// SPDX-License-Identifier: GPL-2.0-only
/*
 * oxfw_stream.c - a part of driver for OXFW970/971 based devices
 *
 * Copyright (c) 2014 Takashi Sakamoto
 */

#include "oxfw.h"
#include <linux/delay.h>

#define AVC_GENERIC_FRAME_MAXIMUM_BYTES 512
#define READY_TIMEOUT_MS        200

/*
 * According to datasheet of Oxford Semiconductor:
 *  OXFW970: 32.0/44.1/48.0/96.0 Khz, 8 audio channels I/O
 *  OXFW971: 32.0/44.1/48.0/88.2/96.0/192.0 kHz, 16 audio channels I/O, MIDI I/O
 */
static const unsigned int oxfw_rate_table[] = {
        [0] = 32000,
        [1] = 44100,
        [2] = 48000,
        [3] = 88200,
        [4] = 96000,
        [5] = 192000,
};

/*
 * See Table 5.7 – Sampling frequency for Multi-bit Audio
 * in AV/C Stream Format Information Specification 1.1 (Apr 2005, 1394TA)
 */
static const unsigned int avc_stream_rate_table[] = {
        [0] = 0x02,
        [1] = 0x03,
        [2] = 0x04,
        [3] = 0x0a,
        [4] = 0x05,
        [5] = 0x07,
};

static int set_rate(struct snd_oxfw *oxfw, unsigned int rate)
{
        int err;

        err = avc_general_set_sig_fmt(oxfw->unit, rate,
                                      AVC_GENERAL_PLUG_DIR_IN, 0);
        if (err < 0)
                goto end;

        if (oxfw->has_output)
                err = avc_general_set_sig_fmt(oxfw->unit, rate,
                                              AVC_GENERAL_PLUG_DIR_OUT, 0);
end:
        return err;
}

static int set_stream_format(struct snd_oxfw *oxfw, struct amdtp_stream *s,
                             unsigned int rate, unsigned int pcm_channels)
{
        u8 **formats;
        struct snd_oxfw_stream_formation formation;
        enum avc_general_plug_dir dir;
        unsigned int len;
        int i, err;

        if (s == &oxfw->tx_stream) {
                formats = oxfw->tx_stream_formats;
                dir = AVC_GENERAL_PLUG_DIR_OUT;
        } else {
                formats = oxfw->rx_stream_formats;
                dir = AVC_GENERAL_PLUG_DIR_IN;
        }

        /* Seek stream format for requirements. */
        for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
                err = snd_oxfw_stream_parse_format(formats[i], &formation);
                if (err < 0)
                        return err;

                if ((formation.rate == rate) && (formation.pcm == pcm_channels))
                        break;
        }
        if (i == SND_OXFW_STREAM_FORMAT_ENTRIES)
                return -EINVAL;

        /* If assumed, just change rate. */
        if (oxfw->assumed)
                return set_rate(oxfw, rate);

        /* Calculate format length. */
        len = 5 + formats[i][4] * 2;

        err = avc_stream_set_format(oxfw->unit, dir, 0, formats[i], len);
        if (err < 0)
                return err;

        /* Some requests just after changing format causes freezing. */
        msleep(100);

        return 0;
}

static int start_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
{
        struct cmp_connection *conn;
        int err;

        if (stream == &oxfw->rx_stream)
                conn = &oxfw->in_conn;
        else
                conn = &oxfw->out_conn;

        err = cmp_connection_establish(conn);
        if (err < 0)
                return err;

        err = amdtp_domain_add_stream(&oxfw->domain, stream,
                                      conn->resources.channel, conn->speed);
        if (err < 0) {
                cmp_connection_break(conn);
                return err;
        }

        return 0;
}

static int check_connection_used_by_others(struct snd_oxfw *oxfw,
                                           struct amdtp_stream *stream)
{
        struct cmp_connection *conn;
        bool used;
        int err;

        if (stream == &oxfw->tx_stream)
                conn = &oxfw->out_conn;
        else
                conn = &oxfw->in_conn;

        err = cmp_connection_check_used(conn, &used);
        if ((err >= 0) && used && !amdtp_stream_running(stream)) {
                dev_err(&oxfw->unit->device,
                        "Connection established by others: %cPCR[%d]\n",
                        (conn->direction == CMP_OUTPUT) ? 'o' : 'i',
                        conn->pcr_index);
                err = -EBUSY;
        }

        return err;
}

static int init_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
{
        struct cmp_connection *conn;
        enum cmp_direction c_dir;
        enum amdtp_stream_direction s_dir;
        unsigned int flags = 0;
        int err;

        if (!(oxfw->quirks & SND_OXFW_QUIRK_BLOCKING_TRANSMISSION))
                flags |= CIP_NONBLOCKING;
        else
                flags |= CIP_BLOCKING;

