AM3352: Control GPIO during Linux Kernel decompression

Part Number: AM3352

Hi,

linux-4.19.38

u-boot-2018.01

I am using custom board (referenced from evm-sk), everything works fine.

The question is,

I am using external watchdog, which is connected to a GPIO pin for feed dog. The watchdog IC requires feed dong every seconds. (<= 0.9s)

However, I found that during kernel decompression, there is an interval more than 2 seconds. During the interval I can't feed dog, thus, the system is reset.

We are using lzma compression. so I am wondering if I can patch code in lib/decompress_unlzma.c to control GPIO, or there are other solutions for my scenario?

I've tried to use __raw_writel to set the registers of GPIO Set/Clr/DataOut, but it may cause error. (My board won't boot if I add __raw_writel / __raw_readl in unlzma())

Thank you!

Sincerely,
Howard