49 строки
1.1 KiB
C
49 строки
1.1 KiB
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)
|
|
{
|
|
/*
|
|
* To end the bloody studid and useless discussion about the
|
|
* BogoMips number I took the liberty to define the __delay
|
|
* function in a way that that resulting BogoMips number will
|
|
* yield the megahertz number of the cpu. The important function
|
|
* is udelay and that is done using the tod clock. -- martin.
|
|
*/
|
|
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);
|