        // OXFW 970/971 has no function to generate playback timing according to the sequence
        // of value in syt field, thus the packet should include NO_INFO value in the field.
        // However, some models just ignore data blocks in packet with NO_INFO for audio data
        // processing.
        if (!(oxfw->quirks & SND_OXFW_QUIRK_IGNORE_NO_INFO_PACKET))
                flags |= CIP_UNAWARE_SYT;

        if (stream == &oxfw->tx_stream) {
                conn = &oxfw->out_conn;
                c_dir = CMP_OUTPUT;
                s_dir = AMDTP_IN_STREAM;

                if (oxfw->quirks & SND_OXFW_QUIRK_JUMBO_PAYLOAD)
                        flags |= CIP_JUMBO_PAYLOAD;
                if (oxfw->quirks & SND_OXFW_QUIRK_WRONG_DBS)
                        flags |= CIP_WRONG_DBS;
        } else {
                conn = &oxfw->in_conn;
                c_dir = CMP_INPUT;
                s_dir = AMDTP_OUT_STREAM;
        }

        err = cmp_connection_init(conn, oxfw->unit, c_dir, 0);
        if (err < 0)
                return err;

        err = amdtp_am824_init(stream, oxfw->unit, s_dir, flags);
        if (err < 0) {
                cmp_connection_destroy(conn);
                return err;
        }

        return 0;
}

static int keep_resources(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
{
        enum avc_general_plug_dir dir;
        u8 **formats;
        struct snd_oxfw_stream_formation formation;
        struct cmp_connection *conn;
        int i;
        int err;

        if (stream == &oxfw->rx_stream) {
                dir = AVC_GENERAL_PLUG_DIR_IN;
                formats = oxfw->rx_stream_formats;
                conn = &oxfw->in_conn;
        } else {
                dir = AVC_GENERAL_PLUG_DIR_OUT;
                formats = oxfw->tx_stream_formats;
                conn = &oxfw->out_conn;
        }

        err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation);
        if (err < 0)
                return err;

        for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
                struct snd_oxfw_stream_formation fmt;

                if (formats[i] == NULL)
                        break;

                err = snd_oxfw_stream_parse_format(formats[i], &fmt);
                if (err < 0)
                        return err;

                if (fmt.rate == formation.rate && fmt.pcm == formation.pcm &&
                    fmt.midi == formation.midi)
                        break;
        }
        if (i == SND_OXFW_STREAM_FORMAT_ENTRIES)
                return -EINVAL;

        // The stream should have one pcm channels at least.
        if (formation.pcm == 0)
                return -EINVAL;

        err = amdtp_am824_set_parameters(stream, formation.rate, formation.pcm,
                                         formation.midi * 8, false);
        if (err < 0)
                return err;

        return cmp_connection_reserve(conn, amdtp_stream_get_max_payload(stream));
}

int snd_oxfw_stream_reserve_duplex(struct snd_oxfw *oxfw,
                                   struct amdtp_stream *stream,
                                   unsigned int rate, unsigned int pcm_channels,
                                   unsigned int frames_per_period,
                                   unsigned int frames_per_buffer)
{
        struct snd_oxfw_stream_formation formation;
        enum avc_general_plug_dir dir;
        int err;

