1 files changed, 332 insertions, 0 deletions
diff --git a/examples/plugins/sample_pcm_plugin.c b/examples/plugins/sample_pcm_plugin.c
new file mode 100644
index 0000000..40bf684
--- /dev/null
+++ b/examples/plugins/sample_pcm_plugin.c
@@ -0,0 +1,332 @@
+/* sample_mixer_plugin.c
+**
+** Copyright (c) 2021, The Linux Foundation. All rights reserved.
+**
+** 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 Linux Foundation 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 "AS IS" AND ANY EXPRESS OR IMPLIED
+** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+** ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+** 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 <errno.h>
+#include <limits.h>
+#include <sys/time.h>
+#include <sys/mman.h>
+#include <sound/asound.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <strings.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <tinyalsa/plugin.h>
+#include <tinyalsa/asoundlib.h>
+
+/* 2 words of uint32_t = 64 bits of mask */
+#define PCM_MASK_SIZE (2)
+#define PCM_FORMAT_BIT(x) (1ULL << x)
+
+struct sample_pcm_priv {
+    FILE *fptr;
+    int session_id;
+    int channels;
+    int bitwidth;
+    int sample_rate;
+    unsigned int period_size;
+    snd_pcm_uframes_t total_size_frames;
+};
+
+struct pcm_plugin_hw_constraints sample_pcm_constrs = {
+    .access = 0,
+    .format = 0,
+    .bit_width = {
+        .min = 16,
+        .max = 32,
+    },
+    .channels = {
+        .min = 1,
+        .max = 8,
+    },
+    .rate = {
+        .min = 8000,
+        .max = 384000,
+    },
+    .periods = {
+        .min = 1,
+        .max = 8,
+    },
+    .period_bytes = {
+        .min = 96,
+        .max = 122880,
+    },
+};
+
+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 int param_is_interval(int p)
+{
+    return (p >= SNDRV_PCM_HW_PARAM_FIRST_INTERVAL) &&
+        (p <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL);
+}
+
+static unsigned int param_get_int(struct snd_pcm_hw_params *p, int n)
+{
+    if (param_is_interval(n)) {
+        struct snd_interval *i = param_to_interval(p, n);
+        if (i->integer)
+            return i->max;
+    }
+    return 0;
+}
+
+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 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 snd_mask_val(const struct snd_mask *mask)
+{
+    int i;
+    for (i = 0; i < PCM_MASK_SIZE; i++) {
+        if (mask->bits[i])
+            return ffs(mask->bits[i]) + (i << 5) - 1;
+    }
+    return 0;
+}
+
+static int alsaformat_to_bitwidth(int format)
+{
+    switch (format) {
+    case SNDRV_PCM_FORMAT_S32_LE:
+    case SNDRV_PCM_FORMAT_S24_LE:
+        return 32;
+    case SNDRV_PCM_FORMAT_S8:
+        return 8;
+    case SNDRV_PCM_FORMAT_S24_3LE:
+        return 24;
+    default:
+    case SNDRV_PCM_FORMAT_S16_LE:
+        return 16;
+    };
+}
+
+static int param_get_mask_val(struct snd_pcm_hw_params *p,
+                                        int n)
+{
+    if (param_is_mask(n)) {
+        struct snd_mask *m = param_to_mask(p, n);
+        int val = snd_mask_val(m);
+
+        return alsaformat_to_bitwidth(val);
+    }
+    return 0;
+}
+
+static int sample_session_open(int sess_id, unsigned int mode, struct sample_pcm_priv *priv)
+{
+     char fname[128];
+
+     snprintf(fname, 128, "sample_pcm_data_%d.raw", sess_id);
+     priv->fptr = fopen(fname,"rwb+");
+     if (priv->fptr == NULL) {
+         return -EIO;
+     }
+     rewind(priv->fptr);
+     return 0;
+}
+
+
+static int sample_session_write(struct sample_pcm_priv *priv, void *buff, size_t count)
+{
+    uint8_t *data = (uint8_t *)buff;
+    size_t len;
+
+    len  = fwrite(buff, 1, count, priv->fptr);
+
+    if (len != count)
+        return -EIO;
+
+    return 0;
+}
+
+static int sample_pcm_hw_params(struct pcm_plugin *plugin,
+                             struct snd_pcm_hw_params *params)
+{
+    struct sample_pcm_priv *priv = plugin->priv;
+
