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Diffstat (limited to 'u-boot/arch/arm/cpu/arm926ejs/at91/timer.c')
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diff --git a/u-boot/arch/arm/cpu/arm926ejs/at91/timer.c b/u-boot/arch/arm/cpu/arm926ejs/at91/timer.c
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+/*
+ * (C) Copyright 2007-2008
+ * Stelian Pop <stelian.pop@leadtechdesign.com>
+ * Lead Tech Design <www.leadtechdesign.com>
+ *
+ * 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/hardware.h>
+#include <asm/arch/at91_pit.h>
+#include <asm/arch/at91_pmc.h>
+#include <asm/arch/clk.h>
+#include <asm/arch/io.h>
+#include <div64.h>
+
+#if !defined(CONFIG_AT91FAMILY)
+# error You need to define CONFIG_AT91FAMILY in your board config!
+#endif
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * We're using the AT91CAP9/SAM9 PITC in 32 bit mode, by
+ * setting the 20 bit counter period to its maximum (0xfffff).
+ * (See the relevant data sheets to understand that this really works)
+ *
+ * We do also mimic the typical powerpc way of incrementing
+ * two 32 bit registers called tbl and tbu.
+ *
+ * Those registers increment at 1/16 the main clock rate.
+ */
+
+#define TIMER_LOAD_VAL 0xfffff
+
+static inline unsigned long long tick_to_time(unsigned long long tick)
+{
+ tick *= CONFIG_SYS_HZ;
+ do_div(tick, gd->timer_rate_hz);
+
+ return tick;
+}
+
+static inline unsigned long long usec_to_tick(unsigned long long usec)
+{
+ usec *= gd->timer_rate_hz;
+ do_div(usec, 1000000);
+
+ return usec;
+}
+
+/*
+ * Use the PITC in full 32 bit incrementing mode
+ */
+int timer_init(void)
+{
+ at91_pmc_t *pmc = (at91_pmc_t *) AT91_PMC_BASE;
+ at91_pit_t *pit = (at91_pit_t *) AT91_PIT_BASE;
+
+ /* Enable PITC Clock */
+ writel(1 << AT91_ID_SYS, &pmc->pcer);
+
+ /* Enable PITC */
+ writel(TIMER_LOAD_VAL | AT91_PIT_MR_EN , &pit->mr);
+
+ gd->timer_rate_hz = gd->mck_rate_hz / 16;
+ gd->tbu = gd->tbl = 0;
+
+ return 0;
+}
+
+/*
+ * Get the current 64 bit timer tick count
+ */
+unsigned long long get_ticks(void)
+{
+ at91_pit_t *pit = (at91_pit_t *) AT91_PIT_BASE;
+
+ ulong now = readl(&pit->piir);
+
+ /* increment tbu if tbl has rolled over */
+ if (now < gd->tbl)
+ gd->tbu++;
+ gd->tbl = now;
+ return (((unsigned long long)gd->tbu) << 32) | gd->tbl;
+}
+
+void __udelay(unsigned long usec)
+{
+ unsigned long long tmp;
+ ulong tmo;
+
+ tmo = usec_to_tick(usec);
+ tmp = get_ticks() + tmo; /* get current timestamp */
+
+ while (get_ticks() < tmp) /* loop till event */
+ ;
+}
+
+/*
+ * reset_timer() and get_timer(base) are a pair of functions that are used by
+ * some timeout/sleep mechanisms in u-boot.
+ *
+ * reset_timer() marks the current time as epoch and
+ * get_timer(base) works relative to that epoch.
+ *
+ * The time is used in CONFIG_SYS_HZ units!
+ */
+void reset_timer(void)
+{
+ gd->timer_reset_value = get_ticks();
+}
+
+ulong get_timer(ulong base)
+{
+ return tick_to_time(get_ticks() - gd->timer_reset_value) - base;
+}
+
+/*
+ * Return the number of timer ticks per second.
+ */
+ulong get_tbclk(void)
+{
+ return gd->timer_rate_hz;
+}