[PATCH 5/6] omap3: pm: Clear the SCTLR C bit in asm code to prevent data cache allocation

[Santosh Shilimkar]

On the newer ARM processors like CortexA8, CortexA9, the caches can be
speculatively loaded while they are getting flushed.

Clear the SCTLR C bit to prevent further data cache allocation as
part of cache clean routine

Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
Cc: Kevin Hilman <khilman at ti.com>
---
 arch/arm/mach-omap2/sleep34xx.S |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S
index 28baeb2..1e723bb 100644
--- a/arch/arm/mach-omap2/sleep34xx.S
+++ b/arch/arm/mach-omap2/sleep34xx.S
@@ -224,6 +224,12 @@ l1_logic_lost:
 	mrc	p15, 0, r4, c1, c0, 0	@ save control register
 	stmia	r8!, {r4}
 
+	/* Clear the SCTLR C bit to prevent further data cache allocation */
+	mrc	p15, 0, r0, c1, c0, 0
+	bic	r0, r0, #(1 << 2)	@ Disable the C bit
+	mcr	p15, 0, r0, c1, c0, 0
+	isb
+
 clean_caches:
 	/*
 	 * jump out to kernel flush routine
@@ -270,6 +276,12 @@ omap3_do_wfi:
 	nop
 	bl wait_sdrc_ok
 
+	mrc	p15, 0, r0, c1, c0, 0
+	tst	r0, #(1 << 2)		@ Check C bit enabled?
+	orreq	r0, r0, #(1 << 2)	@ Enable the C bit if cleared
+	mcreq	p15, 0, r0, c1, c0, 0
+	isb
+
 /*
  * ===================================
  * == Exit point from non-OFF modes ==
-- 
1.6.0.4