/*
 *  ALSA PCM device for the
 *  ALSA interface to ivtv PCM capture streams
 *
 *  Copyright (C) 2009,2012  Andy Walls <awalls@md.metrocast.net>
 *  Copyright (C) 2009  Devin Heitmueller <dheitmueller@kernellabs.com>
 *
 *  Portions of this work were sponsored by ONELAN Limited for the cx18 driver
 *
 *  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 "ivtv-driver.h"
#include "ivtv-queue.h"
#include "ivtv-streams.h"
#include "ivtv-fileops.h"
#include "ivtv-alsa.h"
#include "ivtv-alsa-pcm.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) \
                        pr_info("ivtv-alsa-pcm %s: " fmt, __func__, ##arg); \
        } while (0)

static struct snd_pcm_hardware snd_ivtv_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, */
};

static void ivtv_alsa_announce_pcm_data(struct snd_ivtv_card *itvsc,
                                        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("ivtv alsa announce ptr=%p data=%p num_bytes=%zd\n", itvsc,
                pcm_data, num_bytes);

        substream = itvsc->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 = itvsc->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);

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

        itvsc->capture_transfer_done += length;
        if (itvsc->capture_transfer_done >=
            runtime->period_size) {
                itvsc->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_ivtv_pcm_capture_open(struct snd_pcm_substream *substream)
{
        struct snd_ivtv_card *itvsc = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct v4l2_device *v4l2_dev = itvsc->v4l2_dev;
        struct ivtv *itv = to_ivtv(v4l2_dev);
        struct ivtv_stream *s;
        struct ivtv_open_id item;
        int ret;

        /* Instruct the CX2341[56] to start sending packets */
        snd_ivtv_lock(itvsc);
        s = &itv->streams[IVTV_ENC_STREAM_TYPE_PCM];

        v4l2_fh_init(&item.fh, s->vdev);
        item.itv = itv;
        item.type = s->type;

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

        if (test_bit(IVTV_F_S_STREAMOFF, &s->s_flags) ||
            test_and_set_bit(IVTV_F_S_STREAMING, &s->s_flags)) {
                /* We're already streaming.  No additional action required */
                snd_ivtv_unlock(itvsc);
                return 0;
        }


        runtime->hw = snd_ivtv_hw_capture;
        snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
        itvsc->capture_pcm_substream = substream;
        runtime->private_data = itv;

        itv->pcm_announce_callback = ivtv_alsa_announce_pcm_data;

        /* Not currently streaming, so start it up */
        set_bit(IVTV_F_S_STREAMING, &s->s_flags);
        ret = ivtv_start_v4l2_encode_stream(s);
        snd_ivtv_unlock(itvsc);

        return ret;
}

static int snd_ivtv_pcm_capture_close(struct snd_pcm_substream *substream)
{
        struct snd_ivtv_card *itvsc = snd_pcm_substream_chip(substream);
        struct v4l2_device *v4l2_dev = itvsc->v4l2_dev;
        struct ivtv *itv = to_ivtv(v4l2_dev);
        struct ivtv_stream *s;

        /* Instruct the ivtv to stop sending packets */
        snd_ivtv_lock(itvsc);
        s = &itv->streams[IVTV_ENC_STREAM_TYPE_PCM];
        ivtv_stop_v4l2_encode_stream(s, 0);
        clear_bit(IVTV_F_S_STREAMING, &s->s_flags);

        ivtv_release_stream(s);

        itv->pcm_announce_callback = NULL;
        snd_ivtv_unlock(itvsc);

        return 0;
}

static int snd_ivtv_pcm_ioctl(struct snd_pcm_substream *substream,
                     unsigned int cmd, void *arg)
{
        struct snd_ivtv_card *itvsc = snd_pcm_substream_chip(substream);
        int ret;

        snd_ivtv_lock(itvsc);
        ret = snd_pcm_lib_ioctl(substream, cmd, arg);
        snd_ivtv_unlock(itvsc);
        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_ivtv_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_ivtv_pcm_hw_free(struct snd_pcm_substream *substream)
{
        struct snd_ivtv_card *itvsc = snd_pcm_substream_chip(substream);
        unsigned long flags;

        spin_lock_irqsave(&itvsc->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(&itvsc->slock, flags);

        return 0;
}

static int snd_ivtv_pcm_prepare(struct snd_pcm_substream *substream)
{
        struct snd_ivtv_card *itvsc = snd_pcm_substream_chip(substream);

        itvsc->hwptr_done_capture = 0;
        itvsc->capture_transfer_done = 0;

        return 0;
}

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

static
snd_pcm_uframes_t snd_ivtv_pcm_pointer(struct snd_pcm_substream *substream)
{
        unsigned long flags;
        snd_pcm_uframes_t hwptr_done;
        struct snd_ivtv_card *itvsc = snd_pcm_substream_chip(substream);

        spin_lock_irqsave(&itvsc->slock, flags);
        hwptr_done = itvsc->hwptr_done_capture;
        spin_unlock_irqrestore(&itvsc->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_ivtv_pcm_capture_ops = {
        .open           = snd_ivtv_pcm_capture_open,
        .close          = snd_ivtv_pcm_capture_close,
        .ioctl          = snd_ivtv_pcm_ioctl,
        .hw_params      = snd_ivtv_pcm_hw_params,
        .hw_free        = snd_ivtv_pcm_hw_free,
        .prepare        = snd_ivtv_pcm_prepare,
        .trigger        = snd_ivtv_pcm_trigger,
        .pointer        = snd_ivtv_pcm_pointer,
        .page           = snd_pcm_get_vmalloc_page,
};

int snd_ivtv_pcm_create(struct snd_ivtv_card *itvsc)
{
        struct snd_pcm *sp;
        struct snd_card *sc = itvsc->sc;
        struct v4l2_device *v4l2_dev = itvsc->v4l2_dev;
        struct ivtv *itv = to_ivtv(v4l2_dev);
        int ret;

        ret = snd_pcm_new(sc, "CX2341[56] PCM",
                          0, /* PCM device 0, the only one for this card */
                          0, /* 0 playback substreams */
                          1, /* 1 capture substream */
                          &sp);
        if (ret) {
                IVTV_ALSA_ERR("%s: snd_ivtv_pcm_create() failed with err %d\n",
                              __func__, ret);
                goto err_exit;
        }

        spin_lock_init(&itvsc->slock);

        snd_pcm_set_ops(sp, SNDRV_PCM_STREAM_CAPTURE,
                        &snd_ivtv_pcm_capture_ops);
        sp->info_flags = 0;
        sp->private_data = itvsc;
        strlcpy(sp->name, itv->card_name, sizeof(sp->name));

        return 0;

err_exit:
        return ret;
}