[PATCH] Initial generic hypertransport interrupt support

This patch implements two functions ht_create_irq and ht_destroy_irq for
use by drivers.  Several other functions are implemented as helpers for
arch specific irq_chip handlers.

The driver for the card I tested this on isn't yet ready to be merged.
However this code is and hypertransport irqs are in use in a few other
places in the kernel.  Not that any of this will get merged before 2.6.19

Because the ipath-ht400 is slightly out of spec this code will need to be
generalized to work there.

I think all of the powerpc uses are for a plain interrupt controller in a
chipset so support for native hypertransport devices is a little less
interesting.

However I think this is a half way decent model on how to separate arch
specific and generic helper code, and I think this is a functional model of
how to get the architecture dependencies out of the msi code.

[akpm@osdl.org: Kconfig fix]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg KH <greg@kroah.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 2aabe90..9b34bc8 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -681,6 +681,23 @@
 
 #endif
 
+#ifdef CONFIG_HT_IRQ
+/* Helper functions.. */
+void write_ht_irq_low(unsigned int irq, u32 data);
+void write_ht_irq_high(unsigned int irq, u32 data);
+u32  read_ht_irq_low(unsigned int irq);
+u32  read_ht_irq_high(unsigned int irq);
+void mask_ht_irq(unsigned int irq);
+void unmask_ht_irq(unsigned int irq);
+
+/* The functions a driver should call */
+int  ht_create_irq(struct pci_dev *dev, int idx);
+void ht_destroy_irq(unsigned int irq);
+
+/* The arch hook for getting things started */
+int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev);
+#endif /* CONFIG_HT_IRQ */
+
 extern void pci_block_user_cfg_access(struct pci_dev *dev);
 extern void pci_unblock_user_cfg_access(struct pci_dev *dev);