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authorTodd Poynor <toddpoynor@google.com>2011-02-15 11:48:42 -0800
committerTodd Poynor <toddpoynor@google.com>2011-02-22 20:01:45 -0800
commit91406b03fa4add49db13e55c3220911be55d9883 (patch)
treea1cff9f0818e7f039bc575d9ef4abc452292f966 /arch/arm/mm
parent70ee83c5d185b6ac1026b8e6e5e31616ebe39320 (diff)
ARM: Cortex-A9: Enable dynamic clock gating
Enable dynamic high level clock gating for Cortex-A9 CPUs, as described in 2.3.3 "Dynamic high level clock gating" of the Cortex-A9 TRM. This may cut the clock of the integer core, system control block, and Data Engine in certain conditions. Add ARM errata 720791 to avoid corrupting the Jazelle instruction stream on earlier Cortex-A9 revisions. Change-Id: I48e51d907e593f26982ea91b0a811553f68e3c86 Signed-off-by: Todd Poynor <toddpoynor@google.com>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r--arch/arm/mm/proc-v7.S10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 197f21bed5e9..f5e22615a1fe 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -238,6 +238,16 @@ __v7_setup:
2: ldr r10, =0x00000c09 @ Cortex-A9 primary part number
teq r0, r10
bne 3f
+ cmp r6, #0x10 @ power ctrl reg added r1p0
+ mrcge p15, 0, r10, c15, c0, 0 @ read power control register
+ orrge r10, r10, #1 @ enable dynamic clock gating
+ mcrge p15, 0, r10, c15, c0, 0 @ write power control register
+#ifdef CONFIG_ARM_ERRATA_720791
+ teq r5, #0x00100000 @ only present in r1p*
+ mrceq p15, 0, r10, c15, c0, 2 @ read "chicken power ctrl" reg
+ orreq r10, r10, #0x30 @ disable core clk gate on
+ mcreq p15, 0, r10, c15, c0, 2 @ instr-side waits
+#endif
#ifdef CONFIG_ARM_ERRATA_742230
cmp r6, #0x22 @ only present up to r2p2
mrcle p15, 0, r10, c15, c0, 1 @ read diagnostic register