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/*
* (C) Copyright 2007-2008
* 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
*/
#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 <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 *) 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);
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 *) ATMEL_BASE_PIT;
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 start;
ulong tmo;
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 tick_to_time(get_ticks()) - base;
}
/*
* Return the number of timer ticks per second.
*/
ulong get_tbclk(void)
{
return gd->timer_rate_hz;
}
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