Implement SC520 timers

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

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))

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);
 }

cpu/i386/timer.c

@@ -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

include/asm-i386/u-boot-i386.h

@@ -43,6 +43,13 @@ extern ulong i386boot_bios_size;    /* size of BIOS emulation code */
 
 /* cpu/.../cpu.c */
 int cpu_init(void);
+
+/* cpu/.../timer.c */
+void timer_isr(void *);
+typedef void (timer_fnc_t) (void);
+int register_timer_isr (timer_fnc_t *isr_func);
+
+/* Architecture specific - can be in cpu/i386/, lib_i386/, or $(BOARD)/ */
 int timer_init(void);
 
 /* cpu/.../interrupts.c */

lib_i386/Makefile

@@ -39,7 +39,9 @@ COBJS-y	+= video_bios.o
 COBJS-y	+= video.o
 COBJS-y	+= zimage.o
 COBJS-y	+= interrupts.o
+COBJS-y	+= timer.o
 COBJS-$(CONFIG_SYS_PCAT_INTERRUPTS) += pcat_interrupts.o
+COBJS-$(CONFIG_SYS_GENERIC_TIMER) += pcat_timer.o
 
 SRCS	:= $(SOBJS-y:.o=.S) $(COBJS-y:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS-y) $(COBJS-y))

lib_i386/pcat_timer.c

@@ -0,0 +1,102 @@
+/*
+ * (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>
+
+#define TIMER0_VALUE 0x04aa /* 1kHz 1.9318MHz / 1000 */
+#define TIMER2_VALUE 0x0a8e /* 440Hz */
+
+int timer_init(void)
+{
+	/* 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);
+
+	irq_install_handler (0, timer_isr, NULL);
+	unmask_irq (0);
+
+	return 0;
+}
+
+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)
+	{
+		counter = read_pit ();
+		wraps = usec / 1000;
+		usec = usec % 1000;
+
+		usec *= 1194;
+		usec /= 1000;
+		usec += counter;
+
+		while (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;
+		}
+	}
+
+}

lib_i386/timer.c

@@ -0,0 +1,107 @@
+/*
+ * (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 <malloc.h>
+#include <asm/io.h>
+#include <asm/i8254.h>
+#include <asm/ibmpc.h>
+
+struct timer_isr_function {
+	struct timer_isr_function *next;
+	timer_fnc_t *isr_func;
+};
+
+static struct timer_isr_function *first_timer_isr = NULL;
+static volatile unsigned long system_ticks = 0;
+
+/*
+ * register_timer_isr() allows multiple architecture and board specific
+ * functions to be called every millisecond. Keep the execution time of
+ * each function as low as possible
+ */
+int register_timer_isr (timer_fnc_t *isr_func)
+{
+	struct timer_isr_function *new_func;
+	struct timer_isr_function *temp;
+	int flag;
+
+	new_func = malloc(sizeof(struct timer_isr_function));
+
+	if (new_func == NULL)
+		return 1;
+
+	new_func->isr_func = isr_func;
+	new_func->next = NULL;
+
+	/*
+	 *  Don't allow timer interrupts while the
+	 *  linked list is being modified
+	 */
+	flag = disable_interrupts ();
+
+	if (first_timer_isr == NULL) {
+		first_timer_isr = new_func;
+	} else {
+		temp = first_timer_isr;
+		while (temp->next != NULL)
+			temp = temp->next;
+		temp->next = new_func;
+	}
+
+	if (flag)
+		enable_interrupts ();
+
+	return 0;
+}
+
+/*
+ * timer_isr() MUST be the registered interrupt handler for
+ */
+void timer_isr(void *unused)
+{
+	struct timer_isr_function *temp = first_timer_isr;
+
+	system_ticks++;
+
+	/* Execute each registered function */
+	while (temp != NULL) {
+		temp->isr_func ();
+		temp = temp->next;
+	}
+}
+
+void reset_timer (void)
+{
+	system_ticks = 0;
+}
+
+ulong get_timer (ulong base)
+{
+	return (system_ticks - base);
+}
+
+void set_timer (ulong t)
+{
+	system_ticks = t;
+}