// SPDX-License-Identifier: GPL-2.0 OR MIT

/*
 * Xen para-virtual sound device
 *
 * Copyright (C) 2016-2018 EPAM Systems Inc.
 *
 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
 */

#include <linux/platform_device.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>

#include <xen/xenbus.h>
#include <xen/xen-front-pgdir-shbuf.h>

#include "xen_snd_front.h"
#include "xen_snd_front_alsa.h"
#include "xen_snd_front_cfg.h"
#include "xen_snd_front_evtchnl.h"

struct xen_snd_front_pcm_stream_info {
        struct xen_snd_front_info *front_info;
        struct xen_snd_front_evtchnl_pair *evt_pair;

        /* This is the shared buffer with its backing storage. */
        struct xen_front_pgdir_shbuf shbuf;
        u8 *buffer;
        size_t buffer_sz;
        int num_pages;
        struct page **pages;

        int index;

        bool is_open;
        struct snd_pcm_hardware pcm_hw;

        /* Number of processed frames as reported by the backend. */
        snd_pcm_uframes_t be_cur_frame;
        /* Current HW pointer to be reported via .period callback. */
        atomic_t hw_ptr;
        /* Modulo of the number of processed frames - for period detection. */
        u32 out_frames;
};

struct xen_snd_front_pcm_instance_info {
        struct xen_snd_front_card_info *card_info;
        struct snd_pcm *pcm;
        struct snd_pcm_hardware pcm_hw;
        int num_pcm_streams_pb;
        struct xen_snd_front_pcm_stream_info *streams_pb;
        int num_pcm_streams_cap;
        struct xen_snd_front_pcm_stream_info *streams_cap;
};

struct xen_snd_front_card_info {
        struct xen_snd_front_info *front_info;
        struct snd_card *card;
        struct snd_pcm_hardware pcm_hw;
        int num_pcm_instances;
        struct xen_snd_front_pcm_instance_info *pcm_instances;
};

struct alsa_sndif_sample_format {
        u8 sndif;
        snd_pcm_format_t alsa;
};

static const struct alsa_sndif_sample_format ALSA_SNDIF_FORMATS[] = {
        {
                .sndif = XENSND_PCM_FORMAT_U8,
                .alsa = SNDRV_PCM_FORMAT_U8
        },
        {
                .sndif = XENSND_PCM_FORMAT_S8,
                .alsa = SNDRV_PCM_FORMAT_S8
        },
        {
                .sndif = XENSND_PCM_FORMAT_U16_LE,
                .alsa = SNDRV_PCM_FORMAT_U16_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_U16_BE,
                .alsa = SNDRV_PCM_FORMAT_U16_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_S16_LE,
                .alsa = SNDRV_PCM_FORMAT_S16_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_S16_BE,
                .alsa = SNDRV_PCM_FORMAT_S16_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_U24_LE,
                .alsa = SNDRV_PCM_FORMAT_U24_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_U24_BE,
                .alsa = SNDRV_PCM_FORMAT_U24_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_S24_LE,
                .alsa = SNDRV_PCM_FORMAT_S24_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_S24_BE,
                .alsa = SNDRV_PCM_FORMAT_S24_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_U32_LE,
                .alsa = SNDRV_PCM_FORMAT_U32_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_U32_BE,
                .alsa = SNDRV_PCM_FORMAT_U32_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_S32_LE,
                .alsa = SNDRV_PCM_FORMAT_S32_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_S32_BE,
                .alsa = SNDRV_PCM_FORMAT_S32_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_A_LAW,
                .alsa = SNDRV_PCM_FORMAT_A_LAW
        },
        {
                .sndif = XENSND_PCM_FORMAT_MU_LAW,
                .alsa = SNDRV_PCM_FORMAT_MU_LAW
        },
        {
                .sndif = XENSND_PCM_FORMAT_F32_LE,
                .alsa = SNDRV_PCM_FORMAT_FLOAT_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_F32_BE,
                .alsa = SNDRV_PCM_FORMAT_FLOAT_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_F64_LE,
                .alsa = SNDRV_PCM_FORMAT_FLOAT64_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_F64_BE,
                .alsa = SNDRV_PCM_FORMAT_FLOAT64_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE,
                .alsa = SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE
        },
        {
                .sndif = XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE,
                .alsa = SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE
        },
        {
                .sndif = XENSND_PCM_FORMAT_IMA_ADPCM,
                .alsa = SNDRV_PCM_FORMAT_IMA_ADPCM
        },
        {
                .sndif = XENSND_PCM_FORMAT_MPEG,
                .alsa = SNDRV_PCM_FORMAT_MPEG
        },
        {
                .sndif = XENSND_PCM_FORMAT_GSM,
                .alsa = SNDRV_PCM_FORMAT_GSM
        },
};

