Re: [PATCH v2 0/5] ALSA: xen-front: Add Xen para-virtualized frontend driver

[Oleksandr Andrushchenko]

On 04/18/2018 06:15 PM, Oleksandr Andrushchenko wrote:
> On 04/16/2018 09:24 AM, Oleksandr Andrushchenko wrote:
> > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> >
> > Please note: this patch series depends on [3].
> The dependency is now merged into Xen kernel tree [4] for-linus-4.17
The dependency is now pulled into Linus tree [5]
> > This patch series adds support for Xen [1] para-virtualized
> > sound frontend driver. It implements the protocol from
> > include/xen/interface/io/sndif.h with the following limitations:
> > - mute/unmute is not supported
> > - get/set volume is not supported
> > Volume control is not supported for the reason that most of the
> > use-cases (at the moment) are based on scenarious where
> > unprivileged OS (e.g. Android, AGL etc) use software mixers.
> >
> > Both capture and playback are supported.
> >
> > Corresponding backend, implemented as a user-space application, can be
> > found at [2].
> >
> > Thank you,
> > Oleksandr
> >
> > Changes since v1:
> > *****************
> >
> > 1. Moved driver from sound/drivers to sound/xen
> >
> > 2. Coding style changes to better meet Linux Kernel
> >
> > 3. Added explicit back and front synchronization
> > ÂÂÂ In order to provide explicit synchronization between backend and
> > ÂÂÂ frontend the following changes are introduced in the protocol:
> > ÂÂÂÂ - add new ring buffer for sending asynchronous events from
> > ÂÂÂÂÂÂ backend to frontend to report number of bytes played by the
> > ÂÂÂÂÂÂ frontend (XENSND_EVT_CUR_POS)
> > ÂÂÂÂ - introduce trigger events for playback control: 
> > start/stop/pause/resume
> > ÂÂÂÂ - add "req-" prefix to event-channel and ring-ref to unify naming
> > ÂÂÂÂÂÂ of the Xen event channels for requests and events
> >
> > 4. Added explicit back and front parameter negotiation
> > ÂÂÂ In order to provide explicit stream parameter negotiation between
> > ÂÂÂ backend and frontend the following changes are introduced in the 
> > protocol:
> > ÂÂÂ add XENSND_OP_HW_PARAM_QUERY request to read/update
> > ÂÂÂ configuration space for the parameters given: request passes
> > ÂÂÂ desired parameter's intervals/masks and the response to this request
> > ÂÂÂ returns allowed min/max intervals/masks to be used.
> >
> > [1] https://xenproject.org/
> > [2] https://github.com/xen-troops/snd_be
> > [3] https://lkml.org/lkml/2018/4/12/522
> >
> > Oleksandr Andrushchenko (5):
> > ÂÂ ALSA: xen-front: Introduce Xen para-virtualized sound frontend driver
> > ÂÂ ALSA: xen-front: Read sound driver configuration from Xen store
> > ÂÂ ALSA: xen-front: Implement Xen event channel handling
> > ÂÂ ALSA: xen-front: Implement handling of shared buffers
> > ÂÂ ALSA: xen-front: Implement ALSA virtual sound driver
> >
> > Â sound/KconfigÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂ 2 +
> > Â sound/MakefileÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂ 2 +-
> > Â sound/xen/KconfigÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 10 +
> > Â sound/xen/MakefileÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂ 9 +
> > Â sound/xen/xen_snd_front.cÂÂÂÂÂÂÂÂ | 410 +++++++++++++++++++
> > Â sound/xen/xen_snd_front.hÂÂÂÂÂÂÂÂ |Â 57 +++
> > Â sound/xen/xen_snd_front_alsa.cÂÂÂ | 830 
> > ++++++++++++++++++++++++++++++++++++++
> > Â sound/xen/xen_snd_front_alsa.hÂÂÂ |Â 23 ++
> > Â sound/xen/xen_snd_front_cfg.cÂÂÂÂ | 517 ++++++++++++++++++++++++
> > Â sound/xen/xen_snd_front_cfg.hÂÂÂÂ |Â 46 +++
> > Â sound/xen/xen_snd_front_evtchnl.c | 478 ++++++++++++++++++++++
> > Â sound/xen/xen_snd_front_evtchnl.h |Â 92 +++++
> > Â sound/xen/xen_snd_front_shbuf.cÂÂ | 193 +++++++++
> > Â sound/xen/xen_snd_front_shbuf.hÂÂ |Â 36 ++
> > Â 14 files changed, 2704 insertions(+), 1 deletion(-)
> > Â create mode 100644 sound/xen/Kconfig
> > Â create mode 100644 sound/xen/Makefile
> > Â create mode 100644 sound/xen/xen_snd_front.c
> > Â create mode 100644 sound/xen/xen_snd_front.h
> > Â create mode 100644 sound/xen/xen_snd_front_alsa.c
> > Â create mode 100644 sound/xen/xen_snd_front_alsa.h
> > Â create mode 100644 sound/xen/xen_snd_front_cfg.c
> > Â create mode 100644 sound/xen/xen_snd_front_cfg.h
> > Â create mode 100644 sound/xen/xen_snd_front_evtchnl.c
> > Â create mode 100644 sound/xen/xen_snd_front_evtchnl.h
> > Â create mode 100644 sound/xen/xen_snd_front_shbuf.c
> > Â create mode 100644 sound/xen/xen_snd_front_shbuf.h
> [4] 
> https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git/commit/?h=for-linus-4.17&id=cd6e992b3aab072cc90839508aaf5573c8f7e066
[5] 
https://elixir.bootlin.com/linux/v4.17-rc2/source/include/xen/interface/io/sndif.h