[PATCH 0/2] Update ALSA driver to use media controller API

[PATCH 0/2] Update ALSA driver to use media controller API

[Shuah Khan]

This patch series updates ALSA driver to use media controller
API to share tuner with DVB and V4L2 drivers that control AU0828
media device. Two new interfaces are added to media controller
API to enable creating media device as a device resource. This
allows creating media device as a device resource on the main
struct device that is common to all drivers that control a single
media hardware and share resources on it. Drivers then can find
the common media device to register entities and manage links,
and pipelines.

Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
Tested tuner entity doesn't exist case as au0828 v4l2
driver is the one that will create the tuner when it gets
updated to use media controller API.

Please note that au0828 updates media controller are necessary
before the resource sharing can work across ALSA and au0828
dvb and v4l2 drivers. This work is in progress and another
developer is working on it.

Shuah Khan (2):
  media: new media controller API for device resource support
  sound/usb: Update ALSA driver to use media controller API

 drivers/media/media-device.c | 33 +++++++++++++++++++++++++
 include/media/media-device.h |  2 ++
 sound/usb/card.c             |  5 ++++
 sound/usb/card.h             | 12 +++++++++
 sound/usb/pcm.c              | 23 +++++++++++++++++-
 sound/usb/quirks-table.h     |  1 +
 sound/usb/quirks.c           | 58 +++++++++++++++++++++++++++++++++++++++++++-
 sound/usb/quirks.h           |  6 +++++
 sound/usb/stream.c           | 40 ++++++++++++++++++++++++++++++
 sound/usb/usbaudio.h         |  1 +
 10 files changed, 179 insertions(+), 2 deletions(-)

-- 
2.1.4

[PATCH 1/2] media: new media controller API for device resource support

[Shuah Khan]

Add new media controller API to allocate media device as a
device resource. When a media device is created on the main
struct device which is the parent device for the interface
device, it will be available to all drivers associated with
that interface. For example, if a usb media device driver
creates the media device on the main struct device which is
common for all the drivers that control the media device,
including the non-media ALSA driver, media controller API
can be used to share access to the resources on the media
device. This new interface provides the above described
feature. A second interface that finds and returns the media
device is added to allow drivers to find the media device
created by any of the drivers associated with the device.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
 drivers/media/media-device.c | 33 +++++++++++++++++++++++++++++++++
 include/media/media-device.h |  2 ++
 2 files changed, 35 insertions(+)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 7b39440..1c32752 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -462,3 +462,36 @@ void media_device_unregister_entity(struct media_entity *entity)
 	entity->parent = NULL;
 }
 EXPORT_SYMBOL_GPL(media_device_unregister_entity);
+
+static void media_device_release_dr(struct device *dev, void *res)
+{
+}
+
+/*
+ * media_device_get_dr() - get media device as device resource
+ *			creates if one doesn't exist
+*/
+struct media_device *media_device_get_dr(struct device *dev)
+{
+	struct media_device *mdev;
+
+	mdev = devres_find(dev, media_device_release_dr, NULL, NULL);
+	if (mdev)
+		return mdev;
+
+	mdev = devres_alloc(media_device_release_dr,
+				sizeof(struct media_device), GFP_KERNEL);
+	if (!mdev)
+		return NULL;
+	return devres_get(dev, mdev, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(media_device_get_dr);
+
+/*
+ * media_device_find_dr() - find media device as device resource
+*/
+struct media_device *media_device_find_dr(struct device *dev)
+{
+	return devres_find(dev, media_device_release_dr, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(media_device_find_dr);
diff --git a/include/media/media-device.h b/include/media/media-device.h
index 6e6db78..53d0fc3 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -95,6 +95,8 @@ void media_device_unregister(struct media_device *mdev);
 int __must_check media_device_register_entity(struct media_device *mdev,
 					      struct media_entity *entity);
 void media_device_unregister_entity(struct media_entity *entity);
+struct media_device *media_device_get_dr(struct device *dev);
+struct media_device *media_device_find_dr(struct device *dev);
 
 /* Iterate over all entities. */
 #define media_device_for_each_entity(entity, mdev)			\
-- 
2.1.4

[PATCH 1/2] media: new media controller API for device resource support

[Shuah Khan]

Add new media controller API to allocate media device as a
device resource. When a media device is created on the main
struct device which is the parent device for the interface
device, it will be available to all drivers associated with
that interface. For example, if a usb media device driver
creates the media device on the main struct device which is
common for all the drivers that control the media device,
including the non-media ALSA driver, media controller API
can be used to share access to the resources on the media
device. This new interface provides the above described
feature. A second interface that finds and returns the media
device is added to allow drivers to find the media device
created by any of the drivers associated with the device.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
 drivers/media/media-device.c | 33 +++++++++++++++++++++++++++++++++
 include/media/media-device.h |  2 ++
 2 files changed, 35 insertions(+)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 7b39440..1c32752 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -462,3 +462,36 @@ void media_device_unregister_entity(struct media_entity *entity)
 	entity->parent = NULL;
 }
 EXPORT_SYMBOL_GPL(media_device_unregister_entity);
+
+static void media_device_release_dr(struct device *dev, void *res)
+{
+}
+
+/*
+ * media_device_get_dr() - get media device as device resource
+ *			creates if one doesn't exist
+*/
+struct media_device *media_device_get_dr(struct device *dev)
+{
+	struct media_device *mdev;
+
+	mdev = devres_find(dev, media_device_release_dr, NULL, NULL);
+	if (mdev)
+		return mdev;
+
+	mdev = devres_alloc(media_device_release_dr,
+				sizeof(struct media_device), GFP_KERNEL);
+	if (!mdev)
+		return NULL;
+	return devres_get(dev, mdev, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(media_device_get_dr);
+
+/*
+ * media_device_find_dr() - find media device as device resource
+*/
+struct media_device *media_device_find_dr(struct device *dev)
+{
+	return devres_find(dev, media_device_release_dr, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(media_device_find_dr);
diff --git a/include/media/media-device.h b/include/media/media-device.h
index 6e6db78..53d0fc3 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -95,6 +95,8 @@ void media_device_unregister(struct media_device *mdev);
 int __must_check media_device_register_entity(struct media_device *mdev,
 					      struct media_entity *entity);
 void media_device_unregister_entity(struct media_entity *entity);
+struct media_device *media_device_get_dr(struct device *dev);
+struct media_device *media_device_find_dr(struct device *dev);
 
