root/sound/usb/caiaq/audio.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (c) 2006-2008 Daniel Mack, Karsten Wiese
*/

#include <linux/device.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/usb.h>
#include <sound/core.h>
#include <sound/pcm.h>

#include "device.h"
#include "audio.h"

#define N_URBS                  32
#define CLOCK_DRIFT_TOLERANCE   5
#define FRAMES_PER_URB          8
#define BYTES_PER_FRAME         512
#define CHANNELS_PER_STREAM     2
#define BYTES_PER_SAMPLE        3
#define BYTES_PER_SAMPLE_USB    4
#define MAX_BUFFER_SIZE         (128*1024)
#define MAX_ENDPOINT_SIZE       512

#define ENDPOINT_CAPTURE        2
#define ENDPOINT_PLAYBACK       6

#define MAKE_CHECKBYTE(cdev,stream,i) \
        (stream << 1) | (~(i / (cdev->n_streams * BYTES_PER_SAMPLE_USB)) & 1)

static const struct snd_pcm_hardware snd_usb_caiaq_pcm_hardware = {
        .info           = (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
                           SNDRV_PCM_INFO_BLOCK_TRANSFER),
        .formats        = SNDRV_PCM_FMTBIT_S24_3BE,
        .rates          = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |
                           SNDRV_PCM_RATE_96000),
        .rate_min       = 44100,
        .rate_max       = 0, /* will overwrite later */
        .channels_min   = CHANNELS_PER_STREAM,
        .channels_max   = CHANNELS_PER_STREAM,
        .buffer_bytes_max = MAX_BUFFER_SIZE,
        .period_bytes_min = 128,
        .period_bytes_max = MAX_BUFFER_SIZE,
        .periods_min    = 1,
        .periods_max    = 1024,
};

static void
activate_substream(struct snd_usb_caiaqdev *cdev,
                   struct snd_pcm_substream *sub)
{
        guard(spinlock)(&cdev->spinlock);

        if (sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
                cdev->sub_playback[sub->number] = sub;
        else
                cdev->sub_capture[sub->number] = sub;
}

static void
deactivate_substream(struct snd_usb_caiaqdev *cdev,
                     struct snd_pcm_substream *sub)
{
        guard(spinlock_irqsave)(&cdev->spinlock);

        if (sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
                cdev->sub_playback[sub->number] = NULL;
        else
                cdev->sub_capture[sub->number] = NULL;
}

static int
all_substreams_zero(struct snd_pcm_substream **subs)
{
        int i;
        for (i = 0; i < MAX_STREAMS; i++)
                if (subs[i] != NULL)
                        return 0;
        return 1;
}

static int stream_start(struct snd_usb_caiaqdev *cdev)
{
        int i, ret;
        struct device *dev = caiaqdev_to_dev(cdev);

        dev_dbg(dev, "%s(%p)\n", __func__, cdev);

        if (cdev->streaming)
                return -EINVAL;

        memset(cdev->sub_playback, 0, sizeof(cdev->sub_playback));
        memset(cdev->sub_capture, 0, sizeof(cdev->sub_capture));
        cdev->input_panic = 0;
        cdev->output_panic = 0;
        cdev->first_packet = 4;
        cdev->streaming = 1;
        cdev->warned = 0;

        for (i = 0; i < N_URBS; i++) {
                ret = usb_submit_urb(cdev->data_urbs_in[i], GFP_ATOMIC);
                if (ret) {
                        dev_err(dev, "unable to trigger read #%d! (ret %d)\n",
                                i, ret);
                        cdev->streaming = 0;
                        return -EPIPE;
                }
        }

        return 0;
}

static void stream_stop(struct snd_usb_caiaqdev *cdev)
{
        int i;
        struct device *dev = caiaqdev_to_dev(cdev);

        dev_dbg(dev, "%s(%p)\n", __func__, cdev);
        if (!cdev->streaming)
                return;

        cdev->streaming = 0;

        for (i = 0; i < N_URBS; i++) {
                usb_kill_urb(cdev->data_urbs_in[i]);

                if (test_bit(i, &cdev->outurb_active_mask))
                        usb_kill_urb(cdev->data_urbs_out[i]);
        }

