/* 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 */