/* MN10300 Atomic xchg/cmpxchg operations
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifndef _ASM_CMPXCHG_H
#define _ASM_CMPXCHG_H

#include <asm/irqflags.h>

#ifdef CONFIG_SMP
#ifdef CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT
static inline
unsigned long __xchg(volatile unsigned long *m, unsigned long val)
{
unsigned long status;
unsigned long oldval;

asm volatile(
"1: mov %4,(_AAR,%3) \n"
" mov (_ADR,%3),%1 \n"
" mov %5,(_ADR,%3) \n"
" mov (_ADR,%3),%0 \n" /* flush */
" mov (_ASR,%3),%0 \n"
" or %0,%0 \n"
" bne 1b \n"
: "=&r"(status), "=&r"(oldval), "=m"(*m)
: "a"(ATOMIC_OPS_BASE_ADDR), "r"(m), "r"(val)
: "memory", "cc");

return oldval;
}

static inline unsigned long __cmpxchg(volatile unsigned long *m,
unsigned long old, unsigned long new)
{
unsigned long status;
unsigned long oldval;

asm volatile(
"1: mov %4,(_AAR,%3) \n"
" mov (_ADR,%3),%1 \n"
" cmp %5,%1 \n"
" bne 2f \n"
" mov %6,(_ADR,%3) \n"
"2: mov (_ADR,%3),%0 \n" /* flush */
" mov (_ASR,%3),%0 \n"
" or %0,%0 \n"
" bne 1b \n"
: "=&r"(status), "=&r"(oldval), "=m"(*m)
: "a"(ATOMIC_OPS_BASE_ADDR), "r"(m),
"r"(old), "r"(new)
: "memory", "cc");

return oldval;
}
#else /* CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT */
#error "No SMP atomic operation support!"
#endif /* CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT */

#else /* CONFIG_SMP */

/*
* Emulate xchg for non-SMP MN10300
*/
struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((struct __xchg_dummy *)(x))

static inline
unsigned long __xchg(volatile unsigned long *m, unsigned long val)
{
unsigned long oldval;
unsigned long flags;

flags = arch_local_cli_save();
oldval = *m;
*m = val;
arch_local_irq_restore(flags);
return oldval;
}

/*
* Emulate cmpxchg for non-SMP MN10300
*/
static inline unsigned long __cmpxchg(volatile unsigned long *m,
unsigned long old, unsigned long new)
{
unsigned long oldval;
unsigned long flags;

flags = arch_local_cli_save();
oldval = *m;
if (oldval == old)
*m = new;
arch_local_irq_restore(flags);
return oldval;
}

#endif /* CONFIG_SMP */

#define xchg(ptr, v) \
((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr), \
(unsigned long)(v)))

#define cmpxchg(ptr, o, n) \
((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr), \
(unsigned long)(o), \
(unsigned long)(n)))

#endif /* _ASM_CMPXCHG_H */