xv6/ioapic.c
kaashoek f70172129c run without lapic and ioapic, if they are not present
if no lapic available, use 8253pit for clock
now xv6 runs both on qemu (uniprocessor) and bochs (uniprocessor and MP)
2006-09-07 01:37:58 +00:00

83 lines
2.1 KiB
C

#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;
if (ismp) {
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)
cprintf("ioapic_init: id isn't equal to ioapic_id; not a MP\n");
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
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);
}
}
}
void
ioapic_enable (int irq, int cpunum)
{
uint l, h;
struct ioapic *io;
if (ismp) {
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 |= (cpunum << APIC_ID_SHIFT);
ioapic_write(io, IOAPIC_REDTBL_HI(irq), h);
}
}