pcm.c

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/*
 * Linux driver for TerraTec DMX 6Fire USB
 *
 * PCM driver
 *
 * Author:  Torsten Schenk <[email protected]>
 * Created: Jan 01, 2011
 * Copyright:   (C) Torsten Schenk
 *
 * 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.
 */

#include "pcm.h"
#include "chip.h"
#include "comm.h"
#include "control.h"

enum {
    OUT_N_CHANNELS = 6, IN_N_CHANNELS = 4
};

/* keep next two synced with
 * FW_EP_W_MAX_PACKET_SIZE[] and RATES_MAX_PACKET_SIZE
 * and CONTROL_RATE_XXX in control.h */
static const int rates_in_packet_size[] = { 228, 228, 420, 420, 404, 404 };
static const int rates_out_packet_size[] = { 228, 228, 420, 420, 604, 604 };
static const int rates[] = { 44100, 48000, 88200, 96000, 176400, 192000 };
static const int rates_alsaid[] = {
    SNDRV_PCM_RATE_44100, SNDRV_PCM_RATE_48000,
    SNDRV_PCM_RATE_88200, SNDRV_PCM_RATE_96000,
    SNDRV_PCM_RATE_176400, SNDRV_PCM_RATE_192000 };

enum { /* settings for pcm */
    OUT_EP = 6, IN_EP = 2, MAX_BUFSIZE = 128 * 1024
};

enum { /* pcm streaming states */
    STREAM_DISABLED, /* no pcm streaming */
    STREAM_STARTING, /* pcm streaming requested, waiting to become ready */
    STREAM_RUNNING, /* pcm streaming running */
    STREAM_STOPPING
};

static const struct snd_pcm_hardware pcm_hw = {
    .info = SNDRV_PCM_INFO_MMAP |
        SNDRV_PCM_INFO_INTERLEAVED |
        SNDRV_PCM_INFO_BLOCK_TRANSFER |
        SNDRV_PCM_INFO_MMAP_VALID |
        SNDRV_PCM_INFO_BATCH,

    .formats = SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE,

    .rates = SNDRV_PCM_RATE_44100 |
        SNDRV_PCM_RATE_48000 |
        SNDRV_PCM_RATE_88200 |
        SNDRV_PCM_RATE_96000 |
        SNDRV_PCM_RATE_176400 |
        SNDRV_PCM_RATE_192000,

    .rate_min = 44100,
    .rate_max = 192000,
    .channels_min = 1,
    .channels_max = 0, /* set in pcm_open, depending on capture/playback */
    .buffer_bytes_max = MAX_BUFSIZE,
    .period_bytes_min = PCM_N_PACKETS_PER_URB * (PCM_MAX_PACKET_SIZE - 4),
    .period_bytes_max = MAX_BUFSIZE,
    .periods_min = 2,
    .periods_max = 1024
};

static int usb6fire_pcm_set_rate(struct pcm_runtime *rt)
{
    int ret;
    struct control_runtime *ctrl_rt = rt->chip->control;

    ctrl_rt->usb_streaming = false;
    ret = ctrl_rt->update_streaming(ctrl_rt);
    if (ret < 0) {
        snd_printk(KERN_ERR PREFIX "error stopping streaming while "
                "setting samplerate %d.\n", rates[rt->rate]);
        return ret;
    }

    ret = ctrl_rt->set_rate(ctrl_rt, rt->rate);
    if (ret < 0) {
        snd_printk(KERN_ERR PREFIX "error setting samplerate %d.\n",
                rates[rt->rate]);
        return ret;
    }

    ret = ctrl_rt->set_channels(ctrl_rt, OUT_N_CHANNELS, IN_N_CHANNELS,
            false, false);
    if (ret < 0) {
        snd_printk(KERN_ERR PREFIX "error initializing channels "
                "while setting samplerate %d.\n",
                rates[rt->rate]);
        return ret;
    }

