1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 *
 14 * Atomic primitives.
 15 */
 16
 17#ifndef _ASM_TILE_ATOMIC_H
 18#define _ASM_TILE_ATOMIC_H
 19
 20#ifndef __ASSEMBLY__
 21
 22#include <linux/compiler.h>
 23#include <asm/system.h>
 24
 25#define ATOMIC_INIT(i)	{ (i) }
 26
 27/**
 28 * atomic_read - read atomic variable
 29 * @v: pointer of type atomic_t
 30 *
 31 * Atomically reads the value of @v.
 32 */
 33static inline int atomic_read(const atomic_t *v)
 34{
 35	return ACCESS_ONCE(v->counter);
 36}
 37
 38/**
 39 * atomic_sub_return - subtract integer and return
 40 * @v: pointer of type atomic_t
 41 * @i: integer value to subtract
 42 *
 43 * Atomically subtracts @i from @v and returns @v - @i
 44 */
 45#define atomic_sub_return(i, v)		atomic_add_return((int)(-(i)), (v))
 46
 47/**
 48 * atomic_sub - subtract integer from atomic variable
 49 * @i: integer value to subtract
 50 * @v: pointer of type atomic_t
 51 *
 52 * Atomically subtracts @i from @v.
 53 */
 54#define atomic_sub(i, v)		atomic_add((int)(-(i)), (v))
 55
 56/**
 57 * atomic_sub_and_test - subtract value from variable and test result
 58 * @i: integer value to subtract
 59 * @v: pointer of type atomic_t
 60 *
 61 * Atomically subtracts @i from @v and returns true if the result is
 62 * zero, or false for all other cases.
 63 */
 64#define atomic_sub_and_test(i, v)	(atomic_sub_return((i), (v)) == 0)
 65
 66/**
 67 * atomic_inc_return - increment memory and return
 68 * @v: pointer of type atomic_t
 69 *
 70 * Atomically increments @v by 1 and returns the new value.
 71 */
 72#define atomic_inc_return(v)		atomic_add_return(1, (v))
 73
 74/**
 75 * atomic_dec_return - decrement memory and return
 76 * @v: pointer of type atomic_t
 77 *
 78 * Atomically decrements @v by 1 and returns the new value.
 79 */
 80#define atomic_dec_return(v)		atomic_sub_return(1, (v))
 81
 82/**
 83 * atomic_inc - increment atomic variable
 84 * @v: pointer of type atomic_t
 85 *
 86 * Atomically increments @v by 1.
 87 */
 88#define atomic_inc(v)			atomic_add(1, (v))
 89
 90/**
 91 * atomic_dec - decrement atomic variable
 92 * @v: pointer of type atomic_t
 93 *
 94 * Atomically decrements @v by 1.
 95 */
 96#define atomic_dec(v)			atomic_sub(1, (v))
 97
 98/**
 99 * atomic_dec_and_test - decrement and test
100 * @v: pointer of type atomic_t
101 *
102 * Atomically decrements @v by 1 and returns true if the result is 0.
103 */
104#define atomic_dec_and_test(v)		(atomic_dec_return(v) == 0)
105
106/**
107 * atomic_inc_and_test - increment and test
108 * @v: pointer of type atomic_t
109 *
110 * Atomically increments @v by 1 and returns true if the result is 0.
111 */
112#define atomic_inc_and_test(v)		(atomic_inc_return(v) == 0)
113
114/**
115 * atomic_add_negative - add and test if negative
116 * @v: pointer of type atomic_t
117 * @i: integer value to add
118 *
119 * Atomically adds @i to @v and returns true if the result is
120 * negative, or false when result is greater than or equal to zero.
121 */
122#define atomic_add_negative(i, v)	(atomic_add_return((i), (v)) < 0)
123
124/* Nonexistent functions intended to cause link errors. */
125extern unsigned long __xchg_called_with_bad_pointer(void);
126extern unsigned long __cmpxchg_called_with_bad_pointer(void);
127
128#define xchg(ptr, x)							\
129	({								\
130		typeof(*(ptr)) __x;					\
131		switch (sizeof(*(ptr))) {				\
132		case 4:							\
133			__x = (typeof(__x))(typeof(__x-__x))atomic_xchg( \
134				(atomic_t *)(ptr),			\
135				(u32)(typeof((x)-(x)))(x));		\
136			break;						\
137		case 8:							\
138			__x = (typeof(__x))(typeof(__x-__x))atomic64_xchg( \
139				(atomic64_t *)(ptr),			\
140				(u64)(typeof((x)-(x)))(x));		\
141			break;						\
142		default:						\
143			__xchg_called_with_bad_pointer();		\
144		}							\
145		__x;							\
146	})
147
148#define cmpxchg(ptr, o, n)						\
149	({								\
150		typeof(*(ptr)) __x;					\
151		switch (sizeof(*(ptr))) {				\
152		case 4:							\
153			__x = (typeof(__x))(typeof(__x-__x))atomic_cmpxchg( \
154				(atomic_t *)(ptr),			\
155				(u32)(typeof((o)-(o)))(o),		\
156				(u32)(typeof((n)-(n)))(n));		\
157			break;						\
158		case 8:							\
159			__x = (typeof(__x))(typeof(__x-__x))atomic64_cmpxchg( \
160				(atomic64_t *)(ptr),			\
161				(u64)(typeof((o)-(o)))(o),		\
162				(u64)(typeof((n)-(n)))(n));		\
163			break;						\
164		default:						\
165			__cmpxchg_called_with_bad_pointer();		\
166		}							\
167		__x;							\
168	})
169
170#define tas(ptr) (xchg((ptr), 1))
171
172#endif /* __ASSEMBLY__ */
173
174#ifndef __tilegx__
175#include <asm/atomic_32.h>
176#else
177#include <asm/atomic_64.h>
178#endif
179
180#endif /* _ASM_TILE_ATOMIC_H */