86 lines
2.1 KiB
C
86 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Copyright (C) 2008 Michal Simek
|
|
* Copyright (C) 2007 John Williams
|
|
* Copyright (C) 2006 Atmark Techno, Inc.
|
|
*/
|
|
|
|
#ifndef _ASM_MICROBLAZE_DELAY_H
|
|
#define _ASM_MICROBLAZE_DELAY_H
|
|
|
|
#include <linux/param.h>
|
|
|
|
static inline void __delay(unsigned long loops)
|
|
{
|
|
asm volatile ("# __delay \n\t" \
|
|
"1: addi %0, %0, -1\t\n" \
|
|
"bneid %0, 1b \t\n" \
|
|
"nop \t\n"
|
|
: "=r" (loops)
|
|
: "0" (loops));
|
|
}
|
|
|
|
/*
|
|
* Note that 19 * 226 == 4294 ==~ 2^32 / 10^6, so
|
|
* loops = (4294 * usecs * loops_per_jiffy * HZ) / 2^32.
|
|
*
|
|
* The mul 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 unsigned long loops_per_jiffy;
|
|
|
|
static inline void __udelay(unsigned int x)
|
|
{
|
|
|
|
unsigned long long tmp =
|
|
(unsigned long long)x * (unsigned long long)loops_per_jiffy \
|
|
* 226LL;
|
|
unsigned loops = tmp >> 32;
|
|
|
|
/*
|
|
__asm__("mulxuu %0,%1,%2" : "=r" (loops) :
|
|
"r" (x), "r" (loops_per_jiffy * 226));
|
|
*/
|
|
__delay(loops);
|
|
}
|
|
|
|
extern void __bad_udelay(void); /* deliberately undefined */
|
|
extern void __bad_ndelay(void); /* deliberately undefined */
|
|
|
|
#define udelay(n) \
|
|
({ \
|
|
if (__builtin_constant_p(n)) { \
|
|
if ((n) / __MAX_UDELAY >= 1) \
|
|
__bad_udelay(); \
|
|
else \
|
|
__udelay((n) * (19 * HZ)); \
|
|
} else { \
|
|
__udelay((n) * (19 * HZ)); \
|
|
} \
|
|
})
|
|
|
|
#define ndelay(n) \
|
|
({ \
|
|
if (__builtin_constant_p(n)) { \
|
|
if ((n) / __MAX_NDELAY >= 1) \
|
|
__bad_ndelay(); \
|
|
else \
|
|
__udelay((n) * HZ); \
|
|
} else { \
|
|
__udelay((n) * HZ); \
|
|
} \
|
|
})
|
|
|
|
#define muldiv(a, b, c) (((a)*(b))/(c))
|
|
|
|
#endif /* _ASM_MICROBLAZE_DELAY_H */
|