From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946034Ab3FUUbg (ORCPT ); Fri, 21 Jun 2013 16:31:36 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:60766 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945951Ab3FUUbf (ORCPT ); Fri, 21 Jun 2013 16:31:35 -0400 From: Rohit Vaswani To: Marc Zyngier , John Stultz , Thomas Gleixner Cc: Rohit Vaswani , Rob Herring , Russell King , Stephen Boyd , linux-kernel@vger.kernel.org Subject: [PATCH] ARM: arch timer: Set the TVAL before timer is enabled Date: Fri, 21 Jun 2013 13:31:24 -0700 Message-Id: <1371846684-23730-1-git-send-email-rvaswani@codeaurora.org> X-Mailer: git-send-email 1.7.8.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On some hardware, the timer deasserts the interrupt when a new TVAL is written only when the enable bit is cleared. Hence explicitly disable the timer and then program the TVAL followed by enabling the timer. If this order is not followed, there are chances that you would not receive any timer interrupts. This is done as suggested in https://lkml.org/lkml/2012/8/11/39 Signed-off-by: Rohit Vaswani --- drivers/clocksource/arm_arch_timer.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index a2b2541..05ba0c2 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -103,9 +103,10 @@ static inline void set_next_event(const int access, unsigned long evt) { unsigned long ctrl; ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL); - ctrl |= ARCH_TIMER_CTRL_ENABLE; - ctrl &= ~ARCH_TIMER_CTRL_IT_MASK; + ctrl &= ~(ARCH_TIMER_CTRL_ENABLE | ARCH_TIMER_CTRL_IT_MASK); + arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl); arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt); + ctrl |= ARCH_TIMER_CTRL_ENABLE; arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl); } -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation