From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: Michal Simek <monstr@monstr.eu>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Ralf Baechle <ralf@linux-mips.org>,
hpa@zytor.com, Dirk Brandewie <dirk.brandewie@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
linuxppc-dev@lists.ozlabs.org,
devicetree-discuss@lists.ozlabs.org
Subject: Re: [PATCH 4/6] dt: generalize irq_of_create_mapping()
Date: Thu, 05 May 2011 10:43:41 +1000 [thread overview]
Message-ID: <1304556221.2513.395.camel@pasglop> (raw)
In-Reply-To: <20110504160502.GC3317@ponder.secretlab.ca>
On Wed, 2011-05-04 at 10:05 -0600, Grant Likely wrote:
> > I think you are going the wrong way around.
> >
> > First thing first, is to make the irq domain / mapping API generic
> > without the OF bits.
> >
> > IE. move the IRQ domain generically, get rid of irq_map by putting
> the
> > domain ptr & hw numbers in the irq desc/data etc...
> >
> > Then you can move over the OF specific bits which are optional and
> > orthogonal to a large extent.
>
> As discussed in my other reply, I disagree. There isn't an immediate
> need for the mapping interface in common code. It would be useful,
> sure, for some interrupt controllers, but for many of them
> irq_alloc_descs() and an irq_base value is all the functionality that
> is needed, and irq_host doesn't gain anything.
No but the concept of domain is a pre-requisite. Even if it's an opaque
data structure. And I don't want to have it be some "of" specific thing.
> The OF translation on the other hand is needed immediately by several
> architectures and are very much non-optional in that regard.
But it relies on having an underlying mapping. I don't see how you can
do one without the other, even if your mapping in effect is just an
offset.
And it is -not- related to OF.
Whether you obtain that your interrupt you are interested it is
interrupt 5 of your PIC "foo" via the device-tree or any other way (an
arch quirk for example), you need the mechanism to associate them
together, whether it's a simple offset as you propose (I'm ok with that
for simple things, I just didn't think it was the right approach for
powerpc but it's perfectly valid as an option generically) or a more
complex radix-tree style mapping.
Thus sort out the mapping interfaces first. _Then_ layout the
device-tree bits on top.
The basic parsing for the DT is already there. It will return a parent
node and a __be32* pointer.
Cheers,
Ben.
next prev parent reply other threads:[~2011-05-05 0:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-28 20:01 [PATCH 0/6] General device tree irq domain infrastructure Grant Likely
2011-04-28 20:01 ` [PATCH 1/6] powerpc: stop exporting irq_map Grant Likely
2011-05-03 1:44 ` Benjamin Herrenschmidt
2011-04-28 20:01 ` [PATCH 2/6] powerpc: make irq_{alloc, free}_virt private and remove count argument Grant Likely
2011-05-03 1:47 ` Benjamin Herrenschmidt
2011-05-04 15:59 ` Grant Likely
2011-05-05 0:39 ` Benjamin Herrenschmidt
2011-04-28 20:01 ` [PATCH 3/6] powerpc: Make struct irq_host semi-private by moving into irqhost.h Grant Likely
2011-05-03 1:48 ` Benjamin Herrenschmidt
2011-04-28 20:02 ` [PATCH 4/6] dt: generalize irq_of_create_mapping() Grant Likely
2011-05-03 1:50 ` Benjamin Herrenschmidt
2011-05-04 16:05 ` Grant Likely
2011-05-05 0:43 ` Benjamin Herrenschmidt [this message]
2011-04-28 20:02 ` [PATCH 5/6] powerpc: move irq_alloc_descs_at() call into irq_alloc_virt() Grant Likely
2011-04-28 20:02 ` [PATCH 6/6] powerpc: use irq_alloc_desc() to manage irq allocations Grant Likely
2011-04-29 16:16 ` [PATCH 0/6] General device tree irq domain infrastructure Sebastian Andrzej Siewior
2011-04-29 17:43 ` Grant Likely
2011-05-03 1:43 ` Benjamin Herrenschmidt
2011-05-04 15:52 ` Grant Likely
2011-05-05 0:39 ` Benjamin Herrenschmidt
2011-05-05 8:37 ` Thomas Gleixner
2011-05-05 14:07 ` Grant Likely
2011-05-05 14:14 ` Sebastian Andrzej Siewior
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