From 79d396583b856fc5bfa3470e0093e2cf204ef24c Mon Sep 17 00:00:00 2001 From: Simon Wilson Date: Wed, 25 May 2011 13:44:23 -0700 Subject: Initial contribution --- pcm.c | 351 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 351 insertions(+) create mode 100644 pcm.c (limited to 'pcm.c') diff --git a/pcm.c b/pcm.c new file mode 100644 index 0000000..71849a7 --- /dev/null +++ b/pcm.c @@ -0,0 +1,351 @@ +/* pcm.c +** +** Copyright 2011, The Android Open Source Project +** +** Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in the +** documentation and/or other materials provided with the distribution. +** * Neither the name of The Android Open Source Project nor the names of +** its contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** THIS SOFTWARE IS PROVIDED BY The Android Open Source Project ``AS IS'' AND +** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +** ARE DISCLAIMED. IN NO EVENT SHALL The Android Open Source Project BE LIABLE +** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +** SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH +** DAMAGE. +*/ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +#include +#define __force +#define __bitwise +#define __user +#include + +#include + +#define PARAM_MAX SNDRV_PCM_HW_PARAM_LAST_INTERVAL + +static inline int param_is_mask(int p) +{ + return (p >= SNDRV_PCM_HW_PARAM_FIRST_MASK) && + (p <= SNDRV_PCM_HW_PARAM_LAST_MASK); +} + +static inline int param_is_interval(int p) +{ + return (p >= SNDRV_PCM_HW_PARAM_FIRST_INTERVAL) && + (p <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL); +} + +static inline struct snd_interval *param_to_interval(struct snd_pcm_hw_params *p, int n) +{ + return &(p->intervals[n - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]); +} + +static inline struct snd_mask *param_to_mask(struct snd_pcm_hw_params *p, int n) +{ + return &(p->masks[n - SNDRV_PCM_HW_PARAM_FIRST_MASK]); +} + +static void param_set_mask(struct snd_pcm_hw_params *p, int n, unsigned int bit) +{ + if (bit >= SNDRV_MASK_MAX) + return; + if (param_is_mask(n)) { + struct snd_mask *m = param_to_mask(p, n); + m->bits[0] = 0; + m->bits[1] = 0; + m->bits[bit >> 5] |= (1 << (bit & 31)); + } +} + +static void param_set_min(struct snd_pcm_hw_params *p, int n, unsigned int val) +{ + if (param_is_interval(n)) { + struct snd_interval *i = param_to_interval(p, n); + i->min = val; + } +} + +static void param_set_max(struct snd_pcm_hw_params *p, int n, unsigned int val) +{ + if (param_is_interval(n)) { + struct snd_interval *i = param_to_interval(p, n); + i->max = val; + } +} + +static void param_set_int(struct snd_pcm_hw_params *p, int n, unsigned int val) +{ + if (param_is_interval(n)) { + struct snd_interval *i = param_to_interval(p, n); + i->min = val; + i->max = val; + i->integer = 1; + } +} + +static void param_init(struct snd_pcm_hw_params *p) +{ + int n; + memset(p, 0, sizeof(*p)); + for (n = SNDRV_PCM_HW_PARAM_FIRST_MASK; + n <= SNDRV_PCM_HW_PARAM_LAST_MASK; n++) { + struct snd_mask *m = param_to_mask(p, n); + m->bits[0] = ~0; + m->bits[1] = ~0; + } + for (n = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; + n <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; n++) { + struct snd_interval *i = param_to_interval(p, n); + i->min = 0; + i->max = ~0; + } +} + +#define PCM_ERROR_MAX 128 + +struct pcm { + int fd; + unsigned int flags; + int running:1; + int underruns; + unsigned int buffer_size; + char error[PCM_ERROR_MAX]; + struct pcm_config config; +}; + +unsigned int pcm_buffer_size(struct pcm *pcm) +{ + return pcm->buffer_size; +} + +const char* pcm_get_error(struct pcm *pcm) +{ + return pcm->error; +} + +static int oops(struct pcm *pcm, int e, const char *fmt, ...) +{ + va_list ap; + int sz; + + va_start(ap, fmt); + vsnprintf(pcm->error, PCM_ERROR_MAX, fmt, ap); + va_end(ap); + sz = strlen(pcm->error); + + if (errno) + snprintf(pcm->error + sz, PCM_ERROR_MAX - sz, + ": %s", strerror(e)); + return -1; +} + +int pcm_write(struct pcm *pcm, void *data, unsigned int count) +{ + struct snd_xferi x; + + if (pcm->flags & PCM_IN) + return -EINVAL; + + x.buf = data; + x.frames = count / (pcm->config.channels * 2); /* TODO: handle 32bit */ + + for (;;) { + if (!pcm->running) { + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_PREPARE)) + return oops(pcm, errno, "cannot prepare channel"); + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x)) + return oops(pcm, errno, "cannot write initial data"); + pcm->running = 1; + return 0; + } + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x)) { + pcm->running = 0; + if (errno == EPIPE) { + /* we failed to make our window -- try to restart */ + pcm->underruns++; + continue; + } + return oops(pcm, errno, "cannot write stream data"); + } + return 0; + } +} + +int pcm_read(struct pcm *pcm, void *data, unsigned int count) +{ + struct snd_xferi x; + + if (!