On Wednesday 25 January 2012 19:02:45 Marek Vasut wrote:
This patch adapts the bootm command so that it can use an existing atags command set up by a previous bootloader.
Why do you need it?
Default Nokia kernel has patches which using non-standard atags for reporting bootmode, bootreason, hw-rev, NOLO version, boot count, ...
Closed-source Maemo application need to know these properties (read via /proc/bootreason, ...) and will restart device if there is error.
So U-Boot must can reuse old atags from NOLO and tell it new kernel.
If the environment variable "atagaddr" is unset, bootm behaves as normal. If "atagaddr" is set, bootm will use atags address from environment variable and also append new boot args (if specified in u-boot). For example, if a previous boot loader already set up the atags struct at 0x80000100:
setenv atagaddr 0x80000100; bootm 0x80008000
Can't you set those atags correctly in uboot?
No, because atags are not static (e.g bootreason).