On Thu, Jan 12, 2012 at 5:31 PM, Rob Herring <robherri...@gmail.com> wrote: > Adding lakml... > > On 01/11/2012 03:27 PM, Grant Likely wrote: >> On Wed, Jan 11, 2012 at 2:15 PM, Rob Herring <robherri...@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.
Hmmm... I thought I sorted that out. Thanks for letting me know. > > 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. Haha, I'm not surprised. That last patch was only compile tested on platforms using the gic. I'm not surprised that I flubbed it. > 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 I hadn't actually intended to remove the irq_alloc_descs in this patch. That was a leftover hunk from when I was playing with going straight to irq_domain_add_linear(). For this specific patch, I'll put the alloc back in and test it that way. A follow-on patch can do a proper conversion to the linear revmap. > 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. Actually, I believe Thomas' long term goal is to always enable SPARSE_IRQ and remove the option entirely, so it should still be properly resolved. I'll take a look next week if I don't get to it tomorrow. I need to resurrect my vexpress qemu test environment so I can test the permutations. g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
