Re: [alsa-devel] [PATCH v2 2/2] sound/usb: Update ALSA driver to use media controller API

Em Wed, 03 Jun 2015 09:12:54 -0600 Shuah Khan shuahkh@osg.samsung.com escreveu:

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

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

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 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/Makefile | 3 +- sound/usb/card.c | 5 ++ sound/usb/card.h | 1 + sound/usb/media.c | 181 +++++++++++++++++++++++++++++++++++++++++++++++ sound/usb/media.h | 40 +++++++++++ sound/usb/pcm.c | 10 ++- sound/usb/quirks-table.h | 1 + sound/usb/quirks.c | 9 ++- sound/usb/stream.c | 3 + sound/usb/usbaudio.h | 1 + 10 files changed, 251 insertions(+), 3 deletions(-) create mode 100644 sound/usb/media.c create mode 100644 sound/usb/media.h

diff --git a/sound/usb/Makefile b/sound/usb/Makefile index 2d2d122..7fe4fdd 100644 --- a/sound/usb/Makefile +++ b/sound/usb/Makefile @@ -13,7 +13,8 @@ snd-usb-audio-objs := card.o \ pcm.o \ proc.o \ quirks.o \

• 	stream.o
  

• 	stream.o \
  

• 	media.o
  
  

snd-usbmidi-lib-objs := midi.o

diff --git a/sound/usb/card.c b/sound/usb/card.c index 1fab977..469d2bf 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -66,6 +66,7 @@ #include "format.h" #include "power.h" #include "stream.h" +#include "media.h"

MODULE_AUTHOR("Takashi Iwai tiwai@suse.de"); MODULE_DESCRIPTION("USB Audio"); @@ -619,6 +620,10 @@ static void usb_audio_disconnect(struct usb_interface *intf) list_for_each_entry(mixer, &chip->mixer_list, list) { snd_usb_mixer_disconnect(mixer); }

• /* Nice to check quirk && quirk->media_device
  

•  * need some special handlings. Doesn't look like
  

•  * we have access to quirk here */
  

• media_device_delete(intf);
  

  }

  chip->num_interfaces--;

diff --git a/sound/usb/card.h b/sound/usb/card.h index ef580b4..235a85f 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -155,6 +155,7 @@ struct snd_usb_substream { } dsd_dop;

bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */

• void *media_ctl;

};

struct snd_usb_stream { diff --git a/sound/usb/media.c b/sound/usb/media.c new file mode 100644 index 0000000..8e8a0b3 --- /dev/null +++ b/sound/usb/media.c @@ -0,0 +1,181 @@ +/*

• • media.c - managed media token resource
• • 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.

+*/

+#ifdef CONFIG_MEDIA_CONTROLLER +#if defined(CONFIG_MEDIA_SUPPORT) || \

• (defined(CONFIG_MEDIA_SUPPORT_MODULE) && defined(MODULE))

+#define USE_MEDIA_CONTROLLER +#endif +#endif

+#include <linux/init.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/ctype.h> +#include <linux/usb.h> +#include <linux/moduleparam.h> +#include <linux/mutex.h> +#include <linux/usb/audio.h> +#include <linux/usb/audio-v2.h> +#include <linux/module.h>

+#include <sound/control.h> +#include <sound/core.h> +#include <sound/info.h> +#include <sound/pcm.h> +#include <sound/pcm_params.h> +#include <sound/initval.h>

+#include "usbaudio.h" +#include "card.h" +#include "midi.h" +#include "mixer.h" +#include "proc.h" +#include "quirks.h" +#include "endpoint.h" +#include "helper.h" +#include "debug.h" +#include "pcm.h" +#include "format.h" +#include "power.h" +#include "stream.h" +#include "media.h"

+#ifdef USE_MEDIA_CONTROLLER

Nah. Please move this test to Makefile and add the stubs to media.h header.