        // Considering JACK/FFADO streaming:
        // TODO: This can be removed hwdep functionality becomes popular.
        err = check_connection_used_by_others(oxfw, &oxfw->rx_stream);
        if (err < 0)
                return err;
        if (oxfw->has_output) {
                err = check_connection_used_by_others(oxfw, &oxfw->tx_stream);
                if (err < 0)
                        return err;
        }

        if (stream == &oxfw->tx_stream)
                dir = AVC_GENERAL_PLUG_DIR_OUT;
        else
                dir = AVC_GENERAL_PLUG_DIR_IN;

        err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation);
        if (err < 0)
                return err;
        if (rate == 0) {
                rate = formation.rate;
                pcm_channels = formation.pcm;
        }
        if (formation.rate != rate || formation.pcm != pcm_channels) {
                amdtp_domain_stop(&oxfw->domain);

                cmp_connection_break(&oxfw->in_conn);
                cmp_connection_release(&oxfw->in_conn);

                if (oxfw->has_output) {
                        cmp_connection_break(&oxfw->out_conn);
                        cmp_connection_release(&oxfw->out_conn);
                }
        }

        if (oxfw->substreams_count == 0 ||
            formation.rate != rate || formation.pcm != pcm_channels) {
                err = set_stream_format(oxfw, stream, rate, pcm_channels);
                if (err < 0) {
                        dev_err(&oxfw->unit->device,
                                "fail to set stream format: %d\n", err);
                        return err;
                }

                err = keep_resources(oxfw, &oxfw->rx_stream);
                if (err < 0)
                        return err;

                if (oxfw->has_output) {
                        err = keep_resources(oxfw, &oxfw->tx_stream);
                        if (err < 0) {
                                cmp_connection_release(&oxfw->in_conn);
                                return err;
                        }
                }

                err = amdtp_domain_set_events_per_period(&oxfw->domain,
                                        frames_per_period, frames_per_buffer);
                if (err < 0) {
                        cmp_connection_release(&oxfw->in_conn);
                        if (oxfw->has_output)
                                cmp_connection_release(&oxfw->out_conn);
                        return err;
                }
        }

        return 0;
}

int snd_oxfw_stream_start_duplex(struct snd_oxfw *oxfw)
{
        int err;

        if (oxfw->substreams_count == 0)
                return -EIO;

        if (amdtp_streaming_error(&oxfw->rx_stream) ||
            amdtp_streaming_error(&oxfw->tx_stream)) {
                amdtp_domain_stop(&oxfw->domain);

                cmp_connection_break(&oxfw->in_conn);
                if (oxfw->has_output)
                        cmp_connection_break(&oxfw->out_conn);
        }

        if (!amdtp_stream_running(&oxfw->rx_stream)) {
                unsigned int tx_init_skip_cycles = 0;
                bool replay_seq = false;

                err = start_stream(oxfw, &oxfw->rx_stream);
                if (err < 0) {
                        dev_err(&oxfw->unit->device,
                                "fail to prepare rx stream: %d\n", err);
                        goto error;
                }

                if (oxfw->has_output &&
                    !amdtp_stream_running(&oxfw->tx_stream)) {
                        err = start_stream(oxfw, &oxfw->tx_stream);
                        if (err < 0) {
                                dev_err(&oxfw->unit->device,
                                        "fail to prepare tx stream: %d\n", err);
                                goto error;
                        }

                        if (oxfw->quirks & SND_OXFW_QUIRK_JUMBO_PAYLOAD) {
                                // Just after changing sampling transfer frequency, many cycles are
                                // skipped for packet transmission.
                                tx_init_skip_cycles = 400;
                        } else {
                                replay_seq = true;
                        }
                }

                // NOTE: The device ignores presentation time expressed by the value of syt field
                // of CIP header in received packets. The sequence of the number of data blocks per
                // packet is important for media clock recovery.
                err = amdtp_domain_start(&oxfw->domain, tx_init_skip_cycles, replay_seq, false);
                if (err < 0)
                        goto error;

                if (!amdtp_domain_wait_ready(&oxfw->domain, READY_TIMEOUT_MS)) {
                        err = -ETIMEDOUT;
                        goto error;
                }
        }

        return 0;
error:
        amdtp_domain_stop(&oxfw->domain);

        cmp_connection_break(&oxfw->in_conn);
        if (oxfw->has_output)
                cmp_connection_break(&oxfw->out_conn);

        return err;
}

void snd_oxfw_stream_stop_duplex(struct snd_oxfw *oxfw)
{
        if (oxfw->substreams_count == 0) {
                amdtp_domain_stop(&oxfw->domain);

