Create avirt_stream structure in place of old config structures

Remove unnecessary extra memory allocation with the old config structures. We can store the snd_pcm pointer, which contains lots of info already.

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

8 files changed, 210 insertions, 350 deletions

diff --git a/Makefile b/Makefile
index dfdc715..af92bc5 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_AVIRT) += avirt_core.o
 avirt_core-y := core.o
-avirt_core-y += alsa.o
 avirt_core-y += alsa-pcm.o
 
 ifeq ($(CONFIG_AVIRT_BUILDLOCAL),)
diff --git a/alsa-pcm.c b/alsa-pcm.c
index ac9175b..d65809c 100644
--- a/alsa-pcm.c
+++ b/alsa-pcm.c
@@ -2,12 +2,13 @@
 /*
  * ALSA Virtual Soundcard
  *
- * alsa-pcm.c - ALSA PCM implementation
+ * alsa-pcm.c - AVIRT ALSA PCM interface
  *
  * Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
  */
 
-#include "alsa.h"
+#include "alsa-pcm.h"
+#include "utils.h"
 
 #define DO_AUDIOPATH_CB(ap, callback, substream, ...)                \
 	do {                                                         \
@@ -17,6 +18,36 @@
 		}                                                    \
 	} while (0)
 
+/**
+ * pcm_buff_complete_cb - PCM buffer complete callback
+ * @substreamid: pointer to ALSA PCM substream
+ * @return 0 on success or error code otherwise
+ *
+ * This should be called from a child Audio Path once it has finished processing
+ * the pcm buffer
+ */
+int pcm_buff_complete_cb(struct snd_pcm_substream *substream)
+{
+	// Notify ALSA middle layer of the elapsed period boundary
+	snd_pcm_period_elapsed(substream);
+
+	return 0;
+}
+
+static struct avirt_stream_group *avirt_stream_get_group(int direction)
+{
+	switch (direction) {
+	case SNDRV_PCM_STREAM_PLAYBACK:
+		return &coreinfo.playback;
+	case SNDRV_PCM_STREAM_CAPTURE:
+		return &coreinfo.capture;
+	default:
+		pr_err("[%s] Direction must be SNDRV_PCM_STREAM_XXX!",
+		       __func__);
+		return NULL;
+	}
+}
+
 /*******************************************************************************
  * ALSA PCM Callbacks
  ******************************************************************************/
@@ -31,13 +62,12 @@
  */
 static int pcm_open(struct snd_pcm_substream *substream)
 {
-	struct avirt_alsa_devconfig *config;
 	struct avirt_audiopath *audiopath;
-	struct avirt_alsa_group *group;
+	struct avirt_stream_group *group;
 	struct snd_pcm_hardware *hw;
-	unsigned int bytes_per_sample = 0, blocksize = 0;
+	unsigned int bytes_per_sample = 0, blocksize = 0, chans = 0;
 
-	char *uid = "ap_dummy"; // TD MF: Make this dynamic!
+	char *uid = "ap_fddsp"; // 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;
@@ -58,7 +88,7 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	}
 
 	// Get device group (playback/capture)
-	group = avirt_alsa_get_group(substream->stream);
+	group = avirt_stream_get_group(substream->stream);
 	CHK_NULL(group);
 
 	// Check if substream id is valid
@@ -70,13 +100,13 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	}
 
 	// Setup remaining hw properties
-	config = &group->config[substream->pcm->device];
-	hw->channels_min = config->channels;
-	hw->channels_max = config->channels;
-	hw->buffer_bytes_max = blocksize * hw->periods_max * bytes_per_sample *
-			       config->channels;
-	hw->period_bytes_min = blocksize * bytes_per_sample * config->channels;
-	hw->period_bytes_max = blocksize * bytes_per_sample * config->channels;
+	chans = group->streams[substream->pcm->device].channels;
+	hw->channels_min = chans;
+	hw->channels_max = chans;
+	hw->buffer_bytes_max =
+		blocksize * hw->periods_max * bytes_per_sample * chans;
+	hw->period_bytes_min = blocksize * bytes_per_sample * chans;
+	hw->period_bytes_max = blocksize * bytes_per_sample * chans;
 
 	// Do additional Audio Path 'open' callback
 	DO_AUDIOPATH_CB(audiopath, open, substream);
@@ -118,12 +148,12 @@ static int pcm_hw_params(struct snd_pcm_substream *substream,
 	int channels, err;
 	size_t bufsz;
 	struct avirt_audiopath *audiopath;
-	struct avirt_alsa_group *group;
+	struct avirt_stream_group *group;
 
-	group = avirt_alsa_get_group(substream->stream);
+	group = avirt_stream_get_group(substream->stream);
 	CHK_NULL(group);
 
-	channels = group->config[substream->pcm->device].channels;
+	channels = group->streams[substream->pcm->device].channels;
 
 	if ((params_channels(hw_params) > channels) ||
 	    (params_channels(hw_params) < channels)) {
@@ -252,11 +282,6 @@ static int pcm_get_time_info(
 	struct snd_pcm_audio_tstamp_config *audio_tstamp_config,
 	struct snd_pcm_audio_tstamp_report *audio_tstamp_report)
 {
-	struct avirt_alsa_group *group;
-
-	group = avirt_alsa_get_group(substream->stream);
-	CHK_NULL(group);
-
 	DO_AUDIOPATH_CB(((struct avirt_audiopath *)substream->private_data),
 			get_time_info, substream, system_ts, audio_ts,
 			audio_tstamp_config, audio_tstamp_report);
diff --git a/alsa-pcm.h b/alsa-pcm.h
new file mode 100755
index 0000000..c45e2a7
--- /dev/null
+++ b/alsa-pcm.h
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ALSA Virtual Soundcard
+ *
+ * alsa-pcm.h - AVIRT ALSA PCM interface
+ *
+ * Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
+ */
+
+#ifndef __AVIRT_ALSA_PCM_H__
+#define __AVIRT_ALSA_PCM_H__
+
+#include "core.h"
+
+extern struct avirt_coreinfo coreinfo;
+extern struct snd_pcm_ops pcm_ops;
+
+/**
+ * pcm_buff_complete_cb - PCM buffer complete callback
+ * @substream: pointer to ALSA PCM substream
+ * @return 0 on success or error code otherwise
+ *
+ * This should be called from a child Audio Path once it has finished processing
+ * the PCM buffer
+ */
+int pcm_buff_complete_cb(struct snd_pcm_substream *substream);
+
+#endif // __AVIRT_ALSA_PCM_H__
diff --git a/alsa.c b/alsa.c
deleted file mode 100755
index fdbe6b0..0000000
--- a/alsa.c
+++ /dev/null
@@ -1,175 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * ALSA Virtual Soundcard
- *
- * alsa.c - ALSA PCM driver for virtual ALSA card
- *
- * Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
- */
-
-#include <sound/core.h>
-#include <sound/initval.h>
-
-#include "alsa.h"
-
-static struct snd_card *card;
-
-/**
- * pcm_constructor - Constructs the ALSA PCM middle devices for this driver
- * @card: The snd_card struct to construct the devices for
- * @return 0 on success or error code otherwise
- */
-static int pcm_constructor(struct snd_card *card)
-{
-	struct snd_pcm *pcm;
-	int i;
-
-	// Allocate Playback PCM instances
-	for (i = 0; i < coreinfo.playback.devices; i++) {
-		CHK_ERR(snd_pcm_new(card,
-				    coreinfo.playback.config[i].devicename, i,
-				    1, 0, &pcm));
-
-		/** Register driver callbacks */
-		snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_ops);
-		snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &pcm_ops);
-
-		pcm->info_flags = 0;
-		strcpy(pcm->name, coreinfo.playback.config[i].devicename);
-	}
-
-	// Allocate Capture PCM instances
-	for (i = 0; i < coreinfo.capture.devices; i++) {
-		CHK_ERR(snd_pcm_new(card, coreinfo.capture.config[i].devicename,
-				    i, 0, 1, &pcm));
-
-		/** Register driver callbacks */
-		snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &pcm_ops);
-
-		pcm->info_flags = 0;
-		strcpy(pcm->name, coreinfo.capture.config[i].devicename);
-	}
-
-	return 0;
-}
-
-/**
- * alloc_dev_config - Allocates memory for ALSA device configuration
- * @return: 0 on success or error code otherwise
- */
-static int alloc_dev_config(struct avirt_alsa_devconfig **devconfig,
-			    struct avirt_alsa_devconfig *userconfig,
-			    unsigned int numdevices)
-{
-	if (numdevices == 0)
-		return 0;
-
-	*devconfig = kzalloc(sizeof(**devconfig) * numdevices, GFP_KERNEL);
-	if (!(*devconfig))
-		return -ENOMEM;
-
-	memcpy(*devconfig, userconfig,
-	       sizeof(struct avirt_alsa_devconfig) * numdevices);
-
-	return 0;
-}
-
-struct avirt_alsa_group *avirt_alsa_get_group(int direction)
-{
-	switch (direction) {
-	case SNDRV_PCM_STREAM_PLAYBACK:
-		return &coreinfo.playback;
-	case SNDRV_PCM_STREAM_CAPTURE:
-		return &coreinfo.capture;
-	default:
-		pr_err("[%s] Direction must be SNDRV_PCM_STREAM_XXX!",
-		       __func__);
-		return NULL;
-	}
-}
-
-/**
- * avirt_alsa_configure_pcm- Configure the PCM device
- * @config: Device configuration structure array
- * @direction: Direction of PCM (SNDRV_PCM_STREAM_XXX)
- * @numdevices: Number of devices (array length)
- * @return: 0 on success or error code otherwise
- */
-int avirt_alsa_configure_pcm(struct avirt_alsa_devconfig *config, int direction,
-			     unsigned int numdevices)
-{
-	struct avirt_alsa_group *group;
