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-rw-r--r--cpu/arm1136/mx31/timer.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/cpu/arm1136/mx31/timer.c b/cpu/arm1136/mx31/timer.c
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+++ b/cpu/arm1136/mx31/timer.c
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+/*
+ * (C) Copyright 2007
+ * Sascha Hauer, Pengutronix
+ *
+ * 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/arch/mx31-regs.h>
+#include <div64.h>
+
+#define TIMER_BASE 0x53f90000 /* General purpose timer 1 */
+
+/* General purpose timers registers */
+#define GPTCR __REG(TIMER_BASE) /* Control register */
+#define GPTPR __REG(TIMER_BASE + 0x4) /* Prescaler register */
+#define GPTSR __REG(TIMER_BASE + 0x8) /* Status register */
+#define GPTCNT __REG(TIMER_BASE + 0x24) /* Counter register */
+
+/* General purpose timers bitfields */
+#define GPTCR_SWR (1 << 15) /* Software reset */
+#define GPTCR_FRR (1 << 9) /* Freerun / restart */
+#define GPTCR_CLKSOURCE_32 (4 << 6) /* Clock source */
+#define GPTCR_TEN 1 /* Timer enable */
+
+static ulong timestamp;
+static ulong lastinc;
+
+/* "time" is measured in 1 / CONFIG_SYS_HZ seconds, "tick" is internal timer period */
+#ifdef CONFIG_MX31_TIMER_HIGH_PRECISION
+/* ~0.4% error - measured with stop-watch on 100s boot-delay */
+static inline unsigned long long tick_to_time(unsigned long long tick)
+{
+ tick *= CONFIG_SYS_HZ;
+ do_div(tick, CONFIG_MX31_CLK32);
+ return tick;
+}
+
+static inline unsigned long long time_to_tick(unsigned long long time)
+{
+ time *= CONFIG_MX31_CLK32;
+ do_div(time, CONFIG_SYS_HZ);
+ return time;
+}
+
+static inline unsigned long long us_to_tick(unsigned long long us)
+{
+ us = us * CONFIG_MX31_CLK32 + 999999;
+ do_div(us, 1000000);
+ return us;
+}
+#else
+/* ~2% error */
+#define TICK_PER_TIME ((CONFIG_MX31_CLK32 + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ)
+#define US_PER_TICK (1000000 / CONFIG_MX31_CLK32)
+
+static inline unsigned long long tick_to_time(unsigned long long tick)
+{
+ do_div(tick, TICK_PER_TIME);
+ return tick;
+}
+
+static inline unsigned long long time_to_tick(unsigned long long time)
+{
+ return time * TICK_PER_TIME;
+}
+
+static inline unsigned long long us_to_tick(unsigned long long us)
+{
+ us += US_PER_TICK - 1;
+ do_div(us, US_PER_TICK);
+ return us;
+}
+#endif
+
+/* The 32768Hz 32-bit timer overruns in 131072 seconds */
+int timer_init (void)
+{
+ int i;
+
+ /* setup GP Timer 1 */
+ GPTCR = GPTCR_SWR;
+ for (i = 0; i < 100; i++)
+ GPTCR = 0; /* We have no udelay by now */
+ GPTPR = 0; /* 32Khz */
+ /* Freerun Mode, PERCLK1 input */
+ GPTCR |= GPTCR_CLKSOURCE_32 | GPTCR_TEN;
+
+ return 0;
+}
+
+void reset_timer_masked (void)
+{
+ /* reset time */
+ lastinc = GPTCNT; /* capture current incrementer value time */
+ timestamp = 0; /* start "advancing" time stamp from 0 */
+}
+
+void reset_timer(void)
+{
+ reset_timer_masked();
+}
+
+unsigned long long get_ticks (void)
+{
+ ulong now = GPTCNT; /* current tick value */
+
+ if (now >= lastinc) /* normal mode (non roll) */
+ /* move stamp forward with absolut diff ticks */
+ timestamp += (now - lastinc);
+ else /* we have rollover of incrementer */
+ timestamp += (0xFFFFFFFF - lastinc) + now;
+ lastinc = now;
+ return timestamp;
+}
+
+ulong get_timer_masked (void)
+{
+ /*
+ * get_ticks() returns a long long (64 bit), it wraps in
+ * 2^64 / CONFIG_MX31_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
+ * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in
+ * 5 * 10^6 days - long enough.
+ */
+ return tick_to_time(get_ticks());
+}
+
+ulong get_timer (ulong base)
+{
+ return get_timer_masked () - base;
+}
+
+void set_timer (ulong t)
+{
+ timestamp = time_to_tick(t);
+}
+
+/* delay x useconds AND perserve advance timstamp value */
+void udelay (unsigned long usec)
+{
+ unsigned long long tmp;
+ ulong tmo;
+
+ tmo = us_to_tick(usec);
+ tmp = get_ticks() + tmo; /* get current timestamp */
+
+ while (get_ticks() < tmp) /* loop till event */
+ /*NOP*/;
+}
+
+void reset_cpu (ulong addr)
+{
+ __REG16(WDOG_BASE) = 4;
+}