[linux-block.git] / arch / s390 / lib / delay.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);
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Precise Delay Loops for S390
	4	*
	5	* Copyright IBM Corp. 1999, 2008
	6	* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
	7	*/
	8
	9	#include <linux/processor.h>
	10	#include <linux/delay.h>
	11	#include <asm/div64.h>
	12	#include <asm/timex.h>
	13
	14	void __delay(unsigned long loops)
	15	{
	16	/*
	17	* Loop 'loops' times. Callers must not assume a specific
	18	* amount of time passes before this function returns.
	19	*/
	20	asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
	21	}
	22	EXPORT_SYMBOL(__delay);
	23
	24	static void delay_loop(unsigned long delta)
	25	{
	26	unsigned long end;
	27
	28	end = get_tod_clock_monotonic() + delta;
	29	while (!tod_after(get_tod_clock_monotonic(), end))
	30	cpu_relax();
	31	}
	32
	33	void __udelay(unsigned long usecs)
	34	{
	35	delay_loop(usecs << 12);
	36	}
	37	EXPORT_SYMBOL(__udelay);
	38
	39	void __ndelay(unsigned long nsecs)
	40	{
	41	nsecs <<= 9;
	42	do_div(nsecs, 125);
	43	delay_loop(nsecs);
	44	}
	45	EXPORT_SYMBOL(__ndelay);