// SPDX-License-Identifier: GPL-2.0+
/*
 * virtio-snd: Virtio sound device
 * Copyright (C) 2021 OpenSynergy GmbH
 */
#include <linux/moduleparam.h>
#include <linux/virtio_config.h>

#include "virtio_card.h"

static u32 pcm_buffer_ms = 160;
module_param(pcm_buffer_ms, uint, 0644);
MODULE_PARM_DESC(pcm_buffer_ms, "PCM substream buffer time in milliseconds");

static u32 pcm_periods_min = 2;
module_param(pcm_periods_min, uint, 0644);
MODULE_PARM_DESC(pcm_periods_min, "Minimum number of PCM periods");

static u32 pcm_periods_max = 16;
module_param(pcm_periods_max, uint, 0644);
MODULE_PARM_DESC(pcm_periods_max, "Maximum number of PCM periods");

static u32 pcm_period_ms_min = 10;
module_param(pcm_period_ms_min, uint, 0644);
MODULE_PARM_DESC(pcm_period_ms_min, "Minimum PCM period time in milliseconds");

static u32 pcm_period_ms_max = 80;
module_param(pcm_period_ms_max, uint, 0644);
MODULE_PARM_DESC(pcm_period_ms_max, "Maximum PCM period time in milliseconds");

/* Map for converting VirtIO format to ALSA format. */
static const snd_pcm_format_t g_v2a_format_map[] = {
        [VIRTIO_SND_PCM_FMT_IMA_ADPCM] = SNDRV_PCM_FORMAT_IMA_ADPCM,
        [VIRTIO_SND_PCM_FMT_MU_LAW] = SNDRV_PCM_FORMAT_MU_LAW,
        [VIRTIO_SND_PCM_FMT_A_LAW] = SNDRV_PCM_FORMAT_A_LAW,
        [VIRTIO_SND_PCM_FMT_S8] = SNDRV_PCM_FORMAT_S8,
        [VIRTIO_SND_PCM_FMT_U8] = SNDRV_PCM_FORMAT_U8,
        [VIRTIO_SND_PCM_FMT_S16] = SNDRV_PCM_FORMAT_S16_LE,
        [VIRTIO_SND_PCM_FMT_U16] = SNDRV_PCM_FORMAT_U16_LE,
        [VIRTIO_SND_PCM_FMT_S18_3] = SNDRV_PCM_FORMAT_S18_3LE,
        [VIRTIO_SND_PCM_FMT_U18_3] = SNDRV_PCM_FORMAT_U18_3LE,
        [VIRTIO_SND_PCM_FMT_S20_3] = SNDRV_PCM_FORMAT_S20_3LE,
        [VIRTIO_SND_PCM_FMT_U20_3] = SNDRV_PCM_FORMAT_U20_3LE,
        [VIRTIO_SND_PCM_FMT_S24_3] = SNDRV_PCM_FORMAT_S24_3LE,
        [VIRTIO_SND_PCM_FMT_U24_3] = SNDRV_PCM_FORMAT_U24_3LE,
        [VIRTIO_SND_PCM_FMT_S20] = SNDRV_PCM_FORMAT_S20_LE,
        [VIRTIO_SND_PCM_FMT_U20] = SNDRV_PCM_FORMAT_U20_LE,
        [VIRTIO_SND_PCM_FMT_S24] = SNDRV_PCM_FORMAT_S24_LE,
        [VIRTIO_SND_PCM_FMT_U24] = SNDRV_PCM_FORMAT_U24_LE,
        [VIRTIO_SND_PCM_FMT_S32] = SNDRV_PCM_FORMAT_S32_LE,
        [VIRTIO_SND_PCM_FMT_U32] = SNDRV_PCM_FORMAT_U32_LE,
        [VIRTIO_SND_PCM_FMT_FLOAT] = SNDRV_PCM_FORMAT_FLOAT_LE,
        [VIRTIO_SND_PCM_FMT_FLOAT64] = SNDRV_PCM_FORMAT_FLOAT64_LE,
        [VIRTIO_SND_PCM_FMT_DSD_U8] = SNDRV_PCM_FORMAT_DSD_U8,
        [VIRTIO_SND_PCM_FMT_DSD_U16] = SNDRV_PCM_FORMAT_DSD_U16_LE,
        [VIRTIO_SND_PCM_FMT_DSD_U32] = SNDRV_PCM_FORMAT_DSD_U32_LE,
        [VIRTIO_SND_PCM_FMT_IEC958_SUBFRAME] =
                SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE
};

