[PATCH v2 2/4] zynq: move static peripheral mappings

On 2012-10-23 15:53 -0500, Josh Cartwright wrote:

On Tue, Oct 23, 2012 at 03:09:23PM -0500, Rob Herring wrote:

quoted

On 10/23/2012 09:50 AM, Arnd Bergmann wrote:

quoted

On Monday 22 October 2012, Josh Cartwright wrote:

quoted

-#define SCU_PERIPH_PHYS			0xF8F00000
-#define SCU_PERIPH_VIRT			SCU_PERIPH_PHYS
+#define SCU_PERIPH_PHYS		0xF8F00000
+#define SCU_PERIPH_SIZE		SZ_8K
+#define SCU_PERIPH_VIRT		(PL310_L2CC_VIRT - SCU_PERIPH_SIZE)

And your patch 3 already obsoletes this mapping.

Actually, it's probably still needed. The smp platform code typically
reads the number of cores from the SCU and the mapping has to be in
place before ioremap is up. I don't think there is an architected way to
get the number of cores, but it would be nice to avoid this early SCU
access. We could also mandate getting the core count from DT instead.

Also, the physical address can be read with this on A9's:

        asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));

For the sake of the zynq cleanups, I think it may still make sense to
remove the SCU peripheral mappings for now.  By the time we're ready to
push in SMP support for zynq, maybe we can tackle the problem of how to
solve the SCU mapping problem generically.

Then the static mapping can be removed if and when the we "solve the SCU
mapping problem generically".  There's no point in removing it until
then since it doesn't cause any actual problems, does it?

Cheers,
-- 
Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)