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   1 /* atomic.h: atomic operation emulation for FR-V
   2  *
   3  * For an explanation of how atomic ops work in this arch, see:
   4  *   Documentation/frv/atomic-ops.txt
   5  *
   6  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   7  * Written by David Howells (dhowells@redhat.com)
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  */
  14 #ifndef _ASM_ATOMIC_H
  15 #define _ASM_ATOMIC_H
  16
  17 #include <linux/types.h>
  18 #include <asm/spr-regs.h>
  19 #include <asm/system.h>
  20
  21 #ifdef CONFIG_SMP
  22 #error not SMP safe
  23 #endif
  24
  25 /*
  26  * Atomic operations that C can't guarantee us.  Useful for
  27  * resource counting etc..
  28  *
  29  * We do not have SMP systems, so we don't have to deal with that.
  30  */
  31
  32 /* Atomic operations are already serializing */
  33 #define smp_mb__before_atomic_dec()     barrier()
  34 #define smp_mb__after_atomic_dec()      barrier()
  35 #define smp_mb__before_atomic_inc()     barrier()
  36 #define smp_mb__after_atomic_inc()      barrier()
  37
  38 #define ATOMIC_INIT(i)          { (i) }
  39 #define atomic_read(v)          ((v)->counter)
  40 #define atomic_set(v, i)        (((v)->counter) = (i))
  41
  42 #ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
  43 static inline int atomic_add_return(int i, atomic_t *v)
  44 {
  45         unsigned long val;
  46
  47         asm("0:                                         \n"
  48             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
  49             "   ckeq            icc3,cc7                \n"
  50             "   ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
  51             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
  52             "   add%I2          %1,%2,%1                \n"
  53             "   cst.p           %1,%M0          ,cc3,#1 \n"
  54             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
  55             "   beq             icc3,#0,0b              \n"
  56             : "+U"(v->counter), "=&r"(val)
  57             : "NPr"(i)
  58             : "memory", "cc7", "cc3", "icc3"
  59             );
  60
  61         return val;
  62 }
  63
  64 static inline int atomic_sub_return(int i, atomic_t *v)
  65 {
  66         unsigned long val;
  67
  68         asm("0:                                         \n"
  69             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
  70             "   ckeq            icc3,cc7                \n"
  71             "   ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
  72             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
  73             "   sub%I2          %1,%2,%1                \n"
  74             "   cst.p           %1,%M0          ,cc3,#1 \n"
  75             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
  76             "   beq             icc3,#0,0b              \n"
  77             : "+U"(v->counter), "=&r"(val)
  78             : "NPr"(i)
  79             : "memory", "cc7", "cc3", "icc3"
  80             );
  81
  82         return val;
  83 }
  84
  85 #else
  86
  87 extern int atomic_add_return(int i, atomic_t *v);
  88 extern int atomic_sub_return(int i, atomic_t *v);
  89
  90 #endif
  91
  92 static inline int atomic_add_negative(int i, atomic_t *v)
  93 {
  94         return atomic_add_return(i, v) < 0;
  95 }
  96
  97 static inline void atomic_add(int i, atomic_t *v)
  98 {
  99         atomic_add_return(i, v);
 100 }
 101
 102 static inline void atomic_sub(int i, atomic_t *v)
 103 {
 104         atomic_sub_return(i, v);
 105 }
 106
 107 static inline void atomic_inc(atomic_t *v)
 108 {
 109         atomic_add_return(1, v);
 110 }
 111
 112 static inline void atomic_dec(atomic_t *v)
 113 {
 114         atomic_sub_return(1, v);
 115 }
 116
 117 #define atomic_dec_return(v)            atomic_sub_return(1, (v))
 118 #define atomic_inc_return(v)            atomic_add_return(1, (v))
 119
 120 #define atomic_sub_and_test(i,v)        (atomic_sub_return((i), (v)) == 0)
 121 #define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
 122 #define atomic_inc_and_test(v)          (atomic_add_return(1, (v)) == 0)
 123
 124 /*****************************************************************************/
 125 /*
 126  * exchange value with memory
 127  */
 128 #ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
 129
 130 #define xchg(ptr, x)                                                            \
 131 ({                                                                              \
 132         __typeof__(ptr) __xg_ptr = (ptr);                                       \
 133         __typeof__(*(ptr)) __xg_orig;                                           \
 134                                                                                 \
 135         switch (sizeof(__xg_orig)) {                                            \
 136         case 4:                                                                 \
 137                 asm volatile(                                                   \
 138                         "swap%I0 %M0,%1"                                        \
 139                         : "+m"(*__xg_ptr), "=r"(__xg_orig)                      \
 140                         : "1"(x)                                                \
 141                         : "memory"                                              \
 142                         );                                                      \
 143                 break;                                                          \
 144                                                                                 \
 145         default:                                                                \
 146                 __xg_orig = (__typeof__(__xg_orig))0;                           \
 147                 asm volatile("break");                                          \
 148                 break;                                                          \
 149         }                                                                       \
 150                                                                                 \
 151         __xg_orig;                                                              \
 152 })
 153
 154 #else
 155
 156 extern uint32_t __xchg_32(uint32_t i, volatile void *v);
 157
 158 #define xchg(ptr, x)                                                                            \
 159 ({                                                                                              \
 160         __typeof__(ptr) __xg_ptr = (ptr);                                                       \
 161         __typeof__(*(ptr)) __xg_orig;                                                           \
 162                                                                                                 \
 163         switch (sizeof(__xg_orig)) {                                                            \
 164         case 4: __xg_orig = (__typeof__(*(ptr))) __xchg_32((uint32_t) x, __xg_ptr);     break;  \
 165         default:                                                                                \
 166                 __xg_orig = (__typeof__(__xg_orig))0;                                                                   \
 167                 asm volatile("break");                                                          \
 168                 break;                                                                          \
 169         }                                                                                       \
 170         __xg_orig;                                                                              \
 171 })
 172
 173 #endif
 174
 175 #define tas(ptr) (xchg((ptr), 1))
 176
 177 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
 178 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 179
 180 static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
 181 {
 182         int c, old;
 183         c = atomic_read(v);
 184         for (;;) {
 185                 if (unlikely(c == (u)))
 186                         break;
 187                 old = atomic_cmpxchg((v), c, c + (a));
 188                 if (likely(old == c))
 189                         break;
 190                 c = old;
 191         }
 192         return c != (u);
 193 }
 194
 195 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 196
 197 #include <asm-generic/atomic.h>
 198 #endif /* _ASM_ATOMIC_H */