 /* Iterate over all entities. */
 #define media_device_for_each_entity(entity, mdev)			\
-- 
2.1.4

[PATCH 2/2] sound/usb: Update ALSA driver to use media controller API

[Shuah Khan]

Change ALSA driver to use media 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_dr() interface.
media_device_get_dr() will allocate a new media device device
resource or return an existing one if it exists. During probe,
media usb driver could have created the media device. It will
then register the media device if it isn't already registered.
Media device unregister is done from usb_audio_disconnect().

New fields to add support for media entity and links are
added to struct snd_usb_substream. A new media entity for
ALSA and a link from tuner entity to the newly registered
ALSA entity are created from snd_usb_init_substream() and
removed from free_substream(). The state is kept to indicate
if tuner is linked. This is to account for case when tuner
entity doesn't exist. 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
tuner_linked is set.

Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
Tested tuner entity doesn't exist case as au0828 v4l2
driver is the one that will create the tuner when it gets
updated to use media controller API.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
 sound/usb/card.c         |  5 +++++
 sound/usb/card.h         | 12 ++++++++++
 sound/usb/pcm.c          | 23 ++++++++++++++++++-
 sound/usb/quirks-table.h |  1 +
 sound/usb/quirks.c       | 58 +++++++++++++++++++++++++++++++++++++++++++++++-
 sound/usb/quirks.h       |  6 +++++
 sound/usb/stream.c       | 40 +++++++++++++++++++++++++++++++++
 sound/usb/usbaudio.h     |  1 +
 8 files changed, 144 insertions(+), 2 deletions(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 1fab977..587fc24 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -621,6 +621,11 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 		}
 	}
 
+	/* 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--;
 	if (chip->num_interfaces <= 0) {
 		usb_chip[chip->index] = NULL;
diff --git a/sound/usb/card.h b/sound/usb/card.h
index ef580b4..477bdcd 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -1,6 +1,11 @@
 #ifndef __USBAUDIO_CARD_H
 #define __USBAUDIO_CARD_H
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+#include <media/media-device.h>
+#include <media/media-entity.h>
+#endif
+
 #define MAX_NR_RATES	1024
 #define MAX_PACKS	6		/* per URB */
 #define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
@@ -155,6 +160,13 @@ struct snd_usb_substream {
 	} dsd_dop;
 
 	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_device *media_dev;
+	struct media_entity media_entity;
+	struct media_pad media_pads;
+	struct media_pipeline media_pipe;
+	bool   tuner_linked;
+#endif
 };
 
 struct snd_usb_stream {
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index b4ef410..c2a40a9 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1225,6 +1225,10 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
 
 	subs->pcm_substream = NULL;
 	snd_usb_autosuspend(subs->stream->chip);
+#ifdef CONFIG_MEDIA_CONTROLLER
+	if (subs->tuner_linked)
+		media_entity_pipeline_stop(&subs->media_entity);
+#endif
 
 	return 0;
 }
@@ -1587,9 +1591,22 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
 
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
+#ifdef CONFIG_MEDIA_CONTROLLER
+		if (subs->tuner_linked) {
+			err = media_entity_pipeline_start(&subs->media_entity,
+							  &subs->media_pipe);
+			if (err)
+				return err;
+		}
+#endif
 		err = start_endpoints(subs, false);
-		if (err < 0)
+		if (err < 0) {
+#ifdef CONFIG_MEDIA_CONTROLLER
+			if (subs->tuner_linked)
+				media_entity_pipeline_stop(&subs->media_entity);
+#endif
 			return err;
+		}
 
 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
 		subs->running = 1;
@@ -1597,6 +1614,10 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
 	case SNDRV_PCM_TRIGGER_STOP:
 		stop_endpoints(subs, false);
 		subs->running = 0;
+#ifdef CONFIG_MEDIA_CONTROLLER
+		if (subs->tuner_linked)
+			media_entity_pipeline_stop(&subs->media_entity);
+#endif
 		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..468e10f 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -503,6 +503,56 @@ static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
 	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
 }
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+static 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_dr(&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;
+		}
+	}
+	dev_info(&usbdev->dev, "Created media device.\n");
+	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_dr(&usbdev->dev);
+	if (mdev && media_devnode_is_registered(&mdev->devnode))
+		media_device_unregister(mdev);
+	dev_info(&usbdev->dev, "Deleted media device.\n");
+}
+#else
+static inline int media_device_init(struct usb_interface *iface)
+{
+	return 0;
+}
+#endif
+
 /*
  * audio-interface quirks
  *
@@ -541,13 +591,19 @@ 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 */
+		ret = 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/quirks.h b/sound/usb/quirks.h
index 2cd71ed..7782f03 100644
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -40,4 +40,10 @@ u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
 					struct audioformat *fp,
 					unsigned int sample_bytes);
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+void media_device_delete(struct usb_interface *iface);
+#else
+static inline void media_device_delete(struct usb_interface *iface) {}
+#endif
+
 #endif /* __USBAUDIO_QUIRKS_H */
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 310a382..d19f870 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -52,6 +52,17 @@ static void free_substream(struct snd_usb_substream *subs)
 		kfree(fp);
 	}
 	kfree(subs->rate_list.list);
+#ifdef CONFIG_MEDIA_CONTROLLER
+	if (subs->media_dev) {
+		subs->media_dev = NULL;
+		subs->tuner_linked = 0;
+		media_entity_remove_links(&subs->media_entity);
+		media_device_unregister_entity(&subs->media_entity);
+		media_entity_cleanup(&subs->media_entity);
+		pr_info("free_substream(): tuner_linked = %d\n",
+			subs->tuner_linked);
+	}
+#endif
 }
 
