[U-Boot] [PATCH] ppc: Unlock cache-as-ram in a consistent manner

Wolfgang Denk wd at denx.de
Tue Jul 21 00:16:57 CEST 2009


Dear "Liu Dave-R63238",

In message <D7CCA83BB0796C49BC0BB53B6AB120895152B9 at zch01exm21.fsl.freescale.net> you wrote:
> > Previously, non-e500 architectures only unlocked their data 
> > cache which
> > was used as early RAM when booting to Linux using the "bootm" command.
> > This change causes all PPC boards with 
> > CONFIG_SYS_INIT_RAM_LOCK defined
> > to unlock their data cache during U-Boot's initialization.  This
> > improves U-Boot performance and provides a common cache state when
> > booting to different OSes.
> > 
> > Signed-off-by: Peter Tyser <ptyser at xes-inc.com>
> > ---
> > I've tested this on 86xx boards, it'd be great if someone 
> > could test on
> > 83xx and 74xx/7xx.  85xx boards should not be affected by this change.
> > 
> > This change assumes 
> > http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/63423
> > has already been applied, or the lib/ppc patches in the diffs 
> > below can
> > be changed to lib_ppc.
> 
> I'm afraid some 83xx boards will not work after the patch is applied.
> It is some was assuming the data cache locked. (that is cache-inhibited)

Are you just concerned, or did you actually test the patch, with
negative results?

Best regards,

Wolfgang Denk

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