    ctrl_rt->usb_streaming = true;
    ret = ctrl_rt->update_streaming(ctrl_rt);
    if (ret < 0) {
        snd_printk(KERN_ERR PREFIX "error starting streaming while "
                "setting samplerate %d.\n", rates[rt->rate]);
        return ret;
    }

    rt->in_n_analog = IN_N_CHANNELS;
    rt->out_n_analog = OUT_N_CHANNELS;
    rt->in_packet_size = rates_in_packet_size[rt->rate];
    rt->out_packet_size = rates_out_packet_size[rt->rate];
    return 0;
}

static struct pcm_substream *usb6fire_pcm_get_substream(
        struct snd_pcm_substream *alsa_sub)
{
    struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);

    if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
        return &rt->playback;
    else if (alsa_sub->stream == SNDRV_PCM_STREAM_CAPTURE)
        return &rt->capture;
    snd_printk(KERN_ERR PREFIX "error getting pcm substream slot.\n");
    return NULL;
}

/* call with stream_mutex locked */
static void usb6fire_pcm_stream_stop(struct pcm_runtime *rt)
{
    int i;
    struct control_runtime *ctrl_rt = rt->chip->control;

    if (rt->stream_state != STREAM_DISABLED) {
        for (i = 0; i < PCM_N_URBS; i++) {
            usb_kill_urb(&rt->in_urbs[i].instance);
            usb_kill_urb(&rt->out_urbs[i].instance);
        }
        ctrl_rt->usb_streaming = false;
        ctrl_rt->update_streaming(ctrl_rt);
        rt->stream_state = STREAM_DISABLED;
    }
}

/* call with stream_mutex locked */
static int usb6fire_pcm_stream_start(struct pcm_runtime *rt)
{
    int ret;
    int i;
    int k;
    struct usb_iso_packet_descriptor *packet;

    if (rt->stream_state == STREAM_DISABLED) {
        /* submit our in urbs */
        rt->stream_wait_cond = false;
        rt->stream_state = STREAM_STARTING;
        for (i = 0; i < PCM_N_URBS; i++) {
            for (k = 0; k < PCM_N_PACKETS_PER_URB; k++) {
                packet = &rt->in_urbs[i].packets[k];
                packet->offset = k * rt->in_packet_size;
                packet->length = rt->in_packet_size;
                packet->actual_length = 0;
                packet->status = 0;
            }
            ret = usb_submit_urb(&rt->in_urbs[i].instance,
                    GFP_ATOMIC);
            if (ret) {
                usb6fire_pcm_stream_stop(rt);
                return ret;
            }
        }

        /* wait for first out urb to return (sent in in urb handler) */
        wait_event_timeout(rt->stream_wait_queue, rt->stream_wait_cond,
                HZ);
        if (rt->stream_wait_cond)
            rt->stream_state = STREAM_RUNNING;
        else {
            usb6fire_pcm_stream_stop(rt);
            return -EIO;
        }
    }
    return 0;
}

/* call with substream locked */
static void usb6fire_pcm_capture(struct pcm_substream *sub, struct pcm_urb *urb)
{
    int i;
    int frame;
    int frame_count;
    unsigned int total_length = 0;
    struct pcm_runtime *rt = snd_pcm_substream_chip(sub->instance);
    struct snd_pcm_runtime *alsa_rt = sub->instance->runtime;
    u32 *src = NULL;
    u32 *dest = (u32 *) (alsa_rt->dma_area + sub->dma_off
            * (alsa_rt->frame_bits >> 3));
    u32 *dest_end = (u32 *) (alsa_rt->dma_area + alsa_rt->buffer_size
            * (alsa_rt->frame_bits >> 3));
    int bytes_per_frame = alsa_rt->channels << 2;

    for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
        /* at least 4 header bytes for valid packet.
         * after that: 32 bits per sample for analog channels */
        if (urb->packets[i].actual_length > 4)
            frame_count = (urb->packets[i].actual_length - 4)
                    / (rt->in_n_analog << 2);
        else
            frame_count = 0;