 
@@ -75,6 +86,34 @@ static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
 	}
 }
 
+static void media_stream_init(struct snd_usb_substream *subs)
+{
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_entity *entity;
+	int ret;
+
+	subs->media_dev = media_device_find_dr(&subs->dev->dev);
+	if (!subs->media_dev)
+		return;
+	subs->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA;
+	media_entity_init(&subs->media_entity, 1, &subs->media_pads, 0);
+	media_device_register_entity(subs->media_dev, &subs->media_entity);
+	media_device_for_each_entity(entity, subs->media_dev) {
+		switch (entity->type) {
+		case MEDIA_ENT_T_V4L2_SUBDEV_TUNER:
+			ret = media_entity_create_link(entity, 0,
+						 &subs->media_entity, 0,
+						 MEDIA_LNK_FL_ENABLED);
+			if (ret == 0)
+				subs->tuner_linked = 1;
+		break;
+		}
+	}
+	pr_info("media_stream_init(): tuner_linked = %d\n",
+		subs->tuner_linked);
+#endif
+}
+
 /*
  * initialize the substream instance.
  */
@@ -104,6 +143,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as,
 	subs->ep_num = fp->endpoint;
 	if (fp->channels > subs->channels_max)
 		subs->channels_max = fp->channels;
+	media_stream_init(subs);
 }
 
 /* kctl callbacks for usb-audio channel maps */
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

Re: [PATCH 2/2] sound/usb: Update ALSA driver to use media controller API

[Eric Wong]

Shuah Khan <shuahkh@osg.samsung.com> wrote:
> @@ -541,13 +591,19 @@ 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 */
> +		ret = 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;
>  }

What is the point of saving 'ret' of media_device_init if it'll
only be clobbered or ignored for ENXIO?

Re: [PATCH 2/2] sound/usb: Update ALSA driver to use media controller API

[Shuah Khan]

On 05/08/2015 10:51 PM, Eric Wong wrote:
> Shuah Khan <shuahkh@osg.samsung.com> wrote:
>> @@ -541,13 +591,19 @@ 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 */
>> +		ret = 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;
>>  }
> 
> What is the point of saving 'ret' of media_device_init if it'll
> only be clobbered or ignored for ENXIO?
> 

Agreed. There is no point in saving it.

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 0/2] Update ALSA driver to use media controller API

[Shuah Khan]

On 05/08/2015 01:31 PM, Shuah Khan wrote:
> This patch series updates ALSA driver to use media controller
> API to share tuner with DVB and V4L2 drivers that control AU0828
> media device. Two new interfaces are added to media controller
> API to enable creating media device as a device resource. This
> allows creating media device as a device resource on the main
> struct device that is common to all drivers that control a single
> media hardware and share resources on it. Drivers then can find
> the common media device to register entities and manage links,
> and pipelines.
> 
> Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
> Tested tuner entity doesn't exist case as au0828 v4l2
> driver is the one that will create the tuner when it gets
> updated to use media controller API.
> 
> Please note that au0828 updates media controller are necessary
> before the resource sharing can work across ALSA and au0828
> dvb and v4l2 drivers. This work is in progress and another
> developer is working on it.
> 
> Shuah Khan (2):
>   media: new media controller API for device resource support
>   sound/usb: Update ALSA driver to use media controller API
> 
>  drivers/media/media-device.c | 33 +++++++++++++++++++++++++
>  include/media/media-device.h |  2 ++
>  sound/usb/card.c             |  5 ++++
>  sound/usb/card.h             | 12 +++++++++
>  sound/usb/pcm.c              | 23 +++++++++++++++++-
>  sound/usb/quirks-table.h     |  1 +
>  sound/usb/quirks.c           | 58 +++++++++++++++++++++++++++++++++++++++++++-
>  sound/usb/quirks.h           |  6 +++++
>  sound/usb/stream.c           | 40 ++++++++++++++++++++++++++++++
>  sound/usb/usbaudio.h         |  1 +
>  10 files changed, 179 insertions(+), 2 deletions(-)
> 

Hi Mauro, Hans, Pinchart, and Takashi,

Any feedback on this series?

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 2/2] sound/usb: Update ALSA driver to use media controller API

[Takashi Iwai]

At Fri,  8 May 2015 13:31:31 -0600,
Shuah Khan wrote:
> 
> Change ALSA driver to use media 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_dr() interface.
> media_device_get_dr() will allocate a new media device device
> resource or return an existing one if it exists. During probe,
> media usb driver could have created the media device. It will
> then register the media device if it isn't already registered.
> Media device unregister is done from usb_audio_disconnect().
> 
> New fields to add support for media entity and links are
> added to struct snd_usb_substream. A new media entity for
> ALSA and a link from tuner entity to the newly registered
> ALSA entity are created from snd_usb_init_substream() and
> removed from free_substream(). The state is kept to indicate
> if tuner is linked. This is to account for case when tuner
> entity doesn't exist. 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
> tuner_linked is set.
> 
> Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
> Tested tuner entity doesn't exist case as au0828 v4l2
> driver is the one that will create the tuner when it gets
> updated to use media controller API.

