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

[Dennis Gilmore]

On Thu, 01 Aug 2013 10:53:49 +0200
Stefano Babic <sbabic at denx.de> wrote:

> 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. ;)

ultimately I want to have a standard way to boot any system that just
works and does not need the installer to know or care what the target
system is. using boot.scr and uEnv.txt does not work for my goals.

> > 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

ultimately for Fedora we do not want to use uEnv.txt or boot.scr at all
we want to use a extlinux.conf file and sysboot provided by cmd_pxe the
rest is to provide flexibility and options to users to choose different
ways to boot. the above is not at all suitable. 

> 
> 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
> 
>