cx18-fileops.c

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/*
 *  cx18 file operation functions
 *
 *  Derived from ivtv-fileops.c
 *
 *  Copyright (C) 2007  Hans Verkuil <[email protected]>
 *  Copyright (C) 2008  Andy Walls <[email protected]>
 *
 *  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 and IDX streams are also automatically claimed.
   Possible error returns: -EBUSY if someone else has claimed
   the stream or 0 on success. */
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_assoc;

    /* Nothing should ever try to directly claim the IDX stream */
    if (type == CX18_ENC_STREAM_TYPE_IDX) {
        CX18_WARN("MPEG Index stream cannot be claimed "
              "directly, but something tried.\n");
        return -EINVAL;
    }

    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, if VBI insertion is on for sliced VBI, or
     * CX18_ENC_STREAM_TYPE_IDX, if VBI insertion is off for sliced VBI
     * (We don't yet fix up MPEG Index entries for our inserted packets).
     *
     * For all other streams we're done.
     */
    if (type != CX18_ENC_STREAM_TYPE_MPG)
        return 0;

    s_assoc = &cx->streams[CX18_ENC_STREAM_TYPE_IDX];
    if (cx->vbi.insert_mpeg && !cx18_raw_vbi(cx))
        s_assoc = &cx->streams[CX18_ENC_STREAM_TYPE_VBI];
    else if (!cx18_stream_enabled(s_assoc))
        return 0;

    set_bit(CX18_F_S_CLAIMED, &s_assoc->s_flags);

    /* mark that it is used internally */
    set_bit(CX18_F_S_INTERNAL_USE, &s_assoc->s_flags);
    return 0;
}
EXPORT_SYMBOL(cx18_claim_stream);

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

    s->id = -1;
    if (s->type == CX18_ENC_STREAM_TYPE_IDX) {
        /*
         * The IDX stream is only used internally, and can
         * only be indirectly unclaimed by unclaiming the MPG stream.
         */
        return;
    }

    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 the
     * CX18_ENC_STREAM_TYPE_VBI and/or CX18_ENC_STREAM_TYPE_IDX streams.
     *
     * For all other streams we're done.
     */
    if (s->type != CX18_ENC_STREAM_TYPE_MPG)
        return;

    /* Unclaim the associated MPEG Index stream */
    s_assoc = &cx->streams[CX18_ENC_STREAM_TYPE_IDX];
    if (test_and_clear_bit(CX18_F_S_INTERNAL_USE, &s_assoc->s_flags)) {
        clear_bit(CX18_F_S_CLAIMED, &s_assoc->s_flags);
        cx18_flush_queues(s_assoc);
    }

    /* Unclaim the associated VBI stream */
    s_assoc = &cx->streams[CX18_ENC_STREAM_TYPE_VBI];
    if (test_and_clear_bit(CX18_F_S_INTERNAL_USE, &s_assoc->s_flags)) {
        if (s_assoc->id == -1) {
            /*
             * The VBI stream is not still claimed by a file
             * descriptor, so completely unclaim it.
             */
            clear_bit(CX18_F_S_CLAIMED, &s_assoc->s_flags);
            cx18_flush_queues(s_assoc);
        }
    }
}
EXPORT_SYMBOL(cx18_release_stream);

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

    new_stereo_mode = v4l2_ctrl_g_ctrl(cx->cxhdl.audio_mode);
    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;

    CX18_DEBUG_INFO("dualwatch: change stereo flag from 0x%x to 0x%x.\n",
               cx->dualwatch_stereo_mode, new_stereo_mode);
    if (v4l2_ctrl_s_ctrl(cx->cxhdl.audio_mode, new_stereo_mode))
        CX18_DEBUG_INFO("dualwatch: changing stereo flag failed\n");
}


static struct cx18_mdl *cx18_get_mdl(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_mdl *mdl;
    DEFINE_WAIT(wait);

    *err = 0;
    while (1) {
        if (s->type == CX18_ENC_STREAM_TYPE_MPG) {
            /* Process pending program updates and 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 ((mdl = cx18_dequeue(s_vbi,
                               &s_vbi->q_full))) {
                    /* byteswap and process VBI data */
                    cx18_process_vbi_data(cx, mdl,
                                  s_vbi->type);
                    cx18_stream_put_mdl_fw(s_vbi, mdl);
                }
            }
            mdl = &cx->vbi.sliced_mpeg_mdl;
            if (mdl->readpos != mdl->bytesused)
                return mdl;
        }

        /* do we have new data? */
        mdl = cx18_dequeue(s, &s->q_full);
        if (mdl) {
            if (!test_and_clear_bit(CX18_F_M_NEED_SWAP,
                        &mdl->m_flags))
                return mdl;
            if (s->type == CX18_ENC_STREAM_TYPE_MPG)
                /* byteswap MPG data */
                cx18_mdl_swap(mdl);
            else {
                /* byteswap and process VBI data */
                cx18_process_vbi_data(cx, mdl, s->type);
            }
            return mdl;
        }

