[PATCH v2 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API

[PATCH v2 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API

[Shuah Khan]

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 initialze (if necessary) and
register the media device if it isn't already initialized
and 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.

ALSA will attempt to enable the tuner to link the tuner
to the decoder calling enable_source handler if one is
provided by the bridge driver prior to starting Media
pipeline from snd_usb_hw_params(). If enable_source returns
with tuner busy condition, then snd_usb_hw_params() will fail
with -EBUSY. Media pipeline is stopped from snd_usb_hw_free().

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
Changes since v1: Addressed Takasi Iwai's comments on v1
- Move config defines to Kconfig and add logic
  to Makefile to conditionally compile media.c
- Removed extra includes from media.c
- Added snd_usb_autosuspend() in error leg
- Removed debug related code that was missed in v1

 sound/usb/Kconfig        |   7 ++
 sound/usb/Makefile       |   4 +
 sound/usb/card.c         |   7 ++
 sound/usb/card.h         |   1 +
 sound/usb/media.c        | 190 +++++++++++++++++++++++++++++++++++++++++++++++
 sound/usb/media.h        |  56 ++++++++++++++
 sound/usb/pcm.c          |  28 +++++--
 sound/usb/quirks-table.h |   1 +
 sound/usb/quirks.c       |   5 ++
 sound/usb/stream.c       |   2 +
 sound/usb/usbaudio.h     |   1 +
 11 files changed, 297 insertions(+), 5 deletions(-)
 create mode 100644 sound/usb/media.c
 create mode 100644 sound/usb/media.h

diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
index a452ad7..8d5cdab 100644
--- a/sound/usb/Kconfig
+++ b/sound/usb/Kconfig
@@ -15,6 +15,7 @@ config SND_USB_AUDIO
 	select SND_RAWMIDI
 	select SND_PCM
 	select BITREVERSE
+	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE)
 	help
 	  Say Y here to include support for USB audio and USB MIDI
 	  devices.
@@ -22,6 +23,12 @@ config SND_USB_AUDIO
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-usb-audio.
 
+config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
+	bool "USB Audio/MIDI driver with Media Controller Support"
+	depends on SND_USB_AUDIO && MEDIA_CONTROLLER
+	depends on MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE
+	default y
+
 config SND_USB_UA101
 	tristate "Edirol UA-101/UA-1000 driver"
 	select SND_PCM
diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index 2d2d122..3113c45 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile
@@ -15,6 +15,10 @@ snd-usb-audio-objs := 	card.o \
 			quirks.o \
 			stream.o
 
+ifeq ($(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER),y)
+  snd-usb-audio-objs += media.o
+endif
+
 snd-usbmidi-lib-objs := midi.o
 
 # Toplevel Module Dependency
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 18f5664..1a63851 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");
@@ -621,6 +622,12 @@ 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 71778ca..c15a03c 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -156,6 +156,7 @@ 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..644b6e8
--- /dev/null
+++ b/sound/usb/media.c
@@ -0,0 +1,190 @@
+/*
+ * 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/mutex.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#include <sound/pcm.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "media.h"
+
+int media_device_create(struct snd_usb_audio *chip,
+			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 (!mdev->dev) {
+		/* 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_init(mdev);
+		if (ret) {
+			dev_err(&usbdev->dev,
+				"Couldn't create a media device. Error: %d\n",
+				ret);
+			return ret;
+		}
+	}
+	if (!media_devnode_is_registered(&mdev->devnode)) {
+		ret = media_device_register(mdev);
+		if (ret) {
+			dev_err(&usbdev->dev,
+				"Couldn't register 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 int media_enable_source(struct media_ctl *mctl)
+{
+	if (mctl && mctl->media_dev->enable_source)
+		return mctl->media_dev->enable_source(&mctl->media_entity,
+						      &mctl->media_pipe);
+	return 0;
+}
+
+static void media_disable_source(struct media_ctl *mctl)
+{
+	if (mctl && mctl->media_dev->disable_source)
+		mctl->media_dev->disable_source(&mctl->media_entity);
+}
+
+int 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;
+	u32 intf_type;
+	int ret = 0;
+
+	mdev = media_device_find_devres(&subs->dev->dev);
+	if (!mdev)
+		return -ENODEV;
+
+	if (subs->media_ctl)
+		return 0;
+
+	/* allocate media_ctl */
+	mctl = kzalloc(sizeof(*mctl), GFP_KERNEL);
+	if (!mctl)
+		return -ENOMEM;
+
+	mctl->media_dev = mdev;
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		intf_type = MEDIA_INTF_T_ALSA_PCM_PLAYBACK;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_PLAYBACK;
+	} else {
+		intf_type = MEDIA_INTF_T_ALSA_PCM_CAPTURE;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_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_pads_init(&mctl->media_entity, 1, &mctl->media_pad);
+	ret =  media_device_register_entity(mctl->media_dev,
+					    &mctl->media_entity);
+	if (ret) {
+		kfree(mctl);
+		return ret;
+	}
+	mctl->intf_devnode = media_devnode_create(mdev, intf_type, 0,
+						  MAJOR(pcm_dev->devt),
+						  MINOR(pcm_dev->devt));
+	if (!mctl->intf_devnode) {
+		media_device_unregister_entity(&mctl->media_entity);
+		kfree(mctl);
+		return -ENOMEM;
+	}
+	mctl->intf_link = media_create_intf_link(&mctl->media_entity,
+						 &mctl->intf_devnode->intf,
+						 MEDIA_LNK_FL_ENABLED);
+	if (!mctl->intf_link) {
+		media_devnode_remove(mctl->intf_devnode);
+		media_device_unregister_entity(&mctl->media_entity);
+		kfree(mctl);
+		return -ENOMEM;
+	}
+	subs->media_ctl = (void *) mctl;
+	return 0;
+}
+
+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_devnode_remove(mctl->intf_devnode);
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+		}
+		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;
+
+	if (mctl)
+		return media_enable_source(mctl);
+	return 0;
+}
+
+void media_stop_pipeline(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
+
+	if (mctl)
+		media_disable_source(mctl);
+}
diff --git a/sound/usb/media.h b/sound/usb/media.h
new file mode 100644
index 0000000..00b77e6
--- /dev/null
+++ b/sound/usb/media.h
@@ -0,0 +1,56 @@
+/*
+ * 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
+
+#if defined(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) || \
+	defined(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER_MODULE)
+
+#include <media/media-device.h>
+#include <media/media-entity.h>
+
+struct media_ctl {
+	struct media_device *media_dev;
+	struct media_entity media_entity;
+	struct media_intf_devnode *intf_devnode;
+	struct media_link *intf_link;
+	struct media_pad media_pad;
+	struct media_pipeline media_pipe;
+};
+
+int media_device_create(struct snd_usb_audio *chip,
+			struct usb_interface *iface);
+void media_device_delete(struct usb_interface *iface);
+int 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_create(struct snd_usb_audio *chip,
+				      struct usb_interface *iface)
+						{ return 0; }
+static inline void media_device_delete(struct usb_interface *iface) { }
+static inline int media_stream_init(struct snd_usb_substream *subs,
+					struct snd_pcm *pcm, int stream)
+						{ return 0; }
+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 9245f52..c3b8486 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
@@ -715,10 +716,14 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
 	struct audioformat *fmt;
 	int ret;
 
