1 files changed, 165 insertions, 0 deletions

diff --git a/include/asm-arm/atomic.h b/include/asm-arm/atomic.h
new file mode 100644
index 000000000000..2885972b0855
--- /dev/null
+++ b/include/asm-arm/atomic.h
@@ -0,0 +1,165 @@
+/*
+ *  linux/include/asm-arm/atomic.h
+ *
+ *  Copyright (C) 1996 Russell King.
+ *  Copyright (C) 2002 Deep Blue Solutions Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __ASM_ARM_ATOMIC_H
+#define __ASM_ARM_ATOMIC_H
+
+#include <linux/config.h>
+
+typedef struct { volatile int counter; } atomic_t;
+
+#define ATOMIC_INIT(i)  { (i) }
+
+#ifdef __KERNEL__
+
+#define atomic_read(v)  ((v)->counter)
+
+#if __LINUX_ARM_ARCH__ >= 6
+
+/*
+ * ARMv6 UP and SMP safe atomic ops.  We use load exclusive and
+ * store exclusive to ensure that these are atomic.  We may loop
+ * to ensure that the update happens.  Writing to 'v->counter'
+ * without using the following operations WILL break the atomic
+ * nature of these ops.
+ */
+static inline void atomic_set(atomic_t *v, int i)
+{
+        unsigned long tmp;
+
+        __asm__ __volatile__("@ atomic_set\n"
+"1:     ldrex   %0, [%1]\n"
+"       strex   %0, %2, [%1]\n"
+"       teq     %0, #0\n"
+"       bne     1b"
+        : "=&r" (tmp)
+        : "r" (&v->counter), "r" (i)
+        : "cc");
+}
+
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+        unsigned long tmp;
+        int result;
+
+        __asm__ __volatile__("@ atomic_add_return\n"
+"1:     ldrex   %0, [%2]\n"
+"       add     %0, %0, %3\n"
+"       strex   %1, %0, [%2]\n"
+"       teq     %1, #0\n"
+"       bne     1b"
+        : "=&r" (result), "=&r" (tmp)
+        : "r" (&v->counter), "Ir" (i)
+        : "cc");
+
+        return result;
+}
+
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+        unsigned long tmp;
+        int result;
+
+        __asm__ __volatile__("@ atomic_sub_return\n"
+"1:     ldrex   %0, [%2]\n"
+"       sub     %0, %0, %3\n"
+"       strex   %1, %0, [%2]\n"
+"       teq     %1, #0\n"
+"       bne     1b"
+        : "=&r" (result), "=&r" (tmp)
+        : "r" (&v->counter), "Ir" (i)
+        : "cc");
+
+        return result;
+}
+
+static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+{
+        unsigned long tmp, tmp2;
+
+        __asm__ __volatile__("@ atomic_clear_mask\n"
+"1:     ldrex   %0, %2\n"
+"       bic     %0, %0, %3\n"
+"       strex   %1, %0, %2\n"
+"       teq     %1, #0\n"
+"       bne     1b"
+        : "=&r" (tmp), "=&r" (tmp2)
+        : "r" (addr), "Ir" (mask)
+        : "cc");
+}
+
+#else /* ARM_ARCH_6 */
+
+#include <asm/system.h>
+
+#ifdef CONFIG_SMP
+#error SMP not supported on pre-ARMv6 CPUs
+#endif
+
+#define atomic_set(v,i) (((v)->counter) = (i))
+
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+        unsigned long flags;
+        int val;
+
+        local_irq_save(flags);
+        val = v->counter;
+        v->counter = val += i;
+        local_irq_restore(flags);
+
+        return val;
+}
+
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+        unsigned long flags;
+        int val;
+
+        local_irq_save(flags);
+        val = v->counter;
+        v->counter = val -= i;
+        local_irq_restore(flags);
+
+        return val;
+}
+
+static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+{
+        unsigned long flags;
+
+        local_irq_save(flags);
+        *addr &= ~mask;
+        local_irq_restore(flags);
+}
+
+#endif /* __LINUX_ARM_ARCH__ */
+
+#define atomic_add(i, v)        (void) atomic_add_return(i, v)
+#define atomic_inc(v)           (void) atomic_add_return(1, v)
+#define atomic_sub(i, v)        (void) atomic_sub_return(i, v)
+#define atomic_dec(v)           (void) atomic_sub_return(1, v)
+
+#define atomic_inc_and_test(v)  (atomic_add_return(1, v) == 0)
+#define atomic_dec_and_test(v)  (atomic_sub_return(1, v) == 0)
+#define atomic_inc_return(v)    (atomic_add_return(1, v))
+#define atomic_dec_return(v)    (atomic_sub_return(1, v))
+#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)
+
+#define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0)
+
+/* Atomic operations are already serializing on ARM */
+#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()
+
+#endif
+#endif