On Tuesday 02 September 2014 15:22:31 Andrew Bresticker wrote: > 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. It shouldn't be hard to change the existing code to use irq domain accessors. The main part is probably just to replace 'd->irq - gic_irq_base' with 'd->hwirq', in case you make up your mind about it again. Arnd