        cdev->outurb_active_mask = 0;
}

static int snd_usb_caiaq_substream_open(struct snd_pcm_substream *substream)
{
        struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(substream);
        struct device *dev = caiaqdev_to_dev(cdev);

        dev_dbg(dev, "%s(%p)\n", __func__, substream);
        substream->runtime->hw = cdev->pcm_info;
        snd_pcm_limit_hw_rates(substream->runtime);

        return 0;
}

static int snd_usb_caiaq_substream_close(struct snd_pcm_substream *substream)
{
        struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(substream);
        struct device *dev = caiaqdev_to_dev(cdev);

        dev_dbg(dev, "%s(%p)\n", __func__, substream);
        if (all_substreams_zero(cdev->sub_playback) &&
            all_substreams_zero(cdev->sub_capture)) {
                /* when the last client has stopped streaming,
                 * all sample rates are allowed again */
                stream_stop(cdev);
                cdev->pcm_info.rates = cdev->samplerates;
        }

        return 0;
}

static int snd_usb_caiaq_pcm_hw_free(struct snd_pcm_substream *sub)
{
        struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(sub);
        deactivate_substream(cdev, sub);
        return 0;
}

static int snd_usb_caiaq_pcm_prepare(struct snd_pcm_substream *substream)
{
        int bytes_per_sample, bpp, ret;
        int index = substream->number;
        struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct device *dev = caiaqdev_to_dev(cdev);

        dev_dbg(dev, "%s(%p)\n", __func__, substream);

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                int out_pos;

                switch (cdev->spec.data_alignment) {
                case 0:
                case 2:
                        out_pos = BYTES_PER_SAMPLE + 1;
                        break;
                case 3:
                default:
                        out_pos = 0;
                        break;
                }

                cdev->period_out_count[index] = out_pos;
                cdev->audio_out_buf_pos[index] = out_pos;
        } else {
                int in_pos;

                switch (cdev->spec.data_alignment) {
                case 0:
                        in_pos = BYTES_PER_SAMPLE + 2;
                        break;
                case 2:
                        in_pos = BYTES_PER_SAMPLE;
                        break;
                case 3:
                default:
                        in_pos = 0;
                        break;
                }

                cdev->period_in_count[index] = in_pos;
                cdev->audio_in_buf_pos[index] = in_pos;
        }

        if (cdev->streaming)
                return 0;

        /* the first client that opens a stream defines the sample rate
         * setting for all subsequent calls, until the last client closed. */
        cdev->pcm_info.rates = snd_pcm_rate_to_rate_bit(runtime->rate);
        snd_pcm_limit_hw_rates(runtime);

        bytes_per_sample = BYTES_PER_SAMPLE;
        if (cdev->spec.data_alignment >= 2)
                bytes_per_sample++;

        bpp = ((runtime->rate / 8000) + CLOCK_DRIFT_TOLERANCE)
                * bytes_per_sample * CHANNELS_PER_STREAM * cdev->n_streams;

        if (bpp > MAX_ENDPOINT_SIZE)
                bpp = MAX_ENDPOINT_SIZE;

        ret = snd_usb_caiaq_set_audio_params(cdev, runtime->rate,
                                             runtime->sample_bits, bpp);
        if (ret)
                return ret;

        ret = stream_start(cdev);
        if (ret)
                return ret;

        cdev->output_running = 0;
        wait_event_timeout(cdev->prepare_wait_queue, cdev->output_running, HZ);
        if (!cdev->output_running) {
                stream_stop(cdev);
                return -EPIPE;
        }

        return 0;
}

static int snd_usb_caiaq_pcm_trigger(struct snd_pcm_substream *sub, int cmd)
{
        struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(sub);
        struct device *dev = caiaqdev_to_dev(cdev);

        dev_dbg(dev, "%s(%p) cmd %d\n", __func__, sub, cmd);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                activate_substream(cdev, sub);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                deactivate_substream(cdev, sub);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static snd_pcm_uframes_t
snd_usb_caiaq_pcm_pointer(struct snd_pcm_substream *sub)
{
        int index = sub->number;
        struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(sub);

        guard(spinlock)(&cdev->spinlock);

        if (cdev->input_panic || cdev->output_panic)
                return SNDRV_PCM_POS_XRUN;

        if (sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
                return bytes_to_frames(sub->runtime,
                                       cdev->audio_out_buf_pos[index]);
        else
                return bytes_to_frames(sub->runtime,
                                       cdev->audio_in_buf_pos[index]);
}

