u-boot/arch/arm/cpu/arm1136/mx31/timer.c

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/*
* (C) Copyright 2007
* Sascha Hauer, Pengutronix
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/arch/imx-regs.h>
#include <asm/io.h>
#define TIMER_BASE 0x53f90000 /* General purpose timer 1 */
/* General purpose timers registers */
#define GPTCR __REG(TIMER_BASE) /* Control register */
#define GPTPR __REG(TIMER_BASE + 0x4) /* Prescaler register */
#define GPTSR __REG(TIMER_BASE + 0x8) /* Status register */
#define GPTCNT __REG(TIMER_BASE + 0x24) /* Counter register */
/* General purpose timers bitfields */
#define GPTCR_SWR (1 << 15) /* Software reset */
#define GPTCR_FRR (1 << 9) /* Freerun / restart */
#define GPTCR_CLKSOURCE_32 (4 << 6) /* Clock source */
#define GPTCR_TEN 1 /* Timer enable */
DECLARE_GLOBAL_DATA_PTR;
/* The 32768Hz 32-bit timer overruns in 131072 seconds */
int timer_init(void)
{
int i;
/* setup GP Timer 1 */
GPTCR = GPTCR_SWR;
for (i = 0; i < 100; i++)
GPTCR = 0; /* We have no udelay by now */
GPTPR = 0; /* 32Khz */
/* Freerun Mode, PERCLK1 input */
GPTCR |= GPTCR_CLKSOURCE_32 | GPTCR_TEN;
return 0;
}
unsigned long timer_read_counter(void)
{
return GPTCNT;
}