u-boot/arch/arm/cpu/arm926ejs/mb86r0x/timer.c

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/*
* (C) Copyright 2007-2008
* Stelian Pop <stelian@popies.net>
* Lead Tech Design <www.leadtechdesign.com>
*
* (C) Copyright 2010
* Matthias Weisser, Graf-Syteco <weisserm@arcor.de>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <div64.h>
#include <common.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>
#define TIMER_LOAD_VAL 0xffffffff
#define TIMER_FREQ (CONFIG_MB86R0x_IOCLK / 256)
DECLARE_GLOBAL_DATA_PTR;
#define timestamp gd->arch.tbl
#define lastdec gd->arch.lastinc
static inline unsigned long long tick_to_time(unsigned long long tick)
{
tick *= CONFIG_SYS_HZ;
do_div(tick, TIMER_FREQ);
return tick;
}
static inline unsigned long long usec_to_tick(unsigned long long usec)
{
usec *= TIMER_FREQ;
do_div(usec, 1000000);
return usec;
}
/* nothing really to do with interrupts, just starts up a counter. */
int timer_init(void)
{
struct mb86r0x_timer * timer = (struct mb86r0x_timer *)
MB86R0x_TIMER_BASE;
ulong ctrl = readl(&timer->control);
writel(TIMER_LOAD_VAL, &timer->load);
ctrl |= MB86R0x_TIMER_ENABLE | MB86R0x_TIMER_PRS_8S |
MB86R0x_TIMER_SIZE_32;
writel(ctrl, &timer->control);
/* capture current value time */
lastdec = readl(&timer->value);
timestamp = 0; /* start "advancing" time stamp from 0 */
return 0;
}
/*
* timer without interrupts
*/
unsigned long long get_ticks(void)
{
struct mb86r0x_timer * timer = (struct mb86r0x_timer *)
MB86R0x_TIMER_BASE;
ulong now = readl(&timer->value);
if (now <= lastdec) {
/* normal mode (non roll) */
/* move stamp forward with absolut diff ticks */
timestamp += lastdec - now;
} else {
/* we have rollover of incrementer */
timestamp += lastdec + TIMER_LOAD_VAL - now;
}
lastdec = now;
return timestamp;
}
ulong get_timer_masked(void)
{
return tick_to_time(get_ticks());
}
void __udelay(unsigned long usec)
{
unsigned long long tmp;
ulong tmo;
tmo = usec_to_tick(usec);
tmp = get_ticks(); /* get current timestamp */
while ((get_ticks() - tmp) < tmo) /* loop till event */
/*NOP*/;
}
ulong get_timer(ulong base)
{
return get_timer_masked() - base;
}
/*
* 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)
{
ulong tbclk;
tbclk = TIMER_FREQ;
return tbclk;
}