                cmp_connection_break(&oxfw->in_conn);
                cmp_connection_release(&oxfw->in_conn);

                if (oxfw->has_output) {
                        cmp_connection_break(&oxfw->out_conn);
                        cmp_connection_release(&oxfw->out_conn);
                }
        }
}

static void destroy_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
{
        struct cmp_connection *conn;

        if (stream == &oxfw->tx_stream)
                conn = &oxfw->out_conn;
        else
                conn = &oxfw->in_conn;

        amdtp_stream_destroy(stream);
        cmp_connection_destroy(conn);
}

int snd_oxfw_stream_init_duplex(struct snd_oxfw *oxfw)
{
        int err;

        err = init_stream(oxfw, &oxfw->rx_stream);
        if (err < 0)
                return err;

        if (oxfw->has_output) {
                err = init_stream(oxfw, &oxfw->tx_stream);
                if (err < 0) {
                        destroy_stream(oxfw, &oxfw->rx_stream);
                        return err;
                }
        }

        err = amdtp_domain_init(&oxfw->domain);
        if (err < 0) {
                destroy_stream(oxfw, &oxfw->rx_stream);
                if (oxfw->has_output)
                        destroy_stream(oxfw, &oxfw->tx_stream);
        }

        return err;
}

// This function should be called before starting the stream or after stopping
// the streams.
void snd_oxfw_stream_destroy_duplex(struct snd_oxfw *oxfw)
{
        amdtp_domain_destroy(&oxfw->domain);

        destroy_stream(oxfw, &oxfw->rx_stream);

        if (oxfw->has_output)
                destroy_stream(oxfw, &oxfw->tx_stream);
}

void snd_oxfw_stream_update_duplex(struct snd_oxfw *oxfw)
{
        amdtp_domain_stop(&oxfw->domain);

        cmp_connection_break(&oxfw->in_conn);

        amdtp_stream_pcm_abort(&oxfw->rx_stream);

        if (oxfw->has_output) {
                cmp_connection_break(&oxfw->out_conn);

                amdtp_stream_pcm_abort(&oxfw->tx_stream);
        }
}

int snd_oxfw_stream_get_current_formation(struct snd_oxfw *oxfw,
                                enum avc_general_plug_dir dir,
                                struct snd_oxfw_stream_formation *formation)
{
        u8 *format;
        unsigned int len;
        int err;

        len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
        format = kmalloc(len, GFP_KERNEL);
        if (format == NULL)
                return -ENOMEM;

        err = avc_stream_get_format_single(oxfw->unit, dir, 0, format, &len);
        if (err < 0)
                goto end;
        if (len < 3) {
                err = -EIO;
                goto end;
        }

        err = snd_oxfw_stream_parse_format(format, formation);
end:
        kfree(format);
        return err;
}

/*
 * See Table 6.16 - AM824 Stream Format
 *     Figure 6.19 - format_information field for AM824 Compound
 * in AV/C Stream Format Information Specification 1.1 (Apr 2005, 1394TA)
 * Also 'Clause 12 AM824 sequence adaption layers' in IEC 61883-6:2005
 */
int snd_oxfw_stream_parse_format(u8 *format,
                                 struct snd_oxfw_stream_formation *formation)
{
        unsigned int i, e, channels, type;

        memset(formation, 0, sizeof(struct snd_oxfw_stream_formation));

        /*
         * this module can support a hierarchy combination that:
         *  Root:       Audio and Music (0x90)
         *  Level 1:    AM824 Compound  (0x40)
         */
        if ((format[0] != 0x90) || (format[1] != 0x40))
                return -ENXIO;

        /* check the sampling rate */
        for (i = 0; i < ARRAY_SIZE(avc_stream_rate_table); i++) {
                if (format[2] == avc_stream_rate_table[i])
                        break;
        }
        if (i == ARRAY_SIZE(avc_stream_rate_table))
                return -ENXIO;

        formation->rate = oxfw_rate_table[i];

        for (e = 0; e < format[4]; e++) {
                channels = format[5 + e * 2];
                type = format[6 + e * 2];