        if (alsa_rt->format == SNDRV_PCM_FORMAT_S24_LE)
            src = (u32 *) (urb->buffer + total_length);
        else if (alsa_rt->format == SNDRV_PCM_FORMAT_S32_LE)
            src = (u32 *) (urb->buffer - 1 + total_length);
        else
            return;
        src++; /* skip leading 4 bytes of every packet */
        total_length += urb->packets[i].length;
        for (frame = 0; frame < frame_count; frame++) {
            memcpy(dest, src, bytes_per_frame);
            dest += alsa_rt->channels;
            src += rt->in_n_analog;
            sub->dma_off++;
            sub->period_off++;
            if (dest == dest_end) {
                sub->dma_off = 0;
                dest = (u32 *) alsa_rt->dma_area;
            }
        }
    }
}

/* call with substream locked */
static void usb6fire_pcm_playback(struct pcm_substream *sub,
        struct pcm_urb *urb)
{
    int i;
    int frame;
    int frame_count;
    struct pcm_runtime *rt = snd_pcm_substream_chip(sub->instance);
    struct snd_pcm_runtime *alsa_rt = sub->instance->runtime;
    u32 *src = (u32 *) (alsa_rt->dma_area + sub->dma_off
            * (alsa_rt->frame_bits >> 3));
    u32 *src_end = (u32 *) (alsa_rt->dma_area + alsa_rt->buffer_size
            * (alsa_rt->frame_bits >> 3));
    u32 *dest;
    int bytes_per_frame = alsa_rt->channels << 2;

    if (alsa_rt->format == SNDRV_PCM_FORMAT_S32_LE)
        dest = (u32 *) (urb->buffer - 1);
    else if (alsa_rt->format == SNDRV_PCM_FORMAT_S24_LE)
        dest = (u32 *) (urb->buffer);
    else {
        snd_printk(KERN_ERR PREFIX "Unknown sample format.");
        return;
    }

    for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
        /* at least 4 header bytes for valid packet.
         * after that: 32 bits per sample for analog channels */
        if (urb->packets[i].length > 4)
            frame_count = (urb->packets[i].length - 4)
                    / (rt->out_n_analog << 2);
        else
            frame_count = 0;
        dest++; /* skip leading 4 bytes of every frame */
        for (frame = 0; frame < frame_count; frame++) {
            memcpy(dest, src, bytes_per_frame);
            src += alsa_rt->channels;
            dest += rt->out_n_analog;
            sub->dma_off++;
            sub->period_off++;
            if (src == src_end) {
                src = (u32 *) alsa_rt->dma_area;
                sub->dma_off = 0;
            }
        }
    }
}

static void usb6fire_pcm_in_urb_handler(struct urb *usb_urb)
{
    struct pcm_urb *in_urb = usb_urb->context;
    struct pcm_urb *out_urb = in_urb->peer;
    struct pcm_runtime *rt = in_urb->chip->pcm;
    struct pcm_substream *sub;
    unsigned long flags;
    int total_length = 0;
    int frame_count;
    int frame;
    int channel;
    int i;
    u8 *dest;

    if (usb_urb->status || rt->panic || rt->stream_state == STREAM_STOPPING)
        return;
    for (i = 0; i < PCM_N_PACKETS_PER_URB; i++)
        if (in_urb->packets[i].status) {
            rt->panic = true;
            return;
        }

    if (rt->stream_state == STREAM_DISABLED) {
        snd_printk(KERN_ERR PREFIX "internal error: "
                "stream disabled in in-urb handler.\n");
        return;
    }

    /* receive our capture data */
    sub = &rt->capture;
    spin_lock_irqsave(&sub->lock, flags);
    if (sub->active) {
        usb6fire_pcm_capture(sub, in_urb);
        if (sub->period_off >= sub->instance->runtime->period_size) {
            sub->period_off %= sub->instance->runtime->period_size;
            spin_unlock_irqrestore(&sub->lock, flags);
            snd_pcm_period_elapsed(sub->instance);
        } else
            spin_unlock_irqrestore(&sub->lock, flags);
    } else
        spin_unlock_irqrestore(&sub->lock, flags);

