/* * 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, 1997, 2000 by Ralf Baechle */#ifndef __ASM_ATOMIC_H#define __ASM_ATOMIC_H#include <linux/config.h>typedef struct { volatile int counter; } atomic_t;#ifdef __KERNEL__#define ATOMIC_INIT(i)    { (i) }/* * 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)	((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))#ifndef CONFIG_CPU_HAS_LLSC#include <asm/system.h>/* * 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.  Note that the guaranteed useful range * of an atomic_t is only 24 bits. */extern __inline__ void atomic_add(int i, atomic_t * v){	int	flags;	save_flags(flags);	cli();	v->counter += i;	restore_flags(flags);}/* * atomic_sub - subtract the atomic variable * @i: integer value to subtract * @v: pointer of type atomic_t * * Atomically subtracts @i from @v.  Note that the guaranteed * useful range of an atomic_t is only 24 bits. */extern __inline__ void atomic_sub(int i, atomic_t * v){	int	flags;	save_flags(flags);	cli();	v->counter -= i;	restore_flags(flags);}extern __inline__ int atomic_add_return(int i, atomic_t * v){	int	temp, flags;	save_flags(flags);	cli();	temp = v->counter;	temp += i;	v->counter = temp;	restore_flags(flags);	return temp;}extern __inline__ int atomic_sub_return(int i, atomic_t * v){	int	temp, flags;	save_flags(flags);	cli();	temp = v->counter;	temp -= i;	v->counter = temp;	restore_flags(flags);	return temp;}#else/* * ... while for MIPS II and better we can use ll/sc instruction.  This * implementation is SMP safe ... *//* * atomic_add - add integer to atomic variable * @i: integer value to add * @v: pointer of type atomic_t * * Atomically adds @i to @v.  Note that the guaranteed useful range * of an atomic_t is only 24 bits. */extern __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.  Note that the guaranteed * useful range of an atomic_t is only 24 bits. */extern __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 */extern __inline__ int atomic_add_return(int i, atomic_t * v){	unsigned long temp, result;	__asm__ __volatile__(		".set push               # atomic_add_return\n"		".set noreorder                             \n"		"1:   ll      %1, %2                        \n"		"     addu    %0, %1, %3                    \n"		"     sc      %0, %2                        \n"		"     beqz    %0, 1b                        \n"		"     addu    %0, %1, %3                    \n"		".set pop                                   \n"		: "=&r" (result), "=&r" (temp), "=m" (v->counter)		: "Ir" (i), "m" (v->counter)		: "memory");	return result;}extern __inline__ int atomic_sub_return(int i, atomic_t * v){	unsigned long temp, result;	__asm__ __volatile__(		".set push                                   \n"		".set noreorder           # atomic_sub_return\n"		"1:   ll    %1, %2                           \n"		"     subu  %0, %1, %3                       \n"		"     sc    %0, %2                           \n"		"     beqz  %0, 1b                           \n"		"     subu  %0, %1, %3                       \n"		".set pop                                    \n"		: "=&r" (result), "=&r" (temp), "=m" (v->counter)		: "Ir" (i), "m" (v->counter)		: "memory");	return result;}#endif#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.  Note that the guaranteed * useful range of an atomic_t is only 24 bits. */#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.  Note that the guaranteed * useful range of an atomic_t is only 24 bits. */#define atomic_inc_and_test(v) (atomic_inc_return(1, (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.  Note that the guaranteed * useful range of an atomic_t is only 24 bits. */#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)/* * atomic_inc - increment atomic variable * @v: pointer of type atomic_t * * Atomically increments @v by 1.  Note that the guaranteed * useful range of an atomic_t is only 24 bits. */#define atomic_inc(v) atomic_add(1,(v))/* * atomic_dec - decrement and test * @v: pointer of type atomic_t * * Atomically decrements @v by 1.  Note that the guaranteed * useful range of an atomic_t is only 24 bits. */#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.  Note that the guaranteed * useful range of an atomic_t is only 24 bits. * * Currently not implemented for MIPS. *//* Atomic operations are already serializing */#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 /* defined(__KERNEL__) */#endif /* __ASM_ATOMIC_H */