u-boot/arch/arm/mach-versatile/timer.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2003
* Texas Instruments <www.ti.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>
*
* (C) Copyright 2002-2004
* Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
*
* (C) Copyright 2004
* Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
*/
#include <common.h>
#define TIMER_ENABLE (1 << 7)
#define TIMER_MODE_MSK (1 << 6)
#define TIMER_MODE_FR (0 << 6)
#define TIMER_MODE_PD (1 << 6)
#define TIMER_INT_EN (1 << 5)
#define TIMER_PRS_MSK (3 << 2)
#define TIMER_PRS_8S (1 << 3)
#define TIMER_SIZE_MSK (1 << 2)
#define TIMER_ONE_SHT (1 << 0)
int timer_init (void)
{
ulong tmr_ctrl_val;
/* 1st disable the Timer */
tmr_ctrl_val = *(volatile ulong *)(CFG_SYS_TIMERBASE + 8);
tmr_ctrl_val &= ~TIMER_ENABLE;
*(volatile ulong *)(CFG_SYS_TIMERBASE + 8) = tmr_ctrl_val;
/*
* The Timer Control Register has one Undefined/Shouldn't Use Bit
* So we should do read/modify/write Operation
*/
/*
* Timer Mode : Free Running
* Interrupt : Disabled
* Prescale : 8 Stage, Clk/256
* Tmr Siz : 16 Bit Counter
* Tmr in Wrapping Mode
*/
tmr_ctrl_val = *(volatile ulong *)(CFG_SYS_TIMERBASE + 8);
tmr_ctrl_val &= ~(TIMER_MODE_MSK | TIMER_INT_EN | TIMER_PRS_MSK | TIMER_SIZE_MSK | TIMER_ONE_SHT );
tmr_ctrl_val |= (TIMER_ENABLE | TIMER_PRS_8S);
*(volatile ulong *)(CFG_SYS_TIMERBASE + 8) = tmr_ctrl_val;
return 0;
}