* Patch by Daniel Engström, 13 Nov 2002:

  Add support for i386 architecture and AMD SC520 board

* Patch by Pierre Aubert, 12 Nov 2002:
  Add support for DOS filesystem and booting from DOS floppy disk

1 files changed, 211 insertions, 0 deletions

diff --git a/cpu/i386/timer.c b/cpu/i386/timer.c
new file mode 100644
index 0000000..a23cd6e
--- /dev/null
+++ b/cpu/i386/timer.c
@@ -0,0 +1,211 @@
+/*
+ * (C) Copyright 2002
+ * Daniel Engström, Omicron Ceti AB, daniel@omicron.se.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/i8254.h>
+#include <asm/ibmpc.h>
+
+
+static volatile unsigned long system_ticks;
+static int timer_init_done =0;
+
+static void timer_isr(void *unused)
+{
+	system_ticks++;
+}
+
+unsigned long get_system_ticks(void)
+{
+	return system_ticks;
+}
+
+#define TIMER0_VALUE 0x04aa /* 1kHz 1.9318MHz / 1000 */
+#define TIMER2_VALUE 0x0a8e /* 440Hz */
+
+int timer_init(void)
+{
+	system_ticks = 0;
+	
+	irq_install_handler(0, timer_isr, NULL);
+	
+	/* initialize timer 0 and 2 
+	 * 
+	 * Timer 0 is used to increment system_tick 1000 times/sec
+	 * Timer 1 was used for DRAM refresh in early PC's
+	 * Timer 2 is used to drive the speaker
+	 * (to stasrt a beep: write 3 to port 0x61,
+	 * to stop it again: write 0)
+	 */
+		
+        outb(PIT_CMD_CTR0|PIT_CMD_BOTH|PIT_CMD_MODE2, PIT_BASE + PIT_COMMAND);
+	outb(TIMER0_VALUE&0xff, PIT_BASE + PIT_T0);
+	outb(TIMER0_VALUE>>8, PIT_BASE + PIT_T0);
+
+        outb(PIT_CMD_CTR2|PIT_CMD_BOTH|PIT_CMD_MODE3, PIT_BASE + PIT_COMMAND);
+	outb(TIMER2_VALUE&0xff, PIT_BASE + PIT_T2);
+	outb(TIMER2_VALUE>>8, PIT_BASE + PIT_T2);
+
+	timer_init_done = 1;
+	
+	return 0;
+}
+
+
+#ifdef CFG_TIMER_GENERIC
+
+/* the unit for these is CFG_HZ */
+
+/* FixMe: implement these */
+void reset_timer (void)
+{
+	system_ticks = 0;
+}
+
+ulong get_timer (ulong base)
+{
+	return (system_ticks - base);
+}
+
+void set_timer (ulong t)	
+{
+	system_ticks = t;
+}
+
+static u16 read_pit(void)
+{
+	u8 low;
+	outb(PIT_CMD_LATCH, PIT_BASE + PIT_COMMAND);
+	low = inb(PIT_BASE + PIT_T0);
+	return ((inb(PIT_BASE + PIT_T0) << 8) | low);
+}
+
+/* this is not very exact */
+void udelay (unsigned long usec)
+{	
+	int counter;
+	int wraps;
+	
+	if (!timer_init_done) {
+		return;
+	}
+	counter = read_pit();
+	wraps = usec/1000;
+	usec = usec%1000;
+	
+	usec*=1194;
+	usec/=1000;
+	usec+=counter; 
+	if (usec > 1194) {
+		usec-=1194;
+		wraps++;
+	}
+
+	while (1) {
+		int new_count = read_pit();
+		
+		if (((new_count < usec) && !wraps) || wraps < 0) {
+			break;
+		}
+		
+		if (new_count > counter) {
+			wraps--;
+		}
+		counter = new_count;
+	}
+	
+}
+
+#if 0
+/* this is a version with debug output */
+void _udelay (unsigned long usec)
+{	
+	int counter;
+	int wraps;
+	
+	int usec1, usec2, usec3;
+	int wraps1, wraps2, wraps3, wraps4;
+	int ctr1, ctr2, ctr3, nct1, nct2;
+	int i;
+	usec1=usec;
+	if (!timer_init_done) {
+		return;
+	}
+	counter = read_pit();
+	ctr1 = counter;
+	wraps = usec/1000;
+	usec = usec%1000;
+	
+	usec2 = usec;
+	wraps1 = wraps;
+	
+	usec*=1194;
+	usec/=1000;
+	usec+=counter; 
+	if (usec > 1194) {
+		usec-=1194;
+		wraps++;
+	}
+
+	usec3 = usec;
+	wraps2 = wraps;
+	
+	ctr2 = wraps3 = nct1 = 4711;
+	ctr3 = wraps4 = nct2 = 4711;
+	i=0;
+	while (1) {
+		int new_count = read_pit();
+		i++;
+		if ((new_count < usec && !wraps) || wraps < 0) {
+			break;
+		}
+		
+		if (new_count > counter) {
+			wraps--;
+		}
+		if (ctr2==4711) {
+			ctr2 = counter;
+			wraps3 = wraps;
+			nct1 = new_count;
+		} else {
+			ctr3 = counter;
+			wraps4 = wraps;
+			nct2 = new_count;
+		}
+		
+		counter = new_count;
+	}
+	
+	printf("udelay(%d)\n", usec1);
+	printf("counter %d\n", ctr1);
+	printf("1: wraps %d, usec %d\n", wraps1, usec2);
+	printf("2: wraps %d, usec %d\n", wraps2, usec3);
+	printf("new_count[0] %d counter %d wraps %d\n", nct1, ctr2, wraps3);
+	printf("new_count[%d] %d counter %d wraps %d\n", i, nct2, ctr3, wraps4);
+
+	printf("%d %d %d %d %d\n",
+	       read_pit(), read_pit(), read_pit(),
+	       read_pit(), read_pit());
+}
+#endif
+#endif