| #include <arch/io.h> |
| /* code taken from: |
| ! |
| ! setup.S Copyright (C) 1991, 1992 Linus Torvalds |
| ! |
| ! setup.s is responsible for getting the system data from the BIOS, |
| ! and putting them into the appropriate places in system memory. |
| ! both setup.s and system has been loaded by the bootblock. |
| */ |
| /* we're getting screwed again and again by this problem of the 8259. |
| * so we're going to leave this lying around for inclusion into |
| * crt0.S on an as-needed basis. |
| ! well, that went ok, I hope. Now we have to reprogram the interrupts :-( |
| ! we put them right after the intel-reserved hardware interrupts, at |
| ! int 0x20-0x2F. There they won't mess up anything. Sadly IBM really |
| ! messed this up with the original PC, and they haven't been able to |
| ! rectify it afterwards. Thus the bios puts interrupts at 0x08-0x0f, |
| ! which is used for the internal hardware interrupts as well. We just |
| ! have to reprogram the 8259's, and it isn't fun. |
| */ |
| |
| void setup_i8259(void) |
| { |
| outb(0x11, 0x20); /*! initialization sequence to 8259A-1*/ |
| outb(0x11, 0xA0); /*! and to 8259A-2*/ |
| outb(0x20, 0x21); /*! start of hardware int's (0x20)*/ |
| outb(0x28, 0xA1); /*! start of hardware int's 2 (0x28)*/ |
| outb(0x04, 0x21); /*! 8259-1 is master*/ |
| outb(0x02, 0xA1); /*! 8259-2 is slave*/ |
| outb(0x01, 0x21); /*! 8086 mode for both*/ |
| outb(0x01, 0xA1); |
| outb(0xFF, 0xA1); /*! mask off all interrupts for now*/ |
| outb(0xFB, 0x21); /*! mask all irq's but irq2 which is cascaded*/ |
| } |
| |
| /* |
| * I like the way Linus says it: |
| ! Well, that certainly wasn't fun :-(. Hopefully it works, and we don't |
| ! need no steenking BIOS anyway (except for the initial loading :-). |
| */ |
| |