1 files changed, 142 insertions, 0 deletions
diff --git a/include/asm-cris/semaphore.h b/include/asm-cris/semaphore.h
new file mode 100644
index 00000000000..605aa7eaaaf
--- /dev/null
+++ b/include/asm-cris/semaphore.h
@@ -0,0 +1,142 @@
+/* $Id: semaphore.h,v 1.3 2001/05/08 13:54:09 bjornw Exp $ */
+
+/* On the i386 these are coded in asm, perhaps we should as well. Later.. */
+
+#ifndef _CRIS_SEMAPHORE_H
+#define _CRIS_SEMAPHORE_H
+
+#define RW_LOCK_BIAS             0x01000000
+
+#include <linux/wait.h>
+#include <linux/spinlock.h>
+#include <linux/rwsem.h>
+
+#include <asm/system.h>
+#include <asm/atomic.h>
+
+/*
+ * CRIS semaphores, implemented in C-only so far. 
+ */
+
+int printk(const char *fmt, ...);
+
+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);
+}
+
+extern inline void init_MUTEX (struct semaphore *sem)
+{
+        sema_init(sem, 1);
+}
+
+extern inline void init_MUTEX_LOCKED (struct semaphore *sem)
+{
+        sema_init(sem, 0);
+}
+
+extern void __down(struct semaphore * sem);
+extern int __down_interruptible(struct semaphore * sem);
+extern int __down_trylock(struct semaphore * sem);
+extern void __up(struct semaphore * sem);
+
+/* notice - we probably can do cli/sti here instead of saving */
+
+extern inline void down(struct semaphore * sem)
+{
+	unsigned long flags;
+	int failed;
+
+	might_sleep();
+
+	/* atomically decrement the semaphores count, and if its negative, we wait */
+	local_save_flags(flags);
+	local_irq_disable();
+	failed = --(sem->count.counter) < 0;
+	local_irq_restore(flags);
+	if(failed) {
+		__down(sem);
+	}
+}
+
+/*
+ * This version waits in interruptible state so that the waiting
+ * process can be killed.  The down_interruptible routine
+ * returns negative for signalled and zero for semaphore acquired.
+ */
+
+extern inline int down_interruptible(struct semaphore * sem)
+{
+	unsigned long flags;
+	int failed;
+
+	might_sleep();
+
+	/* atomically decrement the semaphores count, and if its negative, we wait */
+	local_save_flags(flags);
+	local_irq_disable();
+	failed = --(sem->count.counter) < 0;
+	local_irq_restore(flags);
+	if(failed)
+		failed = __down_interruptible(sem);
+	return(failed);
+}
+
+extern inline int down_trylock(struct semaphore * sem)
+{
+	unsigned long flags;
+	int failed;
+
+	local_save_flags(flags);
+	local_irq_disable();
+	failed = --(sem->count.counter) < 0;
+	local_irq_restore(flags);
+	if(failed)
+		failed = __down_trylock(sem);
+	return(failed);
+}
+
+/*
+ * 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)
+{  
+	unsigned long flags;
+	int wakeup;
+
+	/* atomically increment the semaphores count, and if it was negative, we wake people */
+	local_save_flags(flags);
+	local_irq_disable();
+	wakeup = ++(sem->count.counter) <= 0;
+	local_irq_restore(flags);
+	if(wakeup) {
+		__up(sem);
+	}
+}
+
+#endif