From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752960AbaCFDSg (ORCPT ); Wed, 5 Mar 2014 22:18:36 -0500 Received: from mail-bl2lp0208.outbound.protection.outlook.com ([207.46.163.208]:34695 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752185AbaCFDSf (ORCPT ); Wed, 5 Mar 2014 22:18:35 -0500 From: Jingchang Lu To: Shawn Guo , Stefan Agner CC: "daniel.lezcano@linaro.org" , "tglx@linutronix.de" , "linux@arm.linux.org.uk" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading Thread-Topic: [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading Thread-Index: AQHPON3HUpK7HJWWQ0yawbcrDHe6WprTYsKA Date: Thu, 6 Mar 2014 03:18:14 +0000 Message-ID: References: <20140306014530.GA11366@S2101-09.ap.freescale.net> In-Reply-To: <20140306014530.GA11366@S2101-09.ap.freescale.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [123.151.195.49] x-forefront-prvs: 0142F22657 x-forefront-antispam-report: SFV:NSPM;SFS:(10009001)(6009001)(428001)(13464003)(199002)(189002)(377454003)(24454002)(51704005)(77982001)(74876001)(63696002)(54356001)(76576001)(93516002)(56816005)(76482001)(33646001)(53806001)(79102001)(74706001)(46102001)(66066001)(65816001)(59766001)(69226001)(95666003)(86362001)(90146001)(76786001)(51856001)(54316002)(81342001)(81542001)(94946001)(19580395003)(4396001)(87266001)(2656002)(83322001)(19580405001)(74366001)(47976001)(95416001)(49866001)(47736001)(85306002)(83072002)(81686001)(74316001)(85852003)(74502001)(94316002)(80976001)(81816001)(50986001)(93136001)(76796001)(47446002)(80022001)(31966008)(87936001)(92566001)(24736002);DIR:OUT;SFP:1101;SCL:1;SRVR:BL2PR03MB403;H:BL2PR03MB467.namprd03.prod.outlook.com;CLIP:123.151.195.49;FPR:7AED5140.AEF3AEEA.E2F93FA3.88D6BA3B.20290;MLV:sfv;PTR:InfoNoRecords;A:1;MX:1;LANG:en; Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id s263JHDG022339 > -----Original Message----- > From: Shawn Guo [mailto:shawn.guo@linaro.org] > Sent: Thursday, March 06, 2014 9:46 AM > To: Stefan Agner > Cc: daniel.lezcano@linaro.org; tglx@linutronix.de; linux@arm.linux.org.uk; > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Lu > Jingchang-B35083 > Subject: Re: [PATCH] clocksource: vf_pit_timer: use complement for > sched_clock reading > > On Wed, Mar 05, 2014 at 11:11:08PM +0100, Stefan Agner wrote: > > 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 > > Looks correct to me, so > > Acked-by: Shawn Guo > > But I also copied the driver author Jingchang to see if he has any > comment. > > Shawn > The fix is correct, thanks. Best Regards, Jingchang > > --- > > 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) > > -- > > 1.9.0 > > {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I