+	ret = media_start_pipeline(subs);
+	if (ret)
+		return ret;
+
 	ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
 					       params_buffer_bytes(hw_params));
 	if (ret < 0)
-		return ret;
+		goto err_ret;
 
 	subs->pcm_format = params_format(hw_params);
 	subs->period_bytes = params_period_bytes(hw_params);
@@ -732,22 +737,27 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
 		dev_dbg(&subs->dev->dev,
 			"cannot set format: format = %#x, rate = %d, channels = %d\n",
 			   subs->pcm_format, subs->cur_rate, subs->channels);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_ret;
 	}
 
 	ret = snd_usb_lock_shutdown(subs->stream->chip);
 	if (ret < 0)
-		return ret;
+		goto err_ret;
 	ret = set_format(subs, fmt);
 	snd_usb_unlock_shutdown(subs->stream->chip);
 	if (ret < 0)
-		return ret;
+		goto err_ret;
 
 	subs->interface = fmt->iface;
 	subs->altset_idx = fmt->altset_idx;
 	subs->need_setup_ep = true;
 
 	return 0;
+
+err_ret:
+	media_stop_pipeline(subs);
+	return ret;
 }
 
 /*
@@ -759,6 +769,7 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)
 {
 	struct snd_usb_substream *subs = substream->runtime->private_data;
 
+	media_stop_pipeline(subs);
 	subs->cur_audiofmt = NULL;
 	subs->cur_rate = 0;
 	subs->period_bytes = 0;
@@ -1219,6 +1230,7 @@ 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;
@@ -1232,7 +1244,12 @@ 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)
+		ret = media_stream_init(subs, as->pcm, direction);
+	if (ret)
+		snd_usb_autosuspend(subs->stream->chip);
+	return ret;
 }
 
 static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
@@ -1241,6 +1258,7 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
 	struct snd_usb_substream *subs = &as->substream[direction];
 
 	stop_endpoints(subs, true);
+	media_stop_pipeline(subs);
 
 	if (subs->interface >= 0 &&
 	    !snd_usb_lock_shutdown(subs->stream->chip)) {
diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 1a1e2e4..8f7b71b 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -2875,6 +2875,7 @@ 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 5ca80e7..b0d9d13 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
@@ -545,6 +546,10 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
 		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
 	};
 
+	if (quirk->media_device) {
+		/* don't want to fail when media_device_create() fails */
+		media_device_create(chip, iface);
+	}
 	if (quirk->type < QUIRK_TYPE_COUNT) {
 		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
 	} else {
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 8ee14f2..789e515 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 15a1271..e3fac29 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -109,6 +109,7 @@ struct snd_usb_audio_quirk {
 	const char *product_name;
 	int16_t ifnum;
 	uint16_t type;
+	bool media_device;
 	const void *data;
 };
 
-- 
2.5.0

Re: [PATCH v2 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API

[Takashi Iwai]

On Thu, 14 Jan 2016 20:52:28 +0100,
Shuah Khan wrote:
> 
> 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 initialze (if necessary) and
> register the media device if it isn't already initialized
> and 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.
> 
> ALSA will attempt to enable the tuner to link the tuner
> to the decoder calling enable_source handler if one is
> provided by the bridge driver prior to starting Media
> pipeline from snd_usb_hw_params(). If enable_source returns
> with tuner busy condition, then snd_usb_hw_params() will fail
> with -EBUSY. Media pipeline is stopped from snd_usb_hw_free().
> 
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> ---
> Changes since v1: Addressed Takasi Iwai's comments on v1
> - Move config defines to Kconfig and add logic
>   to Makefile to conditionally compile media.c
> - Removed extra includes from media.c
> - Added snd_usb_autosuspend() in error leg
> - Removed debug related code that was missed in v1
> 
>  sound/usb/Kconfig        |   7 ++
>  sound/usb/Makefile       |   4 +
>  sound/usb/card.c         |   7 ++
>  sound/usb/card.h         |   1 +
>  sound/usb/media.c        | 190 +++++++++++++++++++++++++++++++++++++++++++++++
>  sound/usb/media.h        |  56 ++++++++++++++
>  sound/usb/pcm.c          |  28 +++++--
>  sound/usb/quirks-table.h |   1 +
>  sound/usb/quirks.c       |   5 ++
>  sound/usb/stream.c       |   2 +
>  sound/usb/usbaudio.h     |   1 +
>  11 files changed, 297 insertions(+), 5 deletions(-)
>  create mode 100644 sound/usb/media.c
>  create mode 100644 sound/usb/media.h
> 
> diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
> index a452ad7..8d5cdab 100644
> --- a/sound/usb/Kconfig
> +++ b/sound/usb/Kconfig
> @@ -15,6 +15,7 @@ config SND_USB_AUDIO
>  	select SND_RAWMIDI
>  	select SND_PCM
>  	select BITREVERSE
> +	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE)

This looks wrong as a Kconfig syntax.  "... if MEDIA_CONTROLLER"
should work, I suppose?

Above all, can MEDIA_CONTROLLER be tristate?  It's currently a bool.
If it's a tristate, it causes a problem wrt dependency.  Imagine
USB-audio is built-in while MC is a module.

>  	help
>  	  Say Y here to include support for USB audio and USB MIDI
>  	  devices.
> @@ -22,6 +23,12 @@ config SND_USB_AUDIO
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called snd-usb-audio.
>  
> +config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
> +	bool "USB Audio/MIDI driver with Media Controller Support"
> +	depends on SND_USB_AUDIO && MEDIA_CONTROLLER
> +	depends on MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE

Hmm, it's superfluous to have both this depends and the reverse-select
of the above.  (And again MEDIA_SUPPORT_MODULE looks bogus.)

> +	default y
> +
>  config SND_USB_UA101
>  	tristate "Edirol UA-101/UA-1000 driver"
>  	select SND_PCM
> diff --git a/sound/usb/Makefile b/sound/usb/Makefile
> index 2d2d122..3113c45 100644
> --- a/sound/usb/Makefile
> +++ b/sound/usb/Makefile
> @@ -15,6 +15,10 @@ snd-usb-audio-objs := 	card.o \
>  			quirks.o \
>  			stream.o
>  
> +ifeq ($(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER),y)
> +  snd-usb-audio-objs += media.o
> +endif

A better form is like

snd-usb-audio-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.


