[U-Boot] [PATCH 02/14] arm: Optionally use existing atags in bootm.c

Marek Vasut
2012-01-25T20:55:53Z

> 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, ...

So what? Make u-boot pass arbitrary atags and specify them in your board file.

>
> Closed-source Maemo application need to know these properties (read via
> /proc/bootreason, ...) and will restart device if there is error.

Fine?
>
> So U-Boot must can reuse old atags from NOLO and tell it new kernel.

must can reuse? Anyway, that's nonsense, why won't u-boot be able to craft those
atags?

>
> > > 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).

So? You craft them properly in u-boot?

M