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-rw-r--r--arch/arm/cpu/armv7/omap3/timer.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/omap3/timer.c b/arch/arm/cpu/armv7/omap3/timer.c
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+++ b/arch/arm/cpu/armv7/omap3/timer.c
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+/*
+ * (C) Copyright 2008
+ * Texas Instruments
+ *
+ * Richard Woodruff <r-woodruff2@ti.com>
+ * Syed Moahmmed Khasim <khasim@ti.com>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ * Alex Zuepke <azu@sysgo.de>
+ *
+ * (C) Copyright 2002
+ * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
+ *
+ * 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>
+
+static ulong timestamp;
+static ulong lastinc;
+static struct gptimer *timer_base = (struct gptimer *)CONFIG_SYS_TIMERBASE;
+
+/*
+ * Nothing really to do with interrupts, just starts up a counter.
+ * We run the counter with 13MHz, divided by 8, resulting in timer
+ * frequency of 1.625MHz. With 32bit counter register, counter
+ * overflows in ~44min
+ */
+
+/* 13MHz / 8 = 1.625MHz */
+#define TIMER_CLOCK (V_SCLK / (2 << CONFIG_SYS_PTV))
+#define TIMER_LOAD_VAL 0xffffffff
+
+int timer_init(void)
+{
+ /* start the counter ticking up, reload value on overflow */
+ writel(TIMER_LOAD_VAL, &timer_base->tldr);
+ /* enable timer */
+ writel((CONFIG_SYS_PTV << 2) | TCLR_PRE | TCLR_AR | TCLR_ST,
+ &timer_base->tclr);
+
+ reset_timer_masked(); /* init the timestamp and lastinc value */
+
+ return 0;
+}
+
+/*
+ * timer without interrupts
+ */
+void reset_timer(void)
+{
+ reset_timer_masked();
+}
+
+ulong get_timer(ulong base)
+{
+ return get_timer_masked() - base;
+}
+
+void set_timer(ulong t)
+{
+ timestamp = t;
+}
+
+/* delay x useconds */
+void __udelay(unsigned long usec)
+{
+ long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
+ unsigned long now, last = readl(&timer_base->tcrr);
+
+ while (tmo > 0) {
+ now = readl(&timer_base->tcrr);
+ if (last > now) /* count up timer overflow */
+ tmo -= TIMER_LOAD_VAL - last + now;
+ else
+ tmo -= now - last;
+ last = now;
+ }
+}
+
+void reset_timer_masked(void)
+{
+ /* reset time, capture current incrementer value time */
+ lastinc = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
+ timestamp = 0; /* start "advancing" time stamp from 0 */
+}
+
+ulong get_timer_masked(void)
+{
+ /* current tick value */
+ ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
+
+ if (now >= lastinc) /* normal mode (non roll) */
+ /* move stamp fordward with absoulte diff ticks */
+ timestamp += (now - lastinc);
+ else /* we have rollover of incrementer */
+ timestamp += ((TIMER_LOAD_VAL / (TIMER_CLOCK / CONFIG_SYS_HZ))
+ - lastinc) + now;
+ lastinc = now;
+ return timestamp;
+}
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+unsigned long long get_ticks(void)
+{
+ return get_timer(0);
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+ulong get_tbclk(void)
+{
+ return CONFIG_SYS_HZ;
+}