1 /* 2 * include/asm-xtensa/atomic.h 3 * 4 * Atomic operations that C can't guarantee us. Useful for resource counting.. 5 * 6 * This file is subject to the terms and conditions of the GNU General Public 7 * License. See the file "COPYING" in the main directory of this archive 8 * for more details. 9 * 10 * Copyright (C) 2001 - 2008 Tensilica Inc. 11 */ 12 13 #ifndef _XTENSA_ATOMIC_H 14 #define _XTENSA_ATOMIC_H 15 16 #include <linux/stringify.h> 17 #include <linux/types.h> 18 #include <asm/processor.h> 19 #include <asm/cmpxchg.h> 20 #include <asm/barrier.h> 21 22 /* 23 * This Xtensa implementation assumes that the right mechanism 24 * for exclusion is for locking interrupts to level EXCM_LEVEL. 25 * 26 * Locking interrupts looks like this: 27 * 28 * rsil a15, TOPLEVEL 29 * <code> 30 * wsr a15, PS 31 * rsync 32 * 33 * Note that a15 is used here because the register allocation 34 * done by the compiler is not guaranteed and a window overflow 35 * may not occur between the rsil and wsr instructions. By using 36 * a15 in the rsil, the machine is guaranteed to be in a state 37 * where no register reference will cause an overflow. 38 */ 39 40 /** 41 * atomic_read - read atomic variable 42 * @v: pointer of type atomic_t 43 * 44 * Atomically reads the value of @v. 45 */ 46 #define arch_atomic_read(v) READ_ONCE((v)->counter) 47 48 /** 49 * atomic_set - set atomic variable 50 * @v: pointer of type atomic_t 51 * @i: required value 52 * 53 * Atomically sets the value of @v to @i. 54 */ 55 #define arch_atomic_set(v,i) WRITE_ONCE((v)->counter, (i)) 56 57 #if XCHAL_HAVE_EXCLUSIVE 58 #define ATOMIC_OP(op) \ 59 static inline void arch_atomic_##op(int i, atomic_t *v) \ 60 { \ 61 unsigned long tmp; \ 62 int result; \ 63 \ 64 __asm__ __volatile__( \ 65 "1: l32ex %[tmp], %[addr]\n" \ 66 " " #op " %[result], %[tmp], %[i]\n" \ 67 " s32ex %[result], %[addr]\n" \ 68 " getex %[result]\n" \ 69 " beqz %[result], 1b\n" \ 70 : [result] "=&a" (result), [tmp] "=&a" (tmp) \ 71 : [i] "a" (i), [addr] "a" (v) \ 72 : "memory" \ 73 ); \ 74 } \ 75 76 #define ATOMIC_OP_RETURN(op) \ 77 static inline int arch_atomic_##op##_return(int i, atomic_t *v) \ 78 { \ 79 unsigned long tmp; \ 80 int result; \ 81 \ 82 __asm__ __volatile__( \ 83 "1: l32ex %[tmp], %[addr]\n" \ 84 " " #op " %[result], %[tmp], %[i]\n" \ 85 " s32ex %[result], %[addr]\n" \ 86 " getex %[result]\n" \ 87 " beqz %[result], 1b\n" \ 88 " " #op " %[result], %[tmp], %[i]\n" \ 89 : [result] "=&a" (result), [tmp] "=&a" (tmp) \ 90 : [i] "a" (i), [addr] "a" (v) \ 91 : "memory" \ 92 ); \ 93 \ 94 return result; \ 95 } 96 97 #define ATOMIC_FETCH_OP(op) \ 98 static inline int arch_atomic_fetch_##op(int i, atomic_t *v) \ 99 { \ 100 unsigned long tmp; \ 101 int result; \ 102 \ 103 __asm__ __volatile__( \ 104 "1: l32ex %[tmp], %[addr]\n" \ 105 " " #op " %[result], %[tmp], %[i]\n" \ 106 " s32ex %[result], %[addr]\n" \ 107 " getex %[result]\n" \ 108 " beqz %[result], 1b\n" \ 109 : [result] "=&a" (result), [tmp] "=&a" (tmp) \ 110 : [i] "a" (i), [addr] "a" (v) \ 111 : "memory" \ 112 ); \ 113 \ 114 return tmp; \ 115 } 116 117 #elif XCHAL_HAVE_S32C1I 118 #define ATOMIC_OP(op) \ 119 static inline void arch_atomic_##op(int i, atomic_t * v) \ 120 { \ 121 unsigned long tmp; \ 122 int result; \ 123 \ 124 __asm__ __volatile__( \ 125 "1: l32i %[tmp], %[mem]\n" \ 126 " wsr %[tmp], scompare1\n" \ 127 " " #op " %[result], %[tmp], %[i]\n" \ 128 " s32c1i %[result], %[mem]\n" \ 129 " bne %[result], %[tmp], 1b\n" \ 130 : [result] "=&a" (result), [tmp] "=&a" (tmp), \ 131 [mem] "+m" (*v) \ 132 : [i] "a" (i) \ 133 : "memory" \ 134 ); \ 135 } \ 136 137 #define ATOMIC_OP_RETURN(op) \ 138 static inline int arch_atomic_##op##_return(int i, atomic_t * v) \ 139 { \ 140 unsigned long tmp; \ 141 int result; \ 142 \ 143 __asm__ __volatile__( \ 144 "1: l32i %[tmp], %[mem]\n" \ 145 " wsr %[tmp], scompare1\n" \ 146 " " #op " %[result], %[tmp], %[i]\n" \ 147 " s32c1i %[result], %[mem]\n" \ 148 " bne %[result], %[tmp], 1b\n" \ 149 " " #op " %[result], %[result], %[i]\n" \ 150 : [result] "=&a" (result), [tmp] "=&a" (tmp), \ 151 [mem] "+m" (*v) \ 152 : [i] "a" (i) \ 153 : "memory" \ 154 ); \ 155 \ 156 return result; \ 157 } 158 159 #define ATOMIC_FETCH_OP(op) \ 160 static inline int arch_atomic_fetch_##op(int i, atomic_t * v) \ 161 { \ 162 unsigned long tmp; \ 163 int result; \ 164 \ 165 __asm__ __volatile__( \ 166 "1: l32i %[tmp], %[mem]\n" \ 167 " wsr %[tmp], scompare1\n" \ 168 " " #op " %[result], %[tmp], %[i]\n" \ 169 " s32c1i %[result], %[mem]\n" \ 170 " bne %[result], %[tmp], 1b\n" \ 171 : [result] "=&a" (result), [tmp] "=&a" (tmp), \ 172 [mem] "+m" (*v) \ 173 : [i] "a" (i) \ 174 : "memory" \ 175 ); \ 176 \ 177 return result; \ 178 } 179 180 #else /* XCHAL_HAVE_S32C1I */ 181 182 #define ATOMIC_OP(op) \ 183 static inline void arch_atomic_##op(int i, atomic_t * v) \ 184 { \ 185 unsigned int vval; \ 186 \ 187 __asm__ __volatile__( \ 188 " rsil a15, "__stringify(TOPLEVEL)"\n" \ 189 " l32i %[result], %[mem]\n" \ 190 " " #op " %[result], %[result], %[i]\n" \ 191 " s32i %[result], %[mem]\n" \ 192 " wsr a15, ps\n" \ 193 " rsync\n" \ 194 : [result] "=&a" (vval), [mem] "+m" (*v) \ 195 : [i] "a" (i) \ 196 : "a15", "memory" \ 197 ); \ 198 } \ 199 200 #define ATOMIC_OP_RETURN(op) \ 201 static inline int arch_atomic_##op##_return(int i, atomic_t * v) \ 202 { \ 203 unsigned int vval; \ 204 \ 205 __asm__ __volatile__( \ 206 " rsil a15,"__stringify(TOPLEVEL)"\n" \ 207 " l32i %[result], %[mem]\n" \ 208 " " #op " %[result], %[result], %[i]\n" \ 209 " s32i %[result], %[mem]\n" \ 210 " wsr a15, ps\n" \ 211 " rsync\n" \ 212 : [result] "=&a" (vval), [mem] "+m" (*v) \ 213 : [i] "a" (i) \ 214 : "a15", "memory" \ 215 ); \ 216 \ 217 return vval; \ 218 } 219 220 #define ATOMIC_FETCH_OP(op) \ 221 static inline int arch_atomic_fetch_##op(int i, atomic_t * v) \ 222 { \ 223 unsigned int tmp, vval; \ 224 \ 225 __asm__ __volatile__( \ 226 " rsil a15,"__stringify(TOPLEVEL)"\n" \ 227 " l32i %[result], %[mem]\n" \ 228 " " #op " %[tmp], %[result], %[i]\n" \ 229 " s32i %[tmp], %[mem]\n" \ 230 " wsr a15, ps\n" \ 231 " rsync\n" \ 232 : [result] "=&a" (vval), [tmp] "=&a" (tmp), \ 233 [mem] "+m" (*v) \ 234 : [i] "a" (i) \ 235 : "a15", "memory" \ 236 ); \ 237 \ 238 return vval; \ 239 } 240 241 #endif /* XCHAL_HAVE_S32C1I */ 242 243 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) ATOMIC_OP_RETURN(op) 244 245 ATOMIC_OPS(add) 246 ATOMIC_OPS(sub) 247 248 #undef ATOMIC_OPS 249 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) 250 251 ATOMIC_OPS(and) 252 ATOMIC_OPS(or) 253 ATOMIC_OPS(xor) 254 255 #undef ATOMIC_OPS 256 #undef ATOMIC_FETCH_OP 257 #undef ATOMIC_OP_RETURN 258 #undef ATOMIC_OP 259 260 #define arch_atomic_cmpxchg(v, o, n) ((int)arch_cmpxchg(&((v)->counter), (o), (n))) 261 #define arch_atomic_xchg(v, new) (arch_xchg(&((v)->counter), new)) 262 263 #endif /* _XTENSA_ATOMIC_H */ 264