From 988257cfcbc468cb26b3addfcab1d0187c4e2399 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Wed, 4 Aug 2010 11:27:33 +0100 Subject: [PATCH] ARM: 6294/1: etm: do a dummy read from OSSRR during initialization The first read from ETM OS save and restore register after the power down bit deassertion returns garbage. Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Alexander Shishkin Signed-off-by: Russell King --- arch/arm/kernel/etm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c index 9e9db63..56418f9 100644 --- a/arch/arm/kernel/etm.c +++ b/arch/arm/kernel/etm.c @@ -543,7 +543,9 @@ static int __init etm_probe(struct amba_device *dev, struct amba_id *id) t->etm_portsz = 1; etm_unlock(t); - ret = etm_readl(t, ETMMR_PDSR); + (void)etm_readl(t, ETMMR_PDSR); + /* dummy first read */ + (void)etm_readl(&tracer, ETMMR_OSSRR); t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf; etm_writel(t, 0x440, ETMR_CTRL); -- 2.7.4