libsigrok/hardware/alsa/protocol.c

403 lines
12 KiB
C

/*
* This file is part of the libsigrok project.
*
* Copyright (C) 2011 Daniel Ribeiro <drwyrm@gmail.com>
* Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
* Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@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
*/
#include "libsigrok.h"
#include "libsigrok-internal.h"
#include "protocol.h"
/*
* There is no way to get a list of supported samplerates from ALSA. We could
* use the 'plughw' interface of ALSA, in which case any format and/or
* samplerate conversion would be performed by ALSA. However, we are interested
* in the hardware capabilities, and have the infrastructure in sigrok to do so.
* We therefore use the 'hw' interface. The downside is that the code gets a
* little bulkier, as we have to keep track of the hardware capabilities, and
* only use those that the hardware supports. Case in point, ALSA will not give
* us a list of capabilities; we have to test for each one individually. Hence,
* we keep lists of the capabilities we are interested in.
*/
static const unsigned int rates[] = {
5512,
8000,
11025,
12000,
16000,
22050,
24000,
32000,
44100,
48000,
64000,
88200,
96000,
176400,
192000,
384000,
768000, /* Yes, there are sound cards that go this high. */
};
static void alsa_scan_handle_dev(GSList **devices,
const char *cardname, const char *alsaname,
struct sr_dev_driver *di,
snd_pcm_info_t *pcminfo)
{
struct drv_context *drvc = NULL;
struct sr_dev_inst *sdi = NULL;
struct dev_context *devc = NULL;
struct sr_probe *probe;
int ret;
unsigned int i, offset, channels, minrate, maxrate, rate;
uint64_t hwrates[ARRAY_SIZE(rates)];
uint64_t *devrates = NULL;
snd_pcm_t *temp_handle = NULL;
snd_pcm_hw_params_t *hw_params = NULL;
char p_name[32];
drvc = di->priv;
/*
* Get hardware parameters:
* The number of channels, for example, are our sigrok probes. Getting
* this information needs a detour. We need to open the device, then
* query it and/or test different parameters. A side-effect of is that
* we create a snd_pcm_hw_params_t object. We take advantage of the
* situation, and pass this object in our dev_context->hw_params,
* eliminating the need to free() it and malloc() it later.
*/
ret = snd_pcm_open(&temp_handle, alsaname, SND_PCM_STREAM_CAPTURE, 0);
if (ret < 0) {
sr_err("Cannot open device: %s.", snd_strerror(ret));
goto scan_error_cleanup;
}
ret = snd_pcm_hw_params_malloc(&hw_params);
if (ret < 0) {
sr_err("Error allocating hardware parameter structure: %s.",
snd_strerror(ret));
goto scan_error_cleanup;
}
ret = snd_pcm_hw_params_any(temp_handle, hw_params);
if (ret < 0) {
sr_err("Error initializing hardware parameter structure: %s.",
snd_strerror(ret));
goto scan_error_cleanup;
}
snd_pcm_hw_params_get_channels_max(hw_params, &channels);
/*
* We need to test if each samplerate between min and max is supported.
* Unfortunately, ALSA won't just throw a list at us.
*/
snd_pcm_hw_params_get_rate_min(hw_params, &minrate, 0);
snd_pcm_hw_params_get_rate_max(hw_params, &maxrate, 0);
for (i = 0, offset = 0; i < ARRAY_SIZE(rates); i++) {
rate = rates[i];
if (rate < minrate)
continue;
if (rate > maxrate)
break;
ret = snd_pcm_hw_params_test_rate(temp_handle, hw_params,
rate, 0);
if (ret >= 0)
hwrates[offset++] = rate;
}
hwrates[offset++] = 0;
if ((ret = snd_pcm_close(temp_handle)) < 0)
sr_err("Failed to close device: %s.", snd_strerror(ret));
temp_handle = NULL;
/*
* Now we are done querying the hardware parameters.
* If we made it here, we know everything we want to know, and it's
* time to create our sigrok device.
