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

[AngeloGioacchino Del Regno]

Il 12/10/24 00:15, Rob Herring ha scritto:
> On Mon, Jun 10, 2024 at 3:57 AM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@xxxxxxxxxxxxx> 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@xxxxxxxxxxxx/
> >
> > 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