alsa.c

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/*
 * This file is part of the sigrok project.
 *
 * Copyright (C) 2011 Daniel Ribeiro <drwyrm@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

/* Note: This driver doesn't compile, analog support in sigrok is WIP. */

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <alsa/asoundlib.h>
#include "sigrok.h"
#include "sigrok-internal.h"

#define NUM_PROBES 2
#define SAMPLE_WIDTH 16
#define AUDIO_DEV "plughw:0,0"

struct sr_analog_probe {
        uint8_t att;
        uint8_t res;    /* Needs to be a power of 2, FIXME */
        uint16_t val;   /* Max hardware ADC width is 16bits */
};

struct sr_analog_sample {
        uint8_t num_probes; /* Max hardware probes is 256 */
        struct sr_analog_probe probes[];
};

static int hwcaps[] = {
        SR_HWCAP_SAMPLERATE,
        SR_HWCAP_LIMIT_SAMPLES,
        SR_HWCAP_CONTINUOUS,
};

/* TODO: Which probe names/numbers to use? */
static const char *probe_names[NUM_PROBES + 1] = {
        "0",
        "1",
        NULL,
};

static GSList *dev_insts = NULL;

/* Private, per-device-instance driver context. */
struct context {
        uint64_t cur_rate;
        uint64_t limit_samples;
        snd_pcm_t *capture_handle;
        snd_pcm_hw_params_t *hw_params;
        void *session_dev_id;
};

static int hw_init(const char *devinfo)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;

        /* Avoid compiler warnings. */
        (void)devinfo;

        if (!(ctx = g_try_malloc0(sizeof(struct context)))) {
                sr_err("alsa: %s: ctx malloc failed", __func__);
                return 0;
        }

        if (!(sdi = sr_dev_inst_new(0, SR_ST_ACTIVE, "alsa", NULL, NULL))) {
                sr_err("alsa: %s: sdi was NULL", __func__);
                goto free_ctx;
        }

        sdi->priv = ctx;

        dev_insts = g_slist_append(dev_insts, sdi);

        return 1;

free_ctx:
        g_free(ctx);
        return 0;
}

static int hw_dev_open(int dev_index)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;
        int ret;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
                return SR_ERR;
        ctx = sdi->priv;

        ret = snd_pcm_open(&ctx->capture_handle, AUDIO_DEV,
                           SND_PCM_STREAM_CAPTURE, 0);
        if (ret < 0) {
                sr_err("alsa: can't open audio device %s (%s)", AUDIO_DEV,
                       snd_strerror(ret));
                return SR_ERR;
        }

        ret = snd_pcm_hw_params_malloc(&ctx->hw_params);
        if (ret < 0) {
                sr_err("alsa: can't allocate hardware parameter structure (%s)",
                       snd_strerror(ret));
                return SR_ERR;
        }

        ret = snd_pcm_hw_params_any(ctx->capture_handle, ctx->hw_params);
        if (ret < 0) {
                sr_err("alsa: can't initialize hardware parameter structure "
                       "(%s)", snd_strerror(ret));
                return SR_ERR;
        }

        return SR_OK;
}

static int hw_dev_close(int dev_index)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
                sr_err("alsa: %s: sdi was NULL", __func__);
                return SR_ERR_BUG;
        }

        if (!(ctx = sdi->priv)) {
                sr_err("alsa: %s: sdi->priv was NULL", __func__);
                return SR_ERR_BUG;
        }

        // TODO: Return values of snd_*?
        if (ctx->hw_params)
                snd_pcm_hw_params_free(ctx->hw_params);
        if (ctx->capture_handle)
                snd_pcm_close(ctx->capture_handle);

        return SR_OK;
}

static int hw_cleanup(void)
{
        struct sr_dev_inst *sdi;

        if (!(sdi = sr_dev_inst_get(dev_insts, 0))) {
                sr_err("alsa: %s: sdi was NULL", __func__);
                return SR_ERR_BUG;
        }

        sr_dev_inst_free(sdi);

        return SR_OK;
}

static void *hw_dev_info_get(int dev_index, int dev_info_id)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;
        void *info = NULL;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
                return NULL;
        ctx = sdi->priv;

        switch (dev_info_id) {
        case SR_DI_INST:
                info = sdi;
                break;
        case SR_DI_NUM_PROBES:
                info = GINT_TO_POINTER(NUM_PROBES);
                break;
        case SR_DI_PROBE_NAMES:
                info = probe_names;
                break;
        case SR_DI_CUR_SAMPLERATE:
                info = &ctx->cur_rate;
                break;
        // case SR_DI_PROBE_TYPE:
        //      info = GINT_TO_POINTER(SR_PROBE_TYPE_ANALOG);
        //      break;
        }

        return info;
}

static int hw_dev_status_get(int dev_index)
{
        /* Avoid compiler warnings. */
        dev_index = dev_index;

        return SR_ST_ACTIVE;
}

static int *hw_hwcap_get_all(void)
{
        return hwcaps;
}

static int hw_dev_config_set(int dev_index, int hwcap, void *value)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
                return SR_ERR;
        ctx = sdi->priv;

        switch (hwcap) {
        case SR_HWCAP_PROBECONFIG:
                return SR_OK;
        case SR_HWCAP_SAMPLERATE:
                ctx->cur_rate = *(uint64_t *)value;
                return SR_OK;
        case SR_HWCAP_LIMIT_SAMPLES:
                ctx->limit_samples = *(uint64_t *)value;
                return SR_OK;
        default:
                return SR_ERR;
        }
}

