/*
 * Copyright (c) 2013 Federico Simoncelli
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL").
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * Fushicai USBTV007 Audio-Video Grabber Driver
 *
 * Product web site:
 * http://www.fushicai.com/products_detail/&productId=d05449ee-b690-42f9-a661-aa7353894bed.html
 *
 * No physical hardware was harmed running Windows during the
 * reverse-engineering activity
 */

#include <sound/core.h>
#include <sound/initval.h>
#include <sound/ac97_codec.h>
#include <sound/pcm_params.h>

#include "usbtv.h"

static const struct snd_pcm_hardware snd_usbtv_digital_hw = {
        .info = SNDRV_PCM_INFO_BATCH |
                SNDRV_PCM_INFO_MMAP |
                SNDRV_PCM_INFO_INTERLEAVED |
                SNDRV_PCM_INFO_BLOCK_TRANSFER |
                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,
        .period_bytes_min = 11059,
        .period_bytes_max = 13516,
        .periods_min = 2,
        .periods_max = 98,
        .buffer_bytes_max = 62720 * 8, /* value in usbaudio.c */
};

static int snd_usbtv_pcm_open(struct snd_pcm_substream *substream)
{
        struct usbtv *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;

        chip->snd_substream = substream;
        runtime->hw = snd_usbtv_digital_hw;

        return 0;
}

static int snd_usbtv_pcm_close(struct snd_pcm_substream *substream)
{
        struct usbtv *chip = snd_pcm_substream_chip(substream);

        if (atomic_read(&chip->snd_stream)) {
                atomic_set(&chip->snd_stream, 0);
                schedule_work(&chip->snd_trigger);
        }

        return 0;
}

static int snd_usbtv_prepare(struct snd_pcm_substream *substream)
{
        struct usbtv *chip = snd_pcm_substream_chip(substream);

        chip->snd_buffer_pos = 0;
        chip->snd_period_pos = 0;

        return 0;
}

static void usbtv_audio_urb_received(struct urb *urb)
{
        struct usbtv *chip = urb->context;
        struct snd_pcm_substream *substream = chip->snd_substream;
        struct snd_pcm_runtime *runtime = substream->runtime;
        size_t i, frame_bytes, chunk_length, buffer_pos, period_pos;
        int period_elapsed;
        unsigned long flags;
        void *urb_current;

        switch (urb->status) {
        case 0:
        case -ETIMEDOUT:
                break;
        case -ENOENT:
        case -EPROTO:
        case -ECONNRESET:
        case -ESHUTDOWN:
                return;
        default:
                dev_warn(chip->dev, "unknown audio urb status %i\n",
                        urb->status);
        }

        if (!atomic_read(&chip->snd_stream))
                return;

        frame_bytes = runtime->frame_bits >> 3;
        chunk_length = USBTV_CHUNK / frame_bytes;

        buffer_pos = chip->snd_buffer_pos;
        period_pos = chip->snd_period_pos;
        period_elapsed = 0;

        for (i = 0; i < urb->actual_length; i += USBTV_CHUNK_SIZE) {
                urb_current = urb->transfer_buffer + i + USBTV_AUDIO_HDRSIZE;

                if (buffer_pos + chunk_length >= runtime->buffer_size) {
                        size_t cnt = (runtime->buffer_size - buffer_pos) *
                                frame_bytes;
                        memcpy(runtime->dma_area + buffer_pos * frame_bytes,
                                urb_current, cnt);
                        memcpy(runtime->dma_area, urb_current + cnt,
                                chunk_length * frame_bytes - cnt);
                } else {
                        memcpy(runtime->dma_area + buffer_pos * frame_bytes,
                                urb_current, chunk_length * frame_bytes);
                }

                buffer_pos += chunk_length;
                period_pos += chunk_length;

                if (buffer_pos >= runtime->buffer_size)
                        buffer_pos -= runtime->buffer_size;

                if (period_pos >= runtime->period_size) {
                        period_pos -= runtime->period_size;
                        period_elapsed = 1;
                }
        }

        snd_pcm_stream_lock_irqsave(substream, flags);

        chip->snd_buffer_pos = buffer_pos;
        chip->snd_period_pos = period_pos;

        snd_pcm_stream_unlock_irqrestore(substream, flags);

        if (period_elapsed)
                snd_pcm_period_elapsed(substream);

        usb_submit_urb(urb, GFP_ATOMIC);
}

static int usbtv_audio_start(struct usbtv *chip)
{
        unsigned int pipe;
        static const u16 setup[][2] = {
                /* These seem to enable the device. */
                { USBTV_BASE + 0x0008, 0x0001 },
                { USBTV_BASE + 0x01d0, 0x00ff },
                { USBTV_BASE + 0x01d9, 0x0002 },

                { USBTV_BASE + 0x01da, 0x0013 },
                { USBTV_BASE + 0x01db, 0x0012 },
                { USBTV_BASE + 0x01e9, 0x0002 },
                { USBTV_BASE + 0x01ec, 0x006c },
                { USBTV_BASE + 0x0294, 0x0020 },
                { USBTV_BASE + 0x0255, 0x00cf },
                { USBTV_BASE + 0x0256, 0x0020 },
                { USBTV_BASE + 0x01eb, 0x0030 },
                { USBTV_BASE + 0x027d, 0x00a6 },
                { USBTV_BASE + 0x0280, 0x0011 },
                { USBTV_BASE + 0x0281, 0x0040 },
                { USBTV_BASE + 0x0282, 0x0011 },
                { USBTV_BASE + 0x0283, 0x0040 },
                { 0xf891, 0x0010 },

