[U-Boot-Users] [PATCH] fdt: add fdtcmd env var to allow post processing of device tree before boot

[Kumar Gala]

On Aug 4, 2008, at 1:56 PM, Wolfgang Denk wrote:

> In message <Pine.LNX.4.64.0808041346350.3885 at blarg.am.freescale.net>  
> you wrote:
>> Added the 'fdtcmd' environment variable as a way to provide 'fdt'  
>> commands
>> that the user can supply to manipulate the device tree after  
>> ft_board_setup()
>> and before the tree is handled to the kernel.
>
> Where exactly is the needed, i. e. which spoecific situation  do  you
> have  in  mind  where  this function cannot be implemented as part of
> either a "preboot" or a standard "bootcmd" command sequence?

The situation is if we are fixing up or adding properties or nodes via  
the ft_board_setup() how do I go about modifying that before the  
device tree is handed to the kernel.

An example would be if we start adding the i2c node via code in u-boot  
and after we have done that we want to add a frequency property at  
runtime w/o changing the u-boot code.

- k