Messages in this thread |  | | Date | Fri, 24 Nov 2000 09:23:55 -0700 (MST) | From | Ronald G Minnich <> | Subject | RE: Booting AMD Elan520 without BIOS |
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On Fri, 24 Nov 2000, Joan Bertran wrote:
> I think so, because I've read somewhere the kernel needs interrupts > configured, but as kernel configures i8259 I don't know what is necessary, > the IDT with interrupt service routines ?, sommething special about the chipset ?
I put the following familiar-looking code at the head of linuxbios for mainboards that need to boot 2.2.x. It should look familiar, except of course this is 32-bit gas-compatible code.
#define i8259delay jmp 1f ; 1:
movb $0x11,%al /*! initialization sequence*/ outb %al,$0x20 /*! send it to 8259A-1*/ i8259delay outb %al,$0xA0 /*! and to 8259A-2*/ i8259delay movb $0x20,%al /*! start of hardware int's (0x20)*/ outb %al,$0x21 i8259delay movb $0x28,%al /*! start of hardware int's 2 (0x28)*/ outb %al,$0xA1 i8259delay movb $0x04,%al /*! 8259-1 is master*/ outb %al,$0x21 i8259delay movb $0x02,%al /*! 8259-2 is slave*/ outb %al,$0xA1 i8259delay movb $0x01,%al /*! 8086 mode for both*/ outb %al,$0x21 i8259delay outb %al,$0xA1 i8259delay movb $0xFF,%al /*! mask off all interrupts for now*/ outb %al,$0xA1 i8259delay movb $0xFB,%al /*! mask all irq's but irq2 which*/ outb %al,$0x21 /*! is cascaded*/
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