Re: [PATCH v2] clk: meson-gxbb: set fclk_div3 as CLK_IS_CRITICAL

From: Stephen Boyd
Date: Tue Nov 06 2018 - 13:43:25 EST


Quoting Jerome Brunet (2018-11-05 15:08:20)
> From: Christian Hewitt <christianshewitt@xxxxxxxxx>
>
> On the Khadas VIM2 (GXM) and LePotato (GXL) board there are problems
> with reboot; e.g. a ~60 second delay between issuing reboot and the
> board power cycling (and in some OS configurations reboot will fail
> and require manual power cycling).
>
> Similar to 'commit c987ac6f1f088663b6dad39281071aeb31d450a8 ("clk:
> meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL")' the SCPI Cortex-M4
> Co-Processor seems to depend on FCLK_DIV3 being operational.
>
> Until commit 05f814402d6174369b3b29832cbb5eb5ed287059 ("clk:
> meson: add fdiv clock gates"), this clock was modeled and left on by
> the bootloader.
>
> We don't have precise documentation about the SCPI Co-Processor and
> its clock requirement so we are learning things the hard way.
>
> Marking this clock as critical solves the problem but it should not
> be viewed as final solution. Ideally, the SCPI driver should claim
> these clocks. We also depends on some clock hand-off mechanism
> making its way to CCF, to make sure the clock stays on between its
> registration and the SCPI driver probe.
>
> Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
> Signed-off-by: Christian Hewitt <christianshewitt@xxxxxxxxx>
> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
> ---

I can toss this into clk-fixes?