-
-	group = avirt_alsa_get_group(direction);
-	CHK_NULL(group);
-
-	CHK_ERR(alloc_dev_config(&group->config, config, numdevices));
-
-	group->devices = numdevices;
-
-	return 0;
-}
-
-/**
- * avirt_alsa_register - Registers the ALSA driver
- * @devptr: Platform driver device
- * @return: 0 on success or error code otherwise
- */
-int avirt_alsa_register(struct platform_device *devptr)
-{
-	static struct snd_device_ops device_ops;
-
-	// Create the card instance
-	CHK_ERR_V(snd_card_new(&devptr->dev, SNDRV_DEFAULT_IDX1, "avirt",
-			       THIS_MODULE, 0, &card),
-		  "Failed to create sound card");
-
-	strcpy(card->driver, "avirt-alsa-device");
-	strcpy(card->shortname, "avirt");
-	strcpy(card->longname, "A virtual sound card driver for ALSA");
-
-	// Create new sound device
-	CHK_ERR_V((snd_device_new(card, SNDRV_DEV_LOWLEVEL, &coreinfo,
-				  &device_ops)),
-		  "Failed to create sound device");
-
-	CHK_ERR((pcm_constructor(card)));
-
-	/** Register with the ALSA framework */
-	CHK_ERR_V(snd_card_register(card), "Device registration failed");
-
-	return 0;
-}
-
-/**
- * avirt_alsa_deregister - Deregisters the ALSA driver
- * @devptr: Platform driver device
- * @return: 0 on success or error code otherwise
- */
-int avirt_alsa_deregister(void)
-{
-	CHK_NULL(card);
-	snd_card_free(card);
-	CHK_NULL(coreinfo.playback.config);
-	kfree(coreinfo.playback.config);
-	CHK_NULL(coreinfo.capture.config);
-	kfree(coreinfo.capture.config);
-
-	return 0;
-}
-
-/**
- * pcm_buff_complete_cb - PCM buffer complete callback
- * @substreamid: pointer to ALSA PCM substream
- * @return 0 on success or error code otherwise
- *
- * This should be called from a child Audio Path once it has finished processing
- * the pcm buffer
- */
-int pcm_buff_complete_cb(struct snd_pcm_substream *substream)
-{
-	// Notify ALSA middle layer of the elapsed period boundary
-	snd_pcm_period_elapsed(substream);
-
-	return 0;
-}
diff --git a/alsa.h b/alsa.h
deleted file mode 100755
index c22a93c..0000000
--- a/alsa.h
+++ /dev/null
@@ -1,98 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * ALSA Virtual Soundcard
- *
- * alsa.h - Top level ALSA interface
- *
- * Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
- */
-
-#ifndef __AVIRT_ALSA_H__
-#define __AVIRT_ALSA_H__
-
-#include "core.h"
-
-#include <linux/platform_device.h>
-#include <linux/slab.h>
-#include <sound/pcm.h>
-
-#define PRINT_ERR(errno, errmsg) \
-	pr_err("[%s]:[ERRNO:%d]: %s ", __func__, errno, (errmsg));
-
-#define CHK_ERR(errno)                  \
-	do {                            \
-		if ((errno) < 0)        \
-			return (errno); \
-	} while (0)
-
-#define CHK_ERR_V(errno, errmsg, ...)                               \
-	do {                                                        \
-		if ((errno) < 0) {                                  \
-			PRINT_ERR((errno), (errmsg), ##__VA_ARGS__) \
-			return (errno);                             \
-		}                                                   \
-	} while (0)
-
-#define CHK_NULL(x)                     \
-	do {                            \
-		if (!(x))               \
-			return -EFAULT; \
-	} while (0)
-
-#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;
-extern struct snd_pcm_ops pcm_ops;
-
-/**
- * avirt_alsa_configure_pcm- Configure the PCM device
- * @config: Device configuration structure array
- * @direction: Direction of PCM (SNDRV_PCM_STREAM_XXX)
- * @numdevices: Number of devices (array length)
- * @return: 0 on success or error code otherwise
- */
-int avirt_alsa_configure_pcm(struct avirt_alsa_devconfig *config, int direction,
-			     unsigned int numdevices);
-
-/**
- * avirt_alsa_register - Registers the ALSA driver
- * @devptr: Platform driver device
- * @return: 0 on success or error code otherwise
- */
-int avirt_alsa_register(struct platform_device *devptr);
-
-/**
- * avirt_alsa_deregister - Deregisters the ALSA driver
- * @devptr: Platform driver device
- * @return: 0 on success or error code otherwise
- */
-int avirt_alsa_deregister(void);
-
-/**
- * avirt_alsa_get_group - Gets the device group for the specified direction
- * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
- * @return: Either the playback or capture device group on success,
- * or NULL otherwise
- */
-struct avirt_alsa_group *avirt_alsa_get_group(int direction);
-
-/**
- * pcm_buff_complete_cb - PCM buffer complete callback
- * @substream: pointer to ALSA PCM substream
- * @return 0 on success or error code otherwise
- *
- * This should be called from a child Audio Path once it has finished processing
- * the PCM buffer
- */
-int pcm_buff_complete_cb(struct snd_pcm_substream *substream);
-
-#endif // __AVIRT_ALSA_H__
diff --git a/core.c b/core.c
index 360f174..c9e8d25 100644
--- a/core.c
+++ b/core.c
@@ -9,9 +9,13 @@
 
