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

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