1 files changed, 67 insertions, 0 deletions
diff --git a/kernel/src/apic/ioapic.c b/kernel/src/apic/ioapic.c
new file mode 100644
index 0000000..a8c3452
--- /dev/null
+++ b/kernel/src/apic/ioapic.c
@@ -0,0 +1,67 @@
+#include <ioapic.h>
+#include <apic.h>
+#include <paging.h>
+#include <libk/stdio.h>
+
+void ioapic_eoi()
+{
+	*((volatile uint32_t*)((uint64_t)lapic_addr + 0xB0)) = 0;
+}
+
+uint32_t ioapic_read(const uint8_t offset)
+{
+    /* tell IOREGSEL where we want to read from */
+    *(volatile uint32_t*)(uint64_t)ioapic_addr = offset;
+    /* return the data from IOWIN */
+    return *(volatile uint32_t*)((uint64_t)ioapic_addr + 0x10);
+}
+
+void ioapic_write(const uint8_t offset, const uint32_t val)
+{
+    /* tell IOREGSEL where we want to write to */
+    *(volatile uint32_t*)(uint64_t)ioapic_addr = offset;
+    /* write the value to IOWIN */
+    *(volatile uint32_t*)((uint64_t)ioapic_addr + 0x10) = val;
+}
+
+void ioapic_set_irq(uint8_t irq, uint64_t apic_id, uint8_t vector)
+{
+	const uint32_t low_index = (uint32_t)0x10 + irq*2;
+	const uint32_t high_index = (uint32_t)0x10 + irq*2 + 1;
+
+	uint32_t high = ioapic_read((uint8_t)high_index);
+	// set APIC ID
+	high &= (uint32_t)~0xff000000;
+	high |= (uint32_t)apic_id << 24;
+	ioapic_write((uint8_t)high_index, high);
+
+	uint32_t low = ioapic_read((uint8_t)low_index);
+
+	// unmask the IRQ
+	low &= (uint32_t)~(1<<16);
+
+	// set to physical delivery mode
+	low &= (uint32_t)~(1<<11);
+
+	// set to fixed delivery mode
+	low &= (uint32_t)~0x700;
+
+	// set delivery vector
+	low &= (uint32_t)~0xff;
+	low |= vector;
+
+	ioapic_write((uint8_t)low_index, low);
+}
+
+void apic_remap_interrupts()
+{
+	uint8_t bspid = curr_cpu_apic_id();
+
+	map_addr(ioapic_addr, ioapic_addr, FLAG_PRESENT);
+	map_addr(lapic_addr, lapic_addr, FLAG_PRESENT);
+
+	// irq is 2 because of gsi remap
+	ioapic_set_irq(0x2, bspid, 0x20); // timer
+	ioapic_set_irq(0x1, bspid, 0x21); // keyboard
+	__asm__ volatile ("sti;");
+}