1/* 2 * Atomic operations that C can't guarantee us. Useful for 3 * resource counting etc. 4 * 5 * But use these as seldom as possible since they are slower than 6 * regular operations. 7 * 8 * Copyright (C) 2004-2006 Atmel Corporation 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14#ifndef __ASM_AVR32_CMPXCHG_H 15#define __ASM_AVR32_CMPXCHG_H 16 17#define xchg(ptr,x) \ 18 ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) 19 20extern void __xchg_called_with_bad_pointer(void); 21 22static inline unsigned long xchg_u32(u32 val, volatile u32 *m) 23{ 24 u32 ret; 25 26 asm volatile("xchg %[ret], %[m], %[val]" 27 : [ret] "=&r"(ret), "=m"(*m) 28 : "m"(*m), [m] "r"(m), [val] "r"(val) 29 : "memory"); 30 return ret; 31} 32 33static inline unsigned long __xchg(unsigned long x, 34 volatile void *ptr, 35 int size) 36{ 37 switch(size) { 38 case 4: 39 return xchg_u32(x, ptr); 40 default: 41 __xchg_called_with_bad_pointer(); 42 return x; 43 } 44} 45 46static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old, 47 unsigned long new) 48{ 49 __u32 ret; 50 51 asm volatile( 52 "1: ssrf 5\n" 53 " ld.w %[ret], %[m]\n" 54 " cp.w %[ret], %[old]\n" 55 " brne 2f\n" 56 " stcond %[m], %[new]\n" 57 " brne 1b\n" 58 "2:\n" 59 : [ret] "=&r"(ret), [m] "=m"(*m) 60 : "m"(m), [old] "ir"(old), [new] "r"(new) 61 : "memory", "cc"); 62 return ret; 63} 64 65extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels( 66 volatile int * m, unsigned long old, unsigned long new); 67#define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels 68 69/* This function doesn't exist, so you'll get a linker error 70 if something tries to do an invalid cmpxchg(). */ 71extern void __cmpxchg_called_with_bad_pointer(void); 72 73static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, 74 unsigned long new, int size) 75{ 76 switch (size) { 77 case 4: 78 return __cmpxchg_u32(ptr, old, new); 79 case 8: 80 return __cmpxchg_u64(ptr, old, new); 81 } 82 83 __cmpxchg_called_with_bad_pointer(); 84 return old; 85} 86 87#define cmpxchg(ptr, old, new) \ 88 ((typeof(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), \ 89 (unsigned long)(new), \ 90 sizeof(*(ptr)))) 91 92#include <asm-generic/cmpxchg-local.h> 93 94static inline unsigned long __cmpxchg_local(volatile void *ptr, 95 unsigned long old, 96 unsigned long new, int size) 97{ 98 switch (size) { 99 case 4: 100 return __cmpxchg_u32(ptr, old, new); 101 default: 102 return __cmpxchg_local_generic(ptr, old, new, size); 103 } 104 105 return old; 106} 107 108#define cmpxchg_local(ptr, old, new) \ 109 ((typeof(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(old), \ 110 (unsigned long)(new), \ 111 sizeof(*(ptr)))) 112 113#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) 114 115#endif /* __ASM_AVR32_CMPXCHG_H */ 116