/* operators for both playback and capture */
static const struct snd_pcm_ops snd_usb_caiaq_ops = {
        .open =         snd_usb_caiaq_substream_open,
        .close =        snd_usb_caiaq_substream_close,
        .hw_free =      snd_usb_caiaq_pcm_hw_free,
        .prepare =      snd_usb_caiaq_pcm_prepare,
        .trigger =      snd_usb_caiaq_pcm_trigger,
        .pointer =      snd_usb_caiaq_pcm_pointer,
};

static void check_for_elapsed_periods(struct snd_usb_caiaqdev *cdev,
                                      struct snd_pcm_substream **subs)
{
        int stream, pb, *cnt;
        struct snd_pcm_substream *sub;

        for (stream = 0; stream < cdev->n_streams; stream++) {
                sub = subs[stream];
                if (!sub)
                        continue;

                pb = snd_pcm_lib_period_bytes(sub);
                cnt = (sub->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
                                        &cdev->period_out_count[stream] :
                                        &cdev->period_in_count[stream];

                if (*cnt >= pb) {
                        snd_pcm_period_elapsed(sub);
                        *cnt %= pb;
                }
        }
}

static void read_in_urb_mode0(struct snd_usb_caiaqdev *cdev,
                              const struct urb *urb,
                              const struct usb_iso_packet_descriptor *iso)
{
        unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
        struct snd_pcm_substream *sub;
        int stream, i;

        if (all_substreams_zero(cdev->sub_capture))
                return;

        for (i = 0; i < iso->actual_length;) {
                for (stream = 0; stream < cdev->n_streams; stream++, i++) {
                        sub = cdev->sub_capture[stream];
                        if (sub) {
                                struct snd_pcm_runtime *rt = sub->runtime;
                                char *audio_buf = rt->dma_area;
                                int sz = frames_to_bytes(rt, rt->buffer_size);
                                audio_buf[cdev->audio_in_buf_pos[stream]++]
                                        = usb_buf[i];
                                cdev->period_in_count[stream]++;
                                if (cdev->audio_in_buf_pos[stream] == sz)
                                        cdev->audio_in_buf_pos[stream] = 0;
                        }
                }
        }
}

static void read_in_urb_mode2(struct snd_usb_caiaqdev *cdev,
                              const struct urb *urb,
                              const struct usb_iso_packet_descriptor *iso)
{
        unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
        unsigned char check_byte;
        struct snd_pcm_substream *sub;
        int stream, i;

        for (i = 0; i < iso->actual_length;) {
                if (i % (cdev->n_streams * BYTES_PER_SAMPLE_USB) == 0) {
                        for (stream = 0;
                             stream < cdev->n_streams;
                             stream++, i++) {
                                if (cdev->first_packet)
                                        continue;

                                check_byte = MAKE_CHECKBYTE(cdev, stream, i);

                                if ((usb_buf[i] & 0x3f) != check_byte)
                                        cdev->input_panic = 1;

                                if (usb_buf[i] & 0x80)
                                        cdev->output_panic = 1;
                        }
                }
                cdev->first_packet = 0;

                for (stream = 0; stream < cdev->n_streams; stream++, i++) {
                        sub = cdev->sub_capture[stream];
                        if (cdev->input_panic)
                                usb_buf[i] = 0;

                        if (sub) {
                                struct snd_pcm_runtime *rt = sub->runtime;
                                char *audio_buf = rt->dma_area;
                                int sz = frames_to_bytes(rt, rt->buffer_size);
                                audio_buf[cdev->audio_in_buf_pos[stream]++] =
                                        usb_buf[i];
                                cdev->period_in_count[stream]++;
                                if (cdev->audio_in_buf_pos[stream] == sz)
                                        cdev->audio_in_buf_pos[stream] = 0;
                        }
                }
        }
}

static void read_in_urb_mode3(struct snd_usb_caiaqdev *cdev,
                              const struct urb *urb,
                              const struct usb_iso_packet_descriptor *iso)
{
        unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
        struct device *dev = caiaqdev_to_dev(cdev);
        int stream, i;

