Hi Benjamin,

Am Dienstag, dem 14.09.2021 um 17:46 +0200 schrieb Benjamin Gaignard:

Le 10/09/2021 à 22:26, Lucas Stach a écrit :

quoted

This adds a driver for the blk-ctrl blocks found in the i.MX8M* line of
SoCs. The blk-ctrl is a top-level peripheral located in the various *MIX
power domains and interacts with the GPC power controller to provide the
peripherals in the power domain access to the NoC and ensures that those
peripherals are properly reset when their respective power domain is
brought back to life.

Software needs to do different things to make the bus handshake happen
after the GPC *MIX domain is powered up and before it is powered down.
As the requirements are quite different between the various blk-ctrls
there is a callback function provided to hook in the proper sequence.

The peripheral domains are quite uniform, they handle the soft clock
enables and resets in the blk-ctrl address space and sequencing with the
upstream GPC power domains.

Hi Lucas,

I have tried to use your patches for IMX8MQ but it seems that the hardware
have different architecture.
On IMX8MQ there is only one VPU domain for G1 and G2 and that doesn't match
with your implementation where it is needed to have "bus" and devices power domain.
 From what I experiment in current IMX8MQ implementation of blk-ctrl (inside VPU driver)
enabling the 3 clocks (bus, G1, G2) is needed to reset the VPUs.

Do you think you can update your design to take care of these hardware variations ?

The clocking/reset of the blk-ctrl and ADB in the i.MX8MQ VPU power
domain is really a bit strange, as the ADB reset is tied to the VPU
resets and the clk-ctrl seem to require all 3 VPU clocks, instead of
only the bus clock as in newer designs. However I was able to make it
work with the existing blk-ctrl driver design.

My current WIP patches (only tested with the G1 core so far) on top of
the v5 of the series I just sent out can be found here:
https://git.pengutronix.de/cgit/lst/linux/log/?h=imx8mq-vpu-blk-ctrl

Hope this helps.

Regards,
Lucas