// SPDX-License-Identifier: GPL-2.0+
/*
 * u_audio.c -- interface to USB gadget "ALSA sound card" utilities
 *
 * Copyright (C) 2016
 * Author: Ruslan Bilovol <ruslan.bilovol@gmail.com>
 *
 * Sound card implementation was cut-and-pasted with changes
 * from f_uac2.c and has:
 *    Copyright (C) 2011
 *    Yadwinder Singh (yadi.brar01@gmail.com)
 *    Jaswinder Singh (jaswinder.singh@linaro.org)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/control.h>
#include <sound/tlv.h>
#include <linux/usb/audio.h>

#include "u_audio.h"

#define BUFF_SIZE_MAX   (PAGE_SIZE * 16)
#define PRD_SIZE_MAX    PAGE_SIZE
#define MIN_PERIODS     4

enum {
        UAC_FBACK_CTRL,
        UAC_P_PITCH_CTRL,
        UAC_MUTE_CTRL,
        UAC_VOLUME_CTRL,
        UAC_RATE_CTRL,
};

/* Runtime data params for one stream */
struct uac_rtd_params {
        struct snd_uac_chip *uac; /* parent chip */
        bool ep_enabled; /* if the ep is enabled */

        struct snd_pcm_substream *ss;

        /* Ring buffer */
        ssize_t hw_ptr;

        void *rbuf;

        unsigned int pitch;     /* Stream pitch ratio to 1000000 */
        unsigned int max_psize; /* MaxPacketSize of endpoint */

        struct usb_request **reqs;

        struct usb_request *req_fback; /* Feedback endpoint request */
        bool fb_ep_enabled; /* if the ep is enabled */

  /* Volume/Mute controls and their state */
  int fu_id; /* Feature Unit ID */
  struct snd_ctl_elem_id snd_kctl_volume_id;
  struct snd_ctl_elem_id snd_kctl_mute_id;
  s16 volume_min, volume_max, volume_res;
  s16 volume;
  int mute;

        struct snd_ctl_elem_id snd_kctl_rate_id; /* read-only current rate */
        int srate; /* selected samplerate */
        int active; /* playback/capture running */

  spinlock_t lock; /* lock for control transfers */

};

struct snd_uac_chip {
        struct g_audio *audio_dev;

        struct uac_rtd_params p_prm;
        struct uac_rtd_params c_prm;

        struct snd_card *card;
        struct snd_pcm *pcm;

        /* pre-calculated values for playback iso completion */
        unsigned long long p_residue_mil;
        unsigned int p_interval;
        unsigned int p_framesize;
};

static const struct snd_pcm_hardware uac_pcm_hardware = {
        .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
                 | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID
                 | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
        .rates = SNDRV_PCM_RATE_CONTINUOUS,
        .periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX,
        .buffer_bytes_max = BUFF_SIZE_MAX,
        .period_bytes_max = PRD_SIZE_MAX,
        .periods_min = MIN_PERIODS,
};

static void u_audio_set_fback_frequency(enum usb_device_speed speed,
                                        struct usb_ep *out_ep,
                                        unsigned long long freq,
                                        unsigned int pitch,
                                        void *buf)
{
        u32 ff = 0;
        const struct usb_endpoint_descriptor *ep_desc;

        /*
         * Because the pitch base is 1000000, the final divider here
         * will be 1000 * 1000000 = 1953125 << 9
         *
         * Instead of dealing with big numbers lets fold this 9 left shift
         */

        if (speed == USB_SPEED_FULL) {
                /*
                 * Full-speed feedback endpoints report frequency
                 * in samples/frame
                 * Format is encoded in Q10.10 left-justified in the 24 bits,
                 * so that it has a Q10.14 format.
                 *
                 * ff = (freq << 14) / 1000
                 */
                freq <<= 5;
        } else {
                /*
                 * High-speed feedback endpoints report frequency
                 * in samples/microframe.
                 * Format is encoded in Q12.13 fitted into four bytes so that
                 * the binary point is located between the second and the third
                 * byte fromat (that is Q16.16)
                 *
                 * ff = (freq << 16) / 8000
                 *
                 * Win10 and OSX UAC2 drivers require number of samples per packet
                 * in order to honor the feedback value.
                 * Linux snd-usb-audio detects the applied bit-shift automatically.
                 */
                ep_desc = out_ep->desc;
                freq <<= 4 + (ep_desc->bInterval - 1);
        }

        ff = DIV_ROUND_CLOSEST_ULL((freq * pitch), 1953125);

        *(__le32 *)buf = cpu_to_le32(ff);
}

static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req)
{
        unsigned int pending;
        unsigned int hw_ptr;
        int status = req->status;
        struct snd_pcm_substream *substream;
        struct snd_pcm_runtime *runtime;
        struct uac_rtd_params *prm = req->context;
        struct snd_uac_chip *uac = prm->uac;
        unsigned int frames, p_pktsize;
        unsigned long long pitched_rate_mil, p_pktsize_residue_mil,
                        residue_frames_mil, div_result;

        /* i/f shutting down */
        if (!prm->ep_enabled) {
                usb_ep_free_request(ep, req);
                return;
        }

        if (req->status == -ESHUTDOWN)
                return;

