net: Fix thinko in backport of skb destructor fix.

[linux-2.6/mini2440.git] / drivers / media / video / cx18 / cx18-fileops.c

/*
 *  cx18 file operation functions
 *
 *  Derived from ivtv-fileops.c
 *
 *  Copyright (C) 2007  Hans Verkuil <hverkuil@xs4all.nl>
 *  Copyright (C) 2008  Andy Walls <awalls@radix.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 *  02111-1307  USA
 */

#include "cx18-driver.h"
#include "cx18-fileops.h"
#include "cx18-i2c.h"
#include "cx18-queue.h"
#include "cx18-vbi.h"
#include "cx18-audio.h"
#include "cx18-mailbox.h"
#include "cx18-scb.h"
#include "cx18-streams.h"
#include "cx18-controls.h"
#include "cx18-ioctl.h"
#include "cx18-cards.h"

/* This function tries to claim the stream for a specific file descriptor.
   If no one else is using this stream then the stream is claimed and
   associated VBI streams are also automatically claimed.
   Possible error returns: -EBUSY if someone else has claimed
   the stream or 0 on success. */
static int cx18_claim_stream(struct cx18_open_id *id, int type)
{
        struct cx18 *cx = id->cx;
        struct cx18_stream *s = &cx->streams[type];
        struct cx18_stream *s_vbi;
        int vbi_type;

        if (test_and_set_bit(CX18_F_S_CLAIMED, &s->s_flags)) {
                /* someone already claimed this stream */
                if (s->id == id->open_id) {
                        /* yes, this file descriptor did. So that's OK. */
                        return 0;
                }
                if (s->id == -1 && type == CX18_ENC_STREAM_TYPE_VBI) {
                        /* VBI is handled already internally, now also assign
                           the file descriptor to this stream for external
                           reading of the stream. */
                        s->id = id->open_id;
                        CX18_DEBUG_INFO("Start Read VBI\n");
                        return 0;
                }
                /* someone else is using this stream already */
                CX18_DEBUG_INFO("Stream %d is busy\n", type);
                return -EBUSY;
        }
        s->id = id->open_id;

        /* CX18_ENC_STREAM_TYPE_MPG needs to claim CX18_ENC_STREAM_TYPE_VBI
           (provided VBI insertion is on and sliced VBI is selected), for all
           other streams we're done */
        if (type == CX18_ENC_STREAM_TYPE_MPG &&
            cx->vbi.insert_mpeg && !cx18_raw_vbi(cx)) {
                vbi_type = CX18_ENC_STREAM_TYPE_VBI;
        } else {
                return 0;
        }
        s_vbi = &cx->streams[vbi_type];

        set_bit(CX18_F_S_CLAIMED, &s_vbi->s_flags);

        /* mark that it is used internally */
        set_bit(CX18_F_S_INTERNAL_USE, &s_vbi->s_flags);
        return 0;
}

/* This function releases a previously claimed stream. It will take into
   account associated VBI streams. */
static void cx18_release_stream(struct cx18_stream *s)
{
        struct cx18 *cx = s->cx;
        struct cx18_stream *s_vbi;

        s->id = -1;
        if (s->type == CX18_ENC_STREAM_TYPE_VBI &&
                test_bit(CX18_F_S_INTERNAL_USE, &s->s_flags)) {
                /* this stream is still in use internally */
                return;
        }
        if (!test_and_clear_bit(CX18_F_S_CLAIMED, &s->s_flags)) {
                CX18_DEBUG_WARN("Release stream %s not in use!\n", s->name);
                return;
        }

        cx18_flush_queues(s);

        /* CX18_ENC_STREAM_TYPE_MPG needs to release CX18_ENC_STREAM_TYPE_VBI,
           for all other streams we're done */
        if (s->type == CX18_ENC_STREAM_TYPE_MPG)
                s_vbi = &cx->streams[CX18_ENC_STREAM_TYPE_VBI];
        else
                return;