                /* this sets the input from composite */
                { USBTV_BASE + 0x0284, 0x00aa },
        };

        chip->snd_bulk_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (chip->snd_bulk_urb == NULL)
                goto err_alloc_urb;

        pipe = usb_rcvbulkpipe(chip->udev, USBTV_AUDIO_ENDP);

        chip->snd_bulk_urb->transfer_buffer = kzalloc(
                USBTV_AUDIO_URBSIZE, GFP_KERNEL);
        if (chip->snd_bulk_urb->transfer_buffer == NULL)
                goto err_transfer_buffer;

        usb_fill_bulk_urb(chip->snd_bulk_urb, chip->udev, pipe,
                chip->snd_bulk_urb->transfer_buffer, USBTV_AUDIO_URBSIZE,
                usbtv_audio_urb_received, chip);

        /* starting the stream */
        usbtv_set_regs(chip, setup, ARRAY_SIZE(setup));

        usb_clear_halt(chip->udev, pipe);
        usb_submit_urb(chip->snd_bulk_urb, GFP_ATOMIC);

        return 0;

err_transfer_buffer:
        usb_free_urb(chip->snd_bulk_urb);
        chip->snd_bulk_urb = NULL;

err_alloc_urb:
        return -ENOMEM;
}

static int usbtv_audio_stop(struct usbtv *chip)
{
        static const u16 setup[][2] = {
        /* The original windows driver sometimes sends also:
         *   { USBTV_BASE + 0x00a2, 0x0013 }
         * but it seems useless and its real effects are untested at
         * the moment.
         */
                { USBTV_BASE + 0x027d, 0x0000 },
                { USBTV_BASE + 0x0280, 0x0010 },
                { USBTV_BASE + 0x0282, 0x0010 },
        };

        if (chip->snd_bulk_urb) {
                usb_kill_urb(chip->snd_bulk_urb);
                kfree(chip->snd_bulk_urb->transfer_buffer);
                usb_free_urb(chip->snd_bulk_urb);
                chip->snd_bulk_urb = NULL;
        }

        usbtv_set_regs(chip, setup, ARRAY_SIZE(setup));

        return 0;
}

void usbtv_audio_suspend(struct usbtv *usbtv)
{
        if (atomic_read(&usbtv->snd_stream) && usbtv->snd_bulk_urb)
                usb_kill_urb(usbtv->snd_bulk_urb);
}

void usbtv_audio_resume(struct usbtv *usbtv)
{
        if (atomic_read(&usbtv->snd_stream) && usbtv->snd_bulk_urb)
                usb_submit_urb(usbtv->snd_bulk_urb, GFP_ATOMIC);
}

static void snd_usbtv_trigger(struct work_struct *work)
{
        struct usbtv *chip = container_of(work, struct usbtv, snd_trigger);

        if (!chip->snd)
                return;

        if (atomic_read(&chip->snd_stream))
                usbtv_audio_start(chip);
        else
                usbtv_audio_stop(chip);
}

static int snd_usbtv_card_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct usbtv *chip = snd_pcm_substream_chip(substream);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                atomic_set(&chip->snd_stream, 1);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                atomic_set(&chip->snd_stream, 0);
                break;
        default:
                return -EINVAL;
        }

        schedule_work(&chip->snd_trigger);

        return 0;
}

static snd_pcm_uframes_t snd_usbtv_pointer(struct snd_pcm_substream *substream)
{
        struct usbtv *chip = snd_pcm_substream_chip(substream);

        return chip->snd_buffer_pos;
}

static const struct snd_pcm_ops snd_usbtv_pcm_ops = {
        .open = snd_usbtv_pcm_open,
        .close = snd_usbtv_pcm_close,
        .prepare = snd_usbtv_prepare,
        .trigger = snd_usbtv_card_trigger,
        .pointer = snd_usbtv_pointer,
};

int usbtv_audio_init(struct usbtv *usbtv)
{
        int rv;
        struct snd_card *card;
        struct snd_pcm *pcm;

        INIT_WORK(&usbtv->snd_trigger, snd_usbtv_trigger);
        atomic_set(&usbtv->snd_stream, 0);

        rv = snd_card_new(&usbtv->udev->dev, SNDRV_DEFAULT_IDX1, "usbtv",
                THIS_MODULE, 0, &card);
        if (rv < 0)
                return rv;

        strscpy(card->driver, usbtv->dev->driver->name, sizeof(card->driver));
        strscpy(card->shortname, "usbtv", sizeof(card->shortname));
        snprintf(card->longname, sizeof(card->longname),
                "USBTV Audio at bus %d device %d", usbtv->udev->bus->busnum,
                usbtv->udev->devnum);

        snd_card_set_dev(card, usbtv->dev);

        usbtv->snd = card;

        rv = snd_pcm_new(card, "USBTV Audio", 0, 0, 1, &pcm);
        if (rv < 0)
                goto err;

        strscpy(pcm->name, "USBTV Audio Input", sizeof(pcm->name));
        pcm->info_flags = 0;
        pcm->private_data = usbtv;

        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_usbtv_pcm_ops);
        snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
                NULL, USBTV_AUDIO_BUFFER, USBTV_AUDIO_BUFFER);

        rv = snd_card_register(card);
        if (rv)
                goto err;

        return 0;

err:
        usbtv->snd = NULL;
        snd_card_free(card);

        return rv;
}

void usbtv_audio_free(struct usbtv *usbtv)
{
        cancel_work_sync(&usbtv->snd_trigger);

        if (usbtv->snd && usbtv->udev) {
                snd_card_free_when_closed(usbtv->snd);
                usbtv->snd = NULL;
        }
}