I guess it gets broken when CONFIG_MEDIA_SUPPORT=m while
CONFIG_SND*=y.  So, it should be compiled in only when the media
support is built-in or both sound and media are module, i.e.

#ifdef CONFIG_MEDIA_CONTROLLER
#if defined(CONFIG_MEDIA_SUPPORT) || \
    (defined(CONFIG_MEDIA_SUPPORT_MODULE) && defined(MODULE))
#define I_CAN_USE_MEDIA_CONTROLLER
#endif
#endif

> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> ---
>  sound/usb/card.c         |  5 +++++
>  sound/usb/card.h         | 12 ++++++++++
>  sound/usb/pcm.c          | 23 ++++++++++++++++++-
>  sound/usb/quirks-table.h |  1 +
>  sound/usb/quirks.c       | 58 +++++++++++++++++++++++++++++++++++++++++++++++-
>  sound/usb/quirks.h       |  6 +++++
>  sound/usb/stream.c       | 40 +++++++++++++++++++++++++++++++++
>  sound/usb/usbaudio.h     |  1 +
>  8 files changed, 144 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/usb/card.c b/sound/usb/card.c
> index 1fab977..587fc24 100644
> --- a/sound/usb/card.c
> +++ b/sound/usb/card.c
> @@ -621,6 +621,11 @@ static void usb_audio_disconnect(struct usb_interface *intf)
>  		}
>  	}
>  
> +	/* 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);

This should be called once, so better in if (!was_shutdown) block, I
guess.

Apart from that, yes, a good way to call an optional destructor for
quirks would be better.


>  	chip->num_interfaces--;
>  	if (chip->num_interfaces <= 0) {
>  		usb_chip[chip->index] = NULL;
> diff --git a/sound/usb/card.h b/sound/usb/card.h
> index ef580b4..477bdcd 100644
> --- a/sound/usb/card.h
> +++ b/sound/usb/card.h
> @@ -1,6 +1,11 @@
>  #ifndef __USBAUDIO_CARD_H
>  #define __USBAUDIO_CARD_H
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +#include <media/media-device.h>
> +#include <media/media-entity.h>
> +#endif
> +
>  #define MAX_NR_RATES	1024
>  #define MAX_PACKS	6		/* per URB */
>  #define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
> @@ -155,6 +160,13 @@ struct snd_usb_substream {
>  	} dsd_dop;
>  
>  	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	struct media_device *media_dev;
> +	struct media_entity media_entity;
> +	struct media_pad media_pads;
> +	struct media_pipeline media_pipe;
> +	bool   tuner_linked;
> +#endif

Maybe a slightly better idea is to allocate these in a new record and
stores the pointer in stream->media_ctl or whatever new field.
Then, a check like
	if (subs->tuner_linked)
can be replaced with
	if (subs->media_ctl)

The whole media-specific stuff can be gathered in a single file,
e.g. sound/usb/media.c, and there you can define the struct.


>  };
>  
>  struct snd_usb_stream {
> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
> index b4ef410..c2a40a9 100644
> --- a/sound/usb/pcm.c
> +++ b/sound/usb/pcm.c
> @@ -1225,6 +1225,10 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
>  
>  	subs->pcm_substream = NULL;
>  	snd_usb_autosuspend(subs->stream->chip);
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	if (subs->tuner_linked)
> +		media_entity_pipeline_stop(&subs->media_entity);
> +#endif

Let's define each of such call properly and drop ifdef at each place.


>  	return 0;
>  }
> @@ -1587,9 +1591,22 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>  
>  	switch (cmd) {
>  	case SNDRV_PCM_TRIGGER_START:
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +		if (subs->tuner_linked) {
> +			err = media_entity_pipeline_start(&subs->media_entity,
> +							  &subs->media_pipe);
> +			if (err)
> +				return err;
> +		}
> +#endif
>  		err = start_endpoints(subs, false);
> -		if (err < 0)
> +		if (err < 0) {
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +			if (subs->tuner_linked)
> +				media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  			return err;
> +		}
>  
>  		subs->data_endpoint->retire_data_urb = retire_capture_urb;
>  		subs->running = 1;
> @@ -1597,6 +1614,10 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>  	case SNDRV_PCM_TRIGGER_STOP:
>  		stop_endpoints(subs, false);
>  		subs->running = 0;
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +		if (subs->tuner_linked)
> +			media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  		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, \
>  	} \

I guess this could be implemented with QUIRK_COMPOSITE, too, without
adding a new field.  But it might result in too complex code.  Let's
judge it later.


