1 files changed, 82 insertions, 0 deletions
diff --git a/ioapic.c b/ioapic.c
new file mode 100644
index 0000000..776f895
--- /dev/null
+++ b/ioapic.c
@@ -0,0 +1,82 @@
+#include "types.h"
+#include "mp.h"
+#include "defs.h"
+#include "x86.h"
+#include "traps.h"
+#include "ioapic.h"
+
+struct ioapic {
+  uint ioregsel;  uint p01; uint p02; uint p03;
+  uint iowin;     uint p11; uint p12; uint p13;
+};
+
+
+#define	IOAPIC_REDTBL_LO(i)	(IOAPIC_REDTBL + (i) * 2)
+#define	IOAPIC_REDTBL_HI(i)	(IOAPIC_REDTBL_LO(i) + 1)
+
+static uint
+ioapic_read(struct ioapic *io, int reg)
+{
+  io->ioregsel = reg;
+  return (io->iowin);
+}
+
+static void
+ioapic_write(struct ioapic *io, int reg, uint val)
+{
+  io->ioregsel = reg;
+  io->iowin = val;
+}
+
+void
+ioapic_init(void)
+{
+  struct ioapic *io;
+  uint l, h;
+  int nintr;
+  uchar id;
+  int i;
+
+  io = (struct ioapic *) IO_APIC_BASE;
+  l = ioapic_read(io, IOAPIC_VER);
+  nintr =  ((l & IOART_VER_MAXREDIR) >> MAXREDIRSHIFT) + 1;
+  id = ioapic_read(io, IOAPIC_ID) >> APIC_ID_SHIFT;	
+  if (id != ioapic_id)
+    panic ("ioapic_init: id isn't equal to ioapic_id\n");
+  cprintf ("ioapic VER: 0x%x id %d nintr %d\n", l, id, nintr);
+  for (i = 0; i < nintr; i++) {
+    // active-hi and edge-triggered for ISA interrupts
+    // Assume that pin 0 on the first I/O APIC is an ExtINT pin.
+    // Assume that pins 1-15 are ISA interrupts and that all
+    l = ioapic_read(io, IOAPIC_REDTBL_LO(i));
+    l = l & ~IOART_INTMASK;  // allow INTs
+    l |= IOART_INTMSET;
+    l = l & ~IOART_INTPOL;   // active hi
+    l = l & ~IOART_TRGRMOD;  // edgee triggered
+    l = l & ~IOART_DELMOD;   // fixed
+    l = l & ~IOART_DESTMOD;  // physical mode
+    l = l | (IRQ_OFFSET + i); // vector
+    ioapic_write(io, IOAPIC_REDTBL_LO(i), l);
+    h = ioapic_read(io, IOAPIC_REDTBL_HI(i));
+    h &= ~IOART_DEST;
+    ioapic_write(io, IOAPIC_REDTBL_HI(i), h);
+    //    cprintf("intr %d: lo 0x%x hi 0x%x\n", i, l, h);
+  }
+}
+
+void
+ioapic_enable (int irq, int cpu)
+{
+  uint l, h;
+  struct ioapic *io;
+
+  io = (struct ioapic *) IO_APIC_BASE;
+  l = ioapic_read(io, IOAPIC_REDTBL_LO(irq));
+  l = l & ~IOART_INTMASK;  // allow INTs
+  ioapic_write(io, IOAPIC_REDTBL_LO(irq), l);
+  h = ioapic_read(io, IOAPIC_REDTBL_HI(irq));
+  h &= ~IOART_DEST;
+  h |= (cpu << APIC_ID_SHIFT);  // for fun, disk interrupts to cpu 1
+  ioapic_write(io, IOAPIC_REDTBL_HI(irq), h);
+  cprintf("intr %d: lo 0x%x hi 0x%x\n", irq, l, h);
+}