From patchwork Fri Mar 28 17:31:47 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 3905451 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id B49D7BF540 for ; Fri, 28 Mar 2014 17:31:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D924F202FE for ; Fri, 28 Mar 2014 17:31:25 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C999720212 for ; Fri, 28 Mar 2014 17:31:23 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WTace-0001iy-Ab; Fri, 28 Mar 2014 17:31:16 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WTacb-0006H7-Mp; Fri, 28 Mar 2014 17:31:13 +0000 Received: from mail.linuxfoundation.org ([140.211.169.12]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WTacY-0006FY-B4 for linux-arm-kernel@lists.infradead.org; Fri, 28 Mar 2014 17:31:11 +0000 Received: from localhost (unknown [12.232.193.53]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 7CDAA9F4; Fri, 28 Mar 2014 17:30:53 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Subject: [PATCH 3.13 03/46] clocksource: vf_pit_timer: use complement for sched_clock reading Date: Fri, 28 Mar 2014 10:31:47 -0700 Message-Id: <20140328173135.096192258@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140328173134.630198216@linuxfoundation.org> References: <20140328173134.630198216@linuxfoundation.org> User-Agent: quilt/0.60-1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140328_133110_470130_A33C3003 X-CRM114-Status: GOOD ( 11.19 ) X-Spam-Score: -2.3 (--) Cc: linux@arm.linux.org.uk, Greg Kroah-Hartman , daniel.lezcano@linaro.org, Stefan Agner , stable@vger.kernel.org, Thomas Gleixner , Shawn Guo , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 3.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefan Agner commit 224aa3ed45c8735ae02bb2ecca002409fa6aa772 upstream. Vybrids PIT register is monitonic decreasing. However, sched_clock reading needs to be monitonic increasing. Use bitwise not to get the complement of the clock register. This fixes the clock going backward. Also, the clock now starts at 0 since we load the register with the maximum value at start. Signed-off-by: Stefan Agner Acked-by: Shawn Guo Cc: daniel.lezcano@linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux@arm.linux.org.uk Link: http://lkml.kernel.org/r/d25af915993aec1b486be653eb86f748ddef54fe.1394057313.git.stefan@agner.ch Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- drivers/clocksource/vf_pit_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/clocksource/vf_pit_timer.c +++ b/drivers/clocksource/vf_pit_timer.c @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(v static u64 pit_read_sched_clock(void) { - return __raw_readl(clksrc_base + PITCVAL); + return ~__raw_readl(clksrc_base + PITCVAL); } static int __init pit_clocksource_init(unsigned long rate)