From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@ppc970.osdl.org>
Date: Sat, 16 Apr 2005 15:20:36 -0700
Subject: Linux-2.6.12-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!
---
 include/asm-cris/semaphore.h | 142 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 include/asm-cris/semaphore.h

(limited to 'include/asm-cris/semaphore.h')

diff --git a/include/asm-cris/semaphore.h b/include/asm-cris/semaphore.h
new file mode 100644
index 0000000..605aa7e
--- /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
-- 
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