From b7c591769b517cdadc24cd7dcdfecdf42a84532e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= <arve@android.com>
Date: Wed, 23 Feb 2011 16:51:58 -0800
Subject: [PATCH] ARM: etm: Power down etm(s) when tracing is not enabled
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Without this change a saw an 18% increase in idle power consumption
on one deivce when trace support is compiled into the kernel. Now
I see the same increase only when tracing.
Change-Id: I21bb5ecf1b7d29ce3790ceeb5323409cc22d5a3b
Signed-off-by: Arve Hjønnevåg <arve@android.com>
---
arch/arm/kernel/etm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
index c37407cf48dd..9548b35c2209 100644
--- a/arch/arm/kernel/etm.c
+++ b/arch/arm/kernel/etm.c
@@ -199,7 +199,7 @@ static int trace_stop_etm(struct tracectx *t, int id)
etm_unlock(t, id);
- etm_writel(t, id, 0x440, ETMR_CTRL);
+ etm_writel(t, id, 0x441, ETMR_CTRL);
while (!(etm_readl(t, id, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
;
if (!timeout) {
@@ -737,7 +737,7 @@ static int __init etm_probe(struct amba_device *dev, struct amba_id *id)
(void)etm_readl(&tracer, t->etm_regs_count, ETMMR_OSSRR);
t->ncmppairs = etm_readl(t, t->etm_regs_count, ETMR_CONFCODE) & 0xf;
- etm_writel(t, t->etm_regs_count, 0x440, ETMR_CTRL);
+ etm_writel(t, t->etm_regs_count, 0x441, ETMR_CTRL);
etm_writel(t, t->etm_regs_count, new_count, ETMR_TRACEIDR);
etm_lock(t, t->etm_regs_count);
--
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