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u-boot/arch/arm/mach-at91/arm920t/timer.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2002
* Lineo, Inc. <www.lineo.com>
* Bernhard Kuhn <bkuhn@lineo.com>
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroeger@sysgo.de>
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Alex Zuepke <azu@sysgo.de>
*/
#include <common.h>
#include <init.h>
#include <time.h>
#include <asm/global_data.h>
#include <linux/delay.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>
#include <asm/arch/at91_tc.h>
#include <asm/arch/clk.h>
DECLARE_GLOBAL_DATA_PTR;
/* the number of clocks per CONFIG_SYS_HZ */
#define TIMER_LOAD_VAL (CFG_SYS_HZ_CLOCK/CONFIG_SYS_HZ)
int timer_init(void)
{
at91_tc_t *tc = (at91_tc_t *) ATMEL_BASE_TC;
at91_periph_clk_enable(ATMEL_ID_TC0);
writel(0, &tc->bcr);
writel(AT91_TC_BMR_TC0XC0S_NONE | AT91_TC_BMR_TC1XC1S_NONE |
AT91_TC_BMR_TC2XC2S_NONE , &tc->bmr);
writel(AT91_TC_CCR_CLKDIS, &tc->tc[0].ccr);
/* set to MCLK/2 and restart the timer
when the value in TC_RC is reached */
writel(AT91_TC_CMR_TCCLKS_CLOCK1 | AT91_TC_CMR_CPCTRG, &tc->tc[0].cmr);
writel(0xFFFFFFFF, &tc->tc[0].idr); /* disable interrupts */
writel(TIMER_LOAD_VAL, &tc->tc[0].rc);
writel(AT91_TC_CCR_SWTRG | AT91_TC_CCR_CLKEN, &tc->tc[0].ccr);
gd->arch.lastinc = 0;
gd->arch.tbl = 0;
return 0;
}
/*
* timer without interrupts
*/
ulong get_timer_raw(void)
{
at91_tc_t *tc = (at91_tc_t *) ATMEL_BASE_TC;
u32 now;
now = readl(&tc->tc[0].cv) & 0x0000ffff;
if (now >= gd->arch.lastinc) {
/* normal mode */
gd->arch.tbl += now - gd->arch.lastinc;
} else {
/* we have an overflow ... */
gd->arch.tbl += now + TIMER_LOAD_VAL - gd->arch.lastinc;
}
gd->arch.lastinc = now;
return gd->arch.tbl;
}
static ulong get_timer_masked(void)
{
return get_timer_raw()/TIMER_LOAD_VAL;
}
ulong get_timer(ulong base)
{
return get_timer_masked() - base;
}
void __udelay(unsigned long usec)
{
u32 tmo;
u32 endtime;
signed long diff;
tmo = CFG_SYS_HZ_CLOCK / 1000;
tmo *= usec;
tmo /= 1000;
endtime = get_timer_raw() + tmo;
do {
u32 now = get_timer_raw();
diff = endtime - now;
} while (diff >= 0);
}
/*
* This function is derived from PowerPC code (read timebase as long long).
* On ARM it just returns the timer value.
*/
unsigned long long get_ticks(void)
{
return get_timer(0);
}
/*
* 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)
{
return CONFIG_SYS_HZ;
}