[PATCH 7/7] sound/usb: Update ALSA driver to use Managed Media Controller API

[Shuah Khan <shuahkh@osg.samsung.com>]

Change ALSA driver to use Managed ~media Managed Controller
API to share tuner with DVB and V4L2 drivers that control
AU0828 media device.  Media device is created based on a
newly added field value in the struct snd_usb_audio_quirk.
Using this approach, the media controller API usage can be
added for a specific device. In this patch, Media Controller
API is enabled for AU0828 hw. snd_usb_create_quirk() will
check this new field, if set will create a media device using
media_device_get_devres() interface.

media_device_get_devres() will allocate a new media device
devres or return an existing one, if it finds one.

During probe, media usb driver could have created the media
device devres. It will then register the media device if it
isn't already registered. Media device unregister is done from
usb_audio_disconnect().

During probe, media usb driver could have created the
media device devres. It will then register the media
device if it isn't already registered. Media device
unregister is done from usb_audio_disconnect().

New structure media_ctl is added to group the new
fields to support media entity and links. This new
structure is added to struct snd_usb_substream.

A new entity_notify hook and a new ALSA capture media
entity are registered from snd_usb_pcm_open() after
setting up hardware information for the PCM device.

When a new entity is registered, Media Controller API
interface media_device_register_entity() invokes all
registered entity_notify hooks for the media device.
ALSA entity_notify hook parses all the entity list to
find a link from decoder it ALSA entity. This indicates
that the bridge driver created a link from decoder to
ALSA capture entity. At this time, ALSA will attempt to
enable the tuner to link the tuner to the decoder calling
media_entity_setup_link(). media_entity_setup_link() will
either return success activating tuner to decoder link or
error if it tuner is busy.

Media pipeline gets started to mark the tuner busy from
snd_usb_substream_capture_trigger() in response to
SNDRV_PCM_TRIGGER_START and pipeline is stopped in
response to SNDRV_PCM_TRIGGER_STOP. snd_usb_pcm_close()
stops pipeline to cover the case when SNDRV_PCM_TRIGGER_STOP
isn't issued. Pipeline start and stop are done only when
decoder_linked is set. Tuner enable step could be done
from snd_usb_substream_capture_trigger(). The reason it
is done from snd_usb_pcm_open() is that it reduces the
work that is needed from snd_usb_substream_capture_trigger().

There is an open issue with graph_mutex hold in Media Controller
media_entity_pipeline_start() and media_entity_pipeline_stop()
API. snd-us-audio calls these from snd_usb_substream_capture_trigger()
which could be called in irq path. This issue needs to be resolved
before this patch can go in.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
 sound/usb/Makefile       |  15 ++-
 sound/usb/card.c         |   5 +
 sound/usb/card.h         |   1 +
 sound/usb/media.c        | 260 +++++++++++++++++++++++++++++++++++++++++++++++
 sound/usb/media.h        |  52 ++++++++++
 sound/usb/pcm.c          |  15 ++-
 sound/usb/quirks-table.h |   1 +
 sound/usb/quirks.c       |   9 +-
 sound/usb/stream.c       |   2 +
 sound/usb/usbaudio.h     |   1 +
 10 files changed, 357 insertions(+), 4 deletions(-)
 create mode 100644 sound/usb/media.c
 create mode 100644 sound/usb/media.h

diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index 2d2d122..665fdd9 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile
@@ -2,6 +2,18 @@
 # Makefile for ALSA
 #
 
+# Media Controller
+ifeq ($(CONFIG_MEDIA_CONTROLLER),y)
+  ifeq ($(CONFIG_MEDIA_SUPPORT),y)
+        KBUILD_CFLAGS += -DUSE_MEDIA_CONTROLLER
+  endif
+  ifeq ($(CONFIG_MEDIA_SUPPORT_MODULE),y)
+    ifeq ($(MODULE),y)
+          KBUILD_CFLAGS += -DUSE_MEDIA_CONTROLLER
+    endif
+  endif
+endif
+
 snd-usb-audio-objs := 	card.o \
 			clock.o \
 			endpoint.o \
@@ -13,7 +25,8 @@ snd-usb-audio-objs := 	card.o \
 			pcm.o \
 			proc.o \
 			quirks.o \
-			stream.o
+			stream.o \
+			media.o
 
 snd-usbmidi-lib-objs := midi.o
 
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 1fab977..469d2bf 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -66,6 +66,7 @@
 #include "format.h"
 #include "power.h"
 #include "stream.h"
+#include "media.h"
 
