[prefix] Add A20-enabling code in libflat

[gpxe.git] / src / arch / i386 / firmware / pcbios / gateA20.c

diff --git a/src/arch/i386/firmware/pcbios/gateA20.c b/src/arch/i386/firmware/pcbios/gateA20.c
index 2caac89..1a71472 100644 (file)
--- a/src/arch/i386/firmware/pcbios/gateA20.c
+++ b/src/arch/i386/firmware/pcbios/gateA20.c
@@ -1,6 +1,9 @@
+FILE_LICENCE ( GPL2_OR_LATER );
+
 #include <stdio.h>
 #include <realmode.h>
 #include <bios.h>
+#include <gpxe/io.h>
 #include <gpxe/timer.h>
 
 #define K_RDWR         0x60            /* keyboard data & cmds (read/write) */
@@ -12,6 +15,7 @@
 
 #define KC_CMD_WIN     0xd0            /* read  output port */
 #define KC_CMD_WOUT    0xd1            /* write output port */
+#define KC_CMD_NULL    0xff            /* null command ("pulse nothing") */
 #define KB_SET_A20     0xdf            /* enable A20,
                                           enable output buffer full interrupt
                                           enable data line
@@ -47,9 +51,9 @@ static void empty_8042 ( void ) {
        time = currticks() + TICKS_PER_SEC;     /* max wait of 1 second */
        while ( ( inb ( K_CMD ) & ( K_IBUF_FUL | K_OBUF_FUL ) ) &&
                currticks() < time ) {
-               SLOW_DOWN_IO;
-               ( void ) inb ( K_RDWR );
-               SLOW_DOWN_IO;
+               iodelay();
+               ( void ) inb_p ( K_RDWR );
+               iodelay();
        }
 }
 
@@ -76,7 +80,7 @@ static int gateA20_is_set ( int retries ) {
                /* Avoid false negatives */
                test_pattern++;
 
-               SLOW_DOWN_IO;
+               iodelay();
 
                /* Always retry at least once, to avoid false negatives */
        } while ( retries-- >= 0 );
@@ -130,6 +134,8 @@ void gateA20_set ( void ) {
                        empty_8042();
                        outb ( KB_SET_A20, K_RDWR );
                        empty_8042();
+                       outb ( KC_CMD_NULL, K_CMD );
+                       empty_8042();
                        if ( gateA20_is_set ( A20_KBC_RETRIES ) ) {
                                DBG ( "Enabled gate A20 using "
                                      "keyboard controller\n" );
@@ -142,9 +148,9 @@ void gateA20_set ( void ) {
                        scp_a = inb ( SCP_A );
                        scp_a &= ~0x01; /* Avoid triggering a reset */
                        scp_a |= 0x02; /* Enable A20 */
-                       SLOW_DOWN_IO;
+                       iodelay();
                        outb ( scp_a, SCP_A );
-                       SLOW_DOWN_IO;
+                       iodelay();
                        if ( gateA20_is_set ( A20_SCPA_RETRIES ) ) {
                                DBG ( "Enabled gate A20 using "
                                      "Fast Gate A20\n" );