From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754789AbaEHR2J (ORCPT ); Thu, 8 May 2014 13:28:09 -0400 Received: from top.free-electrons.com ([176.31.233.9]:40228 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753348AbaEHR2G (ORCPT ); Thu, 8 May 2014 13:28:06 -0400 Message-ID: <536BBEA4.6080908@free-electrons.com> Date: Thu, 08 May 2014 19:28:04 +0200 From: Boris BREZILLON User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Johan Hovold CC: Bryan Evenson , Andrew Victor , Nicolas Ferre , Jean-Christophe Plagniol-Villard , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ARM: at91: fix rtc irq mask for sam9x5 SoCs References: <957b209589094df48ddedbc57c6ccdfd@BLUPR05MB037.namprd05.prod.outlook.com> <1399479649-3247-1-git-send-email-boris.brezillon@free-electrons.com> <20140508154912.GA6776@localhost> In-Reply-To: <20140508154912.GA6776@localhost> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/05/2014 17:49, Johan Hovold wrote: > On Wed, May 07, 2014 at 06:20:49PM +0200, Boris BREZILLON wrote: >> The RTC IMR register is not reliable on sam9x5 SoCs, hence why me have to >> mask all interrupts no matter what IMR claims about already masked irqs. > Crap, I totally forgot about this. Doug reported the problem off-list > back in December, but it got lost somehow. Sorry. No problem. BTW, I started to work on a more generic solution to handle these muxed irqs issues (see https://lkml.org/lkml/2014/3/28/353). Could you take a look at it (I'm still not happy with the proposed DT bindings, but this can be discussed)? >> Signed-off-by: Boris BREZILLON >> Reported-by: Bryan Evenson >> --- >> Hello Bryan, >> >> Yet another patch for you ;-). >> >> As usual, could you tell me if it fixes your bug. >> >> BTW, thanks for your tests. >> >> Best Regards, >> >> Boris >> >> arch/arm/mach-at91/sysirq_mask.c | 7 +------ >> 1 file changed, 1 insertion(+), 6 deletions(-) >> >> diff --git a/arch/arm/mach-at91/sysirq_mask.c b/arch/arm/mach-at91/sysirq_mask.c >> index 2ba694f..eb3d2a5 100644 >> --- a/arch/arm/mach-at91/sysirq_mask.c >> +++ b/arch/arm/mach-at91/sysirq_mask.c >> @@ -37,12 +37,7 @@ void __init at91_sysirq_mask_rtc(u32 rtc_base) >> if (!base) >> return; >> >> - mask = readl_relaxed(base + AT91_RTC_IMR); >> - if (mask) { >> - pr_info("AT91: Disabling rtc irq\n"); >> - writel_relaxed(mask, base + AT91_RTC_IDR); >> - (void)readl_relaxed(base + AT91_RTC_IMR); /* flush */ >> - } >> + writel_relaxed(0x1f, base + AT91_RTC_IDR); > I believe this is the right way to handle this hardware bug (IMR is > always read as 0 on one particular SoC), but please document this in a > comment. Sure, I'll quote atmel's datasheet describing the errata. > > You should also keep the flush (read of IMR) regardless (to make sure > the write has reached the peripheral), and remember to remove the now > unused mask variable. Does it has something to do with memory barriers ? If so, why not using writel instead of writel_relaxed ? If not, could you point out where it is described in the datasheet ? Best Regards, Boris > >> iounmap(base); >> } > Thanks, > Johan -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com