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 28 #define ATOMIC_INIT(i) { (i) } 29 #define atomic_set(v, i) ((v)->counter = (i)) 30 31 /** 32 * atomic_read - reads a word, atomically 33 * @v: pointer to atomic value 34 * 35 * Assumes all word reads on our architecture are atomic. 36 */ 37 #define atomic_read(v) ((v)->counter) 38 39 /** 40 * atomic_xchg - atomic 41 * @v: pointer to memory to change 42 * @new: new value (technically passed in a register -- see xchg) 43 */ 44 #define atomic_xchg(v, new) (xchg(&((v)->counter), (new))) 45 46 47 /** 48 * atomic_cmpxchg - atomic compare-and-exchange values 49 * @v: pointer to value to change 50 * @old: desired old value to match 51 * @new: new value to put in 52 * 53 * Parameters are then pointer, value-in-register, value-in-register, 54 * and the output is the old value. 55 * 56 * Apparently this is complicated for archs that don't support 57 * the memw_locked like we do (or it's broken or whatever). 58 * 59 * Kind of the lynchpin of the rest of the generically defined routines. 60 * Remember V2 had that bug with dotnew predicate set by memw_locked. 61 * 62 * "old" is "expected" old val, __oldval is actual old value 63 */ 64 static inline int atomic_cmpxchg(atomic_t *v, int old, int new) 65 { 66 int __oldval; 67 68 asm volatile( 69 "1: %0 = memw_locked(%1);\n" 70 " { P0 = cmp.eq(%0,%2);\n" 71 " if (!P0.new) jump:nt 2f; }\n" 72 " memw_locked(%1,P0) = %3;\n" 73 " if (!P0) jump 1b;\n" 74 "2:\n" 75 : "=&r" (__oldval) 76 : "r" (&v->counter), "r" (old), "r" (new) 77 : "memory", "p0" 78 ); 79 80 return __oldval; 81 } 82 83 static inline int atomic_add_return(int i, atomic_t *v) 84 { 85 int output; 86 87 __asm__ __volatile__ ( 88 "1: %0 = memw_locked(%1);\n" 89 " %0 = add(%0,%2);\n" 90 " memw_locked(%1,P3)=%0;\n" 91 " if !P3 jump 1b;\n" 92 : "=&r" (output) 93 : "r" (&v->counter), "r" (i) 94 : "memory", "p3" 95 ); 96 return output; 97 98 } 99 100 #define atomic_add(i, v) atomic_add_return(i, (v)) 101 102 static inline int atomic_sub_return(int i, atomic_t *v) 103 { 104 int output; 105 __asm__ __volatile__ ( 106 "1: %0 = memw_locked(%1);\n" 107 " %0 = sub(%0,%2);\n" 108 " memw_locked(%1,P3)=%0\n" 109 " if !P3 jump 1b;\n" 110 : "=&r" (output) 111 : "r" (&v->counter), "r" (i) 112 : "memory", "p3" 113 ); 114 return output; 115 } 116 117 #define atomic_sub(i, v) atomic_sub_return(i, (v)) 118 119 /** 120 * __atomic_add_unless - add unless the number is a given value 121 * @v: pointer to value 122 * @a: amount to add 123 * @u: unless value is equal to u 124 * 125 * Returns old value. 126 * 127 */ 128 129 static inline int __atomic_add_unless(atomic_t *v, int a, int u) 130 { 131 int __oldval; 132 register int tmp; 133 134 asm volatile( 135 "1: %0 = memw_locked(%2);" 136 " {" 137 " p3 = cmp.eq(%0, %4);" 138 " if (p3.new) jump:nt 2f;" 139 " %1 = add(%0, %3);" 140 " }" 141 " memw_locked(%2, p3) = %1;" 142 " {" 143 " if !p3 jump 1b;" 144 " }" 145 "2:" 146 : "=&r" (__oldval), "=&r" (tmp) 147 : "r" (v), "r" (a), "r" (u) 148 : "memory", "p3" 149 ); 150 return __oldval; 151 } 152 153 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) 154 155 #define atomic_inc(v) atomic_add(1, (v)) 156 #define atomic_dec(v) atomic_sub(1, (v)) 157 158 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0) 159 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0) 160 #define atomic_sub_and_test(i, v) (atomic_sub_return(i, (v)) == 0) 161 #define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0) 162 163 164 #define atomic_inc_return(v) (atomic_add_return(1, v)) 165 #define atomic_dec_return(v) (atomic_sub_return(1, v)) 166 167 #endif 168