include/asm-xtensa/atomic.h - maze/linux - Git at Google

 /*
  * include/asm-xtensa/atomic.h
  *
  * Atomic operations that C can't guarantee us.  Useful for resource counting..
  *
  * 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) 2001 - 2005 Tensilica Inc.
  */

 #ifndef _XTENSA_ATOMIC_H
 #define _XTENSA_ATOMIC_H

 #include <linux/stringify.h>

 typedef struct { volatile int counter; } atomic_t;

 #ifdef __KERNEL__
 #include <asm/processor.h>
 #include <asm/system.h>

 #define ATOMIC_INIT(i)	{ (i) }

 /*
  * This Xtensa implementation assumes that the right mechanism
  * for exclusion is for locking interrupts to level 1.
  *
  * Locking interrupts looks like this:
  *
  *    rsil a15, 1
  *    <code>
  *    wsr  a15, PS
  *    rsync
  *
  * Note that a15 is used here because the register allocation
  * done by the compiler is not guaranteed and a window overflow
  * may not occur between the rsil and wsr instructions. By using
  * a15 in the rsil, the machine is guaranteed to be in a state
  * where no register reference will cause an overflow.
  */

 /**
  * 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))

 /**
  * 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 int vval;

     __asm__ __volatile__(
 	"rsil    a15, "__stringify(LOCKLEVEL)"\n\t"
 	"l32i    %0, %2, 0              \n\t"
 	"add     %0, %0, %1             \n\t"
 	"s32i    %0, %2, 0              \n\t"
 	"wsr     a15, "__stringify(PS)"       \n\t"
 	"rsync                          \n"
 	: "=&a" (vval)
 	: "a" (i), "a" (v)
 	: "a15", "memory"
 	);
 }

 /**
  * 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 int vval;

     __asm__ __volatile__(
 	"rsil    a15, "__stringify(LOCKLEVEL)"\n\t"
 	"l32i    %0, %2, 0              \n\t"
 	"sub     %0, %0, %1             \n\t"
 	"s32i    %0, %2, 0              \n\t"
 	"wsr     a15, "__stringify(PS)"       \n\t"
 	"rsync                          \n"
 	: "=&a" (vval)
 	: "a" (i), "a" (v)
 	: "a15", "memory"
 	);
 }

 /*
  * We use atomic_{add|sub}_return to define other functions.
  */

 static inline int atomic_add_return(int i, atomic_t * v)
 {
      unsigned int vval;

     __asm__ __volatile__(
 	"rsil    a15,"__stringify(LOCKLEVEL)"\n\t"
 	"l32i    %0, %2, 0             \n\t"
 	"add     %0, %0, %1            \n\t"
 	"s32i    %0, %2, 0             \n\t"
 	"wsr     a15, "__stringify(PS)"      \n\t"
 	"rsync                         \n"
 	: "=&a" (vval)
 	: "a" (i), "a" (v)
 	: "a15", "memory"
 	);

     return vval;
 }

 static inline int atomic_sub_return(int i, atomic_t * v)
 {
     unsigned int vval;

     __asm__ __volatile__(
 	"rsil    a15,"__stringify(LOCKLEVEL)"\n\t"
 	"l32i    %0, %2, 0             \n\t"
 	"sub     %0, %0, %1            \n\t"
 	"s32i    %0, %2, 0             \n\t"
 	"wsr     a15, "__stringify(PS)"       \n\t"
 	"rsync                         \n"
 	: "=&a" (vval)
 	: "a" (i), "a" (v)
 	: "a15", "memory"
 	);

     return vval;
 }

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

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

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

 /**
  * atomic_dec_return - decrement atomic variable
  * @v: pointer of type atomic_t
  *
  * Atomically decrements @v by 1.
  */
 #define atomic_dec_return(v) atomic_sub_return(1,(v))

 /**
  * atomic_dec_and_test - decrement 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_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_add_return(1,(v)) == 0)

 /**
  * 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)

 #define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))

 /**
  * atomic_add_unless - add unless the number is a given value
  * @v: pointer of type atomic_t
  * @a: the amount to add to v...
  * @u: ...unless v is equal to u.
  *
  * Atomically adds @a to @v, so long as it was not @u.
  * Returns non-zero if @v was not @u, and zero otherwise.
  */
 #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 != (u);						\
 })
 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

 static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
 {
     unsigned int all_f = -1;
     unsigned int vval;

     __asm__ __volatile__(
 	"rsil    a15,"__stringify(LOCKLEVEL)"\n\t"
 	"l32i    %0, %2, 0             \n\t"
 	"xor     %1, %4, %3            \n\t"
 	"and     %0, %0, %4            \n\t"
 	"s32i    %0, %2, 0             \n\t"
 	"wsr     a15, "__stringify(PS)"      \n\t"
 	"rsync                         \n"
 	: "=&a" (vval), "=a" (mask)
 	: "a" (v), "a" (all_f), "1" (mask)
 	: "a15", "memory"
 	);
 }

 static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
 {
     unsigned int vval;

     __asm__ __volatile__(
 	"rsil    a15,"__stringify(LOCKLEVEL)"\n\t"
 	"l32i    %0, %2, 0             \n\t"
 	"or      %0, %0, %1            \n\t"
 	"s32i    %0, %2, 0             \n\t"
 	"wsr     a15, "__stringify(PS)"       \n\t"
 	"rsync                         \n"
 	: "=&a" (vval)
 	: "a" (mask), "a" (v)
 	: "a15", "memory"
 	);
 }

 /* 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()

