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// SPDX-License-Identifier: GPL-2.0
/*
* Precise Delay Loops for Meta
*
* Copyright (C) 1993 Linus Torvalds
* Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
* Copyright (C) 2007,2009 Imagination Technologies Ltd.
*
*/
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <asm/core_reg.h>
#include <asm/processor.h>
/*
* TXTACTCYC is only 24 bits, so on chips with fast clocks it will wrap
* many times per-second. If it does wrap __delay will return prematurely,
* but this is only likely with large delay values.
*
* We also can't implement read_current_timer() with TXTACTCYC due to
* this wrapping behaviour.
*/
#define rdtimer(t) t = __core_reg_get(TXTACTCYC)
void __delay(unsigned long loops)
{
unsigned long bclock, now;
rdtimer(bclock);
do {
asm("NOP");
rdtimer(now);
} while ((now-bclock) < loops);
}
EXPORT_SYMBOL(__delay);
inline void __const_udelay(unsigned long xloops)
{
u64 loops = (u64)xloops * (u64)loops_per_jiffy * HZ;
__delay(loops >> 32);
}
EXPORT_SYMBOL(__const_udelay);
void __udelay(unsigned long usecs)
{
__const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
}
EXPORT_SYMBOL(__udelay);
void __ndelay(unsigned long nsecs)
{
__const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
}
EXPORT_SYMBOL(__ndelay);
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