arch/xtensa/include/asm/atomic.h - arm/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 - 2008 Tensilica Inc.
  */

 #ifndef _XTENSA_ATOMIC_H
 #define _XTENSA_ATOMIC_H

 #include <linux/stringify.h>
 #include <linux/types.h>

 #ifdef __KERNEL__
 #include <asm/processor.h>
 #include <asm/cmpxchg.h>
 #include <asm/barrier.h>

 #define ATOMIC_INIT(i)	{ (i) }

 /*
  * This Xtensa implementation assumes that the right mechanism
  * for exclusion is for locking interrupts to level EXCM_LEVEL.
  *
  * Locking interrupts looks like this:
  *
  *    rsil a15, TOPLEVEL
  *    <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)		READ_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.
  */
 #define atomic_set(v,i)		WRITE_ONCE((v)->counter, (i))

 #if XCHAL_HAVE_S32C1I
 #define ATOMIC_OP(op)							\
 static inline void atomic_##op(int i, atomic_t * v)			\
 {									\
 	unsigned long tmp;						\
 	int result;							\
 									\
 	__asm__ __volatile__(						\
 			"1:     l32i    %1, %3, 0\n"			\
 			"       wsr     %1, scompare1\n"		\
 			"       " #op " %0, %1, %2\n"			\
 			"       s32c1i  %0, %3, 0\n"			\
 			"       bne     %0, %1, 1b\n"			\
 			: "=&a" (result), "=&a" (tmp)			\
 			: "a" (i), "a" (v)				\
 			: "memory"					\
 			);						\
 }									\

 #define ATOMIC_OP_RETURN(op)						\
 static inline int atomic_##op##_return(int i, atomic_t * v)		\
 {									\
 	unsigned long tmp;						\
 	int result;							\
 									\
 	__asm__ __volatile__(						\
 			"1:     l32i    %1, %3, 0\n"			\
 			"       wsr     %1, scompare1\n"		\
 			"       " #op " %0, %1, %2\n"			\
 			"       s32c1i  %0, %3, 0\n"			\
 			"       bne     %0, %1, 1b\n"			\
 			"       " #op " %0, %0, %2\n"			\
 			: "=&a" (result), "=&a" (tmp)			\
 			: "a" (i), "a" (v)				\
 			: "memory"					\
 			);						\
 									\
 	return result;							\
 }

 #define ATOMIC_FETCH_OP(op)						\
 static inline int atomic_fetch_##op(int i, atomic_t * v)		\
 {									\
 	unsigned long tmp;						\
 	int result;							\
 									\
 	__asm__ __volatile__(						\
 			"1:     l32i    %1, %3, 0\n"			\
 			"       wsr     %1, scompare1\n"		\
 			"       " #op " %0, %1, %2\n"			\
 			"       s32c1i  %0, %3, 0\n"			\
 			"       bne     %0, %1, 1b\n"			\
 			: "=&a" (result), "=&a" (tmp)			\
 			: "a" (i), "a" (v)				\
 			: "memory"					\
 			);						\
 									\
 	return result;							\
 }

 #else /* XCHAL_HAVE_S32C1I */

 #define ATOMIC_OP(op)							\
 static inline void atomic_##op(int i, atomic_t * v)			\
 {									\
 	unsigned int vval;						\
 									\
 	__asm__ __volatile__(						\
 			"       rsil    a15, "__stringify(TOPLEVEL)"\n"\
 			"       l32i    %0, %2, 0\n"			\
 			"       " #op " %0, %0, %1\n"			\
 			"       s32i    %0, %2, 0\n"			\
 			"       wsr     a15, ps\n"			\
 			"       rsync\n"				\
 			: "=&a" (vval)					\
 			: "a" (i), "a" (v)				\
 			: "a15", "memory"				\
 			);						\
 }									\

