From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: "Hans J. Koch" <hjk@linutronix.de>,
devicetree-discuss@ozlabs.org, linux-kernel@vger.kernel.org,
linuxppc-dev@ozlabs.org, Greg KH <gregkh@suse.de>
Subject: Re: [PATCH 2/2] uio: add an of_genirq driver
Date: Mon, 15 Jun 2009 19:45:39 +1000 [thread overview]
Message-ID: <1245059139.12400.4.camel@pasglop> (raw)
In-Reply-To: <20090615001207.1829e7b5@lxorguk.ukuu.org.uk>
On Mon, 2009-06-15 at 00:12 +0100, Alan Cox wrote:
> > > + if (!uioinfo->irq)
> > > + uioinfo->irq = UIO_IRQ_NONE;
> >
> > Please don't do this. It's inconsistent if all other UIO drivers require
> > people to use UIO_IRQ_NONE and you also allow zero. UIO_IRQ_NONE was
> > introduced because 0 may be a legal interrupt number on some platforms.
>
> Zero is not a valid IRQ number in the kernel (except in arch specific
> depths). IRQ numbers are also *unsigned* so -1 isn't a safe definition.
>
> Zero means no IRQ. If any old UIO code is assuming otherwise it wants
> fixing.
>
> It is the job of the platform to map a physical IRQ 0 to some other
> representation if it exists outside of arch specific code. This was
> decided some years ago and a large part of the kernel simply doesn't
> support any notion of a real IRQ 0.
Right, and powerpc complies with that rule, so 0 is fine for us.
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
To: Alan Cox <alan-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
Cc: linuxppc-dev-mnsaURCQ41sdnm+yROfE0A@public.gmane.org,
"Hans J. Koch" <hjk-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
devicetree-discuss-mnsaURCQ41sdnm+yROfE0A@public.gmane.org,
Greg KH <gregkh-l3A5Bk7waGM@public.gmane.org>
Subject: Re: [PATCH 2/2] uio: add an of_genirq driver
Date: Mon, 15 Jun 2009 19:45:39 +1000 [thread overview]
Message-ID: <1245059139.12400.4.camel@pasglop> (raw)
In-Reply-To: <20090615001207.1829e7b5-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
On Mon, 2009-06-15 at 00:12 +0100, Alan Cox wrote:
> > > + if (!uioinfo->irq)
> > > + uioinfo->irq = UIO_IRQ_NONE;
> >
> > Please don't do this. It's inconsistent if all other UIO drivers require
> > people to use UIO_IRQ_NONE and you also allow zero. UIO_IRQ_NONE was
> > introduced because 0 may be a legal interrupt number on some platforms.
>
> Zero is not a valid IRQ number in the kernel (except in arch specific
> depths). IRQ numbers are also *unsigned* so -1 isn't a safe definition.
>
> Zero means no IRQ. If any old UIO code is assuming otherwise it wants
> fixing.
>
> It is the job of the platform to map a physical IRQ 0 to some other
> representation if it exists outside of arch specific code. This was
> decided some years ago and a large part of the kernel simply doesn't
> support any notion of a real IRQ 0.
Right, and powerpc complies with that rule, so 0 is fine for us.
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: linuxppc-dev@ozlabs.org, "Hans J. Koch" <hjk@linutronix.de>,
linux-kernel@vger.kernel.org, devicetree-discuss@ozlabs.org,
Greg KH <gregkh@suse.de>
Subject: Re: [PATCH 2/2] uio: add an of_genirq driver
Date: Mon, 15 Jun 2009 19:45:39 +1000 [thread overview]
Message-ID: <1245059139.12400.4.camel@pasglop> (raw)
In-Reply-To: <20090615001207.1829e7b5@lxorguk.ukuu.org.uk>
On Mon, 2009-06-15 at 00:12 +0100, Alan Cox wrote:
> > > + if (!uioinfo->irq)
> > > + uioinfo->irq = UIO_IRQ_NONE;
> >
> > Please don't do this. It's inconsistent if all other UIO drivers require
> > people to use UIO_IRQ_NONE and you also allow zero. UIO_IRQ_NONE was
> > introduced because 0 may be a legal interrupt number on some platforms.
>
> Zero is not a valid IRQ number in the kernel (except in arch specific
> depths). IRQ numbers are also *unsigned* so -1 isn't a safe definition.
