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 #include <linux/slab.h>
  28
  29 #include "em28xx.h"
  30
  31 static unsigned int vbibufs = 5;
  32 module_param(vbibufs, int, 0644);
  33 MODULE_PARM_DESC(vbibufs, "number of vbi buffers, range 2-32");
  34
  35 static unsigned int vbi_debug;
  36 module_param(vbi_debug, int, 0644);
  37 MODULE_PARM_DESC(vbi_debug, "enable debug messages [vbi]");
  38
  39 #define dprintk(level, fmt, arg...)     if (vbi_debug >= level) \
  40         printk(KERN_DEBUG "%s: " fmt, dev->core->name , ## arg)
  41
  42 /* ------------------------------------------------------------------ */
  43
  44 static void
  45 free_buffer(struct videobuf_queue *vq, struct em28xx_buffer *buf)
  46 {
  47         struct em28xx_fh     *fh  = vq->priv_data;
  48         struct em28xx        *dev = fh->dev;
  49         unsigned long flags = 0;
  50         if (in_interrupt())
  51                 BUG();
  52
  53         /* We used to wait for the buffer to finish here, but this didn't work
  54            because, as we were keeping the state as VIDEOBUF_QUEUED,
  55            videobuf_queue_cancel marked it as finished for us.
  56            (Also, it could wedge forever if the hardware was misconfigured.)
  57
  58            This should be safe; by the time we get here, the buffer isn't
  59            queued anymore. If we ever start marking the buffers as
  60            VIDEOBUF_ACTIVE, it won't be, though.
  61         */
  62         spin_lock_irqsave(&dev->slock, flags);
  63         if (dev->isoc_ctl.vbi_buf == buf)
  64                 dev->isoc_ctl.vbi_buf = NULL;
  65         spin_unlock_irqrestore(&dev->slock, flags);
  66
  67         videobuf_vmalloc_free(&buf->vb);
  68         buf->vb.state = VIDEOBUF_NEEDS_INIT;
  69 }
  70
  71 static int
  72 vbi_setup(struct videobuf_queue *q, unsigned int *count, unsigned int *size)
  73 {
  74         struct em28xx_fh     *fh  = q->priv_data;
  75         struct em28xx        *dev = fh->dev;
  76
  77         *size = dev->vbi_width * dev->vbi_height * 2;
  78
  79         if (0 == *count)
  80                 *count = vbibufs;
  81         if (*count < 2)
  82                 *count = 2;
  83         if (*count > 32)
  84                 *count = 32;
  85         return 0;
  86 }
  87
  88 static int
  89 vbi_prepare(struct videobuf_queue *q, struct videobuf_buffer *vb,
  90             enum v4l2_field field)
  91 {
  92         struct em28xx_fh     *fh  = q->priv_data;
  93         struct em28xx        *dev = fh->dev;
  94         struct em28xx_buffer *buf = container_of(vb, struct em28xx_buffer, vb);
  95         int                  rc = 0;
  96
  97         buf->vb.size = dev->vbi_width * dev->vbi_height * 2;
  98
  99         if (0 != buf->vb.baddr  &&  buf->vb.bsize < buf->vb.size)
 100                 return -EINVAL;
 101
 102         buf->vb.width  = dev->vbi_width;
 103         buf->vb.height = dev->vbi_height;
 104         buf->vb.field  = field;
 105
 106         if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
 107                 rc = videobuf_iolock(q, &buf->vb, NULL);
 108                 if (rc < 0)
 109                         goto fail;
 110         }
 111
 112         buf->vb.state = VIDEOBUF_PREPARED;
 113         return 0;
 114
 115 fail:
 116         free_buffer(q, buf);
 117         return rc;
 118 }
 119
 120 static void
 121 vbi_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
 122 {
 123         struct em28xx_buffer    *buf     = container_of(vb,
 124                                                         struct em28xx_buffer,
 125                                                         vb);
 126         struct em28xx_fh        *fh      = vq->priv_data;
 127         struct em28xx           *dev     = fh->dev;
 128         struct em28xx_dmaqueue  *vbiq    = &dev->vbiq;
 129
 130         buf->vb.state = VIDEOBUF_QUEUED;
 131         list_add_tail(&buf->vb.queue, &vbiq->active);
 132 }
 133
 134 static void vbi_release(struct videobuf_queue *q, struct videobuf_buffer *vb)
 135 {
 136         struct em28xx_buffer *buf = container_of(vb, struct em28xx_buffer, vb);
 137         free_buffer(q, buf);
 138 }
 139
 140 struct videobuf_queue_ops em28xx_vbi_qops = {
 141         .buf_setup    = vbi_setup,
 142         .buf_prepare  = vbi_prepare,
 143         .buf_queue    = vbi_queue,
 144         .buf_release  = vbi_release,
 145 };