RE: [PATCH 0/6] Ancillary bus implementation and SOF multi-client support

["Rojewski, Cezary" <cezary.rojewski@intel.com>]

On 2020-10-01 12:50 AM, Dave Ertman wrote:
> 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@intel.com/T/#u
> 
> 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.
> 

Given the description and number of possible users, one could safely
say: usage is assured. So, why not submit this bus as a standalone
patch? Isn't it better to first have a stable, complete version present
in Linus' tree and only then append the usage?

All other patches target ASoC SOF solution directly while as stated in
the commit's message, this isn't SOF specific - see the delta provided
at the bottom of cover-letter and a wide range of SOF files it touches.

Czarek


>   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
>