Re: [PATCH v6 0/7] MediaTek DVFSRC Bus Bandwidth and Regulator knobs

[AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>]

Il 12/10/24 00:15, Rob Herring ha scritto:
> On Mon, Jun 10, 2024 at 3:57 AM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@collabora.com> wrote:
>>
>> Changes in v6:
>>   - Fixed build with clang (thanks Nathan!)
>>   - Removed unused mtk_rmw() macro in mtk-dvfsrc.c
>>   - Added MODULE_DESCRIPTION() to mtk-dvfsrc-regulator.c
>>
>> Changes in v5:
>>   - Fixed Kconfig dependencies in interconnect
>>   - Fixed module build for dvfsrc and interconnect
>>
>> Changes in v4:
>>   - Updated patch [3/7] to actually remove address/size cells
>>     as the old version got unexpectedly pushed in v3.
>>
>> Changes in v3:
>>   - Removed examples from interconnect and regulator bindings
>>     and kept example node with interconnect and regulator in
>>     the main DVFSRC binding as suggested
>>   - Removed 'reg' from interconnect and regulator, removed both
>>     address and size cells from the main DVFSRC binding as that
>>     was not really needed
>>   - Added anyOf-required entries in the regulator binding as it
>>     doesn't make sense to probe it without any regulator subnode
>>
>> Changes in v2:
>>   - Fixed issues with regulator binding about useless quotes and
>>     wrong binding path (oops)
>>   - Removed useless 'items' from DVFSRC main binding
>>   - Allowed address/size cells to DVFSRC main binding to resolve
>>     validation issues on the regulator and interconnect bindings
>>   - Changed dvfsrc node name to `system-controller`, as the DVFSRC
>>     is actually able to control multiple system components.
>>   - Added a commit to remove mtk-dvfs-regulator.c before adding the
>>     new, refactored regulator driver
>>
>>
>> This series adds support for the MediaTek Dynamic Voltage and Frequency
>> Scaling Resource Controller (DVFSRC), found on many MediaTek SoCs.
>>
>> This hardware collects requests from both software and the various remote
>> processors embededd into the SoC, and decides about a minimum operating
>> voltage and a minimum DRAM frequency to fulfill those requests, in an
>> effort to provide the best achievable performance per watt.
>>
>> Such hardware IP is capable of transparently performing direct register
>> R/W on all of the DVFSRC-controlled regulators and SoC bandwidth knobs.
>>
>> Summarizing how the DVFSRC works for Interconnect:
>>
>>               ICC provider         ICC Nodes
>>                                ----          ----
>>               _________       |CPU |   |--- |VPU |
>>      _____   |         |-----  ----    |     ----
>>     |     |->|  DRAM   |       ----    |     ----
>>     |DRAM |->|scheduler|----- |GPU |   |--- |DISP|
>>     |     |->|  (EMI)  |       ----    |     ----
>>     |_____|->|_________|---.   -----   |     ----
>>                 /|\         `-|MMSYS|--|--- |VDEC|
>>                  |             -----   |     ----
>>                  |                     |     ----
>>                  | change DRAM freq    |--- |VENC|
>>               --------                 |     ----
>>      SMC --> | DVFSRC |                |     ----
>>               --------                 |--- |IMG |
>>                                        |     ----
>>                                        |     ----
>>                                        |--- |CAM |
>>                                              ----
>>
>> ...and for regulators, it's simply...
>>     SMC -> DVFSRC -> Regulator voltage decider -> (vreg) Registers R/W
>>
>> Please note that this series is based on an old (abandoned) series from
>> MediaTek [1], and reuses some parts of the code found in that.
>>
>> Besides, included in this series, there's also a refactoring of the
>> mtk-dvfsrc-regulator driver, which never got compiled at all, and would
>> not build anyway because of missing headers and typos: that commit did
>> not get any Fixes tag because, well, backporting makes no sense at all
>> as the DVFSRC support - which is critical for that driver to work - is
>> introduced with *this series*! :-)
>>
>> P.S.: The DVFSRC regulator is a requirement for the MediaTek UFSHCI
>>        controller's crypto boost feature, which is already upstream but
>>        lacking the actual regulator to work....... :-)
>>
>> [1]: https://lore.kernel.org/all/20210812085846.2628-1-dawei.chien@mediatek.com/
>>
>> AngeloGioacchino Del Regno (7):
>>    dt-bindings: regulator: Add bindings for MediaTek DVFSRC Regulators
>>    dt-bindings: interconnect: Add MediaTek EMI Interconnect bindings
>>    dt-bindings: soc: mediatek: Add DVFSRC bindings for MT8183 and MT8195
>>    soc: mediatek: Add MediaTek DVFS Resource Collector (DVFSRC) driver
> 
> Looks like the driver got picked up, but not the binding.
> mediatek,mt8183-dvfsrc and mediatek,mt8195-dvfsrc show up in next as
> undocumented.
> 
Thanks for making me notice. Adding it up right now.

Cheers,
Angelo