arch/avr32/include/asm/atomic.h

   1 /*
   2  * Atomic operations that C can't guarantee us.  Useful for
   3  * resource counting etc.
   4  *
   5  * But use these as seldom as possible since they are slower than
   6  * regular operations.
   7  *
   8  * Copyright (C) 2004-2006 Atmel Corporation
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14 #ifndef __ASM_AVR32_ATOMIC_H
  15 #define __ASM_AVR32_ATOMIC_H
  16
  17 #include <linux/types.h>
  18 #include <asm/system.h>
  19
  20 #define ATOMIC_INIT(i)  { (i) }
  21
  22 #define atomic_read(v)          (*(volatile int *)&(v)->counter)
  23 #define atomic_set(v, i)        (((v)->counter) = i)
  24
  25 /*
  26  * atomic_sub_return - subtract the atomic variable
  27  * @i: integer value to subtract
  28  * @v: pointer of type atomic_t
  29  *
  30  * Atomically subtracts @i from @v. Returns the resulting value.
  31  */
  32 static inline int atomic_sub_return(int i, atomic_t *v)
  33 {
  34         int result;
  35
  36         asm volatile(
  37                 "/* atomic_sub_return */\n"
  38                 "1:     ssrf    5\n"
  39                 "       ld.w    %0, %2\n"
  40                 "       sub     %0, %3\n"
  41                 "       stcond  %1, %0\n"
  42                 "       brne    1b"
  43                 : "=&r"(result), "=o"(v->counter)
  44                 : "m"(v->counter), "rKs21"(i)
  45                 : "cc");
  46
  47         return result;
  48 }
  49
  50 /*
  51  * atomic_add_return - add integer to atomic variable
  52  * @i: integer value to add
  53  * @v: pointer of type atomic_t
  54  *
  55  * Atomically adds @i to @v. Returns the resulting value.
  56  */
  57 static inline int atomic_add_return(int i, atomic_t *v)
  58 {
  59         int result;
  60
  61         if (__builtin_constant_p(i) && (i >= -1048575) && (i <= 1048576))
  62                 result = atomic_sub_return(-i, v);
  63         else
  64                 asm volatile(
  65                         "/* atomic_add_return */\n"
  66                         "1:     ssrf    5\n"
  67                         "       ld.w    %0, %1\n"
  68                         "       add     %0, %3\n"
  69                         "       stcond  %2, %0\n"
  70                         "       brne    1b"
  71                         : "=&r"(result), "=o"(v->counter)
  72                         : "m"(v->counter), "r"(i)
  73                         : "cc", "memory");
  74
  75         return result;
  76 }
  77
  78 /*
  79  * atomic_sub_unless - sub unless the number is a given value
  80  * @v: pointer of type atomic_t
  81  * @a: the amount to add to v...
  82  * @u: ...unless v is equal to u.
  83  *
  84  * If the atomic value v is not equal to u, this function subtracts a
  85  * from v, and returns non zero. If v is equal to u then it returns
  86  * zero. This is done as an atomic operation.
  87 */
  88 static inline int atomic_sub_unless(atomic_t *v, int a, int u)
  89 {
  90         int tmp, result = 0;
  91
  92         asm volatile(
  93                 "/* atomic_sub_unless */\n"
  94                 "1:     ssrf    5\n"
  95                 "       ld.w    %0, %3\n"
  96                 "       cp.w    %0, %5\n"
  97                 "       breq    1f\n"
  98                 "       sub     %0, %4\n"
  99                 "       stcond  %2, %0\n"
 100                 "       brne    1b\n"
 101                 "       mov     %1, 1\n"
 102                 "1:"
 103                 : "=&r"(tmp), "=&r"(result), "=o"(v->counter)
 104                 : "m"(v->counter), "rKs21"(a), "rKs21"(u), "1"(result)
 105                 : "cc", "memory");
 106
 107         return result;
 108 }
 109
 110 /*
 111  * atomic_add_unless - add unless the number is a given value
 112  * @v: pointer of type atomic_t
 113  * @a: the amount to add to v...
 114  * @u: ...unless v is equal to u.
 115  *
 116  * If the atomic value v is not equal to u, this function adds a to v,
 117  * and returns non zero. If v is equal to u then it returns zero. This
 118  * is done as an atomic operation.
 119 */
 120 static inline int atomic_add_unless(atomic_t *v, int a, int u)
 121 {
 122         int tmp, result;
 123
 124         if (__builtin_constant_p(a) && (a >= -1048575) && (a <= 1048576))
 125                 result = atomic_sub_unless(v, -a, u);
 126         else {
 127                 result = 0;
 128                 asm volatile(
 129                         "/* atomic_add_unless */\n"
 130                         "1:     ssrf    5\n"
 131                         "       ld.w    %0, %3\n"
 132                         "       cp.w    %0, %5\n"
 133                         "       breq    1f\n"
 134                         "       add     %0, %4\n"
 135                         "       stcond  %2, %0\n"
 136                         "       brne    1b\n"
 137                         "       mov     %1, 1\n"
 138                         "1:"
 139                         : "=&r"(tmp), "=&r"(result), "=o"(v->counter)
 140                         : "m"(v->counter), "r"(a), "ir"(u), "1"(result)
 141                         : "cc", "memory");
 142         }
 143
 144         return result;
 145 }
 146
 147 /*
 148  * atomic_sub_if_positive - conditionally subtract integer from atomic variable
 149  * @i: integer value to subtract
 150  * @v: pointer of type atomic_t
 151  *
 152  * Atomically test @v and subtract @i if @v is greater or equal than @i.
 153  * The function returns the old value of @v minus @i.
 154  */
 155 static inline int atomic_sub_if_positive(int i, atomic_t *v)
 156 {
 157         int result;
 158
 159         asm volatile(
 160                 "/* atomic_sub_if_positive */\n"
 161                 "1:     ssrf    5\n"
 162                 "       ld.w    %0, %2\n"
 163                 "       sub     %0, %3\n"
 164                 "       brlt    1f\n"
 165                 "       stcond  %1, %0\n"
 166                 "       brne    1b\n"
 167                 "1:"
 168                 : "=&r"(result), "=o"(v->counter)
 169                 : "m"(v->counter), "ir"(i)
 170                 : "cc", "memory");
 171
 172         return result;
 173 }
 174
 175 #define atomic_xchg(v, new)     (xchg(&((v)->counter), new))
 176 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
 177
 178 #define atomic_sub(i, v)        (void)atomic_sub_return(i, v)
 179 #define atomic_add(i, v)        (void)atomic_add_return(i, v)
 180 #define atomic_dec(v)           atomic_sub(1, (v))
 181 #define atomic_inc(v)           atomic_add(1, (v))
 182
 183 #define atomic_dec_return(v)    atomic_sub_return(1, v)
 184 #define atomic_inc_return(v)    atomic_add_return(1, v)
 185
 186 #define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)
 187 #define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0)
 188 #define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0)
 189 #define atomic_add_negative(i, v) (atomic_add_return(i, v) < 0)
 190
 191 #define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
 192
 193 #define smp_mb__before_atomic_dec()     barrier()
 194 #define smp_mb__after_atomic_dec()      barrier()
 195 #define smp_mb__before_atomic_inc()     barrier()
 196 #define smp_mb__after_atomic_inc()      barrier()
 197
 198 #include <asm-generic/atomic-long.h>
 199
 200 #endif /*  __ASM_AVR32_ATOMIC_H */