forked from Minki/linux
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
67 lines
1.9 KiB
C
67 lines
1.9 KiB
C
#ifdef __KERNEL__
|
|
#ifndef _PPC_DELAY_H
|
|
#define _PPC_DELAY_H
|
|
|
|
#include <asm/param.h>
|
|
|
|
/*
|
|
* Copyright 1996, Paul Mackerras.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
|
|
extern unsigned long loops_per_jiffy;
|
|
|
|
extern void __delay(unsigned int loops);
|
|
|
|
/*
|
|
* Note that 19 * 226 == 4294 ==~ 2^32 / 10^6, so
|
|
* loops = (4294 * usecs * loops_per_jiffy * HZ) / 2^32.
|
|
*
|
|
* The mulhwu instruction gives us loops = (a * b) / 2^32.
|
|
* We choose a = usecs * 19 * HZ and b = loops_per_jiffy * 226
|
|
* because this lets us support a wide range of HZ and
|
|
* loops_per_jiffy values without either a or b overflowing 2^32.
|
|
* Thus we need usecs * HZ <= (2^32 - 1) / 19 = 226050910 and
|
|
* loops_per_jiffy <= (2^32 - 1) / 226 = 19004280
|
|
* (which corresponds to ~3800 bogomips at HZ = 100).
|
|
* -- paulus
|
|
*/
|
|
#define __MAX_UDELAY (226050910UL/HZ) /* maximum udelay argument */
|
|
#define __MAX_NDELAY (4294967295UL/HZ) /* maximum ndelay argument */
|
|
|
|
extern __inline__ void __udelay(unsigned int x)
|
|
{
|
|
unsigned int loops;
|
|
|
|
__asm__("mulhwu %0,%1,%2" : "=r" (loops) :
|
|
"r" (x), "r" (loops_per_jiffy * 226));
|
|
__delay(loops);
|
|
}
|
|
|
|
extern __inline__ void __ndelay(unsigned int x)
|
|
{
|
|
unsigned int loops;
|
|
|
|
__asm__("mulhwu %0,%1,%2" : "=r" (loops) :
|
|
"r" (x), "r" (loops_per_jiffy * 5));
|
|
__delay(loops);
|
|
}
|
|
|
|
extern void __bad_udelay(void); /* deliberately undefined */
|
|
extern void __bad_ndelay(void); /* deliberately undefined */
|
|
|
|
#define udelay(n) (__builtin_constant_p(n)? \
|
|
((n) > __MAX_UDELAY? __bad_udelay(): __udelay((n) * (19 * HZ))) : \
|
|
__udelay((n) * (19 * HZ)))
|
|
|
|
#define ndelay(n) (__builtin_constant_p(n)? \
|
|
((n) > __MAX_NDELAY? __bad_ndelay(): __ndelay((n) * HZ)) : \
|
|
__ndelay((n) * HZ))
|
|
|
|
#endif /* defined(_PPC_DELAY_H) */
|
|
#endif /* __KERNEL__ */
|