[U-Boot] [PATCH] wandboard: add pxe support, set default boot command like highbank

[Stefano Babic <sbabic@denx.de>]

Hi Dennis,

On 01/08/2013 01:27, Robert Nelson wrote:

>> kernel_boot=echo Trying kernel...; ${fs}load ${devtype} ${devnum}
>> ${kernel_addr_r} ${prefix}vmlinuz && ${fs}load ${devtype} ${devnum}
>> ${ramdisk_addr_r} ${prefix}initrd.img && bootz ${kernel_addr_r}
>> ${ramdisk_addr_r}:${filesize} ${fdt_addr}
>> script_boot=echo Trying script images...; for script in
>> ${boot_scripts}; do ${fs}load ${devtype} ${devnum} ${script_addr}
>> ${prefix}${script} && echo Executing ${prefix}${script}... && source
>> ${script_addr}; done;
>> env_boot=echo Trying environment file...; ${fs}load ${devtype}
>> ${devnum} ${script_addr} ${prefix}uEnv.txt && Executing
>> ${prefix}uEnv.txt... && env import -t  ${script_addr} ${filesize}};
> 
> Guys, this is just silly.. Your using both uEnv.txt/boot.scr scripts
> by default, which you could use to "hide" all this extra stuff in a
> text file on the boot drive, that way mainline u-boot doesn't have to
> be patched for every little change. ;)
> 
> I know it's bikeshedding, but most boards can be converted to just:
> 
> #define CONFIG_BOOTCOMMAND \
> 	"mmc dev ${mmcdev};" \
> 	"if mmc rescan; then " \
> 		"echo SD/MMC found on device ${mmcdev};" \
> 		"if run loadbootenv; then " \
> 			"run importbootenv;" \
> 		"fi;" \
> 		"if test -n $uenvcmd; then " \
> 			"echo Running uenvcmd ...;" \
> 			"run uenvcmd;" \
> 		"fi;" \
> 		"if run loadsomefailsafedefault; then " \
> 			"run mmcboot;" \
> 		"fi;" \
> 	"fi;"
> #endif
> 

Right - the meaning of CONFIG_EXTRA_ENV_SETTINGS is to have a minimal
default environment, allowing the user to extend it to a full blown
adding whatever he wants. However, in the last times I see that the
meaning is moving to *the environment*. There is something wrong,  also
because, as Robert says, each small change require to patch u-boot. But
then, why do you need the environment at all ?

And the setup is then suitable for a strict range of applications, but
not all.

Regards,
Stefano Babic


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