        /*
         * We can't really do much about bad xfers.
         * Afterall, the ISOCH xfers could fail legitimately.
         */
        if (status)
                pr_debug("%s: iso_complete status(%d) %d/%d\n",
                        __func__, status, req->actual, req->length);

        substream = prm->ss;

        /* Do nothing if ALSA isn't active */
        if (!substream)
                goto exit;

        snd_pcm_stream_lock(substream);

        runtime = substream->runtime;
        if (!runtime || !snd_pcm_running(substream)) {
                snd_pcm_stream_unlock(substream);
                goto exit;
        }

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                /*
                 * For each IN packet, take the quotient of the current data
                 * rate and the endpoint's interval as the base packet size.
                 * If there is a residue from this division, add it to the
                 * residue accumulator.
                 */
                unsigned long long p_interval_mil = uac->p_interval * 1000000ULL;

                pitched_rate_mil = (unsigned long long) prm->srate * prm->pitch;
                div_result = pitched_rate_mil;
                do_div(div_result, uac->p_interval);
                do_div(div_result, 1000000);
                frames = (unsigned int) div_result;

                pr_debug("p_srate %d, pitch %d, interval_mil %llu, frames %d\n",
                                prm->srate, prm->pitch, p_interval_mil, frames);

                p_pktsize = min_t(unsigned int,
                                        uac->p_framesize * frames,
                                        ep->maxpacket);

                if (p_pktsize < ep->maxpacket) {
                        residue_frames_mil = pitched_rate_mil - frames * p_interval_mil;
                        p_pktsize_residue_mil = uac->p_framesize * residue_frames_mil;
                } else
                        p_pktsize_residue_mil = 0;

                req->length = p_pktsize;
                uac->p_residue_mil += p_pktsize_residue_mil;

                /*
                 * Whenever there are more bytes in the accumulator p_residue_mil than we
                 * need to add one more sample frame, increase this packet's
                 * size and decrease the accumulator.
                 */
                div_result = uac->p_residue_mil;
                do_div(div_result, uac->p_interval);
                do_div(div_result, 1000000);
                if ((unsigned int) div_result >= uac->p_framesize) {
                        req->length += uac->p_framesize;
                        uac->p_residue_mil -= uac->p_framesize * p_interval_mil;
                        pr_debug("increased req length to %d\n", req->length);
                }
                pr_debug("remains uac->p_residue_mil %llu\n", uac->p_residue_mil);

                req->actual = req->length;
        }

        hw_ptr = prm->hw_ptr;

        /* Pack USB load in ALSA ring buffer */
        pending = runtime->dma_bytes - hw_ptr;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                if (unlikely(pending < req->actual)) {
                        memcpy(req->buf, runtime->dma_area + hw_ptr, pending);
                        memcpy(req->buf + pending, runtime->dma_area,
                               req->actual - pending);
                } else {
                        memcpy(req->buf, runtime->dma_area + hw_ptr,
                               req->actual);
                }
        } else {
                if (unlikely(pending < req->actual)) {
                        memcpy(runtime->dma_area + hw_ptr, req->buf, pending);
                        memcpy(runtime->dma_area, req->buf + pending,
                               req->actual - pending);
                } else {
                        memcpy(runtime->dma_area + hw_ptr, req->buf,
                               req->actual);
                }
        }

        /* update hw_ptr after data is copied to memory */
        prm->hw_ptr = (hw_ptr + req->actual) % runtime->dma_bytes;
        hw_ptr = prm->hw_ptr;
        snd_pcm_stream_unlock(substream);

        if ((hw_ptr % snd_pcm_lib_period_bytes(substream)) < req->actual)
                snd_pcm_period_elapsed(substream);

exit:
        if (usb_ep_queue(ep, req, GFP_ATOMIC))
                dev_err(uac->card->dev, "%d Error!\n", __LINE__);
}

static void u_audio_iso_fback_complete(struct usb_ep *ep,
                                       struct usb_request *req)
{
        struct uac_rtd_params *prm = req->context;
        struct snd_uac_chip *uac = prm->uac;
        struct g_audio *audio_dev = uac->audio_dev;
        int status = req->status;

        /* i/f shutting down */
        if (!prm->fb_ep_enabled) {
                kfree(req->buf);
                usb_ep_free_request(ep, req);
                return;
        }

        if (req->status == -ESHUTDOWN)
                return;

        /*
         * We can't really do much about bad xfers.
         * Afterall, the ISOCH xfers could fail legitimately.
         */
        if (status)
                pr_debug("%s: iso_complete status(%d) %d/%d\n",
                        __func__, status, req->actual, req->length);

        u_audio_set_fback_frequency(audio_dev->gadget->speed, audio_dev->out_ep,
                                    prm->srate, prm->pitch,
                                    req->buf);

        if (usb_ep_queue(ep, req, GFP_ATOMIC))
                dev_err(uac->card->dev, "%d Error!\n", __LINE__);
}

static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
        struct uac_rtd_params *prm;
        struct g_audio *audio_dev;
        struct uac_params *params;
        int err = 0;

        audio_dev = uac->audio_dev;
        params = &audio_dev->params;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                prm = &uac->p_prm;
        else
                prm = &uac->c_prm;

        /* Reset */
        prm->hw_ptr = 0;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
                prm->ss = substream;
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
                prm->ss = NULL;
                break;
        default:
                err = -EINVAL;
        }