    /* setup out urb structure */
    for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
        out_urb->packets[i].offset = total_length;
        out_urb->packets[i].length = (in_urb->packets[i].actual_length
                - 4) / (rt->in_n_analog << 2)
                * (rt->out_n_analog << 2) + 4;
        out_urb->packets[i].status = 0;
        total_length += out_urb->packets[i].length;
    }
    memset(out_urb->buffer, 0, total_length);

    /* now send our playback data (if a free out urb was found) */
    sub = &rt->playback;
    spin_lock_irqsave(&sub->lock, flags);
    if (sub->active) {
        usb6fire_pcm_playback(sub, out_urb);
        if (sub->period_off >= sub->instance->runtime->period_size) {
            sub->period_off %= sub->instance->runtime->period_size;
            spin_unlock_irqrestore(&sub->lock, flags);
            snd_pcm_period_elapsed(sub->instance);
        } else
            spin_unlock_irqrestore(&sub->lock, flags);
    } else
        spin_unlock_irqrestore(&sub->lock, flags);

    /* setup the 4th byte of each sample (0x40 for analog channels) */
    dest = out_urb->buffer;
    for (i = 0; i < PCM_N_PACKETS_PER_URB; i++)
        if (out_urb->packets[i].length >= 4) {
            frame_count = (out_urb->packets[i].length - 4)
                    / (rt->out_n_analog << 2);
            *(dest++) = 0xaa;
            *(dest++) = 0xaa;
            *(dest++) = frame_count;
            *(dest++) = 0x00;
            for (frame = 0; frame < frame_count; frame++)
                for (channel = 0;
                        channel < rt->out_n_analog;
                        channel++) {
                    dest += 3; /* skip sample data */
                    *(dest++) = 0x40;
                }
        }
    usb_submit_urb(&out_urb->instance, GFP_ATOMIC);
    usb_submit_urb(&in_urb->instance, GFP_ATOMIC);
}

static void usb6fire_pcm_out_urb_handler(struct urb *usb_urb)
{
    struct pcm_urb *urb = usb_urb->context;
    struct pcm_runtime *rt = urb->chip->pcm;

    if (rt->stream_state == STREAM_STARTING) {
        rt->stream_wait_cond = true;
        wake_up(&rt->stream_wait_queue);
    }
}

static int usb6fire_pcm_open(struct snd_pcm_substream *alsa_sub)
{
    struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
    struct pcm_substream *sub = NULL;
    struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;

    if (rt->panic)
        return -EPIPE;

    mutex_lock(&rt->stream_mutex);
    alsa_rt->hw = pcm_hw;

    if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK) {
        if (rt->rate < ARRAY_SIZE(rates))
            alsa_rt->hw.rates = rates_alsaid[rt->rate];
        alsa_rt->hw.channels_max = OUT_N_CHANNELS;
        sub = &rt->playback;
    } else if (alsa_sub->stream == SNDRV_PCM_STREAM_CAPTURE) {
        if (rt->rate < ARRAY_SIZE(rates))
            alsa_rt->hw.rates = rates_alsaid[rt->rate];
        alsa_rt->hw.channels_max = IN_N_CHANNELS;
        sub = &rt->capture;
    }

    if (!sub) {
        mutex_unlock(&rt->stream_mutex);
        snd_printk(KERN_ERR PREFIX "invalid stream type.\n");
        return -EINVAL;
    }

    sub->instance = alsa_sub;
    sub->active = false;
    mutex_unlock(&rt->stream_mutex);
    return 0;
}

static int usb6fire_pcm_close(struct snd_pcm_substream *alsa_sub)
{
    struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
    struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
    unsigned long flags;

    if (rt->panic)
        return 0;

    mutex_lock(&rt->stream_mutex);
    if (sub) {
        /* deactivate substream */
        spin_lock_irqsave(&sub->lock, flags);
        sub->instance = NULL;
        sub->active = false;
        spin_unlock_irqrestore(&sub->lock, flags);

