On Thu, 21 Jan 2016 19:09:50 +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@xxxxxxxxxxxxxxx>
> ---
> sound/usb/Kconfig | 4 ++
> sound/usb/Makefile | 2 +
> sound/usb/card.c | 7 ++
> sound/usb/card.h | 1 +
> sound/usb/media.c | 184 +++++++++++++++++++++++++++++++++++++++++++++++
> sound/usb/media.h | 55 ++++++++++++++
> 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, 285 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..1a71d93 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 +23,9 @@ 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
> +
> 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..8dca3c4 100644
> --- a/sound/usb/Makefile
> +++ b/sound/usb/Makefile
> @@ -15,6 +15,8 @@ snd-usb-audio-objs := card.o \
> quirks.o \
> stream.o
>
> +snd-usb-audio-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.o
> +
> snd-usbmidi-lib-objs := midi.o
>
> # Toplevel Module Dependency
> diff --git a/sound/usb/card.c b/sound/usb/card.c
> index 1f09d95..3b226ed 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@xxxxxxx>");
> 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..0987f40
> --- /dev/null
> +++ b/sound/usb/media.c
> @@ -0,0 +1,184 @@
> +/*
> + * media.c - Media Controller specific ALSA driver code
> + *
> + * Copyright (c) 2015 Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
> + * 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);
> + media_device_init(mdev);
> + }
> + if (!media_devnode_is_registered(&mdev->devnode)) {
> + ret = media_device_register(mdev);
The device registration in ALSA happens not immediately at the call of
create but triggered via device dev_register callback. I don't think
this would be a big problem but still this may leave some race,
e.g. MC device appears without the actual sound device during probe.
> + 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;
Is it always a sink, no source, no matter which direction, playback or
capture?
thanks,
Takashi
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