1 files changed, 79 insertions, 0 deletions
diff --git a/arch/arm/cpu/arm926ejs/nomadik/timer.c b/arch/arm/cpu/arm926ejs/nomadik/timer.c
new file mode 100644
index 0000000..1d98ef3
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/nomadik/timer.c
@@ -0,0 +1,79 @@
+/*
+ * (C) Copyright 2009 Alessandro Rubini
+ *
+ * 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/arch/mtu.h>
+
+/*
+ * The timer is a decrementer, we'll left it free running at 2.4MHz.
+ * We have 2.4 ticks per microsecond and an overflow in almost 30min
+ */
+#define TIMER_CLOCK		(24 * 100 * 1000)
+#define COUNT_TO_USEC(x)	((x) * 5 / 12)	/* overflows at 6min */
+#define USEC_TO_COUNT(x)	((x) * 12 / 5)	/* overflows at 6min */
+#define TICKS_PER_HZ		(TIMER_CLOCK / CONFIG_SYS_HZ)
+#define TICKS_TO_HZ(x)		((x) / TICKS_PER_HZ)
+
+/* macro to read the decrementing 32 bit timer as an increasing count */
+#define READ_TIMER() (0 - readl(CONFIG_SYS_TIMERBASE + MTU_VAL(0)))
+
+/* Configure a free-running, auto-wrap counter with no prescaler */
+int timer_init(void)
+{
+	writel(MTU_CRn_ENA | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS,
+	       CONFIG_SYS_TIMERBASE + MTU_CR(0));
+	reset_timer();
+	return 0;
+}
+
+/* Restart counting from 0 */
+void reset_timer(void)
+{
+	ulong val;
+	writel(0, CONFIG_SYS_TIMERBASE + MTU_LR(0));
+	/*
+	 * The load-register isn't really immediate: it changes on clock
+	 * edges, so we must wait for our newly-written value to appear.
+	 * Since we might miss reading 0, wait for any change in value.
+	 */
+	val = READ_TIMER();
+	while (READ_TIMER() == val)
+		;
+}
+
+/* Return how many HZ passed since "base" */
+ulong get_timer(ulong base)
+{
+	return  TICKS_TO_HZ(READ_TIMER()) - base;
+}
+
+/* Delay x useconds */
+void __udelay(unsigned long usec)
+{
+	ulong ini, end;
+
+	ini = READ_TIMER();
+	end = ini + USEC_TO_COUNT(usec);
+	while ((signed)(end - READ_TIMER()) > 0)
+		;
+}