        /* all substreams closed? if so, stop streaming */
        if (!rt->playback.instance && !rt->capture.instance) {
            usb6fire_pcm_stream_stop(rt);
            rt->rate = ARRAY_SIZE(rates);
        }
    }
    mutex_unlock(&rt->stream_mutex);
    return 0;
}

static int usb6fire_pcm_hw_params(struct snd_pcm_substream *alsa_sub,
        struct snd_pcm_hw_params *hw_params)
{
    return snd_pcm_lib_malloc_pages(alsa_sub,
            params_buffer_bytes(hw_params));
}

static int usb6fire_pcm_hw_free(struct snd_pcm_substream *alsa_sub)
{
    return snd_pcm_lib_free_pages(alsa_sub);
}

static int usb6fire_pcm_prepare(struct snd_pcm_substream *alsa_sub)
{
    struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
    struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
    struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
    int ret;

    if (rt->panic)
        return -EPIPE;
    if (!sub)
        return -ENODEV;

    mutex_lock(&rt->stream_mutex);
    sub->dma_off = 0;
    sub->period_off = 0;

    if (rt->stream_state == STREAM_DISABLED) {
        for (rt->rate = 0; rt->rate < ARRAY_SIZE(rates); rt->rate++)
            if (alsa_rt->rate == rates[rt->rate])
                break;
        if (rt->rate == ARRAY_SIZE(rates)) {
            mutex_unlock(&rt->stream_mutex);
            snd_printk("invalid rate %d in prepare.\n",
                    alsa_rt->rate);
            return -EINVAL;
        }

        ret = usb6fire_pcm_set_rate(rt);
        if (ret) {
            mutex_unlock(&rt->stream_mutex);
            return ret;
        }
        ret = usb6fire_pcm_stream_start(rt);
        if (ret) {
            mutex_unlock(&rt->stream_mutex);
            snd_printk(KERN_ERR PREFIX
                    "could not start pcm stream.\n");
            return ret;
        }
    }
    mutex_unlock(&rt->stream_mutex);
    return 0;
}

static int usb6fire_pcm_trigger(struct snd_pcm_substream *alsa_sub, int cmd)
{
    struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
    struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
    unsigned long flags;

    if (rt->panic)
        return -EPIPE;
    if (!sub)
        return -ENODEV;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        spin_lock_irqsave(&sub->lock, flags);
        sub->active = true;
        spin_unlock_irqrestore(&sub->lock, flags);
        return 0;

    case SNDRV_PCM_TRIGGER_STOP:
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        spin_lock_irqsave(&sub->lock, flags);
        sub->active = false;
        spin_unlock_irqrestore(&sub->lock, flags);
        return 0;

    default:
        return -EINVAL;
    }
}

static snd_pcm_uframes_t usb6fire_pcm_pointer(
        struct snd_pcm_substream *alsa_sub)
{
    struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
    struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
    unsigned long flags;
    snd_pcm_uframes_t ret;

    if (rt->panic || !sub)
        return SNDRV_PCM_STATE_XRUN;

    spin_lock_irqsave(&sub->lock, flags);
    ret = sub->dma_off;
    spin_unlock_irqrestore(&sub->lock, flags);
    return ret;
}

static struct snd_pcm_ops pcm_ops = {
    .open = usb6fire_pcm_open,
    .close = usb6fire_pcm_close,
    .ioctl = snd_pcm_lib_ioctl,
    .hw_params = usb6fire_pcm_hw_params,
    .hw_free = usb6fire_pcm_hw_free,
    .prepare = usb6fire_pcm_prepare,
    .trigger = usb6fire_pcm_trigger,
    .pointer = usb6fire_pcm_pointer,
};