 #include <asm-generic/atomic.h>
 #endif /* __KERNEL__ */

 #endif /* _XTENSA_ATOMIC_H */
	/*
	* include/asm-xtensa/atomic.h
	*
	* Atomic operations that C can't guarantee us. Useful for resource counting..
	*
	* 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) 2001 - 2005 Tensilica Inc.
	*/

	#ifndef _XTENSA_ATOMIC_H
	#define _XTENSA_ATOMIC_H

	#include <linux/stringify.h>

	typedef struct { volatile int counter; } atomic_t;

	#ifdef __KERNEL__
	#include <asm/processor.h>
	#include <asm/system.h>

	#define ATOMIC_INIT(i) { (i) }

	/*
	* This Xtensa implementation assumes that the right mechanism
	* for exclusion is for locking interrupts to level 1.
	*
	* Locking interrupts looks like this:
	*
	* rsil a15, 1
	* <code>
	* wsr a15, PS
	* rsync
	*
	* Note that a15 is used here because the register allocation
	* done by the compiler is not guaranteed and a window overflow
	* may not occur between the rsil and wsr instructions. By using
	* a15 in the rsil, the machine is guaranteed to be in a state
	* where no register reference will cause an overflow.
	*/

	/**
	* 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))

	/**
	* 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 int vval;

	__asm__ __volatile__(
	"rsil a15, "__stringify(LOCKLEVEL)"\n\t"
	"l32i %0, %2, 0 \n\t"
	"add %0, %0, %1 \n\t"
	"s32i %0, %2, 0 \n\t"
	"wsr a15, "__stringify(PS)" \n\t"
	"rsync \n"
	: "=&a" (vval)
	: "a" (i), "a" (v)
	: "a15", "memory"
	);
	}

	/**
	* 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 int vval;

	__asm__ __volatile__(
	"rsil a15, "__stringify(LOCKLEVEL)"\n\t"
	"l32i %0, %2, 0 \n\t"
	"sub %0, %0, %1 \n\t"
	"s32i %0, %2, 0 \n\t"
	"wsr a15, "__stringify(PS)" \n\t"
	"rsync \n"
	: "=&a" (vval)
	: "a" (i), "a" (v)
	: "a15", "memory"
	);
	}

	/*
	* We use atomic_{add\|sub}_return to define other functions.
	*/

	static inline int atomic_add_return(int i, atomic_t * v)
	{
	unsigned int vval;

	__asm__ __volatile__(
	"rsil a15,"__stringify(LOCKLEVEL)"\n\t"
	"l32i %0, %2, 0 \n\t"
	"add %0, %0, %1 \n\t"
	"s32i %0, %2, 0 \n\t"
	"wsr a15, "__stringify(PS)" \n\t"
	"rsync \n"
	: "=&a" (vval)
	: "a" (i), "a" (v)
	: "a15", "memory"
	);

	return vval;
	}

	static inline int atomic_sub_return(int i, atomic_t * v)
	{
	unsigned int vval;

	__asm__ __volatile__(
	"rsil a15,"__stringify(LOCKLEVEL)"\n\t"
	"l32i %0, %2, 0 \n\t"
	"sub %0, %0, %1 \n\t"
	"s32i %0, %2, 0 \n\t"
	"wsr a15, "__stringify(PS)" \n\t"
	"rsync \n"
	: "=&a" (vval)
	: "a" (i), "a" (v)
	: "a15", "memory"
	);

	return vval;
	}

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

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

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

	/**
	* atomic_dec_return - decrement atomic variable
	* @v: pointer of type atomic_t
	*
	* Atomically decrements @v by 1.
	*/
	#define atomic_dec_return(v) atomic_sub_return(1,(v))

	/**
	* atomic_dec_and_test - decrement 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_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_add_return(1,(v)) == 0)

	/**
	* 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)

	#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
	#define atomic_xchg(v, new) (xchg(&((v)->counter), new))

	/**
	* atomic_add_unless - add unless the number is a given value
	* @v: pointer of type atomic_t
	* @a: the amount to add to v...
	* @u: ...unless v is equal to u.
	*
	* Atomically adds @a to @v, so long as it was not @u.
	* Returns non-zero if @v was not @u, and zero otherwise.
	*/
	#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 != (u); \
	})
	#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

	static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
	{
	unsigned int all_f = -1;
	unsigned int vval;

	__asm__ __volatile__(
	"rsil a15,"__stringify(LOCKLEVEL)"\n\t"
	"l32i %0, %2, 0 \n\t"
	"xor %1, %4, %3 \n\t"
	"and %0, %0, %4 \n\t"
	"s32i %0, %2, 0 \n\t"
	"wsr a15, "__stringify(PS)" \n\t"
	"rsync \n"
	: "=&a" (vval), "=a" (mask)
	: "a" (v), "a" (all_f), "1" (mask)
	: "a15", "memory"
	);
	}

	static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
	{
	unsigned int vval;

	__asm__ __volatile__(
	"rsil a15,"__stringify(LOCKLEVEL)"\n\t"
	"l32i %0, %2, 0 \n\t"
	"or %0, %0, %1 \n\t"
	"s32i %0, %2, 0 \n\t"
	"wsr a15, "__stringify(PS)" \n\t"
	"rsync \n"
	: "=&a" (vval)
	: "a" (mask), "a" (v)
	: "a15", "memory"
	);
	}

	/* 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()

	#include <asm-generic/atomic.h>
	#endif /* __KERNEL__ */

	#endif /* _XTENSA_ATOMIC_H */