        /* clear internal use flag */
        if (!test_and_clear_bit(CX18_F_S_INTERNAL_USE, &s_vbi->s_flags)) {
                /* was already cleared */
                return;
        }
        if (s_vbi->id != -1) {
                /* VBI stream still claimed by a file descriptor */
                return;
        }
        clear_bit(CX18_F_S_CLAIMED, &s_vbi->s_flags);
        cx18_flush_queues(s_vbi);
}

static void cx18_dualwatch(struct cx18 *cx)
{
        struct v4l2_tuner vt;
        u32 new_bitmap;
        u32 new_stereo_mode;
        const u32 stereo_mask = 0x0300;
        const u32 dual = 0x0200;
        u32 h;

        new_stereo_mode = cx->params.audio_properties & stereo_mask;
        memset(&vt, 0, sizeof(vt));
        cx18_call_all(cx, tuner, g_tuner, &vt);
        if (vt.audmode == V4L2_TUNER_MODE_LANG1_LANG2 &&
                        (vt.rxsubchans & V4L2_TUNER_SUB_LANG2))
                new_stereo_mode = dual;

        if (new_stereo_mode == cx->dualwatch_stereo_mode)
                return;

        new_bitmap = new_stereo_mode
                        | (cx->params.audio_properties & ~stereo_mask);

        CX18_DEBUG_INFO("dualwatch: change stereo flag from 0x%x to 0x%x. "
                        "new audio_bitmask=0x%ux\n",
                        cx->dualwatch_stereo_mode, new_stereo_mode, new_bitmap);

        h = cx18_find_handle(cx);
        if (h == CX18_INVALID_TASK_HANDLE) {
                CX18_DEBUG_INFO("dualwatch: can't find valid task handle\n");
                return;
        }

        if (cx18_vapi(cx,
                      CX18_CPU_SET_AUDIO_PARAMETERS, 2, h, new_bitmap) == 0) {
                cx->dualwatch_stereo_mode = new_stereo_mode;
                return;
        }
        CX18_DEBUG_INFO("dualwatch: changing stereo flag failed\n");
}


static struct cx18_buffer *cx18_get_buffer(struct cx18_stream *s, int non_block, int *err)
{
        struct cx18 *cx = s->cx;
        struct cx18_stream *s_vbi = &cx->streams[CX18_ENC_STREAM_TYPE_VBI];
        struct cx18_buffer *buf;
        DEFINE_WAIT(wait);

        *err = 0;
        while (1) {
                if (s->type == CX18_ENC_STREAM_TYPE_MPG) {
                        /* Process pending program info updates and pending
                           VBI data */

                        if (time_after(jiffies, cx->dualwatch_jiffies + msecs_to_jiffies(1000))) {
                                cx->dualwatch_jiffies = jiffies;
                                cx18_dualwatch(cx);
                        }
                        if (test_bit(CX18_F_S_INTERNAL_USE, &s_vbi->s_flags) &&
                            !test_bit(CX18_F_S_APPL_IO, &s_vbi->s_flags)) {
                                while ((buf = cx18_dequeue(s_vbi, &s_vbi->q_full))) {
                                        /* byteswap and process VBI data */
                                        cx18_process_vbi_data(cx, buf,
                                                              s_vbi->type);
                                        cx18_stream_put_buf_fw(s_vbi, buf);
                                }
                        }
                        buf = &cx->vbi.sliced_mpeg_buf;
                        if (buf->readpos != buf->bytesused)
                                return buf;
                }

                /* do we have new data? */
                buf = cx18_dequeue(s, &s->q_full);
                if (buf) {
                        if (!test_and_clear_bit(CX18_F_B_NEED_BUF_SWAP,
                                                &buf->b_flags))
                                return buf;
                        if (s->type == CX18_ENC_STREAM_TYPE_MPG)
                                /* byteswap MPG data */
                                cx18_buf_swap(buf);
                        else {
                                /* byteswap and process VBI data */
                                cx18_process_vbi_data(cx, buf, s->type);
                        }
                        return buf;
                }

