1 files changed, 168 insertions, 0 deletions
diff --git a/cpu/arm920t/ep93xx/timer.c b/cpu/arm920t/ep93xx/timer.c
new file mode 100644
index 0000000..6d969d9
--- /dev/null
+++ b/cpu/arm920t/ep93xx/timer.c
@@ -0,0 +1,168 @@
+/*
+ * Cirrus Logic EP93xx timer support.
+ *
+ * Copyright (C) 2009, 2010
+ * Matthias Kaehlcke <matthias@kaehlcke.net>
+ *
+ * Copyright (C) 2004, 2005
+ * Cory T. Tusar, Videon Central, Inc., <ctusar@videon-central.com>
+ *
+ * Based on the original intr.c Cirrus Logic EP93xx Rev D. interrupt support,
+ * author unknown.
+ *
+ * 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.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <common.h>
+#include <linux/types.h>
+#include <asm/arch/ep93xx.h>
+#include <asm/io.h>
+
+#define TIMER_CLKSEL	(1 << 3)
+#define TIMER_MODE	(1 << 6)
+#define TIMER_ENABLE	(1 << 7)
+
+#define TIMER_FREQ	508469
+#define TIMER_LOAD_VAL	(TIMER_FREQ / CONFIG_SYS_HZ)
+
+static ulong timestamp;
+static ulong lastdec;
+
+static inline unsigned long clk_to_systicks(unsigned long clk_ticks)
+{
+	unsigned long sys_ticks = (clk_ticks * CONFIG_SYS_HZ) / TIMER_FREQ;
+
+	return sys_ticks;
+}
+
+static inline unsigned long usecs_to_ticks(unsigned long usecs)
+{
+	unsigned long ticks;
+
+	if (usecs >= 1000) {
+		ticks = usecs / 1000;
+		ticks *= (TIMER_LOAD_VAL * CONFIG_SYS_HZ);
+		ticks /= 1000;
+	} else {
+		ticks = usecs * TIMER_LOAD_VAL * CONFIG_SYS_HZ;
+		ticks /= (1000 * 1000);
+	}
+
+	return ticks;
+}
+
+static inline unsigned long read_timer(void)
+{
+	struct timer_regs *timer = (struct timer_regs *)TIMER_BASE;
+
+	return readl(&timer->timer3.value);
+}
+
+/*
+ * timer without interrupts
+ */
+unsigned long long get_ticks(void)
+{
+	const unsigned long now = read_timer();
+
+	if (lastdec >= now) {
+		/* normal mode */
+		timestamp += lastdec - now;
+	} else {
+		/* we have an overflow ... */
+		timestamp += lastdec + TIMER_LOAD_VAL - now;
+	}
+
+	lastdec = now;
+
+	return timestamp;
+}
+
+unsigned long get_timer_masked(void)
+{
+	return clk_to_systicks(get_ticks());
+}
+
+unsigned long get_timer(unsigned long base)
+{
+	return get_timer_masked() - base;
+}
+
+void reset_timer_masked(void)
+{
+	lastdec = read_timer();
+	timestamp = 0;
+}
+
+void reset_timer(void)
+{
+	reset_timer_masked();
+}
+
+void set_timer(unsigned long t)
+{
+	timestamp = t;
+}
+
+void __udelay(unsigned long usec)
+{
+	const unsigned long ticks = usecs_to_ticks(usec);
+	const unsigned long target = clk_to_systicks(ticks) + get_timer(0);
+
+	while (get_timer_masked() < target)
+		/* noop */;
+}
+
+void udelay_masked(unsigned long usec)
+{
+	const unsigned long ticks = usecs_to_ticks(usec);
+	const unsigned long target = clk_to_systicks(ticks) + get_timer(0);
+
+	reset_timer_masked();
+
+	while (get_timer_masked() < target)
+		/* noop */;
+}
+
+int timer_init(void)
+{
+	struct timer_regs *timer = (struct timer_regs *)TIMER_BASE;
+
+	/* use timer 3 with 508KHz and free running */
+	writel(TIMER_CLKSEL, &timer->timer3.control);
+
+	/* auto load, manual update of Timer 3 */
+	lastdec = TIMER_LOAD_VAL;
+	writel(TIMER_LOAD_VAL, &timer->timer3.load);
+
+	/* Enable the timer and periodic mode */
+	writel(TIMER_ENABLE | TIMER_MODE | TIMER_CLKSEL,
+		&timer->timer3.control);
+
+	reset_timer_masked();
+
+	return 0;
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+unsigned long get_tbclk(void)
+{
+	return CONFIG_SYS_HZ;
+}