[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, 11 insertions, 2 deletions

diff --git a/include/asm-sparc64/irq.h b/include/asm-sparc64/irq.h
index d66c7cd820c2..9edcd90495f7 100644
--- a/include/asm-sparc64/irq.h
+++ b/include/asm-sparc64/irq.h
@@ -98,13 +98,22 @@ extern struct ino_bucket ivector_table[NUM_IVECS];
 #define __bucket(irq) ((struct ino_bucket *)(unsigned long)(irq))
 #define __irq(bucket) ((unsigned int)(unsigned long)(bucket))
 
-#define NR_IRQS    16
+/* The largest number of unique interrupt sources we support.
+ * If this needs to ever be larger than 255, you need to change
+ * the type of ino_bucket->virt_irq as appropriate.
+ *
+ * ino_bucket->virt_irq allocation is made during {sun4v_,}build_irq().
+ */
+#define NR_IRQS    255
 
+extern void irq_install_pre_handler(int virt_irq,
+                                    void (*func)(struct ino_bucket *, void *, void *),
+                                    void *arg1, void *arg2);
 #define irq_canonicalize(irq)   (irq)
 extern void disable_irq(unsigned int);
 #define disable_irq_nosync disable_irq
 extern void enable_irq(unsigned int);
-extern unsigned int build_irq(int inofixup, unsigned long iclr, unsigned long imap);
+extern unsigned int build_irq(int inofixup, unsigned long iclr, unsigned long imap, unsigned char flags);
 extern unsigned int sun4v_build_irq(u32 devhandle, unsigned int devino, unsigned char flags);
 extern unsigned int sbus_build_irq(void *sbus, unsigned int ino);