On 01/12/2012 06:47 PM, Grant Likely wrote: > 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. >
Agreed. I think that is the path to the removing include of mach/irqs.h as well, and I have a patch series to do just that when SPARSE_IRQ is enabled. It also has the problem of breaking platforms which don't NEED to enable SPARSE_IRQ. I'll try to get it sent out soon. Rob _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
