1 files changed, 165 insertions, 0 deletions

diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
new file mode 100644
index 000000000000..c99c64dc5f3d
--- /dev/null
+++ b/include/asm-generic/atomic.h
@@ -0,0 +1,165 @@
+/*
+ * Generic C implementation of atomic counter operations
+ * Originally implemented for MN10300.
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#ifndef __ASM_GENERIC_ATOMIC_H
+#define __ASM_GENERIC_ATOMIC_H
+
+#ifdef CONFIG_SMP
+#error not SMP safe
+#endif
+
+/*
+ * Atomic operations that C can't guarantee us.  Useful for
+ * resource counting etc..
+ */
+
+#define ATOMIC_INIT(i)  { (i) }
+
+#ifdef __KERNEL__
+
+/**
+ * atomic_read - read atomic variable
+ * @v: pointer of type atomic_t
+ *
+ * Atomically reads the value of @v.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */
+#define atomic_read(v)  ((v)->counter)
+
+/**
+ * atomic_set - set atomic variable
+ * @v: pointer of type atomic_t
+ * @i: required value
+ *
+ * Atomically sets the value of @v to @i.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */
+#define atomic_set(v, i) (((v)->counter) = (i))
+
+#include <asm/system.h>
+
+/**
+ * atomic_add_return - add integer to atomic variable
+ * @i: integer value to add
+ * @v: pointer of type atomic_t
+ *
+ * Atomically adds @i to @v and returns the result
+ * Note that the guaranteed useful range of an atomic_t is only 24 bits.
+ */
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+        unsigned long flags;
+        int temp;
+
+        local_irq_save(flags);
+        temp = v->counter;
+        temp += i;
+        v->counter = temp;
+        local_irq_restore(flags);
+
+        return temp;
+}
+
+/**
+ * atomic_sub_return - subtract integer from atomic variable
+ * @i: integer value to subtract
+ * @v: pointer of type atomic_t
+ *
+ * Atomically subtracts @i from @v and returns the result
+ * Note that the guaranteed useful range of an atomic_t is only 24 bits.
+ */
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+        unsigned long flags;
+        int temp;
+
+        local_irq_save(flags);
+        temp = v->counter;
+        temp -= i;
+        v->counter = temp;
+        local_irq_restore(flags);
+
+        return temp;
+}
+
+static inline int atomic_add_negative(int i, atomic_t *v)
+{
+        return atomic_add_return(i, v) < 0;
+}
+
+static inline void atomic_add(int i, atomic_t *v)
+{
+        atomic_add_return(i, v);
+}
+
+static inline void atomic_sub(int i, atomic_t *v)
+{
+        atomic_sub_return(i, v);
+}
+
+static inline void atomic_inc(atomic_t *v)
+{
+        atomic_add_return(1, v);
+}
+
+static inline void atomic_dec(atomic_t *v)
+{
+        atomic_sub_return(1, v);
+}
+
+#define atomic_dec_return(v)            atomic_sub_return(1, (v))
+#define atomic_inc_return(v)            atomic_add_return(1, (v))
+
+#define atomic_sub_and_test(i, v)       (atomic_sub_return((i), (v)) == 0)
+#define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
+#define atomic_inc_and_test(v)          (atomic_add_return(1, (v)) == 0)
+
+#define atomic_add_unless(v, a, u)                              \
+({                                                              \
+        int c, old;                                             \
+        c = atomic_read(v);                                     \
+        while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
+                c = old;                                        \
+        c != (u);                                               \
+})
+
+#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+
+static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+{
+        unsigned long flags;
+
+        mask = ~mask;
+        local_irq_save(flags);
+        *addr &= mask;
+        local_irq_restore(flags);
+}
+
+#define atomic_xchg(ptr, v)             (xchg(&(ptr)->counter, (v)))
+#define atomic_cmpxchg(v, old, new)     (cmpxchg(&((v)->counter), (old), (new)))
+
+#define cmpxchg_local(ptr, o, n)                                               \
+        ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
+                        (unsigned long)(n), sizeof(*(ptr))))
+
+#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
+
+/* Assume that atomic operations are already serializing */
+#define smp_mb__before_atomic_dec()     barrier()
+#define smp_mb__after_atomic_dec()      barrier()
+#define smp_mb__before_atomic_inc()     barrier()
+#define smp_mb__after_atomic_inc()      barrier()
+
+#include <asm-generic/atomic-long.h>
+
+#endif /* __KERNEL__ */
+#endif /* __ASM_GENERIC_ATOMIC_H */