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/string.h>
+#include <sound/core.h>
+#include <sound/initval.h>
 
 #include "avirt/core.h"
-#include "alsa.h"
+#include "alsa-pcm.h"
+#include "utils.h"
 
 MODULE_AUTHOR("JOSHANNE <james.oshannessy@fiberdyne.com.au>");
 MODULE_AUTHOR("MFARRUGI <mark.farrugia@fiberdyne.com.au>");
@@ -58,8 +62,8 @@ module_param_array(capture_chans, int, NULL, DEFAULT_FILE_PERMS);
 MODULE_PARM_DESC(capture_chans, "Channels per capture device");
 
 static struct avirt_core {
+	struct snd_card *card;
 	struct device *dev;
-
 	struct class *avirt_class;
 	struct platform_device *platform_dev;
 } core;
@@ -78,8 +82,8 @@ static LIST_HEAD(audiopath_list);
  */
 static int avirt_probe(struct platform_device *devptr)
 {
-	// struct avirt_alsa_devconfig capture_config[MAX_PCM_DEVS];
-	struct avirt_alsa_devconfig playback_config[MAX_PCM_DEVS];
+	static struct snd_device_ops device_ops;
+	struct snd_pcm **pcm;
 	int err = 0, i = 0;
 
 	if (playback_num == 0 && capture_num == 0) {
@@ -87,51 +91,71 @@ static int avirt_probe(struct platform_device *devptr)
 		return -EINVAL;
 	}
 
