Add configfs interface, revamp stream grouping

Add additional callbacks for audio path configuring, after card has been sealed.

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

1 files changed, 229 insertions, 0 deletions

diff --git a/configfs.c b/configfs.c
new file mode 100644
index 0000000..dd7b7df
--- /dev/null
+++ b/configfs.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ALSA Virtual Soundcard
+ *
+ * configfs.c - configfs for virtual ALSA card
+ *
+ * Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
+ */
+
+#include <sound/core.h>
+#include "core_internal.h"
+
+static bool streams_sealed = false;
+
+static ssize_t cfg_avirt_stream_direction_show(struct config_item *item,
+					       char *page)
+{
+	ssize_t count;
+	struct avirt_stream *stream = avirt_stream_from_config_item(item);
+
+	count = sprintf(page, "%d\n", stream->direction);
+
+	return count;
+}
+CONFIGFS_ATTR_RO(cfg_avirt_stream_, direction);
+
+static ssize_t cfg_avirt_stream_map_show(struct config_item *item, char *page)
+{
+	struct avirt_stream *stream = avirt_stream_from_config_item(item);
+
+	return sprintf(page, "%s\n", stream->map);
+}
+
+static ssize_t cfg_avirt_stream_map_store(struct config_item *item,
+					  const char *page, size_t count)
+{
+	struct avirt_stream *stream = avirt_stream_from_config_item(item);
+
+	memcpy(stream->map, (char *)page, count);
+
+	return count;
+}
+CONFIGFS_ATTR(cfg_avirt_stream_, map);
+
+static ssize_t cfg_avirt_stream_channels_show(struct config_item *item,
+					      char *page)
+{
+	ssize_t count;
+	struct avirt_stream *stream = avirt_stream_from_config_item(item);
+
+	count = sprintf(page, "%d\n", stream->channels);
+
+	return count;
+}
+
+static ssize_t cfg_avirt_stream_channels_store(struct config_item *item,
+					       const char *page, size_t count)
+{
+	int err;
+	struct avirt_stream *stream = avirt_stream_from_config_item(item);
+	unsigned long tmp;
+	char *p = (char *)page;
+
+	err = kstrtoul(p, 10, &tmp);
+	if (err < 0)
+		return err;
+
+	if (tmp > INT_MAX)
+		return -ERANGE;
+
+	stream->channels = tmp;
+
+	pr_info("%s [ARGS] channels: %d\n", __func__, stream->channels);
+
+	return count;
+}
+CONFIGFS_ATTR(cfg_avirt_stream_, channels);
+
+static struct configfs_attribute *cfg_avirt_stream_attrs[] = {
+	&cfg_avirt_stream_attr_channels,
+	&cfg_avirt_stream_attr_map,
+	&cfg_avirt_stream_attr_direction,
+	NULL,
+};
+
+static void cfg_avirt_stream_release(struct config_item *item)
+{
+	pr_info("%s [ARGS] item->name:%s\n", __func__, item->ci_namebuf);
+	kfree(avirt_stream_from_config_item(item));
+}
+
+static struct configfs_item_operations cfg_avirt_stream_ops = {
+	.release = cfg_avirt_stream_release,
+};
+
+static struct config_item_type cfg_avirt_stream_type = {
+	.ct_item_ops = &cfg_avirt_stream_ops,
+	.ct_attrs = cfg_avirt_stream_attrs,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_item *
+cfg_avirt_stream_make_item(struct config_group *group, const char *name)
+{
+	char *split;
+	int direction;
+	struct avirt_stream *stream;
+
+	// Get prefix (playback_ or capture_)
+	split = strsep((char **)&name, "_");
+	if (!split) {
+		pr_err("Stream name: '%s' invalid!\n", split);
+		pr_err("Must begin with playback_ * or capture_ *\n");
+		return ERR_PTR(-EINVAL);
+	}
+	if (!strcmp(split, "playback")) {
+		direction = SNDRV_PCM_STREAM_PLAYBACK;
+	} else if (!strcmp(split, "capture")) {
+		direction = SNDRV_PCM_STREAM_CAPTURE;
+	} else {
+		pr_err("Stream name: '%s' invalid!\n", split);
+		pr_err("Must begin with playback_ * or capture_ *\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	// Get stream name, and create PCM for stream
+	split = strsep((char **)&name, "\n");
+	stream = __avirt_stream_create(split, direction);
+	if (IS_ERR(stream))
+		return ERR_PTR(PTR_ERR(stream));
+
+	config_item_init_type_name(&stream->item, name, &cfg_avirt_stream_type);
+
+	return &stream->item;
+}
+
+static ssize_t cfg_avirt_stream_group_sealed_show(struct config_item *item,
+						  char *page)
+{
+	return snprintf(page, PAGE_SIZE, "%d\n", streams_sealed);
+}
+
+static ssize_t cfg_avirt_stream_group_sealed_store(struct config_item *item,
+						   const char *page,
+						   size_t count)
+{
+	unsigned long tmp;
+	char *p = (char *)page;
+
+	if (streams_sealed) {
+		pr_err("AVIRT streams are already sealed!\n");
+		return -EPERM;
+	}
+
+	CHK_ERR(kstrtoul(p, 10, &tmp));
+
+	if (tmp != 1) {
+		pr_err("AVIRT streams can only be sealed, not unsealed!\n");
+		return -ERANGE;
+	}
+
+	streams_sealed = (bool)tmp;
+
+	CHK_ERR(__avirt_card_register());
+
+	return count;
+}
+CONFIGFS_ATTR(cfg_avirt_stream_group_, sealed);
+
+static struct configfs_attribute *cfg_avirt_stream_group_attrs[] = {
+	&cfg_avirt_stream_group_attr_sealed,
+	NULL,
+};
+
+static struct configfs_group_operations cfg_avirt_stream_group_ops = {
+	.make_item = cfg_avirt_stream_make_item};
+
+static struct config_item_type cfg_stream_group_type = {
+	.ct_group_ops = &cfg_avirt_stream_group_ops,
+	.ct_attrs = cfg_avirt_stream_group_attrs,
+	.ct_owner = THIS_MODULE};
+
+static struct config_item_type cfg_avirt_group_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct configfs_subsystem cfg_subsys = {
+	.su_group =
+		{
+			.cg_item =
+				{
+					.ci_namebuf = "avirt",
+					.ci_type = &cfg_avirt_group_type,
+				},
+		},
+};
+
+int __init __avirt_configfs_init(struct avirt_core *core)
+{
+	int err;
+
+	config_group_init(&cfg_subsys.su_group);
+	mutex_init(&cfg_subsys.su_mutex);
+	err = configfs_register_subsystem(&cfg_subsys);
+	if (err) {
+		pr_err("Cannot register configfs subsys!\n");
+		return err;
+	}
+	core->stream_group = configfs_register_default_group(
+		&cfg_subsys.su_group, "streams", &cfg_stream_group_type);
+	if (IS_ERR(core->stream_group)) {
+		err = PTR_ERR(core->stream_group);
+		pr_err("Cannot register configfs default group 'streams'!\n");
+		goto exit_configfs;
+	}
+
+	return 0;
+
+exit_configfs:
+	configfs_unregister_subsystem(&cfg_subsys);
+
+	return err;
+}
+
+void __exit __avirt_configfs_exit(struct avirt_core *core)
+{
+	configfs_unregister_default_group(core->stream_group);
+	configfs_unregister_subsystem(&cfg_subsys);
+}