Re: [PATCH 1/4] firmware: arm_scmi: bus: Bypass setting fwnode for scmi cpufreq

On Wed, Feb 12, 2025 at 03:01:20PM +0800, Peng Fan wrote:

On Tue, Feb 11, 2025 at 05:13:21PM +0000, Sudeep Holla wrote:

quoted

On Wed, Dec 25, 2024 at 04:20:44PM +0800, Peng Fan (OSS) wrote:

quoted

From: Peng Fan <peng.fan@nxp.com>

Two drivers scmi_cpufreq.c and scmi_perf_domain.c both use
SCMI_PROTCOL_PERF protocol, but with different name, so two scmi devices
will be created. But the fwnode->dev could only point to one device.

If scmi cpufreq device created earlier, the fwnode->dev will point to
the scmi cpufreq device. Then the fw_devlink will link performance
domain user device(consumer) to the scmi cpufreq device(supplier).
But actually the performance domain user device, such as GPU, should use
the scmi perf device as supplier. Also if 'cpufreq.off=1' in bootargs,
the GPU driver will defer probe always, because of the scmi cpufreq
device not ready.

Because for cpufreq, no need use fw_devlink. So bypass setting fwnode
for scmi cpufreq device.

Not 100% sure if above is correct. See:

Commit 8410e7f3b31e ("cpufreq: scmi: Fix OPP addition failure with a dummy clock provider")

Am I missing something ?

Could we update juno-scmi.dtsi to use ?

 &A53_0 {
-       clocks = <&scmi_dvfs 1>;
+       power-domains = <&scmi_perf x>;
+       power-domain-names = "perf";
 };

We can, but I retained it so that the clocks property support can be still
validated until it is removed. I think there are few downstream users of
it. It is not just the DTS files you need to look at when dealing with
such things. It is the bindings that matter. Until bindings are not
deprecated and made obsolete, support must exist even if you modify the
only user in the upstream DT.

--
Regards,
Sudeep