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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 typedef struct {
  39         int counter;
  40 } atomic_t;
  41
  42 #define ATOMIC_INIT(i)          { (i) }
  43 #define atomic_read(v)          ((v)->counter)
  44 #define atomic_set(v, i)        (((v)->counter) = (i))
  45
  46 #ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
  47 static inline int atomic_add_return(int i, atomic_t *v)
  48 {
  49         unsigned long val;
  50
  51         asm("0:                                         \n"
  52             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
  53             "   ckeq            icc3,cc7                \n"
  54             "   ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
  55             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
  56             "   add%I2          %1,%2,%1                \n"
  57             "   cst.p           %1,%M0          ,cc3,#1 \n"
  58             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
  59             "   beq             icc3,#0,0b              \n"
  60             : "+U"(v->counter), "=&r"(val)
  61             : "NPr"(i)
  62             : "memory", "cc7", "cc3", "icc3"
  63             );
  64
  65         return val;
  66 }
  67
  68 static inline int atomic_sub_return(int i, atomic_t *v)
  69 {
  70         unsigned long val;
  71
  72         asm("0:                                         \n"
  73             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
  74             "   ckeq            icc3,cc7                \n"
  75             "   ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
  76             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
  77             "   sub%I2          %1,%2,%1                \n"
  78             "   cst.p           %1,%M0          ,cc3,#1 \n"
  79             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
  80             "   beq             icc3,#0,0b              \n"
  81             : "+U"(v->counter), "=&r"(val)
  82             : "NPr"(i)
  83             : "memory", "cc7", "cc3", "icc3"
  84             );
  85
  86         return val;
  87 }
  88
  89 #else
  90
  91 extern int atomic_add_return(int i, atomic_t *v);
  92 extern int atomic_sub_return(int i, atomic_t *v);
  93
  94 #endif
  95
  96 static inline int atomic_add_negative(int i, atomic_t *v)
  97 {
  98         return atomic_add_return(i, v) < 0;
  99 }
 100
 101 static inline void atomic_add(int i, atomic_t *v)
 102 {
 103         atomic_add_return(i, v);
 104 }
 105
 106 static inline void atomic_sub(int i, atomic_t *v)
 107 {
 108         atomic_sub_return(i, v);
 109 }
 110
 111 static inline void atomic_inc(atomic_t *v)
 112 {
 113         atomic_add_return(1, v);
 114 }
 115
 116 static inline void atomic_dec(atomic_t *v)
 117 {
 118         atomic_sub_return(1, v);
 119 }
 120
 121 #define atomic_dec_return(v)            atomic_sub_return(1, (v))
 122 #define atomic_inc_return(v)            atomic_add_return(1, (v))
 123
 124 #define atomic_sub_and_test(i,v)        (atomic_sub_return((i), (v)) == 0)
 125 #define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
 126 #define atomic_inc_and_test(v)          (atomic_add_return(1, (v)) == 0)
 127
 128 /*****************************************************************************/
 129 /*
 130  * exchange value with memory
 131  */
 132 #ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
 133
 134 #define xchg(ptr, x)                                                            \
 135 ({                                                                              \
 136         __typeof__(ptr) __xg_ptr = (ptr);                                       \
 137         __typeof__(*(ptr)) __xg_orig;                                           \
 138                                                                                 \
 139         switch (sizeof(__xg_orig)) {                                            \
 140         case 4:                                                                 \
 141                 asm volatile(                                                   \
 142                         "swap%I0 %M0,%1"                                        \
 143                         : "+m"(*__xg_ptr), "=r"(__xg_orig)                      \
 144                         : "1"(x)                                                \
 145                         : "memory"                                              \
 146                         );                                                      \
 147                 break;                                                          \
 148                                                                                 \
 149         default:                                                                \
 150                 __xg_orig = (__typeof__(__xg_orig))0;                           \
 151                 asm volatile("break");                                          \
 152                 break;                                                          \
 153         }                                                                       \
 154                                                                                 \
 155         __xg_orig;                                                              \
 156 })
 157
 158 #else
 159
 160 extern uint32_t __xchg_32(uint32_t i, volatile void *v);
 161
 162 #define xchg(ptr, x)                                                                            \
 163 ({                                                                                              \
 164         __typeof__(ptr) __xg_ptr = (ptr);                                                       \
 165         __typeof__(*(ptr)) __xg_orig;                                                           \
 166                                                                                                 \
 167         switch (sizeof(__xg_orig)) {                                                            \
 168         case 4: __xg_orig = (__typeof__(*(ptr))) __xchg_32((uint32_t) x, __xg_ptr);     break;  \
 169         default:                                                                                \
 170                 __xg_orig = (__typeof__(__xg_orig))0;                                                                   \
 171                 asm volatile("break");                                                          \
 172                 break;                                                                          \
 173         }                                                                                       \
 174         __xg_orig;                                                                              \
 175 })
 176
 177 #endif
 178
 179 #define tas(ptr) (xchg((ptr), 1))
 180
 181 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
 182 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 183
 184 static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
 185 {
 186         int c, old;
 187         c = atomic_read(v);
 188         for (;;) {
 189                 if (unlikely(c == (u)))
 190                         break;
 191                 old = atomic_cmpxchg((v), c, c + (a));
 192                 if (likely(old == c))
 193                         break;
 194                 c = old;
 195         }
 196         return c != (u);
 197 }
 198
 199 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 200
 201 #include <asm-generic/atomic.h>
 202 #endif /* _ASM_ATOMIC_H */