static int receive_data(int fd, int revents, void *cb_data)
{
        struct sr_dev_inst *sdi = cb_data;
        struct context *ctx = sdi->priv;
        struct sr_datafeed_packet packet;
        struct sr_analog_sample *sample;
        unsigned int sample_size = sizeof(struct sr_analog_sample) +
                (NUM_PROBES * sizeof(struct sr_analog_probe));
        char *outb;
        char inb[4096];
        int i, x, count;

        fd = fd;
        revents = revents;

        do {
                memset(inb, 0, sizeof(inb));
                count = snd_pcm_readi(ctx->capture_handle, inb,
                        MIN(4096 / 4, ctx->limit_samples));
                if (count < 1) {
                        sr_err("alsa: Failed to read samples");
                        return FALSE;
                }

                if (!(outb = g_try_malloc(sample_size * count))) {
                        sr_err("alsa: %s: outb malloc failed", __func__);
                        return FALSE;
                }

                for (i = 0; i < count; i++) {
                        sample = (struct sr_analog_sample *)
                                                (outb + (i * sample_size));
                        sample->num_probes = NUM_PROBES;

                        for (x = 0; x < NUM_PROBES; x++) {
                                sample->probes[x].val =
                                        *(uint16_t *)(inb + (i * 4) + (x * 2));
                                sample->probes[x].val &= ((1 << 16) - 1);
                                sample->probes[x].res = 16;
                        }
                }

                packet.type = SR_DF_ANALOG;
                packet.length = count * sample_size;
                packet.unitsize = sample_size;
                packet.payload = outb;
                sr_session_send(sdi, &packet);
                g_free(outb);
                ctx->limit_samples -= count;

        } while (ctx->limit_samples > 0);

        packet.type = SR_DF_END;
        sr_session_send(sdi, &packet);

        return TRUE;
}

static int hw_dev_acquisition_start(int dev_index, void *cb_data)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;
        struct sr_datafeed_packet packet;
        struct sr_datafeed_header header;
        struct pollfd *ufds;
        int count;
        int ret;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
                return SR_ERR;
        ctx = sdi->priv;

        ret = snd_pcm_hw_params_set_access(ctx->capture_handle,
                        ctx->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
        if (ret < 0) {
                sr_err("alsa: can't set access type (%s)", snd_strerror(ret));
                return SR_ERR;
        }

        /* FIXME: Hardcoded for 16bits */
        ret = snd_pcm_hw_params_set_format(ctx->capture_handle,
                        ctx->hw_params, SND_PCM_FORMAT_S16_LE);
        if (ret < 0) {
                sr_err("alsa: can't set sample format (%s)", snd_strerror(ret));
                return SR_ERR;
        }

        ret = snd_pcm_hw_params_set_rate_near(ctx->capture_handle,
                        ctx->hw_params, (unsigned int *)&ctx->cur_rate, 0);
        if (ret < 0) {
                sr_err("alsa: can't set sample rate (%s)", snd_strerror(ret));
                return SR_ERR;
        }

        ret = snd_pcm_hw_params_set_channels(ctx->capture_handle,
                        ctx->hw_params, NUM_PROBES);
        if (ret < 0) {
                sr_err("alsa: can't set channel count (%s)", snd_strerror(ret));
                return SR_ERR;
        }

        ret = snd_pcm_hw_params(ctx->capture_handle, ctx->hw_params);
        if (ret < 0) {
                sr_err("alsa: can't set parameters (%s)", snd_strerror(ret));
                return SR_ERR;
        }

        ret = snd_pcm_prepare(ctx->capture_handle);
        if (ret < 0) {
                sr_err("alsa: can't prepare audio interface for use (%s)",
                       snd_strerror(ret));
                return SR_ERR;
        }

        count = snd_pcm_poll_descriptors_count(ctx->capture_handle);
        if (count < 1) {
                sr_err("alsa: Unable to obtain poll descriptors count");
                return SR_ERR;
        }

        if (!(ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
                sr_err("alsa: %s: ufds malloc failed", __func__);
                return SR_ERR_MALLOC;
        }

        ret = snd_pcm_poll_descriptors(ctx->capture_handle, ufds, count);
        if (ret < 0) {
                sr_err("alsa: Unable to obtain poll descriptors (%s)",
                       snd_strerror(ret));
                g_free(ufds);
                return SR_ERR;
        }

        ctx->session_dev_id = cb_data;
        sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);

        packet.type = SR_DF_HEADER;
        packet.length = sizeof(struct sr_datafeed_header);
        packet.payload = (unsigned char *)&header;
        header.feed_version = 1;
        gettimeofday(&header.starttime, NULL);
        header.samplerate = ctx->cur_rate;
        header.num_analog_probes = NUM_PROBES;
        header.num_logic_probes = 0;
        header.protocol_id = SR_PROTO_RAW;
        sr_session_send(cb_data, &packet);
        g_free(ufds);

        return SR_OK;
}

/* TODO: This stops acquisition on ALL devices, ignoring dev_index. */
static int hw_dev_acquisition_stop(int dev_index, void *cb_data)
{
        /* Avoid compiler warnings. */
        (void)dev_index;
        (void)cb_data;

        return SR_OK;
}

SR_PRIV struct sr_dev_driver alsa_driver_info = {
        .name = "alsa",
        .longname = "ALSA driver",
        .api_version = 1,
        .init = hw_init,
        .cleanup = hw_cleanup,
        .dev_open = hw_dev_open,
        .dev_close = hw_dev_close,
        .dev_info_get = hw_dev_info_get,
        .dev_status_get = hw_dev_status_get,
        .hwcap_get_all = hw_hwcap_get_all,
        .dev_config_set = hw_dev_config_set,
        .dev_acquisition_start = hw_dev_acquisition_start,
        .dev_acquisition_stop = hw_dev_acquisition_stop,
};