Add 'uid' field to AP, store AP in PCM private data, fix helper macros

We want to use a UID when registering APs, that must start with "ap_", and acts as a unique identifier for each AP.
To move forward with the adoption of routing PCMs to differing APs, we now store the AP in the PCM private data - set at pcm_open.
A fix to the helper macros now allows additional args to be passed in for inclusion to the debug string

Signed-off-by: Mark Farrugia <mark.farrugia@fiberdyne.com.au>

6 files changed, 79 insertions, 56 deletions

diff --git a/alsa-pcm.c b/alsa-pcm.c
index 9b55a14..ac9175b 100644
--- a/alsa-pcm.c
+++ b/alsa-pcm.c
@@ -9,13 +9,8 @@
 
 #include "alsa.h"
 
-#define AP_LOGNAME "CORE"
-
-#define DO_AUDIOPATH_CB(callback, substream, ...)                    \
+#define DO_AUDIOPATH_CB(ap, callback, substream, ...)                \
 	do {                                                         \
-		struct avirt_audiopath *ap;                          \
-		ap = avirt_get_current_audiopath();                  \
-		CHK_NULL_V(ap, "Cannot find Audio Path!");           \
 		if (ap->pcm_ops->callback) {                         \
 			return ap->pcm_ops->callback((substream),    \
 						     ##__VA_ARGS__); \
@@ -42,8 +37,10 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	struct snd_pcm_hardware *hw;
 	unsigned int bytes_per_sample = 0, blocksize = 0;
 
-	audiopath = avirt_get_current_audiopath();
-	CHK_NULL_V(audiopath, "Cannot find Audio Path!");
+	char *uid = "ap_dummy"; // TD MF: Make this dynamic!
+	audiopath = avirt_get_audiopath(uid);
+	CHK_NULL_V(audiopath, "Cannot find Audio Path uid: '%s'!", uid);
+	substream->private_data = audiopath;
 
 	blocksize = audiopath->blocksize;
 
@@ -82,7 +79,7 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	hw->period_bytes_max = blocksize * bytes_per_sample * config->channels;
 
 	// Do additional Audio Path 'open' callback
-	DO_AUDIOPATH_CB(open, substream);
+	DO_AUDIOPATH_CB(audiopath, open, substream);
 
 	return 0;
 }
@@ -99,7 +96,8 @@ static int pcm_close(struct snd_pcm_substream *substream)
 {
 	DINFO(AP_LOGNAME, "");
 	// Do additional Audio Path 'close' callback
-	DO_AUDIOPATH_CB(close, substream);
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			close, substream);
 
 	return 0;
 }
@@ -133,9 +131,7 @@ static int pcm_hw_params(struct snd_pcm_substream *substream,
 		return -EINVAL;
 	}
 
-	audiopath = avirt_get_current_audiopath();
-	CHK_NULL_V(audiopath, "Cannot find Audio Path!");
-
+	audiopath = ((struct avirt_audiopath *)substream->private_data);
 	bufsz = params_buffer_bytes(hw_params) * audiopath->hw->periods_max;
 
 	err = snd_pcm_lib_alloc_vmalloc_buffer(substream, bufsz);
@@ -183,7 +179,8 @@ static int pcm_hw_free(struct snd_pcm_substream *substream)
 static int pcm_prepare(struct snd_pcm_substream *substream)
 {
 	// Do additional Audio Path 'prepare' callback
-	DO_AUDIOPATH_CB(prepare, substream);
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			prepare, substream);
 
 	return 0;
 }
@@ -212,7 +209,8 @@ static int pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 	}
 
 	// Do additional Audio Path 'trigger' callback
-	DO_AUDIOPATH_CB(trigger, substream, cmd);
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			trigger, substream, cmd);
 
 	return 0;
 }
@@ -230,7 +228,8 @@ static int pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 static snd_pcm_uframes_t pcm_pointer(struct snd_pcm_substream *substream)
 {
 	// Do additional Audio Path 'pointer' callback
-	DO_AUDIOPATH_CB(pointer, substream);
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			pointer, substream);
 
 	return 0;
 }
@@ -258,7 +257,8 @@ static int pcm_get_time_info(
 	group = avirt_alsa_get_group(substream->stream);
 	CHK_NULL(group);
 
-	DO_AUDIOPATH_CB(get_time_info, substream, system_ts, audio_ts,
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			get_time_info, substream, system_ts, audio_ts,
 			audio_tstamp_config, audio_tstamp_report);
 
 	return 0;
@@ -288,8 +288,8 @@ static int pcm_copy_user(struct snd_pcm_substream *substream, int channel,
 	//offset = frames_to_bytes(runtime, pos);
 
