Re: [PATCH v4 0/6] Add support i.MX95 BLK CTL module clock features

[Marco Felsch <m.felsch@pengutronix.de>]

On 24-03-18, Peng Fan wrote:
> Hi Marco,
> 
> > Subject: Re: [PATCH v4 0/6] Add support i.MX95 BLK CTL module clock
> > features
> > 
> > Hi Peng,
> > 
> > thank for the patchset.
> > 
> > On 24-03-14, Peng Fan (OSS) wrote:
> > > i.MX95's several MIXes has BLK CTL module which could be used for clk
> > > settings, QoS settings, Misc settings for a MIX. This patchset is to
> > > add the clk feature support, including dt-bindings
> > 
> > I have to ask since there is almost no public documentation available yet. The
> > i.MX95 does have an system-controller for managing pinmux settings and
> > power-domains, right? 
> 
> Yes. 
> 
> If this is the case, why not making use of it via the
> > standard scmi_pm_domain.c driver?
> 
> The SCMI firmware not handle the BLK CTL stuff, but blk ctl stuff is
> a mix of clk, qos, module specific things. It is not good for SCMI firmare
> to handle it.

Currently most of the blk-ctrl users do use the blk-ctrl as power-domain
consumer, except for the isi and the audio part. So as I said above the
scmi_pm_domain.c should be able to supply this. The audio blk-ctrl could
be abstracted via the clk-scmi.c driver. The ISI is another topic.

What you're are going to do here is to put pinctrl etc into SCMI
firmware and power-control into Linux, which sound to me like an 50/50
approach and IMHO is rather sub-optimal. To quote your online available
fact sheet:

8<----------------------------------------------------------
ENERGY FLEX ARCHITECTURE

The i,MX 95 family is designed to be configurable and
scalable, with multiple heterogenous processing domains.
This includes an application domain with up to 6 Arm
Cortex A55 cores, a high-performance real-time domain
with Arm Cortex M7, and low-power/safety domain with
Arm Cortex M33, each able to access interfaces including
CAN-FD, 10GbE networking, PCIe Gen 3 x1 interfaces,
and accelerators such as V2X, ISP, and VPU.
8<----------------------------------------------------------

8<----------------------------------------------------------
HIGH-PERFORMANCE COMPUTE
The i.MX 95 family capabilities include a multi-core
application domain with up to six Arm Cortex®-A55 cores,
as well as two independent real-time domains for
safety/low-power, and high-performance real-time use,
consisting of high-performance Arm Cortex-M7 and
Arm Cortex-M33 CPUs, combining low-power, real-time,
and high-performance processing. The i.MX 95 family is
designed to enable ISO 26262 ASIL-B and SIL-2 IEC 61508
compliant platforms, with the safety domain serving as
a critical capability for many automotive and industrial
applications.
...
8<----------------------------------------------------------

To me this sound like we can turn of the power/clock of an hardware
block which was assigned to a core running SIL-2 certified software from
an non-critical core running Linux if we follow that approach. Also the
SIL-2 software requires the non-critical software to turn on the power
of these hardware blocks. Is this correct?

Regards,
  Marco

> Regards,
> Peng.
> 
> > 
> > Regards,
> >   Marco
> > 
> > 
> > 
> > >
> > > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > > ---
> > > Changes in v4:
> > > - Separate binding doc for each modules, I still keep the syscon as
> > > node name, because the module is not just for clock
> > > - Pass dt-schema check
> > > - Update node compatibles
> > > - Link to v3:
> > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> > > .kernel.org%2Fr%2F20240228-imx95-blk-ctl-v3-0-
> > 40ceba01a211%40nxp.com&d
> > >
> > ata=05%7C02%7Cpeng.fan%40nxp.com%7Caad977d7e4f94c750de408dc469
> > b3952%7C
> > >
> > 686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63846287969085566
> > 1%7CUnknow
> > >
> > n%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1ha
> > WwiLC
> > >
> > JXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=M%2B3lDY9BKvW0nHv4mtvi82RA
> > 9IvYyz72TCbL
> > > UpiYcG0%3D&reserved=0
> > >
> > > Changes in v3:
> > > - Correct example node compatible string
> > > - Pass "make ARCH=arm64 DT_CHECKER_FLAGS=-m -j32 dt_binding_check"
> > > - Link to v2:
> > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> > > .kernel.org%2Fr%2F20240228-imx95-blk-ctl-v2-0-
> > ffb7eefb6dcd%40nxp.com&d
> > >
> > ata=05%7C02%7Cpeng.fan%40nxp.com%7Caad977d7e4f94c750de408dc469
> > b3952%7C
> > >
> > 686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63846287969086560
> > 2%7CUnknow
> > >
> > n%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1ha
> > WwiLC
> > >
> > JXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=4leg49tKhwUMzvD5wlnvgVc7is%2
> > FGMNvpYr6A
> > > %2FAf3OU4%3D&reserved=0
> > >
> > > Changes in v2:
> > > - Correct example node compatible string
> > > - Link to v1:
> > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> > > .kernel.org%2Fr%2F20240228-imx95-blk-ctl-v1-0-
> > 9b5ae3c14d83%40nxp.com&d
> > >
> > ata=05%7C02%7Cpeng.fan%40nxp.com%7Caad977d7e4f94c750de408dc469
> > b3952%7C
> > >
> > 686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63846287969087217
> > 2%7CUnknow
> > >
> > n%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1ha
> > WwiLC
> > >
> > JXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=UuD5MVPFgBqwftuXCIXB7SeGyu0
> > NWPbwY%2Bvy
> > > ChFLyVA%3D&reserved=0
> > >
> > > ---
> > > Peng Fan (6):
> > >       dt-bindindgs: clock: nxp: support i.MX95 VPU CSR module
> > >       dt-bindindgs: clock: nxp: support i.MX95 Camera CSR module
> > >       dt-bindindgs: clock: nxp: support i.MX95 Display Master CSR module
> > >       dt-bindindgs: clock: nxp: support i.MX95 LVDS CSR module
> > >       dt-bindindgs: clock: nxp: support i.MX95 Display CSR module
> > >       clk: imx: add i.MX95 BLK CTL clk driver
> > >
> > >  .../bindings/clock/nxp,imx95-camera-csr.yaml       |  50 +++
> > >  .../bindings/clock/nxp,imx95-display-csr.yaml      |  50 +++
> > >  .../clock/nxp,imx95-display-master-csr.yaml        |  62 +++
> > >  .../bindings/clock/nxp,imx95-lvds-csr.yaml         |  50 +++
> > >  .../bindings/clock/nxp,imx95-vpu-csr.yaml          |  50 +++
> > >  drivers/clk/imx/Kconfig                            |   7 +
> > >  drivers/clk/imx/Makefile                           |   1 +
> > >  drivers/clk/imx/clk-imx95-blk-ctl.c                | 438 +++++++++++++++++++++
> > >  include/dt-bindings/clock/nxp,imx95-clock.h        |  32 ++
> > >  9 files changed, 740 insertions(+)
> > > ---
> > > base-commit: c9c32620af65fee2b1ac8390fe1349b33f9d0888
> > > change-id: 20240228-imx95-blk-ctl-9ef8c1fc4c22
> > >
> > > Best regards,
> > > --
> > > Peng Fan <peng.fan@nxp.com>
> > >
> > >
> > >
>