[deliverable/linux.git] / include / asm-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.
 */
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 != (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 */
Commit	Line	Data
9a8fd558 CZ	1	/*
	2	* include/asm-xtensa/atomic.h
	3	*
	4	* Atomic operations that C can't guarantee us. Useful for resource counting..
	5	*
	6	* This file is subject to the terms and conditions of the GNU General Public
	7	* License. See the file "COPYING" in the main directory of this archive
	8	* for more details.
	9	*
	10	* Copyright (C) 2001 - 2005 Tensilica Inc.
	11	*/
	12
	13	#ifndef _XTENSA_ATOMIC_H
	14	#define _XTENSA_ATOMIC_H
	15
9a8fd558 CZ	16	#include <linux/stringify.h>
	17
	18	typedef struct { volatile int counter; } atomic_t;
	19
	20	#ifdef __KERNEL__
	21	#include <asm/processor.h>
	22	#include <asm/system.h>
	23
288a60cf	24	#define ATOMIC_INIT(i) { (i) }
9a8fd558 CZ	25
	26	/*
	27	* This Xtensa implementation assumes that the right mechanism
	28	* for exclusion is for locking interrupts to level 1.
	29	*
	30	* Locking interrupts looks like this:
	31	*
	32	* rsil a15, 1
	33	* <code>
	34	* wsr a15, PS
	35	* rsync
	36	*
	37	* Note that a15 is used here because the register allocation
	38	* done by the compiler is not guaranteed and a window overflow
	39	* may not occur between the rsil and wsr instructions. By using
	40	* a15 in the rsil, the machine is guaranteed to be in a state
	41	* where no register reference will cause an overflow.
	42	*/
	43
	44	/**
	45	* atomic_read - read atomic variable
	46	* @v: pointer of type atomic_t
	47	*
	48	* Atomically reads the value of @v.
	49	*/
	50	#define atomic_read(v) ((v)->counter)
	51
	52	/**
	53	* atomic_set - set atomic variable
	54	* @v: pointer of type atomic_t
	55	* @i: required value
	56	*
	57	* Atomically sets the value of @v to @i.
	58	*/
	59	#define atomic_set(v,i) ((v)->counter = (i))
	60
	61	/**
	62	* atomic_add - add integer to atomic variable
	63	* @i: integer value to add
	64	* @v: pointer of type atomic_t
	65	*
	66	* Atomically adds @i to @v.
	67	*/
d99cf715	68	static inline void atomic_add(int i, atomic_t * v)
9a8fd558 CZ	69	{
	70	unsigned int vval;
	71
	72	__asm__ __volatile__(
	73	"rsil a15, "__stringify(LOCKLEVEL)"\n\t"
	74	"l32i %0, %2, 0 \n\t"
	75	"add %0, %0, %1 \n\t"
	76	"s32i %0, %2, 0 \n\t"
	77	"wsr a15, "__stringify(PS)" \n\t"
	78	"rsync \n"
	79	: "=&a" (vval)
	80	: "a" (i), "a" (v)
	81	: "a15", "memory"
	82	);
	83	}
	84
	85	/**
	86	* atomic_sub - subtract the atomic variable
	87	* @i: integer value to subtract
	88	* @v: pointer of type atomic_t
	89	*
	90	* Atomically subtracts @i from @v.
	91	*/
d99cf715	92	static inline void atomic_sub(int i, atomic_t *v)
9a8fd558 CZ	93	{
	94	unsigned int vval;
	95
	96	__asm__ __volatile__(
	97	"rsil a15, "__stringify(LOCKLEVEL)"\n\t"
	98	"l32i %0, %2, 0 \n\t"
	99	"sub %0, %0, %1 \n\t"
	100	"s32i %0, %2, 0 \n\t"
	101	"wsr a15, "__stringify(PS)" \n\t"
	102	"rsync \n"
	103	: "=&a" (vval)
	104	: "a" (i), "a" (v)
	105	: "a15", "memory"
	106	);
	107	}
	108
	109	/*
	110	* We use atomic_{add\|sub}_return to define other functions.
	111	*/
	112
d99cf715	113	static inline int atomic_add_return(int i, atomic_t * v)
9a8fd558 CZ	114	{
	115	unsigned int vval;
	116
	117	__asm__ __volatile__(
	118	"rsil a15,"__stringify(LOCKLEVEL)"\n\t"
	119	"l32i %0, %2, 0 \n\t"
	120	"add %0, %0, %1 \n\t"
	121	"s32i %0, %2, 0 \n\t"
	122	"wsr a15, "__stringify(PS)" \n\t"
	123	"rsync \n"
	124	: "=&a" (vval)
	125	: "a" (i), "a" (v)
	126	: "a15", "memory"
	127	);
	128
	129	return vval;
	130	}
	131
d99cf715	132	static inline int atomic_sub_return(int i, atomic_t * v)
9a8fd558 CZ	133	{
	134	unsigned int vval;
	135
	136	__asm__ __volatile__(
	137	"rsil a15,"__stringify(LOCKLEVEL)"\n\t"
	138	"l32i %0, %2, 0 \n\t"
	139	"sub %0, %0, %1 \n\t"
	140	"s32i %0, %2, 0 \n\t"
	141	"wsr a15, "__stringify(PS)" \n\t"
	142	"rsync \n"
	143	: "=&a" (vval)
	144	: "a" (i), "a" (v)
	145	: "a15", "memory"
	146	);
	147
	148	return vval;
	149	}
	150
	151	/**
	152	* atomic_sub_and_test - subtract value from variable and test result
	153	* @i: integer value to subtract
	154	* @v: pointer of type atomic_t
	155	*
	156	* Atomically subtracts @i from @v and returns
	157	* true if the result is zero, or false for all
	158	* other cases.