> +
>  snd-usbmidi-lib-objs := midi.o
>  
>  # Toplevel Module Dependency
> diff --git a/sound/usb/card.c b/sound/usb/card.c
> index 18f5664..1a63851 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");
> @@ -621,6 +622,12 @@ 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 71778ca..c15a03c 100644
> --- a/sound/usb/card.h
> +++ b/sound/usb/card.h
> @@ -156,6 +156,7 @@ 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..644b6e8
> --- /dev/null
> +++ b/sound/usb/media.c
> @@ -0,0 +1,190 @@
> +/*
> + * 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/mutex.h>
> +#include <linux/slab.h>
> +#include <linux/usb.h>
> +
> +#include <sound/pcm.h>
> +
> +#include "usbaudio.h"
> +#include "card.h"
> +#include "media.h"
> +
> +int media_device_create(struct snd_usb_audio *chip,
> +			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 (!mdev->dev) {
> +		/* 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_init(mdev);
> +		if (ret) {
> +			dev_err(&usbdev->dev,
> +				"Couldn't create a media device. Error: %d\n",
> +				ret);
> +			return ret;
> +		}
> +	}
> +	if (!media_devnode_is_registered(&mdev->devnode)) {
> +		ret = media_device_register(mdev);
> +		if (ret) {
> +			dev_err(&usbdev->dev,
> +				"Couldn't register 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 int media_enable_source(struct media_ctl *mctl)
> +{
> +	if (mctl && mctl->media_dev->enable_source)
> +		return mctl->media_dev->enable_source(&mctl->media_entity,
> +						      &mctl->media_pipe);
> +	return 0;
> +}
> +
> +static void media_disable_source(struct media_ctl *mctl)
> +{
> +	if (mctl && mctl->media_dev->disable_source)
> +		mctl->media_dev->disable_source(&mctl->media_entity);
> +}
> +
> +int 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;
> +	u32 intf_type;
> +	int ret = 0;
> +
> +	mdev = media_device_find_devres(&subs->dev->dev);
> +	if (!mdev)
> +		return -ENODEV;
> +
> +	if (subs->media_ctl)
> +		return 0;
> +
> +	/* allocate media_ctl */
> +	mctl = kzalloc(sizeof(*mctl), GFP_KERNEL);
> +	if (!mctl)
> +		return -ENOMEM;
> +
> +	mctl->media_dev = mdev;
> +	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
> +		intf_type = MEDIA_INTF_T_ALSA_PCM_PLAYBACK;
> +		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_PLAYBACK;
> +	} else {
> +		intf_type = MEDIA_INTF_T_ALSA_PCM_CAPTURE;
> +		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_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_pads_init(&mctl->media_entity, 1, &mctl->media_pad);
> +	ret =  media_device_register_entity(mctl->media_dev,
> +					    &mctl->media_entity);
> +	if (ret) {
> +		kfree(mctl);
> +		return ret;
> +	}
> +	mctl->intf_devnode = media_devnode_create(mdev, intf_type, 0,
> +						  MAJOR(pcm_dev->devt),
> +						  MINOR(pcm_dev->devt));
> +	if (!mctl->intf_devnode) {
> +		media_device_unregister_entity(&mctl->media_entity);
> +		kfree(mctl);
> +		return -ENOMEM;
> +	}
> +	mctl->intf_link = media_create_intf_link(&mctl->media_entity,
> +						 &mctl->intf_devnode->intf,
> +						 MEDIA_LNK_FL_ENABLED);
> +	if (!mctl->intf_link) {
> +		media_devnode_remove(mctl->intf_devnode);
> +		media_device_unregister_entity(&mctl->media_entity);
> +		kfree(mctl);
> +		return -ENOMEM;
> +	}
> +	subs->media_ctl = (void *) mctl;

The cast to a void pointer is superfluous.


> +	return 0;
> +}
> +
> +void media_stream_delete(struct snd_usb_substream *subs)
> +{
> +	struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;

The cast from a void pointer is superfluous, too.

> +
> +	if (mctl && mctl->media_dev) {
> +		struct media_device *mdev;
> +
> +		mdev = media_device_find_devres(&subs->dev->dev);
> +		if (mdev) {
> +			media_devnode_remove(mctl->intf_devnode);
> +			media_device_unregister_entity(&mctl->media_entity);
> +			media_entity_cleanup(&mctl->media_entity);
> +		}
> +		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;
> +
> +	if (mctl)
> +		return media_enable_source(mctl);
> +	return 0;
> +}
> +
> +void media_stop_pipeline(struct snd_usb_substream *subs)
> +{
> +	struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
> +
> +	if (mctl)
> +		media_disable_source(mctl);
> +}
> diff --git a/sound/usb/media.h b/sound/usb/media.h
> new file mode 100644
> index 0000000..00b77e6
> --- /dev/null
> +++ b/sound/usb/media.h
> @@ -0,0 +1,56 @@
> +/*
> + * 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
> +
> +#if defined(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) || \
> +	defined(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER_MODULE)

The kconfig is a bool.


thanks,

Takashi

> +#include <media/media-device.h>
> +#include <media/media-entity.h>
> +
> +struct media_ctl {
> +	struct media_device *media_dev;
> +	struct media_entity media_entity;
> +	struct media_intf_devnode *intf_devnode;
> +	struct media_link *intf_link;
> +	struct media_pad media_pad;
> +	struct media_pipeline media_pipe;
> +};
> +
> +int media_device_create(struct snd_usb_audio *chip,
> +			struct usb_interface *iface);
> +void media_device_delete(struct usb_interface *iface);
> +int 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_create(struct snd_usb_audio *chip,
> +				      struct usb_interface *iface)
> +						{ return 0; }
> +static inline void media_device_delete(struct usb_interface *iface) { }
> +static inline int media_stream_init(struct snd_usb_substream *subs,
> +					struct snd_pcm *pcm, int stream)
> +						{ return 0; }
> +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 9245f52..c3b8486 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
> @@ -715,10 +716,14 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
>  	struct audioformat *fmt;
>  	int ret;
>  
> +	ret = media_start_pipeline(subs);
> +	if (ret)
> +		return ret;
> +
>  	ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
>  					       params_buffer_bytes(hw_params));
>  	if (ret < 0)
> -		return ret;
> +		goto err_ret;
>  
>  	subs->pcm_format = params_format(hw_params);
>  	subs->period_bytes = params_period_bytes(hw_params);
> @@ -732,22 +737,27 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
>  		dev_dbg(&subs->dev->dev,
>  			"cannot set format: format = %#x, rate = %d, channels = %d\n",
>  			   subs->pcm_format, subs->cur_rate, subs->channels);
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto err_ret;
>  	}
>  
>  	ret = snd_usb_lock_shutdown(subs->stream->chip);
>  	if (ret < 0)
> -		return ret;
> +		goto err_ret;
>  	ret = set_format(subs, fmt);
>  	snd_usb_unlock_shutdown(subs->stream->chip);
>  	if (ret < 0)
> -		return ret;
> +		goto err_ret;
>  
>  	subs->interface = fmt->iface;
>  	subs->altset_idx = fmt->altset_idx;
>  	subs->need_setup_ep = true;
>  
>  	return 0;
> +
> +err_ret:
> +	media_stop_pipeline(subs);
> +	return ret;
>  }
>  
>  /*
> @@ -759,6 +769,7 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)
>  {
>  	struct snd_usb_substream *subs = substream->runtime->private_data;
>  
> +	media_stop_pipeline(subs);
>  	subs->cur_audiofmt = NULL;
>  	subs->cur_rate = 0;
>  	subs->period_bytes = 0;
> @@ -1219,6 +1230,7 @@ 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;
> @@ -1232,7 +1244,12 @@ 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)
> +		ret = media_stream_init(subs, as->pcm, direction);
> +	if (ret)
> +		snd_usb_autosuspend(subs->stream->chip);
> +	return ret;
>  }
>  
>  static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
> @@ -1241,6 +1258,7 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
>  	struct snd_usb_substream *subs = &as->substream[direction];
>  
>  	stop_endpoints(subs, true);
> +	media_stop_pipeline(subs);
>  
>  	if (subs->interface >= 0 &&
>  	    !snd_usb_lock_shutdown(subs->stream->chip)) {
> diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
> index 1a1e2e4..8f7b71b 100644
> --- a/sound/usb/quirks-table.h
> +++ b/sound/usb/quirks-table.h
> @@ -2875,6 +2875,7 @@ 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 5ca80e7..b0d9d13 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
> @@ -545,6 +546,10 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
>  		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
>  	};
>  
> +	if (quirk->media_device) {
> +		/* don't want to fail when media_device_create() fails */
> +		media_device_create(chip, iface);
> +	}
>  	if (quirk->type < QUIRK_TYPE_COUNT) {
>  		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
>  	} else {
> diff --git a/sound/usb/stream.c b/sound/usb/stream.c
> index 8ee14f2..789e515 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 15a1271..e3fac29 100644
> --- a/sound/usb/usbaudio.h
> +++ b/sound/usb/usbaudio.h
> @@ -109,6 +109,7 @@ struct snd_usb_audio_quirk {
>  	const char *product_name;
>  	int16_t ifnum;
>  	uint16_t type;
> +	bool media_device;
>  	const void *data;
>  };
>  
> -- 
> 2.5.0
> 
> 