                /* return if end of stream */
                if (!test_bit(CX18_F_S_STREAMING, &s->s_flags)) {
                        CX18_DEBUG_INFO("EOS %s\n", s->name);
                        return NULL;
                }

                /* return if file was opened with O_NONBLOCK */
                if (non_block) {
                        *err = -EAGAIN;
                        return NULL;
                }

                /* wait for more data to arrive */
                prepare_to_wait(&s->waitq, &wait, TASK_INTERRUPTIBLE);
                /* New buffers might have become available before we were added
                   to the waitqueue */
                if (!atomic_read(&s->q_full.buffers))
                        schedule();
                finish_wait(&s->waitq, &wait);
                if (signal_pending(current)) {
                        /* return if a signal was received */
                        CX18_DEBUG_INFO("User stopped %s\n", s->name);
                        *err = -EINTR;
                        return NULL;
                }
        }
}

static void cx18_setup_sliced_vbi_buf(struct cx18 *cx)
{
        int idx = cx->vbi.inserted_frame % CX18_VBI_FRAMES;

        cx->vbi.sliced_mpeg_buf.buf = cx->vbi.sliced_mpeg_data[idx];
        cx->vbi.sliced_mpeg_buf.bytesused = cx->vbi.sliced_mpeg_size[idx];
        cx->vbi.sliced_mpeg_buf.readpos = 0;
}

static size_t cx18_copy_buf_to_user(struct cx18_stream *s,
                struct cx18_buffer *buf, char __user *ubuf, size_t ucount)
{
        struct cx18 *cx = s->cx;
        size_t len = buf->bytesused - buf->readpos;

        if (len > ucount)
                len = ucount;
        if (cx->vbi.insert_mpeg && s->type == CX18_ENC_STREAM_TYPE_MPG &&
            !cx18_raw_vbi(cx) && buf != &cx->vbi.sliced_mpeg_buf) {
                /*
                 * Try to find a good splice point in the PS, just before
                 * an MPEG-2 Program Pack start code, and provide only
                 * up to that point to the user, so it's easy to insert VBI data
                 * the next time around.
                 */
                /* FIXME - This only works for an MPEG-2 PS, not a TS */
                /*
                 * An MPEG-2 Program Stream (PS) is a series of
                 * MPEG-2 Program Packs terminated by an
                 * MPEG Program End Code after the last Program Pack.
                 * A Program Pack may hold a PS System Header packet and any
                 * number of Program Elementary Stream (PES) Packets
                 */
                const char *start = buf->buf + buf->readpos;
                const char *p = start + 1;
                const u8 *q;
                u8 ch = cx->search_pack_header ? 0xba : 0xe0;
                int stuffing, i;

                while (start + len > p) {
                        /* Scan for a 0 to find a potential MPEG-2 start code */
                        q = memchr(p, 0, start + len - p);
                        if (q == NULL)
                                break;
                        p = q + 1;
                        /*
                         * Keep looking if not a
                         * MPEG-2 Pack header start code:  0x00 0x00 0x01 0xba
                         * or MPEG-2 video PES start code: 0x00 0x00 0x01 0xe0
                         */
                        if ((char *)q + 15 >= buf->buf + buf->bytesused ||
                            q[1] != 0 || q[2] != 1 || q[3] != ch)
                                continue;

                        /* If expecting the primary video PES */
                        if (!cx->search_pack_header) {
                                /* Continue if it couldn't be a PES packet */
                                if ((q[6] & 0xc0) != 0x80)
                                        continue;
                                /* Check if a PTS or PTS & DTS follow */
                                if (((q[7] & 0xc0) == 0x80 &&  /* PTS only */
                                     (q[9] & 0xf0) == 0x20) || /* PTS only */
                                    ((q[7] & 0xc0) == 0xc0 &&  /* PTS & DTS */
                                     (q[9] & 0xf0) == 0x30)) { /* DTS follows */
                                        /* Assume we found the video PES hdr */
                                        ch = 0xba; /* next want a Program Pack*/
                                        cx->search_pack_header = 1;
                                        p = q + 9; /* Skip this video PES hdr */
                                }
                                continue;
                        }

