atomic.h

来自「Linux Kernel 2.6.9 for OMAP1710」· C头文件 代码 · 共 607 行

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 *
 * But use these as seldom as possible since they are much more slower
 * than regular operations.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1996, 97, 99, 2000, 03, 04 by Ralf Baechle
 */

/*
 * As workaround for the ATOMIC_DEC_AND_LOCK / atomic_dec_and_lock mess in
 * <linux/spinlock.h> we have to include <linux/spinlock.h> outside the
 * main big wrapper ...
 */
#include <linux/config.h>
#include <linux/spinlock.h>

#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H

extern spinlock_t atomic_lock;

typedef struct { volatile int counter; } atomic_t;

#define ATOMIC_INIT(i)    { (i) }

/*
 * atomic_read - read atomic variable
 * @v: pointer of type atomic_t
 *
 * Atomically reads the value of @v.
 */
#define atomic_read(v)		((v)->counter)

/*
 * atomic_set - set atomic variable
 * @v: pointer of type atomic_t
 * @i: required value
 *
 * Atomically sets the value of @v to @i.
 */
#define atomic_set(v,i)		((v)->counter = (i))

#ifdef CONFIG_CPU_HAS_LLSC

/*
 * atomic_add - add integer to atomic variable
 * @i: integer value to add
 * @v: pointer of type atomic_t
 *
 * Atomically adds @i to @v.
 */
static __inline__ void atomic_add(int i, atomic_t * v)
{
	unsigned long temp;

	__asm__ __volatile__(
	"1:	ll	%0, %1		# atomic_add		\n"
	"	addu	%0, %2					\n"
	"	sc	%0, %1					\n"
	"	beqz	%0, 1b					\n"
	: "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter));
}

/*
 * atomic_sub - subtract the atomic variable
 * @i: integer value to subtract
 * @v: pointer of type atomic_t
 *
 * Atomically subtracts @i from @v.
 */
static __inline__ void atomic_sub(int i, atomic_t * v)
{
	unsigned long temp;

	__asm__ __volatile__(
	"1:	ll	%0, %1		# atomic_sub		\n"
	"	subu	%0, %2					\n"
	"	sc	%0, %1					\n"
	"	beqz	%0, 1b					\n"
	: "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter));
}

/*
 * Same as above, but return the result value
 */
static __inline__ int atomic_add_return(int i, atomic_t * v)
{
	unsigned long temp, result;

	__asm__ __volatile__(
	"1:	ll	%1, %2		# atomic_add_return	\n"
	"	addu	%0, %1, %3				\n"
	"	sc	%0, %2					\n"
	"	beqz	%0, 1b					\n"
	"	addu	%0, %1, %3				\n"
	"	sync						\n"
	: "=&r" (result), "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter)
	: "memory");

	return result;
}

static __inline__ int atomic_sub_return(int i, atomic_t * v)
{
	unsigned long temp, result;

	__asm__ __volatile__(
	"1:	ll	%1, %2		# atomic_sub_return	\n"
	"	subu	%0, %1, %3				\n"
	"	sc	%0, %2					\n"
	"	beqz	%0, 1b					\n"
	"	subu	%0, %1, %3				\n"
	"	sync						\n"
	: "=&r" (result), "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter)
	: "memory");

	return result;
}

/*
 * atomic_sub_if_positive - add integer to atomic variable
 * @v: pointer of type atomic_t
 *
 * Atomically test @v and decrement if it is greater than 0.
 * The function returns the old value of @v minus 1.
 */
static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
{
	unsigned long temp, result;