 #define ATOMIC_OP_RETURN(op)						\
 static inline int atomic_##op##_return(int i, atomic_t * v)		\
 {									\
 	unsigned int vval;						\
 									\
 	__asm__ __volatile__(						\
 			"       rsil    a15,"__stringify(TOPLEVEL)"\n"	\
 			"       l32i    %0, %2, 0\n"			\
 			"       " #op " %0, %0, %1\n"			\
 			"       s32i    %0, %2, 0\n"			\
 			"       wsr     a15, ps\n"			\
 			"       rsync\n"				\
 			: "=&a" (vval)					\
 			: "a" (i), "a" (v)				\
 			: "a15", "memory"				\
 			);						\
 									\
 	return vval;							\
 }

 #define ATOMIC_FETCH_OP(op)						\
 static inline int atomic_fetch_##op(int i, atomic_t * v)		\
 {									\
 	unsigned int tmp, vval;						\
 									\
 	__asm__ __volatile__(						\
 			"       rsil    a15,"__stringify(TOPLEVEL)"\n"	\
 			"       l32i    %0, %3, 0\n"			\
 			"       " #op " %1, %0, %2\n"			\
 			"       s32i    %1, %3, 0\n"			\
 			"       wsr     a15, ps\n"			\
 			"       rsync\n"				\
 			: "=&a" (vval), "=&a" (tmp)			\
 			: "a" (i), "a" (v)				\
 			: "a15", "memory"				\
 			);						\
 									\
 	return vval;							\
 }

 #endif /* XCHAL_HAVE_S32C1I */

 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) ATOMIC_OP_RETURN(op)

 ATOMIC_OPS(add)
 ATOMIC_OPS(sub)

 #undef ATOMIC_OPS
 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)

 ATOMIC_OPS(and)
 ATOMIC_OPS(or)
 ATOMIC_OPS(xor)

 #undef ATOMIC_OPS
 #undef ATOMIC_FETCH_OP
 #undef ATOMIC_OP_RETURN
 #undef ATOMIC_OP

 /**
  * 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 the old value of @v.
  */
 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
 {
 	int c, old;
 	c = atomic_read(v);
 	for (;;) {
 		if (unlikely(c == (u)))
 			break;
 		old = atomic_cmpxchg((v), c, c + (a));
 		if (likely(old == c))
 			break;
 		c = old;
 	}
 	return c;
 }

 #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 - 2008 Tensilica Inc.
	*/

	#ifndef _XTENSA_ATOMIC_H
	#define _XTENSA_ATOMIC_H

	#include <linux/stringify.h>
	#include <linux/types.h>

	#ifdef __KERNEL__
	#include <asm/processor.h>
	#include <asm/cmpxchg.h>
	#include <asm/barrier.h>

	#define ATOMIC_INIT(i) { (i) }

	/*
	* This Xtensa implementation assumes that the right mechanism
	* for exclusion is for locking interrupts to level EXCM_LEVEL.
	*
	* Locking interrupts looks like this:
	*
	* rsil a15, TOPLEVEL
	* <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) READ_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.
	*/
	#define atomic_set(v,i) WRITE_ONCE((v)->counter, (i))

	#if XCHAL_HAVE_S32C1I
	#define ATOMIC_OP(op) \
	static inline void atomic_##op(int i, atomic_t * v) \
	{ \
	unsigned long tmp; \
	int result; \
	\
	__asm__ __volatile__( \
	"1: l32i %1, %3, 0\n" \
	" wsr %1, scompare1\n" \
	" " #op " %0, %1, %2\n" \
	" s32c1i %0, %3, 0\n" \
	" bne %0, %1, 1b\n" \
	: "=&a" (result), "=&a" (tmp) \
	: "a" (i), "a" (v) \
	: "memory" \
	); \
	} \

