mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-19 10:44:14 +08:00
94c12cc7d1
Major cleanup of all s390 inline assemblies. They now have a common coding style. Quite a few have been shortened, mainly by using register asm variables. Use of the EX_TABLE macro helps as well. The atomic ops, bit ops and locking inlines new use the Q-constraint if a newer gcc is used. That results in slightly better code. Thanks to Christian Borntraeger for proof reading the changes. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
/*
|
|
* arch/s390/kernel/delay.c
|
|
* Precise Delay Loops for S390
|
|
*
|
|
* S390 version
|
|
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
|
|
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
|
|
*
|
|
* Derived from "arch/i386/lib/delay.c"
|
|
* Copyright (C) 1993 Linus Torvalds
|
|
* Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
|
|
*/
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/delay.h>
|
|
|
|
#ifdef CONFIG_SMP
|
|
#include <asm/smp.h>
|
|
#endif
|
|
|
|
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));
|
|
}
|
|
|
|
/*
|
|
* Waits for 'usecs' microseconds using the tod clock, giving up the time slice
|
|
* of the virtual PU inbetween to avoid congestion.
|
|
*/
|
|
void __udelay(unsigned long usecs)
|
|
{
|
|
uint64_t start_cc;
|
|
|
|
if (usecs == 0)
|
|
return;
|
|
start_cc = get_clock();
|
|
do {
|
|
cpu_relax();
|
|
} while (((get_clock() - start_cc)/4096) < usecs);
|
|
}
|