drivers/media/usb/au0828/au0828-vbi.c

   1 /*
   2    au0828-vbi.c - VBI driver for au0828
   3
   4    Copyright (C) 2010 Devin Heitmueller <dheitmueller@kernellabs.com>
   5
   6    This work was sponsored by GetWellNetwork Inc.
   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 "au0828.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 /* ------------------------------------------------------------------ */
  36
  37 static void
  38 free_buffer(struct videobuf_queue *vq, struct au0828_buffer *buf)
  39 {
  40         struct au0828_fh     *fh  = vq->priv_data;
  41         struct au0828_dev    *dev = fh->dev;
  42         unsigned long flags = 0;
  43         if (in_interrupt())
  44                 BUG();
  45
  46         /* We used to wait for the buffer to finish here, but this didn't work
  47            because, as we were keeping the state as VIDEOBUF_QUEUED,
  48            videobuf_queue_cancel marked it as finished for us.
  49            (Also, it could wedge forever if the hardware was misconfigured.)
  50
  51            This should be safe; by the time we get here, the buffer isn't
  52            queued anymore. If we ever start marking the buffers as
  53            VIDEOBUF_ACTIVE, it won't be, though.
  54         */
  55         spin_lock_irqsave(&dev->slock, flags);
  56         if (dev->isoc_ctl.vbi_buf == buf)
  57                 dev->isoc_ctl.vbi_buf = NULL;
  58         spin_unlock_irqrestore(&dev->slock, flags);
  59
  60         videobuf_vmalloc_free(&buf->vb);
  61         buf->vb.state = VIDEOBUF_NEEDS_INIT;
  62 }
  63
  64 static int
  65 vbi_setup(struct videobuf_queue *q, unsigned int *count, unsigned int *size)
  66 {
  67         struct au0828_fh     *fh  = q->priv_data;
  68         struct au0828_dev    *dev = fh->dev;
  69
  70         *size = dev->vbi_width * dev->vbi_height * 2;
  71
  72         if (0 == *count)
  73                 *count = vbibufs;
  74         if (*count < 2)
  75                 *count = 2;
  76         if (*count > 32)
  77                 *count = 32;
  78         return 0;
  79 }
  80
  81 static int
  82 vbi_prepare(struct videobuf_queue *q, struct videobuf_buffer *vb,
  83             enum v4l2_field field)
  84 {
  85         struct au0828_fh     *fh  = q->priv_data;
  86         struct au0828_dev    *dev = fh->dev;
  87         struct au0828_buffer *buf = container_of(vb, struct au0828_buffer, vb);
  88         int                  rc = 0;
  89
  90         buf->vb.size = dev->vbi_width * dev->vbi_height * 2;
  91
  92         if (0 != buf->vb.baddr  &&  buf->vb.bsize < buf->vb.size)
  93                 return -EINVAL;
  94
  95         buf->vb.width  = dev->vbi_width;
  96         buf->vb.height = dev->vbi_height;
  97         buf->vb.field  = field;
  98
  99         if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
 100                 rc = videobuf_iolock(q, &buf->vb, NULL);
 101                 if (rc < 0)
 102                         goto fail;
 103         }
 104
 105         buf->vb.state = VIDEOBUF_PREPARED;
 106         return 0;
 107
 108 fail:
 109         free_buffer(q, buf);
 110         return rc;
 111 }
 112
 113 static void
 114 vbi_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
 115 {
 116         struct au0828_buffer    *buf     = container_of(vb,
 117                                                         struct au0828_buffer,
 118                                                         vb);
 119         struct au0828_fh        *fh      = vq->priv_data;
 120         struct au0828_dev       *dev     = fh->dev;
 121         struct au0828_dmaqueue  *vbiq    = &dev->vbiq;
 122
 123         buf->vb.state = VIDEOBUF_QUEUED;
 124         list_add_tail(&buf->vb.queue, &vbiq->active);
 125 }
 126
 127 static void vbi_release(struct videobuf_queue *q, struct videobuf_buffer *vb)
 128 {
 129         struct au0828_buffer *buf = container_of(vb, struct au0828_buffer, vb);
 130         free_buffer(q, buf);
 131 }
 132
 133 struct videobuf_queue_ops au0828_vbi_qops = {
 134         .buf_setup    = vbi_setup,
 135         .buf_prepare  = vbi_prepare,
 136         .buf_queue    = vbi_queue,
 137         .buf_release  = vbi_release,
 138 };