cx18-alsa-pcm.c

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/*
 *  ALSA PCM device for the
 *  ALSA interface to cx18 PCM capture streams
 *
 *  Copyright (C) 2009  Andy Walls <[email protected]>
 *  Copyright (C) 2009  Devin Heitmueller <[email protected]>
 *
 *  Portions of this work were sponsored by ONELAN Limited.
 *
 *  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 <linux/init.h>
#include <linux/kernel.h>
#include <linux/vmalloc.h>

#include <media/v4l2-device.h>

#include <sound/core.h>
#include <sound/pcm.h>

#include "cx18-driver.h"
#include "cx18-queue.h"
#include "cx18-streams.h"
#include "cx18-fileops.h"
#include "cx18-alsa.h"

static unsigned int pcm_debug;
module_param(pcm_debug, int, 0644);
MODULE_PARM_DESC(pcm_debug, "enable debug messages for pcm");

#define dprintk(fmt, arg...) do {                   \
        if (pcm_debug)                      \
        printk(KERN_INFO "cx18-alsa-pcm %s: " fmt,      \
                  __func__, ##arg);             \
    } while (0)

static struct snd_pcm_hardware snd_cx18_hw_capture = {
    .info = SNDRV_PCM_INFO_BLOCK_TRANSFER |
        SNDRV_PCM_INFO_MMAP           |
        SNDRV_PCM_INFO_INTERLEAVED    |
        SNDRV_PCM_INFO_MMAP_VALID,

    .formats = SNDRV_PCM_FMTBIT_S16_LE,

    .rates = SNDRV_PCM_RATE_48000,

    .rate_min = 48000,
    .rate_max = 48000,
    .channels_min = 2,
    .channels_max = 2,
    .buffer_bytes_max = 62720 * 8,  /* just about the value in usbaudio.c */
    .period_bytes_min = 64,     /* 12544/2, */
    .period_bytes_max = 12544,
    .periods_min = 2,
    .periods_max = 98,      /* 12544, */
};

void cx18_alsa_announce_pcm_data(struct snd_cx18_card *cxsc, u8 *pcm_data,
                 size_t num_bytes)
{
    struct snd_pcm_substream *substream;
    struct snd_pcm_runtime *runtime;
    unsigned int oldptr;
    unsigned int stride;
    int period_elapsed = 0;
    int length;

    dprintk("cx18 alsa announce ptr=%p data=%p num_bytes=%zd\n", cxsc,
        pcm_data, num_bytes);

    substream = cxsc->capture_pcm_substream;
    if (substream == NULL) {
        dprintk("substream was NULL\n");
        return;
    }

    runtime = substream->runtime;
    if (runtime == NULL) {
        dprintk("runtime was NULL\n");
        return;
    }

    stride = runtime->frame_bits >> 3;
    if (stride == 0) {
        dprintk("stride is zero\n");
        return;
    }

    length = num_bytes / stride;
    if (length == 0) {
        dprintk("%s: length was zero\n", __func__);
        return;
    }

    if (runtime->dma_area == NULL) {
        dprintk("dma area was NULL - ignoring\n");
        return;
    }

    oldptr = cxsc->hwptr_done_capture;
    if (oldptr + length >= runtime->buffer_size) {
        unsigned int cnt =
            runtime->buffer_size - oldptr;
        memcpy(runtime->dma_area + oldptr * stride, pcm_data,
               cnt * stride);
        memcpy(runtime->dma_area, pcm_data + cnt * stride,
               length * stride - cnt * stride);
    } else {
        memcpy(runtime->dma_area + oldptr * stride, pcm_data,
               length * stride);
    }
    snd_pcm_stream_lock(substream);

    cxsc->hwptr_done_capture += length;
    if (cxsc->hwptr_done_capture >=
        runtime->buffer_size)
        cxsc->hwptr_done_capture -=
            runtime->buffer_size;

    cxsc->capture_transfer_done += length;
    if (cxsc->capture_transfer_done >=
        runtime->period_size) {
        cxsc->capture_transfer_done -=
            runtime->period_size;
        period_elapsed = 1;
    }

    snd_pcm_stream_unlock(substream);

    if (period_elapsed)
        snd_pcm_period_elapsed(substream);
}

static int snd_cx18_pcm_capture_open(struct snd_pcm_substream *substream)
{
    struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
    struct cx18 *cx = to_cx18(v4l2_dev);
    struct cx18_stream *s;
    struct cx18_open_id item;
    int ret;

    /* Instruct the cx18 to start sending packets */
    snd_cx18_lock(cxsc);
    s = &cx->streams[CX18_ENC_STREAM_TYPE_PCM];

    item.cx = cx;
    item.type = s->type;
    item.open_id = cx->open_id++;

    /* See if the stream is available */
    if (cx18_claim_stream(&item, item.type)) {
        /* No, it's already in use */
        snd_cx18_unlock(cxsc);
        return -EBUSY;
    }

    if (test_bit(CX18_F_S_STREAMOFF, &s->s_flags) ||
        test_and_set_bit(CX18_F_S_STREAMING, &s->s_flags)) {
        /* We're already streaming.  No additional action required */
        snd_cx18_unlock(cxsc);
        return 0;
    }


    runtime->hw = snd_cx18_hw_capture;
    snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
    cxsc->capture_pcm_substream = substream;
    runtime->private_data = cx;

    cx->pcm_announce_callback = cx18_alsa_announce_pcm_data;

