--- /dev/null
+/*
+ * Atomic operations that C can't guarantee us. Useful for
+ * resource counting etc.
+ *
+ * But use these as seldom as possible since they are slower than
+ * regular operations.
+ *
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * 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_AVR32_ATOMIC_H
+#define __ASM_AVR32_ATOMIC_H
+
+#include <asm/system.h>
+
+typedef struct { volatile int counter; } atomic_t;
+#define ATOMIC_INIT(i) { (i) }
+
+#define atomic_read(v) ((v)->counter)
+#define atomic_set(v, i) (((v)->counter) = i)
+
+/*
+ * atomic_sub_return - subtract the atomic variable
+ * @i: integer value to subtract
+ * @v: pointer of type atomic_t
+ *
+ * Atomically subtracts @i from @v. Returns the resulting value.
+ */
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+ int result;
+
+ asm volatile(
+ "/* atomic_sub_return */\n"
+ "1: ssrf 5\n"
+ " ld.w %0, %2\n"
+ " sub %0, %3\n"
+ " stcond %1, %0\n"
+ " brne 1b"
+ : "=&r"(result), "=o"(v->counter)
+ : "m"(v->counter), "rKs21"(i)
+ : "cc");
+
+ return result;
+}
+
+/*
+ * atomic_add_return - add integer to atomic variable
+ * @i: integer value to add
+ * @v: pointer of type atomic_t
+ *
+ * Atomically adds @i to @v. Returns the resulting value.
+ */
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+ int result;
+
+ if (__builtin_constant_p(i) && (i >= -1048575) && (i <= 1048576))
+ result = atomic_sub_return(-i, v);
+ else
+ asm volatile(
+ "/* atomic_add_return */\n"
+ "1: ssrf 5\n"
+ " ld.w %0, %1\n"
+ " add %0, %3\n"
+ " stcond %2, %0\n"
+ " brne 1b"
+ : "=&r"(result), "=o"(v->counter)
+ : "m"(v->counter), "r"(i)
+ : "cc", "memory");
+
+ return result;
+}
+
+/*
+ * atomic_sub_unless - sub unless the number is a given value
+ * @v: pointer of type atomic_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * If the atomic value v is not equal to u, this function subtracts a
+ * from v, and returns non zero. If v is equal to u then it returns
+ * zero. This is done as an atomic operation.
+*/
+static inline int atomic_sub_unless(atomic_t *v, int a, int u)
+{
+ int tmp, result = 0;
+
+ asm volatile(
+ "/* atomic_sub_unless */\n"
+ "1: ssrf 5\n"
+ " ld.w %0, %3\n"
+ " cp.w %0, %5\n"
+ " breq 1f\n"
+ " sub %0, %4\n"
+ " stcond %2, %0\n"
+ " brne 1b\n"
+ " mov %1, 1\n"
+ "1:"
+ : "=&r"(tmp), "=&r"(result), "=o"(v->counter)
+ : "m"(v->counter), "rKs21"(a), "rKs21"(u)
+ : "cc", "memory");
+
+ return result;
+}
+
+/*
+ * atomic_add_unless - add unless the number is a given value
+ * @v: pointer of type atomic_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * If the atomic value v is not equal to u, this function adds a to v,
+ * and returns non zero. If v is equal to u then it returns zero. This
+ * is done as an atomic operation.
+*/
+static inline int atomic_add_unless(atomic_t *v, int a, int u)
+{
+ int tmp, result;
+
+ if (__builtin_constant_p(a) && (a >= -1048575) && (a <= 1048576))
+ result = atomic_sub_unless(v, -a, u);
+ else {
+ result = 0;
+ asm volatile(
+ "/* atomic_add_unless */\n"
+ "1: ssrf 5\n"
+ " ld.w %0, %3\n"
+ " cp.w %0, %5\n"
+ " breq 1f\n"
+ " add %0, %4\n"
+ " stcond %2, %0\n"
+ " brne 1b\n"
+ " mov %1, 1\n"
+ "1:"
+ : "=&r"(tmp), "=&r"(result), "=o"(v->counter)
+ : "m"(v->counter), "r"(a), "ir"(u)
+ : "cc", "memory");
+ }
+
+ return result;
+}
+
+/*
+ * atomic_sub_if_positive - conditionally subtract integer from atomic variable
+ * @i: integer value to subtract
+ * @v: pointer of type atomic_t
+ *
+ * Atomically test @v and subtract @i if @v is greater or equal than @i.
+ * The function returns the old value of @v minus @i.
+ */
+static inline int atomic_sub_if_positive(int i, atomic_t *v)
+{
+ int result;
+
+ asm volatile(
+ "/* atomic_sub_if_positive */\n"
+ "1: ssrf 5\n"
+ " ld.w %0, %2\n"
+ " sub %0, %3\n"
+ " brlt 1f\n"
+ " stcond %1, %0\n"
+ " brne 1b\n"
+ "1:"
+ : "=&r"(result), "=o"(v->counter)
+ : "m"(v->counter), "ir"(i)
+ : "cc", "memory");
+
+ return result;
+}
+
+#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
+#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
+
+#define atomic_sub(i, v) (void)atomic_sub_return(i, v)
+#define atomic_add(i, v) (void)atomic_add_return(i, v)
+#define atomic_dec(v) atomic_sub(1, (v))
+#define atomic_inc(v) atomic_add(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_inc_and_test(v) (atomic_add_return(1, v) == 0)
+#define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0)
+#define atomic_add_negative(i, v) (atomic_add_return(i, v) < 0)
+
+#define atomic_inc_not_zero(v) atomic_add_unless(v, 1, 0)
+#define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
+
+#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.h>
+
+#endif /* __ASM_AVR32_ATOMIC_H */
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