                        /* We may have found a Program Pack start code */

                        /* Get the count of stuffing bytes & verify them */
                        stuffing = q[13] & 7;
                        /* all stuffing bytes must be 0xff */
                        for (i = 0; i < stuffing; i++)
                                if (q[14 + i] != 0xff)
                                        break;
                        if (i == stuffing && /* right number of stuffing bytes*/
                            (q[4] & 0xc4) == 0x44 && /* marker check */
                            (q[12] & 3) == 3 &&  /* marker check */
                            q[14 + stuffing] == 0 && /* PES Pack or Sys Hdr */
                            q[15 + stuffing] == 0 &&
                            q[16 + stuffing] == 1) {
                                /* We declare we actually found a Program Pack*/
                                cx->search_pack_header = 0; /* expect vid PES */
                                len = (char *)q - start;
                                cx18_setup_sliced_vbi_buf(cx);
                                break;
                        }
                }
        }
        if (copy_to_user(ubuf, (u8 *)buf->buf + buf->readpos, len)) {
                CX18_DEBUG_WARN("copy %zd bytes to user failed for %s\n",
                                len, s->name);
                return -EFAULT;
        }
        buf->readpos += len;
        if (s->type == CX18_ENC_STREAM_TYPE_MPG &&
            buf != &cx->vbi.sliced_mpeg_buf)
                cx->mpg_data_received += len;
        return len;
}

static ssize_t cx18_read(struct cx18_stream *s, char __user *ubuf,
                size_t tot_count, int non_block)
{
        struct cx18 *cx = s->cx;
        size_t tot_written = 0;
        int single_frame = 0;

        if (atomic_read(&cx->ana_capturing) == 0 && s->id == -1) {
                /* shouldn't happen */
                CX18_DEBUG_WARN("Stream %s not initialized before read\n",
                                s->name);
                return -EIO;
        }

        /* Each VBI buffer is one frame, the v4l2 API says that for VBI the
           frames should arrive one-by-one, so make sure we never output more
           than one VBI frame at a time */
        if (s->type == CX18_ENC_STREAM_TYPE_VBI && !cx18_raw_vbi(cx))
                single_frame = 1;

        for (;;) {
                struct cx18_buffer *buf;
                int rc;

                buf = cx18_get_buffer(s, non_block, &rc);
                /* if there is no data available... */
                if (buf == NULL) {
                        /* if we got data, then return that regardless */
                        if (tot_written)
                                break;
                        /* EOS condition */
                        if (rc == 0) {
                                clear_bit(CX18_F_S_STREAMOFF, &s->s_flags);
                                clear_bit(CX18_F_S_APPL_IO, &s->s_flags);
                                cx18_release_stream(s);
                        }
                        /* set errno */
                        return rc;
                }

                rc = cx18_copy_buf_to_user(s, buf, ubuf + tot_written,
                                tot_count - tot_written);

                if (buf != &cx->vbi.sliced_mpeg_buf) {
                        if (buf->readpos == buf->bytesused)
                                cx18_stream_put_buf_fw(s, buf);
                        else
                                cx18_push(s, buf, &s->q_full);
                } else if (buf->readpos == buf->bytesused) {
                        int idx = cx->vbi.inserted_frame % CX18_VBI_FRAMES;

                        cx->vbi.sliced_mpeg_size[idx] = 0;
                        cx->vbi.inserted_frame++;
                        cx->vbi_data_inserted += buf->bytesused;
                }
                if (rc < 0)
                        return rc;
                tot_written += rc;

                if (tot_written == tot_count || single_frame)
                        break;
        }
        return tot_written;
}

static ssize_t cx18_read_pos(struct cx18_stream *s, char __user *ubuf,
                size_t count, loff_t *pos, int non_block)
{
        ssize_t rc = count ? cx18_read(s, ubuf, count, non_block) : 0;
        struct cx18 *cx = s->cx;

