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/*
* Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
*
* (C) Copyright 2008
* Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
*
* (C) Copyright 2004
* Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
*
* (C) Copyright 2002-2004
* Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
*
* (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>
*
* 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 <div64.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>
DECLARE_GLOBAL_DATA_PTR;
struct scu_timer {
u32 load; /* Timer Load Register */
u32 counter; /* Timer Counter Register */
u32 control; /* Timer Control Register */
};
static struct scu_timer *timer_base =
(struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR;
#define SCUTIMER_CONTROL_PRESCALER_MASK 0x0000FF00 /* Prescaler */
#define SCUTIMER_CONTROL_PRESCALER_SHIFT 8
#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK 0x00000002 /* Auto-reload */
#define SCUTIMER_CONTROL_ENABLE_MASK 0x00000001 /* Timer enable */
#define TIMER_LOAD_VAL 0xFFFFFFFF
#define TIMER_PRESCALE 255
#define TIMER_TICK_HZ (CONFIG_CPU_FREQ_HZ / 2 / TIMER_PRESCALE)
int timer_init(void)
{
const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
(TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
SCUTIMER_CONTROL_ENABLE_MASK;
/* Load the timer counter register */
writel(0xFFFFFFFF, &timer_base->counter);
/*
* Start the A9Timer device
* Enable Auto reload mode, Clear prescaler control bits
* Set prescaler value, Enable the decrementer
*/
clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
emask);
/* Reset time */
gd->arch.lastinc = readl(&timer_base->counter) /
(TIMER_TICK_HZ / CONFIG_SYS_HZ);
gd->arch.tbl = 0;
return 0;
}
/*
* This function is derived from PowerPC code (read timebase as long long).
* On ARM it just returns the timer value.
*/
ulong get_timer_masked(void)
{
ulong now;
now = readl(&timer_base->counter) / (TIMER_TICK_HZ / CONFIG_SYS_HZ);
if (gd->arch.lastinc >= now) {
/* Normal mode */
gd->arch.tbl += gd->arch.lastinc - now;
} else {
/* We have an overflow ... */
gd->arch.tbl += gd->arch.lastinc + TIMER_LOAD_VAL - now;
}
gd->arch.lastinc = now;
return gd->arch.tbl;
}
void __udelay(unsigned long usec)
{
u32 countticks;
u32 timeend;
u32 timediff;
u32 timenow;
if (usec == 0)
return;
countticks = (u32) (((unsigned long long) TIMER_TICK_HZ * usec) /
1000000);
/* decrementing timer */
timeend = readl(&timer_base->counter) - countticks;
#if TIMER_LOAD_VAL != 0xFFFFFFFF
/* do not manage multiple overflow */
if (countticks >= TIMER_LOAD_VAL)
countticks = TIMER_LOAD_VAL - 1;
#endif
do {
timenow = readl(&timer_base->counter);
if (timenow >= timeend) {
/* normal case */
timediff = timenow - timeend;
} else {
if ((TIMER_LOAD_VAL - timeend + timenow) <=
countticks) {
/* overflow */
timediff = TIMER_LOAD_VAL - timeend + timenow;
} else {
/* missed the exact match */
break;
}
}
} while (timediff > 0);
}
/* Timer without interrupts */
ulong get_timer(ulong base)
{
return get_timer_masked() - base;
}
/*
* 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;
}
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