1 files changed, 87 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/arch/i386/core/timer2.c b/contrib/syslinux-4.02/gpxe/src/arch/i386/core/timer2.c
new file mode 100644
index 0000000..6e76b2e
--- /dev/null
+++ b/contrib/syslinux-4.02/gpxe/src/arch/i386/core/timer2.c
@@ -0,0 +1,87 @@
+/*
+ * arch/i386/core/i386_timer.c
+ *
+ * Use the "System Timer 2" to implement the udelay callback in
+ * the BIOS timer driver. Also used to calibrate the clock rate
+ * in the RTDSC timer driver.
+ * 
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2, or (at
+ * your option) any later version.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stddef.h>
+#include <gpxe/timer2.h>
+#include <gpxe/io.h>
+
+/* Timers tick over at this rate */
+#define TIMER2_TICKS_PER_SEC	1193180U
+
+/* Parallel Peripheral Controller Port B */
+#define	PPC_PORTB	0x61
+
+/* Meaning of the port bits */
+#define	PPCB_T2OUT	0x20	/* Bit 5 */
+#define	PPCB_SPKR	0x02	/* Bit 1 */
+#define	PPCB_T2GATE	0x01	/* Bit 0 */
+
+/* Ports for the 8254 timer chip */
+#define	TIMER2_PORT	0x42
+#define	TIMER_MODE_PORT	0x43
+
+/* Meaning of the mode bits */
+#define	TIMER0_SEL	0x00
+#define	TIMER1_SEL	0x40
+#define	TIMER2_SEL	0x80
+#define	READBACK_SEL	0xC0
+
+#define	LATCH_COUNT	0x00
+#define	LOBYTE_ACCESS	0x10
+#define	HIBYTE_ACCESS	0x20
+#define	WORD_ACCESS	0x30
+
+#define	MODE0		0x00
+#define	MODE1		0x02
+#define	MODE2		0x04
+#define	MODE3		0x06
+#define	MODE4		0x08
+#define	MODE5		0x0A
+
+#define	BINARY_COUNT	0x00
+#define	BCD_COUNT	0x01
+
+static void load_timer2 ( unsigned int ticks ) {
+	/*
+	 * Now let's take care of PPC channel 2
+	 *
+	 * Set the Gate high, program PPC channel 2 for mode 0,
+	 * (interrupt on terminal count mode), binary count,
+	 * load 5 * LATCH count, (LSB and MSB) to begin countdown.
+	 *
+	 * Note some implementations have a bug where the high bits byte
+	 * of channel 2 is ignored.
+	 */
+	/* Set up the timer gate, turn off the speaker */
+	/* Set the Gate high, disable speaker */
+	outb((inb(PPC_PORTB) & ~PPCB_SPKR) | PPCB_T2GATE, PPC_PORTB);
+	/* binary, mode 0, LSB/MSB, Ch 2 */
+	outb(TIMER2_SEL|WORD_ACCESS|MODE0|BINARY_COUNT, TIMER_MODE_PORT);
+	/* LSB of ticks */
+	outb(ticks & 0xFF, TIMER2_PORT);
+	/* MSB of ticks */
+	outb(ticks >> 8, TIMER2_PORT);
+}
+
+static int timer2_running ( void ) {
+	return ((inb(PPC_PORTB) & PPCB_T2OUT) == 0);
+}
+
+void timer2_udelay ( unsigned long usecs ) {
+	load_timer2 ( ( usecs * TIMER2_TICKS_PER_SEC ) / ( 1000 * 1000 ) );
+	while (timer2_running()) {
+		/* Do nothing */
+	}
+}