u-boot/arch/powerpc/lib/time.c

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/*
* (C) Copyright 2000, 2001
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* SPDX-License-Identifier: GPL-2.0+
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*/
#include <common.h>
/* ------------------------------------------------------------------------- */
/*
* This function is intended for SHORT delays only.
* It will overflow at around 10 seconds @ 400MHz,
* or 20 seconds @ 200MHz.
*/
unsigned long usec2ticks(unsigned long usec)
{
ulong ticks;
if (usec < 1000) {
ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
} else {
ticks = ((usec / 10) * (get_tbclk() / 100000));
}
return (ticks);
}
/* ------------------------------------------------------------------------- */
/*
* We implement the delay by converting the delay (the number of
* microseconds to wait) into a number of time base ticks; then we
* watch the time base until it has incremented by that amount.
*/
void __udelay(unsigned long usec)
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{
ulong ticks = usec2ticks (usec);
wait_ticks (ticks);
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}
/* ------------------------------------------------------------------------- */
#ifndef CONFIG_NAND_SPL
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unsigned long ticks2usec(unsigned long ticks)
{
ulong tbclk = get_tbclk();
/* usec = ticks * 1000000 / tbclk
* Multiplication would overflow at ~4.2e3 ticks,
* so we break it up into
* usec = ( ( ticks * 1000) / tbclk ) * 1000;
*/
ticks *= 1000L;
ticks /= tbclk;
ticks *= 1000L;
return ((ulong)ticks);
}
#endif
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/* ------------------------------------------------------------------------- */
int init_timebase (void)
{
unsigned long temp;
#if defined(CONFIG_5xx) || defined(CONFIG_8xx)
volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
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/* unlock */
immap->im_sitk.sitk_tbk = KAPWR_KEY;
#endif
/* reset */
asm volatile("li %0,0 ; mttbu %0 ; mttbl %0;"
: "=&r"(temp) );
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#if defined(CONFIG_5xx) || defined(CONFIG_8xx)
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/* enable */
immap->im_sit.sit_tbscr |= TBSCR_TBE;
#endif
return (0);
}
/* ------------------------------------------------------------------------- */