*/
sr_info("Device %s has %d channels.", alsaname, channels);
if (!(sdi = sr_dev_inst_new(0, SR_ST_INACTIVE, "ALSA:",
cardname, snd_pcm_info_get_name(pcminfo)))) {
sr_err("Failed to create device instance.");
goto scan_error_cleanup;
}
if (!(devc = g_try_malloc0(sizeof(struct dev_context)))) {
sr_err("Device context malloc failed.");
goto scan_error_cleanup;
}
if (!(devrates = g_try_malloc(offset * sizeof(uint64_t)))) {
sr_err("Samplerate list malloc failed.");
goto scan_error_cleanup;
}
devc->hwdev = g_strdup(alsaname);
devc->num_probes = channels;
devc->hw_params = hw_params;
memcpy(devrates, hwrates, offset * sizeof(uint64_t));
devc->samplerates = devrates;
sdi->priv = devc;
sdi->driver = di;
for (i = 0; i < devc->num_probes; i++) {
snprintf(p_name, sizeof(p_name), "Ch_%d", i);
if (!(probe = sr_probe_new(i, SR_PROBE_ANALOG, TRUE, p_name)))
goto scan_error_cleanup;
sdi->probes = g_slist_append(sdi->probes, probe);
}
drvc->instances = g_slist_append(drvc->instances, sdi);
*devices = g_slist_append(*devices, sdi);
return;
scan_error_cleanup:
if (devc) {
if (devc->hwdev)
g_free(devc->hwdev);
g_free(devc);
}
if (devrates)
g_free(devrates);
if (sdi)
sr_dev_inst_free(sdi);
if (hw_params)
snd_pcm_hw_params_free(hw_params);
if (temp_handle)
if ((ret = snd_pcm_close(temp_handle)) < 0) {
sr_err("Failed to close device: %s.",
snd_strerror(ret));
}
}
/**
* Scan all alsa devices, and translate them to sigrok devices.
*
* Each alsa device (not alsa card) gets its own sigrok device.
*
* For example,
* hw:1,0 == sigrok device 0
* hw:1,1 == sigrok device 1
* hw:2,0 == sigrok device 2
* hw:2,1 == sigrok device 3
* hw:2,2 == sigrok device 4
* [...]
*
* We don't currently look at alsa subdevices. We only use subdevice 0.
* Every input device will have its own channels (left, right, etc). Each of
* those channels gets mapped to a different sigrok probe. A device with 4
* channels will have 4 probes from sigrok's perspective.
*/
SR_PRIV GSList *alsa_scan(GSList *options, struct sr_dev_driver *di)
{
GSList *devices = NULL;
snd_ctl_t *handle;
int card, ret, dev;
snd_ctl_card_info_t *info;
snd_pcm_info_t *pcminfo;
const char *cardname;
char hwcard[32], hwdev[32];
/* TODO */
(void)options;
if ((ret = snd_ctl_card_info_malloc(&info)) < 0) {
sr_dbg("Failed to malloc card info: %s.", snd_strerror(ret));
return NULL;
}
if ((ret = snd_pcm_info_malloc(&pcminfo) < 0)) {
sr_dbg("Cannot malloc pcm info: %s.", snd_strerror(ret));
return NULL;
}
card = -1;
while (snd_card_next(&card) >= 0 && card >= 0) {
snprintf(hwcard, sizeof(hwcard), "hw:%d", card);
if ((ret = snd_ctl_open(&handle, hwcard, 0)) < 0) {
sr_dbg("Cannot open (%d): %s.", card, snd_strerror(ret));
continue;
}
if ((ret = snd_ctl_card_info(handle, info)) < 0) {
sr_dbg("Cannot get hardware info (%d): %s.",
card, snd_strerror(ret));
if ((ret = snd_ctl_close(handle)) < 0) {
sr_dbg("Cannot close device (%d): %s.",
card, snd_strerror(ret));
}
continue;
}
dev = -1;
while (snd_ctl_pcm_next_device(handle, &dev) >= 0 && dev >= 0) {
snprintf(hwdev, sizeof(hwdev), "%s,%d", hwcard, dev);
/*
* TODO: We always use subdevice 0, but we have yet to
* explore the possibilities opened up by other
* subdevices. Most hardware only has subdevice 0.
