Implement SC520 timers

Signed-off-by: Graeme Russ <graeme.russ at gmail.com>

3 files changed, 41 insertions, 243 deletions

diff --git a/cpu/i386/Makefile b/cpu/i386/Makefile
index f72cd6e..e98bd3d 100644
--- a/cpu/i386/Makefile
+++ b/cpu/i386/Makefile
@@ -29,7 +29,7 @@ include $(TOPDIR)/config.mk
 LIB	= $(obj)lib$(CPU).a
 
 START	= start.o start16.o resetvec.o
-COBJS	= serial.o interrupts.o exceptions.o cpu.o timer.o
+COBJS	= serial.o interrupts.o exceptions.o cpu.o
 
 SRCS	:= $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS))
diff --git a/cpu/i386/sc520/sc520_timer.c b/cpu/i386/sc520/sc520_timer.c
index 7578511..2cb8656 100644
--- a/cpu/i386/sc520/sc520_timer.c
+++ b/cpu/i386/sc520/sc520_timer.c
@@ -27,47 +27,56 @@
 #include <asm/interrupt.h>
 #include <asm/ic/sc520.h>
 
-void reset_timer(void)
+void sc520_timer_isr(void)
 {
-	write_mmcr_word(SC520_GPTMR0CNT, 0);
-	write_mmcr_word(SC520_GPTMR0CTL, 0x6001);
-
+	/* Ack the GP Timer Interrupt */
+	write_mmcr_byte (SC520_GPTMRSTA, 0x02);
 }
 
-ulong get_timer(ulong base)
+int timer_init(void)
 {
-	/* fixme: 30 or 33 */
-	return	read_mmcr_word(SC520_GPTMR0CNT) / 33;
-}
+	/* Map GP Timer 1 to Master PIC IR0  */
+	write_mmcr_byte (SC520_GPTMR1MAP, 0x01);
 
-void set_timer(ulong t)
-{
-	/* FixMe: use two cascade coupled timers */
-	write_mmcr_word(SC520_GPTMR0CTL, 0x4001);
-	write_mmcr_word(SC520_GPTMR0CNT, t*33);
-	write_mmcr_word(SC520_GPTMR0CTL, 0x6001);
-}
+	/* Disable GP Timers 1 & 2 - Allow configuration writes */
+	write_mmcr_word (SC520_GPTMR1CTL, 0x4000);
+	write_mmcr_word (SC520_GPTMR2CTL, 0x4000);
+
+	/* Reset GP Timers 1 & 2 */
+	write_mmcr_word (SC520_GPTMR1CNT, 0x0000);
+	write_mmcr_word (SC520_GPTMR2CNT, 0x0000);
+
+	/* Setup GP Timer 2 as a 100kHz (10us) prescaler */
+	write_mmcr_word (SC520_GPTMR2MAXCMPA, 83);
+	write_mmcr_word (SC520_GPTMR2CTL, 0xc001);
+
+	/* Setup GP Timer 1 as a 1000 Hz (1ms) interrupt generator */
+	write_mmcr_word (SC520_GPTMR1MAXCMPA, 100);
+	write_mmcr_word (SC520_GPTMR1CTL, 0xe009);
 
+	/* Clear the GP Timers status register */
+	write_mmcr_byte (SC520_GPTMRSTA, 0x07);
+
+	/* Register the SC520 specific timer interrupt handler */
+	register_timer_isr (sc520_timer_isr);
+
+	/* Install interrupt handler for GP Timer 1 */
+	irq_install_handler (0, timer_isr, NULL);
+	unmask_irq (0);
+
+	return 0;
+}
 
 void udelay(unsigned long usec)
 {
-	int m=0;
+	int m = 0;
 	long u;
 
-	read_mmcr_word(SC520_SWTMRMILLI);
-	read_mmcr_word(SC520_SWTMRMICRO);
-
-#if 0
-	/* do not enable this line, udelay is used in the serial driver -> recursion */
-	printf("udelay: %ld m.u %d.%d  tm.tu %d.%d\n", usec, m, u, tm, tu);
-#endif
-	while (1) {
-
-		m += read_mmcr_word(SC520_SWTMRMILLI);
-		u = read_mmcr_word(SC520_SWTMRMICRO) + (m * 1000);
+	read_mmcr_word (SC520_SWTMRMILLI);
+	read_mmcr_word (SC520_SWTMRMICRO);
 
-		if (usec <= u) {
-			break;
-		}
-	}
+	do {
+		m += read_mmcr_word (SC520_SWTMRMILLI);
+		u = read_mmcr_word (SC520_SWTMRMICRO) + (m * 1000);
+	} while (u < usec);
 }
diff --git a/cpu/i386/timer.c b/cpu/i386/timer.c
deleted file mode 100644
index 79039c2..0000000
--- a/cpu/i386/timer.c
+++ /dev/null
@@ -1,211 +0,0 @@
-/*
- * (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 CONFIG_SYS_GENERIC_TIMER
-
-/* the unit for these is CONFIG_SYS_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