mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-17 01:04:19 +08:00
6a16fc3220
These duplicate includes have been found with scripts/checkincludes.pl but they have been removed manually to avoid removing false positives. Signed-off-by: Pravin Shedge <pravin.shedge4linux@gmail.com> Signed-off-by: Helge Deller <deller@gmx.de>
73 lines
1.8 KiB
C
73 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Precise Delay Loops for parisc
|
|
*
|
|
* based on code by:
|
|
* Copyright (C) 1993 Linus Torvalds
|
|
* Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
|
|
* Copyright (C) 2008 Jiri Hladky <hladky _dot_ jiri _at_ gmail _dot_ com>
|
|
*
|
|
* parisc implementation:
|
|
* Copyright (C) 2013 Helge Deller <deller@gmx.de>
|
|
*/
|
|
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/preempt.h>
|
|
#include <linux/init.h>
|
|
|
|
#include <asm/delay.h>
|
|
#include <asm/special_insns.h> /* for mfctl() */
|
|
#include <asm/processor.h> /* for boot_cpu_data */
|
|
|
|
/* CR16 based delay: */
|
|
static void __cr16_delay(unsigned long __loops)
|
|
{
|
|
/*
|
|
* Note: Due to unsigned math, cr16 rollovers shouldn't be
|
|
* a problem here. However, on 32 bit, we need to make sure
|
|
* we don't pass in too big a value. The current default
|
|
* value of MAX_UDELAY_MS should help prevent this.
|
|
*/
|
|
u32 bclock, now, loops = __loops;
|
|
int cpu;
|
|
|
|
preempt_disable();
|
|
cpu = smp_processor_id();
|
|
bclock = mfctl(16);
|
|
for (;;) {
|
|
now = mfctl(16);
|
|
if ((now - bclock) >= loops)
|
|
break;
|
|
|
|
/* Allow RT tasks to run */
|
|
preempt_enable();
|
|
asm volatile(" nop\n");
|
|
barrier();
|
|
preempt_disable();
|
|
|
|
/*
|
|
* It is possible that we moved to another CPU, and
|
|
* since CR16's are per-cpu we need to calculate
|
|
* that. The delay must guarantee that we wait "at
|
|
* least" the amount of time. Being moved to another
|
|
* CPU could make the wait longer but we just need to
|
|
* make sure we waited long enough. Rebalance the
|
|
* counter for this CPU.
|
|
*/
|
|
if (unlikely(cpu != smp_processor_id())) {
|
|
loops -= (now - bclock);
|
|
cpu = smp_processor_id();
|
|
bclock = mfctl(16);
|
|
}
|
|
}
|
|
preempt_enable();
|
|
}
|
|
|
|
|
|
void __udelay(unsigned long usecs)
|
|
{
|
|
__cr16_delay(usecs * ((unsigned long)boot_cpu_data.cpu_hz / 1000000UL));
|
|
}
|
|
EXPORT_SYMBOL(__udelay);
|