	#define ATOMIC_OP_RETURN(op) \
	static inline int atomic_##op##_return(int i, atomic_t * v) \
	{ \
	unsigned long tmp; \
	int result; \
	\
	__asm__ __volatile__( \
	"1: l32i %1, %3, 0\n" \
	" wsr %1, scompare1\n" \
	" " #op " %0, %1, %2\n" \
	" s32c1i %0, %3, 0\n" \
	" bne %0, %1, 1b\n" \
	" " #op " %0, %0, %2\n" \
	: "=&a" (result), "=&a" (tmp) \
	: "a" (i), "a" (v) \
	: "memory" \
	); \
	\
	return result; \
	}

	#define ATOMIC_FETCH_OP(op) \
	static inline int atomic_fetch_##op(int i, atomic_t * v) \
	{ \
	unsigned long tmp; \
	int result; \
	\
	__asm__ __volatile__( \
	"1: l32i %1, %3, 0\n" \
	" wsr %1, scompare1\n" \
	" " #op " %0, %1, %2\n" \
	" s32c1i %0, %3, 0\n" \
	" bne %0, %1, 1b\n" \
	: "=&a" (result), "=&a" (tmp) \
	: "a" (i), "a" (v) \
	: "memory" \
	); \
	\
	return result; \
	}

	#else /* XCHAL_HAVE_S32C1I */

	#define ATOMIC_OP(op) \
	static inline void atomic_##op(int i, atomic_t * v) \
	{ \
	unsigned int vval; \
	\
	__asm__ __volatile__( \
	" rsil a15, "__stringify(TOPLEVEL)"\n"\
	" l32i %0, %2, 0\n" \
	" " #op " %0, %0, %1\n" \
	" s32i %0, %2, 0\n" \
	" wsr a15, ps\n" \
	" rsync\n" \
	: "=&a" (vval) \
	: "a" (i), "a" (v) \
	: "a15", "memory" \
	); \
	} \

	#define ATOMIC_OP_RETURN(op) \
	static inline int atomic_##op##_return(int i, atomic_t * v) \
	{ \
	unsigned int vval; \
	\
	__asm__ __volatile__( \
	" rsil a15,"__stringify(TOPLEVEL)"\n" \
	" l32i %0, %2, 0\n" \
	" " #op " %0, %0, %1\n" \
	" s32i %0, %2, 0\n" \
	" wsr a15, ps\n" \
	" rsync\n" \
	: "=&a" (vval) \
	: "a" (i), "a" (v) \
	: "a15", "memory" \
	); \
	\
	return vval; \
	}

	#define ATOMIC_FETCH_OP(op) \
	static inline int atomic_fetch_##op(int i, atomic_t * v) \
	{ \
	unsigned int tmp, vval; \
	\
	__asm__ __volatile__( \
	" rsil a15,"__stringify(TOPLEVEL)"\n" \
	" l32i %0, %3, 0\n" \
	" " #op " %1, %0, %2\n" \
	" s32i %1, %3, 0\n" \
	" wsr a15, ps\n" \
	" rsync\n" \
	: "=&a" (vval), "=&a" (tmp) \
	: "a" (i), "a" (v) \
	: "a15", "memory" \
	); \
	\
	return vval; \
	}

	#endif /* XCHAL_HAVE_S32C1I */

	#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) ATOMIC_OP_RETURN(op)

	ATOMIC_OPS(add)
	ATOMIC_OPS(sub)

	#undef ATOMIC_OPS
	#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)

	ATOMIC_OPS(and)
	ATOMIC_OPS(or)
	ATOMIC_OPS(xor)

	#undef ATOMIC_OPS
	#undef ATOMIC_FETCH_OP
	#undef ATOMIC_OP_RETURN
	#undef ATOMIC_OP

	/**
	* 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 the old value of @v.
	*/
	static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
	{
	int c, old;
	c = atomic_read(v);
	for (;;) {
	if (unlikely(c == (u)))
	break;
	old = atomic_cmpxchg((v), c, c + (a));
	if (likely(old == c))
	break;
	c = old;
	}
	return c;
	}

	#endif /* __KERNEL__ */

	#endif /* _XTENSA_ATOMIC_H */