 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
 MODULE_DESCRIPTION("USB Audio");
@@ -619,6 +620,10 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 		list_for_each_entry(mixer, &chip->mixer_list, list) {
 			snd_usb_mixer_disconnect(mixer);
 		}
+		/* Nice to check quirk && quirk->media_device
+		 * need some special handlings. Doesn't look like
+		 * we have access to quirk here */
+		media_device_delete(intf);
 	}
 
 	chip->num_interfaces--;
diff --git a/sound/usb/card.h b/sound/usb/card.h
index ef580b4..235a85f 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -155,6 +155,7 @@ struct snd_usb_substream {
 	} dsd_dop;
 
 	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
+	void *media_ctl;
 };
 
 struct snd_usb_stream {
diff --git a/sound/usb/media.c b/sound/usb/media.c
new file mode 100644
index 0000000..cabbb60
--- /dev/null
+++ b/sound/usb/media.c
@@ -0,0 +1,260 @@
+/*
+ * media.c - Media Controller specific ALSA driver code
+ *
+ * Copyright (c) 2015 Shuah Khan <shuahkh@osg.samsung.com>
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ *
+ * This file is released under the GPLv2.
+ */
+
+/*
+ * This file adds Media Controller support to ALSA driver
+ * to use the Media Controller API to share tuner with DVB
+ * and V4L2 drivers that control media device. Media device
+ * is created based on existing quirks framework. Using this
+ * approach, the media controller API usage can be added for
+ * a specific device.
+*/
+
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/usb.h>
+#include <linux/moduleparam.h>
+#include <linux/mutex.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/module.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/initval.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "midi.h"
+#include "mixer.h"
+#include "proc.h"
+#include "quirks.h"
+#include "endpoint.h"
+#include "helper.h"
+#include "debug.h"
+#include "pcm.h"
+#include "format.h"
+#include "power.h"
+#include "stream.h"
+#include "media.h"
+
+#ifdef USE_MEDIA_CONTROLLER
+int media_device_init(struct usb_interface *iface)
+{
+	struct media_device *mdev;
+	struct usb_device *usbdev = interface_to_usbdev(iface);
+	int ret;
+
+	mdev = media_device_get_devres(&usbdev->dev);
+	if (!mdev)
+		return -ENOMEM;
+	if (!media_devnode_is_registered(&mdev->devnode)) {
+		/* register media device */
+		mdev->dev = &usbdev->dev;
+		if (usbdev->product)
+			strlcpy(mdev->model, usbdev->product,
+				sizeof(mdev->model));
+		if (usbdev->serial)
+			strlcpy(mdev->serial, usbdev->serial,
+				sizeof(mdev->serial));
+		strcpy(mdev->bus_info, usbdev->devpath);
+		mdev->hw_revision = le16_to_cpu(usbdev->descriptor.bcdDevice);
+		ret = media_device_register(mdev);
+		if (ret) {
+			dev_err(&usbdev->dev,
+				"Couldn't create a media device. Error: %d\n",
+				ret);
+			return ret;
+		}
+	}
+	return 0;
+}
+
+void media_device_delete(struct usb_interface *iface)
+{
+	struct media_device *mdev;
+	struct usb_device *usbdev = interface_to_usbdev(iface);
+
+	mdev = media_device_find_devres(&usbdev->dev);
+	if (mdev && media_devnode_is_registered(&mdev->devnode))
+		media_device_unregister(mdev);
+}
+
+static void media_entity_alsa_create_link(struct media_entity *entity,
+					void *notify_data)
+{
+	struct snd_usb_substream *subs;
+	struct media_ctl *mctl;
+	struct media_entity *eptr;
+
+	/* private and mctl should be valid for ALSA DEVNODEs */
+	subs = (struct snd_usb_substream *) notify_data;
+	mctl = (struct media_ctl *) subs->media_ctl;
+
+	if (mctl->decoder_linked)
+		return;
+
+	media_device_for_each_entity(eptr, mctl->media_dev) {
+		if (eptr->type == MEDIA_ENT_T_V4L2_SUBDEV_DECODER) {
+			int i;
+
+			for (i = 0; i < eptr->num_links; i++) {
+				struct media_link *link = &eptr->links[i];
+				struct media_entity *sink = link->sink->entity;
+
+				if (!(link->flags & MEDIA_LNK_FL_ENABLED))
+					continue;
+				if (sink == &mctl->media_entity) {
+					mctl->decoder_linked = 1;
+					mctl->decoder = eptr;
+				}
+			}
+		}
+	}
+}
+
+static void media_enable_tuner(struct media_ctl *mctl)
+{
+	struct media_entity  *source;
+	struct media_link *link, *found_link = NULL;
+	int i, ret, active_links = 0;
+
+	if (!mctl || !mctl->decoder)
+		return;
+
+	for (i = 0; i < mctl->decoder->num_links; i++) {
+		link = &mctl->decoder->links[i];
+		if (link->sink->entity == mctl->decoder) {
+			found_link = link;
+			if (link->flags & MEDIA_LNK_FL_ENABLED)
+				active_links++;
+			break;
+		}
+	}
+
+	if (active_links == 1 || !found_link)
+		return;
+
+	source = found_link->source->entity;
+	for (i = 0; i < source->num_links; i++) {
+		struct media_entity *sink;
+		int flags = 0;
+
+		link = &source->links[i];
+		sink = link->sink->entity;
+
+		if (sink == mctl->decoder)
+			flags = MEDIA_LNK_FL_ENABLED;
+
+		ret = media_entity_setup_link(link, flags);
+		if (ret) {
+			dev_err(mctl->media_dev->dev,
