[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6

The attached patches provides part 6 of an architecture implementation for the
Tensilica Xtensa CPU series.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 129 insertions, 0 deletions

diff --git a/include/asm-xtensa/semaphore.h b/include/asm-xtensa/semaphore.h
new file mode 100644
index 000000000000..c8a7574a9a57
--- /dev/null
+++ b/include/asm-xtensa/semaphore.h
@@ -0,0 +1,129 @@
+/*
+ * linux/include/asm-xtensa/semaphore.h
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001 - 2005 Tensilica Inc.
+ */
+
+#ifndef _XTENSA_SEMAPHORE_H
+#define _XTENSA_SEMAPHORE_H
+
+#include <asm/atomic.h>
+#include <asm/system.h>
+#include <linux/wait.h>
+#include <linux/rwsem.h>
+
+struct semaphore {
+        atomic_t count;
+        int sleepers;
+        wait_queue_head_t wait;
+#if WAITQUEUE_DEBUG
+        long __magic;
+#endif
+};
+
+#if WAITQUEUE_DEBUG
+# define __SEM_DEBUG_INIT(name) \
+                , (int)&(name).__magic
+#else
+# define __SEM_DEBUG_INIT(name)
+#endif
+
+#define __SEMAPHORE_INITIALIZER(name,count)                     \
+        { ATOMIC_INIT(count),                                   \
+          0,                                                    \
+          __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)            \
+        __SEM_DEBUG_INIT(name) }
+
+#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);
+ *
+ * i'd rather use the more flexible initialization above, but sadly
+ * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well.
+ */
+        atomic_set(&sem->count, val);
+        init_waitqueue_head(&sem->wait);
+#if WAITQUEUE_DEBUG
+        sem->__magic = (int)&sem->__magic;
+#endif
+}
+
+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(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;
+
+extern __inline__ void down(struct semaphore * sem)
+{
+#if WAITQUEUE_DEBUG
+        CHECK_MAGIC(sem->__magic);
+#endif
+
+        if (atomic_sub_return(1, &sem->count) < 0)
+                __down(sem);
+}
+
+extern __inline__ int down_interruptible(struct semaphore * sem)
+{
+        int ret = 0;
+#if WAITQUEUE_DEBUG
+        CHECK_MAGIC(sem->__magic);
+#endif
+
+        if (atomic_sub_return(1, &sem->count) < 0)
+                ret = __down_interruptible(sem);
+        return ret;
+}
+
+extern __inline__ int down_trylock(struct semaphore * sem)
+{
+        int ret = 0;
+#if WAITQUEUE_DEBUG
+        CHECK_MAGIC(sem->__magic);
+#endif
+
+        if (atomic_sub_return(1, &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).
+ */
+extern __inline__ void up(struct semaphore * sem)
+{
+#if WAITQUEUE_DEBUG
+        CHECK_MAGIC(sem->__magic);
+#endif
+        if (atomic_add_return(1, &sem->count) <= 0)
+                __up(sem);
+}
+
+#endif /* _XTENSA_SEMAPHORE_H */