Home | History | Annotate | Line # | Download | only in lib
gatea20.c revision 1.1 
      1 /*	$NetBSD: gatea20.c,v 1.1 1997/03/14 02:40:32 perry Exp $	*/
      2 
      3 /* extracted from freebsd:sys/i386/boot/biosboot/io.c */
      4 
      5 #include <sys/types.h>
      6 #include <machine/pio.h>
      7 
      8 #include <lib/libsa/stand.h>
      9 
     10 #include "libi386.h"
     11 
     12 #define K_RDWR 		0x60		/* keyboard data & cmds (read/write) */
     13 #define K_STATUS 	0x64		/* keyboard status */
     14 #define K_CMD	 	0x64		/* keybd ctlr command (write-only) */
     15 
     16 #define K_OBUF_FUL 	0x01		/* output buffer full */
     17 #define K_IBUF_FUL 	0x02		/* input buffer full */
     18 
     19 #define KC_CMD_WIN	0xd0		/* read  output port */
     20 #define KC_CMD_WOUT	0xd1		/* write output port */
     21 #define KB_A20		0x9f		/* enable A20,
     22 					   enable output buffer full interrupt
     23 					   enable data line
     24 					   disable clock line */
     25 
     26 /*
     27  * Gate A20 for high memory
     28  */
     29 static unsigned char	x_20 = KB_A20;
     30 void gateA20()
     31 {
     32 #ifdef	IBM_L40
     33 	outb(0x92, 0x2);
     34 #else	IBM_L40
     35 	while (inb(K_STATUS) & K_IBUF_FUL);
     36 	while (inb(K_STATUS) & K_OBUF_FUL)
     37 		(void)inb(K_RDWR);
     38 
     39 	outb(K_CMD, KC_CMD_WOUT);
     40 	while (inb(K_STATUS) & K_IBUF_FUL);
     41 	outb(K_RDWR, x_20);
     42 	while (inb(K_STATUS) & K_IBUF_FUL);
     43 #endif	IBM_L40
     44 }
     45