Re: [PATCH v2 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API

[Shuah Khan]

On 01/15/2016 06:38 AM, Takashi Iwai wrote:
> On Thu, 14 Jan 2016 20:52:28 +0100,
> Shuah Khan wrote:
>>
>> 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 initialze (if necessary) and
>> register the media device if it isn't already initialized
>> and 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.
>>
>> ALSA will attempt to enable the tuner to link the tuner
>> to the decoder calling enable_source handler if one is
>> provided by the bridge driver prior to starting Media
>> pipeline from snd_usb_hw_params(). If enable_source returns
>> with tuner busy condition, then snd_usb_hw_params() will fail
>> with -EBUSY. Media pipeline is stopped from snd_usb_hw_free().
>>
>> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
>> ---
>> Changes since v1: Addressed Takasi Iwai's comments on v1
>> - Move config defines to Kconfig and add logic
>>   to Makefile to conditionally compile media.c
>> - Removed extra includes from media.c
>> - Added snd_usb_autosuspend() in error leg
>> - Removed debug related code that was missed in v1
>>
>>  sound/usb/Kconfig        |   7 ++
>>  sound/usb/Makefile       |   4 +
>>  sound/usb/card.c         |   7 ++
>>  sound/usb/card.h         |   1 +
>>  sound/usb/media.c        | 190 +++++++++++++++++++++++++++++++++++++++++++++++
>>  sound/usb/media.h        |  56 ++++++++++++++
>>  sound/usb/pcm.c          |  28 +++++--
>>  sound/usb/quirks-table.h |   1 +
>>  sound/usb/quirks.c       |   5 ++
>>  sound/usb/stream.c       |   2 +
>>  sound/usb/usbaudio.h     |   1 +
>>  11 files changed, 297 insertions(+), 5 deletions(-)
>>  create mode 100644 sound/usb/media.c
>>  create mode 100644 sound/usb/media.h
>>
>> diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
>> index a452ad7..8d5cdab 100644
>> --- a/sound/usb/Kconfig
>> +++ b/sound/usb/Kconfig
>> @@ -15,6 +15,7 @@ config SND_USB_AUDIO
>>  	select SND_RAWMIDI
>>  	select SND_PCM
>>  	select BITREVERSE
>> +	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE)
> 
> This looks wrong as a Kconfig syntax.  "... if MEDIA_CONTROLLER"
> should work, I suppose?

The conditional select syntax is used in several Kconfig
files. You are right about (MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE)
Adding checks for that is unnecessary.

> 
> Above all, can MEDIA_CONTROLLER be tristate?  It's currently a bool.
> If it's a tristate, it causes a problem wrt dependency.  Imagine
> USB-audio is built-in while MC is a module.

I don't think MEDIA_CONTROLLER will evebr tristate. I have this
logic to the following and it works with and without MEDIA_CONTROLLER

diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
index a452ad7..8ccbb35 100644
--- a/sound/usb/Kconfig
+++ b/sound/usb/Kconfig
@@ -15,6 +15,7 @@ config SND_USB_AUDIO
        select SND_RAWMIDI
        select SND_PCM
        select BITREVERSE
+       select SND_USB_AUDIO_USE_MEDIA_CONTROLLER       if MEDIA_CONTROLLER
        help
          Say Y here to include support for USB audio and USB MIDI
          devices.
@@ -22,6 +23,11 @@ config SND_USB_AUDIO
          To compile this driver as a module, choose M here: the module
          will be called snd-usb-audio.

+config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
+       bool "USB Audio/MIDI driver with Media Controller Support"
+       depends on MEDIA_CONTROLLER
+       default y
+

> 
>>  	help
>>  	  Say Y here to include support for USB audio and USB MIDI
>>  	  devices.
>> @@ -22,6 +23,12 @@ config SND_USB_AUDIO
>>  	  To compile this driver as a module, choose M here: the module
>>  	  will be called snd-usb-audio.
>>  
>> +config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
>> +	bool "USB Audio/MIDI driver with Media Controller Support"
>> +	depends on SND_USB_AUDIO && MEDIA_CONTROLLER
>> +	depends on MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE

See above. I got rid of depends on for SND_USB_AUDIO

> 
> Hmm, it's superfluous to have both this depends and the reverse-select
> of the above.  (And again MEDIA_SUPPORT_MODULE looks bogus.)
> 
>> +	default y
>> +
>>  config SND_USB_UA101
>>  	tristate "Edirol UA-101/UA-1000 driver"
>>  	select SND_PCM
>> diff --git a/sound/usb/Makefile b/sound/usb/Makefile
>> index 2d2d122..3113c45 100644
>> --- a/sound/usb/Makefile
>> +++ b/sound/usb/Makefile
>> @@ -15,6 +15,10 @@ snd-usb-audio-objs := 	card.o \
>>  			quirks.o \
>>  			stream.o
>>  
>> +ifeq ($(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER),y)
>> +  snd-usb-audio-objs += media.o
>> +endif
> 
> A better form is like
> 
> snd-usb-audio-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.

Got it. Fixed it now.