        /* Clear buffer after Play stops */
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)
                memset(prm->rbuf, 0, prm->max_psize * params->req_number);

        return err;
}

static snd_pcm_uframes_t uac_pcm_pointer(struct snd_pcm_substream *substream)
{
        struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
        struct uac_rtd_params *prm;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                prm = &uac->p_prm;
        else
                prm = &uac->c_prm;

        return bytes_to_frames(substream->runtime, prm->hw_ptr);
}

static u64 uac_ssize_to_fmt(int ssize)
{
        u64 ret;

        switch (ssize) {
        case 3:
                ret = SNDRV_PCM_FMTBIT_S24_3LE;
                break;
        case 4:
                ret = SNDRV_PCM_FMTBIT_S32_LE;
                break;
        default:
                ret = SNDRV_PCM_FMTBIT_S16_LE;
                break;
        }

        return ret;
}

static int uac_pcm_open(struct snd_pcm_substream *substream)
{
        struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct g_audio *audio_dev;
        struct uac_params *params;
        struct uac_rtd_params *prm;
        int p_ssize, c_ssize;
        int p_chmask, c_chmask;

        audio_dev = uac->audio_dev;
        params = &audio_dev->params;
        p_ssize = params->p_ssize;
        c_ssize = params->c_ssize;
        p_chmask = params->p_chmask;
        c_chmask = params->c_chmask;
        uac->p_residue_mil = 0;

        runtime->hw = uac_pcm_hardware;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                runtime->hw.formats = uac_ssize_to_fmt(p_ssize);
                runtime->hw.channels_min = num_channels(p_chmask);
                prm = &uac->p_prm;
        } else {
                runtime->hw.formats = uac_ssize_to_fmt(c_ssize);
                runtime->hw.channels_min = num_channels(c_chmask);
                prm = &uac->c_prm;
        }

        runtime->hw.period_bytes_min = 2 * prm->max_psize
                                        / runtime->hw.periods_min;
        runtime->hw.rate_min = prm->srate;
        runtime->hw.rate_max = runtime->hw.rate_min;
        runtime->hw.channels_max = runtime->hw.channels_min;

        snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);

        return 0;
}

/* ALSA cries without these function pointers */
static int uac_pcm_null(struct snd_pcm_substream *substream)
{
        return 0;
}

static const struct snd_pcm_ops uac_pcm_ops = {
        .open = uac_pcm_open,
        .close = uac_pcm_null,
        .trigger = uac_pcm_trigger,
        .pointer = uac_pcm_pointer,
        .prepare = uac_pcm_null,
};

static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
{
        struct snd_uac_chip *uac = prm->uac;
        struct g_audio *audio_dev;
        struct uac_params *params;
        int i;

        if (!prm->ep_enabled)
                return;

        audio_dev = uac->audio_dev;
        params = &audio_dev->params;

        for (i = 0; i < params->req_number; i++) {
                if (prm->reqs[i]) {
                        if (usb_ep_dequeue(ep, prm->reqs[i]))
                                usb_ep_free_request(ep, prm->reqs[i]);
                        /*
                         * If usb_ep_dequeue() cannot successfully dequeue the
                         * request, the request will be freed by the completion
                         * callback.
                         */

                        prm->reqs[i] = NULL;
                }
        }

        prm->ep_enabled = false;

        if (usb_ep_disable(ep))
                dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
}

static inline void free_ep_fback(struct uac_rtd_params *prm, struct usb_ep *ep)
{
        struct snd_uac_chip *uac = prm->uac;

        if (!prm->fb_ep_enabled)
                return;

        if (prm->req_fback) {
                if (usb_ep_dequeue(ep, prm->req_fback)) {
                        kfree(prm->req_fback->buf);
                        usb_ep_free_request(ep, prm->req_fback);
                }
                prm->req_fback = NULL;
        }

        prm->fb_ep_enabled = false;

        if (usb_ep_disable(ep))
                dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
}

static void set_active(struct uac_rtd_params *prm, bool active)
{
        // notifying through the Rate ctrl
        unsigned long flags;

        spin_lock_irqsave(&prm->lock, flags);
        if (prm->active != active) {
                prm->active = active;
                snd_ctl_notify(prm->uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &prm->snd_kctl_rate_id);
        }
        spin_unlock_irqrestore(&prm->lock, flags);
}

int u_audio_set_capture_srate(struct g_audio *audio_dev, int srate)
{
        struct uac_params *params = &audio_dev->params;
        struct snd_uac_chip *uac = audio_dev->uac;
        struct uac_rtd_params *prm;
        int i;
        unsigned long flags;

        dev_dbg(&audio_dev->gadget->dev, "%s: srate %d\n", __func__, srate);
        prm = &uac->c_prm;
        for (i = 0; i < UAC_MAX_RATES; i++) {
                if (params->c_srates[i] == srate) {
                        spin_lock_irqsave(&prm->lock, flags);
                        prm->srate = srate;
                        spin_unlock_irqrestore(&prm->lock, flags);
                        return 0;
                }
                if (params->c_srates[i] == 0)
                        break;
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(u_audio_set_capture_srate);

int u_audio_get_capture_srate(struct g_audio *audio_dev, u32 *val)
{
        struct snd_uac_chip *uac = audio_dev->uac;
        struct uac_rtd_params *prm;
        unsigned long flags;

