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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-sh/semaphore.h
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'include/asm-sh/semaphore.h')
-rw-r--r--include/asm-sh/semaphore.h119
1 files changed, 119 insertions, 0 deletions
diff --git a/include/asm-sh/semaphore.h b/include/asm-sh/semaphore.h
new file mode 100644
index 00000000000..b923a77a8a7
--- /dev/null
+++ b/include/asm-sh/semaphore.h
@@ -0,0 +1,119 @@
+#ifndef __ASM_SH_SEMAPHORE_H
+#define __ASM_SH_SEMAPHORE_H
+
+#include <linux/linkage.h>
+
+#ifdef __KERNEL__
+/*
+ * SMP- and interrupt-safe semaphores.
+ *
+ * (C) Copyright 1996 Linus Torvalds
+ *
+ * SuperH verison by Niibe Yutaka
+ * (Currently no asm implementation but generic C code...)
+ */
+
+#include <linux/spinlock.h>
+#include <linux/rwsem.h>
+#include <linux/wait.h>
+
+#include <asm/system.h>
+#include <asm/atomic.h>
+
+struct semaphore {
+ atomic_t count;
+ int sleepers;
+ wait_queue_head_t wait;
+};
+
+#define __SEMAPHORE_INITIALIZER(name, n) \
+{ \
+ .count = ATOMIC_INIT(n), \
+ .sleepers = 0, \
+ .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
+}
+
+#define __MUTEX_INITIALIZER(name) \
+ __SEMAPHORE_INITIALIZER(name,1)
+
+#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
+ struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
+
+#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
+#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
+
+static inline void sema_init (struct semaphore *sem, int val)
+{
+/*
+ * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
+ *
+ * i'd rather use the more flexible initialization above, but sadly
+ * GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
+ */
+ atomic_set(&sem->count, val);
+ sem->sleepers = 0;
+ init_waitqueue_head(&sem->wait);
+}
+
+static inline void init_MUTEX (struct semaphore *sem)
+{
+ sema_init(sem, 1);
+}
+
+static inline void init_MUTEX_LOCKED (struct semaphore *sem)
+{
+ sema_init(sem, 0);
+}
+
+#if 0
+asmlinkage void __down_failed(void /* special register calling convention */);
+asmlinkage int __down_failed_interruptible(void /* params in registers */);
+asmlinkage int __down_failed_trylock(void /* params in registers */);
+asmlinkage void __up_wakeup(void /* special register calling convention */);
+#endif
+
+asmlinkage void __down(struct semaphore * sem);
+asmlinkage int __down_interruptible(struct semaphore * sem);
+asmlinkage int __down_trylock(struct semaphore * sem);
+asmlinkage void __up(struct semaphore * sem);
+
+extern spinlock_t semaphore_wake_lock;
+
+static inline void down(struct semaphore * sem)
+{
+ might_sleep();
+ if (atomic_dec_return(&sem->count) < 0)
+ __down(sem);
+}
+
+static inline int down_interruptible(struct semaphore * sem)
+{
+ int ret = 0;
+
+ might_sleep();
+ if (atomic_dec_return(&sem->count) < 0)
+ ret = __down_interruptible(sem);
+ return ret;
+}
+
+static inline int down_trylock(struct semaphore * sem)
+{
+ int ret = 0;
+
+ if (atomic_dec_return(&sem->count) < 0)
+ ret = __down_trylock(sem);
+ return ret;
+}
+
+/*
+ * Note! This is subtle. We jump to wake people up only if
+ * the semaphore was negative (== somebody was waiting on it).
+ */
+static inline void up(struct semaphore * sem)
+{
+ if (atomic_inc_return(&sem->count) <= 0)
+ __up(sem);
+}
+
+#endif
+#endif /* __ASM_SH_SEMAPHORE_H */