[SPARC64]: Virtualize IRQ numbers.

Inspired by PowerPC XICS interrupt support code.

All IRQs are virtualized in order to keep NR_IRQS from needing
to be too large.  Interrupts on sparc64 are arbitrary 11-bit
values, but we don't need to define NR_IRQS to 2048 if we
virtualize the IRQs.

As PCI and SBUS controller drivers build device IRQs, we divy
out virtual IRQ numbers incrementally starting at 1.  Zero is
a special virtual IRQ used for the timer interrupt.

So device drivers all see virtual IRQs, and all the normal
interfaces such as request_irq(), enable_irq(), etc. translate
that into a real IRQ number in order to configure the IRQ.

At this point knowledge of the struct ino_bucket is almost
entirely contained within arch/sparc64/kernel/irq.c  There are
a few small bits in the PCI controller drivers that need to
be swept away before we can remove ino_bucket's definition
out of asm-sparc64/irq.h and privately into kernel/irq.c

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 5 deletions

diff --git a/arch/sparc64/kernel/pci_psycho.c b/arch/sparc64/kernel/pci_psycho.c
index 5743e1316a93..f2d1097f541d 100644
--- a/arch/sparc64/kernel/pci_psycho.c
+++ b/arch/sparc64/kernel/pci_psycho.c
@@ -280,7 +280,6 @@ static unsigned int psycho_irq_build(struct pci_pbm_info *pbm,
                                      struct pci_dev *pdev,
                                      unsigned int ino)
 {
-        struct ino_bucket *bucket;
         unsigned long imap, iclr;
         unsigned long imap_off, iclr_off;
         int inofixup = 0;
@@ -309,10 +308,7 @@ static unsigned int psycho_irq_build(struct pci_pbm_info *pbm,
         if ((ino & 0x20) == 0)
                 inofixup = ino & 0x03;
 
-        bucket = __bucket(build_irq(inofixup, iclr, imap));
-        bucket->flags |= IBF_PCI;
-
-        return __irq(bucket);
+        return build_irq(inofixup, iclr, imap, IBF_PCI);
 }
 
 /* PSYCHO error handling support. */