*/
snd_pcm_info_set_device(pcminfo, dev);
snd_pcm_info_set_subdevice(pcminfo, 0);
snd_pcm_info_set_stream(pcminfo,
SND_PCM_STREAM_CAPTURE);
if ((ret = snd_ctl_pcm_info(handle, pcminfo)) < 0) {
sr_dbg("Cannot get device info (%s): %s.",
hwdev, snd_strerror(ret));
continue;
}
cardname = snd_ctl_card_info_get_name(info);
sr_info("card %d: %s [%s], device %d: %s [%s]",
card, snd_ctl_card_info_get_id(info), cardname,
dev, snd_pcm_info_get_id(pcminfo),
snd_pcm_info_get_name(pcminfo));
alsa_scan_handle_dev(&devices, cardname, hwdev,
di, pcminfo);
}
if ((ret = snd_ctl_close(handle)) < 0) {
sr_dbg("Cannot close device (%d): %s.",
card, snd_strerror(ret));
}
}
snd_pcm_info_free(pcminfo);
snd_ctl_card_info_free(info);
return devices;
}
/**
* Set the samplerate of the ALSA device.
*
* Changes the samplerate of the given ALSA device if the specified samplerate
* is supported by the hardware.
*
* The new samplerate is recorded, but it is not applied to the hardware. The
* samplerate is applied to the hardware only when acquisition is started via
* dev_acquisition_start(), and cannot be changed during acquisition. To change
* the samplerate, several steps are needed:
*
* 1) If acquisition is running, it must first be stopped.
* 2) dev_config_set() must be called with the new samplerate.
* 3) When starting a new acquisition, the new samplerate is applied.
*
*/
SR_PRIV int alsa_set_samplerate(const struct sr_dev_inst *sdi,
uint64_t newrate)
{
struct dev_context *devc;
size_t i;
uint64_t rate = 0;
if (!(devc = sdi->priv))
return SR_ERR_ARG;
i = 0;
do {
if (newrate == devc->samplerates[i]) {
rate = newrate;
break;
}
} while (devc->samplerates[i++] != 0);
if (!rate) {
sr_err("Sample rate %" PRIu64 " not supported.", newrate);
return SR_ERR_ARG;
}
devc->cur_samplerate = rate;
return SR_OK;
}
SR_PRIV int alsa_receive_data(int fd, int revents, void *cb_data)
{
struct sr_dev_inst *sdi;
struct dev_context *devc;
struct sr_datafeed_packet packet;
struct sr_datafeed_analog analog;
int16_t inbuf[4096];
int i, x, count, offset, samples_to_get;
int16_t tmp16;
const float s16norm = 1 / (float)(1 << 15);
(void)fd;
(void)revents;
sdi = cb_data;
devc = sdi->priv;
memset(&analog, 0, sizeof(struct sr_datafeed_analog));
memset(inbuf, 0, sizeof(inbuf));
samples_to_get = MIN(4096 / 4, devc->limit_samples);
sr_spew("Getting %d samples from audio device.", samples_to_get);
count = snd_pcm_readi(devc->capture_handle, inbuf, samples_to_get);
if (count < 0) {
sr_err("Failed to read samples: %s.", snd_strerror(count));
return FALSE;
} else if (count != samples_to_get) {
sr_spew("Only got %d/%d samples.", count, samples_to_get);
}
analog.data = g_try_malloc0(count * sizeof(float) * devc->num_probes);
if (!analog.data) {
sr_err("Failed to malloc sample buffer.");
return FALSE;
}
offset = 0;
/*
* It's impossible to know what voltage levels the soundcard handles.
* Some handle 0 dBV rms, some 0dBV peak-to-peak, +4dbmW (600 ohm), etc
* Each of these corresponds to a different voltage, and there is no
* mechanism to determine this voltage. The best solution is to send all
* audio data as a normalized float, and let the frontend or user worry
* about the calibration.
*/
for (i = 0; i < count; i += devc->num_probes) {
for (x = 0; x < devc->num_probes; x++) {
tmp16 = inbuf[i + x];
analog.data[offset++] = tmp16 * s16norm;
}
}
/* Send a sample packet with the analog values. */
analog.probes = sdi->probes;
analog.num_samples = count;
analog.mq = SR_MQ_VOLTAGE; /* FIXME */
analog.unit = SR_UNIT_VOLT; /* FIXME */
packet.type = SR_DF_ANALOG;
packet.payload = &analog;
sr_session_send(devc->cb_data, &packet);
g_free(analog.data);
devc->num_samples += count;
/* Stop acquisition if we acquired enough samples. */
if (devc->limit_samples && devc->num_samples >= devc->limit_samples) {
sr_info("Requested number of samples reached.");
sdi->driver->dev_acquisition_stop(sdi, cb_data);
}
return TRUE;
}