	159	*/
	160	#define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0)
	161
	162	/**
	163	* atomic_inc - increment atomic variable
	164	* @v: pointer of type atomic_t
	165	*
	166	* Atomically increments @v by 1.
	167	*/
	168	#define atomic_inc(v) atomic_add(1,(v))
	169
	170	/**
	171	* atomic_inc - increment atomic variable
	172	* @v: pointer of type atomic_t
	173	*
	174	* Atomically increments @v by 1.
	175	*/
	176	#define atomic_inc_return(v) atomic_add_return(1,(v))
	177
	178	/**
	179	* atomic_dec - decrement atomic variable
	180	* @v: pointer of type atomic_t
	181	*
	182	* Atomically decrements @v by 1.
	183	*/
	184	#define atomic_dec(v) atomic_sub(1,(v))
	185
	186	/**
	187	* atomic_dec_return - decrement atomic variable
	188	* @v: pointer of type atomic_t
	189	*
	190	* Atomically decrements @v by 1.
	191	*/
	192	#define atomic_dec_return(v) atomic_sub_return(1,(v))
	193
	194	/**
	195	* atomic_dec_and_test - decrement and test
	196	* @v: pointer of type atomic_t
197	*
198	* Atomically decrements @v by 1 and
199	* returns true if the result is 0, or false for all other
200	* cases.
201	*/
202	#define atomic_dec_and_test(v) (atomic_sub_return(1,(v)) == 0)
203
204	/**
205	* atomic_inc_and_test - increment and test
206	* @v: pointer of type atomic_t
207	*
208	* Atomically increments @v by 1
209	* and returns true if the result is zero, or false for all
210	* other cases.
211	*/
212	#define atomic_inc_and_test(v) (atomic_add_return(1,(v)) == 0)
213
214	/**
215	* atomic_add_negative - add and test if negative
216	* @v: pointer of type atomic_t
217	* @i: integer value to add
218	*
219	* Atomically adds @i to @v and returns true
220	* if the result is negative, or false when
221	* result is greater than or equal to zero.
222	*/
223	#define atomic_add_negative(i,v) (atomic_add_return((i),(v)) < 0)
224
4a6dae6d	225	#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
ffbf670f	226	#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
9a8fd558	227
8426e1f6 NP	228	/**
	229	* atomic_add_unless - add unless the number is a given value
	230	* @v: pointer of type atomic_t
	231	* @a: the amount to add to v...
	232	* @u: ...unless v is equal to u.
	233	*
	234	* Atomically adds @a to @v, so long as it was not @u.
	235	* Returns non-zero if @v was not @u, and zero otherwise.
	236	*/
2856f5e3 MD	237	static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
	238	{
	239	int c, old;
	240	c = atomic_read(v);
	241	for (;;) {
	242	if (unlikely(c == (u)))
	243	break;
	244	old = atomic_cmpxchg((v), c, c + (a));
	245	if (likely(old == c))
	246	break;
	247	c = old;
	248	}
	249	return c != (u);
	250	}
	251
8426e1f6 NP	252	#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
8426e1f6 NP	253
d99cf715	254	static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
9a8fd558 CZ	255	{
	256	unsigned int all_f = -1;
	257	unsigned int vval;
	258
	259	__asm__ __volatile__(
	260	"rsil a15,"__stringify(LOCKLEVEL)"\n\t"
	261	"l32i %0, %2, 0 \n\t"
	262	"xor %1, %4, %3 \n\t"
	263	"and %0, %0, %4 \n\t"
	264	"s32i %0, %2, 0 \n\t"
	265	"wsr a15, "__stringify(PS)" \n\t"
	266	"rsync \n"
	267	: "=&a" (vval), "=a" (mask)
	268	: "a" (v), "a" (all_f), "1" (mask)
	269	: "a15", "memory"
	270	);
	271	}
	272
d99cf715	273	static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
9a8fd558 CZ	274	{
	275	unsigned int vval;
	276
	277	__asm__ __volatile__(
	278	"rsil a15,"__stringify(LOCKLEVEL)"\n\t"
	279	"l32i %0, %2, 0 \n\t"
	280	"or %0, %0, %1 \n\t"
	281	"s32i %0, %2, 0 \n\t"
	282	"wsr a15, "__stringify(PS)" \n\t"
	283	"rsync \n"
	284	: "=&a" (vval)
	285	: "a" (mask), "a" (v)
	286	: "a15", "memory"
	287	);
	288	}
	289
	290	/* Atomic operations are already serializing */
	291	#define smp_mb__before_atomic_dec() barrier()
	292	#define smp_mb__after_atomic_dec() barrier()
	293	#define smp_mb__before_atomic_inc() barrier()
	294	#define smp_mb__after_atomic_inc() barrier()
	295
d3cb4871	296	#include <asm-generic/atomic.h>
9a8fd558 CZ	297	#endif /* __KERNEL__ */
	298
	299	#endif /* _XTENSA_ATOMIC_H */
	300