1 /* 2 * Atomic operations for the Hexagon architecture 3 * 4 * Copyright (c) 2010-2011, Code Aurora Forum. 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 27 #define ATOMIC_INIT(i) { (i) } 28 #define atomic_set(v, i) ((v)->counter = (i)) 29 30 /** 31 * atomic_read - reads a word, atomically 32 * @v: pointer to atomic value 33 * 34 * Assumes all word reads on our architecture are atomic. 35 */ 36 #define atomic_read(v) ((v)->counter) 37 38 /** 39 * atomic_xchg - atomic 40 * @v: pointer to memory to change 41 * @new: new value (technically passed in a register -- see xchg) 42 */ 43 #define atomic_xchg(v, new) (xchg(&((v)->counter), (new))) 44 45 46 /** 47 * atomic_cmpxchg - atomic compare-and-exchange values 48 * @v: pointer to value to change 49 * @old: desired old value to match 50 * @new: new value to put in 51 * 52 * Parameters are then pointer, value-in-register, value-in-register, 53 * and the output is the old value. 54 * 55 * Apparently this is complicated for archs that don't support 56 * the memw_locked like we do (or it's broken or whatever). 57 * 58 * Kind of the lynchpin of the rest of the generically defined routines. 59 * Remember V2 had that bug with dotnew predicate set by memw_locked. 60 * 61 * "old" is "expected" old val, __oldval is actual old value 62 */ 63 static inline int atomic_cmpxchg(atomic_t *v, int old, int new) 64 { 65 int __oldval; 66 67 asm volatile( 68 "1: %0 = memw_locked(%1);\n" 69 " { P0 = cmp.eq(%0,%2);\n" 70 " if (!P0.new) jump:nt 2f; }\n" 71 " memw_locked(%1,P0) = %3;\n" 72 " if (!P0) jump 1b;\n" 73 "2:\n" 74 : "=&r" (__oldval) 75 : "r" (&v->counter), "r" (old), "r" (new) 76 : "memory", "p0" 77 ); 78 79 return __oldval; 80 } 81 82 static inline int atomic_add_return(int i, atomic_t *v) 83 { 84 int output; 85 86 __asm__ __volatile__ ( 87 "1: %0 = memw_locked(%1);\n" 88 " %0 = add(%0,%2);\n" 89 " memw_locked(%1,P3)=%0;\n" 90 " if !P3 jump 1b;\n" 91 : "=&r" (output) 92 : "r" (&v->counter), "r" (i) 93 : "memory", "p3" 94 ); 95 return output; 96 97 } 98 99 #define atomic_add(i, v) atomic_add_return(i, (v)) 100 101 static inline int atomic_sub_return(int i, atomic_t *v) 102 { 103 int output; 104 __asm__ __volatile__ ( 105 "1: %0 = memw_locked(%1);\n" 106 " %0 = sub(%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 return output; 114 } 115 116 #define atomic_sub(i, v) atomic_sub_return(i, (v)) 117 118 /** 119 * atomic_add_unless - add unless the number is a given value 120 * @v: pointer to value 121 * @a: amount to add 122 * @u: unless value is equal to u 123 * 124 * Returns 1 if the add happened, 0 if it didn't. 125 */ 126 static inline int __atomic_add_unless(atomic_t *v, int a, int u) 127 { 128 int output, __oldval; 129 asm volatile( 130 "1: %0 = memw_locked(%2);" 131 " {" 132 " p3 = cmp.eq(%0, %4);" 133 " if (p3.new) jump:nt 2f;" 134 " %0 = add(%0, %3);" 135 " %1 = #0;" 136 " }" 137 " memw_locked(%2, p3) = %0;" 138 " {" 139 " if !p3 jump 1b;" 140 " %1 = #1;" 141 " }" 142 "2:" 143 : "=&r" (__oldval), "=&r" (output) 144 : "r" (v), "r" (a), "r" (u) 145 : "memory", "p3" 146 ); 147 return output; 148 } 149 150 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) 151 152 #define atomic_inc(v) atomic_add(1, (v)) 153 #define atomic_dec(v) atomic_sub(1, (v)) 154 155 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0) 156 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0) 157 #define atomic_sub_and_test(i, v) (atomic_sub_return(i, (v)) == 0) 158 #define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0) 159 160 161 #define atomic_inc_return(v) (atomic_add_return(1, v)) 162 #define atomic_dec_return(v) (atomic_sub_return(1, v)) 163 164 #endif 165