Implement SC520 timers

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

3 files changed, 211 insertions, 0 deletions

diff --git a/lib_i386/Makefile b/lib_i386/Makefile
index fb4184b367..ec6f236052 100644
--- a/lib_i386/Makefile
+++ b/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))
diff --git a/lib_i386/pcat_timer.c b/lib_i386/pcat_timer.c
new file mode 100644
index 0000000000..e282f649ac
--- /dev/null
+++ b/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;
+		}
+	}
+
+}
diff --git a/lib_i386/timer.c b/lib_i386/timer.c
new file mode 100644
index 0000000000..5cb1f54fb5
--- /dev/null
+++ b/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;
+}