+				"Couldn't change tuner link",
+				"%s->%s to %s. Error %d\n",
+				source->name, sink->name,
+				flags ? "enabled" : "disabled",
+				ret);
+			return;
+		}
+		mctl->tuner_enabled = 1;
+	}
+	dev_info(mctl->media_dev->dev, "Tuner is enabled\n");
+}
+
+void media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
+			int stream)
+{
+	struct media_device *mdev;
+	struct media_ctl *mctl;
+	struct device *pcm_dev = &pcm->streams[stream].dev;
+
+	mdev = media_device_find_devres(&subs->dev->dev);
+	if (!mdev)
+		return;
+
+	if (subs->media_ctl) {
+		/* enable tuner */
+		media_enable_tuner(subs->media_ctl);
+		return;
+	}
+
+	/* allocate media_ctl */
+	mctl = kzalloc(sizeof(struct media_ctl), GFP_KERNEL);
+	if (!mctl)
+		return;
+
+	subs->media_ctl = (void *) mctl;
+	mctl->media_dev = mdev;
+	mctl->entity_notify.notify_data = (void *) subs;
+	mctl->entity_notify.notify = media_entity_alsa_create_link;
+	media_device_register_entity_notify(mctl->media_dev,
+							&mctl->entity_notify);
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+		mctl->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA_PLAYBACK;
+	else
+		mctl->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA_CAPTURE;
+	mctl->media_entity.name = pcm->name;
+	mctl->media_entity.info.dev.major = MAJOR(pcm_dev->devt);
+	mctl->media_entity.info.dev.minor = MINOR(pcm_dev->devt);
+	mctl->media_pad.flags = MEDIA_PAD_FL_SINK;
+	media_entity_init(&mctl->media_entity, 1, &mctl->media_pad, 0);
+	media_device_register_entity(mctl->media_dev, &mctl->media_entity);
+	/* enable tuner */
+	media_enable_tuner(mctl);
+}
+
+void media_stream_delete(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
+
+	if (mctl && mctl->media_dev) {
+		struct media_device *mdev;
+
+		mdev = media_device_find_devres(&subs->dev->dev);
+		if (mdev) {
+			media_entity_remove_links(&mctl->media_entity);
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+			media_device_unregister_entity_notify(mctl->media_dev,
+							&mctl->entity_notify);
+		}
+		mctl->media_dev = NULL;
+		mctl->decoder_linked = 0;
+		mctl->decoder = NULL;
+		mctl->tuner_enabled = 0;
+		kfree(mctl);
+		subs->media_ctl = NULL;
+	}
+}
+
+int media_start_pipeline(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
+	int ret = 0;
+
+	if (mctl && mctl->decoder_linked)
+		ret = media_entity_pipeline_start(&mctl->media_entity,
+							&mctl->media_pipe);
+	return ret;
+}
+
+void media_stop_pipeline(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
+
+	if (mctl && mctl->decoder_linked)
+		media_entity_pipeline_stop(&mctl->media_entity);
+}
+#endif
diff --git a/sound/usb/media.h b/sound/usb/media.h
new file mode 100644
index 0000000..07799b4
--- /dev/null
+++ b/sound/usb/media.h
@@ -0,0 +1,52 @@
+/*
+ * media.h - Media Controller specific ALSA driver code
+ *
+ * Copyright (c) 2015 Shuah Khan <shuahkh@osg.samsung.com>
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ *
+ * This file is released under the GPLv2.
+ */
+
+/*
+ * This file adds Media Controller support to ALSA driver
+ * to use the Media Controller API to share tuner with DVB
+ * and V4L2 drivers that control media device. Media device
+ * is created based on existing quirks framework. Using this
+ * approach, the media controller API usage can be added for
+ * a specific device.
+*/
+#ifndef __MEDIA_H
+
+#ifdef USE_MEDIA_CONTROLLER
+#include <media/media-device.h>
+#include <media/media-entity.h>
+
+struct media_ctl {
+	struct media_device *media_dev;
+	struct media_entity_notify entity_notify;
+	struct media_entity media_entity;
+	struct media_pad media_pad;
+	struct media_pipeline media_pipe;
+	struct media_entity *decoder;
+	bool   decoder_linked;
+	bool   tuner_enabled;
+};
+
+int media_device_init(struct usb_interface *iface);
+void media_device_delete(struct usb_interface *iface);
+void media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
+			int stream);
+void media_stream_delete(struct snd_usb_substream *subs);
+int media_start_pipeline(struct snd_usb_substream *subs);
+void media_stop_pipeline(struct snd_usb_substream *subs);
+#else
+static inline int media_device_init(struct usb_interface *iface) { return 0; }
+static inline void media_device_delete(struct usb_interface *iface) { }
+static inline void media_stream_init(struct snd_usb_substream *subs,
+					struct snd_pcm *pcm, int stream) { }
+static inline void media_stream_delete(struct snd_usb_substream *subs) { }
+static inline int media_start_pipeline(struct snd_usb_substream *subs)
+					{ return 0; }
+static inline void media_stop_pipeline(struct snd_usb_substream *subs) { }
+#endif
+#endif /* __MEDIA_H */
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index b4ef410..0e73a3a 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -35,6 +35,7 @@
 #include "pcm.h"
 #include "clock.h"
 #include "power.h"
+#include "media.h"
 
