1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #ifndef _ASM_ARC_ATOMIC_H 10 #define _ASM_ARC_ATOMIC_H 11 12 #ifndef __ASSEMBLY__ 13 14 #include <linux/types.h> 15 #include <linux/compiler.h> 16 #include <asm/cmpxchg.h> 17 #include <asm/barrier.h> 18 #include <asm/smp.h> 19 20 #define atomic_read(v) ((v)->counter) 21 22 #ifdef CONFIG_ARC_HAS_LLSC 23 24 #define atomic_set(v, i) (((v)->counter) = (i)) 25 26 #define ATOMIC_OP(op, c_op, asm_op) \ 27 static inline void atomic_##op(int i, atomic_t *v) \ 28 { \ 29 unsigned int temp; \ 30 \ 31 __asm__ __volatile__( \ 32 "1: llock %0, [%1] \n" \ 33 " " #asm_op " %0, %0, %2 \n" \ 34 " scond %0, [%1] \n" \ 35 " bnz 1b \n" \ 36 : "=&r"(temp) /* Early clobber, to prevent reg reuse */ \ 37 : "r"(&v->counter), "ir"(i) \ 38 : "cc"); \ 39 } \ 40 41 #define ATOMIC_OP_RETURN(op, c_op, asm_op) \ 42 static inline int atomic_##op##_return(int i, atomic_t *v) \ 43 { \ 44 unsigned int temp; \ 45 \ 46 __asm__ __volatile__( \ 47 "1: llock %0, [%1] \n" \ 48 " " #asm_op " %0, %0, %2 \n" \ 49 " scond %0, [%1] \n" \ 50 " bnz 1b \n" \ 51 : "=&r"(temp) \ 52 : "r"(&v->counter), "ir"(i) \ 53 : "cc"); \ 54 \ 55 return temp; \ 56 } 57 58 #else /* !CONFIG_ARC_HAS_LLSC */ 59 60 #ifndef CONFIG_SMP 61 62 /* violating atomic_xxx API locking protocol in UP for optimization sake */ 63 #define atomic_set(v, i) (((v)->counter) = (i)) 64 65 #else 66 67 static inline void atomic_set(atomic_t *v, int i) 68 { 69 /* 70 * Independent of hardware support, all of the atomic_xxx() APIs need 71 * to follow the same locking rules to make sure that a "hardware" 72 * atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn 73 * sequence 74 * 75 * Thus atomic_set() despite being 1 insn (and seemingly atomic) 76 * requires the locking. 77 */ 78 unsigned long flags; 79 80 atomic_ops_lock(flags); 81 v->counter = i; 82 atomic_ops_unlock(flags); 83 } 84 85 #endif 86 87 /* 88 * Non hardware assisted Atomic-R-M-W 89 * Locking would change to irq-disabling only (UP) and spinlocks (SMP) 90 */ 91 92 #define ATOMIC_OP(op, c_op, asm_op) \ 93 static inline void atomic_##op(int i, atomic_t *v) \ 94 { \ 95 unsigned long flags; \ 96 \ 97 atomic_ops_lock(flags); \ 98 v->counter c_op i; \ 99 atomic_ops_unlock(flags); \ 100 } 101 102 #define ATOMIC_OP_RETURN(op, c_op) \ 103 static inline int atomic_##op##_return(int i, atomic_t *v) \ 104 { \ 105 unsigned long flags; \ 106 unsigned long temp; \ 107 \ 108 atomic_ops_lock(flags); \ 109 temp = v->counter; \ 110 temp c_op i; \ 111 v->counter = temp; \ 112 atomic_ops_unlock(flags); \ 113 \ 114 return temp; \ 115 } 116 117 #endif /* !CONFIG_ARC_HAS_LLSC */ 118 119 #define ATOMIC_OPS(op, c_op, asm_op) \ 120 ATOMIC_OP(op, c_op, asm_op) \ 121 ATOMIC_OP_RETURN(op, c_op, asm_op) 122 123 ATOMIC_OPS(add, +=, add) 124 ATOMIC_OPS(sub, -=, sub) 125 ATOMIC_OP(and, &=, and) 126 127 #define atomic_clear_mask(mask, v) atomic_and(~(mask), (v)) 128 129 #undef ATOMIC_OPS 130 #undef ATOMIC_OP_RETURN 131 #undef ATOMIC_OP 132 133 /** 134 * __atomic_add_unless - add unless the number is a given value 135 * @v: pointer of type atomic_t 136 * @a: the amount to add to v... 137 * @u: ...unless v is equal to u. 138 * 139 * Atomically adds @a to @v, so long as it was not @u. 140 * Returns the old value of @v 141 */ 142 #define __atomic_add_unless(v, a, u) \ 143 ({ \ 144 int c, old; \ 145 c = atomic_read(v); \ 146 while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\ 147 c = old; \ 148 c; \ 149 }) 150 151 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) 152 153 #define atomic_inc(v) atomic_add(1, v) 154 #define atomic_dec(v) atomic_sub(1, v) 155 156 #define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0) 157 #define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0) 158 #define atomic_inc_return(v) atomic_add_return(1, (v)) 159 #define atomic_dec_return(v) atomic_sub_return(1, (v)) 160 #define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0) 161 162 #define atomic_add_negative(i, v) (atomic_add_return(i, v) < 0) 163 164 #define ATOMIC_INIT(i) { (i) } 165 166 #include <asm-generic/atomic64.h> 167 168 #endif 169 170 #endif 171