        /* paranoia check */
        if (iso->actual_length % (BYTES_PER_SAMPLE_USB * CHANNELS_PER_STREAM))
                return;

        for (i = 0; i < iso->actual_length;) {
                for (stream = 0; stream < cdev->n_streams; stream++) {
                        struct snd_pcm_substream *sub = cdev->sub_capture[stream];
                        char *audio_buf = NULL;
                        int c, n, sz = 0;

                        if (sub && !cdev->input_panic) {
                                struct snd_pcm_runtime *rt = sub->runtime;
                                audio_buf = rt->dma_area;
                                sz = frames_to_bytes(rt, rt->buffer_size);
                        }

                        for (c = 0; c < CHANNELS_PER_STREAM; c++) {
                                /* 3 audio data bytes, followed by 1 check byte */
                                if (audio_buf) {
                                        for (n = 0; n < BYTES_PER_SAMPLE; n++) {
                                                audio_buf[cdev->audio_in_buf_pos[stream]++] = usb_buf[i+n];

                                                if (cdev->audio_in_buf_pos[stream] == sz)
                                                        cdev->audio_in_buf_pos[stream] = 0;
                                        }

                                        cdev->period_in_count[stream] += BYTES_PER_SAMPLE;
                                }

                                i += BYTES_PER_SAMPLE;

                                if (usb_buf[i] != ((stream << 1) | c) &&
                                    !cdev->first_packet) {
                                        if (!cdev->input_panic)
                                                dev_warn(dev, " EXPECTED: %02x got %02x, c %d, stream %d, i %d\n",
                                                         ((stream << 1) | c), usb_buf[i], c, stream, i);
                                        cdev->input_panic = 1;
                                }

                                i++;
                        }
                }
        }

        if (cdev->first_packet > 0)
                cdev->first_packet--;
}

static void read_in_urb(struct snd_usb_caiaqdev *cdev,
                        const struct urb *urb,
                        const struct usb_iso_packet_descriptor *iso)
{
        struct device *dev = caiaqdev_to_dev(cdev);

        if (!cdev->streaming)
                return;

        if (iso->actual_length < cdev->bpp)
                return;

        switch (cdev->spec.data_alignment) {
        case 0:
                read_in_urb_mode0(cdev, urb, iso);
                break;
        case 2:
                read_in_urb_mode2(cdev, urb, iso);
                break;
        case 3:
                read_in_urb_mode3(cdev, urb, iso);
                break;
        }

        if ((cdev->input_panic || cdev->output_panic) && !cdev->warned) {
                dev_warn(dev, "streaming error detected %s %s\n",
                                cdev->input_panic ? "(input)" : "",
                                cdev->output_panic ? "(output)" : "");
                cdev->warned = 1;
        }
}

static void fill_out_urb_mode_0(struct snd_usb_caiaqdev *cdev,
                                struct urb *urb,
                                const struct usb_iso_packet_descriptor *iso)
{
        unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
        struct snd_pcm_substream *sub;
        int stream, i;

        for (i = 0; i < iso->length;) {
                for (stream = 0; stream < cdev->n_streams; stream++, i++) {
                        sub = cdev->sub_playback[stream];
                        if (sub) {
                                struct snd_pcm_runtime *rt = sub->runtime;
                                char *audio_buf = rt->dma_area;
                                int sz = frames_to_bytes(rt, rt->buffer_size);
                                usb_buf[i] =
                                        audio_buf[cdev->audio_out_buf_pos[stream]];
                                cdev->period_out_count[stream]++;
                                cdev->audio_out_buf_pos[stream]++;
                                if (cdev->audio_out_buf_pos[stream] == sz)
                                        cdev->audio_out_buf_pos[stream] = 0;
                        } else
                                usb_buf[i] = 0;
                }

