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 * Do not include directly; use <linux/atomic.h>.
15 */
16
17#ifndef _ASM_TILE_ATOMIC_32_H
18#define _ASM_TILE_ATOMIC_32_H
19
20#include <asm/barrier.h>
21#include <arch/chip.h>
22
23#ifndef __ASSEMBLY__
24
25/**
26 * atomic_add - add integer to atomic variable
27 * @i: integer value to add
28 * @v: pointer of type atomic_t
29 *
30 * Atomically adds @i to @v.
31 */
32static inline void atomic_add(int i, atomic_t *v)
33{
34	_atomic_xchg_add(&v->counter, i);
35}
36
37/**
38 * atomic_add_return - add integer and return
39 * @v: pointer of type atomic_t
40 * @i: integer value to add
41 *
42 * Atomically adds @i to @v and returns @i + @v
43 */
44static inline int atomic_add_return(int i, atomic_t *v)
45{
46	smp_mb();  /* barrier for proper semantics */
47	return _atomic_xchg_add(&v->counter, i) + i;
48}
49
50/**
51 * __atomic_add_unless - add unless the number is already a given value
52 * @v: pointer of type atomic_t
53 * @a: the amount to add to v...
54 * @u: ...unless v is equal to u.
55 *
56 * Atomically adds @a to @v, so long as @v was not already @u.
57 * Returns the old value of @v.
58 */
59static inline int __atomic_add_unless(atomic_t *v, int a, int u)
60{
61	smp_mb();  /* barrier for proper semantics */
62	return _atomic_xchg_add_unless(&v->counter, a, u);
63}
64
65/**
66 * atomic_set - set atomic variable
67 * @v: pointer of type atomic_t
68 * @i: required value
69 *
70 * Atomically sets the value of @v to @i.
71 *
72 * atomic_set() can't be just a raw store, since it would be lost if it
73 * fell between the load and store of one of the other atomic ops.
74 */
75static inline void atomic_set(atomic_t *v, int n)
76{
77	_atomic_xchg(&v->counter, n);
78}
79
80/* A 64bit atomic type */
81
82typedef struct {
83	long long counter;
84} atomic64_t;
85
86#define ATOMIC64_INIT(val) { (val) }
87
88/**
89 * atomic64_read - read atomic variable
90 * @v: pointer of type atomic64_t
91 *
92 * Atomically reads the value of @v.
93 */
94static inline long long atomic64_read(const atomic64_t *v)
95{
96	/*
97	 * Requires an atomic op to read both 32-bit parts consistently.
98	 * Casting away const is safe since the atomic support routines
99	 * do not write to memory if the value has not been modified.
100	 */
101	return _atomic64_xchg_add((long long *)&v->counter, 0);
102}
103
104/**
105 * atomic64_add - add integer to atomic variable
106 * @i: integer value to add
107 * @v: pointer of type atomic64_t
108 *
109 * Atomically adds @i to @v.
110 */
111static inline void atomic64_add(long long i, atomic64_t *v)
112{
113	_atomic64_xchg_add(&v->counter, i);
114}
115
116/**
117 * atomic64_add_return - add integer and return
118 * @v: pointer of type atomic64_t
119 * @i: integer value to add
120 *
121 * Atomically adds @i to @v and returns @i + @v
122 */
123static inline long long atomic64_add_return(long long i, atomic64_t *v)
124{
125	smp_mb();  /* barrier for proper semantics */
126	return _atomic64_xchg_add(&v->counter, i) + i;
127}
128
129/**
130 * atomic64_add_unless - add unless the number is already a given value
131 * @v: pointer of type atomic64_t
132 * @a: the amount to add to v...
133 * @u: ...unless v is equal to u.
134 *
135 * Atomically adds @a to @v, so long as @v was not already @u.
136 * Returns non-zero if @v was not @u, and zero otherwise.
137 */
138static inline long long atomic64_add_unless(atomic64_t *v, long long a,
139					long long u)
140{
141	smp_mb();  /* barrier for proper semantics */
142	return _atomic64_xchg_add_unless(&v->counter, a, u) != u;
143}
144
145/**
146 * atomic64_set - set atomic variable
147 * @v: pointer of type atomic64_t
148 * @i: required value
149 *
150 * Atomically sets the value of @v to @i.
151 *
152 * atomic64_set() can't be just a raw store, since it would be lost if it
153 * fell between the load and store of one of the other atomic ops.