	__asm__ __volatile__(
	"1:	ll	%1, %2		# atomic_sub_if_positive\n"
	"	subu	%0, %1, %3				\n"
	"	bltz	%0, 1f					\n"
	"	sc	%0, %2					\n"
	"	beqz	%0, 1b					\n"
	"	sync						\n"
	"1:							\n"
	: "=&r" (result), "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter)
	: "memory");

	return result;
}

#else

/*
 * The MIPS I implementation is only atomic with respect to
 * interrupts.  R3000 based multiprocessor machines are rare anyway ...
 *
 * atomic_add - add integer to atomic variable
 * @i: integer value to add
 * @v: pointer of type atomic_t
 *
 * Atomically adds @i to @v.
 */
static __inline__ void atomic_add(int i, atomic_t * v)
{
	unsigned long flags;

	spin_lock_irqsave(&atomic_lock, flags);
	v->counter += i;
	spin_unlock_irqrestore(&atomic_lock, flags);
}

/*
 * atomic_sub - subtract the atomic variable
 * @i: integer value to subtract
 * @v: pointer of type atomic_t
 *
 * Atomically subtracts @i from @v.
 */
static __inline__ void atomic_sub(int i, atomic_t * v)
{
	unsigned long flags;

	spin_lock_irqsave(&atomic_lock, flags);
	v->counter -= i;
	spin_unlock_irqrestore(&atomic_lock, flags);
}

static __inline__ int atomic_add_return(int i, atomic_t * v)
{
	unsigned long flags;
	int temp;

	spin_lock_irqsave(&atomic_lock, flags);
	temp = v->counter;
	temp += i;
	v->counter = temp;
	spin_unlock_irqrestore(&atomic_lock, flags);

	return temp;
}

static __inline__ int atomic_sub_return(int i, atomic_t * v)
{
	unsigned long flags;
	int temp;

	spin_lock_irqsave(&atomic_lock, flags);
	temp = v->counter;
	temp -= i;
	v->counter = temp;
	spin_unlock_irqrestore(&atomic_lock, flags);

	return temp;
}

/*
 * atomic_sub_if_positive - add integer to atomic variable
 * @v: pointer of type atomic_t
 *
 * Atomically test @v and decrement if it is greater than 0.
 * The function returns the old value of @v minus 1.
 */
static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
{
	unsigned long flags;
	int temp;

	spin_lock_irqsave(&atomic_lock, flags);
	temp = v->counter;
	temp -= i;
	if (temp >= 0)
		v->counter = temp;
	spin_unlock_irqrestore(&atomic_lock, flags);

	return temp;
}

#endif /* CONFIG_CPU_HAS_LLSC */

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

/*
 * atomic_sub_and_test - subtract value from variable and test result
 * @i: integer value to subtract
 * @v: pointer of type atomic_t
 *
 * Atomically subtracts @i from @v and returns
 * true if the result is zero, or false for all
 * other cases.
 */
#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)

/*
 * atomic_inc_and_test - increment and test
 * @v: pointer of type atomic_t
 *
 * Atomically increments @v by 1
 * and returns true if the result is zero, or false for all
 * other cases.
 */
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)

/*
 * atomic_dec_and_test - decrement by 1 and test
 * @v: pointer of type atomic_t
 *
 * Atomically decrements @v by 1 and
 * returns true if the result is 0, or false for all other
 * cases.
 */
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)

/*
 * atomic_dec_if_positive - decrement by 1 if old value positive
 * @v: pointer of type atomic_t
 */
#define atomic_dec_if_positive(v)	atomic_sub_if_positive(1, v)

/*
 * atomic_inc - increment atomic variable
 * @v: pointer of type atomic_t
 *
 * Atomically increments @v by 1.
 */
#define atomic_inc(v) atomic_add(1,(v))

/*
 * atomic_dec - decrement and test
 * @v: pointer of type atomic_t
 *
 * Atomically decrements @v by 1.
 */
#define atomic_dec(v) atomic_sub(1,(v))

/*
 * atomic_add_negative - add and test if negative
 * @v: pointer of type atomic_t
 * @i: integer value to add
 *
 * Atomically adds @i to @v and returns true
 * if the result is negative, or false when
 * result is greater than or equal to zero.
 */
#define atomic_add_negative(i,v) (atomic_add_return(i, (v)) < 0)

#ifdef CONFIG_MIPS64

typedef struct { volatile __s64 counter; } atomic64_t;