+int media_device_init(struct usb_interface *iface) +{

• struct media_device *mdev;
• struct usb_device *usbdev = interface_to_usbdev(iface);
• int ret;
• mdev = media_device_get_devres(&usbdev->dev);
• if (!mdev)

• return -ENOMEM;
  

• if (!media_devnode_is_registered(&mdev->devnode)) {

• /* register media device */
  

• mdev->dev = &usbdev->dev;
  

• if (usbdev->product)
  

• 	strlcpy(mdev->model, usbdev->product,
  

• 		sizeof(mdev->model));
  

• if (usbdev->serial)
  

• 	strlcpy(mdev->serial, usbdev->serial,
  

• 		sizeof(mdev->serial));
  

• strcpy(mdev->bus_info, usbdev->devpath);
  

• mdev->hw_revision = le16_to_cpu(usbdev->descriptor.bcdDevice);
  

• ret = media_device_register(mdev);
  

• if (ret) {
  

• 	dev_err(&usbdev->dev,
  

• 		"Couldn't create a media device. Error: %d\n",
  

• 		ret);
  

• 	return ret;
  

• }
  

• }
• 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_devres(&usbdev->dev);
• if (mdev && media_devnode_is_registered(&mdev->devnode))

• media_device_unregister(mdev);
  

• dev_info(&usbdev->dev, "Deleted media device.\n");

+}

+void media_stream_init(struct snd_usb_substream *subs) +{

• struct media_device *mdev;
• struct media_ctl *mctl;
• struct media_entity *entity;
• int ret;
• mdev = media_device_find_devres(&subs->dev->dev);
• if (!mdev)

• return;
  

• /* allocate media_ctl */
• mctl = kzalloc(sizeof(struct media_ctl), GFP_KERNEL);
• if (!mctl)

• return;
  

• mctl->media_dev = mdev;
• mctl->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA;
• media_entity_init(&mctl->media_entity, 1, &mctl->media_pads, 0);
• media_device_register_entity(mctl->media_dev, &mctl->media_entity);

Looks ok, but we'll likely need to change from DEVNODE_ALSA to something else to reflect what alsa components (sub-devices?) will be actually being registered: mixer, pcm playback, pcm capture, etc;

• media_device_for_each_entity(entity, mctl->media_dev) {

• switch (entity->type) {
  

• case MEDIA_ENT_T_V4L2_SUBDEV_TUNER:
  

• 	ret = media_entity_create_link(entity, 0,
  

• 				 &mctl->media_entity, 0,
  

• 				 MEDIA_LNK_FL_ENABLED);
  

I don't think that this code belongs here.

The proper thing to do seems to add a hook that would be called every time that media_entity_create() is called.

Inside the hook code, if both alsa mixer and tuner are registered, it will create the above link.

Such hook would be registered by some function call. At the time such function would be called, the hook code will also run.

This way, it won't matter if snd-usb-audio is probed before or after au0828.

As the above knowledge is au0828-specifics, the best is to add the hook function caller code inside au0828 driver.

• 	if (ret == 0)
  

• 		mctl->tuner_linked = 1;
  

• break;
  

• }
  

• }
• subs->media_ctl = (void *) mctl;

+}

+void media_stream_delete(struct snd_usb_substream *subs) +{

• struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
• if (mctl && mctl->media_dev) {

• mctl->media_dev = NULL;
  

• mctl->tuner_linked = 0;
  

• media_entity_remove_links(&mctl->media_entity);
  

Hmm... will this work? What happens if just snd-usb-audio is removed, but au0828 keeps loaded?

Laurent knows better than me, but I think this will cause troubles.

• media_device_unregister_entity(&mctl->media_entity);
  

• media_entity_cleanup(&mctl->media_entity);
  

• }

+}

+int media_start_pipeline(struct snd_usb_substream *subs) +{

• struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
• int ret = 0;
• if (mctl && mctl->tuner_linked)

• ret = media_entity_pipeline_start(&mctl->media_entity,
  

• 					&mctl->media_pipe);
  

I think that pipeline start/stop functions need to be modified, as it should start/stop here just the alsa part of the pipeline, not touching at the V4L2 one.

• return ret;

+}

+void media_stop_pipeline(struct snd_usb_substream *subs) +{

• struct media_ctl *mctl = (struct media_ctl *) subs->media_ctl;
• if (mctl && mctl->tuner_linked)

• media_entity_pipeline_stop(&mctl->media_entity);
  

+} +#else +int media_device_init(struct usb_interface *iface) { return 0; }

+void media_device_delete(struct usb_interface *iface) { }

+void media_stream_init(struct snd_usb_substream *subs) { }

+void media_stream_delete(struct snd_usb_substream *subs) { }

+int media_start_pipeline(struct snd_usb_substream *subs) { return 0; }

+void media_stop_pipeline(struct snd_usb_substream *subs) { }

Please put the stubs at the header file.

