From 8553cb67d2318db327071018fc81084cbabccc46 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Mon, 10 Nov 2008 14:14:11 +0000 Subject: 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 --- arch/arm/mm/proc-v6.S | 2 ++ arch/arm/mm/proc-v7.S | 1 + 2 files changed, 3 insertions(+) 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) -- cgit v1.2.3