/*
* (C) Copyright 2007-2008
- * Stelian Pop <stelian.pop@leadtechdesign.com>
+ * Stelian Pop <stelian@popies.net>
* 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
+ * SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
+#include <asm/io.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 ulong timestamp;
-static ulong lastinc;
-static ulong timer_freq;
+#define TIMER_LOAD_VAL 0xfffff
static inline unsigned long long tick_to_time(unsigned long long tick)
{
tick *= CONFIG_SYS_HZ;
- do_div(tick, timer_freq);
+ do_div(tick, gd->arch.timer_rate_hz);
return tick;
}
static inline unsigned long long usec_to_tick(unsigned long long usec)
{
- usec *= timer_freq;
+ usec *= gd->arch.timer_rate_hz;
do_div(usec, 1000000);
return usec;
}
-/* nothing really to do with interrupts, just starts up a counter. */
+/*
+ * 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
- * The clock is already enabled for system controller in boot
- */
- writel(1 << AT91_ID_SYS, &pmc->pcer);
+ at91_pmc_t *pmc = (at91_pmc_t *) ATMEL_BASE_PMC;
+ at91_pit_t *pit = (at91_pit_t *) ATMEL_BASE_PIT;
+
+ /* Enable PITC Clock */
+ writel(1 << ATMEL_ID_SYS, &pmc->pcer);
/* Enable PITC */
writel(TIMER_LOAD_VAL | AT91_PIT_MR_EN , &pit->mr);
- reset_timer_masked();
-
- timer_freq = get_mck_clk_rate() >> 4;
+ gd->arch.timer_rate_hz = gd->arch.mck_rate_hz / 16;
+ gd->arch.tbu = gd->arch.tbl = 0;
return 0;
}
/*
- * timer without interrupts
+ * Get the current 64 bit timer tick count
*/
unsigned long long get_ticks(void)
{
- at91_pit_t *pit = (at91_pit_t *) AT91_PIT_BASE;
+ at91_pit_t *pit = (at91_pit_t *) ATMEL_BASE_PIT;
ulong now = readl(&pit->piir);
- 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;
-}
-
-void reset_timer_masked(void)
-{
- /* reset time */
- at91_pit_t *pit = (at91_pit_t *) AT91_PIT_BASE;
-
- /* capture current incrementer value time */
- lastinc = readl(&pit->piir);
- timestamp = 0; /* start "advancing" time stamp from 0 */
-}
-
-ulong get_timer_masked(void)
-{
- return tick_to_time(get_ticks());
+ /* increment tbu if tbl has rolled over */
+ if (now < gd->arch.tbl)
+ gd->arch.tbu++;
+ gd->arch.tbl = now;
+ return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
}
void __udelay(unsigned long usec)
{
- unsigned long long tmp;
+ unsigned long long start;
ulong tmo;
- tmo = usec_to_tick(usec);
- tmp = get_ticks() + tmo; /* get current timestamp */
-
- while (get_ticks() < tmp) /* loop till event */
- /*NOP*/;
-}
-
-void reset_timer(void)
-{
- reset_timer_masked();
+ start = get_ticks(); /* get current timestamp */
+ tmo = usec_to_tick(usec); /* convert usecs to ticks */
+ while ((get_ticks() - start) < tmo)
+ ; /* loop till time has passed */
}
+/*
+ * get_timer(base) can be used to check for timeouts or
+ * to measure elasped time relative to an event:
+ *
+ * ulong start_time = get_timer(0) sets start_time to the current
+ * time value.
+ * get_timer(start_time) returns the time elapsed since then.
+ *
+ * The time is used in CONFIG_SYS_HZ units!
+ */
ulong get_timer(ulong base)
{
- return get_timer_masked () - base;
+ return tick_to_time(get_ticks()) - base;
}
/*
- * This function is derived from PowerPC code (timebase clock frequency).
- * On ARM it returns the number of timer ticks per second.
+ * Return the number of timer ticks per second.
*/
ulong get_tbclk(void)
{
- return timer_freq;
+ return gd->arch.timer_rate_hz;
}