> 
> 
>> +
>>  snd-usbmidi-lib-objs := midi.o
>>  
>>  # Toplevel Module Dependency
>> diff --git a/sound/usb/card.c b/sound/usb/card.c
>> index 18f5664..1a63851 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");
>> @@ -621,6 +622,12 @@ 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 71778ca..c15a03c 100644
>> --- a/sound/usb/card.h
>> +++ b/sound/usb/card.h
>> @@ -156,6 +156,7 @@ 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..644b6e8
>> --- /dev/null
>> +++ b/sound/usb/media.c
>> @@ -0,0 +1,190 @@
>> +/*
>> + * 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/mutex.h>
>> +#include <linux/slab.h>
>> +#include <linux/usb.h>
>> +
>> +#include <sound/pcm.h>
>> +
>> +#include "usbaudio.h"
>> +#include "card.h"
>> +#include "media.h"
>> +
>> +int media_device_create(struct snd_usb_audio *chip,
>> +			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 (!mdev->dev) {
>> +		/* 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_init(mdev);
>> +		if (ret) {
>> +			dev_err(&usbdev->dev,
>> +				"Couldn't create a media device. Error: %d\n",
>> +				ret);
>> +			return ret;
>> +		}
>> +	}
>> +	if (!media_devnode_is_registered(&mdev->devnode)) {
>> +		ret = media_device_register(mdev);
>> +		if (ret) {
>> +			dev_err(&usbdev->dev,
>> +				"Couldn't register 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 int media_enable_source(struct media_ctl *mctl)
>> +{
>> +	if (mctl && mctl->media_dev->enable_source)
>> +		return mctl->media_dev->enable_source(&mctl->media_entity,
>> +						      &mctl->media_pipe);
>> +	return 0;
>> +}
>> +
>> +static void media_disable_source(struct media_ctl *mctl)
>> +{
>> +	if (mctl && mctl->media_dev->disable_source)
>> +		mctl->media_dev->disable_source(&mctl->media_entity);
>> +}
>> +
>> +int 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;
>> +	u32 intf_type;
>> +	int ret = 0;
>> +
>> +	mdev = media_device_find_devres(&subs->dev->dev);
>> +	if (!mdev)
>> +		return -ENODEV;
>> +
>> +	if (subs->media_ctl)
>> +		return 0;
>> +
>> +	/* allocate media_ctl */
>> +	mctl = kzalloc(sizeof(*mctl), GFP_KERNEL);
>> +	if (!mctl)
>> +		return -ENOMEM;
>> +
>> +	mctl->media_dev = mdev;
>> +	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
>> +		intf_type = MEDIA_INTF_T_ALSA_PCM_PLAYBACK;
>> +		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_PLAYBACK;
>> +	} else {
>> +		intf_type = MEDIA_INTF_T_ALSA_PCM_CAPTURE;
>> +		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_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_pads_init(&mctl->media_entity, 1, &mctl->media_pad);
>> +	ret =  media_device_register_entity(mctl->media_dev,
>> +					    &mctl->media_entity);
>> +	if (ret) {
>> +		kfree(mctl);
>> +		return ret;
>> +	}
>> +	mctl->intf_devnode = media_devnode_create(mdev, intf_type, 0,
>> +						  MAJOR(pcm_dev->devt),
>> +						  MINOR(pcm_dev->devt));
>> +	if (!mctl->intf_devnode) {
>> +		media_device_unregister_entity(&mctl->media_entity);
>> +		kfree(mctl);
>> +		return -ENOMEM;
>> +	}
>> +	mctl->intf_link = media_create_intf_link(&mctl->media_entity,
>> +						 &mctl->intf_devnode->intf,
>> +						 MEDIA_LNK_FL_ENABLED);
>> +	if (!mctl->intf_link) {
>> +		media_devnode_remove(mctl->intf_devnode);
>> +		media_device_unregister_entity(&mctl->media_entity);
>> +		kfree(mctl);
>> +		return -ENOMEM;
>> +	}
>> +	subs->media_ctl = (void *) mctl;
> 
> The cast to a void pointer is superfluous.

Right. Fixed it and couple of others like this
one I found.

Will send v3 shortly.

thanks,
-- Shuah

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978

Re: [PATCH v2 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API

[Takashi Iwai]

On Sat, 16 Jan 2016 01:38:27 +0100,
Shuah Khan wrote:
> 
> On 01/15/2016 06:38 AM, Takashi Iwai wrote:
> > On Thu, 14 Jan 2016 20:52:28 +0100,
> > Shuah Khan wrote:
> >>
> >> 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 initialze (if necessary) and
> >> register the media device if it isn't already initialized
> >> and 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.
> >>
> >> ALSA will attempt to enable the tuner to link the tuner
> >> to the decoder calling enable_source handler if one is
> >> provided by the bridge driver prior to starting Media
> >> pipeline from snd_usb_hw_params(). If enable_source returns
> >> with tuner busy condition, then snd_usb_hw_params() will fail
> >> with -EBUSY. Media pipeline is stopped from snd_usb_hw_free().
> >>
> >> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> >> ---
> >> Changes since v1: Addressed Takasi Iwai's comments on v1
> >> - Move config defines to Kconfig and add logic
> >>   to Makefile to conditionally compile media.c
> >> - Removed extra includes from media.c
> >> - Added snd_usb_autosuspend() in error leg
> >> - Removed debug related code that was missed in v1
> >>
> >>  sound/usb/Kconfig        |   7 ++
> >>  sound/usb/Makefile       |   4 +
> >>  sound/usb/card.c         |   7 ++
> >>  sound/usb/card.h         |   1 +
> >>  sound/usb/media.c        | 190 +++++++++++++++++++++++++++++++++++++++++++++++
> >>  sound/usb/media.h        |  56 ++++++++++++++
> >>  sound/usb/pcm.c          |  28 +++++--
> >>  sound/usb/quirks-table.h |   1 +
> >>  sound/usb/quirks.c       |   5 ++
> >>  sound/usb/stream.c       |   2 +
> >>  sound/usb/usbaudio.h     |   1 +
> >>  11 files changed, 297 insertions(+), 5 deletions(-)
> >>  create mode 100644 sound/usb/media.c
> >>  create mode 100644 sound/usb/media.h
> >>
> >> diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
> >> index a452ad7..8d5cdab 100644
> >> --- a/sound/usb/Kconfig
> >> +++ b/sound/usb/Kconfig
> >> @@ -15,6 +15,7 @@ config SND_USB_AUDIO
> >>  	select SND_RAWMIDI
> >>  	select SND_PCM
> >>  	select BITREVERSE
> >> +	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE)
> > 
> > This looks wrong as a Kconfig syntax.  "... if MEDIA_CONTROLLER"
> > should work, I suppose?
> 
> The conditional select syntax is used in several Kconfig
> files. You are right about (MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE)
> Adding checks for that is unnecessary.

Well, my point was that check should be like:
   select SND_USB_AUDIO_XXX if MEDIA_CONTROLLER && MEDIA_SUPPORT

as there is no MEDIA_SUPPORT_MODULE in Kconfig.  It's
MEDIA_SUPPORT=m in Kconfig syntax.  In C code, it's
CONFIG_MEDIA_SUPPORT_MODULE, though.

