[RFC] clk: meson: t7: Intermittent boot instability and memory corruption on VIM4

[Lucas Tanure <tanure@linux.com>]

Hi,

While testing mainline Linux on the Khadas VIM4 (Amlogic A311D2 / T7), I 
am hitting intermittent system instability, storage loss, and memory 
corruption during boot, unless I append clk_ignore_unused to the kernel 
command line.

Because the failure is intermittent, I am running 100-reboot test 
campaigns to bisect the remaining clocks and isolate which clocks are 
critical and cannot be safely disabled.

As testing takes significant time over serial console, I wanted to check 
if Amlogic or the maintainers could shed light on this:

Are there specific T7 clocks or hardware domains that must remain 
critical/protected even without an explicit in-kernel consumer?

Current clocks being disabled that don't kill the board on a test run:

[    0.380313] clk: Disabling unused clocks
[    0.380413] clk: Disabled unused clock: rtc_dualdiv
[    0.380718] clk: Disabled unused clock: rtc_duandiv_in
[    0.381377] clk: Unprepared unused clock: a73_div16
[    0.381972] clk: Unprepared unused clock: cpu_div16
[    0.382605] clk: Unprepared unused clock: f50m
[    0.383174] clk: Unprepared unused clock: fixed_pll_dco
[    0.383786] clk: Unprepared unused clock: hdmi_pll_osc
[    0.384416] clk: Unprepared unused clock: sys1_pll_osc
[    0.385056] clk: Unprepared unused clock: earc_osc
[    0.385652] clk: Unprepared unused clock: pcie_refclk_osc
[    0.386323] clk: Unprepared unused clock: eth_pll_osc
[    0.386961] clk: Unprepared unused clock: pcie_osc
[    0.387548] clk: Unprepared unused clock: mclk_pll_osc
[    0.388187] clk: Unprepared unused clock: usb_pll1_osc
[    0.388826] clk: Unprepared unused clock: usb_pll0_osc
[    0.389465] clk: Unprepared unused clock: tcon_pll_osc
[    0.390105] clk: Unprepared unused clock: top_pll_osc
[    0.390738] clk: Unprepared unused clock: aud_pll_osc
[    0.391361] clk: Unprepared unused clock: ddr_pll_osc

I am not forcing any clock to be disabled; I am forcing all clocks to 
stay on and letting them be disabled if unused one by one.

Any guidance or hints on required platform clocks would be greatly 
appreciated.

Thanks,
Lucas Tanure

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