#define ATOMIC64_INIT(i)    { (i) }

/*
 * atomic64_read - read atomic variable
 * @v: pointer of type atomic64_t
 *
 */
#define atomic64_read(v)	((v)->counter)

/*
 * atomic64_set - set atomic variable
 * @v: pointer of type atomic64_t
 * @i: required value
 */
#define atomic64_set(v,i)	((v)->counter = (i))

#ifdef CONFIG_CPU_HAS_LLDSCD

/*
 * atomic64_add - add integer to atomic variable
 * @i: integer value to add
 * @v: pointer of type atomic64_t
 *
 * Atomically adds @i to @v.
 */
static __inline__ void atomic64_add(long i, atomic64_t * v)
{
	unsigned long temp;

	__asm__ __volatile__(
	"1:	lld	%0, %1		# atomic64_add		\n"
	"	addu	%0, %2					\n"
	"	scd	%0, %1					\n"
	"	beqz	%0, 1b					\n"
	: "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter));
}

/*
 * atomic64_sub - subtract the atomic variable
 * @i: integer value to subtract
 * @v: pointer of type atomic64_t
 *
 * Atomically subtracts @i from @v.
 */
static __inline__ void atomic64_sub(long i, atomic64_t * v)
{
	unsigned long temp;

	__asm__ __volatile__(
	"1:	lld	%0, %1		# atomic64_sub		\n"
	"	subu	%0, %2					\n"
	"	scd	%0, %1					\n"
	"	beqz	%0, 1b					\n"
	: "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter));
}

/*
 * Same as above, but return the result value
 */
static __inline__ long atomic64_add_return(long i, atomic64_t * v)
{
	unsigned long temp, result;

	__asm__ __volatile__(
	"1:	lld	%1, %2		# atomic64_add_return	\n"
	"	addu	%0, %1, %3				\n"
	"	scd	%0, %2					\n"
	"	beqz	%0, 1b					\n"
	"	addu	%0, %1, %3				\n"
	"	sync						\n"
	: "=&r" (result), "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter)
	: "memory");

	return result;
}

static __inline__ long atomic64_sub_return(long i, atomic64_t * v)
{
	unsigned long temp, result;

	__asm__ __volatile__(
	"1:	lld	%1, %2		# atomic64_sub_return	\n"
	"	subu	%0, %1, %3				\n"
	"	scd	%0, %2					\n"
	"	beqz	%0, 1b					\n"
	"	subu	%0, %1, %3				\n"
	"	sync						\n"
	: "=&r" (result), "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter)
	: "memory");

	return result;
}

/*
 * atomic64_sub_if_positive - add integer to atomic variable
 * @v: pointer of type atomic64_t
 *
 * Atomically test @v and decrement if it is greater than 0.
 * The function returns the old value of @v minus 1.
 */
static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
{
	unsigned long temp, result;

	__asm__ __volatile__(
	"1:	lld	%1, %2		# atomic64_sub_if_positive\n"
	"	dsubu	%0, %1, %3				\n"
	"	bltz	%0, 1f					\n"
	"	scd	%0, %2					\n"
	"	beqz	%0, 1b					\n"
	"	sync						\n"
	"1:							\n"
	: "=&r" (result), "=&r" (temp), "=m" (v->counter)
	: "Ir" (i), "m" (v->counter)
	: "memory");

	return result;
}

#else

/*
 * This implementation is only atomic with respect to interrupts.  It can't
 * be used on SMP
 *
 * atomic64_add - add integer to atomic variable
 * @i: integer value to add
 * @v: pointer of type atomic64_t
 *
 * Atomically adds @i to @v.
 */
static __inline__ void atomic64_add(long i, atomic64_t * v)
{
	unsigned long flags;

	spin_lock_irqsave(&atomic_lock, flags);
	v->counter += i;
	spin_unlock_irqrestore(&atomic_lock, flags);
}