/* Map for converting VirtIO frame rate to ALSA frame rate. */
struct virtsnd_v2a_rate {
        unsigned int alsa_bit;
        unsigned int rate;
};

static const struct virtsnd_v2a_rate g_v2a_rate_map[] = {
        [VIRTIO_SND_PCM_RATE_5512] = { SNDRV_PCM_RATE_5512, 5512 },
        [VIRTIO_SND_PCM_RATE_8000] = { SNDRV_PCM_RATE_8000, 8000 },
        [VIRTIO_SND_PCM_RATE_11025] = { SNDRV_PCM_RATE_11025, 11025 },
        [VIRTIO_SND_PCM_RATE_16000] = { SNDRV_PCM_RATE_16000, 16000 },
        [VIRTIO_SND_PCM_RATE_22050] = { SNDRV_PCM_RATE_22050, 22050 },
        [VIRTIO_SND_PCM_RATE_32000] = { SNDRV_PCM_RATE_32000, 32000 },
        [VIRTIO_SND_PCM_RATE_44100] = { SNDRV_PCM_RATE_44100, 44100 },
        [VIRTIO_SND_PCM_RATE_48000] = { SNDRV_PCM_RATE_48000, 48000 },
        [VIRTIO_SND_PCM_RATE_64000] = { SNDRV_PCM_RATE_64000, 64000 },
        [VIRTIO_SND_PCM_RATE_88200] = { SNDRV_PCM_RATE_88200, 88200 },
        [VIRTIO_SND_PCM_RATE_96000] = { SNDRV_PCM_RATE_96000, 96000 },
        [VIRTIO_SND_PCM_RATE_176400] = { SNDRV_PCM_RATE_176400, 176400 },
        [VIRTIO_SND_PCM_RATE_192000] = { SNDRV_PCM_RATE_192000, 192000 }
};

/**
 * virtsnd_pcm_build_hw() - Parse substream config and build HW descriptor.
 * @vss: VirtIO substream.
 * @info: VirtIO substream information entry.
 *
 * Context: Any context.
 * Return: 0 on success, -EINVAL if configuration is invalid.
 */
static int virtsnd_pcm_build_hw(struct virtio_pcm_substream *vss,
                                struct virtio_snd_pcm_info *info)
{
        struct virtio_device *vdev = vss->snd->vdev;
        unsigned int i;
        u64 values;
        size_t sample_max = 0;
        size_t sample_min = 0;

        vss->features = le32_to_cpu(info->features);

        /*
         * TODO: set SNDRV_PCM_INFO_{BATCH,BLOCK_TRANSFER} if device supports
         * only message-based transport.
         */
        vss->hw.info =
                SNDRV_PCM_INFO_MMAP |
                SNDRV_PCM_INFO_MMAP_VALID |
                SNDRV_PCM_INFO_BATCH |
                SNDRV_PCM_INFO_BLOCK_TRANSFER |
                SNDRV_PCM_INFO_INTERLEAVED |
                SNDRV_PCM_INFO_PAUSE |
                SNDRV_PCM_INFO_NO_REWINDS |
                SNDRV_PCM_INFO_SYNC_APPLPTR;

        if (!info->channels_min || info->channels_min > info->channels_max) {
                dev_err(&vdev->dev,
                        "SID %u: invalid channel range [%u %u]\n",
                        vss->sid, info->channels_min, info->channels_max);
                return -EINVAL;
        }

        vss->hw.channels_min = info->channels_min;
        vss->hw.channels_max = info->channels_max;

        values = le64_to_cpu(info->formats);

        vss->hw.formats = 0;

        for (i = 0; i < ARRAY_SIZE(g_v2a_format_map); ++i)
                if (values & (1ULL << i)) {
                        snd_pcm_format_t alsa_fmt = g_v2a_format_map[i];
                        int bytes = snd_pcm_format_physical_width(alsa_fmt) / 8;

                        if (!sample_min || sample_min > bytes)
                                sample_min = bytes;

                        if (sample_max < bytes)
                                sample_max = bytes;

                        vss->hw.formats |= pcm_format_to_bits(alsa_fmt);
                }

        if (!vss->hw.formats) {
                dev_err(&vdev->dev,
                        "SID %u: no supported PCM sample formats found\n",
                        vss->sid);
                return -EINVAL;
        }

        values = le64_to_cpu(info->rates);

        vss->hw.rates = 0;

        for (i = 0; i < ARRAY_SIZE(g_v2a_rate_map); ++i)
                if (values & (1ULL << i)) {
                        if (!vss->hw.rate_min ||
                            vss->hw.rate_min > g_v2a_rate_map[i].rate)
                                vss->hw.rate_min = g_v2a_rate_map[i].rate;