> > Above all, can MEDIA_CONTROLLER be tristate?  It's currently a bool.
> > If it's a tristate, it causes a problem wrt dependency.  Imagine
> > USB-audio is built-in while MC is a module.
> 
> I don't think MEDIA_CONTROLLER will evebr tristate. I have this
> logic to the following and it works with and without MEDIA_CONTROLLER
> 
> diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
> index a452ad7..8ccbb35 100644
> --- a/sound/usb/Kconfig
> +++ b/sound/usb/Kconfig
> @@ -15,6 +15,7 @@ config SND_USB_AUDIO
>         select SND_RAWMIDI
>         select SND_PCM
>         select BITREVERSE
> +       select SND_USB_AUDIO_USE_MEDIA_CONTROLLER       if MEDIA_CONTROLLER
>         help
>           Say Y here to include support for USB audio and USB MIDI
>           devices.
> @@ -22,6 +23,11 @@ config SND_USB_AUDIO
>           To compile this driver as a module, choose M here: the module
>           will be called snd-usb-audio.
> 
> +config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
> +       bool "USB Audio/MIDI driver with Media Controller Support"
> +       depends on MEDIA_CONTROLLER
> +       default y
> +
> 
> > 
> >>  	help
> >>  	  Say Y here to include support for USB audio and USB MIDI
> >>  	  devices.
> >> @@ -22,6 +23,12 @@ config SND_USB_AUDIO
> >>  	  To compile this driver as a module, choose M here: the module
> >>  	  will be called snd-usb-audio.
> >>  
> >> +config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
> >> +	bool "USB Audio/MIDI driver with Media Controller Support"
> >> +	depends on SND_USB_AUDIO && MEDIA_CONTROLLER
> >> +	depends on MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE
> 
> See above. I got rid of depends on for SND_USB_AUDIO

There is a revere-select, so this menu itself doesn't play any role.

If you want this item selectable, drop select from SND_USB_AUDIO but
just have proper dependencies for this item:

config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
	bool "USB Audio/MIDI driver with Media Controller Support"
	depends on SND_USB_AUDIO
	depends on MEDIA_CONTROLLER
	default y

(Whether default y or not is a remaining question: usually we keep it 
 empty (i.e. no), but I put it here since you had it.)

If you want this auto-selected unconditionally, drop the prompt and
superfluous dependency (and don't set default y):

config SND_USB_AUDIO
	....
	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER
	....

config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
	bool


Takashi

Re: [PATCH v2 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API

[Shuah Khan]

On 01/16/2016 02:06 AM, Takashi Iwai wrote:
> On Sat, 16 Jan 2016 01:38:27 +0100,
> Shuah Khan wrote:
>>
>> On 01/15/2016 06:38 AM, Takashi Iwai wrote:
>>> On Thu, 14 Jan 2016 20:52:28 +0100,
>>> Shuah Khan wrote:
>>>>
>>>> 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 initialze (if necessary) and
>>>> register the media device if it isn't already initialized
>>>> and 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.
>>>>
>>>> ALSA will attempt to enable the tuner to link the tuner
>>>> to the decoder calling enable_source handler if one is
>>>> provided by the bridge driver prior to starting Media
>>>> pipeline from snd_usb_hw_params(). If enable_source returns
>>>> with tuner busy condition, then snd_usb_hw_params() will fail
>>>> with -EBUSY. Media pipeline is stopped from snd_usb_hw_free().
>>>>
>>>> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
>>>> ---
>>>> Changes since v1: Addressed Takasi Iwai's comments on v1
>>>> - Move config defines to Kconfig and add logic
>>>>   to Makefile to conditionally compile media.c
>>>> - Removed extra includes from media.c
>>>> - Added snd_usb_autosuspend() in error leg
>>>> - Removed debug related code that was missed in v1
>>>>
>>>>  sound/usb/Kconfig        |   7 ++
>>>>  sound/usb/Makefile       |   4 +
>>>>  sound/usb/card.c         |   7 ++
>>>>  sound/usb/card.h         |   1 +
>>>>  sound/usb/media.c        | 190 +++++++++++++++++++++++++++++++++++++++++++++++
>>>>  sound/usb/media.h        |  56 ++++++++++++++
>>>>  sound/usb/pcm.c          |  28 +++++--
>>>>  sound/usb/quirks-table.h |   1 +
>>>>  sound/usb/quirks.c       |   5 ++
>>>>  sound/usb/stream.c       |   2 +
>>>>  sound/usb/usbaudio.h     |   1 +
>>>>  11 files changed, 297 insertions(+), 5 deletions(-)
>>>>  create mode 100644 sound/usb/media.c
>>>>  create mode 100644 sound/usb/media.h
>>>>
>>>> diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
>>>> index a452ad7..8d5cdab 100644
>>>> --- a/sound/usb/Kconfig
>>>> +++ b/sound/usb/Kconfig
>>>> @@ -15,6 +15,7 @@ config SND_USB_AUDIO
>>>>  	select SND_RAWMIDI
>>>>  	select SND_PCM
>>>>  	select BITREVERSE
>>>> +	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE)
>>>
>>> This looks wrong as a Kconfig syntax.  "... if MEDIA_CONTROLLER"
>>> should work, I suppose?
>>
>> The conditional select syntax is used in several Kconfig
>> files. You are right about (MEDIA_SUPPORT || MEDIA_SUPPORT_MODULE)
>> Adding checks for that is unnecessary.
> 
> Well, my point was that check should be like:
>    select SND_USB_AUDIO_XXX if MEDIA_CONTROLLER && MEDIA_SUPPORT

Thank you for your patience in helping me through this.

I looked into this more and there is no need to check
for MEDIA_SUPPORT. MEDIA_CONTROLLER defined in

if MEDIA_SUPPORT
endif # MEDIA_SUPPORT

block, checking for MEDIA_SUPPORT is unnecessary.

> 
> There is a revere-select, so this menu itself doesn't play any role.
> 
> If you want this item selectable, drop select from SND_USB_AUDIO but
> just have proper dependencies for this item:

Yes Agreed.

> 
> config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
> 	bool "USB Audio/MIDI driver with Media Controller Support"
> 	depends on SND_USB_AUDIO
> 	depends on MEDIA_CONTROLLER
> 	default y
> 
> (Whether default y or not is a remaining question: usually we keep it 
>  empty (i.e. no), but I put it here since you had it.)
> 
> If you want this auto-selected unconditionally, drop the prompt and
> superfluous dependency (and don't set default y):

Yes I want this auto-selected unconditionally so it won't be
disabled by mistake which would lead to errors because ALSA
will be out of sync with DVB and Analog in the way they try
to get access to media resources.

Yes the below will work.