/*
 * atomic64_sub - subtract the atomic variable
 * @i: integer value to subtract
 * @v: pointer of type atomic64_t
 *
 * Atomically subtracts @i from @v.
 */
static __inline__ void atomic64_sub(long i, atomic64_t * v)
{
	unsigned long flags;

	spin_lock_irqsave(&atomic_lock, flags);
	v->counter -= i;
	spin_unlock_irqrestore(&atomic_lock, flags);
}

static __inline__ long atomic64_add_return(long i, atomic64_t * v)
{
	unsigned long flags;
	long temp;

	spin_lock_irqsave(&atomic_lock, flags);
	temp = v->counter;
	temp += i;
	v->counter = temp;
	spin_unlock_irqrestore(&atomic_lock, flags);

	return temp;
}

static __inline__ long atomic64_sub_return(long i, atomic64_t * v)
{
	unsigned long flags;
	long temp;

	spin_lock_irqsave(&atomic_lock, flags);
	temp = v->counter;
	temp -= i;
	v->counter = temp;
	spin_unlock_irqrestore(&atomic_lock, flags);

	return temp;
}

/*
 * atomic64_sub_if_positive - add integer to atomic variable
 * @v: pointer of type atomic64_t
 *
 * Atomically test @v and decrement if it is greater than 0.
 * The function returns the old value of @v minus 1.
 */
static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
{
	unsigned long flags;
	long temp;

	spin_lock_irqsave(&atomic_lock, flags);
	temp = v->counter;
	temp -= i;
	if (temp >= 0)
		v->counter = temp;
	spin_unlock_irqrestore(&atomic_lock, flags);

	return temp;
}

#endif /* CONFIG_CPU_HAS_LLDSCD */

#define atomic64_dec_return(v) atomic64_sub_return(1,(v))
#define atomic64_inc_return(v) atomic64_add_return(1,(v))

/*
 * atomic64_sub_and_test - subtract value from variable and test result
 * @i: integer value to subtract
 * @v: pointer of type atomic64_t
 *
 * Atomically subtracts @i from @v and returns
 * true if the result is zero, or false for all
 * other cases.
 */
#define atomic64_sub_and_test(i,v) (atomic64_sub_return((i), (v)) == 0)

/*
 * atomic64_inc_and_test - increment and test
 * @v: pointer of type atomic64_t
 *
 * Atomically increments @v by 1
 * and returns true if the result is zero, or false for all
 * other cases.
 */
#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)

/*
 * atomic64_dec_and_test - decrement by 1 and test
 * @v: pointer of type atomic64_t
 *
 * Atomically decrements @v by 1 and
 * returns true if the result is 0, or false for all other
 * cases.
 */
#define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)

/*
 * atomic64_dec_if_positive - decrement by 1 if old value positive
 * @v: pointer of type atomic64_t
 */
#define atomic64_dec_if_positive(v)	atomic64_sub_if_positive(1, v)

/*
 * atomic64_inc - increment atomic variable
 * @v: pointer of type atomic64_t
 *
 * Atomically increments @v by 1.
 */
#define atomic64_inc(v) atomic64_add(1,(v))

/*
 * atomic64_dec - decrement and test
 * @v: pointer of type atomic64_t
 *
 * Atomically decrements @v by 1.
 */
#define atomic64_dec(v) atomic64_sub(1,(v))

/*
 * atomic64_add_negative - add and test if negative
 * @v: pointer of type atomic64_t
 * @i: integer value to add
 *
 * Atomically adds @i to @v and returns true
 * if the result is negative, or false when
 * result is greater than or equal to zero.
 */
#define atomic64_add_negative(i,v) (atomic64_add_return(i, (v)) < 0)

#endif /* CONFIG_MIPS64 */

/*
 * atomic*_return operations are serializing but not the non-*_return
 * versions.
 */
#define smp_mb__before_atomic_dec()	smp_mb()
#define smp_mb__after_atomic_dec()	smp_mb()
#define smp_mb__before_atomic_inc()	smp_mb()
#define smp_mb__after_atomic_inc()	smp_mb()

#endif /* _ASM_ATOMIC_H */