static int to_sndif_format(snd_pcm_format_t format)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(ALSA_SNDIF_FORMATS); i++)
                if (ALSA_SNDIF_FORMATS[i].alsa == format)
                        return ALSA_SNDIF_FORMATS[i].sndif;

        return -EINVAL;
}

static u64 to_sndif_formats_mask(u64 alsa_formats)
{
        u64 mask;
        int i;

        mask = 0;
        for (i = 0; i < ARRAY_SIZE(ALSA_SNDIF_FORMATS); i++)
                if (pcm_format_to_bits(ALSA_SNDIF_FORMATS[i].alsa) & alsa_formats)
                        mask |= BIT_ULL(ALSA_SNDIF_FORMATS[i].sndif);

        return mask;
}

static u64 to_alsa_formats_mask(u64 sndif_formats)
{
        u64 mask;
        int i;

        mask = 0;
        for (i = 0; i < ARRAY_SIZE(ALSA_SNDIF_FORMATS); i++)
                if (BIT_ULL(ALSA_SNDIF_FORMATS[i].sndif) & sndif_formats)
                        mask |= pcm_format_to_bits(ALSA_SNDIF_FORMATS[i].alsa);

        return mask;
}

static void stream_clear(struct xen_snd_front_pcm_stream_info *stream)
{
        stream->is_open = false;
        stream->be_cur_frame = 0;
        stream->out_frames = 0;
        atomic_set(&stream->hw_ptr, 0);
        xen_snd_front_evtchnl_pair_clear(stream->evt_pair);
        memset(&stream->shbuf, 0, sizeof(stream->shbuf));
        stream->buffer = NULL;
        stream->buffer_sz = 0;
        stream->pages = NULL;
        stream->num_pages = 0;
}

static void stream_free(struct xen_snd_front_pcm_stream_info *stream)
{
        xen_front_pgdir_shbuf_unmap(&stream->shbuf);
        xen_front_pgdir_shbuf_free(&stream->shbuf);
        if (stream->buffer)
                free_pages_exact(stream->buffer, stream->buffer_sz);
        kfree(stream->pages);
        stream_clear(stream);
}

static struct xen_snd_front_pcm_stream_info *
stream_get(struct snd_pcm_substream *substream)
{
        struct xen_snd_front_pcm_instance_info *pcm_instance =
                        snd_pcm_substream_chip(substream);
        struct xen_snd_front_pcm_stream_info *stream;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                stream = &pcm_instance->streams_pb[substream->number];
        else
                stream = &pcm_instance->streams_cap[substream->number];

        return stream;
}

static int alsa_hw_rule(struct snd_pcm_hw_params *params,
                        struct snd_pcm_hw_rule *rule)
{
        struct xen_snd_front_pcm_stream_info *stream = rule->private;
        struct device *dev = &stream->front_info->xb_dev->dev;
        struct snd_mask *formats =
                        hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
        struct snd_interval *rates =
                        hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
        struct snd_interval *channels =
                        hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
        struct snd_interval *period =
                        hw_param_interval(params,
                                          SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
        struct snd_interval *buffer =
                        hw_param_interval(params,
                                          SNDRV_PCM_HW_PARAM_BUFFER_SIZE);
        struct xensnd_query_hw_param req;
        struct xensnd_query_hw_param resp;
        struct snd_interval interval;
        struct snd_mask mask;
        u64 sndif_formats;
        int changed, ret;

