1 // Helpers for working with i8259 interrupt controller.
3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
4 // Copyright (C) 2002 MandrakeSoft S.A.
6 // This file may be distributed under the terms of the GNU GPLv3 license.
13 dprintf(3, "init pic\n");
14 // Send ICW1 (select OCW1 + will send ICW4)
15 outb(0x11, PORT_PIC1_CMD);
16 outb(0x11, PORT_PIC2_CMD);
17 // Send ICW2 (base irqs: 0x08-0x0f for irq0-7, 0x70-0x78 for irq8-15)
18 outb(0x08, PORT_PIC1_DATA);
19 outb(0x70, PORT_PIC2_DATA);
20 // Send ICW3 (cascaded pic ids)
21 outb(0x04, PORT_PIC1_DATA);
22 outb(0x02, PORT_PIC2_DATA);
23 // Send ICW4 (enable 8086 mode)
24 outb(0x01, PORT_PIC1_DATA);
25 outb(0x01, PORT_PIC2_DATA);
26 // Mask all irqs (except cascaded PIC2 irq)
27 outb(~PIC1_IRQ2, PORT_PIC1_DATA);
28 outb(~0, PORT_PIC2_DATA);
31 // Handler for otherwise unused hardware irqs.
33 handle_hwirq(struct bregs *regs)
35 debug_isr(DEBUG_ISR_hwirq);
37 u8 isr1 = get_pic1_isr();
39 dprintf(1, "Got hwirq with no ISR\n");
43 u8 isr2 = get_pic2_isr();
44 u16 isr = isr2<<8 | isr1;
45 dprintf(1, "Masking noisy irq %x\n", isr);
50 if (! (isr1 & 0x2)) // don't ever mask the cascaded irq