        CX18_DEBUG_HI_FILE("read %zd from %s, got %zd\n", count, s->name, rc);
        if (rc > 0)
                pos += rc;
        return rc;
}

int cx18_start_capture(struct cx18_open_id *id)
{
        struct cx18 *cx = id->cx;
        struct cx18_stream *s = &cx->streams[id->type];
        struct cx18_stream *s_vbi;

        if (s->type == CX18_ENC_STREAM_TYPE_RAD) {
                /* you cannot read from these stream types. */
                return -EPERM;
        }

        /* Try to claim this stream. */
        if (cx18_claim_stream(id, s->type))
                return -EBUSY;

        /* If capture is already in progress, then we also have to
           do nothing extra. */
        if (test_bit(CX18_F_S_STREAMOFF, &s->s_flags) ||
            test_and_set_bit(CX18_F_S_STREAMING, &s->s_flags)) {
                set_bit(CX18_F_S_APPL_IO, &s->s_flags);
                return 0;
        }

        /* Start VBI capture if required */
        s_vbi = &cx->streams[CX18_ENC_STREAM_TYPE_VBI];
        if (s->type == CX18_ENC_STREAM_TYPE_MPG &&
            test_bit(CX18_F_S_INTERNAL_USE, &s_vbi->s_flags) &&
            !test_and_set_bit(CX18_F_S_STREAMING, &s_vbi->s_flags)) {
                /* Note: the CX18_ENC_STREAM_TYPE_VBI is claimed
                   automatically when the MPG stream is claimed.
                   We only need to start the VBI capturing. */
                if (cx18_start_v4l2_encode_stream(s_vbi)) {
                        CX18_DEBUG_WARN("VBI capture start failed\n");

                        /* Failure, clean up and return an error */
                        clear_bit(CX18_F_S_STREAMING, &s_vbi->s_flags);
                        clear_bit(CX18_F_S_STREAMING, &s->s_flags);
                        /* also releases the associated VBI stream */
                        cx18_release_stream(s);
                        return -EIO;
                }
                CX18_DEBUG_INFO("VBI insertion started\n");
        }

        /* Tell the card to start capturing */
        if (!cx18_start_v4l2_encode_stream(s)) {
                /* We're done */
                set_bit(CX18_F_S_APPL_IO, &s->s_flags);
                /* Resume a possibly paused encoder */
                if (test_and_clear_bit(CX18_F_I_ENC_PAUSED, &cx->i_flags))
                        cx18_vapi(cx, CX18_CPU_CAPTURE_PAUSE, 1, s->handle);
                return 0;
        }

        /* failure, clean up */
        CX18_DEBUG_WARN("Failed to start capturing for stream %s\n", s->name);

        /* Note: the CX18_ENC_STREAM_TYPE_VBI is released
           automatically when the MPG stream is released.
           We only need to stop the VBI capturing. */
        if (s->type == CX18_ENC_STREAM_TYPE_MPG &&
            test_bit(CX18_F_S_STREAMING, &s_vbi->s_flags)) {
                cx18_stop_v4l2_encode_stream(s_vbi, 0);
                clear_bit(CX18_F_S_STREAMING, &s_vbi->s_flags);
        }
        clear_bit(CX18_F_S_STREAMING, &s->s_flags);
        cx18_release_stream(s);
        return -EIO;
}

ssize_t cx18_v4l2_read(struct file *filp, char __user *buf, size_t count,
                loff_t *pos)
{
        struct cx18_open_id *id = filp->private_data;
        struct cx18 *cx = id->cx;
        struct cx18_stream *s = &cx->streams[id->type];
        int rc;

        CX18_DEBUG_HI_FILE("read %zd bytes from %s\n", count, s->name);

        mutex_lock(&cx->serialize_lock);
        rc = cx18_start_capture(id);
        mutex_unlock(&cx->serialize_lock);
        if (rc)
                return rc;
        return cx18_read_pos(s, buf, count, pos, filp->f_flags & O_NONBLOCK);
}

unsigned int cx18_v4l2_enc_poll(struct file *filp, poll_table *wait)
{
        struct cx18_open_id *id = filp->private_data;
        struct cx18 *cx = id->cx;
        struct cx18_stream *s = &cx->streams[id->type];
        int eof = test_bit(CX18_F_S_STREAMOFF, &s->s_flags);

