From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
Please note: this patch series depends on [3].
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 In order to provide explicit synchronization between backend and frontend the following changes are introduced in the protocol: - add new ring buffer for sending asynchronous events from backend to frontend to report number of bytes played by the frontend (XENSND_EVT_CUR_POS) - introduce trigger events for playback control: start/stop/pause/resume - add "req-" prefix to event-channel and ring-ref to unify naming of the Xen event channels for requests and events
4. Added explicit back and front parameter negotiation In order to provide explicit stream parameter negotiation between backend and frontend the following changes are introduced in the protocol: add XENSND_OP_HW_PARAM_QUERY request to read/update configuration space for the parameters given: request passes desired parameter's intervals/masks and the response to this request 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): ALSA: xen-front: Introduce Xen para-virtualized sound frontend driver ALSA: xen-front: Read sound driver configuration from Xen store ALSA: xen-front: Implement Xen event channel handling ALSA: xen-front: Implement handling of shared buffers ALSA: xen-front: Implement ALSA virtual sound driver
sound/Kconfig | 2 + sound/Makefile | 2 +- sound/xen/Kconfig | 10 + sound/xen/Makefile | 9 + sound/xen/xen_snd_front.c | 410 +++++++++++++++++++ sound/xen/xen_snd_front.h | 57 +++ sound/xen/xen_snd_front_alsa.c | 830 ++++++++++++++++++++++++++++++++++++++ sound/xen/xen_snd_front_alsa.h | 23 ++ sound/xen/xen_snd_front_cfg.c | 517 ++++++++++++++++++++++++ sound/xen/xen_snd_front_cfg.h | 46 +++ sound/xen/xen_snd_front_evtchnl.c | 478 ++++++++++++++++++++++ sound/xen/xen_snd_front_evtchnl.h | 92 +++++ sound/xen/xen_snd_front_shbuf.c | 193 +++++++++ sound/xen/xen_snd_front_shbuf.h | 36 ++ 14 files changed, 2704 insertions(+), 1 deletion(-) create mode 100644 sound/xen/Kconfig create mode 100644 sound/xen/Makefile create mode 100644 sound/xen/xen_snd_front.c create mode 100644 sound/xen/xen_snd_front.h create mode 100644 sound/xen/xen_snd_front_alsa.c create mode 100644 sound/xen/xen_snd_front_alsa.h create mode 100644 sound/xen/xen_snd_front_cfg.c create mode 100644 sound/xen/xen_snd_front_cfg.h create mode 100644 sound/xen/xen_snd_front_evtchnl.c create mode 100644 sound/xen/xen_snd_front_evtchnl.h create mode 100644 sound/xen/xen_snd_front_shbuf.c create mode 100644 sound/xen/xen_snd_front_shbuf.h