linux/arch/s390/lib/delay.c
Heiko Carstens 9aa10e791c s390/delay: sync comment within __delay() with reality
The comment within __delay() is outdated and does not reflect anymore
what the function is doing. Therefore replace the comment.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2022-08-30 22:00:33 +02:00

46 lines
914 B
C

// SPDX-License-Identifier: GPL-2.0
/*
* Precise Delay Loops for S390
*
* Copyright IBM Corp. 1999, 2008
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
*/
#include <linux/processor.h>
#include <linux/delay.h>
#include <asm/div64.h>
#include <asm/timex.h>
void __delay(unsigned long loops)
{
/*
* Loop 'loops' times. Callers must not assume a specific
* amount of time passes before this function returns.
*/
asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
}
EXPORT_SYMBOL(__delay);
static void delay_loop(unsigned long delta)
{
unsigned long end;
end = get_tod_clock_monotonic() + delta;
while (!tod_after(get_tod_clock_monotonic(), end))
cpu_relax();
}
void __udelay(unsigned long usecs)
{
delay_loop(usecs << 12);
}
EXPORT_SYMBOL(__udelay);
void __ndelay(unsigned long nsecs)
{
nsecs <<= 9;
do_div(nsecs, 125);
delay_loop(nsecs);
}
EXPORT_SYMBOL(__ndelay);