/* * 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 */