Initial contribution

1 files changed, 351 insertions, 0 deletions

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 <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/time.h>
+
+#include <linux/ioctl.h>
+#define __force
+#define __bitwise
+#define __user
+#include <sound/asound.h>
+
+#include <tinyalsa/asoundlib.h>
+
+#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(&params);
+    param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
+                   SNDRV_PCM_ACCESS_RW_INTERLEAVED);
+    param_set_mask(&params, SNDRV_PCM_HW_PARAM_FORMAT,
+                   pcm_format_to_alsa(config->format));
+    param_set_mask(&params, SNDRV_PCM_HW_PARAM_SUBFORMAT,
+                   SNDRV_PCM_SUBFORMAT_STD);
+    param_set_min(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size);
+    param_set_int(&params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
+                  pcm_format_to_bits(config->format));
+    param_set_int(&params, SNDRV_PCM_HW_PARAM_FRAME_BITS,
+                  pcm_format_to_bits(config->format) * config->channels);
+    param_set_int(&params, SNDRV_PCM_HW_PARAM_CHANNELS,
+                  config->channels);
+    param_set_int(&params, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count);
+    param_set_int(&params, SNDRV_PCM_HW_PARAM_RATE, config->rate);
+
+    if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, &params)) {
+        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;
+}