Hi York,
On Mon, 18 Aug 2014 19:14:07 -0700 York Sun yorksun@freescale.com wrote:
On 08/16/2014 11:16 PM, Masahiro Yamada wrote:
I have been in trouble for a while to debug some nasty problem where neighter a debugger nor printf() function is available.
I found the lowlevel debug feature in ARM Linux can be used as is in U-Boot too.
I tested this series on our SoCs (32bit ARM, specificly Coretex-A9). Because I was not sure about aarch64, I have this feature depend on "! ARM64".
1/4 and 2/4 refactor a bit and move CONFIG_ARM64 to Kconfig.
3/4 imports some source files from Linux 3.16 and 4/4 adds the Kconfig menu.
Dear Masahiro,
How do you use this debug facility? Do you print to memory?
I don't know enough to comment on the patch. I don't see CP15 co-process in the SoC I am debugging.
At least one UART device must be available to use this facility.
The UART should be initialized (setup appropriate baudrate etc.) in the early boot stage of U-Boot (= generally lowlevel_init() func) or in another boot loader if U-Boot is loaded by it.
Best Regards Masahiro Yamada