selftests: alsa - add PCM test

This initial code does a simple sample transfer tests. By default,
all PCM devices are detected and tested with short and long
buffering parameters for 4 seconds. If the sample transfer timing
is not in a +-100ms boundary, the test fails. Only the interleaved
buffering scheme is supported in this version.

The configuration may be modified with the configuration files.
A specific hardware configuration is detected and activated
using the sysfs regex matching. This allows to use the DMI string
(/sys/class/dmi/id/* tree) or any other system parameters
exposed in sysfs for the matching for the CI automation.

The configuration file may also specify the PCM device list to detect
the missing PCM devices.

v1..v2:
  - added missing alsa-local.h header file

Cc: Mark Brown <[email protected]>
Cc: Pierre-Louis Bossart <[email protected]>
Cc: Liam Girdwood <[email protected]>
Cc: Jesse Barnes <[email protected]>
Cc: Jimmy Cheng-Yi Chiang <[email protected]>
Cc: Curtis Malainey <[email protected]>
Cc: Brian Norris <[email protected]>
Signed-off-by: Jaroslav Kysela <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>

Author: perexg

tools/testing/selftests/alsa/Makefile

@@ -7,6 +7,8 @@ ifeq ($(LDLIBS),)
 LDLIBS += -lasound
 endif
 
-TEST_GEN_PROGS := mixer-test
+TEST_GEN_PROGS := mixer-test pcm-test
+
+pcm-test: pcm-test.c conf.c
 
 include ../lib.mk

tools/testing/selftests/alsa/alsa-local.h

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// kselftest configuration helpers for the hw specific configuration
+//
+// Original author: Jaroslav Kysela <[email protected]>
+// Copyright (c) 2022 Red Hat Inc.
+
+#ifndef __ALSA_LOCAL_H
+#define __ALSA_LOCAL_H
+
+#include <alsa/asoundlib.h>
+
+void conf_load(void);
+void conf_free(void);
+snd_config_t *conf_by_card(int card);
+snd_config_t *conf_get_subtree(snd_config_t *root, const char *key1, const char *key2);
+int conf_get_count(snd_config_t *root, const char *key1, const char *key2);
+const char *conf_get_string(snd_config_t *root, const char *key1, const char *key2, const char *def);
+long conf_get_long(snd_config_t *root, const char *key1, const char *key2, long def);
+int conf_get_bool(snd_config_t *root, const char *key1, const char *key2, int def);
+
+#endif /* __ALSA_LOCAL_H */