 	// Do additional Audio Path 'copy_user' callback
-	DINFO(AP_LOGNAME, "");
-	DO_AUDIOPATH_CB(copy_user, substream, channel, pos, src, count);
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			copy_user, substream, channel, pos, src, count);
 
 	return 0;
 }
@@ -310,8 +310,9 @@ static int pcm_copy_user(struct snd_pcm_substream *substream, int channel,
 static int pcm_copy_kernel(struct snd_pcm_substream *substream, int channel,
 			   unsigned long pos, void *buf, unsigned long count)
 {
-	DINFO(AP_LOGNAME, "");
-	DO_AUDIOPATH_CB(copy_kernel, substream, channel, pos, buf, count);
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			copy_kernel, substream, channel, pos, buf, count);
+
 	return 0;
 }
 
@@ -326,16 +327,18 @@ static int pcm_copy_kernel(struct snd_pcm_substream *substream, int channel,
  */
 int pcm_ack(struct snd_pcm_substream *substream)
 {
-	DINFO(AP_LOGNAME, "");
-	DO_AUDIOPATH_CB(ack, substream);
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			ack, substream);
+
 	return 0;
 }
 
 static int pcm_silence(struct snd_pcm_substream *substream, int channel,
 		       snd_pcm_uframes_t pos, snd_pcm_uframes_t count)
 {
-	DINFO(AP_LOGNAME, "");
-	DO_AUDIOPATH_CB(fill_silence, substream, channel, pos, count);
+	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
+			fill_silence, substream, channel, pos, count);
+
 	return 0;
 }
 
diff --git a/alsa.c b/alsa.c
index a899bb1..fdbe6b0 100755
--- a/alsa.c
+++ b/alsa.c
@@ -7,7 +7,6 @@
  * Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
  */
 
-#include <linux/slab.h>
 #include <sound/core.h>
 #include <sound/initval.h>
 
diff --git a/alsa.h b/alsa.h
index 12148b9..c22a93c 100755
--- a/alsa.h
+++ b/alsa.h
@@ -13,10 +13,11 @@
 #include "core.h"
 
 #include <linux/platform_device.h>
+#include <linux/slab.h>
 #include <sound/pcm.h>
 
-#define PRINT_ERR(errno, errmsg, ...) \
-	pr_err("[%s()] %s [ERRNO:%d]", __func__, errmsg, ##__VA_ARGS__, errno);
+#define PRINT_ERR(errno, errmsg) \
+	pr_err("[%s]:[ERRNO:%d]: %s ", __func__, errno, (errmsg));
 
 #define CHK_ERR(errno)                  \
 	do {                            \
@@ -38,12 +39,15 @@
 			return -EFAULT; \
 	} while (0)
 
-#define CHK_NULL_V(x, errmsg, ...)                                 \
-	do {                                                       \
-		if (!(x)) {                                        \
-			PRINT_ERR(EFAULT, (errmsg), ##__VA_ARGS__) \
-			return -EFAULT;                            \
-		}                                                  \
+#define CHK_NULL_V(x, errmsg, ...)                                            \
+	do {                                                                  \
+		if (!(x)) {                                                   \
+			char *errmsg_done =                                   \
+				kasprintf(GFP_KERNEL, errmsg, ##__VA_ARGS__); \
+			PRINT_ERR(EFAULT, errmsg_done);                       \
+			kfree(errmsg_done);                                   \
+			return -EFAULT;                                       \
+		}                                                             \
 	} while (0)
 
 extern struct avirt_coreinfo coreinfo;
diff --git a/core.c b/core.c
index e77dfb9..360f174 100644
--- a/core.c
+++ b/core.c
@@ -8,7 +8,6 @@
  */
 
 #include <linux/module.h>
-#include <linux/slab.h>
 #include <linux/platform_device.h>
 
 #include "avirt/core.h"
@@ -279,13 +278,13 @@ static struct kobj_type avirt_audiopath_ktype = {
 
 /**
  * create_avirt_audiopath_obj - creates an Audio Path object
- * @name: name of the Audio Path
+ * @uid: Unique ID of the Audio Path
  *
  * This creates an Audio Path object and assigns the kset and registers
  * it with sysfs.
  * @return: Pointer to the Audio Path object or NULL if it failed.
  */
-static struct avirt_audiopath_obj *create_avirt_audiopath_obj(const char *name)
+static struct avirt_audiopath_obj *create_avirt_audiopath_obj(const char *uid)
 {
 	struct avirt_audiopath_obj *avirt_audiopath;
 	int retval;
@@ -295,7 +294,7 @@ static struct avirt_audiopath_obj *create_avirt_audiopath_obj(const char *name)
 		return NULL;
 	avirt_audiopath->kobj.kset = avirt_audiopath_kset;
 	retval = kobject_init_and_add(&avirt_audiopath->kobj,
-				      &avirt_audiopath_ktype, kobj, "%s", name);
+				      &avirt_audiopath_ktype, kobj, "%s", uid);
 	if (retval) {
 		kobject_put(&avirt_audiopath->kobj);
 		return NULL;
@@ -314,14 +313,20 @@ static void destroy_avirt_audiopath_obj(struct avirt_audiopath_obj *p)
 }
 
