-DaveE > -----Original Message----- > From: Alsa-devel <alsa-devel-bounces@xxxxxxxxxxxxxxxx> On Behalf Of Dave > Ertman > Sent: Wednesday, September 30, 2020 3:51 PM > To: alsa-devel@xxxxxxxxxxxxxxxx > Cc: tiwai@xxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; Sridharan, Ranjani > <ranjani.sridharan@xxxxxxxxx>; pierre-louis.bossart@xxxxxxxxxxxxxxx; > broonie@xxxxxxxxxx; parav@xxxxxxxxxx; jgg@xxxxxxxxxx > Subject: [PATCH 0/6] Ancillary bus implementation and SOF multi-client > support > > Brief history of Ancillary Bus > ============================== > The ancillary bus code was originally submitted upstream as virtual > bus, and was submitted through the netdev tree. This process generated > up to v4. This discussion can be found here: > https://lore.kernel.org/netdev/0200520070227.3392100-2- > jeffrey.t.kirsher@xxxxxxxxx/T/#u Sorry, this is a borked link. Will fix with actual link: https://lore.kernel.org/netdev/20191111192219.30259-1-jeffrey.t.kirsher@xxxxxxxxx/#t this was the original submission of virtual bus in Nov 2019. > > At this point, GregKH requested that we take the review and revision > process to an internal mailing list and garner the buy-in of a respected > kernel contributor. > > The ancillary bus (then known as virtual bus) was originally submitted > along with implementation code for the ice driver and irdma drive, > causing the complication of also having dependencies in the rdma tree. > This new submission is utilizing an ancillary bus consumer in only the > sound driver tree to create the initial implementation and a single > user. > > Since implementation work has started on this patch set, there have been > multiple inquiries about the time frame of its completion. It appears > that there will be numerous consumers of this functionality. > > The process of internal review and implementation using the sound > drivers generated 19 internal versions. The changes, including the name > change from virtual bus to ancillary bus, from these versions can be > summarized as the following: > > - Fixed compilation and checkpatch errors > - Improved documentation to address the motivation for virtual bus. > - Renamed virtual bus to ancillary bus > - increased maximum device name size > - Correct order in Kconfig and Makefile > - removed the mid-layer adev->release layer for device unregister > - pushed adev->id management to parent driver > - all error paths out of ancillary_device_register return error code > - all error paths out of ancillary_device_register use put_device > - added adev->name element > - modname in register cannot be NULL > - added KBUILD_MODNAME as prefix for match_name > - push adev->id responsibility to registering driver > - uevent now parses adev->dev name > - match_id function now parses adev->dev name > - changed drivers probe function to also take an ancillary_device_id param > - split ancillary_device_register into device_initialize and device_add > - adjusted what is done in device_initialize and device_add > - change adev to ancildev and adrv to ancildrv > - change adev to ancildev in documentation > > This submission is the first time that this patch set will be sent to > the alsa-devel mailing list, so it is currently being submitted as > version 1. > > ========================== > > Introduces the ancillary bus implementation along with the example usage > in the Sound Open Firmware(SOF) audio driver. > > In some subsystems, the functionality of the core device > (PCI/ACPI/other) may be too complex for a single device to be managed as > a monolithic block or a part of the functionality might need to be > exposed to a different subsystem. Splitting the functionality into > smaller orthogonal devices makes it easier to manage data, power > management and domain-specific communication with the hardware. Also, > common ancillary_device functionality across primary devices can be > handled by a common ancillary_device. A key requirement for such a split > is that there is no dependency on a physical bus, device, register > accesses or regmap support. These individual devices split from the core > cannot live on the platform bus as they are not physical devices that > are controlled by DT/ACPI. The same argument applies for not using MFD > in this scenario as it relies on individual function devices being > physical devices that are DT enumerated. > > An example for this kind of requirement is the audio subsystem where a > single IP handles multiple entities such as HDMI, Soundwire, local > devices such as mics/speakers etc. The split for the core's > functionality can be arbitrary or be defined by the DSP firmware > topology and include hooks for test/debug. This allows for the audio > core device to be minimal and tightly coupled with handling the > hardware-specific logic and communication. > > The ancillary bus is intended to be minimal, generic and avoid > domain-specific assumptions. Each ancillary bus device represents a part > of its parent functionality. The generic behavior can be extended and > specialized as needed by encapsulating an ancillary bus device within > other domain-specific structures and the use of .ops callbacks. > > The SOF driver adopts the ancillary bus for implementing the > multi-client support. A client in the context of the SOF driver > represents a part of the core device's functionality. It is not a > physical device but rather an ancillary device that needs to communicate > with the DSP via IPCs. With multi-client support,the sound card can be > separated into multiple orthogonal ancillary devices for local devices > (mic/speakers etc), HDMI, sensing, probes, debug etc. In this series, > we demonstrate the usage of the ancillary bus with the help of the IPC > test client which is used for testing the serialization of IPCs when > multiple clients talk to the DSP at the same time. > > Dave Ertman (1): > Add ancillary bus support > > Fred Oh (1): > ASoC: SOF: debug: Remove IPC flood test support in SOF core > > Ranjani Sridharan (4): > ASoC: SOF: Introduce descriptors for SOF client > ASoC: SOF: Create client driver for IPC test > ASoC: SOF: ops: Add ops for client registration > ASoC: SOF: Intel: Define ops for client registration > > Documentation/driver-api/ancillary_bus.rst | 230 +++++++++++++++ > Documentation/driver-api/index.rst | 1 + > drivers/bus/Kconfig | 3 + > drivers/bus/Makefile | 3 + > drivers/bus/ancillary.c | 191 +++++++++++++ > include/linux/ancillary_bus.h | 58 ++++ > include/linux/mod_devicetable.h | 8 + > scripts/mod/devicetable-offsets.c | 3 + > scripts/mod/file2alias.c | 8 + > sound/soc/sof/Kconfig | 29 +- > sound/soc/sof/Makefile | 7 + > sound/soc/sof/core.c | 12 + > sound/soc/sof/debug.c | 230 --------------- > sound/soc/sof/intel/Kconfig | 9 + > sound/soc/sof/intel/Makefile | 3 + > sound/soc/sof/intel/apl.c | 18 ++ > sound/soc/sof/intel/bdw.c | 18 ++ > sound/soc/sof/intel/byt.c | 22 ++ > sound/soc/sof/intel/cnl.c | 18 ++ > sound/soc/sof/intel/intel-client.c | 49 ++++ > sound/soc/sof/intel/intel-client.h | 26 ++ > sound/soc/sof/ops.h | 14 + > sound/soc/sof/sof-client.c | 117 ++++++++ > sound/soc/sof/sof-client.h | 65 +++++ > sound/soc/sof/sof-ipc-test-client.c | 314 +++++++++++++++++++++ > sound/soc/sof/sof-priv.h | 16 +- > 26 files changed, 1233 insertions(+), 239 deletions(-) > create mode 100644 Documentation/driver-api/ancillary_bus.rst > create mode 100644 drivers/bus/ancillary.c > create mode 100644 include/linux/ancillary_bus.h > create mode 100644 sound/soc/sof/intel/intel-client.c > create mode 100644 sound/soc/sof/intel/intel-client.h > create mode 100644 sound/soc/sof/sof-client.c > create mode 100644 sound/soc/sof/sof-client.h > create mode 100644 sound/soc/sof/sof-ipc-test-client.c > > -- > 2.26.2