(pcm->flags & PCM_IN)) + return -EINVAL; + + x.buf = data; + x.frames = count / (pcm->config.channels * 2); /* TODO: handle 32bit */ + + for (;;) { + if (!pcm->running) { + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_PREPARE)) + return oops(pcm, errno, "cannot prepare channel"); + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_START)) + return oops(pcm, errno, "cannot start channel"); + pcm->running = 1; + } + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_READI_FRAMES, &x)) { + pcm->running = 0; + if (errno == EPIPE) { + /* we failed to make our window -- try to restart */ + pcm->underruns++; + continue; + } + return oops(pcm, errno, "cannot read stream data"); + } + return 0; + } +} + +static struct pcm bad_pcm = { + .fd = -1, +}; + +int pcm_close(struct pcm *pcm) +{ + if (pcm == &bad_pcm) + return 0; + + if (pcm->fd >= 0) + close(pcm->fd); + pcm->running = 0; + pcm->buffer_size = 0; + pcm->fd = -1; + return 0; +} + +static unsigned int pcm_format_to_alsa(enum pcm_format format) +{ + switch (format) { + case PCM_FORMAT_S32_LE: + return SNDRV_PCM_FORMAT_S32_LE; + default: + case PCM_FORMAT_S16_LE: + return SNDRV_PCM_FORMAT_S16_LE; + }; +} + +static unsigned int pcm_format_to_bits(enum pcm_format format) +{ + switch (format) { + case PCM_FORMAT_S32_LE: + return 32; + default: + case PCM_FORMAT_S16_LE: + return 16; + }; +} + +struct pcm *pcm_open(unsigned int device, unsigned int flags, struct pcm_config *config) +{ + const char *dname; + struct pcm *pcm; + struct snd_pcm_info info; + struct snd_pcm_hw_params params; + struct snd_pcm_sw_params sparams; + + pcm = calloc(1, sizeof(struct pcm)); + if (!pcm || !config) + return &bad_pcm; /* TODO: could support default config here */ + + pcm->config = *config; + + if (flags & PCM_IN) { + dname = "/dev/snd/pcmC0D0c"; + } else { + dname = "/dev/snd/pcmC0D0p"; + } + + pcm->flags = flags; + pcm->fd = open(dname, O_RDWR); + if (pcm->fd < 0) { + oops(pcm, errno, "cannot open device '%s'"); + return pcm; + } + + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_INFO, &info)) { + oops(pcm, errno, "cannot get info - %s"); + goto fail; + } + + param_init(¶ms); + param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS, + SNDRV_PCM_ACCESS_RW_INTERLEAVED); + param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_FORMAT, + pcm_format_to_alsa(config->format)); + param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_SUBFORMAT, + SNDRV_PCM_SUBFORMAT_STD); + param_set_min(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_SAMPLE_BITS, + pcm_format_to_bits(config->format)); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_FRAME_BITS, + pcm_format_to_bits(config->format) * config->channels); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_CHANNELS, + config->channels); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_RATE, config->rate); + + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, ¶ms)) { + oops(pcm, errno, "cannot set hw params"); + goto fail; + } + + memset(&sparams, 0, sizeof(sparams)); + sparams.tstamp_mode = SNDRV_PCM_TSTAMP_NONE; + sparams.period_step = 1; + sparams.avail_min = 1; + sparams.start_threshold = config->period_count * config->period_size; + sparams.stop_threshold = config->period_count * config->period_size; + sparams.xfer_align = config->period_size / 2; /* needed for old kernels */ + sparams.silence_size = 0; + sparams.silence_threshold = 0; + + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) { + oops(pcm, errno, "cannot set sw params"); + goto fail; + } + + pcm->buffer_size = config->period_count * config->period_size; + pcm->underruns = 0; + return pcm; + +fail: + close(pcm->fd); + pcm->fd = -1; + return pcm; +} + +int pcm_is_ready(struct pcm *pcm) +{ + return pcm->fd >= 0; +} -- cgit v1.2.3