historical/m0-applesillicon.git/xnu-qemu-arm64-5.1.0/roms/u-boot/arch/powerpc/lib/time.c
2024-01-16 11:20:27 -06:00

73 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2000, 2001
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*/
#include <common.h>
#include <asm/io.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)
{
ulong ticks = usec2ticks (usec);
wait_ticks (ticks);
}
/* ------------------------------------------------------------------------- */
#ifndef CONFIG_NAND_SPL
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
/* ------------------------------------------------------------------------- */
int timer_init(void)
{
unsigned long temp;
/* reset */
asm volatile("li %0,0 ; mttbl %0 ; mttbu %0;"
: "=&r"(temp) );
return (0);
}
/* ------------------------------------------------------------------------- */