>  }
>  
> diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
> index 7c5a701..468e10f 100644
> --- a/sound/usb/quirks.c
> +++ b/sound/usb/quirks.c
> @@ -503,6 +503,56 @@ static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
>  	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
>  }
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +static 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_dr(&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;
> +		}
> +	}
> +	dev_info(&usbdev->dev, "Created media device.\n");
> +	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_dr(&usbdev->dev);
> +	if (mdev && media_devnode_is_registered(&mdev->devnode))
> +		media_device_unregister(mdev);
> +	dev_info(&usbdev->dev, "Deleted media device.\n");
> +}
> +#else
> +static inline int media_device_init(struct usb_interface *iface)
> +{
> +	return 0;
> +}
> +#endif

Let's move all these media specific code into the single place.


thanks,

Takashi

>  /*
>   * audio-interface quirks
>   *
> @@ -541,13 +591,19 @@ 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 */
> +		ret = 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/quirks.h b/sound/usb/quirks.h
> index 2cd71ed..7782f03 100644
> --- a/sound/usb/quirks.h
> +++ b/sound/usb/quirks.h
> @@ -40,4 +40,10 @@ u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
>  					struct audioformat *fp,
>  					unsigned int sample_bytes);
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +void media_device_delete(struct usb_interface *iface);
> +#else
> +static inline void media_device_delete(struct usb_interface *iface) {}
> +#endif
> +
>  #endif /* __USBAUDIO_QUIRKS_H */
> diff --git a/sound/usb/stream.c b/sound/usb/stream.c
> index 310a382..d19f870 100644
> --- a/sound/usb/stream.c
> +++ b/sound/usb/stream.c
> @@ -52,6 +52,17 @@ static void free_substream(struct snd_usb_substream *subs)
>  		kfree(fp);
>  	}
>  	kfree(subs->rate_list.list);
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	if (subs->media_dev) {
> +		subs->media_dev = NULL;
> +		subs->tuner_linked = 0;
> +		media_entity_remove_links(&subs->media_entity);
> +		media_device_unregister_entity(&subs->media_entity);
> +		media_entity_cleanup(&subs->media_entity);
> +		pr_info("free_substream(): tuner_linked = %d\n",
> +			subs->tuner_linked);
> +	}
> +#endif
>  }
>  
>  
> @@ -75,6 +86,34 @@ static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
>  	}
>  }
>  
> +static void media_stream_init(struct snd_usb_substream *subs)
> +{
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	struct media_entity *entity;
> +	int ret;
> +
> +	subs->media_dev = media_device_find_dr(&subs->dev->dev);
> +	if (!subs->media_dev)
> +		return;
> +	subs->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA;
> +	media_entity_init(&subs->media_entity, 1, &subs->media_pads, 0);
> +	media_device_register_entity(subs->media_dev, &subs->media_entity);
> +	media_device_for_each_entity(entity, subs->media_dev) {
> +		switch (entity->type) {
> +		case MEDIA_ENT_T_V4L2_SUBDEV_TUNER:
> +			ret = media_entity_create_link(entity, 0,
> +						 &subs->media_entity, 0,
> +						 MEDIA_LNK_FL_ENABLED);
> +			if (ret == 0)
> +				subs->tuner_linked = 1;
> +		break;
> +		}
> +	}
> +	pr_info("media_stream_init(): tuner_linked = %d\n",
> +		subs->tuner_linked);
> +#endif
> +}
> +
>  /*
>   * initialize the substream instance.
>   */
> @@ -104,6 +143,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as,
>  	subs->ep_num = fp->endpoint;
>  	if (fp->channels > subs->channels_max)
>  		subs->channels_max = fp->channels;
> +	media_stream_init(subs);
>  }
>  
>  /* kctl callbacks for usb-audio channel maps */
> 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
> 

Re: [PATCH 1/2] media: new media controller API for device resource support

[Hans Verkuil]

On 05/08/2015 09:31 PM, Shuah Khan wrote:
> Add new media controller API to allocate media device as a
> device resource. When a media device is created on the main
> struct device which is the parent device for the interface
> device, it will be available to all drivers associated with
> that interface. For example, if a usb media device driver
> creates the media device on the main struct device which is
> common for all the drivers that control the media device,
> including the non-media ALSA driver, media controller API
> can be used to share access to the resources on the media
> device. This new interface provides the above described
> feature. A second interface that finds and returns the media
> device is added to allow drivers to find the media device
> created by any of the drivers associated with the device.
> 
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> ---
>  drivers/media/media-device.c | 33 +++++++++++++++++++++++++++++++++
>  include/media/media-device.h |  2 ++
>  2 files changed, 35 insertions(+)
> 
> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> index 7b39440..1c32752 100644
> --- a/drivers/media/media-device.c
> +++ b/drivers/media/media-device.c
> @@ -462,3 +462,36 @@ void media_device_unregister_entity(struct media_entity *entity)
>  	entity->parent = NULL;
>  }
>  EXPORT_SYMBOL_GPL(media_device_unregister_entity);
> +
> +static void media_device_release_dr(struct device *dev, void *res)
> +{
> +}
> +
> +/*
> + * media_device_get_dr() - get media device as device resource
> + *			creates if one doesn't exist
> +*/
> +struct media_device *media_device_get_dr(struct device *dev)

I'd use get_devres rather than get_dr. I keep thinking that get_dr means
get_driver. It's too ambiguous, I think.