        /* 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.depth))
            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_mdl(struct cx18 *cx)
{
    struct cx18_mdl *mdl = &cx->vbi.sliced_mpeg_mdl;
    struct cx18_buffer *buf = &cx->vbi.sliced_mpeg_buf;
    int idx = cx->vbi.inserted_frame % CX18_VBI_FRAMES;

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

    mdl->curr_buf = NULL;
    mdl->bytesused = cx->vbi.sliced_mpeg_size[idx];
    mdl->readpos = 0;
}

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

    *stop = false;
    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.
         *
         * This will not work for an MPEG-2 TS and has only been
         * verified by analysis to work for an MPEG-2 PS.  Helen Buus
         * pointed out this works for the CX23416 MPEG-2 DVD compatible
         * stream, and research indicates both the MPEG 2 SVCD and DVD
         * stream types use an MPEG-2 PS container.
         */
        /*
         * 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_mdl(cx);
                *stop = true;
                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 size_t cx18_copy_mdl_to_user(struct cx18_stream *s,
        struct cx18_mdl *mdl, char __user *ubuf, size_t ucount)
{
    size_t tot_written = 0;
    int rc;
    bool stop = false;

    if (mdl->curr_buf == NULL)
        mdl->curr_buf = list_first_entry(&mdl->buf_list,
                         struct cx18_buffer, list);

    if (list_entry_is_past_end(mdl->curr_buf, &mdl->buf_list, list)) {
        /*
         * For some reason we've exhausted the buffers, but the MDL
         * object still said some data was unread.
         * Fix that and bail out.
         */
        mdl->readpos = mdl->bytesused;
        return 0;
    }

    list_for_each_entry_from(mdl->curr_buf, &mdl->buf_list, list) {

        if (mdl->curr_buf->readpos >= mdl->curr_buf->bytesused)
            continue;

        rc = cx18_copy_buf_to_user(s, mdl->curr_buf, ubuf + tot_written,
                       ucount - tot_written, &stop);
        if (rc < 0)
            return rc;
        mdl->readpos += rc;
        tot_written += rc;

        if (stop || /* Forced stopping point for VBI insertion */
            tot_written >= ucount ||    /* Reader request statisfied */
            mdl->curr_buf->readpos < mdl->curr_buf->bytesused ||
            mdl->readpos >= mdl->bytesused) /* MDL buffers drained */
            break;
    }
    return tot_written;
}

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_mdl *mdl;
        int rc;

        mdl = cx18_get_mdl(s, non_block, &rc);
        /* if there is no data available... */
        if (mdl == 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_mdl_to_user(s, mdl, ubuf + tot_written,
                tot_count - tot_written);

        if (mdl != &cx->vbi.sliced_mpeg_mdl) {
            if (mdl->readpos == mdl->bytesused)
                cx18_stream_put_mdl_fw(s, mdl);
            else
                cx18_push(s, mdl, &s->q_full);
        } else if (mdl->readpos == mdl->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 += mdl->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;
    struct cx18_stream *s_idx;

    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 associated VBI or IDX stream capture if required */
    s_vbi = &cx->streams[CX18_ENC_STREAM_TYPE_VBI];
    s_idx = &cx->streams[CX18_ENC_STREAM_TYPE_IDX];
    if (s->type == CX18_ENC_STREAM_TYPE_MPG) {
        /*
         * The VBI and IDX streams should have been claimed
         * automatically, if for internal use, when the MPG stream was
         * claimed.  We only need to start these streams capturing.
         */
        if (test_bit(CX18_F_S_INTERNAL_USE, &s_idx->s_flags) &&
            !test_and_set_bit(CX18_F_S_STREAMING, &s_idx->s_flags)) {
            if (cx18_start_v4l2_encode_stream(s_idx)) {
                CX18_DEBUG_WARN("IDX capture start failed\n");
                clear_bit(CX18_F_S_STREAMING, &s_idx->s_flags);
                goto start_failed;
            }
            CX18_DEBUG_INFO("IDX capture started\n");
        }
        if (test_bit(CX18_F_S_INTERNAL_USE, &s_vbi->s_flags) &&
            !test_and_set_bit(CX18_F_S_STREAMING, &s_vbi->s_flags)) {
            if (cx18_start_v4l2_encode_stream(s_vbi)) {
                CX18_DEBUG_WARN("VBI capture start failed\n");
                clear_bit(CX18_F_S_STREAMING, &s_vbi->s_flags);
                goto start_failed;
            }
            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;
    }

start_failed:
    CX18_DEBUG_WARN("Failed to start capturing for stream %s\n", s->name);