        /* Start a capture if there is none */
        if (!eof && !test_bit(CX18_F_S_STREAMING, &s->s_flags)) {
                int rc;

                mutex_lock(&cx->serialize_lock);
                rc = cx18_start_capture(id);
                mutex_unlock(&cx->serialize_lock);
                if (rc) {
                        CX18_DEBUG_INFO("Could not start capture for %s (%d)\n",
                                        s->name, rc);
                        return POLLERR;
                }
                CX18_DEBUG_FILE("Encoder poll started capture\n");
        }

        /* add stream's waitq to the poll list */
        CX18_DEBUG_HI_FILE("Encoder poll\n");
        poll_wait(filp, &s->waitq, wait);

        if (atomic_read(&s->q_full.buffers))
                return POLLIN | POLLRDNORM;
        if (eof)
                return POLLHUP;
        return 0;
}

void cx18_stop_capture(struct cx18_open_id *id, int gop_end)
{
        struct cx18 *cx = id->cx;
        struct cx18_stream *s = &cx->streams[id->type];

        CX18_DEBUG_IOCTL("close() of %s\n", s->name);

        /* 'Unclaim' this stream */

        /* Stop capturing */
        if (test_bit(CX18_F_S_STREAMING, &s->s_flags)) {
                struct cx18_stream *s_vbi =
                        &cx->streams[CX18_ENC_STREAM_TYPE_VBI];

                CX18_DEBUG_INFO("close stopping capture\n");
                /* Special case: a running VBI capture for VBI insertion
                   in the mpeg stream. Need to stop that too. */
                if (id->type == CX18_ENC_STREAM_TYPE_MPG &&
                    test_bit(CX18_F_S_STREAMING, &s_vbi->s_flags) &&
                    !test_bit(CX18_F_S_APPL_IO, &s_vbi->s_flags)) {
                        CX18_DEBUG_INFO("close stopping embedded VBI capture\n");
                        cx18_stop_v4l2_encode_stream(s_vbi, 0);
                }
                if (id->type == CX18_ENC_STREAM_TYPE_VBI &&
                    test_bit(CX18_F_S_INTERNAL_USE, &s->s_flags))
                        /* Also used internally, don't stop capturing */
                        s->id = -1;
                else
                        cx18_stop_v4l2_encode_stream(s, gop_end);
        }
        if (!gop_end) {
                clear_bit(CX18_F_S_APPL_IO, &s->s_flags);
                clear_bit(CX18_F_S_STREAMOFF, &s->s_flags);
                cx18_release_stream(s);
        }
}

int cx18_v4l2_close(struct file *filp)
{
        struct cx18_open_id *id = filp->private_data;
        struct cx18 *cx = id->cx;
        struct cx18_stream *s = &cx->streams[id->type];

        CX18_DEBUG_IOCTL("close() of %s\n", s->name);

        v4l2_prio_close(&cx->prio, &id->prio);

        /* Easy case first: this stream was never claimed by us */
        if (s->id != id->open_id) {
                kfree(id);
                return 0;
        }

        /* 'Unclaim' this stream */

        /* Stop radio */
        mutex_lock(&cx->serialize_lock);
        if (id->type == CX18_ENC_STREAM_TYPE_RAD) {
                /* Closing radio device, return to TV mode */
                cx18_mute(cx);
                /* Mark that the radio is no longer in use */
                clear_bit(CX18_F_I_RADIO_USER, &cx->i_flags);
                /* Switch tuner to TV */
                cx18_call_all(cx, core, s_std, cx->std);
                /* Select correct audio input (i.e. TV tuner or Line in) */
                cx18_audio_set_io(cx);
                if (atomic_read(&cx->ana_capturing) > 0) {
                        /* Undo video mute */
                        cx18_vapi(cx, CX18_CPU_SET_VIDEO_MUTE, 2, s->handle,
                                cx->params.video_mute |
                                        (cx->params.video_mute_yuv << 8));
                }
                /* Done! Unmute and continue. */
                cx18_unmute(cx);
                cx18_release_stream(s);
        } else {
                cx18_stop_capture(id, 0);
        }
        kfree(id);
        mutex_unlock(&cx->serialize_lock);
        return 0;
}

