On Mon, Sep 1, 2014 at 5:08 PM, Andrew Bresticker <abrestic@xxxxxxxxxxxx> wrote: > On Mon, Sep 1, 2014 at 1:34 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: >> On Sunday 31 August 2014 11:54:04 Andrew Bresticker wrote: >>> On Sat, Aug 30, 2014 at 12:57 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: >>> > On Friday 29 August 2014 15:14:31 Andrew Bresticker wrote: >>> >> Define a generic MIPS_GIC_IRQ_BASE which is suitable for Malta and >>> >> the upcoming Danube board in <mach-generic/irq.h>. Since Sead-3 is >>> >> different and uses a MIPS_GIC_IRQ_BASE equal to the CPU IRQ base (0), >>> >> define its MIPS_GIC_IRQ_BASE in <mach-sead3/irq.h>. >>> >> >>> >> Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx> >>> >> >>> > >>> > Why do you actually have to hardwire an IRQ base? Can't you move >>> > to the linear irqdomain code for DT based MIPS systems yet? >>> >>> Neither Malta nor SEAD-3 use device-tree for interrupts yet, so they >>> still require a hard-coded IRQ base. For boards using device-tree, I >>> stuck with a legacy IRQ domain as it allows most of the existing GIC >>> irqchip code to be reused. >> >> I see. Note that we now have irq_domain_add_simple(), which should >> do the right think in either case: use a legacy domain when a >> nonzero base is provided for the old boards, but use the simple >> domain when probed from DT without an irq base. >> >> This makes the latter case more memory efficient (it avoids >> allocating the irq descriptors for every possibly but unused >> IRQ number) and helps ensure that you don't accidentally rely >> on hardcoded IRQ numbers for the DT based machines, which would >> be considered a bug. > > Ah, ok. It looks like add_simple() is what I want then. Actually, never mind. To re-use the existing GIC irqchip code I want a legacy IRQ domain.