> 
> config SND_USB_AUDIO
> 	....
> 	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER
> 	....
> 
> config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
> 	bool
> 

thanks,
-- Shuah

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978

[PATCH v2 27/31] sound/usb: Create media mixer function and control interface entities

[Shuah Khan]

Add support for creating MEDIA_ENT_F_AUDIO_MIXER entity for
each mixer and a MEDIA_INTF_T_ALSA_CONTROL control interface
entity that links to mixer entities. MEDIA_INTF_T_ALSA_CONTROL
entity corresponds to the control device for the card.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
Changes since v1:
- Rebase after patch 26 v2 work.
- Fixed warnings in stub defines when
  CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER
  is disabled

 sound/usb/card.c     |  5 +++
 sound/usb/media.c    | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 sound/usb/media.h    | 21 ++++++++++++
 sound/usb/mixer.h    |  1 +
 sound/usb/usbaudio.h |  1 +
 5 files changed, 119 insertions(+)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 1a63851..e965982 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -562,6 +562,9 @@ static int usb_audio_probe(struct usb_interface *intf,
 	if (err < 0)
 		goto __error;
 
+	/* Create media entities for mixer and control dev */
+	media_mixer_init(chip);
+
 	usb_chip[chip->index] = chip;
 	chip->num_interfaces++;
 	usb_set_intfdata(intf, chip);
@@ -618,6 +621,8 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 		list_for_each(p, &chip->midi_list) {
 			snd_usbmidi_disconnect(p);
 		}
+		/* delete mixer media resources */
+		media_mixer_delete(chip);
 		/* release mixer resources */
 		list_for_each_entry(mixer, &chip->mixer_list, list) {
 			snd_usb_mixer_disconnect(mixer);
diff --git a/sound/usb/media.c b/sound/usb/media.c
index 644b6e8..da58378 100644
--- a/sound/usb/media.c
+++ b/sound/usb/media.c
@@ -23,9 +23,11 @@
 #include <linux/usb.h>
 
 #include <sound/pcm.h>
+#include <sound/core.h>
 
 #include "usbaudio.h"
 #include "card.h"
+#include "mixer.h"
 #include "media.h"
 
 int media_device_create(struct snd_usb_audio *chip,
@@ -188,3 +190,92 @@ void media_stop_pipeline(struct snd_usb_substream *subs)
 	if (mctl)
 		media_disable_source(mctl);
 }
+
+int media_mixer_init(struct snd_usb_audio *chip)
+{
+	struct device *ctl_dev = &chip->card->ctl_dev;
+	struct media_intf_devnode *ctl_intf;
+	struct usb_mixer_interface *mixer;
+	struct media_device *mdev;
+	struct media_mixer_ctl *mctl;
+	u32 intf_type = MEDIA_INTF_T_ALSA_CONTROL;
+	int ret;
+
+	mdev = media_device_find_devres(&chip->dev->dev);
+	if (!mdev)
+		return -ENODEV;
+
+	ctl_intf = chip->ctl_intf_media_devnode;
+	if (!ctl_intf) {
+		ctl_intf = (void *) media_devnode_create(mdev,
+							 intf_type, 0,
+							 MAJOR(ctl_dev->devt),
+							 MINOR(ctl_dev->devt));
+		if (!ctl_intf)
+			return -ENOMEM;
+		chip->ctl_intf_media_devnode = ctl_intf;
+	}
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+
+		if (mixer->media_mixer_ctl)
+			continue;
+
+		/* allocate media_mixer_ctl */
+		mctl = kzalloc(sizeof(*mctl), GFP_KERNEL);
+		if (!mctl)
+			return -ENOMEM;
+
+		mctl->media_dev = mdev;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_MIXER;
+		mctl->media_entity.name = chip->card->mixername;
+		mctl->media_pad[0].flags = MEDIA_PAD_FL_SINK;
+		mctl->media_pad[1].flags = MEDIA_PAD_FL_SOURCE;
+		mctl->media_pad[2].flags = MEDIA_PAD_FL_SOURCE;
+		media_entity_pads_init(&mctl->media_entity, MEDIA_MIXER_PAD_MAX,
+				  mctl->media_pad);
+		ret =  media_device_register_entity(mctl->media_dev,
+						    &mctl->media_entity);
+		if (ret) {
+			kfree(mctl);
+			return ret;
+		}
+
+		mctl->intf_link = media_create_intf_link(&mctl->media_entity,
+							 &ctl_intf->intf,
+							 MEDIA_LNK_FL_ENABLED);
+		if (!mctl->intf_link) {
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+			kfree(mctl);
+			return -ENOMEM;
+		}
+		mctl->intf_devnode = ctl_intf;
+		mixer->media_mixer_ctl = (void *) mctl;
+	}
+	return 0;
+}
+
+void media_mixer_delete(struct snd_usb_audio *chip)
+{
+	struct usb_mixer_interface *mixer;
+	struct media_device *mdev;
+
+	mdev = media_device_find_devres(&chip->dev->dev);
+	if (!mdev)
+		return;
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		struct media_mixer_ctl *mctl;
+
+		mctl = (struct media_mixer_ctl *) mixer->media_mixer_ctl;
+		if (!mixer->media_mixer_ctl)
+			continue;
+
+		media_device_unregister_entity(&mctl->media_entity);
+		media_entity_cleanup(&mctl->media_entity);
+		kfree(mctl);
+		mixer->media_mixer_ctl = NULL;
+	}
+	media_devnode_remove(chip->ctl_intf_media_devnode);
+}
diff --git a/sound/usb/media.h b/sound/usb/media.h
index 00b77e6..9477ffa 100644
--- a/sound/usb/media.h
+++ b/sound/usb/media.h
@@ -22,6 +22,7 @@
 
 #include <media/media-device.h>
 #include <media/media-entity.h>
+#include <sound/asound.h>
 
 struct media_ctl {
 	struct media_device *media_dev;
@@ -32,6 +33,22 @@ struct media_ctl {
 	struct media_pipeline media_pipe;
 };
 
+/*
+ * One source pad each for SNDRV_PCM_STREAM_CAPTURE and
+ * SNDRV_PCM_STREAM_PLAYBACK. One for sink pad to link
+ * to AUDIO Source
+*/
+#define MEDIA_MIXER_PAD_MAX    (SNDRV_PCM_STREAM_LAST + 2)
+
+struct media_mixer_ctl {
+	struct media_device *media_dev;
+	struct media_entity media_entity;
+	struct media_intf_devnode *intf_devnode;
+	struct media_link *intf_link;
+	struct media_pad media_pad[MEDIA_MIXER_PAD_MAX];
+	struct media_pipeline media_pipe;
+};
+
 int media_device_create(struct snd_usb_audio *chip,
 			struct usb_interface *iface);
 void media_device_delete(struct usb_interface *iface);
@@ -40,6 +57,8 @@ int media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
 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);
+int media_mixer_init(struct snd_usb_audio *chip);
+void media_mixer_delete(struct snd_usb_audio *chip);
 #else
 static inline int media_device_create(struct snd_usb_audio *chip,
 				      struct usb_interface *iface)
@@ -52,5 +71,7 @@ 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) { }
+static inline int media_mixer_init(struct snd_usb_audio *chip) { return 0; }
+static inline void media_mixer_delete(struct snd_usb_audio *chip) { }
 #endif
 #endif /* __MEDIA_H */
diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
index 3417ef3..787b352 100644
--- a/sound/usb/mixer.h
+++ b/sound/usb/mixer.h
@@ -22,6 +22,7 @@ struct usb_mixer_interface {
 	struct urb *rc_urb;
 	struct usb_ctrlrequest *rc_setup_packet;
 	u8 rc_buffer[6];
+	void *media_mixer_ctl;
 };
 
