/*
 * u_uac1.c -- ALSA audio utilities for Gadget stack
 *
 * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
 * Copyright (C) 2008 Analog Devices, Inc
 *
 * Enter bugs at http://blackfin.uclinux.org/
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/ctype.h>
#include <linux/random.h>
#include <linux/syscalls.h>

#include "u_uac1.h"

/*
 * This component encapsulates the ALSA devices for USB audio gadget
 */

/*-------------------------------------------------------------------------*/

/**
 * Some ALSA internal helper functions
 */
static int snd_interval_refine_set(struct snd_interval *i, unsigned int val)
{
        struct snd_interval t;
        t.empty = 0;
        t.min = t.max = val;
        t.openmin = t.openmax = 0;
        t.integer = 1;
        return snd_interval_refine(i, &t);
}

static int _snd_pcm_hw_param_set(struct snd_pcm_hw_params *params,
                                 snd_pcm_hw_param_t var, unsigned int val,
                                 int dir)
{
        int changed;
        if (hw_is_mask(var)) {
                struct snd_mask *m = hw_param_mask(params, var);
                if (val == 0 && dir < 0) {
                        changed = -EINVAL;
                        snd_mask_none(m);
                } else {
                        if (dir > 0)
                                val++;
                        else if (dir < 0)
                                val--;
                        changed = snd_mask_refine_set(
                                        hw_param_mask(params, var), val);
                }
        } else if (hw_is_interval(var)) {
                struct snd_interval *i = hw_param_interval(params, var);
                if (val == 0 && dir < 0) {
                        changed = -EINVAL;
                        snd_interval_none(i);
                } else if (dir == 0)
                        changed = snd_interval_refine_set(i, val);
                else {
                        struct snd_interval t;
                        t.openmin = 1;
                        t.openmax = 1;
                        t.empty = 0;
                        t.integer = 0;
                        if (dir < 0) {
                                t.min = val - 1;
                                t.max = val;
                        } else {
                                t.min = val;
                                t.max = val+1;
                        }
                        changed = snd_interval_refine(i, &t);
                }
        } else
                return -EINVAL;
        if (changed) {
                params->cmask |= 1 << var;
                params->rmask |= 1 << var;
        }
        return changed;
}
/*-------------------------------------------------------------------------*/

/**
 * Set default hardware params
 */
static int playback_default_hw_params(struct gaudio_snd_dev *snd)
{
        struct snd_pcm_substream *substream = snd->substream;
        struct snd_pcm_hw_params *params;
        snd_pcm_sframes_t result;

       /*
        * SNDRV_PCM_ACCESS_RW_INTERLEAVED,
        * SNDRV_PCM_FORMAT_S16_LE
        * CHANNELS: 2
        * RATE: 48000
        */
        snd->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
        snd->format = SNDRV_PCM_FORMAT_S16_LE;
        snd->channels = 2;
        snd->rate = 48000;

        params = kzalloc(sizeof(*params), GFP_KERNEL);
        if (!params)
                return -ENOMEM;

        _snd_pcm_hw_params_any(params);
        _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_ACCESS,
                        snd->access, 0);
        _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_FORMAT,
                        snd->format, 0);
        _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_CHANNELS,
                        snd->channels, 0);
        _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_RATE,
                        snd->rate, 0);

        snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DROP, NULL);
        snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_HW_PARAMS, params);

        result = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_PREPARE, NULL);
        if (result < 0) {
                ERROR(snd->card,
                        "Preparing sound card failed: %d\n", (int)result);
                kfree(params);
                return result;
        }

        /* Store the hardware parameters */
        snd->access = params_access(params);
        snd->format = params_format(params);
        snd->channels = params_channels(params);
        snd->rate = params_rate(params);

        kfree(params);

