From patchwork Wed Mar 5 22:11:08 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Agner X-Patchwork-Id: 3779771 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 73DAB9F383 for ; Wed, 5 Mar 2014 22:12:07 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id AC92E2024C for ; Wed, 5 Mar 2014 22:12:06 +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 C68B720225 for ; Wed, 5 Mar 2014 22:12:05 +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 1WLK2i-0002dW-CQ; Wed, 05 Mar 2014 22:12:00 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WLK2f-0002PL-MZ; Wed, 05 Mar 2014 22:11:57 +0000 Received: from mail.kmu-office.ch ([178.209.48.102]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WLK2c-0002Nn-9x for linux-arm-kernel@lists.infradead.org; Wed, 05 Mar 2014 22:11:55 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.kmu-office.ch (Postfix) with ESMTP id 912E44467F6 for ; Wed, 5 Mar 2014 23:08:33 +0100 (CET) X-Virus-Scanned: by amavisd-new at kmu-office.ch Received: from mail.kmu-office.ch ([127.0.0.1]) by localhost (mail.kmu-office.ch [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id W4mewTtXXZWC for ; Wed, 5 Mar 2014 23:08:33 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by mail.kmu-office.ch (Postfix) with ESMTP id 4FD02446805 for ; Wed, 5 Mar 2014 23:08:33 +0100 (CET) Received: from luegisland.agner.local (195-226-23-140.pool.cyberlink.ch [195.226.23.140]) (Authenticated sender: stefan@agner.ch) by mail.kmu-office.ch (Postfix) with ESMTPSA id E549D4467F5; Wed, 5 Mar 2014 23:08:32 +0100 (CET) From: Stefan Agner To: daniel.lezcano@linaro.org, tglx@linutronix.de, shawn.guo@linaro.org, linux@arm.linux.org.uk Subject: [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading Date: Wed, 5 Mar 2014 23:11:08 +0100 Message-Id: X-Mailer: git-send-email 1.9.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140305_171154_471452_7B5B5B49 X-CRM114-Status: GOOD ( 10.25 ) X-Spam-Score: -1.9 (-) Cc: Stefan Agner , linux-kernel@vger.kernel.org, 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=-4.2 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 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 --- drivers/clocksource/vf_pit_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c index 02821b0..a918bc4 100644 --- a/drivers/clocksource/vf_pit_timer.c +++ b/drivers/clocksource/vf_pit_timer.c @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) 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)