diff options
Diffstat (limited to 'arch/avr32/include/asm/atomic.h')
| -rw-r--r-- | arch/avr32/include/asm/atomic.h | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/arch/avr32/include/asm/atomic.h b/arch/avr32/include/asm/atomic.h new file mode 100644 index 00000000000..7ef3862a73d --- /dev/null +++ b/arch/avr32/include/asm/atomic.h @@ -0,0 +1,201 @@ +/* + * 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), "1"(result) + : "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), "1"(result) + : "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) (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 */ |