                /* fill in the check bytes */
                if (cdev->spec.data_alignment == 2 &&
                    i % (cdev->n_streams * BYTES_PER_SAMPLE_USB) ==
                        (cdev->n_streams * CHANNELS_PER_STREAM))
                        for (stream = 0; stream < cdev->n_streams; stream++, i++)
                                usb_buf[i] = MAKE_CHECKBYTE(cdev, stream, i);
        }
}

static void fill_out_urb_mode_3(struct snd_usb_caiaqdev *cdev,
                                struct urb *urb,
                                const struct usb_iso_packet_descriptor *iso)
{
        unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
        int stream, i;

        for (i = 0; i < iso->length;) {
                for (stream = 0; stream < cdev->n_streams; stream++) {
                        struct snd_pcm_substream *sub = cdev->sub_playback[stream];
                        char *audio_buf = NULL;
                        int c, n, sz = 0;

                        if (sub) {
                                struct snd_pcm_runtime *rt = sub->runtime;
                                audio_buf = rt->dma_area;
                                sz = frames_to_bytes(rt, rt->buffer_size);
                        }

                        for (c = 0; c < CHANNELS_PER_STREAM; c++) {
                                for (n = 0; n < BYTES_PER_SAMPLE; n++) {
                                        if (audio_buf) {
                                                usb_buf[i+n] = audio_buf[cdev->audio_out_buf_pos[stream]++];

                                                if (cdev->audio_out_buf_pos[stream] == sz)
                                                        cdev->audio_out_buf_pos[stream] = 0;
                                        } else {
                                                usb_buf[i+n] = 0;
                                        }
                                }

                                if (audio_buf)
                                        cdev->period_out_count[stream] += BYTES_PER_SAMPLE;

                                i += BYTES_PER_SAMPLE;

                                /* fill in the check byte pattern */
                                usb_buf[i++] = (stream << 1) | c;
                        }
                }
        }
}

static inline void fill_out_urb(struct snd_usb_caiaqdev *cdev,
                                struct urb *urb,
                                const struct usb_iso_packet_descriptor *iso)
{
        switch (cdev->spec.data_alignment) {
        case 0:
        case 2:
                fill_out_urb_mode_0(cdev, urb, iso);
                break;
        case 3:
                fill_out_urb_mode_3(cdev, urb, iso);
                break;
        }
}

static void read_completed(struct urb *urb)
{
        struct snd_usb_caiaq_cb_info *info = urb->context;
        struct snd_usb_caiaqdev *cdev;
        struct device *dev;
        struct urb *out = NULL;
        int i, frame, len, send_it = 0, outframe = 0;
        size_t offset = 0;

        if (urb->status || !info)
                return;

        cdev = info->cdev;
        dev = caiaqdev_to_dev(cdev);

        if (!cdev->streaming)
                return;

        /* find an unused output urb that is unused */
        for (i = 0; i < N_URBS; i++)
                if (test_and_set_bit(i, &cdev->outurb_active_mask) == 0) {
                        out = cdev->data_urbs_out[i];
                        break;
                }

        if (!out) {
                dev_err(dev, "Unable to find an output urb to use\n");
                goto requeue;
        }

        /* read the recently received packet and send back one which has
         * the same layout */
        for (frame = 0; frame < FRAMES_PER_URB; frame++) {
                if (urb->iso_frame_desc[frame].status)
                        continue;

                len = urb->iso_frame_desc[outframe].actual_length;
                out->iso_frame_desc[outframe].length = len;
                out->iso_frame_desc[outframe].actual_length = 0;
                out->iso_frame_desc[outframe].offset = offset;
                offset += len;

                if (len > 0) {
                        scoped_guard(spinlock_irqsave, &cdev->spinlock) {
                                fill_out_urb(cdev, out, &out->iso_frame_desc[outframe]);
                                read_in_urb(cdev, urb, &urb->iso_frame_desc[frame]);
                        }
                        check_for_elapsed_periods(cdev, cdev->sub_playback);
                        check_for_elapsed_periods(cdev, cdev->sub_capture);
                        send_it = 1;
                }

                outframe++;
        }

        if (send_it) {
                out->number_of_packets = outframe;
                usb_submit_urb(out, GFP_ATOMIC);
        } else {
                struct snd_usb_caiaq_cb_info *oinfo = out->context;
                clear_bit(oinfo->index, &cdev->outurb_active_mask);
        }

