atomic.h

/* MN10300 Atomic counter operations
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * 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_ATOMIC_H
#define _ASM_ATOMIC_H

#include <asm/irqflags.h>

#ifndef __ASSEMBLY__

#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)))

#define atomic_xchg(ptr, v)		(xchg(&(ptr)->counter, (v)))
#define atomic_cmpxchg(v, old, new)	(cmpxchg(&((v)->counter), (old), (new)))

#endif /* !__ASSEMBLY__ */

#ifndef CONFIG_SMP
#include <asm-generic/atomic.h>
#else

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 */

#define ATOMIC_INIT(i)	{ (i) }

#ifdef __KERNEL__

/**
 * atomic_read - read atomic variable
 * @v: pointer of type atomic_t
 *
 * Atomically reads the value of @v.  Note that the guaranteed
 * useful range of an atomic_t is only 24 bits.
 */
#define atomic_read(v)	(ACCESS_ONCE((v)->counter))

/**
 * atomic_set - set atomic variable
 * @v: pointer of type atomic_t
 * @i: required value
 *
 * Atomically sets the value of @v to @i.  Note that the guaranteed
 * useful range of an atomic_t is only 24 bits.
 */
#define atomic_set(v, i) (((v)->counter) = (i))

/**
 * atomic_add_return - add integer to atomic variable
 * @i: integer value to add
 * @v: pointer of type atomic_t
 *
 * Atomically adds @i to @v and returns the result
 * Note that the guaranteed useful range of an atomic_t is only 24 bits.
 */
static inline int atomic_add_return(int i, atomic_t *v)
{
	int retval;
#ifdef CONFIG_SMP
	int status;

	asm volatile(
		"1:	mov	%4,(_AAR,%3)	\n"
		"	mov	(_ADR,%3),%1	\n"
		"	add	%5,%1		\n"
		"	mov	%1,(_ADR,%3)	\n"
		"	mov	(_ADR,%3),%0	\n"	/* flush */
		"	mov	(_ASR,%3),%0	\n"
		"	or	%0,%0		\n"
		"	bne	1b		\n"
		: "=&r"(status), "=&r"(retval), "=m"(v->counter)
		: "a"(ATOMIC_OPS_BASE_ADDR), "r"(&v->counter), "r"(i)
		: "memory", "cc");

#else
	unsigned long flags;

	flags = arch_local_cli_save();
	retval = v->counter;
	retval += i;
	v->counter = retval;
	arch_local_irq_restore(flags);
#endif
	return retval;
}

/**
 * atomic_sub_return - subtract integer from atomic variable
 * @i: integer value to subtract
 * @v: pointer of type atomic_t
 *
 * Atomically subtracts @i from @v and returns the result
 * Note that the guaranteed useful range of an atomic_t is only 24 bits.
 */
static inline int atomic_sub_return(int i, atomic_t *v)
{
	int retval;
#ifdef CONFIG_SMP
	int status;

	asm volatile(
		"1:	mov	%4,(_AAR,%3)	\n"
		"	mov	(_ADR,%3),%1	\n"
		"	sub	%5,%1		\n"
		"	mov	%1,(_ADR,%3)	\n"
		"	mov	(_ADR,%3),%0	\n"	/* flush */
		"	mov	(_ASR,%3),%0	\n"
		"	or	%0,%0		\n"
		"	bne	1b		\n"
		: "=&r"(status), "=&r"(retval), "=m"(v->counter)
		: "a"(ATOMIC_OPS_BASE_ADDR), "r"(&v->counter), "r"(i)
		: "memory", "cc");

#else
	unsigned long flags;
	flags = arch_local_cli_save();
	retval = v->counter;
	retval -= i;
	v->counter = retval;
	arch_local_irq_restore(flags);
#endif
	return retval;
}

static inline int atomic_add_negative(int i, atomic_t *v)
{
	return atomic_add_return(i, v) < 0;
}

static inline void atomic_add(int i, atomic_t *v)
{
	atomic_add_return(i, v);
}

static inline void atomic_sub(int i, atomic_t *v)
{
	atomic_sub_return(i, v);
}

static inline void atomic_inc(atomic_t *v)
{
	atomic_add_return(1, v);
}

static inline void atomic_dec(atomic_t *v)
{
	atomic_sub_return(1, v);
}

#define atomic_dec_return(v)		atomic_sub_return(1, (v))
#define atomic_inc_return(v)		atomic_add_return(1, (v))

#define atomic_sub_and_test(i, v)	(atomic_sub_return((i), (v)) == 0)
#define atomic_dec_and_test(v)		(atomic_sub_return(1, (v)) == 0)
#define atomic_inc_and_test(v)		(atomic_add_return(1, (v)) == 0)

#define __atomic_add_unless(v, a, u)				\
({								\
	int c, old;						\
	c = atomic_read(v);					\
	while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
		c = old;					\
	c;							\
})


/**
 * atomic_clear_mask - Atomically clear bits in memory
 * @mask: Mask of the bits to be cleared
 * @v: pointer to word in memory
 *
 * Atomically clears the bits set in mask from the memory word specified.
 */
static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
{
#ifdef CONFIG_SMP
	int status;

	asm volatile(
		"1:	mov	%3,(_AAR,%2)	\n"
		"	mov	(_ADR,%2),%0	\n"
		"	and	%4,%0		\n"
		"	mov	%0,(_ADR,%2)	\n"
		"	mov	(_ADR,%2),%0	\n"	/* flush */
		"	mov	(_ASR,%2),%0	\n"
		"	or	%0,%0		\n"
		"	bne	1b		\n"
		: "=&r"(status), "=m"(*addr)
		: "a"(ATOMIC_OPS_BASE_ADDR), "r"(addr), "r"(~mask)
		: "memory", "cc");
#else
	unsigned long flags;

	mask = ~mask;
	flags = arch_local_cli_save();
	*addr &= mask;
	arch_local_irq_restore(flags);
#endif
}

/**
 * atomic_set_mask - Atomically set bits in memory
 * @mask: Mask of the bits to be set
 * @v: pointer to word in memory
 *
 * Atomically sets the bits set in mask from the memory word specified.
 */
static inline void atomic_set_mask(unsigned long mask, unsigned long *addr)
{
#ifdef CONFIG_SMP
	int status;

	asm volatile(
		"1:	mov	%3,(_AAR,%2)	\n"
		"	mov	(_ADR,%2),%0	\n"
		"	or	%4,%0		\n"
		"	mov	%0,(_ADR,%2)	\n"
		"	mov	(_ADR,%2),%0	\n"	/* flush */
		"	mov	(_ASR,%2),%0	\n"
		"	or	%0,%0		\n"
		"	bne	1b		\n"
		: "=&r"(status), "=m"(*addr)
		: "a"(ATOMIC_OPS_BASE_ADDR), "r"(addr), "r"(mask)
		: "memory", "cc");
#else
	unsigned long flags;

	flags = arch_local_cli_save();
	*addr |= mask;
	arch_local_irq_restore(flags);
#endif
}

/* Atomic operations are already serializing on MN10300??? */
#define smp_mb__before_atomic_dec()	barrier()
#define smp_mb__after_atomic_dec()	barrier()
#define smp_mb__before_atomic_inc()	barrier()
#define smp_mb__after_atomic_inc()	barrier()

#endif /* __KERNEL__ */
#endif /* CONFIG_SMP */
#endif /* _ASM_ATOMIC_H */