        prm = &uac->c_prm;
        spin_lock_irqsave(&prm->lock, flags);
        *val = prm->srate;
        spin_unlock_irqrestore(&prm->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(u_audio_get_capture_srate);

int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate)
{
        struct uac_params *params = &audio_dev->params;
        struct snd_uac_chip *uac = audio_dev->uac;
        struct uac_rtd_params *prm;
        int i;
        unsigned long flags;

        dev_dbg(&audio_dev->gadget->dev, "%s: srate %d\n", __func__, srate);
        prm = &uac->p_prm;
        for (i = 0; i < UAC_MAX_RATES; i++) {
                if (params->p_srates[i] == srate) {
                        spin_lock_irqsave(&prm->lock, flags);
                        prm->srate = srate;
                        spin_unlock_irqrestore(&prm->lock, flags);
                        return 0;
                }
                if (params->p_srates[i] == 0)
                        break;
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(u_audio_set_playback_srate);

int u_audio_get_playback_srate(struct g_audio *audio_dev, u32 *val)
{
        struct snd_uac_chip *uac = audio_dev->uac;
        struct uac_rtd_params *prm;
        unsigned long flags;

        prm = &uac->p_prm;
        spin_lock_irqsave(&prm->lock, flags);
        *val = prm->srate;
        spin_unlock_irqrestore(&prm->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(u_audio_get_playback_srate);

int u_audio_start_capture(struct g_audio *audio_dev)
{
        struct snd_uac_chip *uac = audio_dev->uac;
        struct usb_gadget *gadget = audio_dev->gadget;
        struct device *dev = &gadget->dev;
        struct usb_request *req, *req_fback;
        struct usb_ep *ep, *ep_fback;
        struct uac_rtd_params *prm;
        struct uac_params *params = &audio_dev->params;
        int req_len, i, ret;

        prm = &uac->c_prm;
        dev_dbg(dev, "start capture with rate %d\n", prm->srate);
        ep = audio_dev->out_ep;
        ret = config_ep_by_speed(gadget, &audio_dev->func, ep);
        if (ret < 0) {
                dev_err(dev, "config_ep_by_speed for out_ep failed (%d)\n", ret);
                return ret;
        }

        req_len = ep->maxpacket;

        prm->ep_enabled = true;
        ret = usb_ep_enable(ep);
        if (ret < 0) {
                dev_err(dev, "usb_ep_enable failed for out_ep (%d)\n", ret);
                return ret;
        }

        for (i = 0; i < params->req_number; i++) {
                if (!prm->reqs[i]) {
                        req = usb_ep_alloc_request(ep, GFP_ATOMIC);
                        if (req == NULL)
                                return -ENOMEM;

                        prm->reqs[i] = req;

                        req->zero = 0;
                        req->context = prm;
                        req->length = req_len;
                        req->complete = u_audio_iso_complete;
                        req->buf = prm->rbuf + i * ep->maxpacket;
                }

                if (usb_ep_queue(ep, prm->reqs[i], GFP_ATOMIC))
                        dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
        }

        set_active(&uac->c_prm, true);

        ep_fback = audio_dev->in_ep_fback;
        if (!ep_fback)
                return 0;

        /* Setup feedback endpoint */
        ret = config_ep_by_speed(gadget, &audio_dev->func, ep_fback);
        if (ret < 0) {
                dev_err(dev, "config_ep_by_speed in_ep_fback failed (%d)\n", ret);
                return ret; // TODO: Clean up out_ep
        }

        prm->fb_ep_enabled = true;
        ret = usb_ep_enable(ep_fback);
        if (ret < 0) {
                dev_err(dev, "usb_ep_enable failed for in_ep_fback (%d)\n", ret);
                return ret; // TODO: Clean up out_ep
        }
        req_len = ep_fback->maxpacket;

        req_fback = usb_ep_alloc_request(ep_fback, GFP_ATOMIC);
        if (req_fback == NULL)
                return -ENOMEM;

        prm->req_fback = req_fback;
        req_fback->zero = 0;
        req_fback->context = prm;
        req_fback->length = req_len;
        req_fback->complete = u_audio_iso_fback_complete;

        req_fback->buf = kzalloc(req_len, GFP_ATOMIC);
        if (!req_fback->buf)
                return -ENOMEM;

        /*
         * Configure the feedback endpoint's reported frequency.
         * Always start with original frequency since its deviation can't
         * be meauserd at start of playback
         */
        prm->pitch = 1000000;
        u_audio_set_fback_frequency(audio_dev->gadget->speed, ep,
                                    prm->srate, prm->pitch,
                                    req_fback->buf);

        if (usb_ep_queue(ep_fback, req_fback, GFP_ATOMIC))
                dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);

        return 0;
}
EXPORT_SYMBOL_GPL(u_audio_start_capture);

void u_audio_stop_capture(struct g_audio *audio_dev)
{
        struct snd_uac_chip *uac = audio_dev->uac;

        set_active(&uac->c_prm, false);
        if (audio_dev->in_ep_fback)
                free_ep_fback(&uac->c_prm, audio_dev->in_ep_fback);
        free_ep(&uac->c_prm, audio_dev->out_ep);
}
EXPORT_SYMBOL_GPL(u_audio_stop_capture);