                switch (type) {
                /* IEC 60958 Conformant, currently handled as MBLA */
                case 0x00:
                /* Multi Bit Linear Audio (Raw) */
                case 0x06:
                        formation->pcm += channels;
                        break;
                /* MIDI Conformant */
                case 0x0d:
                        formation->midi = channels;
                        break;
                /* IEC 61937-3 to 7 */
                case 0x01:
                case 0x02:
                case 0x03:
                case 0x04:
                case 0x05:
                /* Multi Bit Linear Audio */
                case 0x07:      /* DVD-Audio */
                case 0x0c:      /* High Precision */
                /* One Bit Audio */
                case 0x08:      /* (Plain) Raw */
                case 0x09:      /* (Plain) SACD */
                case 0x0a:      /* (Encoded) Raw */
                case 0x0b:      /* (Encoded) SACD */
                /* SMPTE Time-Code conformant */
                case 0x0e:
                /* Sample Count */
                case 0x0f:
                /* Anciliary Data */
                case 0x10:
                /* Synchronization Stream (Stereo Raw audio) */
                case 0x40:
                /* Don't care */
                case 0xff:
                default:
                        return -ENXIO;  /* not supported */
                }
        }

        if (formation->pcm  > AM824_MAX_CHANNELS_FOR_PCM ||
            formation->midi > AM824_MAX_CHANNELS_FOR_MIDI)
                return -ENXIO;

        return 0;
}

static int
assume_stream_formats(struct snd_oxfw *oxfw, enum avc_general_plug_dir dir,
                      unsigned int pid, u8 *buf, unsigned int *len,
                      u8 **formats)
{
        struct snd_oxfw_stream_formation formation;
        unsigned int i, eid;
        int err;

        /* get format at current sampling rate */
        err = avc_stream_get_format_single(oxfw->unit, dir, pid, buf, len);
        if (err < 0) {
                dev_err(&oxfw->unit->device,
                "fail to get current stream format for isoc %s plug %d:%d\n",
                        (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : "out",
                        pid, err);
                goto end;
        }

        /* parse and set stream format */
        eid = 0;
        err = snd_oxfw_stream_parse_format(buf, &formation);
        if (err < 0)
                goto end;

        formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, *len,
                                    GFP_KERNEL);
        if (!formats[eid]) {
                err = -ENOMEM;
                goto end;
        }

        /* apply the format for each available sampling rate */
        for (i = 0; i < ARRAY_SIZE(oxfw_rate_table); i++) {
                if (formation.rate == oxfw_rate_table[i])
                        continue;

                err = avc_general_inquiry_sig_fmt(oxfw->unit,
                                                  oxfw_rate_table[i],
                                                  dir, pid);
                if (err < 0)
                        continue;

                eid++;
                formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, *len,
                                            GFP_KERNEL);
                if (formats[eid] == NULL) {
                        err = -ENOMEM;
                        goto end;
                }
                formats[eid][2] = avc_stream_rate_table[i];
        }

        err = 0;
        oxfw->assumed = true;
end:
        return err;
}

static int fill_stream_formats(struct snd_oxfw *oxfw,
                               enum avc_general_plug_dir dir,
                               unsigned short pid)
{
        u8 *buf, **formats;
        unsigned int len, eid = 0;
        struct snd_oxfw_stream_formation dummy;
        int err;

        buf = kmalloc(AVC_GENERIC_FRAME_MAXIMUM_BYTES, GFP_KERNEL);
        if (buf == NULL)
                return -ENOMEM;

        if (dir == AVC_GENERAL_PLUG_DIR_OUT)
                formats = oxfw->tx_stream_formats;
        else
                formats = oxfw->rx_stream_formats;

        /* get first entry */
        len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
        err = avc_stream_get_format_list(oxfw->unit, dir, 0, buf, &len, 0);
        if (err == -ENXIO) {
                /* LIST subfunction is not implemented */
                len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
                err = assume_stream_formats(oxfw, dir, pid, buf, &len,
                                            formats);
                goto end;
        } else if (err < 0) {
                dev_err(&oxfw->unit->device,
                        "fail to get stream format %d for isoc %s plug %d:%d\n",
                        eid, (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : "out",
                        pid, err);
                goto end;
        }

        /* LIST subfunction is implemented */
        while (eid < SND_OXFW_STREAM_FORMAT_ENTRIES) {
                /* The format is too short. */
                if (len < 3) {
                        err = -EIO;
                        break;
                }