 #define SUBSTREAM_FLAG_DATA_EP_STARTED	0
 #define SUBSTREAM_FLAG_SYNC_EP_STARTED	1
@@ -1195,6 +1196,7 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_usb_substream *subs = &as->substream[direction];
+	int ret;
 
 	subs->interface = -1;
 	subs->altset_idx = 0;
@@ -1208,7 +1210,10 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
 	subs->dsd_dop.channel = 0;
 	subs->dsd_dop.marker = 1;
 
-	return setup_hw_info(runtime, subs);
+	ret = setup_hw_info(runtime, subs);
+	if (ret == 0)
+		media_stream_init(subs, as->pcm, direction);
+	return ret;
 }
 
 static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
@@ -1587,9 +1592,14 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
 
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
+		err = media_start_pipeline(subs);
+		if (err)
+			return err;
 		err = start_endpoints(subs, false);
-		if (err < 0)
+		if (err < 0) {
+			media_stop_pipeline(subs);
 			return err;
+		}
 
 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
 		subs->running = 1;
@@ -1597,6 +1607,7 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
 	case SNDRV_PCM_TRIGGER_STOP:
 		stop_endpoints(subs, false);
 		subs->running = 0;
+		media_stop_pipeline(subs);
 		return 0;
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		subs->data_endpoint->retire_data_urb = NULL;
diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 2f6d3e9..51c544f 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -2798,6 +2798,7 @@ YAMAHA_DEVICE(0x7010, "UB99"),
 		.product_name = pname, \
 		.ifnum = QUIRK_ANY_INTERFACE, \
 		.type = QUIRK_AUDIO_ALIGN_TRANSFER, \
+		.media_device = 1, \
 	} \
 }
 
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 7c5a701..e9a2009 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -36,6 +36,7 @@
 #include "pcm.h"
 #include "clock.h"
 #include "stream.h"
+#include "media.h"
 
 /*
  * handle the quirks for the contained interfaces
@@ -541,13 +542,19 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
 		[QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk,
 		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
 	};
+	int ret;
 
+	if (quirk->media_device) {
+		/* don't want to fail when media_device_init() doesn't work */
+		media_device_init(iface);
+	}
 	if (quirk->type < QUIRK_TYPE_COUNT) {
-		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
+		ret = quirk_funcs[quirk->type](chip, iface, driver, quirk);
 	} else {
 		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
 		return -ENXIO;
 	}
+	return ret;
 }
 
 /*
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 310a382..6d01c47 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -36,6 +36,7 @@
 #include "format.h"
 #include "clock.h"
 #include "stream.h"
+#include "media.h"
 
 /*
  * free a substream
@@ -52,6 +53,7 @@ static void free_substream(struct snd_usb_substream *subs)
 		kfree(fp);
 	}
 	kfree(subs->rate_list.list);
+	media_stream_delete(subs);
 }
 
 
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 91d0380..c2dbf1d 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -108,6 +108,7 @@ struct snd_usb_audio_quirk {
 	const char *product_name;
 	int16_t ifnum;
 	uint16_t type;
+	bool media_device;
 	const void *data;
 };
 
-- 
2.1.4