        /* Collect all the values we need for the query. */

        req.formats = to_sndif_formats_mask((u64)formats->bits[0] |
                                            (u64)(formats->bits[1]) << 32);

        req.rates.min = rates->min;
        req.rates.max = rates->max;

        req.channels.min = channels->min;
        req.channels.max = channels->max;

        req.buffer.min = buffer->min;
        req.buffer.max = buffer->max;

        req.period.min = period->min;
        req.period.max = period->max;

        ret = xen_snd_front_stream_query_hw_param(&stream->evt_pair->req,
                                                  &req, &resp);
        if (ret < 0) {
                /* Check if this is due to backend communication error. */
                if (ret == -EIO || ret == -ETIMEDOUT)
                        dev_err(dev, "Failed to query ALSA HW parameters\n");
                return ret;
        }

        /* Refine HW parameters after the query. */
        changed  = 0;

        sndif_formats = to_alsa_formats_mask(resp.formats);
        snd_mask_none(&mask);
        mask.bits[0] = (u32)sndif_formats;
        mask.bits[1] = (u32)(sndif_formats >> 32);
        ret = snd_mask_refine(formats, &mask);
        if (ret < 0)
                return ret;
        changed |= ret;

        interval.openmin = 0;
        interval.openmax = 0;
        interval.integer = 1;

        interval.min = resp.rates.min;
        interval.max = resp.rates.max;
        ret = snd_interval_refine(rates, &interval);
        if (ret < 0)
                return ret;
        changed |= ret;

        interval.min = resp.channels.min;
        interval.max = resp.channels.max;
        ret = snd_interval_refine(channels, &interval);
        if (ret < 0)
                return ret;
        changed |= ret;

        interval.min = resp.buffer.min;
        interval.max = resp.buffer.max;
        ret = snd_interval_refine(buffer, &interval);
        if (ret < 0)
                return ret;
        changed |= ret;

        interval.min = resp.period.min;
        interval.max = resp.period.max;
        ret = snd_interval_refine(period, &interval);
        if (ret < 0)
                return ret;
        changed |= ret;

        return changed;
}

static int alsa_open(struct snd_pcm_substream *substream)
{
        struct xen_snd_front_pcm_instance_info *pcm_instance =
                        snd_pcm_substream_chip(substream);
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct xen_snd_front_info *front_info =
                        pcm_instance->card_info->front_info;
        struct device *dev = &front_info->xb_dev->dev;
        int ret;

        /*
         * Return our HW properties: override defaults with those configured
         * via XenStore.
         */
        runtime->hw = stream->pcm_hw;
        runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
                              SNDRV_PCM_INFO_MMAP_VALID |
                              SNDRV_PCM_INFO_DOUBLE |
                              SNDRV_PCM_INFO_BATCH |
                              SNDRV_PCM_INFO_NONINTERLEAVED |
                              SNDRV_PCM_INFO_RESUME |
                              SNDRV_PCM_INFO_PAUSE);
        runtime->hw.info |= SNDRV_PCM_INFO_INTERLEAVED;

        stream->evt_pair = &front_info->evt_pairs[stream->index];

        stream->front_info = front_info;

        stream->evt_pair->evt.u.evt.substream = substream;

        stream_clear(stream);

        xen_snd_front_evtchnl_set_connected(&stream->evt_pair->req, true);

        ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
                                  alsa_hw_rule, stream,
                                  SNDRV_PCM_HW_PARAM_FORMAT, -1);
        if (ret) {
                dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_FORMAT\n");
                return ret;
        }

        ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
                                  alsa_hw_rule, stream,
                                  SNDRV_PCM_HW_PARAM_RATE, -1);
        if (ret) {
                dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_RATE\n");
                return ret;
        }

        ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
                                  alsa_hw_rule, stream,
                                  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
        if (ret) {
                dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_CHANNELS\n");
                return ret;
        }

        ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
                                  alsa_hw_rule, stream,
                                  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
        if (ret) {
                dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_PERIOD_SIZE\n");
                return ret;
        }

        ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
                                  alsa_hw_rule, stream,
                                  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, -1);
        if (ret) {
                dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_BUFFER_SIZE\n");
                return ret;
        }

        return 0;
}

static int alsa_close(struct snd_pcm_substream *substream)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);

        xen_snd_front_evtchnl_pair_set_connected(stream->evt_pair, false);
        return 0;
}

static int shbuf_setup_backstore(struct xen_snd_front_pcm_stream_info *stream,
                                 size_t buffer_sz)
{
        int i;

        stream->buffer = alloc_pages_exact(buffer_sz, GFP_KERNEL);
        if (!stream->buffer)
                return -ENOMEM;

        stream->buffer_sz = buffer_sz;
        stream->num_pages = DIV_ROUND_UP(stream->buffer_sz, PAGE_SIZE);
        stream->pages = kzalloc_objs(struct page *, stream->num_pages);
        if (!stream->pages)
                return -ENOMEM;

        for (i = 0; i < stream->num_pages; i++)
                stream->pages[i] = virt_to_page(stream->buffer + i * PAGE_SIZE);

        return 0;
}

static int alsa_hw_params(struct snd_pcm_substream *substream,
                          struct snd_pcm_hw_params *params)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
        struct xen_snd_front_info *front_info = stream->front_info;
        struct xen_front_pgdir_shbuf_cfg buf_cfg;
        int ret;

        /*
         * This callback may be called multiple times,
         * so free the previously allocated shared buffer if any.
         */
        stream_free(stream);
        ret = shbuf_setup_backstore(stream, params_buffer_bytes(params));
        if (ret < 0)
                goto fail;

        memset(&buf_cfg, 0, sizeof(buf_cfg));
        buf_cfg.xb_dev = front_info->xb_dev;
        buf_cfg.pgdir = &stream->shbuf;
        buf_cfg.num_pages = stream->num_pages;
        buf_cfg.pages = stream->pages;

        ret = xen_front_pgdir_shbuf_alloc(&buf_cfg);
        if (ret < 0)
                goto fail;

        ret = xen_front_pgdir_shbuf_map(&stream->shbuf);
        if (ret < 0)
                goto fail;

        return 0;

fail:
        stream_free(stream);
        dev_err(&front_info->xb_dev->dev,
                "Failed to allocate buffers for stream with index %d\n",
                stream->index);
        return ret;
}

static int alsa_hw_free(struct snd_pcm_substream *substream)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
        int ret;

        xen_snd_front_evtchnl_set_connected(&stream->evt_pair->evt, false);

        ret = xen_snd_front_stream_close(&stream->evt_pair->req);
        stream_free(stream);
        return ret;
}

static int alsa_prepare(struct snd_pcm_substream *substream)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);

        if (!stream->is_open) {
                struct snd_pcm_runtime *runtime = substream->runtime;
                u8 sndif_format;
                int ret;

                ret = to_sndif_format(runtime->format);
                if (ret < 0) {
                        dev_err(&stream->front_info->xb_dev->dev,
                                "Unsupported sample format: %d\n",
                                runtime->format);
                        return ret;
                }
                sndif_format = ret;

                ret = xen_snd_front_stream_prepare(&stream->evt_pair->req,
                                                   &stream->shbuf,
                                                   sndif_format,
                                                   runtime->channels,
                                                   runtime->rate,
                                                   snd_pcm_lib_buffer_bytes(substream),
                                                   snd_pcm_lib_period_bytes(substream));
                if (ret < 0)
                        return ret;

                stream->is_open = true;
                xen_snd_front_evtchnl_set_connected(&stream->evt_pair->evt, true);
        }

        return 0;
}

static int alsa_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
        int type;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                type = XENSND_OP_TRIGGER_START;
                break;

        case SNDRV_PCM_TRIGGER_RESUME:
                type = XENSND_OP_TRIGGER_RESUME;
                break;

        case SNDRV_PCM_TRIGGER_STOP:
                type = XENSND_OP_TRIGGER_STOP;
                break;

        case SNDRV_PCM_TRIGGER_SUSPEND:
                type = XENSND_OP_TRIGGER_PAUSE;
                break;

        default:
                return -EINVAL;
        }

        return xen_snd_front_stream_trigger(&stream->evt_pair->req, type);
}

void xen_snd_front_alsa_handle_cur_pos(struct xen_snd_front_evtchnl *evtchnl,
                                       u64 pos_bytes)
{
        struct snd_pcm_substream *substream = evtchnl->u.evt.substream;
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        snd_pcm_uframes_t delta, new_hw_ptr, cur_frame;

        if (!runtime->buffer_size || !runtime->period_size)
                return;

        cur_frame = bytes_to_frames(runtime, pos_bytes);

        delta = cur_frame - stream->be_cur_frame;
        stream->be_cur_frame = cur_frame;

