From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [PATCH 6/7] spi/mpc8xxx: don't check platform_get_irq's return value against zero Date: Wed, 16 Dec 2009 20:18:39 +0100 Message-ID: <20091216191839.GA23614@pengutronix.de> References: <1260979809-24811-1-git-send-email-u.kleine-koenig@pengutronix.de> <1260979809-24811-2-git-send-email-u.kleine-koenig@pengutronix.de> <1260979809-24811-3-git-send-email-u.kleine-koenig@pengutronix.de> <1260979809-24811-4-git-send-email-u.kleine-koenig@pengutronix.de> <1260979809-24811-5-git-send-email-u.kleine-koenig@pengutronix.de> <1260979809-24811-6-git-send-email-u.kleine-koenig@pengutronix.de> <20091216163229.GA26350@oksana.dev.rtsoft.ru> <20091216174904.GB26325@pengutronix.de> <20091216182034.GA7590@oksana.dev.rtsoft.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-kernel@vger.kernel.org, David Vrabel , Greg Kroah-Hartman , David Brownell , Grant Likely , Kumar Gala , Andrew Morton , spi-devel-general@lists.sourceforge.net, Linus Torvalds To: Anton Vorontsov Return-path: Content-Disposition: inline In-Reply-To: <20091216182034.GA7590@oksana.dev.rtsoft.ru> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org Hi Anton, On Wed, Dec 16, 2009 at 09:20:34PM +0300, Anton Vorontsov wrote: > On Wed, Dec 16, 2009 at 06:49:04PM +0100, Uwe Kleine-K=F6nig wrote: > [...] > > > Noooooo... :-( > > >=20 > > > Please revert 305b3228f9ff4d59f49e6d34a7034d44ee8ce2f0 instead, > > > and fix platforms to remap HWIRQ0 to something that is not VIRQ0. > > >=20 > > > IRQ0 is invalid for everything that is outside of arch/*. > > >=20 > > > http://lkml.org/lkml/2005/11/22/159 > > > http://lkml.org/lkml/2005/11/22/213 > > > http://lkml.org/lkml/2005/11/22/227 > > First note that my check is safe with both variants (e.g. it does t= he > > right thing independent of the error being signaled by 0 or > > -ESOMETHING.) > >=20 > > Then arch/arm/mach-pxa/devices.c has: > >=20 > > static struct resource pxa27x_resource_ssp3[] =3D { > > ... > > [1] =3D { > > .start =3D IRQ_SSP3, > > .end =3D IRQ_SSP3, > > .flags =3D IORESOURCE_IRQ, > > }, > > ... > > } > >=20 > > with IRQ_SSP3 being zero (sometimes). The driver is implemented in > > arch/arm/mach-pxa/ssp.c and uses platform_get_irq. >=20 > So fix this *one* driver? Implement arm-specific platform_get_irq() a= s > a band-aid. Or better, implement virtual irqs <-> hardware irqs mappi= ng > for ARM. >=20 > [...] > > I'm a bit annoyed as this is the third time[1] this month this irq0 > > discussion pops up for me. I think people see that irq0 is involve= d > > somehow, start wailing and stop seeing the issues being fixed. >=20 > For this particular driver, there is NO issue whatsoever. It is > only used for PowerPC, which has VIRQ0 =3D=3D invalid IRQ. And note > that there still could be HWIRQ0 on PowerPC, but it is *never* > mapped to VIRQ0. Yes, there is an issue. If the platform device doesn't have a resource specifing the irq, platform_get_irq returns -ENXIO. So in the driver (unsigned)(-ENXIO) is passed to mpc8xxx_spi_probe as (!(-ENXIO)) is false and so the error isn't catched. > [...] > > [1] one is: > > http://thread.gmane.org/gmane.linux.kernel/924739 >=20 > No wonder the discussion popped up. You're adding some ugly > #ifdef stuff that adds some arch-specific knowledge to a generic > code. I wouldn't argue if people objected to the arch-specific #ifdef. The arch-specific code is already in there and I don't object to just removing it. But answering that irq0 must not be used isn't helpful. =20 Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig = | Industrial Linux Solutions | http://www.pengutronix.= de/ |