        INFO(snd->card,
                "Hardware params: access %x, format %x, channels %d, rate %d\n",
                snd->access, snd->format, snd->channels, snd->rate);

        return 0;
}

/**
 * Playback audio buffer data by ALSA PCM device
 */
size_t u_audio_playback(struct gaudio *card, void *buf, size_t count)
{
        struct gaudio_snd_dev   *snd = &card->playback;
        struct snd_pcm_substream *substream = snd->substream;
        struct snd_pcm_runtime *runtime = substream->runtime;
        mm_segment_t old_fs;
        ssize_t result;
        snd_pcm_sframes_t frames;

try_again:
        if (runtime->status->state == SNDRV_PCM_STATE_XRUN ||
                runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
                result = snd_pcm_kernel_ioctl(substream,
                                SNDRV_PCM_IOCTL_PREPARE, NULL);
                if (result < 0) {
                        ERROR(card, "Preparing sound card failed: %d\n",
                                        (int)result);
                        return result;
                }
        }

        frames = bytes_to_frames(runtime, count);
        old_fs = get_fs();
        set_fs(KERNEL_DS);
        result = snd_pcm_lib_write(snd->substream, (void __user *)buf, frames);
        if (result != frames) {
                ERROR(card, "Playback error: %d\n", (int)result);
                set_fs(old_fs);
                goto try_again;
        }
        set_fs(old_fs);

        return 0;
}

int u_audio_get_playback_channels(struct gaudio *card)
{
        return card->playback.channels;
}

int u_audio_get_playback_rate(struct gaudio *card)
{
        return card->playback.rate;
}

/**
 * Open ALSA PCM and control device files
 * Initial the PCM or control device
 */
static int gaudio_open_snd_dev(struct gaudio *card)
{
        struct snd_pcm_file *pcm_file;
        struct gaudio_snd_dev *snd;
        struct f_uac1_opts *opts;
        char *fn_play, *fn_cap, *fn_cntl;

        opts = container_of(card->func.fi, struct f_uac1_opts, func_inst);
        fn_play = opts->fn_play;
        fn_cap = opts->fn_cap;
        fn_cntl = opts->fn_cntl;

        /* Open control device */
        snd = &card->control;
        snd->filp = filp_open(fn_cntl, O_RDWR, 0);
        if (IS_ERR(snd->filp)) {
                int ret = PTR_ERR(snd->filp);
                ERROR(card, "unable to open sound control device file: %s\n",
                                fn_cntl);
                snd->filp = NULL;
                return ret;
        }
        snd->card = card;

        /* Open PCM playback device and setup substream */
        snd = &card->playback;
        snd->filp = filp_open(fn_play, O_WRONLY, 0);
        if (IS_ERR(snd->filp)) {
                int ret = PTR_ERR(snd->filp);

                ERROR(card, "No such PCM playback device: %s\n", fn_play);
                snd->filp = NULL;
                return ret;
        }
        pcm_file = snd->filp->private_data;
        snd->substream = pcm_file->substream;
        snd->card = card;
        playback_default_hw_params(snd);

        /* Open PCM capture device and setup substream */
        snd = &card->capture;
        snd->filp = filp_open(fn_cap, O_RDONLY, 0);
        if (IS_ERR(snd->filp)) {
                ERROR(card, "No such PCM capture device: %s\n", fn_cap);
                snd->substream = NULL;
                snd->card = NULL;
                snd->filp = NULL;
        } else {
                pcm_file = snd->filp->private_data;
                snd->substream = pcm_file->substream;
                snd->card = card;
        }

        return 0;
}

/**
 * Close ALSA PCM and control device files
 */
static int gaudio_close_snd_dev(struct gaudio *gau)
{
        struct gaudio_snd_dev   *snd;

        /* Close control device */
        snd = &gau->control;
        if (snd->filp)
                filp_close(snd->filp, NULL);

        /* Close PCM playback device and setup substream */
        snd = &gau->playback;
        if (snd->filp)
                filp_close(snd->filp, NULL);

        /* Close PCM capture device and setup substream */
        snd = &gau->capture;
        if (snd->filp)
                filp_close(snd->filp, NULL);

        return 0;
}

/**
 * gaudio_setup - setup ALSA interface and preparing for USB transfer
 *
 * This sets up PCM, mixer or MIDI ALSA devices fore USB gadget using.
 *
 * Returns negative errno, or zero on success
 */
int gaudio_setup(struct gaudio *card)
{
        int     ret;

        ret = gaudio_open_snd_dev(card);
        if (ret)
                ERROR(card, "we need at least one control device\n");

        return ret;

}

/**
 * gaudio_cleanup - remove ALSA device interface
 *
 * This is called to free all resources allocated by @gaudio_setup().
 */
void gaudio_cleanup(struct gaudio *the_card)
{
        if (the_card)
                gaudio_close_snd_dev(the_card);
}