int u_audio_start_playback(struct g_audio *audio_dev)
{
        struct snd_uac_chip *uac = audio_dev->uac;
        struct usb_gadget *gadget = audio_dev->gadget;
        struct device *dev = &gadget->dev;
        struct usb_request *req;
        struct usb_ep *ep;
        struct uac_rtd_params *prm;
        struct uac_params *params = &audio_dev->params;
        unsigned int factor;
        const struct usb_endpoint_descriptor *ep_desc;
        int req_len, i, ret;
        unsigned int p_pktsize;

        prm = &uac->p_prm;
        dev_dbg(dev, "start playback with rate %d\n", prm->srate);
        ep = audio_dev->in_ep;
        ret = config_ep_by_speed(gadget, &audio_dev->func, ep);
        if (ret < 0) {
                dev_err(dev, "config_ep_by_speed for in_ep failed (%d)\n", ret);
                return ret;
        }

        ep_desc = ep->desc;
        /*
         * Always start with original frequency
         */
        prm->pitch = 1000000;

        /* pre-calculate the playback endpoint's interval */
        if (gadget->speed == USB_SPEED_FULL)
                factor = 1000;
        else
                factor = 8000;

        /* pre-compute some values for iso_complete() */
        uac->p_framesize = params->p_ssize *
                            num_channels(params->p_chmask);
        uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
        p_pktsize = min_t(unsigned int,
                                uac->p_framesize *
                                        (prm->srate / uac->p_interval),
                                ep->maxpacket);

        req_len = p_pktsize;
        uac->p_residue_mil = 0;

        prm->ep_enabled = true;
        ret = usb_ep_enable(ep);
        if (ret < 0) {
                dev_err(dev, "usb_ep_enable failed for in_ep (%d)\n", ret);
                return ret;
        }

        for (i = 0; i < params->req_number; i++) {
                if (!prm->reqs[i]) {
                        req = usb_ep_alloc_request(ep, GFP_ATOMIC);
                        if (req == NULL)
                                return -ENOMEM;

                        prm->reqs[i] = req;

                        req->zero = 0;
                        req->context = prm;
                        req->length = req_len;
                        req->complete = u_audio_iso_complete;
                        req->buf = prm->rbuf + i * ep->maxpacket;
                }

                if (usb_ep_queue(ep, prm->reqs[i], GFP_ATOMIC))
                        dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
        }

        set_active(&uac->p_prm, true);

        return 0;
}
EXPORT_SYMBOL_GPL(u_audio_start_playback);

void u_audio_stop_playback(struct g_audio *audio_dev)
{
        struct snd_uac_chip *uac = audio_dev->uac;

        set_active(&uac->p_prm, false);
        free_ep(&uac->p_prm, audio_dev->in_ep);
}
EXPORT_SYMBOL_GPL(u_audio_stop_playback);

void u_audio_suspend(struct g_audio *audio_dev)
{
        struct snd_uac_chip *uac = audio_dev->uac;

        set_active(&uac->p_prm, false);
        set_active(&uac->c_prm, false);
}
EXPORT_SYMBOL_GPL(u_audio_suspend);

int u_audio_get_volume(struct g_audio *audio_dev, int playback, s16 *val)
{
        struct snd_uac_chip *uac = audio_dev->uac;
        struct uac_rtd_params *prm;
        unsigned long flags;

        if (playback)
                prm = &uac->p_prm;
        else
                prm = &uac->c_prm;

        spin_lock_irqsave(&prm->lock, flags);
        *val = prm->volume;
        spin_unlock_irqrestore(&prm->lock, flags);

        return 0;
}
EXPORT_SYMBOL_GPL(u_audio_get_volume);

int u_audio_set_volume(struct g_audio *audio_dev, int playback, s16 val)
{
        struct snd_uac_chip *uac = audio_dev->uac;
        struct uac_rtd_params *prm;
        unsigned long flags;
        int change = 0;

        if (playback)
                prm = &uac->p_prm;
        else
                prm = &uac->c_prm;

        spin_lock_irqsave(&prm->lock, flags);
        val = clamp(val, prm->volume_min, prm->volume_max);
        if (prm->volume != val) {
                prm->volume = val;
                change = 1;
        }
        spin_unlock_irqrestore(&prm->lock, flags);

        if (change)
                snd_ctl_notify(uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &prm->snd_kctl_volume_id);

        return 0;
}
EXPORT_SYMBOL_GPL(u_audio_set_volume);

int u_audio_get_mute(struct g_audio *audio_dev, int playback, int *val)
{
        struct snd_uac_chip *uac = audio_dev->uac;
        struct uac_rtd_params *prm;
        unsigned long flags;

        if (playback)
                prm = &uac->p_prm;
        else
                prm = &uac->c_prm;

        spin_lock_irqsave(&prm->lock, flags);
        *val = prm->mute;
        spin_unlock_irqrestore(&prm->lock, flags);

        return 0;
}
EXPORT_SYMBOL_GPL(u_audio_get_mute);

int u_audio_set_mute(struct g_audio *audio_dev, int playback, int val)
{
        struct snd_uac_chip *uac = audio_dev->uac;
        struct uac_rtd_params *prm;
        unsigned long flags;
        int change = 0;
        int mute;

        if (playback)
                prm = &uac->p_prm;
        else
                prm = &uac->c_prm;

        mute = val ? 1 : 0;

        spin_lock_irqsave(&prm->lock, flags);
        if (prm->mute != mute) {
                prm->mute = mute;
                change = 1;
        }
        spin_unlock_irqrestore(&prm->lock, flags);

        if (change)
                snd_ctl_notify(uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
                               &prm->snd_kctl_mute_id);

        return 0;
}
EXPORT_SYMBOL_GPL(u_audio_set_mute);


static int u_audio_pitch_info(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_info *uinfo)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        struct snd_uac_chip *uac = prm->uac;
        struct g_audio *audio_dev = uac->audio_dev;
        struct uac_params *params = &audio_dev->params;
        unsigned int pitch_min, pitch_max;

        pitch_min = (1000 - FBACK_SLOW_MAX) * 1000;
        pitch_max = (1000 + params->fb_max) * 1000;