        new_hw_ptr = (snd_pcm_uframes_t)atomic_read(&stream->hw_ptr);
        new_hw_ptr = (new_hw_ptr + delta) % runtime->buffer_size;
        atomic_set(&stream->hw_ptr, (int)new_hw_ptr);

        stream->out_frames += delta;
        if (stream->out_frames > runtime->period_size) {
                stream->out_frames %= runtime->period_size;
                snd_pcm_period_elapsed(substream);
        }
}

static snd_pcm_uframes_t alsa_pointer(struct snd_pcm_substream *substream)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);

        return (snd_pcm_uframes_t)atomic_read(&stream->hw_ptr);
}

static int alsa_pb_copy(struct snd_pcm_substream *substream,
                        int channel, unsigned long pos, struct iov_iter *src,
                        unsigned long count)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);

        if (unlikely(pos + count > stream->buffer_sz))
                return -EINVAL;

        if (copy_from_iter(stream->buffer + pos, count, src) != count)
                return -EFAULT;

        return xen_snd_front_stream_write(&stream->evt_pair->req, pos, count);
}

static int alsa_cap_copy(struct snd_pcm_substream *substream,
                         int channel, unsigned long pos, struct iov_iter *dst,
                         unsigned long count)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
        int ret;

        if (unlikely(pos + count > stream->buffer_sz))
                return -EINVAL;

        ret = xen_snd_front_stream_read(&stream->evt_pair->req, pos, count);
        if (ret < 0)
                return ret;

        if (copy_to_iter(stream->buffer + pos, count, dst) != count)
                return -EFAULT;
        return 0;
}

static int alsa_pb_fill_silence(struct snd_pcm_substream *substream,
                                int channel, unsigned long pos,
                                unsigned long count)
{
        struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);

        if (unlikely(pos + count > stream->buffer_sz))
                return -EINVAL;

        memset(stream->buffer + pos, 0, count);

        return xen_snd_front_stream_write(&stream->evt_pair->req, pos, count);
}

/*
 * FIXME: The mmaped data transfer is asynchronous and there is no
 * ack signal from user-space when it is done. This is the
 * reason it is not implemented in the PV driver as we do need
 * to know when the buffer can be transferred to the backend.
 */

static const struct snd_pcm_ops snd_drv_alsa_playback_ops = {
        .open           = alsa_open,
        .close          = alsa_close,
        .hw_params      = alsa_hw_params,
        .hw_free        = alsa_hw_free,
        .prepare        = alsa_prepare,
        .trigger        = alsa_trigger,
        .pointer        = alsa_pointer,
        .copy           = alsa_pb_copy,
        .fill_silence   = alsa_pb_fill_silence,
};

static const struct snd_pcm_ops snd_drv_alsa_capture_ops = {
        .open           = alsa_open,
        .close          = alsa_close,
        .hw_params      = alsa_hw_params,
        .hw_free        = alsa_hw_free,
        .prepare        = alsa_prepare,
        .trigger        = alsa_trigger,
        .pointer        = alsa_pointer,
        .copy           = alsa_cap_copy,
};

static int new_pcm_instance(struct xen_snd_front_card_info *card_info,
                            struct xen_front_cfg_pcm_instance *instance_cfg,
                            struct xen_snd_front_pcm_instance_info *pcm_instance_info)
{
        struct snd_pcm *pcm;
        int ret, i;

        dev_dbg(&card_info->front_info->xb_dev->dev,
                "New PCM device \"%s\" with id %d playback %d capture %d",
                instance_cfg->name,
                instance_cfg->device_id,
                instance_cfg->num_streams_pb,
                instance_cfg->num_streams_cap);

        pcm_instance_info->card_info = card_info;

        pcm_instance_info->pcm_hw = instance_cfg->pcm_hw;

        if (instance_cfg->num_streams_pb) {
                pcm_instance_info->streams_pb =
                                devm_kcalloc(&card_info->card->card_dev,
                                             instance_cfg->num_streams_pb,
                                             sizeof(struct xen_snd_front_pcm_stream_info),
                                             GFP_KERNEL);
                if (!pcm_instance_info->streams_pb)
                        return -ENOMEM;
        }

