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authorCatalin Marinas <catalin.marinas@arm.com>2008-11-10 14:14:11 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2008-11-10 14:14:11 +0000
commit8553cb67d2318db327071018fc81084cbabccc46 (patch)
treef2db64a188cbf2cce745720bf3d279daa2768609 /arch
parent73b63efaac7352c9e2bf1570fac98fd44a99f8f9 (diff)
Modern processors may need to drain the WB before WFI
Since WFI may cause the processor to enter a low-power mode, data may still be in the write buffer. This patch adds a DSB (or DWB) to the cpu_(v6|v7)_do_idle functions before the WFI. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/mm/proc-v6.S2
-rw-r--r--arch/arm/mm/proc-v7.S1
2 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 294943b8597..f0cc599facb 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -71,6 +71,8 @@ ENTRY(cpu_v6_reset)
* IRQs are already disabled.
*/
ENTRY(cpu_v6_do_idle)
+ mov r1, #0
+ mcr p15, 0, r1, c7, c10, 4 @ DWB - WFI may enter a low-power mode
mcr p15, 0, r1, c7, c0, 4 @ wait for interrupt
mov pc, lr
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 721b7d53bfd..0e11d9716a7 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -63,6 +63,7 @@ ENDPROC(cpu_v7_reset)
* IRQs are already disabled.
*/
ENTRY(cpu_v7_do_idle)
+ dsb @ WFI may enter a low-power mode
wfi
mov pc, lr
ENDPROC(cpu_v7_do_idle)