From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753898Ab3CODbo (ORCPT ); Thu, 14 Mar 2013 23:31:44 -0400 Received: from wolverine02.qualcomm.com ([199.106.114.251]:4325 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753689Ab3CODbl (ORCPT ); Thu, 14 Mar 2013 23:31:41 -0400 X-IronPort-AV: E=Sophos;i="4.84,849,1355126400"; d="scan'208";a="29880100" From: Stephen Boyd To: David Brown , Daniel Walker , Bryan Huntsman Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/3] ARM: msm: Stop counting before reprogramming clockevent Date: Thu, 14 Mar 2013 20:31:37 -0700 Message-Id: <1363318299-10814-2-git-send-email-sboyd@codeaurora.org> X-Mailer: git-send-email 1.8.2.rc2.4.g7799588 In-Reply-To: <1363318299-10814-1-git-send-email-sboyd@codeaurora.org> References: <1363318299-10814-1-git-send-email-sboyd@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the clockevent is forcibly reprogrammed to have a different match value we mistakenly assume the timer is not ticking and program a new match value while the timer is running. Although we clear the timer before programming a new match, it's better to stop the timer before clearing it so that we're sure the proper amount of ticks are counted. Failure to do so can lead to missed ticks and system hangs. Signed-off-by: Stephen Boyd --- arch/arm/mach-msm/timer.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c index 2969027..f9fd77e 100644 --- a/arch/arm/mach-msm/timer.c +++ b/arch/arm/mach-msm/timer.c @@ -62,7 +62,10 @@ static int msm_timer_set_next_event(unsigned long cycles, { u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE); - writel_relaxed(0, event_base + TIMER_CLEAR); + ctrl &= ~TIMER_ENABLE_EN; + writel_relaxed(ctrl, event_base + TIMER_ENABLE); + + writel_relaxed(ctrl, event_base + TIMER_CLEAR); writel_relaxed(cycles, event_base + TIMER_MATCH_VAL); writel_relaxed(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE); return 0; -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation