arch/hexagon/include/asm/atomic.h

   1 /*
   2  * Atomic operations for the Hexagon architecture
   3  *
   4  * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 and
   9  * only version 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19  * 02110-1301, USA.
  20  */
  21
  22 #ifndef _ASM_ATOMIC_H
  23 #define _ASM_ATOMIC_H
  24
  25 #include <linux/types.h>
  26 #include <asm/cmpxchg.h>
  27 #include <asm/barrier.h>
  28
  29 #define ATOMIC_INIT(i)          { (i) }
  30
  31 /*  Normal writes in our arch don't clear lock reservations  */
  32
  33 static inline void atomic_set(atomic_t *v, int new)
  34 {
  35         asm volatile(
  36                 "1:     r6 = memw_locked(%0);\n"
  37                 "       memw_locked(%0,p0) = %1;\n"
  38                 "       if (!P0) jump 1b;\n"
  39                 :
  40                 : "r" (&v->counter), "r" (new)
  41                 : "memory", "p0", "r6"
  42         );
  43 }
  44
  45 #define atomic_set_release(v, i)        atomic_set((v), (i))
  46
  47 /**
  48  * atomic_read - reads a word, atomically
  49  * @v: pointer to atomic value
  50  *
  51  * Assumes all word reads on our architecture are atomic.
  52  */
  53 #define atomic_read(v)          READ_ONCE((v)->counter)
  54
  55 /**
  56  * atomic_xchg - atomic
  57  * @v: pointer to memory to change
  58  * @new: new value (technically passed in a register -- see xchg)
  59  */
  60 #define atomic_xchg(v, new)     (xchg(&((v)->counter), (new)))
  61
  62
  63 /**
  64  * atomic_cmpxchg - atomic compare-and-exchange values
  65  * @v: pointer to value to change
  66  * @old:  desired old value to match
  67  * @new:  new value to put in
  68  *
  69  * Parameters are then pointer, value-in-register, value-in-register,
  70  * and the output is the old value.
  71  *
  72  * Apparently this is complicated for archs that don't support
  73  * the memw_locked like we do (or it's broken or whatever).
  74  *
  75  * Kind of the lynchpin of the rest of the generically defined routines.
  76  * Remember V2 had that bug with dotnew predicate set by memw_locked.
  77  *
  78  * "old" is "expected" old val, __oldval is actual old value
  79  */
  80 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
  81 {
  82         int __oldval;
  83
  84         asm volatile(
  85                 "1:     %0 = memw_locked(%1);\n"
  86                 "       { P0 = cmp.eq(%0,%2);\n"
  87                 "         if (!P0.new) jump:nt 2f; }\n"
  88                 "       memw_locked(%1,P0) = %3;\n"
  89                 "       if (!P0) jump 1b;\n"
  90                 "2:\n"
  91                 : "=&r" (__oldval)
  92                 : "r" (&v->counter), "r" (old), "r" (new)
  93                 : "memory", "p0"
  94         );
  95
  96         return __oldval;
  97 }
  98
  99 #define ATOMIC_OP(op)                                                   \
 100 static inline void atomic_##op(int i, atomic_t *v)                      \
 101 {                                                                       \
 102         int output;                                                     \
 103                                                                         \
 104         __asm__ __volatile__ (                                          \
 105                 "1:     %0 = memw_locked(%1);\n"                        \
 106                 "       %0 = "#op "(%0,%2);\n"                          \
 107                 "       memw_locked(%1,P3)=%0;\n"                       \
 108                 "       if !P3 jump 1b;\n"                              \
 109                 : "=&r" (output)                                        \
 110                 : "r" (&v->counter), "r" (i)                            \
 111                 : "memory", "p3"                                        \
 112         );                                                              \
 113 }                                                                       \
 114
 115 #define ATOMIC_OP_RETURN(op)                                            \
 116 static inline int atomic_##op##_return(int i, atomic_t *v)              \
 117 {                                                                       \
 118         int output;                                                     \
 119                                                                         \
 120         __asm__ __volatile__ (                                          \
 121                 "1:     %0 = memw_locked(%1);\n"                        \
 122                 "       %0 = "#op "(%0,%2);\n"                          \
 123                 "       memw_locked(%1,P3)=%0;\n"                       \
 124                 "       if !P3 jump 1b;\n"                              \
 125                 : "=&r" (output)                                        \
 126                 : "r" (&v->counter), "r" (i)                            \
 127                 : "memory", "p3"                                        \
 128         );                                                              \
 129         return output;                                                  \
 130 }
 131
 132 #define ATOMIC_FETCH_OP(op)                                             \
 133 static inline int atomic_fetch_##op(int i, atomic_t *v)                 \
 134 {                                                                       \
 135         int output, val;                                                \
 136                                                                         \
 137         __asm__ __volatile__ (                                          \
 138                 "1:     %0 = memw_locked(%2);\n"                        \
 139                 "       %1 = "#op "(%0,%3);\n"                          \
 140                 "       memw_locked(%2,P3)=%1;\n"                       \
 141                 "       if !P3 jump 1b;\n"                              \
 142                 : "=&r" (output), "=&r" (val)                           \
 143                 : "r" (&v->counter), "r" (i)                            \
 144                 : "memory", "p3"                                        \
 145         );                                                              \
 146         return output;                                                  \
 147 }
 148
 149 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
 150
 151 ATOMIC_OPS(add)
 152 ATOMIC_OPS(sub)
 153
 154 #undef ATOMIC_OPS
 155 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
 156
 157 ATOMIC_OPS(and)
 158 ATOMIC_OPS(or)
 159 ATOMIC_OPS(xor)
 160
 161 #undef ATOMIC_OPS
 162 #undef ATOMIC_FETCH_OP
 163 #undef ATOMIC_OP_RETURN
 164 #undef ATOMIC_OP
 165
 166 /**
 167  * __atomic_add_unless - add unless the number is a given value
 168  * @v: pointer to value
 169  * @a: amount to add
 170  * @u: unless value is equal to u
 171  *
 172  * Returns old value.
 173  *
 174  */
 175
 176 static inline int __atomic_add_unless(atomic_t *v, int a, int u)
 177 {
 178         int __oldval;
 179         register int tmp;
 180
 181         asm volatile(
 182                 "1:     %0 = memw_locked(%2);"
 183                 "       {"
 184                 "               p3 = cmp.eq(%0, %4);"
 185                 "               if (p3.new) jump:nt 2f;"
 186                 "               %1 = add(%0, %3);"
 187                 "       }"
 188                 "       memw_locked(%2, p3) = %1;"
 189                 "       {"
 190                 "               if !p3 jump 1b;"
 191                 "       }"
 192                 "2:"
 193                 : "=&r" (__oldval), "=&r" (tmp)
 194                 : "r" (v), "r" (a), "r" (u)
 195                 : "memory", "p3"
 196         );
 197         return __oldval;
 198 }
 199
 200 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 201
 202 #define atomic_inc(v) atomic_add(1, (v))
 203 #define atomic_dec(v) atomic_sub(1, (v))
 204
 205 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
 206 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
 207 #define atomic_sub_and_test(i, v) (atomic_sub_return(i, (v)) == 0)
 208 #define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0)
 209
 210 #define atomic_inc_return(v) (atomic_add_return(1, v))
 211 #define atomic_dec_return(v) (atomic_sub_return(1, v))
 212
 213 #endif