                /* parse and set stream format */
                err = snd_oxfw_stream_parse_format(buf, &dummy);
                if (err < 0)
                        break;

                formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, len,
                                            GFP_KERNEL);
                if (!formats[eid]) {
                        err = -ENOMEM;
                        break;
                }

                /* get next entry */
                len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
                err = avc_stream_get_format_list(oxfw->unit, dir, 0,
                                                 buf, &len, ++eid);
                /* No entries remained. */
                if (err == -EINVAL) {
                        err = 0;
                        break;
                } else if (err < 0) {
                        dev_err(&oxfw->unit->device,
                        "fail to get stream format %d for isoc %s plug %d:%d\n",
                                eid, (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" :
                                                                        "out",
                                pid, err);
                        break;
                }
        }
end:
        kfree(buf);
        return err;
}

int snd_oxfw_stream_discover(struct snd_oxfw *oxfw)
{
        u8 plugs[AVC_PLUG_INFO_BUF_BYTES];
        struct snd_oxfw_stream_formation formation;
        u8 *format;
        unsigned int i;
        int err;

        /* the number of plugs for isoc in/out, ext in/out  */
        err = avc_general_get_plug_info(oxfw->unit, 0x1f, 0x07, 0x00, plugs);
        if (err < 0) {
                dev_err(&oxfw->unit->device,
                "fail to get info for isoc/external in/out plugs: %d\n",
                        err);
                goto end;
        } else if ((plugs[0] == 0) && (plugs[1] == 0)) {
                err = -ENXIO;
                goto end;
        }

        /* use oPCR[0] if exists */
        if (plugs[1] > 0) {
                err = fill_stream_formats(oxfw, AVC_GENERAL_PLUG_DIR_OUT, 0);
                if (err < 0) {
                        if (err != -ENXIO)
                                return err;

                        // The oPCR is not available for isoc communication.
                        err = 0;
                } else {
                        for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
                                format = oxfw->tx_stream_formats[i];
                                if (format == NULL)
                                        continue;
                                err = snd_oxfw_stream_parse_format(format,
                                                                   &formation);
                                if (err < 0)
                                        continue;

                                /* Add one MIDI port. */
                                if (formation.midi > 0)
                                        oxfw->midi_input_ports = 1;
                        }

                        oxfw->has_output = true;
                }
        }

        /* use iPCR[0] if exists */
        if (plugs[0] > 0) {
                err = fill_stream_formats(oxfw, AVC_GENERAL_PLUG_DIR_IN, 0);
                if (err < 0) {
                        if (err != -ENXIO)
                                return err;

                        // The iPCR is not available for isoc communication.
                        err = 0;
                } else {
                        for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
                                format = oxfw->rx_stream_formats[i];
                                if (format == NULL)
                                        continue;
                                err = snd_oxfw_stream_parse_format(format,
                                                                   &formation);
                                if (err < 0)
                                        continue;

                                /* Add one MIDI port. */
                                if (formation.midi > 0)
                                        oxfw->midi_output_ports = 1;
                        }

                        oxfw->has_input = true;
                }
        }
end:
        return err;
}

void snd_oxfw_stream_lock_changed(struct snd_oxfw *oxfw)
{
        oxfw->dev_lock_changed = true;
        wake_up(&oxfw->hwdep_wait);
}

int snd_oxfw_stream_lock_try(struct snd_oxfw *oxfw)
{
        int err;

        spin_lock_irq(&oxfw->lock);

        /* user land lock this */
        if (oxfw->dev_lock_count < 0) {
                err = -EBUSY;
                goto end;
        }

        /* this is the first time */
        if (oxfw->dev_lock_count++ == 0)
                snd_oxfw_stream_lock_changed(oxfw);
        err = 0;
end:
        spin_unlock_irq(&oxfw->lock);
        return err;
}

void snd_oxfw_stream_lock_release(struct snd_oxfw *oxfw)
{
        spin_lock_irq(&oxfw->lock);

        if (WARN_ON(oxfw->dev_lock_count <= 0))
                goto end;
        if (--oxfw->dev_lock_count == 0)
                snd_oxfw_stream_lock_changed(oxfw);
end:
        spin_unlock_irq(&oxfw->lock);
}