 #define MAX_CHANNELS	16	/* max logical channels */
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index e3fac29..490b16a 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -60,6 +60,7 @@ struct snd_usb_audio {
 	bool autoclock;			/* from the 'autoclock' module param */
 
 	struct usb_host_interface *ctrl_intf;	/* the audio control interface */
+	void *ctl_intf_media_devnode;
 };
 
 #define usb_audio_err(chip, fmt, args...) \
-- 
2.5.0

[PATCH v2 30/31] sound/usb: Check media device unregister progress state

[Shuah Khan]

Change to release media resources for pcm streams
and mixer before snd_card_disconnect() is done from
usb_audio_disconnect(). The stream and mixer resource
release interfaces access managed media resources
(device resources) created on the usb device parent.
These interfaces should be called before the last
put_device() which releases all the device resources.
In addition, changed the stream and mixer resource
release interfaces to check if media device unregister
is in progress and avoid calling Media Controller API
to unregister entities and remove devnodes. Media device
unregister takes care of all of this. This fixes the
the general protection faults while snd-usb-audio was
cleaning up media resources for pcm streams and mixers.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
Changes since v1:
- Rebased after patch 26 v2 work.
- No changes to patch.

 sound/usb/card.c   |  8 ++++++--
 sound/usb/media.c  | 41 +++++++++++++++++++++++++++++++----------
 sound/usb/media.h  |  4 ++--
 sound/usb/stream.c |  1 -
 4 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index e965982..8959ccb 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -608,6 +608,12 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 		 */
 		wait_event(chip->shutdown_wait,
 			   !atomic_read(&chip->usage_count));
+
+		/* release media pcm stream resources */
+		media_stream_delete(chip);
+		/* delete mixer media resources */
+		media_mixer_delete(chip);
+
 		snd_card_disconnect(card);
 		/* release the pcm resources */
 		list_for_each_entry(as, &chip->pcm_list, list) {
@@ -621,8 +627,6 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 		list_for_each(p, &chip->midi_list) {
 			snd_usbmidi_disconnect(p);
 		}
-		/* delete mixer media resources */
-		media_mixer_delete(chip);
 		/* release mixer resources */
 		list_for_each_entry(mixer, &chip->mixer_list, list) {
 			snd_usb_mixer_disconnect(mixer);
diff --git a/sound/usb/media.c b/sound/usb/media.c
index da58378..93c2bdd 100644
--- a/sound/usb/media.c
+++ b/sound/usb/media.c
@@ -77,8 +77,11 @@ void media_device_delete(struct usb_interface *iface)
 	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);
+	if (mdev) {
+		if (media_devnode_is_registered(&mdev->devnode) &&
+		    !media_device_is_unregister_in_progress(mdev))
+			media_device_unregister(mdev);
+	}
 }
 
 static int media_enable_source(struct media_ctl *mctl)
@@ -156,7 +159,7 @@ int media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
 	return 0;
 }
 
-void media_stream_delete(struct snd_usb_substream *subs)
+static void __media_stream_delete(struct snd_usb_substream *subs)
 {
 	struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
 
@@ -164,7 +167,7 @@ void media_stream_delete(struct snd_usb_substream *subs)
 		struct media_device *mdev;
 
 		mdev = media_device_find_devres(&subs->dev->dev);
-		if (mdev) {
+		if (mdev && !media_device_is_unregister_in_progress(mdev)) {
 			media_devnode_remove(mctl->intf_devnode);
 			media_device_unregister_entity(&mctl->media_entity);
 			media_entity_cleanup(&mctl->media_entity);
@@ -174,6 +177,21 @@ void media_stream_delete(struct snd_usb_substream *subs)
 	}
 }
 
+void media_stream_delete(struct snd_usb_audio *chip)
+{
+	struct snd_usb_stream *as;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		struct snd_usb_substream *subs;
+		int idx;
+
+		for (idx = 0; idx < 2; idx++) {
+			subs = &as->substream[idx];
+			__media_stream_delete(subs);
+		}
+	}
+}
+
 int media_start_pipeline(struct snd_usb_substream *subs)
 {
 	struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
@@ -262,20 +280,23 @@ void media_mixer_delete(struct snd_usb_audio *chip)
 	struct media_device *mdev;
 
 	mdev = media_device_find_devres(&chip->dev->dev);
-	if (!mdev)
-		return;
 
+	if (chip->ctl_intf_media_devnode) {
+		if (mdev && !media_device_is_unregister_in_progress(mdev))
+			media_devnode_remove(chip->ctl_intf_media_devnode);
+		chip->ctl_intf_media_devnode = NULL;
+	}
 	list_for_each_entry(mixer, &chip->mixer_list, list) {
 		struct media_mixer_ctl *mctl;
 
 		mctl = (struct media_mixer_ctl *) mixer->media_mixer_ctl;
 		if (!mixer->media_mixer_ctl)
 			continue;
-
-		media_device_unregister_entity(&mctl->media_entity);
-		media_entity_cleanup(&mctl->media_entity);
+		if (mdev && !media_device_is_unregister_in_progress(mdev)) {
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+		}
 		kfree(mctl);
 		mixer->media_mixer_ctl = NULL;
 	}
-	media_devnode_remove(chip->ctl_intf_media_devnode);
 }
diff --git a/sound/usb/media.h b/sound/usb/media.h
index 9477ffa..09854da 100644
--- a/sound/usb/media.h
+++ b/sound/usb/media.h
@@ -54,7 +54,7 @@ int media_device_create(struct snd_usb_audio *chip,
 void media_device_delete(struct usb_interface *iface);
 int media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
 			int stream);
-void media_stream_delete(struct snd_usb_substream *subs);
+void media_stream_delete(struct snd_usb_audio *chip);
 int media_start_pipeline(struct snd_usb_substream *subs);
 void media_stop_pipeline(struct snd_usb_substream *subs);
 int media_mixer_init(struct snd_usb_audio *chip);
@@ -67,7 +67,7 @@ static inline void media_device_delete(struct usb_interface *iface) { }
 static inline int media_stream_init(struct snd_usb_substream *subs,
 					struct snd_pcm *pcm, int stream)
 						{ return 0; }
-static inline void media_stream_delete(struct snd_usb_substream *subs) { }
+static inline void media_stream_delete(struct snd_usb_audio *chip) { }
 static inline int media_start_pipeline(struct snd_usb_substream *subs)
 					{ return 0; }
 static inline void media_stop_pipeline(struct snd_usb_substream *subs) { }
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 789e515..f96f539 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -53,7 +53,6 @@ static void free_substream(struct snd_usb_substream *subs)
 		kfree(fp);
 	}
 	kfree(subs->rate_list.list);
-	media_stream_delete(subs);
 }
 
 
-- 
2.5.0