Add support for managing mixer knobs to snd interface

kernel/include/mod/snd.h

@@ -4,14 +4,29 @@
 /* The format isn't really used for anything right now */
 #define SND_FORMAT_L16SLE 0  /* Linear 16-bit signed little endian */
 
+#include <lib/snd.h>
 #include <logging.h>
 #include <system.h>
 
+#define SND_KNOB_VENDOR 1024
+
+typedef uint16_t snd_mixer_enum_t;
+
+typedef struct snd_knob {
+	char name[SND_KNOB_NAME_SIZE];
+	uint32_t id;
+} snd_knob_t;
+
 typedef struct snd_device {
 	char name[256];            /* Name of the device. */
 	void * device;             /* Private data for the device. May be NULL. */
 	uint32_t playback_speed;   /* Playback speed in Hz */
 	uint32_t playback_format;  /* Playback format (SND_FORMAT_*) */
+
+	snd_knob_t *knobs;
+	uint32_t num_knobs;
+	int (*mixer_read)(uint32_t knob_id, uint32_t *val);
+	int (*mixer_write)(uint32_t knob_id, uint32_t val);
 } snd_device_t;
 
 /*

modules/snd.c

@@ -14,6 +14,7 @@
 #include <mod/snd.h>
 
 #include <list.h>
+#include <mod/shell.h>
 #include <module.h>
 #include <ringbuffer.h>
 #include <system.h>
@@ -140,8 +141,41 @@ int snd_request_buf(snd_device_t * device, uint32_t size, uint8_t *buffer) {
 	return size;
 }
 
+static snd_device_t * snd_main_device() {
+	spin_lock(&_devices_lock);
+	foreach(node, &_devices) {
+		spin_unlock(&_devices_lock);
+		return node->value;
+	}
+
+	spin_unlock(&_devices_lock);
+	return NULL;
+}
+
+DEFINE_SHELL_FUNCTION(snd_full, "[debug] turn snd master to full") {
+	snd_main_device()->mixer_write(SND_KNOB_MASTER, UINT32_MAX);
+
+	return 0;
+}
+
+DEFINE_SHELL_FUNCTION(snd_half, "[debug] turn snd master to half") {
+	snd_main_device()->mixer_write(SND_KNOB_MASTER, UINT32_MAX / 2);
+
+	return 0;
+}
+
+DEFINE_SHELL_FUNCTION(snd_off, "[debug] turn snd master to lowest volume") {
+	snd_main_device()->mixer_write(SND_KNOB_MASTER, 0);
+
+	return 0;
+}
+
 static int init(void) {
 	vfs_mount("/dev/dsp", &_main_fnode);
+
+	BIND_SHELL_FUNCTION(snd_full);
+	BIND_SHELL_FUNCTION(snd_half);
+	BIND_SHELL_FUNCTION(snd_off);
 	return 0;
 }
 

userspace/lib/snd.h

@@ -0,0 +1,37 @@
+#ifndef USERSPACE_LIB_SND_H
+#define USERSPACE_LIB_SND_H
+
+#include <types.h>
+
+#define SND_MAX_KNOBS 256
+#define SND_KNOB_NAME_SIZE 256
+
+#define SND_KNOB_MASTER 0
+#define SND_DEVICE_MAIN 0
+
+typedef struct snd_knob_list {
+	uint32_t device;
+	uint32_t num;
+	uint32_t ids[SND_MAX_KNOBS];
+} snd_knob_list_t;
+
+typedef struct snd_knob_info {
+	uint32_t device;
+	uint32_t id;
+	char name[SND_KNOB_NAME_SIZE];
+} snd_knob_info_t;
+
+typedef struct snd_knob_value {
+	uint32_t device;
+	uint32_t id;
+	uint32_t val;
+} snd_knob_value_t;
+
+
+/* IOCTLs */
+#define SND_MIXER_GET_KNOBS 0
+#define SND_MIXER_GET_KNOB_INFO  1
+#define SND_MIXER_READ_KNOB 2
+#define SND_MIXER_WRITE_KNOB 3
+
+#endif  /* USERSPACE_LIB_SND_H */