[PATCH v2] RFC: ARM: cache-l2x0: update workaround for PL310 errata 727915

[Will Deacon]

On Tue, May 22, 2012 at 07:36:23PM +0100, Colin Cross wrote:
> I was using an omap 4430, triggering l2x0_clean_all from a GPU ioctl
> by calling outer_clean_range(0, ULONG_MAX).  The problem was very
> reproducible at the time, and using the persistent_trace code I posted
> a while back I was able to narrow it down to hanging the cpu (not an
> infinite loop) inside cache_wait_way.  It was 100% reproducible just
> booting a development version of Android, but not if I called
> l2x0_clean_all during boot, so it may depend on cache state or load.

Right, ok. This is definitely a different problem though. Firstly, r3p1 is
not affected by the original erratum and secondly the symptoms do not
include deadlock. The clean during boot also sounds highly suspicious -- is
there a chance you boot the kernel with a dirty L2? Is the L2 enabled or
disabled when entering the kernel [I think u8500 has it enabled]?

Will