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Commit 988257cf authored by Alexander Shishkin's avatar Alexander Shishkin Committed by Russell King
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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: default avatarAlexander Shishkin <virtuoso@slind.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 9e354ea8

arch/arm/kernel/etm.c

+3 −1
Original line number Diff line number Diff line
@@ -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);