-	// Set up playback
-	for (i = 0; i < playback_num; i++) {
-		if (!playback_names[i]) {
-			pr_err("Playback config dev name is NULL for idx=%d\n",
-			       i);
-			return -EINVAL;
-		}
-		memcpy((char *)playback_config[i].devicename, playback_names[i],
-		       MAX_NAME_LEN);
-		if (playback_chans[i] == 0) {
-			pr_err("Playback config channels is 0 for idx=%d\n", i);
-			return -EINVAL;
+	// Create the card instance
+	CHK_ERR_V(snd_card_new(&devptr->dev, SNDRV_DEFAULT_IDX1, "avirt",
+			       THIS_MODULE, 0, &core.card),
+		  "Failed to create sound card");
+
+	strcpy(core.card->driver, "avirt-alsa-device");
+	strcpy(core.card->shortname, "avirt");
+	strcpy(core.card->longname, "A virtual sound card driver for ALSA");
+
+	// Create new sound device
+	CHK_ERR_V((snd_device_new(core.card, SNDRV_DEV_LOWLEVEL, &coreinfo,
+				  &device_ops)),
+		  "Failed to create sound device");
+
+	// TEMP
+	if (playback_num > 0) {
+		coreinfo.playback.devices = playback_num;
+		coreinfo.playback.streams = kzalloc(
+			sizeof(*coreinfo.playback.streams) * playback_num,
+			GFP_KERNEL);
+		for (i = 0; i < playback_num; i++) {
+			pcm = &coreinfo.playback.streams[i].pcm;
+			CHK_ERR(snd_pcm_new(core.card, playback_names[i], i, 1,
+					    0, pcm));
+
+			/** Register driver callbacks */
+			snd_pcm_set_ops(*pcm, SNDRV_PCM_STREAM_PLAYBACK,
+					&pcm_ops);
+
+			(*pcm)->info_flags = 0;
+			strcpy((*pcm)->name, playback_names[i]);
+			coreinfo.playback.streams[i].channels =
+				playback_chans[i];
+			pr_info("snd_pcm_new: name: %s, chans: %d\n",
+				(*pcm)->name,
+				coreinfo.playback.streams[i].channels);
 		}
-		playback_config[i].channels = playback_chans[i];
 	}
-	err = avirt_alsa_configure_pcm(playback_config,
-				       SNDRV_PCM_STREAM_PLAYBACK, playback_num);
-	if (err < 0)
-		return err;
-
-// Does not work yet!
-#if 0
-	// Set up capture
-	for (i = 0; i < capture_num; i++) {
-		if (!capture_names[i]) {
-			pr_err("Capture config devicename is NULL for idx=%d",
-			       i);
-			return -EINVAL;
-		}
-		memcpy((char *)capture_config[i].devicename, capture_names[i],
-		       255);
 
-		if (capture_chans[i] == 0) {
-			pr_err("Capture config channels is 0 for idx=%d");
-			return -EINVAL;
+	if (capture_num > 0) {
+		coreinfo.capture.devices = capture_num;
+		coreinfo.capture.streams =
+			kzalloc(sizeof(*coreinfo.capture.streams) * capture_num,
+				GFP_KERNEL);
+		for (i = 0; i < capture_num; i++) {
+			pcm = &coreinfo.capture.streams[i].pcm;
+			CHK_ERR(snd_pcm_new(core.card, capture_names[i],
+					    i + playback_num, 0, 1, pcm));
+
+			/** Register driver callbacks */
+			snd_pcm_set_ops(*pcm, SNDRV_PCM_STREAM_CAPTURE,
+					&pcm_ops);
+
+			(*pcm)->info_flags = 0;
+			strcpy((*pcm)->name, capture_names[i]);
+			coreinfo.capture.streams[i].channels = capture_chans[i];
+			pr_info("snd_pcm_new: name: %s, chans: %d\n",
+				(*pcm)->name,
+				coreinfo.capture.streams[i].channels);
 		}
-		capture_config[i].channels = capture_chans[i];
 	}
-	err = avirt_alsa_configure_pcm(capture_config, SNDRV_PCM_STREAM_CAPTURE, capture_num);
-	if (err < 0)
-		return err;
-#endif
+	// TEMP
 