 /**
- * avirt_get_current_audiopath - retrieves the current Audio Path
- * @return: Current Audio Path
+ * avirt_get_audiopath - retrieves the Audio Path by its UID
+ * @uid: Unique ID for the Audio Path
+ * @return: Corresponding Audio Path
  */
-struct avirt_audiopath *avirt_get_current_audiopath(void)
+struct avirt_audiopath *avirt_get_audiopath(const char *uid)
 {
-	struct avirt_audiopath_obj *ap_obj = list_entry(
-		audiopath_list.next, struct avirt_audiopath_obj, list);
-	return ap_obj->path;
+	struct avirt_audiopath_obj *ap_obj;
+	list_for_each_entry (ap_obj, &audiopath_list, list) {
+		pr_info("get_ap %s\n", ap_obj->path->uid);
+		if (!strcmp(ap_obj->path->uid, uid))
+			return ap_obj->path;
+	}
+
+	return NULL;
 }
 
 /**
@@ -340,7 +345,7 @@ int avirt_register_audiopath(struct avirt_audiopath *audiopath,
 		return -EINVAL;
 	}
 
-	audiopath_obj = create_avirt_audiopath_obj(audiopath->name);
+	audiopath_obj = create_avirt_audiopath_obj(audiopath->uid);
 	if (!audiopath_obj) {
 		pr_info("failed to alloc driver object\n");
 		return -ENOMEM;
@@ -348,8 +353,8 @@ int avirt_register_audiopath(struct avirt_audiopath *audiopath,
 	audiopath_obj->path = audiopath;
 
 	audiopath->context = audiopath_obj;
-	D_INFOK("Registered new Audio Path: %s", audiopath->name);
-	D_INFOK("\tBlocksize: %d, Periods: %d", audiopath->blocksize,
+	pr_info("Registered new Audio Path: %s\n", audiopath->uid);
+	pr_info("\tBlocksize: %d, Periods: %d\n", audiopath->blocksize,
 		audiopath->hw->periods_max);
 	list_add_tail(&audiopath_obj->list, &audiopath_list);
 
@@ -382,7 +387,7 @@ int avirt_deregister_audiopath(struct avirt_audiopath *audiopath)
 
 	list_del(&audiopath_obj->list);
 	destroy_avirt_audiopath_obj(audiopath_obj);
-	pr_info("Deregistered Audio Path %s\n", audiopath->name);
+	pr_info("Deregistered Audio Path %s\n", audiopath->uid);
 
 	return 0;
 }
diff --git a/core.h b/core.h
index fb64030..98d1bbd 100644
--- a/core.h
+++ b/core.h
@@ -26,11 +26,12 @@ typedef int (*avirt_buff_complete)(struct snd_pcm_substream *substream);
  * AVIRT Audio Path info
  */
 struct avirt_audiopath {
-	const char *name;
-	unsigned int version[3];
-	struct snd_pcm_hardware *hw;
-	struct snd_pcm_ops *pcm_ops;
-	unsigned int blocksize;
+	const char *uid; /* Unique identifier */
+	const char *name; /* Pretty name */
+	unsigned int version[3]; /* Version - Major.Minor.Ext */
+	struct snd_pcm_hardware *hw; /* ALSA PCM HW conf */
+	struct snd_pcm_ops *pcm_ops; /* ALSA PCM op table */
+	unsigned int blocksize; /* Audio frame size accepted */
 
 	void *context;
 };
@@ -80,9 +81,19 @@ int avirt_register_audiopath(struct avirt_audiopath *audiopath,
 int avirt_deregister_audiopath(struct avirt_audiopath *audiopath);
 
 /**
- * avirt_get_current_audiopath - retrieves the current Audio Path
- * @return: Current Audio Path
+ * avirt_get_audiopath - retrieves the Audio Path by it's UID
+ * @uid: Unique ID for the Audio Path
+ * @return: Corresponding Audio Path
+ */
+struct avirt_audiopath *avirt_get_audiopath(const char *uid);
+
+/**
+ * avirt_subscribe_stream - subscribe the Audio Path to the given streams
+ * @audiopath: Audio Path to subscribe for
+ * @streams: The streams to subscribe the Audio Path to
+ * return: 0 on success or error code otherwise
  */
-struct avirt_audiopath *avirt_get_current_audiopath(void);
+int avirt_subscribe_stream(struct avirt_audiopath *audiopath,
+			   const char **streams);
 
 #endif // __AVIRT_CORE_H__
diff --git a/dummy/dummy.c b/dummy/dummy.c
index 54d4dcc..fa9dd41 100644
--- a/dummy/dummy.c
+++ b/dummy/dummy.c
@@ -244,6 +244,7 @@ static struct snd_pcm_hardware dummyap_hw = {
 };
 
 static struct avirt_audiopath dummyap_module = {
+	.uid = "ap_dummy",
 	.name = "Dummy Audio Path",
 	.version = { 0, 0, 1 },
 	.hw = &dummyap_hw,