On Thu, Jul 31, 2014 at 03:24:17PM +0100, S?ren Brinkmann wrote:

Hi all,

similar to the patch enabling the SCU standby mode
(https://lkml.org/lkml/2014/7/30/122), I have a patch to enable the A9's
'dynamic clock gating'
(http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/CIHBGEHE.html)
in platform code. This might also be a candidate to enable in common
code.
Do you think that would make sense?
I tried to find the right place to add this and was looking at
mm/proc-v7.S. It probably works to put it there, but does not really
seem to be the right place.

As reference, this is what I currently have as part of platform code:
  /* A9 clock gating */
  asm volatile ("mrc  p15, 0, r12, c15, c0, 0\n"
                "orr  r12, r12, #1\n"
                "mcr  p15, 0, r12, c15, c0, 0\n"
                : /* no outputs */
                : /* no inputs */
                : "r12");

This should *really* be done by firmware.

Will