requeue:
        /* re-submit inbound urb */
        for (frame = 0; frame < FRAMES_PER_URB; frame++) {
                urb->iso_frame_desc[frame].offset = BYTES_PER_FRAME * frame;
                urb->iso_frame_desc[frame].length = BYTES_PER_FRAME;
                urb->iso_frame_desc[frame].actual_length = 0;
        }

        urb->number_of_packets = FRAMES_PER_URB;
        usb_submit_urb(urb, GFP_ATOMIC);
}

static void write_completed(struct urb *urb)
{
        struct snd_usb_caiaq_cb_info *info = urb->context;
        struct snd_usb_caiaqdev *cdev = info->cdev;

        if (!cdev->output_running) {
                cdev->output_running = 1;
                wake_up(&cdev->prepare_wait_queue);
        }

        clear_bit(info->index, &cdev->outurb_active_mask);
}

static struct urb **alloc_urbs(struct snd_usb_caiaqdev *cdev, int dir, int *ret)
{
        int i, frame;
        struct urb **urbs;
        struct usb_device *usb_dev = cdev->chip.dev;
        unsigned int pipe;

        pipe = (dir == SNDRV_PCM_STREAM_PLAYBACK) ?
                usb_sndisocpipe(usb_dev, ENDPOINT_PLAYBACK) :
                usb_rcvisocpipe(usb_dev, ENDPOINT_CAPTURE);

        urbs = kmalloc_objs(*urbs, N_URBS);
        if (!urbs) {
                *ret = -ENOMEM;
                return NULL;
        }

        for (i = 0; i < N_URBS; i++) {
                urbs[i] = usb_alloc_urb(FRAMES_PER_URB, GFP_KERNEL);
                if (!urbs[i]) {
                        *ret = -ENOMEM;
                        return urbs;
                }

                urbs[i]->transfer_buffer =
                        kmalloc_array(BYTES_PER_FRAME, FRAMES_PER_URB,
                                      GFP_KERNEL);
                if (!urbs[i]->transfer_buffer) {
                        *ret = -ENOMEM;
                        return urbs;
                }

                for (frame = 0; frame < FRAMES_PER_URB; frame++) {
                        struct usb_iso_packet_descriptor *iso =
                                &urbs[i]->iso_frame_desc[frame];

                        iso->offset = BYTES_PER_FRAME * frame;
                        iso->length = BYTES_PER_FRAME;
                }

                urbs[i]->dev = usb_dev;
                urbs[i]->pipe = pipe;
                urbs[i]->transfer_buffer_length = FRAMES_PER_URB
                                                * BYTES_PER_FRAME;
                urbs[i]->context = &cdev->data_cb_info[i];
                urbs[i]->interval = 1;
                urbs[i]->number_of_packets = FRAMES_PER_URB;
                urbs[i]->complete = (dir == SNDRV_PCM_STREAM_CAPTURE) ?
                                        read_completed : write_completed;
        }

        *ret = 0;
        return urbs;
}

static void free_urbs(struct urb **urbs)
{
        int i;

        if (!urbs)
                return;

        for (i = 0; i < N_URBS; i++) {
                if (!urbs[i])
                        continue;

                usb_kill_urb(urbs[i]);
                kfree(urbs[i]->transfer_buffer);
                usb_free_urb(urbs[i]);
        }

        kfree(urbs);
}

int snd_usb_caiaq_audio_init(struct snd_usb_caiaqdev *cdev)
{
        int i, ret;
        struct device *dev = caiaqdev_to_dev(cdev);

        cdev->n_audio_in  = max(cdev->spec.num_analog_audio_in,
                               cdev->spec.num_digital_audio_in) /
                                CHANNELS_PER_STREAM;
        cdev->n_audio_out = max(cdev->spec.num_analog_audio_out,
                               cdev->spec.num_digital_audio_out) /
                                CHANNELS_PER_STREAM;
        cdev->n_streams = max(cdev->n_audio_in, cdev->n_audio_out);