                        if (vss->hw.rate_max < g_v2a_rate_map[i].rate)
                                vss->hw.rate_max = g_v2a_rate_map[i].rate;

                        vss->hw.rates |= g_v2a_rate_map[i].alsa_bit;
                }

        if (!vss->hw.rates) {
                dev_err(&vdev->dev,
                        "SID %u: no supported PCM frame rates found\n",
                        vss->sid);
                return -EINVAL;
        }

        vss->hw.periods_min = pcm_periods_min;
        vss->hw.periods_max = pcm_periods_max;

        /*
         * We must ensure that there is enough space in the buffer to store
         * pcm_buffer_ms ms for the combination (Cmax, Smax, Rmax), where:
         *   Cmax = maximum supported number of channels,
         *   Smax = maximum supported sample size in bytes,
         *   Rmax = maximum supported frame rate.
         */
        vss->hw.buffer_bytes_max =
                PAGE_ALIGN(sample_max * vss->hw.channels_max * pcm_buffer_ms *
                           (vss->hw.rate_max / MSEC_PER_SEC));

        /*
         * We must ensure that the minimum period size is enough to store
         * pcm_period_ms_min ms for the combination (Cmin, Smin, Rmin), where:
         *   Cmin = minimum supported number of channels,
         *   Smin = minimum supported sample size in bytes,
         *   Rmin = minimum supported frame rate.
         */
        vss->hw.period_bytes_min =
                sample_min * vss->hw.channels_min * pcm_period_ms_min *
                (vss->hw.rate_min / MSEC_PER_SEC);

        /*
         * We must ensure that the maximum period size is enough to store
         * pcm_period_ms_max ms for the combination (Cmax, Smax, Rmax).
         */
        vss->hw.period_bytes_max =
                sample_max * vss->hw.channels_max * pcm_period_ms_max *
                (vss->hw.rate_max / MSEC_PER_SEC);

        return 0;
}

/**
 * virtsnd_pcm_find() - Find the PCM device for the specified node ID.
 * @snd: VirtIO sound device.
 * @nid: Function node ID.
 *
 * Context: Any context.
 * Return: a pointer to the PCM device or ERR_PTR(-ENOENT).
 */
struct virtio_pcm *virtsnd_pcm_find(struct virtio_snd *snd, u32 nid)
{
        struct virtio_pcm *vpcm;

        list_for_each_entry(vpcm, &snd->pcm_list, list)
                if (vpcm->nid == nid)
                        return vpcm;

        return ERR_PTR(-ENOENT);
}

/**
 * virtsnd_pcm_find_or_create() - Find or create the PCM device for the
 *                                specified node ID.
 * @snd: VirtIO sound device.
 * @nid: Function node ID.
 *
 * Context: Any context that permits to sleep.
 * Return: a pointer to the PCM device or ERR_PTR(-errno).
 */
struct virtio_pcm *virtsnd_pcm_find_or_create(struct virtio_snd *snd, u32 nid)
{
        struct virtio_device *vdev = snd->vdev;
        struct virtio_pcm *vpcm;

        vpcm = virtsnd_pcm_find(snd, nid);
        if (!IS_ERR(vpcm))
                return vpcm;

        vpcm = devm_kzalloc(&vdev->dev, sizeof(*vpcm), GFP_KERNEL);
        if (!vpcm)
                return ERR_PTR(-ENOMEM);

        vpcm->nid = nid;
        list_add_tail(&vpcm->list, &snd->pcm_list);

        return vpcm;
}

/**
 * virtsnd_pcm_validate() - Validate if the device can be started.
 * @vdev: VirtIO parent device.
 *
 * Context: Any context.
 * Return: 0 on success, -EINVAL on failure.
 */
int virtsnd_pcm_validate(struct virtio_device *vdev)
{
        if (pcm_periods_min < 2 || pcm_periods_min > pcm_periods_max) {
                dev_err(&vdev->dev,
                        "invalid range [%u %u] of the number of PCM periods\n",
                        pcm_periods_min, pcm_periods_max);
                return -EINVAL;
        }

