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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-m68knommu/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-m68knommu/semaphore.h')
-rw-r--r--include/asm-m68knommu/semaphore.h157
1 files changed, 157 insertions, 0 deletions
diff --git a/include/asm-m68knommu/semaphore.h b/include/asm-m68knommu/semaphore.h
new file mode 100644
index 000000000000..febe85add509
--- /dev/null
+++ b/include/asm-m68knommu/semaphore.h
@@ -0,0 +1,157 @@
+#ifndef _M68K_SEMAPHORE_H
+#define _M68K_SEMAPHORE_H
+
+#define RW_LOCK_BIAS 0x01000000
+
+#ifndef __ASSEMBLY__
+
+#include <linux/linkage.h>
+#include <linux/wait.h>
+#include <linux/spinlock.h>
+#include <linux/rwsem.h>
+
+#include <asm/system.h>
+#include <asm/atomic.h>
+
+/*
+ * Interrupt-safe semaphores..
+ *
+ * (C) Copyright 1996 Linus Torvalds
+ *
+ * m68k version by Andreas Schwab
+ */
+
+
+struct semaphore {
+ atomic_t count;
+ atomic_t waking;
+ wait_queue_head_t wait;
+};
+
+#define __SEMAPHORE_INITIALIZER(name, n) \
+{ \
+ .count = ATOMIC_INIT(n), \
+ .waking = ATOMIC_INIT(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)
+
+extern inline void sema_init (struct semaphore *sem, int val)
+{
+ *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
+}
+
+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);
+}
+
+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 */);
+
+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;
+
+/*
+ * This is ugly, but we want the default case to fall through.
+ * "down_failed" is a special asm handler that calls the C
+ * routine that actually waits. See arch/m68k/lib/semaphore.S
+ */
+extern inline void down(struct semaphore * sem)
+{
+ might_sleep();
+ __asm__ __volatile__(
+ "| atomic down operation\n\t"
+ "movel %0, %%a1\n\t"
+ "lea %%pc@(1f), %%a0\n\t"
+ "subql #1, %%a1@\n\t"
+ "jmi __down_failed\n"
+ "1:"
+ : /* no outputs */
+ : "g" (sem)
+ : "cc", "%a0", "%a1", "memory");
+}
+
+extern inline int down_interruptible(struct semaphore * sem)
+{
+ int ret;
+
+ might_sleep();
+ __asm__ __volatile__(
+ "| atomic down operation\n\t"
+ "movel %1, %%a1\n\t"
+ "lea %%pc@(1f), %%a0\n\t"
+ "subql #1, %%a1@\n\t"
+ "jmi __down_failed_interruptible\n\t"
+ "clrl %%d0\n"
+ "1: movel %%d0, %0\n"
+ : "=d" (ret)
+ : "g" (sem)
+ : "cc", "%d0", "%a0", "%a1", "memory");
+ return(ret);
+}
+
+extern inline int down_trylock(struct semaphore * sem)
+{
+ register struct semaphore *sem1 __asm__ ("%a1") = sem;
+ register int result __asm__ ("%d0");
+
+ __asm__ __volatile__(
+ "| atomic down trylock operation\n\t"
+ "subql #1,%1@\n\t"
+ "jmi 2f\n\t"
+ "clrl %0\n"
+ "1:\n"
+ ".section .text.lock,\"ax\"\n"
+ ".even\n"
+ "2:\tpea 1b\n\t"
+ "jbra __down_failed_trylock\n"
+ ".previous"
+ : "=d" (result)
+ : "a" (sem1)
+ : "memory");
+ return result;
+}
+
+/*
+ * Note! This is subtle. We jump to wake people up only if
+ * the semaphore was negative (== somebody was waiting on it).
+ * The default case (no contention) will result in NO
+ * jumps for both down() and up().
+ */
+extern inline void up(struct semaphore * sem)
+{
+ __asm__ __volatile__(
+ "| atomic up operation\n\t"
+ "movel %0, %%a1\n\t"
+ "lea %%pc@(1f), %%a0\n\t"
+ "addql #1, %%a1@\n\t"
+ "jle __up_wakeup\n"
+ "1:"
+ : /* no outputs */
+ : "g" (sem)
+ : "cc", "%a0", "%a1", "memory");
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif