Re: [PATCH V3 0/2] clk: imx: introduce fsl,always-on-clocks

From: Peng Fan
Date: Tue Sep 13 2022 - 08:16:13 EST




On 9/13/2022 6:29 PM, Marco Felsch wrote:
Hi Peng,

On 22-09-13, Peng Fan (OSS) wrote:
From: Peng Fan <peng.fan@xxxxxxx>

V3:
Rename to fsl,always-on-clocks

V2:
Use protected-clocks
https://lore.kernel.org/all/20220816130327.2987710-1-peng.fan@xxxxxxxxxxx/

V1:
Use fsl,protected-clocks
https://lore.kernel.org/all/20220815033632.1687854-1-peng.fan@xxxxxxxxxxx/

There are two cases that I wanna this property could serve:
Virtualization: root cell linux run in parallel with inmate cell
AMP: M7/4 runs in parallel with A53

The major case is:
Jailhouse hypervisor only support partition, so devices are partitioned.
But there is only CCM module that provides clock, the CCM is handled by
root cell linux, need make sure the root cell linux not shutdown the
clocks using by inmate cell.

I was thinking whether need to provide a rate entry to ask root cell
configure the clk rate for inmate cell. But NXP downstream not have it,
see https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/clk/imx/clk-imx8mp.c?h=lf-5.15.y#n690
So just leave the property as uint32-array.

Can you please check my recent proposal? I recently stumbled over such
an issue on the mx8mm-evk as well but with the 32k clock provided by the
pmic. Unfortunately I forgot to add you to the to list, I will change
that. If that proposal will fix your problem, I would like to go the
generic way.

I vote for a generic solution.

Thanks,
Peng.


https://patchwork.kernel.org/project/linux-clk/list/?series=676522

Regards,
Marco



This patchset could also benifit AMP case, check the two commits
commit 19565ea12d61 ("clk: imx: add mcore_booted module paratemter")
commit d097cc045b64 ("clk: imx8mp: remove SYS PLL 1/2 clock gates")
Although I not plan to drop the upper two patches, this patchset
exposes opportunity for better power consumption.

Peng Fan (2):
dt-bindings: clock: imx8m/imx93: introduce fsl,always-on-clocks
property
clk: imx: support fsl,always-on-clocks

.../bindings/clock/imx8m-clock.yaml | 4 ++++
.../bindings/clock/imx93-clock.yaml | 4 ++++
drivers/clk/imx/clk-imx8mm.c | 2 ++
drivers/clk/imx/clk-imx8mn.c | 2 ++
drivers/clk/imx/clk-imx8mp.c | 2 ++
drivers/clk/imx/clk-imx8mq.c | 2 ++
drivers/clk/imx/clk.c | 21 +++++++++++++++++++
drivers/clk/imx/clk.h | 2 ++
8 files changed, 39 insertions(+)

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2.37.1