        if (!pcm_period_ms_min || pcm_period_ms_min > pcm_period_ms_max) {
                dev_err(&vdev->dev,
                        "invalid range [%u %u] of the size of the PCM period\n",
                        pcm_period_ms_min, pcm_period_ms_max);
                return -EINVAL;
        }

        if (pcm_buffer_ms < pcm_periods_min * pcm_period_ms_min) {
                dev_err(&vdev->dev,
                        "pcm_buffer_ms(=%u) value cannot be < %u ms\n",
                        pcm_buffer_ms, pcm_periods_min * pcm_period_ms_min);
                return -EINVAL;
        }

        if (pcm_period_ms_max > pcm_buffer_ms / 2) {
                dev_err(&vdev->dev,
                        "pcm_period_ms_max(=%u) value cannot be > %u ms\n",
                        pcm_period_ms_max, pcm_buffer_ms / 2);
                return -EINVAL;
        }

        return 0;
}

/**
 * virtsnd_pcm_period_elapsed() - Kernel work function to handle the elapsed
 *                                period state.
 * @work: Elapsed period work.
 *
 * The main purpose of this function is to call snd_pcm_period_elapsed() in
 * a process context, not in an interrupt context. This is necessary because PCM
 * devices operate in non-atomic mode.
 *
 * Context: Process context.
 */
static void virtsnd_pcm_period_elapsed(struct work_struct *work)
{
        struct virtio_pcm_substream *vss =
                container_of(work, struct virtio_pcm_substream, elapsed_period);

        snd_pcm_period_elapsed(vss->substream);
}

/**
 * virtsnd_pcm_parse_cfg() - Parse the stream configuration.
 * @snd: VirtIO sound device.
 *
 * This function is called during initial device initialization.
 *
 * Context: Any context that permits to sleep.
 * Return: 0 on success, -errno on failure.
 */
int virtsnd_pcm_parse_cfg(struct virtio_snd *snd)
{
        struct virtio_device *vdev = snd->vdev;
        struct virtio_snd_pcm_info *info;
        u32 i;
        int rc;

        virtio_cread_le(vdev, struct virtio_snd_config, streams,
                        &snd->nsubstreams);
        if (!snd->nsubstreams)
                return 0;

        snd->substreams = devm_kcalloc(&vdev->dev, snd->nsubstreams,
                                       sizeof(*snd->substreams), GFP_KERNEL);
        if (!snd->substreams)
                return -ENOMEM;

        /*
         * Initialize critical substream fields early in case we hit an
         * error path and end up trying to clean up uninitialized structures
         * elsewhere.
         */
        for (i = 0; i < snd->nsubstreams; ++i) {
                struct virtio_pcm_substream *vss = &snd->substreams[i];

                vss->snd = snd;
                vss->sid = i;
                INIT_WORK(&vss->elapsed_period, virtsnd_pcm_period_elapsed);
                init_waitqueue_head(&vss->msg_empty);
                spin_lock_init(&vss->lock);
        }

        info = kzalloc_objs(*info, snd->nsubstreams);
        if (!info)
                return -ENOMEM;

        rc = virtsnd_ctl_query_info(snd, VIRTIO_SND_R_PCM_INFO, 0,
                                    snd->nsubstreams, sizeof(*info), info);
        if (rc)
                goto on_exit;

        for (i = 0; i < snd->nsubstreams; ++i) {
                struct virtio_pcm_substream *vss = &snd->substreams[i];
                struct virtio_pcm *vpcm;

                rc = virtsnd_pcm_build_hw(vss, &info[i]);
                if (rc)
                        goto on_exit;

                vss->nid = le32_to_cpu(info[i].hdr.hda_fn_nid);

                vpcm = virtsnd_pcm_find_or_create(snd, vss->nid);
                if (IS_ERR(vpcm)) {
                        rc = PTR_ERR(vpcm);
                        goto on_exit;
                }

                switch (info[i].direction) {
                case VIRTIO_SND_D_OUTPUT:
                        vss->direction = SNDRV_PCM_STREAM_PLAYBACK;
                        break;
                case VIRTIO_SND_D_INPUT:
                        vss->direction = SNDRV_PCM_STREAM_CAPTURE;
                        break;
                default:
                        dev_err(&vdev->dev, "SID %u: unknown direction (%u)\n",
                                vss->sid, info[i].direction);
                        rc = -EINVAL;
                        goto on_exit;
                }

                vpcm->streams[vss->direction].nsubstreams++;
        }

on_exit:
        kfree(info);

