linux-kernel - [PATCH 9/9 (originally 8)] ARM: etm: Power down etm(s) when tracing is not enabled

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Date:	Wed, 23 Feb 2011 17:36:09 -0800
From:	Arve Hjønnevåg <arve@...roid.com>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	linux-omap@...r.kernel.org,
	Arve Hjønnevåg <arve@...roid.com>,
	Russell King <linux@....linux.org.uk>,
	Alexander Shishkin <virtuoso@...nd.org>,
	Jason Wessel <jason.wessel@...driver.com>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 9/9 (originally 8)] ARM: etm: Power down etm(s) when tracing is not enabled

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.

Signed-off-by: Arve Hjønnevåg <arve@...roid.com>
---
 arch/arm/kernel/etm.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
index 48de5a4..f2bc95e 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) {
@@ -738,7 +738,7 @@ 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);
 
-- 
1.7.3.1

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