static int cx18_serialized_open(struct cx18_stream *s, struct file *filp)
{
        struct cx18 *cx = s->cx;
        struct cx18_open_id *item;

        CX18_DEBUG_FILE("open %s\n", s->name);

        /* Allocate memory */
        item = kmalloc(sizeof(struct cx18_open_id), GFP_KERNEL);
        if (NULL == item) {
                CX18_DEBUG_WARN("nomem on v4l2 open\n");
                return -ENOMEM;
        }
        item->cx = cx;
        item->type = s->type;
        v4l2_prio_open(&cx->prio, &item->prio);

        item->open_id = cx->open_id++;
        filp->private_data = item;

        if (item->type == CX18_ENC_STREAM_TYPE_RAD) {
                /* Try to claim this stream */
                if (cx18_claim_stream(item, item->type)) {
                        /* No, it's already in use */
                        kfree(item);
                        return -EBUSY;
                }

                if (!test_bit(CX18_F_I_RADIO_USER, &cx->i_flags)) {
                        if (atomic_read(&cx->ana_capturing) > 0) {
                                /* switching to radio while capture is
                                   in progress is not polite */
                                cx18_release_stream(s);
                                kfree(item);
                                return -EBUSY;
                        }
                }

                /* Mark that the radio is being used. */
                set_bit(CX18_F_I_RADIO_USER, &cx->i_flags);
                /* We have the radio */
                cx18_mute(cx);
                /* Switch tuner to radio */
                cx18_call_all(cx, tuner, s_radio);
                /* Select the correct audio input (i.e. radio tuner) */
                cx18_audio_set_io(cx);
                /* Done! Unmute and continue. */
                cx18_unmute(cx);
        }
        return 0;
}

int cx18_v4l2_open(struct file *filp)
{
        int res;
        struct video_device *video_dev = video_devdata(filp);
        struct cx18_stream *s = video_get_drvdata(video_dev);
        struct cx18 *cx = s->cx;;

        mutex_lock(&cx->serialize_lock);
        if (cx18_init_on_first_open(cx)) {
                CX18_ERR("Failed to initialize on minor %d\n",
                         video_dev->minor);
                mutex_unlock(&cx->serialize_lock);
                return -ENXIO;
        }
        res = cx18_serialized_open(s, filp);
        mutex_unlock(&cx->serialize_lock);
        return res;
}

void cx18_mute(struct cx18 *cx)
{
        u32 h;
        if (atomic_read(&cx->ana_capturing)) {
                h = cx18_find_handle(cx);
                if (h != CX18_INVALID_TASK_HANDLE)
                        cx18_vapi(cx, CX18_CPU_SET_AUDIO_MUTE, 2, h, 1);
                else
                        CX18_ERR("Can't find valid task handle for mute\n");
        }
        CX18_DEBUG_INFO("Mute\n");
}

void cx18_unmute(struct cx18 *cx)
{
        u32 h;
        if (atomic_read(&cx->ana_capturing)) {
                h = cx18_find_handle(cx);
                if (h != CX18_INVALID_TASK_HANDLE) {
                        cx18_msleep_timeout(100, 0);
                        cx18_vapi(cx, CX18_CPU_SET_MISC_PARAMETERS, 2, h, 12);
                        cx18_vapi(cx, CX18_CPU_SET_AUDIO_MUTE, 2, h, 0);
                } else
                        CX18_ERR("Can't find valid task handle for unmute\n");
        }
        CX18_DEBUG_INFO("Unmute\n");
}