Regards,

	Hans

> +{
> +	struct media_device *mdev;
> +
> +	mdev = devres_find(dev, media_device_release_dr, NULL, NULL);
> +	if (mdev)
> +		return mdev;
> +
> +	mdev = devres_alloc(media_device_release_dr,
> +				sizeof(struct media_device), GFP_KERNEL);
> +	if (!mdev)
> +		return NULL;
> +	return devres_get(dev, mdev, NULL, NULL);
> +}
> +EXPORT_SYMBOL_GPL(media_device_get_dr);
> +
> +/*
> + * media_device_find_dr() - find media device as device resource
> +*/
> +struct media_device *media_device_find_dr(struct device *dev)
> +{
> +	return devres_find(dev, media_device_release_dr, NULL, NULL);
> +}
> +EXPORT_SYMBOL_GPL(media_device_find_dr);
> diff --git a/include/media/media-device.h b/include/media/media-device.h
> index 6e6db78..53d0fc3 100644
> --- a/include/media/media-device.h
> +++ b/include/media/media-device.h
> @@ -95,6 +95,8 @@ void media_device_unregister(struct media_device *mdev);
>  int __must_check media_device_register_entity(struct media_device *mdev,
>  					      struct media_entity *entity);
>  void media_device_unregister_entity(struct media_entity *entity);
> +struct media_device *media_device_get_dr(struct device *dev);
> +struct media_device *media_device_find_dr(struct device *dev);
>  
>  /* Iterate over all entities. */
>  #define media_device_for_each_entity(entity, mdev)			\
> 

Re: [PATCH 2/2] sound/usb: Update ALSA driver to use media controller API

[Hans Verkuil]

Hi Shuah,

Here are some comments:

On 05/08/2015 09:31 PM, Shuah Khan wrote:
> Change ALSA driver to use media 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_dr() interface.
> media_device_get_dr() will allocate a new media device device
> resource or return an existing one if it exists. During probe,
> media usb driver could have created the media device. It will
> then register the media device if it isn't already registered.
> Media device unregister is done from usb_audio_disconnect().
> 
> New fields to add support for media entity and links are
> added to struct snd_usb_substream. A new media entity for
> ALSA and a link from tuner entity to the newly registered
> ALSA entity are created from snd_usb_init_substream() and
> removed from free_substream(). The state is kept to indicate
> if tuner is linked. This is to account for case when tuner
> entity doesn't exist. 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
> tuner_linked is set.

What happens if you start streaming (TRIGGER START), stop, streaming
(TRIGGER_STOP) and close the pcm? Wouldn't media_entity_pipeline_stop()
be called twice? Or is that harmless?

> 
> Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
> Tested tuner entity doesn't exist case as au0828 v4l2
> driver is the one that will create the tuner when it gets
> updated to use media controller API.
> 
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> ---
>  sound/usb/card.c         |  5 +++++
>  sound/usb/card.h         | 12 ++++++++++
>  sound/usb/pcm.c          | 23 ++++++++++++++++++-
>  sound/usb/quirks-table.h |  1 +
>  sound/usb/quirks.c       | 58 +++++++++++++++++++++++++++++++++++++++++++++++-
>  sound/usb/quirks.h       |  6 +++++
>  sound/usb/stream.c       | 40 +++++++++++++++++++++++++++++++++
>  sound/usb/usbaudio.h     |  1 +
>  8 files changed, 144 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/usb/card.c b/sound/usb/card.c
> index 1fab977..587fc24 100644
> --- a/sound/usb/card.c
> +++ b/sound/usb/card.c
> @@ -621,6 +621,11 @@ static void usb_audio_disconnect(struct usb_interface *intf)
>  		}
>  	}
>  
> +	/* 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--;
>  	if (chip->num_interfaces <= 0) {
>  		usb_chip[chip->index] = NULL;
> diff --git a/sound/usb/card.h b/sound/usb/card.h
> index ef580b4..477bdcd 100644
> --- a/sound/usb/card.h
> +++ b/sound/usb/card.h
> @@ -1,6 +1,11 @@
>  #ifndef __USBAUDIO_CARD_H
>  #define __USBAUDIO_CARD_H
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +#include <media/media-device.h>
> +#include <media/media-entity.h>
> +#endif
> +
>  #define MAX_NR_RATES	1024
>  #define MAX_PACKS	6		/* per URB */
>  #define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
> @@ -155,6 +160,13 @@ struct snd_usb_substream {
>  	} dsd_dop;
>  
>  	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	struct media_device *media_dev;
> +	struct media_entity media_entity;
> +	struct media_pad media_pads;
> +	struct media_pipeline media_pipe;
> +	bool   tuner_linked;
> +#endif
>  };
>  
>  struct snd_usb_stream {
> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
> index b4ef410..c2a40a9 100644
> --- a/sound/usb/pcm.c
> +++ b/sound/usb/pcm.c
> @@ -1225,6 +1225,10 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
>  
>  	subs->pcm_substream = NULL;
>  	snd_usb_autosuspend(subs->stream->chip);
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	if (subs->tuner_linked)
> +		media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  
>  	return 0;
>  }
> @@ -1587,9 +1591,22 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>  
>  	switch (cmd) {
>  	case SNDRV_PCM_TRIGGER_START:
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +		if (subs->tuner_linked) {
> +			err = media_entity_pipeline_start(&subs->media_entity,
> +							  &subs->media_pipe);
> +			if (err)
> +				return err;
> +		}
> +#endif
>  		err = start_endpoints(subs, false);
> -		if (err < 0)
> +		if (err < 0) {
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +			if (subs->tuner_linked)
> +				media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  			return err;
> +		}
>  
>  		subs->data_endpoint->retire_data_urb = retire_capture_urb;
>  		subs->running = 1;
> @@ -1597,6 +1614,10 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>  	case SNDRV_PCM_TRIGGER_STOP:
>  		stop_endpoints(subs, false);
>  		subs->running = 0;
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +		if (subs->tuner_linked)
> +			media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  		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..468e10f 100644
> --- a/sound/usb/quirks.c
> +++ b/sound/usb/quirks.c
> @@ -503,6 +503,56 @@ static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
>  	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
>  }
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +static 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_dr(&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;
> +		}
> +	}
> +	dev_info(&usbdev->dev, "Created media device.\n");
> +	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_dr(&usbdev->dev);
> +	if (mdev && media_devnode_is_registered(&mdev->devnode))
> +		media_device_unregister(mdev);
> +	dev_info(&usbdev->dev, "Deleted media device.\n");
> +}
> +#else
> +static inline int media_device_init(struct usb_interface *iface)
> +{
> +	return 0;
> +}
> +#endif
> +
>  /*
>   * audio-interface quirks
>   *
> @@ -541,13 +591,19 @@ 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 */
> +		ret = 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/quirks.h b/sound/usb/quirks.h
> index 2cd71ed..7782f03 100644
> --- a/sound/usb/quirks.h
> +++ b/sound/usb/quirks.h
> @@ -40,4 +40,10 @@ u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
>  					struct audioformat *fp,
>  					unsigned int sample_bytes);
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +void media_device_delete(struct usb_interface *iface);
> +#else
> +static inline void media_device_delete(struct usb_interface *iface) {}
> +#endif
> +
>  #endif /* __USBAUDIO_QUIRKS_H */
> diff --git a/sound/usb/stream.c b/sound/usb/stream.c
> index 310a382..d19f870 100644
> --- a/sound/usb/stream.c
> +++ b/sound/usb/stream.c
> @@ -52,6 +52,17 @@ static void free_substream(struct snd_usb_substream *subs)
>  		kfree(fp);
>  	}
>  	kfree(subs->rate_list.list);
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	if (subs->media_dev) {
> +		subs->media_dev = NULL;
> +		subs->tuner_linked = 0;
> +		media_entity_remove_links(&subs->media_entity);
> +		media_device_unregister_entity(&subs->media_entity);
> +		media_entity_cleanup(&subs->media_entity);
> +		pr_info("free_substream(): tuner_linked = %d\n",
> +			subs->tuner_linked);
> +	}
> +#endif
>  }
>  
>  
> @@ -75,6 +86,34 @@ static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
>  	}
>  }
>  
> +static void media_stream_init(struct snd_usb_substream *subs)
> +{
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	struct media_entity *entity;
> +	int ret;
> +
> +	subs->media_dev = media_device_find_dr(&subs->dev->dev);
> +	if (!subs->media_dev)
> +		return;
> +	subs->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA;
> +	media_entity_init(&subs->media_entity, 1, &subs->media_pads, 0);
> +	media_device_register_entity(subs->media_dev, &subs->media_entity);
> +	media_device_for_each_entity(entity, subs->media_dev) {
> +		switch (entity->type) {
> +		case MEDIA_ENT_T_V4L2_SUBDEV_TUNER:
> +			ret = media_entity_create_link(entity, 0,
> +						 &subs->media_entity, 0,
> +						 MEDIA_LNK_FL_ENABLED);