154 */
155static inline void atomic64_set(atomic64_t *v, long long n)
156{
157	_atomic64_xchg(&v->counter, n);
158}
159
160#define atomic64_add_negative(a, v)	(atomic64_add_return((a), (v)) < 0)
161#define atomic64_inc(v)			atomic64_add(1LL, (v))
162#define atomic64_inc_return(v)		atomic64_add_return(1LL, (v))
163#define atomic64_inc_and_test(v)	(atomic64_inc_return(v) == 0)
164#define atomic64_sub_return(i, v)	atomic64_add_return(-(i), (v))
165#define atomic64_sub_and_test(a, v)	(atomic64_sub_return((a), (v)) == 0)
166#define atomic64_sub(i, v)		atomic64_add(-(i), (v))
167#define atomic64_dec(v)			atomic64_sub(1LL, (v))
168#define atomic64_dec_return(v)		atomic64_sub_return(1LL, (v))
169#define atomic64_dec_and_test(v)	(atomic64_dec_return((v)) == 0)
170#define atomic64_inc_not_zero(v)	atomic64_add_unless((v), 1LL, 0LL)
171
172
173#endif /* !__ASSEMBLY__ */
174
175/*
176 * Internal definitions only beyond this point.
177 */
178
179/*
180 * Number of atomic locks in atomic_locks[]. Must be a power of two.
181 * There is no reason for more than PAGE_SIZE / 8 entries, since that
182 * is the maximum number of pointer bits we can use to index this.
183 * And we cannot have more than PAGE_SIZE / 4, since this has to
184 * fit on a single page and each entry takes 4 bytes.
185 */
186#define ATOMIC_HASH_SHIFT (PAGE_SHIFT - 3)
187#define ATOMIC_HASH_SIZE (1 << ATOMIC_HASH_SHIFT)
188
189#ifndef __ASSEMBLY__
190extern int atomic_locks[];
191#endif
192
193/*
194 * All the code that may fault while holding an atomic lock must
195 * place the pointer to the lock in ATOMIC_LOCK_REG so the fault code
196 * can correctly release and reacquire the lock.  Note that we
197 * mention the register number in a comment in "lib/atomic_asm.S" to help
198 * assembly coders from using this register by mistake, so if it
199 * is changed here, change that comment as well.
200 */
201#define ATOMIC_LOCK_REG 20
202#define ATOMIC_LOCK_REG_NAME r20
203
204#ifndef __ASSEMBLY__
205/* Called from setup to initialize a hash table to point to per_cpu locks. */
206void __init_atomic_per_cpu(void);
207
208#ifdef CONFIG_SMP
209/* Support releasing the atomic lock in do_page_fault_ics(). */
210void __atomic_fault_unlock(int *lock_ptr);
211#endif
212
213/* Return a pointer to the lock for the given address. */
214int *__atomic_hashed_lock(volatile void *v);
215
216/* Private helper routines in lib/atomic_asm_32.S */
217struct __get_user {
218	unsigned long val;
219	int err;
220};
221extern struct __get_user __atomic_cmpxchg(volatile int *p,
222					  int *lock, int o, int n);
223extern struct __get_user __atomic_xchg(volatile int *p, int *lock, int n);
224extern struct __get_user __atomic_xchg_add(volatile int *p, int *lock, int n);
225extern struct __get_user __atomic_xchg_add_unless(volatile int *p,
226						  int *lock, int o, int n);
227extern struct __get_user __atomic_or(volatile int *p, int *lock, int n);
228extern struct __get_user __atomic_andn(volatile int *p, int *lock, int n);
229extern struct __get_user __atomic_xor(volatile int *p, int *lock, int n);
230extern long long __atomic64_cmpxchg(volatile long long *p, int *lock,
231					long long o, long long n);
232extern long long __atomic64_xchg(volatile long long *p, int *lock, long long n);
233extern long long __atomic64_xchg_add(volatile long long *p, int *lock,
234					long long n);
235extern long long __atomic64_xchg_add_unless(volatile long long *p,
236					int *lock, long long o, long long n);
237
238/* Return failure from the atomic wrappers. */
239struct __get_user __atomic_bad_address(int __user *addr);
240
241#endif /* !__ASSEMBLY__ */
242
243#endif /* _ASM_TILE_ATOMIC_32_H */
244