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 /** 46 * atomic_read - reads a word, atomically 47 * @v: pointer to atomic value 48 * 49 * Assumes all word reads on our architecture are atomic. 50 */ 51 #define atomic_read(v) ((v)->counter) 52 53 /** 54 * atomic_xchg - atomic 55 * @v: pointer to memory to change 56 * @new: new value (technically passed in a register -- see xchg) 57 */ 58 #define atomic_xchg(v, new) (xchg(&((v)->counter), (new))) 59 60 61 /** 62 * atomic_cmpxchg - atomic compare-and-exchange values 63 * @v: pointer to value to change 64 * @old: desired old value to match 65 * @new: new value to put in 66 * 67 * Parameters are then pointer, value-in-register, value-in-register, 68 * and the output is the old value. 69 * 70 * Apparently this is complicated for archs that don't support 71 * the memw_locked like we do (or it's broken or whatever). 72 * 73 * Kind of the lynchpin of the rest of the generically defined routines. 74 * Remember V2 had that bug with dotnew predicate set by memw_locked. 75 * 76 * "old" is "expected" old val, __oldval is actual old value 77 */ 78 static inline int atomic_cmpxchg(atomic_t *v, int old, int new) 79 { 80 int __oldval; 81 82 asm volatile( 83 "1: %0 = memw_locked(%1);\n" 84 " { P0 = cmp.eq(%0,%2);\n" 85 " if (!P0.new) jump:nt 2f; }\n" 86 " memw_locked(%1,P0) = %3;\n" 87 " if (!P0) jump 1b;\n" 88 "2:\n" 89 : "=&r" (__oldval) 90 : "r" (&v->counter), "r" (old), "r" (new) 91 : "memory", "p0" 92 ); 93 94 return __oldval; 95 } 96 97 static inline int atomic_add_return(int i, atomic_t *v) 98 { 99 int output; 100 101 __asm__ __volatile__ ( 102 "1: %0 = memw_locked(%1);\n" 103 " %0 = add(%0,%2);\n" 104 " memw_locked(%1,P3)=%0;\n" 105 " if !P3 jump 1b;\n" 106 : "=&r" (output) 107 : "r" (&v->counter), "r" (i) 108 : "memory", "p3" 109 ); 110 return output; 111 112 } 113 114 #define atomic_add(i, v) atomic_add_return(i, (v)) 115 116 static inline int atomic_sub_return(int i, atomic_t *v) 117 { 118 int output; 119 __asm__ __volatile__ ( 120 "1: %0 = memw_locked(%1);\n" 121 " %0 = sub(%0,%2);\n" 122 " memw_locked(%1,P3)=%0\n" 123 " if !P3 jump 1b;\n" 124 : "=&r" (output) 125 : "r" (&v->counter), "r" (i) 126 : "memory", "p3" 127 ); 128 return output; 129 } 130 131 #define atomic_sub(i, v) atomic_sub_return(i, (v)) 132 133 /** 134 * __atomic_add_unless - add unless the number is a given value 135 * @v: pointer to value 136 * @a: amount to add 137 * @u: unless value is equal to u 138 * 139 * Returns old value. 140 * 141 */ 142 143 static inline int __atomic_add_unless(atomic_t *v, int a, int u) 144 { 145 int __oldval; 146 register int tmp; 147 148 asm volatile( 149 "1: %0 = memw_locked(%2);" 150 " {" 151 " p3 = cmp.eq(%0, %4);" 152 " if (p3.new) jump:nt 2f;" 153 " %1 = add(%0, %3);" 154 " }" 155 " memw_locked(%2, p3) = %1;" 156 " {" 157 " if !p3 jump 1b;" 158 " }" 159 "2:" 160 : "=&r" (__oldval), "=&r" (tmp) 161 : "r" (v), "r" (a), "r" (u) 162 : "memory", "p3" 163 ); 164 return __oldval; 165 } 166 167 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) 168 169 #define atomic_inc(v) atomic_add(1, (v)) 170 #define atomic_dec(v) atomic_sub(1, (v)) 171 172 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0) 173 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0) 174 #define atomic_sub_and_test(i, v) (atomic_sub_return(i, (v)) == 0) 175 #define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0) 176 177 #define atomic_inc_return(v) (atomic_add_return(1, v)) 178 #define atomic_dec_return(v) (atomic_sub_return(1, v)) 179 180 #endif 181