static void __devinit usb6fire_pcm_init_urb(struct pcm_urb *urb,
        struct sfire_chip *chip, bool in, int ep,
        void (*handler)(struct urb *))
{
    urb->chip = chip;
    usb_init_urb(&urb->instance);
    urb->instance.transfer_buffer = urb->buffer;
    urb->instance.transfer_buffer_length =
            PCM_N_PACKETS_PER_URB * PCM_MAX_PACKET_SIZE;
    urb->instance.dev = chip->dev;
    urb->instance.pipe = in ? usb_rcvisocpipe(chip->dev, ep)
            : usb_sndisocpipe(chip->dev, ep);
    urb->instance.interval = 1;
    urb->instance.transfer_flags = URB_ISO_ASAP;
    urb->instance.complete = handler;
    urb->instance.context = urb;
    urb->instance.number_of_packets = PCM_N_PACKETS_PER_URB;
}

int __devinit usb6fire_pcm_init(struct sfire_chip *chip)
{
    int i;
    int ret;
    struct snd_pcm *pcm;
    struct pcm_runtime *rt =
            kzalloc(sizeof(struct pcm_runtime), GFP_KERNEL);

    if (!rt)
        return -ENOMEM;

    rt->chip = chip;
    rt->stream_state = STREAM_DISABLED;
    rt->rate = ARRAY_SIZE(rates);
    init_waitqueue_head(&rt->stream_wait_queue);
    mutex_init(&rt->stream_mutex);

    spin_lock_init(&rt->playback.lock);
    spin_lock_init(&rt->capture.lock);

    for (i = 0; i < PCM_N_URBS; i++) {
        usb6fire_pcm_init_urb(&rt->in_urbs[i], chip, true, IN_EP,
                usb6fire_pcm_in_urb_handler);
        usb6fire_pcm_init_urb(&rt->out_urbs[i], chip, false, OUT_EP,
                usb6fire_pcm_out_urb_handler);

        rt->in_urbs[i].peer = &rt->out_urbs[i];
        rt->out_urbs[i].peer = &rt->in_urbs[i];
    }

    ret = snd_pcm_new(chip->card, "DMX6FireUSB", 0, 1, 1, &pcm);
    if (ret < 0) {
        kfree(rt);
        snd_printk(KERN_ERR PREFIX "cannot create pcm instance.\n");
        return ret;
    }

    pcm->private_data = rt;
    strcpy(pcm->name, "DMX 6Fire USB");
    snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_ops);
    snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &pcm_ops);

    ret = snd_pcm_lib_preallocate_pages_for_all(pcm,
            SNDRV_DMA_TYPE_CONTINUOUS,
            snd_dma_continuous_data(GFP_KERNEL),
            MAX_BUFSIZE, MAX_BUFSIZE);
    if (ret) {
        kfree(rt);
        snd_printk(KERN_ERR PREFIX
                "error preallocating pcm buffers.\n");
        return ret;
    }
    rt->instance = pcm;

    chip->pcm = rt;
    return 0;
}

void usb6fire_pcm_abort(struct sfire_chip *chip)
{
    struct pcm_runtime *rt = chip->pcm;
    int i;

    if (rt) {
        rt->panic = true;

        if (rt->playback.instance)
            snd_pcm_stop(rt->playback.instance,
                    SNDRV_PCM_STATE_XRUN);
        if (rt->capture.instance)
            snd_pcm_stop(rt->capture.instance,
                    SNDRV_PCM_STATE_XRUN);

        for (i = 0; i < PCM_N_URBS; i++) {
            usb_poison_urb(&rt->in_urbs[i].instance);
            usb_poison_urb(&rt->out_urbs[i].instance);
        }

    }
}

void usb6fire_pcm_destroy(struct sfire_chip *chip)
{
    kfree(chip->pcm);
    chip->pcm = NULL;
}