[U-Boot] [PATCH 1/2 V3] arm926: Flush the data cache before disabling it

Sughosh Ganu urwithsughosh at gmail.com
Sat Jan 14 10:21:34 CET 2012


hi Albert,

On Sat Jan 14, 2012 at 10:02:16AM +0100, Albert ARIBAUD wrote:

<snip>

> >  	/*
> >-	 * disable MMU stuff and caches
> >+	 * disable MMU and D cache, and enable I cache.
> >  	 */
> >  	mrc	p15, 0, r0, c1, c0, 0
> >-	bic	r0, r0, #0x00002300	/* clear bits 13, 9:8 (--V- --RS) */
> >+	bic	r0, r0, #0x00000300	/* clear bits 9:8 ( --RS) */
> 
> NAK--this alters the functioning of U-Boot for many boards in ways
> unpredictable. If you want to get this specific V change into ARM,
> then please also add code to set V in all relevant SoCs, or (better
> yet IMO) make "do not set V in cpu_init_crit" a config option and
> set it in the relevant SoCs or boards.

  Ok, but the problem i have is that i don't have visibility into all
  the SoC's out there -- don't know what maps where. So i think it
  should be done by people using those specific SOC's. I can add a
  config option, and introduce it for my board/SOC. Will that be fine.

  In any case, i will split this patch into two, with the cache
  flushing part kept separate, as it fixes a real issue on my
  board. Will work out the setting of the V bit in a separate patch.

-sughosh


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