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// SPDX-License-Identifier: GPL-2.0-only
/*
* Delay loops based on the OpenRISC implementation.
*
* Copyright (C) 2012 ARM Limited
*
* Author: Will Deacon <will.deacon@arm.com>
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/timex.h>
#include <clocksource/arm_arch_timer.h>
#define USECS_TO_CYCLES(time_usecs) \
xloops_to_cycles((time_usecs) * 0x10C7UL)
static inline unsigned long xloops_to_cycles(unsigned long xloops)
{
return (xloops * loops_per_jiffy * HZ) >> 32;
}
void __delay(unsigned long cycles)
{
cycles_t start = get_cycles();
if (alternative_has_cap_unlikely(ARM64_HAS_WFXT)) {
u64 end = start + cycles;
/*
* Start with WFIT. If an interrupt makes us resume
* early, use a WFET loop to complete the delay.
*/
wfit(end);
while ((get_cycles() - start) < cycles)
wfet(end);
} else if (arch_timer_evtstrm_available()) {
const cycles_t timer_evt_period =
USECS_TO_CYCLES(ARCH_TIMER_EVT_STREAM_PERIOD_US);
while ((get_cycles() - start + timer_evt_period) < cycles)
wfe();
}
while ((get_cycles() - start) < cycles)
cpu_relax();
}
EXPORT_SYMBOL(__delay);
inline void __const_udelay(unsigned long xloops)
{
__delay(xloops_to_cycles(xloops));
}
EXPORT_SYMBOL(__const_udelay);
void __udelay(unsigned long usecs)
{
__const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */
}
EXPORT_SYMBOL(__udelay);
void __ndelay(unsigned long nsecs)
{
__const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */
}
EXPORT_SYMBOL(__ndelay);
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