+    priv->sample_rate = param_get_int(params, SNDRV_PCM_HW_PARAM_RATE);
+    priv->channels = param_get_int(params, SNDRV_PCM_HW_PARAM_CHANNELS);
+    priv->bitwidth = param_get_mask_val(params, SNDRV_PCM_HW_PARAM_FORMAT);
+
+    return 0;
+}
+
+static int sample_pcm_sw_params(struct pcm_plugin *plugin,
+                             struct snd_pcm_sw_params *sparams)
+{
+    return 0;
+}
+
+static int sample_pcm_sync_ptr(struct pcm_plugin *plugin,
+                            struct snd_pcm_sync_ptr *sync_ptr)
+{
+    return 0;
+}
+
+static int sample_pcm_writei_frames(struct pcm_plugin *plugin, struct snd_xferi *x)
+{
+    struct sample_pcm_priv *priv = plugin->priv;
+    void *buff;
+    size_t count;
+
+    buff = x->buf;
+    count = x->frames * (priv->channels * (priv->bitwidth) / 8);
+
+    return sample_session_write(priv, buff, count);
+}
+
+static int sample_pcm_readi_frames(struct pcm_plugin *plugin, struct snd_xferi *x)
+{
+    return 0;
+}
+
+static int sample_pcm_ttstamp(struct pcm_plugin *plugin, int *tstamp)
+{
+    return 0;
+}
+
+static int sample_pcm_prepare(struct pcm_plugin *plugin)
+{
+    return 0;
+}
+
+static int sample_pcm_start(struct pcm_plugin *plugin)
+{
+    return 0;
+}
+
+static int sample_pcm_drop(struct pcm_plugin *plugin)
+{
+    return 0;
+}
+
+static int sample_pcm_close(struct pcm_plugin *plugin)
+{
+    struct sample_pcm_priv *priv = plugin->priv;
+    int ret = 0;
+
+    fclose(priv->fptr);
+    free(plugin->priv);
+    free(plugin);
+
+    return ret;
+}
+
+static int sample_pcm_poll(struct pcm_plugin *plugin, struct pollfd *pfd,
+        nfds_t nfds, int timeout)
+{
+    return 0;
+}
+
+static void* sample_pcm_mmap(struct pcm_plugin *plugin, void *addr, size_t length, int prot,
+                               int flags, off_t offset)
+{
+    return MAP_FAILED;
+}
+
+static int sample_pcm_munmap(struct pcm_plugin *plugin, void *addr, size_t length)
+{
+    return 0;
+}
+
+int sample_pcm_open(struct pcm_plugin **plugin, unsigned int card,
+                    unsigned int device, unsigned int mode)
+{
+    struct pcm_plugin *sample_pcm_plugin;
+    struct sample_pcm_priv *priv;
+    int ret = 0, session_id = device;
+
+    sample_pcm_plugin = calloc(1, sizeof(struct pcm_plugin));
+    if (!sample_pcm_plugin)
+        return -ENOMEM;
+
+    priv = calloc(1, sizeof(struct sample_pcm_priv));
+    if (!priv) {
+        ret = -ENOMEM;
+        goto err_plugin_free;
+    }
+
+    sample_pcm_constrs.access = (PCM_FORMAT_BIT(SNDRV_PCM_ACCESS_RW_INTERLEAVED) |
+                              PCM_FORMAT_BIT(SNDRV_PCM_ACCESS_RW_NONINTERLEAVED));
+    sample_pcm_constrs.format = (PCM_FORMAT_BIT(SNDRV_PCM_FORMAT_S16_LE) |
+                              PCM_FORMAT_BIT(SNDRV_PCM_FORMAT_S24_LE) |
+                              PCM_FORMAT_BIT(SNDRV_PCM_FORMAT_S24_3LE) |
+                              PCM_FORMAT_BIT(SNDRV_PCM_FORMAT_S32_LE));
+
+    sample_pcm_plugin->card = card;
+    sample_pcm_plugin->mode = mode;
+    sample_pcm_plugin->constraints = &sample_pcm_constrs;
+    sample_pcm_plugin->priv = priv;
+
+    priv->session_id = session_id;
+
+    ret = sample_session_open(session_id, mode, priv);
+    if (ret) {
+        errno = -ret;
+        goto err_priv_free;
+    }
+    *plugin = sample_pcm_plugin;
+    return 0;
+
+err_priv_free:
+    free(priv);
+err_plugin_free:
+    free(sample_pcm_plugin);
+    return ret;
+}
+
+struct pcm_plugin_ops pcm_plugin_ops = {
+    .open = sample_pcm_open,
+    .close = sample_pcm_close,
+    .hw_params = sample_pcm_hw_params,
+    .sw_params = sample_pcm_sw_params,
+    .sync_ptr = sample_pcm_sync_ptr,
+    .writei_frames = sample_pcm_writei_frames,
+    .readi_frames = sample_pcm_readi_frames,
+    .ttstamp = sample_pcm_ttstamp,
+    .prepare = sample_pcm_prepare,
+    .start = sample_pcm_start,
+    .drop = sample_pcm_drop,
+    .mmap = sample_pcm_mmap,
+    .munmap = sample_pcm_munmap,
+    .poll = sample_pcm_poll,
+};