u-boot/cpu/arm926ejs/davinci/timer.c
Ingo van Lil 3eb90bad65 Generic udelay() with watchdog support
According to the PPC reference implementation the udelay() function is
responsible for resetting the watchdog timer as frequently as needed.
Most other architectures do not meet that requirement, so long-running
operations might result in a watchdog reset.

This patch adds a generic udelay() function which takes care of
resetting the watchdog before calling an architecture-specific
__udelay().

Signed-off-by: Ingo van Lil <inguin@gmx.de>
2009-12-05 01:08:53 +01:00

149 lines
3.3 KiB
C

/*
* (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>
*
* Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
*
* 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 <asm/io.h>
struct davinci_timer {
u_int32_t pid12;
u_int32_t emumgt;
u_int32_t na1;
u_int32_t na2;
u_int32_t tim12;
u_int32_t tim34;
u_int32_t prd12;
u_int32_t prd34;
u_int32_t tcr;
u_int32_t tgcr;
u_int32_t wdtcr;
};
static struct davinci_timer * const timer =
(struct davinci_timer *)CONFIG_SYS_TIMERBASE;
#define TIMER_LOAD_VAL (CONFIG_SYS_HZ_CLOCK / CONFIG_SYS_HZ)
#define TIM_CLK_DIV 16
static ulong timestamp;
static ulong lastinc;
int timer_init(void)
{
/* We are using timer34 in unchained 32-bit mode, full speed */
writel(0x0, &timer->tcr);
writel(0x0, &timer->tgcr);
writel(0x06 | ((TIM_CLK_DIV - 1) << 8), &timer->tgcr);
writel(0x0, &timer->tim34);
writel(TIMER_LOAD_VAL, &timer->prd34);
lastinc = 0;
timestamp = 0;
writel(2 << 22, &timer->tcr);
return(0);
}
void reset_timer(void)
{
writel(0x0, &timer->tcr);
writel(0x0, &timer->tim34);
lastinc = 0;
timestamp = 0;
writel(2 << 22, &timer->tcr);
}
static ulong get_timer_raw(void)
{
ulong now = readl(&timer->tim34);
if (now >= lastinc) {
/* normal mode */
timestamp += now - lastinc;
} else {
/* overflow ... */
timestamp += now + TIMER_LOAD_VAL - lastinc;
}
lastinc = now;
return timestamp;
}
ulong get_timer(ulong base)
{
return((get_timer_raw() / (TIMER_LOAD_VAL / TIM_CLK_DIV)) - base);
}
void set_timer(ulong t)
{
timestamp = t;
}
void __udelay(unsigned long usec)
{
ulong tmo;
ulong endtime;
signed long diff;
tmo = CONFIG_SYS_HZ_CLOCK / 1000;
tmo *= usec;
tmo /= (1000 * TIM_CLK_DIV);
endtime = get_timer_raw() + tmo;
do {
ulong 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;
}