From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751927AbbCIH7N (ORCPT ); Mon, 9 Mar 2015 03:59:13 -0400 Received: from mail-ob0-f182.google.com ([209.85.214.182]:44967 "EHLO mail-ob0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751012AbbCIH7K (ORCPT ); Mon, 9 Mar 2015 03:59:10 -0400 MIME-Version: 1.0 In-Reply-To: <20150220154038.GE18111@kroah.com> References: <1424275938-3337-1-git-send-email-linus.walleij@linaro.org> <20150220154038.GE18111@kroah.com> Date: Mon, 9 Mar 2015 08:59:09 +0100 Message-ID: Subject: Re: [PATCH] drivers: platform: parse IRQ flags from resources From: Linus Walleij To: Greg Kroah-Hartman , Grant Likely Cc: "linux-kernel@vger.kernel.org" , Thomas Gleixner , Robert Jarzmik , "David S. Miller" , Arnd Bergmann Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 20, 2015 at 4:40 PM, Greg Kroah-Hartman wrote: > On Wed, Feb 18, 2015 at 05:12:18PM +0100, Linus Walleij wrote: >> This fixes a regression from the net subsystem: >> After commit d52fdbb735c36a209f36a628d40ca9185b349ba7 >> "smc91x: retrieve IRQ and trigger flags in a modern way" >> a regression would appear on some legacy platforms such >> as the ARM PXA Zylonite that specify IRQ resources like >> this: >> >> static struct resource r = { >> .start = X, >> .end = X, >> .flags = IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHEDGE, >> }; >> >> The previous code would retrieve the resource and parse >> the high edge setting in the SMC91x driver, a use pattern >> that means every driver specifying an IRQ flag from a >> static resource need to parse resource flags and apply >> them at runtime. >> >> As we switched the code to use IRQ descriptors to retrieve >> the the trigger type like this: >> >> irqd_get_trigger_type(irq_get_irq_data(...)); >> >> the code would work for new platforms using e.g. device >> tree as the backing irq descriptor would have its flags >> properly set, whereas this kind of oldstyle static >> resources at no point assign the trigger flags to the >> corresponding IRQ descriptor. >> >> To make the behaviour identical on modern device tree >> and legacy static platform data platforms, modify >> platform_get_irq() to assign the trigger flags to the >> irq descriptor when a client looks up an IRQ from static >> resources. >> >> Fixes: d52fdbb735c3 ("smc91x: retrieve IRQ and trigger flags in a modern way") >> Tested-by: Robert Jarzmik >> Signed-off-by: Linus Walleij >> --- >> Greg/Grant: I'm a bit uncertain here. It's kind of >> unintuitive that the platform_get_irq() function go around >> setting trigger flags on IRQ descriptors, but it is *also* >> unintuitive that the descriptor has all the right flags >> from a device tree but not from an identical static >> resource. And it is bloated to have resource parsing in >> each and every driver. The alternative is to revert >> the offending patch and live with some resource parsing >> all over the place. (Such a patch is posted.) >> --- >> drivers/base/platform.c | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/drivers/base/platform.c b/drivers/base/platform.c >> index 9421fed40905..e68ab79df28b 100644 >> --- a/drivers/base/platform.c >> +++ b/drivers/base/platform.c >> @@ -101,6 +101,15 @@ int platform_get_irq(struct platform_device *dev, unsigned int num) >> } >> >> r = platform_get_resource(dev, IORESOURCE_IRQ, num); >> + /* >> + * The resources may pass trigger flags to the irqs that need >> + * to be set up. It so happens that the trigger flags for >> + * IORESOURCE_BITS correspond 1-to-1 to the IRQF_TRIGGER* >> + * settings. >> + */ >> + if (r && r->flags & IORESOURCE_BITS) >> + irqd_set_trigger_type(irq_get_irq_data(r->start), >> + r->flags & IORESOURCE_BITS); > > Ah, found this now. > > I'll defer to Grant as to what to do here, as I have no idea... OK no answer, Greg can you just merge this patch then, because I say it's my best bet for a solution. Yours, Linus Walleij