>
> Zero means no IRQ. If any old UIO code is assuming otherwise it wants
> fixing.
>
> It is the job of the platform to map a physical IRQ 0 to some other
> representation if it exists outside of arch specific code. This was
> decided some years ago and a large part of the kernel simply doesn't
> support any notion of a real IRQ 0.
Right, and powerpc complies with that rule, so 0 is fine for us.
Cheers,
Ben.
next prev parent reply other threads:[~2009-06-15 9:46 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-12 0:04 [PATCH 0/2] add OF wrapper for uio-pdrv-genirq Wolfram Sang
2009-06-12 0:04 ` [PATCH 1/2] uio/pdrv_genirq: Refactor probe routine to expose a generic part Wolfram Sang
2009-06-12 0:04 ` Wolfram Sang
2009-06-12 0:04 ` Wolfram Sang
2009-06-14 12:15 ` Hans J. Koch
2009-06-14 12:15 ` Hans J. Koch
2009-06-12 0:04 ` [PATCH 2/2] uio: add an of_genirq driver Wolfram Sang
2009-06-12 0:04 ` Wolfram Sang
2009-06-12 0:04 ` Wolfram Sang
2009-06-14 12:21 ` Hans J. Koch
2009-06-14 12:21 ` Hans J. Koch
2009-06-14 17:14 ` Wolfram Sang
2009-06-14 17:14 ` Wolfram Sang
2009-06-14 17:14 ` Wolfram Sang
2009-06-14 18:33 ` Hans J. Koch
2009-06-14 18:33 ` Hans J. Koch
2009-06-14 18:33 ` Hans J. Koch
2009-06-14 19:05 ` Wolfram Sang
2009-06-14 19:05 ` Wolfram Sang
2009-06-14 19:05 ` Wolfram Sang
2009-06-14 19:23 ` Hans J. Koch
2009-06-14 19:23 ` Hans J. Koch
2009-06-14 19:23 ` Hans J. Koch
2009-06-14 19:36 ` Wolfgang Grandegger
2009-06-14 19:36 ` Wolfgang Grandegger
2009-06-14 19:36 ` Wolfgang Grandegger
2009-06-14 20:34 ` Hans J. Koch
2009-06-14 20:34 ` Hans J. Koch
2009-06-14 20:34 ` Hans J. Koch
2009-06-14 22:00 ` Wolfram Sang
2009-06-14 22:00 ` Wolfram Sang
2009-06-14 22:00 ` Wolfram Sang
2009-06-14 23:01 ` Hans J. Koch
2009-06-14 23:01 ` Hans J. Koch
2009-06-14 23:01 ` Hans J. Koch
2009-06-14 23:46 ` Wolfram Sang
2009-06-14 23:46 ` Wolfram Sang
2009-06-14 23:46 ` Wolfram Sang
2009-06-14 23:50 ` Hans J. Koch
2009-06-14 23:50 ` Hans J. Koch
2009-06-14 23:50 ` Hans J. Koch
2009-06-14 19:27 ` Greg KH
2009-06-14 19:27 ` Greg KH
2009-06-14 21:46 ` Wolfram Sang
2009-06-14 21:46 ` Wolfram Sang
2009-06-14 21:46 ` Wolfram Sang
2009-06-14 23:12 ` Alan Cox
2009-06-14 23:12 ` Alan Cox
2009-06-14 23:12 ` Alan Cox
2009-06-14 23:45 ` Hans J. Koch
2009-06-14 23:45 ` Hans J. Koch
2009-06-14 23:45 ` Hans J. Koch
2009-06-15 8:44 ` Alan Cox
2009-06-15 8:44 ` Alan Cox
2009-06-15 8:44 ` Alan Cox
2009-06-15 9:45 ` Benjamin Herrenschmidt [this message]
2009-06-15 9:45 ` Benjamin Herrenschmidt
2009-06-15 9:45 ` Benjamin Herrenschmidt
2009-06-14 14:40 ` Grant Likely
2009-06-14 14:40 ` Grant Likely
2009-06-14 14:40 ` Grant Likely
2009-06-16 9:04 ` Wolfram Sang
2009-06-16 9:04 ` Wolfram Sang
2009-06-16 9:04 ` Wolfram Sang
2009-06-16 12:46 ` Grant Likely
2009-06-16 12:46 ` Grant Likely
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