File: /usr/src/linux/include/asm-m68k/semaphore.h
1 #ifndef _M68K_SEMAPHORE_H
2 #define _M68K_SEMAPHORE_H
3
4 #define RW_LOCK_BIAS 0x01000000
5
6 #ifndef __ASSEMBLY__
7
8 #include <linux/linkage.h>
9 #include <linux/wait.h>
10 #include <linux/spinlock.h>
11 #include <linux/rwsem.h>
12
13 #include <asm/system.h>
14 #include <asm/atomic.h>
15
16 /*
17 * Interrupt-safe semaphores..
18 *
19 * (C) Copyright 1996 Linus Torvalds
20 *
21 * m68k version by Andreas Schwab
22 */
23
24
25 struct semaphore {
26 atomic_t count;
27 atomic_t waking;
28 wait_queue_head_t wait;
29 #if WAITQUEUE_DEBUG
30 long __magic;
31 #endif
32 };
33
34 #if WAITQUEUE_DEBUG
35 # define __SEM_DEBUG_INIT(name) \
36 , (long)&(name).__magic
37 #else
38 # define __SEM_DEBUG_INIT(name)
39 #endif
40
41 #define __SEMAPHORE_INITIALIZER(name,count) \
42 { ATOMIC_INIT(count), ATOMIC_INIT(0), __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
43 __SEM_DEBUG_INIT(name) }
44
45 #define __MUTEX_INITIALIZER(name) \
46 __SEMAPHORE_INITIALIZER(name,1)
47
48 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
49 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
50
51 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
52 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
53
54 extern inline void sema_init (struct semaphore *sem, int val)
55 {
56 *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
57 }
58
59 static inline void init_MUTEX (struct semaphore *sem)
60 {
61 sema_init(sem, 1);
62 }
63
64 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
65 {
66 sema_init(sem, 0);
67 }
68
69 asmlinkage void __down_failed(void /* special register calling convention */);
70 asmlinkage int __down_failed_interruptible(void /* params in registers */);
71 asmlinkage int __down_failed_trylock(void /* params in registers */);
72 asmlinkage void __up_wakeup(void /* special register calling convention */);
73
74 asmlinkage void __down(struct semaphore * sem);
75 asmlinkage int __down_interruptible(struct semaphore * sem);
76 asmlinkage int __down_trylock(struct semaphore * sem);
77 asmlinkage void __up(struct semaphore * sem);
78
79 /*
80 * This is ugly, but we want the default case to fall through.
81 * "down_failed" is a special asm handler that calls the C
82 * routine that actually waits. See arch/m68k/lib/semaphore.S
83 */
84 extern inline void down(struct semaphore * sem)
85 {
86 register struct semaphore *sem1 __asm__ ("%a1") = sem;
87
88 #if WAITQUEUE_DEBUG
89 CHECK_MAGIC(sem->__magic);
90 #endif
91
92 __asm__ __volatile__(
93 "| atomic down operation\n\t"
94 "subql #1,%0@\n\t"
95 "jmi 2f\n\t"
96 "1:\n"
97 ".section .text.lock,\"ax\"\n"
98 ".even\n"
99 "2:\tpea 1b\n\t"
100 "jbra __down_failed\n"
101 ".previous"
102 : /* no outputs */
103 : "a" (sem1)
104 : "memory");
105 }
106
107 extern inline int down_interruptible(struct semaphore * sem)
108 {
109 register struct semaphore *sem1 __asm__ ("%a1") = sem;
110 register int result __asm__ ("%d0");
111
112 #if WAITQUEUE_DEBUG
113 CHECK_MAGIC(sem->__magic);
114 #endif
115
116 __asm__ __volatile__(
117 "| atomic interruptible down operation\n\t"
118 "subql #1,%1@\n\t"
119 "jmi 2f\n\t"
120 "clrl %0\n"
121 "1:\n"
122 ".section .text.lock,\"ax\"\n"
123 ".even\n"
124 "2:\tpea 1b\n\t"
125 "jbra __down_failed_interruptible\n"
126 ".previous"
127 : "=d" (result)
128 : "a" (sem1)
129 : "%d0", "memory");
130 return result;
131 }
132
133 extern inline int down_trylock(struct semaphore * sem)
134 {
135 register struct semaphore *sem1 __asm__ ("%a1") = sem;
136 register int result __asm__ ("%d0");
137
138 #if WAITQUEUE_DEBUG
139 CHECK_MAGIC(sem->__magic);
140 #endif
141
142 __asm__ __volatile__(
143 "| atomic down trylock operation\n\t"
144 "subql #1,%1@\n\t"
145 "jmi 2f\n\t"
146 "clrl %0\n"
147 "1:\n"
148 ".section .text.lock,\"ax\"\n"
149 ".even\n"
150 "2:\tpea 1b\n\t"
151 "jbra __down_failed_trylock\n"
152 ".previous"
153 : "=d" (result)
154 : "a" (sem1)
155 : "%d0", "memory");
156 return result;
157 }
158
159 /*
160 * Note! This is subtle. We jump to wake people up only if
161 * the semaphore was negative (== somebody was waiting on it).
162 * The default case (no contention) will result in NO
163 * jumps for both down() and up().
164 */
165 extern inline void up(struct semaphore * sem)
166 {
167 register struct semaphore *sem1 __asm__ ("%a1") = sem;
168
169 #if WAITQUEUE_DEBUG
170 CHECK_MAGIC(sem->__magic);
171 #endif
172
173 __asm__ __volatile__(
174 "| atomic up operation\n\t"
175 "addql #1,%0@\n\t"
176 "jle 2f\n"
177 "1:\n"
178 ".section .text.lock,\"ax\"\n"
179 ".even\n"
180 "2:\t"
181 "pea 1b\n\t"
182 "jbra __up_wakeup\n"
183 ".previous"
184 : /* no outputs */
185 : "a" (sem1)
186 : "memory");
187 }
188
189 #endif /* __ASSEMBLY__ */
190
191 #endif
192