I'm pretty sure this will change. It certainly will not work in all cases. There are
devices that have two tuners, one for radio, one for TV. Just just picking the first
one wouldn't be sufficient. However, this is something we will need to discuss as part
of the larger MC discussions. A property might help here.

That said, for now this is OK.

Regards,

	Hans

> +			if (ret == 0)
> +				subs->tuner_linked = 1;
> +		break;
> +		}
> +	}
> +	pr_info("media_stream_init(): tuner_linked = %d\n",
> +		subs->tuner_linked);
> +#endif
> +}
> +
>  /*
>   * initialize the substream instance.
>   */
> @@ -104,6 +143,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as,
>  	subs->ep_num = fp->endpoint;
>  	if (fp->channels > subs->channels_max)
>  		subs->channels_max = fp->channels;
> +	media_stream_init(subs);
>  }
>  
>  /* kctl callbacks for usb-audio channel maps */
> 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;
>  };
>  
> 

Re: [PATCH 2/2] sound/usb: Update ALSA driver to use media controller API

[Shuah Khan]

On 05/27/2015 09:24 AM, Takashi Iwai wrote:
> At Fri,  8 May 2015 13:31:31 -0600,
> Shuah Khan wrote:
>>
>> Change ALSA driver to use media 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_dr() interface.
>> media_device_get_dr() will allocate a new media device device
>> resource or return an existing one if it exists. During probe,
>> media usb driver could have created the media device. It will
>> then register the media device if it isn't already registered.
>> Media device unregister is done from usb_audio_disconnect().
>>
>> New fields to add support for media entity and links are
>> added to struct snd_usb_substream. A new media entity for
>> ALSA and a link from tuner entity to the newly registered
>> ALSA entity are created from snd_usb_init_substream() and
>> removed from free_substream(). The state is kept to indicate
>> if tuner is linked. This is to account for case when tuner
>> entity doesn't exist. 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
>> tuner_linked is set.
>>
>> Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
>> Tested tuner entity doesn't exist case as au0828 v4l2
>> driver is the one that will create the tuner when it gets
>> updated to use media controller API.
> 
> I guess it gets broken when CONFIG_MEDIA_SUPPORT=m while
> CONFIG_SND*=y.  So, it should be compiled in only when the media
> support is built-in or both sound and media are module, i.e.
> 
> #ifdef CONFIG_MEDIA_CONTROLLER
> #if defined(CONFIG_MEDIA_SUPPORT) || \
>     (defined(CONFIG_MEDIA_SUPPORT_MODULE) && defined(MODULE))
> #define I_CAN_USE_MEDIA_CONTROLLER
> #endif
> #endif
> 
>> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
>> ---
>>  sound/usb/card.c         |  5 +++++
>>  sound/usb/card.h         | 12 ++++++++++
>>  sound/usb/pcm.c          | 23 ++++++++++++++++++-
>>  sound/usb/quirks-table.h |  1 +
>>  sound/usb/quirks.c       | 58 +++++++++++++++++++++++++++++++++++++++++++++++-
>>  sound/usb/quirks.h       |  6 +++++
>>  sound/usb/stream.c       | 40 +++++++++++++++++++++++++++++++++
>>  sound/usb/usbaudio.h     |  1 +
>>  8 files changed, 144 insertions(+), 2 deletions(-)
>>
>> diff --git a/sound/usb/card.c b/sound/usb/card.c
>> index 1fab977..587fc24 100644
>> --- a/sound/usb/card.c
>> +++ b/sound/usb/card.c
>> @@ -621,6 +621,11 @@ static void usb_audio_disconnect(struct usb_interface *intf)
>>  		}
>>  	}
>>  
>> +	/* 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);
> 
> This should be called once, so better in if (!was_shutdown) block, I
> guess.