        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count = 1;
        uinfo->value.integer.min = pitch_min;
        uinfo->value.integer.max = pitch_max;
        uinfo->value.integer.step = 1;
        return 0;
}

static int u_audio_pitch_get(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_value *ucontrol)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);

        ucontrol->value.integer.value[0] = prm->pitch;

        return 0;
}

static int u_audio_pitch_put(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_value *ucontrol)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        struct snd_uac_chip *uac = prm->uac;
        struct g_audio *audio_dev = uac->audio_dev;
        struct uac_params *params = &audio_dev->params;
        unsigned int val;
        unsigned int pitch_min, pitch_max;
        int change = 0;

        pitch_min = (1000 - FBACK_SLOW_MAX) * 1000;
        pitch_max = (1000 + params->fb_max) * 1000;

        val = ucontrol->value.integer.value[0];

        if (val < pitch_min)
                val = pitch_min;
        if (val > pitch_max)
                val = pitch_max;

        if (prm->pitch != val) {
                prm->pitch = val;
                change = 1;
        }

        return change;
}

static int u_audio_mute_info(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
        uinfo->count = 1;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max = 1;
        uinfo->value.integer.step = 1;

        return 0;
}

static int u_audio_mute_get(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_value *ucontrol)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        unsigned long flags;

        spin_lock_irqsave(&prm->lock, flags);
        ucontrol->value.integer.value[0] = !prm->mute;
        spin_unlock_irqrestore(&prm->lock, flags);

        return 0;
}

static int u_audio_mute_put(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_value *ucontrol)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        struct snd_uac_chip *uac = prm->uac;
        struct g_audio *audio_dev = uac->audio_dev;
        unsigned int val;
        unsigned long flags;
        int change = 0;

        val = !ucontrol->value.integer.value[0];

        spin_lock_irqsave(&prm->lock, flags);
        if (val != prm->mute) {
                prm->mute = val;
                change = 1;
        }
        spin_unlock_irqrestore(&prm->lock, flags);

        if (change && audio_dev->notify)
                audio_dev->notify(audio_dev, prm->fu_id, UAC_FU_MUTE);

        return change;
}

/*
 * TLV callback for mixer volume controls
 */
static int u_audio_volume_tlv(struct snd_kcontrol *kcontrol, int op_flag,
                         unsigned int size, unsigned int __user *_tlv)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        DECLARE_TLV_DB_MINMAX(scale, 0, 0);

        if (size < sizeof(scale))
                return -ENOMEM;

        /* UAC volume resolution is 1/256 dB, TLV is 1/100 dB */
        scale[2] = (prm->volume_min * 100) / 256;
        scale[3] = (prm->volume_max * 100) / 256;
        if (copy_to_user(_tlv, scale, sizeof(scale)))
                return -EFAULT;

        return 0;
}

static int u_audio_volume_info(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_info *uinfo)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);

        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count = 1;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max =
                (prm->volume_max - prm->volume_min + prm->volume_res - 1)
                / prm->volume_res;
        uinfo->value.integer.step = 1;

        return 0;
}

static int u_audio_volume_get(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_value *ucontrol)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        unsigned long flags;

        spin_lock_irqsave(&prm->lock, flags);
        ucontrol->value.integer.value[0] =
                        (prm->volume - prm->volume_min) / prm->volume_res;
        spin_unlock_irqrestore(&prm->lock, flags);

        return 0;
}

static int u_audio_volume_put(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_value *ucontrol)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        struct snd_uac_chip *uac = prm->uac;
        struct g_audio *audio_dev = uac->audio_dev;
        unsigned int val;
        s16 volume;
        unsigned long flags;
        int change = 0;

        val = ucontrol->value.integer.value[0];

        spin_lock_irqsave(&prm->lock, flags);
        volume = (val * prm->volume_res) + prm->volume_min;
        volume = clamp(volume, prm->volume_min, prm->volume_max);
        if (volume != prm->volume) {
                prm->volume = volume;
                change = 1;
        }
        spin_unlock_irqrestore(&prm->lock, flags);

        if (change && audio_dev->notify)
                audio_dev->notify(audio_dev, prm->fu_id, UAC_FU_VOLUME);

        return change;
}

static int get_max_srate(const int *srates)
{
        int i, max_srate = 0;

        for (i = 0; i < UAC_MAX_RATES; i++) {
                if (srates[i] == 0)
                        break;
                if (srates[i] > max_srate)
                        max_srate = srates[i];
        }
        return max_srate;
}

static int get_min_srate(const int *srates)
{
        int i, min_srate = INT_MAX;

        for (i = 0; i < UAC_MAX_RATES; i++) {
                if (srates[i] == 0)
                        break;
                if (srates[i] < min_srate)
                        min_srate = srates[i];
        }
        return min_srate;
}

static int u_audio_rate_info(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_info *uinfo)
{
        const int *srates;
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        struct snd_uac_chip *uac = prm->uac;
        struct g_audio *audio_dev = uac->audio_dev;
        struct uac_params *params = &audio_dev->params;

