x86, pic: Introduce legacy_pic abstraction

This patch makes i8259A like legacy programmable interrupt controller
code into a driver so that legacy pic functions can be selected at
runtime based on platform information, such as HW subarchitecure ID.
Default structure of legacy_pic maintains the current code path for
x86pc.

Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
LKML-Reference: <43F901BD926A4E43B106BF17856F07559FB80D03@orsmsx508.amr.corp.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/x86/include/asm/i8259.h b/arch/x86/include/asm/i8259.h
index 58d7091eeb1f..e8a3e05c2882 100644
--- a/arch/x86/include/asm/i8259.h
+++ b/arch/x86/include/asm/i8259.h
@@ -57,6 +57,19 @@ static inline void outb_pic(unsigned char value, unsigned int port)
 
 extern struct irq_chip i8259A_chip;
 
+struct legacy_pic {
+        int nr_legacy_irqs;
+        struct irq_chip *chip;
+        void (*mask_all)(void);
+        void (*restore_mask)(void);
+        void (*init)(int auto_eoi);
+        int (*irq_pending)(unsigned int irq);
+        void (*make_irq)(unsigned int irq);
+};
+
+extern struct legacy_pic *legacy_pic;
+extern struct legacy_pic null_legacy_pic;
+
 extern void mask_8259A(void);
 extern void unmask_8259A(void);