        dev_dbg(dev, "cdev->n_audio_in = %d\n", cdev->n_audio_in);
        dev_dbg(dev, "cdev->n_audio_out = %d\n", cdev->n_audio_out);
        dev_dbg(dev, "cdev->n_streams = %d\n", cdev->n_streams);

        if (cdev->n_streams > MAX_STREAMS) {
                dev_err(dev, "unable to initialize device, too many streams.\n");
                return -EINVAL;
        }

        if (cdev->n_streams < 1) {
                dev_err(dev, "bogus number of streams: %d\n", cdev->n_streams);
                return -EINVAL;
        }

        ret = snd_pcm_new(cdev->chip.card, cdev->product_name, 0,
                        cdev->n_audio_out, cdev->n_audio_in, &cdev->pcm);

        if (ret < 0) {
                dev_err(dev, "snd_pcm_new() returned %d\n", ret);
                return ret;
        }

        cdev->pcm->private_data = cdev;
        strscpy(cdev->pcm->name, cdev->product_name, sizeof(cdev->pcm->name));

        memset(cdev->sub_playback, 0, sizeof(cdev->sub_playback));
        memset(cdev->sub_capture, 0, sizeof(cdev->sub_capture));

        memcpy(&cdev->pcm_info, &snd_usb_caiaq_pcm_hardware,
                        sizeof(snd_usb_caiaq_pcm_hardware));

        /* setup samplerates */
        cdev->samplerates = cdev->pcm_info.rates;
        switch (cdev->chip.usb_id) {
        case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AK1):
        case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL3):
        case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_SESSIONIO):
        case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_GUITARRIGMOBILE):
                cdev->samplerates |= SNDRV_PCM_RATE_192000;
                fallthrough;
        case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO2DJ):
        case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO4DJ):
        case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO8DJ):
        case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORAUDIO2):
                cdev->samplerates |= SNDRV_PCM_RATE_88200;
                break;
        }

        snd_pcm_set_ops(cdev->pcm, SNDRV_PCM_STREAM_PLAYBACK,
                                &snd_usb_caiaq_ops);
        snd_pcm_set_ops(cdev->pcm, SNDRV_PCM_STREAM_CAPTURE,
                                &snd_usb_caiaq_ops);
        snd_pcm_set_managed_buffer_all(cdev->pcm, SNDRV_DMA_TYPE_VMALLOC,
                                       NULL, 0, 0);

        cdev->data_cb_info =
                kmalloc_objs(struct snd_usb_caiaq_cb_info, N_URBS);

        if (!cdev->data_cb_info)
                return -ENOMEM;

        cdev->outurb_active_mask = 0;
        BUILD_BUG_ON(N_URBS > (sizeof(cdev->outurb_active_mask) * 8));

        for (i = 0; i < N_URBS; i++) {
                cdev->data_cb_info[i].cdev = cdev;
                cdev->data_cb_info[i].index = i;
        }

        cdev->data_urbs_in = alloc_urbs(cdev, SNDRV_PCM_STREAM_CAPTURE, &ret);
        if (ret < 0) {
                kfree(cdev->data_cb_info);
                free_urbs(cdev->data_urbs_in);
                return ret;
        }

        cdev->data_urbs_out = alloc_urbs(cdev, SNDRV_PCM_STREAM_PLAYBACK, &ret);
        if (ret < 0) {
                kfree(cdev->data_cb_info);
                free_urbs(cdev->data_urbs_in);
                free_urbs(cdev->data_urbs_out);
                return ret;
        }

        return 0;
}

void snd_usb_caiaq_audio_disconnect(struct snd_usb_caiaqdev *cdev)
{
        struct device *dev = caiaqdev_to_dev(cdev);

        dev_dbg(dev, "%s(%p)\n", __func__, cdev);
        stream_stop(cdev);
}

void snd_usb_caiaq_audio_free(struct snd_usb_caiaqdev *cdev)
{
        struct device *dev = caiaqdev_to_dev(cdev);

        dev_dbg(dev, "%s(%p)\n", __func__, cdev);
        free_urbs(cdev->data_urbs_in);
        free_urbs(cdev->data_urbs_out);
        kfree(cdev->data_cb_info);
}