        return rc;
}

/**
 * virtsnd_pcm_build_devs() - Build ALSA PCM devices.
 * @snd: VirtIO sound device.
 *
 * Context: Any context that permits to sleep.
 * Return: 0 on success, -errno on failure.
 */
int virtsnd_pcm_build_devs(struct virtio_snd *snd)
{
        struct virtio_device *vdev = snd->vdev;
        struct virtio_pcm *vpcm;
        u32 i;
        int rc;

        list_for_each_entry(vpcm, &snd->pcm_list, list) {
                unsigned int npbs =
                        vpcm->streams[SNDRV_PCM_STREAM_PLAYBACK].nsubstreams;
                unsigned int ncps =
                        vpcm->streams[SNDRV_PCM_STREAM_CAPTURE].nsubstreams;

                if (!npbs && !ncps)
                        continue;

                rc = snd_pcm_new(snd->card, VIRTIO_SND_CARD_DRIVER, vpcm->nid,
                                 npbs, ncps, &vpcm->pcm);
                if (rc) {
                        dev_err(&vdev->dev, "snd_pcm_new[%u] failed: %d\n",
                                vpcm->nid, rc);
                        return rc;
                }

                vpcm->pcm->info_flags = 0;
                vpcm->pcm->dev_class = SNDRV_PCM_CLASS_GENERIC;
                vpcm->pcm->dev_subclass = SNDRV_PCM_SUBCLASS_GENERIC_MIX;
                snprintf(vpcm->pcm->name, sizeof(vpcm->pcm->name),
                         VIRTIO_SND_PCM_NAME " %u", vpcm->pcm->device);
                vpcm->pcm->private_data = vpcm;
                vpcm->pcm->nonatomic = true;

                for (i = 0; i < ARRAY_SIZE(vpcm->streams); ++i) {
                        struct virtio_pcm_stream *stream = &vpcm->streams[i];

                        if (!stream->nsubstreams)
                                continue;

                        stream->substreams =
                                devm_kcalloc(&vdev->dev, stream->nsubstreams,
                                             sizeof(*stream->substreams),
                                             GFP_KERNEL);
                        if (!stream->substreams)
                                return -ENOMEM;

                        stream->nsubstreams = 0;
                }
        }

        for (i = 0; i < snd->nsubstreams; ++i) {
                struct virtio_pcm_stream *vs;
                struct virtio_pcm_substream *vss = &snd->substreams[i];

                vpcm = virtsnd_pcm_find(snd, vss->nid);
                if (IS_ERR(vpcm))
                        return PTR_ERR(vpcm);

                vs = &vpcm->streams[vss->direction];
                vs->substreams[vs->nsubstreams++] = vss;
        }

        list_for_each_entry(vpcm, &snd->pcm_list, list) {
                for (i = 0; i < ARRAY_SIZE(vpcm->streams); ++i) {
                        struct virtio_pcm_stream *vs = &vpcm->streams[i];
                        struct snd_pcm_str *ks = &vpcm->pcm->streams[i];
                        struct snd_pcm_substream *kss;

                        if (!vs->nsubstreams)
                                continue;

                        for (kss = ks->substream; kss; kss = kss->next)
                                vs->substreams[kss->number]->substream = kss;

                        snd_pcm_set_ops(vpcm->pcm, i, &virtsnd_pcm_ops[i]);
                }

                snd_pcm_set_managed_buffer_all(vpcm->pcm,
                                               SNDRV_DMA_TYPE_VMALLOC, NULL,
                                               0, 0);
        }

        return 0;
}

/**
 * virtsnd_pcm_event() - Handle the PCM device event notification.
 * @snd: VirtIO sound device.
 * @event: VirtIO sound event.
 *
 * Context: Interrupt context.
 */
void virtsnd_pcm_event(struct virtio_snd *snd, struct virtio_snd_event *event)
{
        struct virtio_pcm_substream *vss;
        u32 sid = le32_to_cpu(event->data);

        if (sid >= snd->nsubstreams)
                return;

        vss = &snd->substreams[sid];

        switch (le32_to_cpu(event->hdr.code)) {
        case VIRTIO_SND_EVT_PCM_PERIOD_ELAPSED:
                /* TODO: deal with shmem elapsed period */
                break;
        case VIRTIO_SND_EVT_PCM_XRUN:
                scoped_guard(spinlock, &vss->lock) {
                        if (vss->xfer_enabled)
                                vss->xfer_xrun = true;
                }
                break;
        }
}