    /* Not currently streaming, so start it up */
    set_bit(CX18_F_S_STREAMING, &s->s_flags);
    ret = cx18_start_v4l2_encode_stream(s);
    snd_cx18_unlock(cxsc);

    return ret;
}

static int snd_cx18_pcm_capture_close(struct snd_pcm_substream *substream)
{
    struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
    struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
    struct cx18 *cx = to_cx18(v4l2_dev);
    struct cx18_stream *s;

    /* Instruct the cx18 to stop sending packets */
    snd_cx18_lock(cxsc);
    s = &cx->streams[CX18_ENC_STREAM_TYPE_PCM];
    cx18_stop_v4l2_encode_stream(s, 0);
    clear_bit(CX18_F_S_STREAMING, &s->s_flags);

    cx18_release_stream(s);

    cx->pcm_announce_callback = NULL;
    snd_cx18_unlock(cxsc);

    return 0;
}

static int snd_cx18_pcm_ioctl(struct snd_pcm_substream *substream,
             unsigned int cmd, void *arg)
{
    struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
    int ret;

    snd_cx18_lock(cxsc);
    ret = snd_pcm_lib_ioctl(substream, cmd, arg);
    snd_cx18_unlock(cxsc);
    return ret;
}


static int snd_pcm_alloc_vmalloc_buffer(struct snd_pcm_substream *subs,
                    size_t size)
{
    struct snd_pcm_runtime *runtime = subs->runtime;

    dprintk("Allocating vbuffer\n");
    if (runtime->dma_area) {
        if (runtime->dma_bytes > size)
            return 0;

        vfree(runtime->dma_area);
    }
    runtime->dma_area = vmalloc(size);
    if (!runtime->dma_area)
        return -ENOMEM;

    runtime->dma_bytes = size;

    return 0;
}

static int snd_cx18_pcm_hw_params(struct snd_pcm_substream *substream,
             struct snd_pcm_hw_params *params)
{
    dprintk("%s called\n", __func__);

    return snd_pcm_alloc_vmalloc_buffer(substream,
                       params_buffer_bytes(params));
}

static int snd_cx18_pcm_hw_free(struct snd_pcm_substream *substream)
{
    struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
    unsigned long flags;

    spin_lock_irqsave(&cxsc->slock, flags);
    if (substream->runtime->dma_area) {
        dprintk("freeing pcm capture region\n");
        vfree(substream->runtime->dma_area);
        substream->runtime->dma_area = NULL;
    }
    spin_unlock_irqrestore(&cxsc->slock, flags);

    return 0;
}

static int snd_cx18_pcm_prepare(struct snd_pcm_substream *substream)
{
    struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);

    cxsc->hwptr_done_capture = 0;
    cxsc->capture_transfer_done = 0;

    return 0;
}

static int snd_cx18_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
    return 0;
}

static
snd_pcm_uframes_t snd_cx18_pcm_pointer(struct snd_pcm_substream *substream)
{
    unsigned long flags;
    snd_pcm_uframes_t hwptr_done;
    struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);

    spin_lock_irqsave(&cxsc->slock, flags);
    hwptr_done = cxsc->hwptr_done_capture;
    spin_unlock_irqrestore(&cxsc->slock, flags);

    return hwptr_done;
}

static struct page *snd_pcm_get_vmalloc_page(struct snd_pcm_substream *subs,
                         unsigned long offset)
{
    void *pageptr = subs->runtime->dma_area + offset;

    return vmalloc_to_page(pageptr);
}

static struct snd_pcm_ops snd_cx18_pcm_capture_ops = {
    .open       = snd_cx18_pcm_capture_open,
    .close      = snd_cx18_pcm_capture_close,
    .ioctl      = snd_cx18_pcm_ioctl,
    .hw_params  = snd_cx18_pcm_hw_params,
    .hw_free    = snd_cx18_pcm_hw_free,
    .prepare    = snd_cx18_pcm_prepare,
    .trigger    = snd_cx18_pcm_trigger,
    .pointer    = snd_cx18_pcm_pointer,
    .page       = snd_pcm_get_vmalloc_page,
};

int snd_cx18_pcm_create(struct snd_cx18_card *cxsc)
{
    struct snd_pcm *sp;
    struct snd_card *sc = cxsc->sc;
    struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
    struct cx18 *cx = to_cx18(v4l2_dev);
    int ret;

    ret = snd_pcm_new(sc, "CX23418 PCM",
              0, /* PCM device 0, the only one for this card */
              0, /* 0 playback substreams */
              1, /* 1 capture substream */
              &sp);
    if (ret) {
        CX18_ALSA_ERR("%s: snd_cx18_pcm_create() failed with err %d\n",
                  __func__, ret);
        goto err_exit;
    }

    spin_lock_init(&cxsc->slock);

    snd_pcm_set_ops(sp, SNDRV_PCM_STREAM_CAPTURE,
            &snd_cx18_pcm_capture_ops);
    sp->info_flags = 0;
    sp->private_data = cxsc;
    strlcpy(sp->name, cx->card_name, sizeof(sp->name));

    return 0;

err_exit:
    return ret;
}