Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753545Ab3F1UNL (ORCPT ); Fri, 28 Jun 2013 16:13:11 -0400 Received: from www.linutronix.de ([62.245.132.108]:48171 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752148Ab3F1UNK (ORCPT ); Fri, 28 Jun 2013 16:13:10 -0400 Date: Fri, 28 Jun 2013 22:13:08 +0200 (CEST) From: Thomas Gleixner To: Maxime Ripard cc: John Stultz , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Emilio Lopez , kevin@allwinnertech.com, sunny@allwinnertech.com, shuge@allwinnertech.com, linux-sunxi@googlegroups.com Subject: Re: [PATCHv2 4/8] clocksource: sun4i: Fix the next event code In-Reply-To: <1372449386-1334-5-git-send-email-maxime.ripard@free-electrons.com> Message-ID: References: <1372449386-1334-1-git-send-email-maxime.ripard@free-electrons.com> <1372449386-1334-5-git-send-email-maxime.ripard@free-electrons.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001,URIBL_BLOCKED=0.001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1881 Lines: 55 On Fri, 28 Jun 2013, Maxime Ripard wrote: > The next_event logic was setting the next interval to fire in the > current timer value instead of the interval value register, which is > obviously wrong. Ok. > Plus the logic to set the actual value was wrong as well, so this > code has always been broken. This lacks an explanation why the logic is wrong and what the actual fix is. > Signed-off-by: Maxime Ripard > --- > drivers/clocksource/sun4i_timer.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/clocksource/sun4i_timer.c b/drivers/clocksource/sun4i_timer.c > index 84ace76..695c8c8 100644 > --- a/drivers/clocksource/sun4i_timer.c > +++ b/drivers/clocksource/sun4i_timer.c > @@ -16,6 +16,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -61,9 +62,14 @@ static void sun4i_clkevt_mode(enum clock_event_mode mode, > static int sun4i_clkevt_next_event(unsigned long evt, > struct clock_event_device *unused) > { > - u32 u = readl(timer_base + TIMER_CTL_REG(0)); > - writel(evt, timer_base + TIMER_CNTVAL_REG(0)); > - writel(u | TIMER_CTL_ENABLE | TIMER_CTL_AUTORELOAD, > + u32 val = readl(timer_base + TIMER_CTL_REG(0)); > + writel(val & ~TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG(0)); > + udelay(1); That udelay() is more than suspicious. Is there really no other way to deal with that hardware? If no, you really need to put a proper explanation for that into the code. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/