Hi Anshul,
On Tuesday, 3 June 2025 at 16:24:40 Anshul Dalal <ansh...@ti.com> wrote:
> This patch set adds support for falcon boot on AM62a, 62p and 62x by
> bypassing A53 SPL and U-boot.
>
> Existing Boot flow:
> R5 SPL -> ATF -> A53 SPL -> U-Boot -> Linux Kernel
>
> Updated flow:
> R5 SPL -> ATF -> Linux Kernel
>
> ...
I tried this series on a custom device based on AM62P. While it's working
mostly fine, I noticed that PWM0 is not working after a falcon boot from
R5F, while it was working correctly after a boot through full U-Boot.
After a bit of debugging, I noticed that the epwm_tbclk0 is marked as
disabled in hardware in debugfs's clk_summary even if enabled by software:
$ head -n 2 /sys/kernel/debug/clk/clk_summary && cat
/sys/kernel/debug/clk/clk_summary | grep pwm
enable prepare protect
duty hardware connection
clock count count count rate
accuracy phase cycle enable consumer id
clk:86:0 0 0 0 250000000 0
0 50000 Y 23000000.pwm fck
epwm_tbclk2 0 0 0 0 0
0 50000 N deviceless no_connection_id
epwm_tbclk1 0 0 0 0 0
0 50000 N deviceless no_connection_id
epwm_tbclk0 1 1 0 0 0
0 50000 N 23000000.pwm tbclk
Reading the associated register (0x00104130) returns in fact 0x00000000,
while writing to it has no effect (and after a write the register reads
back as 0x00000000).
Do you have any idea on the reason of this behaviour? I don't think it is
directly related to the Falcon boot implementation, but probably a side
effect of it (maybe something that was enabled by A53 SPL?).
Thank you very much for the very valuable work!
Kind regards,
Francesco