        if (instance_cfg->num_streams_cap) {
                pcm_instance_info->streams_cap =
                                devm_kcalloc(&card_info->card->card_dev,
                                             instance_cfg->num_streams_cap,
                                             sizeof(struct xen_snd_front_pcm_stream_info),
                                             GFP_KERNEL);
                if (!pcm_instance_info->streams_cap)
                        return -ENOMEM;
        }

        pcm_instance_info->num_pcm_streams_pb =
                        instance_cfg->num_streams_pb;
        pcm_instance_info->num_pcm_streams_cap =
                        instance_cfg->num_streams_cap;

        for (i = 0; i < pcm_instance_info->num_pcm_streams_pb; i++) {
                pcm_instance_info->streams_pb[i].pcm_hw =
                        instance_cfg->streams_pb[i].pcm_hw;
                pcm_instance_info->streams_pb[i].index =
                        instance_cfg->streams_pb[i].index;
        }

        for (i = 0; i < pcm_instance_info->num_pcm_streams_cap; i++) {
                pcm_instance_info->streams_cap[i].pcm_hw =
                        instance_cfg->streams_cap[i].pcm_hw;
                pcm_instance_info->streams_cap[i].index =
                        instance_cfg->streams_cap[i].index;
        }

        ret = snd_pcm_new(card_info->card, instance_cfg->name,
                          instance_cfg->device_id,
                          instance_cfg->num_streams_pb,
                          instance_cfg->num_streams_cap,
                          &pcm);
        if (ret < 0)
                return ret;

        pcm->private_data = pcm_instance_info;
        pcm->info_flags = 0;
        /* we want to handle all PCM operations in non-atomic context */
        pcm->nonatomic = true;
        strscpy(pcm->name, "Virtual card PCM", sizeof(pcm->name));

        if (instance_cfg->num_streams_pb)
                snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
                                &snd_drv_alsa_playback_ops);

        if (instance_cfg->num_streams_cap)
                snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
                                &snd_drv_alsa_capture_ops);

        pcm_instance_info->pcm = pcm;
        return 0;
}

int xen_snd_front_alsa_init(struct xen_snd_front_info *front_info)
{
        struct device *dev = &front_info->xb_dev->dev;
        struct xen_front_cfg_card *cfg = &front_info->cfg;
        struct xen_snd_front_card_info *card_info;
        struct snd_card *card;
        int ret, i;

        dev_dbg(dev, "Creating virtual sound card\n");

        ret = snd_card_new(dev, 0, XENSND_DRIVER_NAME, THIS_MODULE,
                           sizeof(struct xen_snd_front_card_info), &card);
        if (ret < 0)
                return ret;

        card_info = card->private_data;
        card_info->front_info = front_info;
        front_info->card_info = card_info;
        card_info->card = card;
        card_info->pcm_instances =
                        devm_kcalloc(dev, cfg->num_pcm_instances,
                                     sizeof(struct xen_snd_front_pcm_instance_info),
                                     GFP_KERNEL);
        if (!card_info->pcm_instances) {
                ret = -ENOMEM;
                goto fail;
        }

        card_info->num_pcm_instances = cfg->num_pcm_instances;
        card_info->pcm_hw = cfg->pcm_hw;

        for (i = 0; i < cfg->num_pcm_instances; i++) {
                ret = new_pcm_instance(card_info, &cfg->pcm_instances[i],
                                       &card_info->pcm_instances[i]);
                if (ret < 0)
                        goto fail;
        }

        strscpy(card->driver, XENSND_DRIVER_NAME, sizeof(card->driver));
        strscpy(card->shortname, cfg->name_short, sizeof(card->shortname));
        strscpy(card->longname, cfg->name_long, sizeof(card->longname));

        ret = snd_card_register(card);
        if (ret < 0)
                goto fail;

        return 0;

fail:
        snd_card_free(card);
        return ret;
}

void xen_snd_front_alsa_fini(struct xen_snd_front_info *front_info)
{
        struct xen_snd_front_card_info *card_info;
        struct snd_card *card;

        card_info = front_info->card_info;
        if (!card_info)
                return;

        card = card_info->card;
        if (!card)
                return;

        dev_dbg(&front_info->xb_dev->dev, "Removing virtual sound card %d\n",
                card->number);
        snd_card_free(card);

        /* Card_info will be freed when destroying front_info->xb_dev->dev. */
        card_info->card = NULL;
}