    /*
     * The associated VBI and IDX streams for internal use are released
     * automatically when the MPG stream is released.  We only need to stop
     * the associated stream.
     */
    if (s->type == CX18_ENC_STREAM_TYPE_MPG) {
        /* Stop the IDX stream which is always for internal use */
        if (test_bit(CX18_F_S_STREAMING, &s_idx->s_flags)) {
            cx18_stop_v4l2_encode_stream(s_idx, 0);
            clear_bit(CX18_F_S_STREAMING, &s_idx->s_flags);
        }
        /* Stop the VBI stream, if only running for internal use */
        if (test_bit(CX18_F_S_STREAMING, &s_vbi->s_flags) &&
            !test_bit(CX18_F_S_APPL_IO, &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); /* Also releases associated streams */
    return -EIO;
}

ssize_t cx18_v4l2_read(struct file *filp, char __user *buf, size_t count,
        loff_t *pos)
{
    struct cx18_open_id *id = file2id(filp);
    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;

    if ((s->vb_type == V4L2_BUF_TYPE_VIDEO_CAPTURE) &&
        (id->type == CX18_ENC_STREAM_TYPE_YUV)) {
        return videobuf_read_stream(&s->vbuf_q, buf, count, pos, 0,
            filp->f_flags & O_NONBLOCK);
    }

    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 = file2id(filp);
    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");
    }

    if ((s->vb_type == V4L2_BUF_TYPE_VIDEO_CAPTURE) &&
        (id->type == CX18_ENC_STREAM_TYPE_YUV)) {
        int videobuf_poll = videobuf_poll_stream(filp, &s->vbuf_q, wait);
                if (eof && videobuf_poll == POLLERR)
                        return POLLHUP;
                else
                        return videobuf_poll;
    }

    /* 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.depth))
        return POLLIN | POLLRDNORM;
    if (eof)
        return POLLHUP;
    return 0;
}

int cx18_v4l2_mmap(struct file *file, struct vm_area_struct *vma)
{
    struct cx18_open_id *id = file->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);

    if ((s->vb_type == V4L2_BUF_TYPE_VIDEO_CAPTURE) &&
        (id->type == CX18_ENC_STREAM_TYPE_YUV)) {

        /* 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 -EINVAL;
            }
            CX18_DEBUG_FILE("Encoder mmap started capture\n");
        }

        return videobuf_mmap_mapper(&s->vbuf_q, vma);
    }

    return -EINVAL;
}

void cx18_vb_timeout(unsigned long data)
{
    struct cx18_stream *s = (struct cx18_stream *)data;
    struct cx18_videobuf_buffer *buf;
    unsigned long flags;

    /* Return all of the buffers in error state, so the vbi/vid inode
     * can return from blocking.
     */
    spin_lock_irqsave(&s->vb_lock, flags);
    while (!list_empty(&s->vb_capture)) {
        buf = list_entry(s->vb_capture.next,
            struct cx18_videobuf_buffer, vb.queue);
        list_del(&buf->vb.queue);
        buf->vb.state = VIDEOBUF_ERROR;
        wake_up(&buf->vb.done);
    }
    spin_unlock_irqrestore(&s->vb_lock, flags);
}

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];
    struct cx18_stream *s_vbi = &cx->streams[CX18_ENC_STREAM_TYPE_VBI];
    struct cx18_stream *s_idx = &cx->streams[CX18_ENC_STREAM_TYPE_IDX];

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

    /* 'Unclaim' this stream */

    /* Stop capturing */
    if (test_bit(CX18_F_S_STREAMING, &s->s_flags)) {
        CX18_DEBUG_INFO("close stopping capture\n");
        if (id->type == CX18_ENC_STREAM_TYPE_MPG) {
            /* Stop internal use associated VBI and IDX streams */
            if (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 (test_bit(CX18_F_S_STREAMING, &s_idx->s_flags)) {
                CX18_DEBUG_INFO("close stopping IDX capture\n");
                cx18_stop_v4l2_encode_stream(s_idx, 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 v4l2_fh *fh = filp->private_data;
    struct cx18_open_id *id = fh2id(fh);
    struct cx18 *cx = id->cx;
    struct cx18_stream *s = &cx->streams[id->type];

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

    mutex_lock(&cx->serialize_lock);
    /* Stop radio */
    if (id->type == CX18_ENC_STREAM_TYPE_RAD &&
            v4l2_fh_is_singular_file(filp)) {
        /* 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,
                (v4l2_ctrl_g_ctrl(cx->cxhdl.video_mute) |
                (v4l2_ctrl_g_ctrl(cx->cxhdl.video_mute_yuv) << 8)));
        }
        /* Done! Unmute and continue. */
        cx18_unmute(cx);
    }

    v4l2_fh_del(fh);
    v4l2_fh_exit(fh);

    /* 'Unclaim' this stream */
    if (s->id == id->open_id)
        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 = kzalloc(sizeof(struct cx18_open_id), GFP_KERNEL);
    if (NULL == item) {
        CX18_DEBUG_WARN("nomem on v4l2 open\n");
        return -ENOMEM;
    }
    v4l2_fh_init(&item->fh, s->video_dev);

    item->cx = cx;
    item->type = s->type;

    item->open_id = cx->open_id++;
    filp->private_data = &item->fh;
    v4l2_fh_add(&item->fh);

    if (item->type == CX18_ENC_STREAM_TYPE_RAD &&
            v4l2_fh_is_singular_file(filp)) {
        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 */
                v4l2_fh_del(&item->fh);
                v4l2_fh_exit(&item->fh);
                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 %s\n",
             video_device_node_name(video_dev));
        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");
}