-	// Register for ALSA
-	CHK_ERR(avirt_alsa_register(devptr));
+	/** Register with the ALSA framework */
+	CHK_ERR_V(snd_card_register(core.card), "Device registration failed");
 
 	return err;
 }
@@ -143,7 +167,13 @@ static int avirt_probe(struct platform_device *devptr)
  */
 static int avirt_remove(struct platform_device *devptr)
 {
-	return avirt_alsa_deregister();
+	snd_card_free(core.card);
+	CHK_NULL(coreinfo.playback.streams);
+	kfree(coreinfo.playback.streams);
+	CHK_NULL(coreinfo.capture.streams);
+	kfree(coreinfo.capture.streams);
+
+	return 0;
 }
 
 static struct platform_driver avirt_driver = {
diff --git a/core.h b/core.h
index 98d1bbd..4a0157a 100644
--- a/core.h
+++ b/core.h
@@ -11,6 +11,7 @@
 #define __AVIRT_CORE_H__
 
 #include <sound/pcm.h>
+#include <linux/configfs.h>
 
 #define MAX_NAME_LEN 32
 
@@ -37,19 +38,20 @@ struct avirt_audiopath {
 };
 
 /*
- * ALSA Substream device configuration
+ * Audio stream configuration
  */
-struct avirt_alsa_devconfig {
-	const char devicename[MAX_NAME_LEN];
-	int channels;
+struct avirt_stream {
+	struct snd_pcm *pcm; /* Stream PCM device */
+	unsigned int channels; /* Stream channel count */
+	struct config_item item; /* configfs item reference */
 };
 
 /**
- * Collection of ALSA devices
+ * Collection of audio streams
  */
-struct avirt_alsa_group {
-	struct avirt_alsa_devconfig *config;
-	int devices;
+struct avirt_stream_group {
+	struct avirt_stream *streams; /* AVIRT stream array */
+	unsigned int devices; /* Number of stream devices */
 };
 
 /**
@@ -58,8 +60,8 @@ struct avirt_alsa_group {
 struct avirt_coreinfo {
 	unsigned int version[3];
 
-	struct avirt_alsa_group playback;
-	struct avirt_alsa_group capture;
+	struct avirt_stream_group playback;
+	struct avirt_stream_group capture;
 
 	avirt_buff_complete pcm_buff_complete;
 };
diff --git a/utils.h b/utils.h
new file mode 100644
index 0000000..b449938
--- /dev/null
+++ b/utils.h
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ALSA Virtual Soundcard
+ *
+ * utils.h - Some useful utilities for AVIRT
+ *
+ * Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
+ */
+
+#ifndef __AVIRT_UTILS_H__
+#define __AVIRT_UTILS_H__
+
+#include <linux/slab.h>
+
+#define PRINT_ERR(errno, errmsg) \
+	pr_err("[%s]:[ERRNO:%d]: %s ", __func__, errno, (errmsg));
+
+#define CHK_ERR(errno)                  \
+	do {                            \
+		if ((errno) < 0)        \
+			return (errno); \
+	} while (0)
+
+#define CHK_ERR_V(errno, errmsg, ...)                               \
+	do {                                                        \
+		if ((errno) < 0) {                                  \
+			PRINT_ERR((errno), (errmsg), ##__VA_ARGS__) \
+			return (errno);                             \
+		}                                                   \
+	} while (0)
+
+#define CHK_NULL(x)                     \
+	do {                            \
+		if (!(x))               \
+			return -EFAULT; \
+	} while (0)
+
+#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)
+
+#endif