+#endif diff --git a/sound/usb/media.h b/sound/usb/media.h new file mode 100644 index 0000000..cddc05c --- /dev/null +++ b/sound/usb/media.h @@ -0,0 +1,40 @@ +/*

• • media.h - managed media token resource
• • Copyright (c) 2015 Shuah Khan shuahkh@osg.samsung.com
• • Copyright (c) 2015 Samsung Electronics Co., Ltd.
• • This file is released under the GPLv2.
• */

+/*

• • This file adds Media Controller support to ALSA driver
• • to use the Media Controller API to share tuner with DVB
• • and V4L2 drivers that control media device. Media device
• • is created based on existing quirks framework. Using this
• • approach, the media controller API usage can be added for
• • a specific device.

+*/ +#ifndef __MEDIA_H

+#ifdef USE_MEDIA_CONTROLLER +#include <media/media-device.h> +#include <media/media-entity.h>

+struct media_ctl {

• struct media_device *media_dev;
• struct media_entity media_entity;
• struct media_pad media_pads;
• struct media_pipeline media_pipe;
• bool tuner_linked;

+}; +#endif

+extern int media_device_init(struct usb_interface *iface); +extern void media_device_delete(struct usb_interface *iface); +extern void media_stream_init(struct snd_usb_substream *subs); +extern void media_stream_delete(struct snd_usb_substream *subs); +extern int media_start_pipeline(struct snd_usb_substream *subs); +extern void media_stop_pipeline(struct snd_usb_substream *subs);

+#endif /* __MEDIA_H */ diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index b4ef410..bb83da5 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 @@ -1225,6 +1226,7 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)

subs->pcm_substream = NULL; snd_usb_autosuspend(subs->stream->chip);

• media_stop_pipeline(subs);

  return 0;

} @@ -1587,9 +1589,14 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream

switch (cmd) { case SNDRV_PCM_TRIGGER_START:

• err = media_start_pipeline(subs);
  

• if (err)
  

• 	return err;
  

  err = start_endpoints(subs, false);

• if (err < 0)
  

• if (err < 0) {
  

• 	media_stop_pipeline(subs);
  return err;
  

• }
  
  

  subs->data_endpoint->retire_data_urb = retire_capture_urb; subs->running = 1;

@@ -1597,6 +1604,7 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream case SNDRV_PCM_TRIGGER_STOP: stop_endpoints(subs, false); subs->running = 0;

• media_stop_pipeline(subs);
  

  return 0; case SNDRV_PCM_TRIGGER_PAUSE_PUSH: subs->data_endpoint->retire_data_urb = NULL;

diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h index 2f6d3e9..51c544f 100644 --- a/sound/usb/quirks-table.h +++ b/sound/usb/quirks-table.h @@ -2798,6 +2798,7 @@ YAMAHA_DEVICE(0x7010, "UB99"), .product_name = pname, \ .ifnum = QUIRK_ANY_INTERFACE, \ .type = QUIRK_AUDIO_ALIGN_TRANSFER, \

• .media_device = 1, \
  

  } \

}

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index 46facfc..ea2a9f0 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -36,6 +36,7 @@ #include "pcm.h" #include "clock.h" #include "stream.h" +#include "media.h"

/*

• handle the quirks for the contained interfaces

@@ -541,13 +542,19 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip, [QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk, [QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk, };

• int ret;

• if (quirk->media_device) {

• /* don't want to fail when media_device_init() doesn't work */
  

• media_device_init(iface);
  

• } if (quirk->type < QUIRK_TYPE_COUNT) {

• return quirk_funcs[quirk->type](chip, iface, driver, quirk);
  

• ret = quirk_funcs[quirk->type](chip, iface, driver, quirk);
  

  } else { usb_audio_err(chip, "invalid quirk type %d\n", quirk->type); return -ENXIO; }
• return ret;

}

/* diff --git a/sound/usb/stream.c b/sound/usb/stream.c index 310a382..ab15d9a 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);

}

@@ -104,6 +106,7 @@ 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;

};