Moved it under if (!was_shutdown) block.

> 
> Apart from that, yes, a good way to call an optional destructor for
> quirks would be better.

Maybe something to look into as an enhancement for quirk handling.

> 
> 
>>  	chip->num_interfaces--;
>>  	if (chip->num_interfaces <= 0) {
>>  		usb_chip[chip->index] = NULL;
>> diff --git a/sound/usb/card.h b/sound/usb/card.h
>> index ef580b4..477bdcd 100644
>> --- a/sound/usb/card.h
>> +++ b/sound/usb/card.h
>> @@ -1,6 +1,11 @@
>>  #ifndef __USBAUDIO_CARD_H
>>  #define __USBAUDIO_CARD_H
>>  
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +#include <media/media-device.h>
>> +#include <media/media-entity.h>
>> +#endif
>> +
>>  #define MAX_NR_RATES	1024
>>  #define MAX_PACKS	6		/* per URB */
>>  #define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
>> @@ -155,6 +160,13 @@ struct snd_usb_substream {
>>  	} dsd_dop;
>>  
>>  	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +	struct media_device *media_dev;
>> +	struct media_entity media_entity;
>> +	struct media_pad media_pads;
>> +	struct media_pipeline media_pipe;
>> +	bool   tuner_linked;
>> +#endif
> 
> Maybe a slightly better idea is to allocate these in a new record and
> stores the pointer in stream->media_ctl or whatever new field.
> Then, a check like
> 	if (subs->tuner_linked)
> can be replaced with
> 	if (subs->media_ctl)
> 
> The whole media-specific stuff can be gathered in a single file,
> e.g. sound/usb/media.c, and there you can define the struct.
> 
> 
>>  };
>>  
>>  struct snd_usb_stream {
>> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
>> index b4ef410..c2a40a9 100644
>> --- a/sound/usb/pcm.c
>> +++ b/sound/usb/pcm.c
>> @@ -1225,6 +1225,10 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
>>  
>>  	subs->pcm_substream = NULL;
>>  	snd_usb_autosuspend(subs->stream->chip);
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +	if (subs->tuner_linked)
>> +		media_entity_pipeline_stop(&subs->media_entity);
>> +#endif
> 
> Let's define each of such call properly and drop ifdef at each place.
> 
> 
>>  	return 0;
>>  }
>> @@ -1587,9 +1591,22 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>>  
>>  	switch (cmd) {
>>  	case SNDRV_PCM_TRIGGER_START:
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +		if (subs->tuner_linked) {
>> +			err = media_entity_pipeline_start(&subs->media_entity,
>> +							  &subs->media_pipe);
>> +			if (err)
>> +				return err;
>> +		}
>> +#endif
>>  		err = start_endpoints(subs, false);
>> -		if (err < 0)
>> +		if (err < 0) {
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +			if (subs->tuner_linked)
>> +				media_entity_pipeline_stop(&subs->media_entity);
>> +#endif
>>  			return err;
>> +		}
>>  
>>  		subs->data_endpoint->retire_data_urb = retire_capture_urb;
>>  		subs->running = 1;
>> @@ -1597,6 +1614,10 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>>  	case SNDRV_PCM_TRIGGER_STOP:
>>  		stop_endpoints(subs, false);
>>  		subs->running = 0;
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +		if (subs->tuner_linked)
>> +			media_entity_pipeline_stop(&subs->media_entity);
>> +#endif
>>  		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, \
>>  	} \
> 
> I guess this could be implemented with QUIRK_COMPOSITE, too, without
> adding a new field.  But it might result in too complex code.  Let's
> judge it later.
> 

I looked into this. Looks like there is one quirk type allowed
at this time. My initial thought was to make .type an array of
quirk types so a device could have multiple quirk types. I opted
to go with the simpler route to add a new field instead.

> 
>>  }
>>  
>> diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
>> index 7c5a701..468e10f 100644
>> --- a/sound/usb/quirks.c
>> +++ b/sound/usb/quirks.c
>> @@ -503,6 +503,56 @@ static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
>>  	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
>>  }
>>  
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +static 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_dr(&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;
>> +		}
>> +	}
>> +	dev_info(&usbdev->dev, "Created media device.\n");
>> +	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_dr(&usbdev->dev);
>> +	if (mdev && media_devnode_is_registered(&mdev->devnode))
>> +		media_device_unregister(mdev);
>> +	dev_info(&usbdev->dev, "Deleted media device.\n");
>> +}
>> +#else
>> +static inline int media_device_init(struct usb_interface *iface)
>> +{
>> +	return 0;
>> +}
>> +#endif
> 
> Let's move all these media specific code into the single place.
> 

Moved all the media specific code into a new file. I will send
v2 that covers Hans's comments as well later on this week.

P.S: Entity part of the code needs updates once Property API
solidifies.

thanks,
-- Shuah


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