_ctl.vbi_buf == buf)
  63                 dev->isoc_ctl.vbi_buf = NULL;
  64         spin_unlock_irqrestore(&dev->slock, flags);
  65
  66         videobuf_vmalloc_free(&buf->vb);
  67         buf->vb.state = VIDEOBUF_NEEDS_INIT;
  68 }
  69
  70 static int
  71 vbi_setup(struct videobuf_queue *q, unsigned int *count, unsigned int *size)
  72 {
  73         struct em28xx_fh     *fh  = q->priv_data;
  74         struct em28xx        *dev = fh->dev;
  75
  76         *size = dev->vbi_width * dev->vbi_height * 2;
  77
  78         if (0 == *count)
  79                 *count = vbibufs;
  80         if (*count < 2)
  81                 *count = 2;
  82         if (*count > 32)
  83                 *count = 32;
  84         return 0;
  85 }
  86
  87 static int
  88 vbi_prepare(struct videobuf_queue *q, struct videobuf_buffer *vb,
  89             enum v4l2_field field)
  90 {
  91         struct em28xx_fh     *fh  = q->priv_data;
  92         struct em28xx        *dev = fh->dev;
  93         struct em28xx_buffer *buf = container_of(vb, struct em28xx_buffer, vb);
  94         int                  rc = 0;
  95
  96         buf->vb.size = dev->vbi_width * dev->vbi_height * 2;
  97
  98         if (0 != buf->vb.baddr  &&  buf->vb.bsize < buf->vb.size)
  99                 return -EINVAL;
 100
 101         buf->vb.width  = dev->vbi_width;
 102         buf->vb.height = dev->vbi_height;
 103         buf->vb.field  = field;
 104
 105         if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
 106                 rc = videobuf_iolock(q, &buf->vb, NULL);
 107                 if (rc < 0)
 108                         goto fail;
 109         }
 110
 111         buf->vb.state = VIDEOBUF_PREPARED;
 112         return 0;
 113
 114 fail:
 115         free_buffer(q, buf);
 116         return rc;
 117 }
 118
 119 static void
 120 vbi_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
 121 {
 122         struct em28xx_buffer    *buf     = container_of(vb,
 123                                                         struct em28xx_buffer,
 124                                                         vb);
 125         struct em28xx_fh        *fh      = vq->priv_data;
 126         struct em28xx           *dev     = fh->dev;
 127         struct em28xx_dmaqueue  *vbiq    = &dev->vbiq;
 128
 129         buf->vb.state = VIDEOBUF_QUEUED;
 130         list_add_tail(&buf->vb.queue, &vbiq->active);
 131 }
 132
 133 static void vbi_release(struct videobuf_queue *q, struct videobuf_buffer *vb)
 134 {
 135         struct em28xx_buffer *buf = container_of(vb, struct em28xx_buffer, vb);
 136         free_buffer(q, buf);
 137 }
 138
 139 struct videobuf_queue_ops em28xx_vbi_qops = {
 140         .buf_setup    = vbi_setup,
 141         .buf_prepare  = vbi_prepare,
 142         .buf_queue    = vbi_queue,
 143         .buf_release  = vbi_release,
 144 };