tinyalsa: add support for mixer plugins

Update the mixer framework to support plugins. Add ability for physical
card to have either kernel registered mixer controls or plugin
registered mixer control or both. Split mixer controls into two groups,
one for kernel registered (hw_grp) and the other for plugin registered
(virtual_grp).

Signed-off-by: Rohit kumar <rohitkr@codeaurora.org>
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>

1 files changed, 112 insertions, 0 deletions

diff --git a/src/mixer_hw.c b/src/mixer_hw.c
new file mode 100644
index 0000000..2e86dfa
--- /dev/null
+++ b/src/mixer_hw.c
@@ -0,0 +1,112 @@
+/* mixer_hw.c
+** Copyright (c) 2019, The Linux Foundation.
+**
+** 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 <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <ctype.h>
+#include <poll.h>
+
+#include <sys/ioctl.h>
+
+#include <linux/ioctl.h>
+#include <sound/asound.h>
+
+#include "mixer_io.h"
+
+/** Store the hardware (kernel interface) mixer data */
+struct mixer_hw_data {
+    /* Card number for the mixer */
+    unsigned int card;
+    /* File descriptor of the mixer device node */
+    int fd;
+};
+
+static void mixer_hw_close(void *data)
+{
+    struct mixer_hw_data *hw_data = data;
+
+    if (!hw_data)
+        return;
+
+    if (hw_data->fd >= 0)
+        close(hw_data->fd);
+
+    hw_data->fd = -1;
+    free(hw_data);
+    hw_data = NULL;
+}
+
+static int mixer_hw_ioctl(void *data, unsigned int cmd, ...)
+{
+    struct mixer_hw_data *hw_data = data;
+    va_list ap;
+    void *arg;
+
+    va_start(ap, cmd);
+    arg = va_arg(ap, void *);
+    va_end(ap);
+
+    return ioctl(hw_data->fd, cmd, arg);
+}
+
+static const struct mixer_ops mixer_hw_ops = {
+    .close = mixer_hw_close,
+    .ioctl = mixer_hw_ioctl,
+};
+
+int mixer_hw_open(unsigned int card, void **data,
+                  const struct mixer_ops **ops)
+{
+    struct mixer_hw_data *hw_data;
+    int fd;
+    char fn[256];
+
+    snprintf(fn, sizeof(fn), "/dev/snd/controlC%u", card);
+    fd = open(fn, O_RDWR);
+    if (fd < 0)
+        return fd;
+
+    hw_data = calloc(1, sizeof(*hw_data));
+    if (!hw_data)
+        return -1;
+
+    hw_data->card = card;
+    hw_data->fd = fd;
+    *data = hw_data;
+    *ops = &mixer_hw_ops;
+
+    return fd;
+}