        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count = 1;

        if (prm == &uac->c_prm)
                srates = params->c_srates;
        else
                srates = params->p_srates;
        uinfo->value.integer.min = get_min_srate(srates);
        uinfo->value.integer.max = get_max_srate(srates);
        return 0;
}

static int u_audio_rate_get(struct snd_kcontrol *kcontrol,
                                                 struct snd_ctl_elem_value *ucontrol)
{
        struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
        unsigned long flags;

        spin_lock_irqsave(&prm->lock, flags);
        if (prm->active)
                ucontrol->value.integer.value[0] = prm->srate;
        else
                /* not active: reporting zero rate */
                ucontrol->value.integer.value[0] = 0;
        spin_unlock_irqrestore(&prm->lock, flags);
        return 0;
}

static struct snd_kcontrol_new u_audio_controls[]  = {
        [UAC_FBACK_CTRL] = {
    .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
    .name =         "Capture Pitch 1000000",
    .info =         u_audio_pitch_info,
    .get =          u_audio_pitch_get,
    .put =          u_audio_pitch_put,
  },
        [UAC_P_PITCH_CTRL] = {
                .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
                .name =         "Playback Pitch 1000000",
                .info =         u_audio_pitch_info,
                .get =          u_audio_pitch_get,
                .put =          u_audio_pitch_put,
        },
        [UAC_MUTE_CTRL] = {
                .iface =        SNDRV_CTL_ELEM_IFACE_MIXER,
                .name =         "", /* will be filled later */
                .info =         u_audio_mute_info,
                .get =          u_audio_mute_get,
                .put =          u_audio_mute_put,
        },
        [UAC_VOLUME_CTRL] = {
                .iface =        SNDRV_CTL_ELEM_IFACE_MIXER,
                .name =         "", /* will be filled later */
                .info =         u_audio_volume_info,
                .get =          u_audio_volume_get,
                .put =          u_audio_volume_put,
        },
        [UAC_RATE_CTRL] = {
                .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
                .name =         "", /* will be filled later */
                .access =       SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
                .info =         u_audio_rate_info,
                .get =          u_audio_rate_get,
        },
};

int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
                                        const char *card_name)
{
        struct snd_uac_chip *uac;
        struct snd_card *card;
        struct snd_pcm *pcm;
        struct snd_kcontrol *kctl;
        struct uac_params *params;
        int p_chmask, c_chmask;
        int i, err;

        if (!g_audio)
                return -EINVAL;

        uac = kzalloc_obj(*uac);
        if (!uac)
                return -ENOMEM;
        g_audio->uac = uac;
        uac->audio_dev = g_audio;

        params = &g_audio->params;
        p_chmask = params->p_chmask;
        c_chmask = params->c_chmask;

        if (c_chmask) {
                struct uac_rtd_params *prm = &uac->c_prm;

                spin_lock_init(&prm->lock);
                uac->c_prm.uac = uac;
                prm->max_psize = g_audio->out_ep_maxpsize;
                prm->srate = params->c_srates[0];

                prm->reqs = kzalloc_objs(struct usb_request *,
                                         params->req_number);
                if (!prm->reqs) {
                        err = -ENOMEM;
                        goto fail;
                }

                prm->rbuf = kcalloc(params->req_number, prm->max_psize,
                                GFP_KERNEL);
                if (!prm->rbuf) {
                        prm->max_psize = 0;
                        err = -ENOMEM;
                        goto fail;
                }
        }

        if (p_chmask) {
                struct uac_rtd_params *prm = &uac->p_prm;

                spin_lock_init(&prm->lock);
                uac->p_prm.uac = uac;
                prm->max_psize = g_audio->in_ep_maxpsize;
                prm->srate = params->p_srates[0];

                prm->reqs = kzalloc_objs(struct usb_request *,
                                         params->req_number);
                if (!prm->reqs) {
                        err = -ENOMEM;
                        goto fail;
                }

                prm->rbuf = kcalloc(params->req_number, prm->max_psize,
                                GFP_KERNEL);
                if (!prm->rbuf) {
                        prm->max_psize = 0;
                        err = -ENOMEM;
                        goto fail;
                }
        }

        /* Choose any slot, with no id */
        err = snd_card_new(&g_audio->gadget->dev,
                        -1, NULL, THIS_MODULE, 0, &card);
        if (err < 0)
                goto fail;

        uac->card = card;

        /*
         * Create first PCM device
         * Create a substream only for non-zero channel streams
         */
        err = snd_pcm_new(uac->card, pcm_name, 0,
                               p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
        if (err < 0)
                goto snd_fail;

        strscpy(pcm->name, pcm_name);
        pcm->private_data = uac;
        uac->pcm = pcm;

        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);

