From: Rob Herring <robherring2@gmail.com>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: linux-kernel@vger.kernel.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Thomas Gleixner <tglx@linutronix.de>,
linuxppc-dev@lists.ozlabs.org,
Russell King <linux@arm.linux.org.uk>,
sfr@canb.auug.org.au,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC 13/14] irq_domain: Remove 'new' irq_domain in favour of the ppc one
Date: Thu, 12 Jan 2012 18:31:28 -0600 [thread overview]
Message-ID: <4F0F7B60.5040701@gmail.com> (raw)
In-Reply-To: <CACxGe6vVSO0cTgPurr6jFoo9QF_W02UaABOFYadCTQGU9dcwmg@mail.gmail.com>
Adding lakml...
On 01/11/2012 03:27 PM, Grant Likely wrote:
> On Wed, Jan 11, 2012 at 2:15 PM, Rob Herring <robherring2@gmail.com> wrote:
>> Grant,
>>
>> On 01/11/2012 02:22 PM, Grant Likely wrote:
>>> This patch removes the simplistic implementation of irq_domains and enables
>>> the powerpc infrastructure for all irq_domain users. The powerpc
>>> infrastructure includes support for complex mappings between Linux and
>>> hardware irq numbers, and can manage allocation of irq_descs.
>>>
>>> This patch also converts the few users of irq_domain_add()/irq_domain_del()
>>> to call irq_domain_add_legacy() instead.
>>
>> So what is the non-legacy way? Legacy implies we don't want to do it
>> that way. I guess until we remove all non-DT platforms with GIC we are
>> stuck with legacy. That seems like it could be a ways out until we get
>> there.
>
> Non-legacy is letting the irq_domain manage the irq_desc allocations.
> Some of the controllers will be easy to convert, some will be more
> difficult. The primary thing that really blocks getting away from the
> legacy method is anything that expects hardcoded #defined irq numbers.
> The goal is to convert all users over to the linear revmap method.
>
So I gave this a spin on highbank. I ran into a couple problems.
I had to revert "irqdesc: Consolidate irq reservation logic" which is in
your branch, but not this series. irq_alloc_desc_from was returning -EEXIST.
The GIC code did not work which I think is specific to using gic_of_init
which makes irq_start = -1. With that it still doesn't work. It dies in
gic_set_type... I've found one problem which I'll reply inline to, but I
think this is a dead end path anyway.
You have removed the irq_alloc_descs call from the GIC which is a step
backwards. Several of the ARM DT enabled platforms are at the point they
can fully support dynamic virq base for each irqchip. I changed the
domain from legacy to linear and got things working. The issue with
linear is for SPARSE_IRQ. The default behavior on ARM for SPARSE_IRQ is
all nr_irqs are allocated at boot time before any controller is
initialized. The only platform with a GIC and requiring SPARSE_IRQ is
shmobile, but it is also the only one that calls irq_alloc_desc
functions for it's interrupts. So I think we are okay there. The problem
occurs when enabling SPARSE_IRQ for a non-DT platform with a GIC and
with irqchips that don't call irq_alloc_desc for their irqs. IMHO, this
should be an okay trade-off. There's no advantage to enabling SPARSE_IRQ
on ARM for platforms that don't require it. All the platforms with a GIC
have active work to convert to DT (except shmobile which I think is
okay), so it's a temporary issue.
Rob
next prev parent reply other threads:[~2012-01-13 0:31 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-11 20:22 [RFC 0/14] Finish up irq_domain generalization Grant Likely
2012-01-11 20:22 ` [RFC 01/14] dt: Make irqdomain less verbose Grant Likely
2012-01-11 20:22 ` [RFC 02/14] irq_domain: Make irq_domain structure match powerpc's irq_host Grant Likely
2012-01-11 20:22 ` [RFC 03/14] irq_domain: convert microblaze from irq_host to irq_domain Grant Likely
2012-01-11 20:22 ` [RFC 04/14] irq_domain/powerpc: Use common irq_domain structure instead of irq_host Grant Likely
2012-01-11 20:22 ` [RFC 05/14] irq_domain/powerpc: eliminate irq_map; use irq_alloc_desc() instead Grant Likely
2012-01-11 20:22 ` [RFC 06/14] irq_domain/powerpc: Eliminate virq_is_host() Grant Likely
2012-01-11 20:22 ` [RFC 07/14] irq_domain: Move irq_domain code from powerpc to kernel/irq Grant Likely
2012-01-11 20:22 ` [RFC 08/14] irqdomain: remove NO_IRQ from irq domain code Grant Likely
2012-01-11 20:22 ` [RFC 09/14] irq_domain: Remove references to old irq_host names Grant Likely
2012-01-11 20:22 ` [RFC 10/14] irq_domain: Replace irq_alloc_host() with revmap-specific initializers Grant Likely
2012-01-11 20:22 ` [RFC 11/14] powerpc: Eliminate NO_IRQ usage Grant Likely
2013-07-25 21:58 ` Geert Uytterhoeven
2013-07-26 3:56 ` Grant Likely
2013-08-23 13:18 ` Geert Uytterhoeven
2013-08-23 13:22 ` Geert Uytterhoeven
2012-01-11 20:22 ` [RFC 12/14] irq_domain: Add support for base irq and hwirq in legacy mappings Grant Likely
2012-01-13 0:37 ` Rob Herring
2012-01-13 0:53 ` Grant Likely
2012-01-11 20:22 ` [RFC 13/14] irq_domain: Remove 'new' irq_domain in favour of the ppc one Grant Likely
2012-01-11 21:15 ` Rob Herring
2012-01-11 21:27 ` Grant Likely
2012-01-13 0:31 ` Rob Herring [this message]
2012-01-13 0:47 ` Grant Likely
2012-01-13 0:53 ` Rob Herring
2012-01-13 2:20 ` Grant Likely
2012-01-17 2:43 ` Michael Bohan
2012-01-17 3:42 ` Benjamin Herrenschmidt
2012-01-18 0:28 ` Grant Likely
2012-01-18 2:16 ` Benjamin Herrenschmidt
2012-01-11 20:22 ` [RFC 14/14] irq_domain: Remove irq_domain_add_simple() Grant Likely
2012-01-11 21:39 ` [RFC 0/14] Finish up irq_domain generalization Randy Dunlap
2012-01-11 20:50 ` Grant Likely
2012-01-11 21:23 ` Grant Likely
2012-01-11 22:48 ` Randy Dunlap
2012-01-12 10:17 ` [RFC 06/14] irq_domain/powerpc: Eliminate virq_is_host() Milton Miller
2012-01-18 0:38 ` Grant Likely
2012-01-18 21:25 ` Grant Likely
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