        /*
         * Create mixer and controls
         * Create only if it's required on USB side
         */
        if ((c_chmask && g_audio->in_ep_fback)
                        || (p_chmask && params->p_fu.id)
                        || (c_chmask && params->c_fu.id))
                strscpy(card->mixername, card_name);

        if (c_chmask && g_audio->in_ep_fback) {
                kctl = snd_ctl_new1(&u_audio_controls[UAC_FBACK_CTRL],
                                    &uac->c_prm);
                if (!kctl) {
                        err = -ENOMEM;
                        goto snd_fail;
                }

                kctl->id.device = pcm->device;
                kctl->id.subdevice = 0;

                err = snd_ctl_add(card, kctl);
                if (err < 0)
                        goto snd_fail;
        }

        if (p_chmask) {
                kctl = snd_ctl_new1(&u_audio_controls[UAC_P_PITCH_CTRL],
                                    &uac->p_prm);
                if (!kctl) {
                        err = -ENOMEM;
                        goto snd_fail;
                }

                kctl->id.device = pcm->device;
                kctl->id.subdevice = 0;

                err = snd_ctl_add(card, kctl);
                if (err < 0)
                        goto snd_fail;
        }

        for (i = 0; i <= SNDRV_PCM_STREAM_LAST; i++) {
                struct uac_rtd_params *prm;
                struct uac_fu_params *fu;
                char ctrl_name[24];
                char *direction;

                if (!pcm->streams[i].substream_count)
                        continue;

                if (i == SNDRV_PCM_STREAM_PLAYBACK) {
                        prm = &uac->p_prm;
                        fu = &params->p_fu;
                        direction = "Playback";
                } else {
                        prm = &uac->c_prm;
                        fu = &params->c_fu;
                        direction = "Capture";
                }

                prm->fu_id = fu->id;

                if (fu->mute_present) {
                        snprintf(ctrl_name, sizeof(ctrl_name),
                                        "PCM %s Switch", direction);

                        u_audio_controls[UAC_MUTE_CTRL].name = ctrl_name;

                        kctl = snd_ctl_new1(&u_audio_controls[UAC_MUTE_CTRL],
                                            prm);
                        if (!kctl) {
                                err = -ENOMEM;
                                goto snd_fail;
                        }

                        kctl->id.device = pcm->device;
                        kctl->id.subdevice = 0;

                        err = snd_ctl_add(card, kctl);
                        if (err < 0)
                                goto snd_fail;
                        prm->snd_kctl_mute_id = kctl->id;
                        prm->mute = 0;
                }

                if (fu->volume_present) {
                        snprintf(ctrl_name, sizeof(ctrl_name),
                                        "PCM %s Volume", direction);

                        u_audio_controls[UAC_VOLUME_CTRL].name = ctrl_name;

                        kctl = snd_ctl_new1(&u_audio_controls[UAC_VOLUME_CTRL],
                                            prm);
                        if (!kctl) {
                                err = -ENOMEM;
                                goto snd_fail;
                        }

                        kctl->id.device = pcm->device;
                        kctl->id.subdevice = 0;


                        kctl->tlv.c = u_audio_volume_tlv;
                        kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ |
                                        SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;

                        err = snd_ctl_add(card, kctl);
                        if (err < 0)
                                goto snd_fail;
                        prm->snd_kctl_volume_id = kctl->id;
                        prm->volume = fu->volume_max;
                        prm->volume_max = fu->volume_max;
                        prm->volume_min = fu->volume_min;
                        prm->volume_res = fu->volume_res;
                }

                /* Add rate control */
                snprintf(ctrl_name, sizeof(ctrl_name),
                                "%s Rate", direction);
                u_audio_controls[UAC_RATE_CTRL].name = ctrl_name;

                kctl = snd_ctl_new1(&u_audio_controls[UAC_RATE_CTRL], prm);
                if (!kctl) {
                        err = -ENOMEM;
                        goto snd_fail;
                }

                kctl->id.device = pcm->device;
                kctl->id.subdevice = 0;

                err = snd_ctl_add(card, kctl);
                if (err < 0)
                        goto snd_fail;
                prm->snd_kctl_rate_id = kctl->id;
        }

        strscpy(card->driver, card_name);
        strscpy(card->shortname, card_name);
        snprintf(card->longname, sizeof(card->longname), "%s %i",
                 card_name, card->dev->id);

        snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
                                       NULL, 0, BUFF_SIZE_MAX);

        err = snd_card_register(card);

        if (!err)
                return 0;

snd_fail:
        snd_card_free(card);
fail:
        kfree(uac->p_prm.reqs);
        kfree(uac->c_prm.reqs);
        kfree(uac->p_prm.rbuf);
        kfree(uac->c_prm.rbuf);
        kfree(uac);

        return err;
}
EXPORT_SYMBOL_GPL(g_audio_setup);

void g_audio_cleanup(struct g_audio *g_audio)
{
        struct snd_uac_chip *uac;
        struct snd_card *card;

        if (!g_audio || !g_audio->uac)
                return;

        uac = g_audio->uac;
        g_audio->uac = NULL;

        card = uac->card;
        if (card)
                snd_card_free_when_closed(card);

        kfree(uac->p_prm.reqs);
        kfree(uac->c_prm.reqs);
        kfree(uac->p_prm.rbuf);
        kfree(uac->c_prm.rbuf);
        kfree(uac);
}
EXPORT_SYMBOL_GPL(g_audio_cleanup);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
MODULE_AUTHOR("Ruslan Bilovol");