include/asm-ppc/spinlock.h

   1 #ifndef __ASM_SPINLOCK_H
   2 #define __ASM_SPINLOCK_H
   3
   4 #include <asm/system.h>
   5
   6 /*
   7  * Simple spin lock operations.
   8  */
   9
  10 typedef struct {
  11         volatile unsigned long lock;
  12 #ifdef CONFIG_DEBUG_SPINLOCK
  13         volatile unsigned long owner_pc;
  14         volatile unsigned long owner_cpu;
  15 #endif
  16 #ifdef CONFIG_PREEMPT
  17         unsigned int break_lock;
  18 #endif
  19 } spinlock_t;
  20
  21 #ifdef __KERNEL__
  22 #ifdef CONFIG_DEBUG_SPINLOCK
  23 #define SPINLOCK_DEBUG_INIT     , 0, 0
  24 #else
  25 #define SPINLOCK_DEBUG_INIT     /* */
  26 #endif
  27
  28 #define SPIN_LOCK_UNLOCKED      (spinlock_t) { 0 SPINLOCK_DEBUG_INIT }
  29
  30 #define spin_lock_init(x)       do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
  31 #define spin_is_locked(x)       ((x)->lock != 0)
  32 #define spin_unlock_wait(x)     do { barrier(); } while(spin_is_locked(x))
  33 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
  34
  35 #ifndef CONFIG_DEBUG_SPINLOCK
  36
  37 static inline void _raw_spin_lock(spinlock_t *lock)
  38 {
  39         unsigned long tmp;
  40
  41         __asm__ __volatile__(
  42         "b      1f              # spin_lock\n\
  43 2:      lwzx    %0,0,%1\n\
  44         cmpwi   0,%0,0\n\
  45         bne+    2b\n\
  46 1:      lwarx   %0,0,%1\n\
  47         cmpwi   0,%0,0\n\
  48         bne-    2b\n"
  49         PPC405_ERR77(0,%1)
  50 "       stwcx.  %2,0,%1\n\
  51         bne-    2b\n\
  52         isync"
  53         : "=&r"(tmp)
  54         : "r"(&lock->lock), "r"(1)
  55         : "cr0", "memory");
  56 }
  57
  58 static inline void _raw_spin_unlock(spinlock_t *lock)
  59 {
  60         __asm__ __volatile__("eieio             # spin_unlock": : :"memory");
  61         lock->lock = 0;
  62 }
  63
  64 #define _raw_spin_trylock(l) (!test_and_set_bit(0,&(l)->lock))
  65
  66 #else
  67
  68 extern void _raw_spin_lock(spinlock_t *lock);
  69 extern void _raw_spin_unlock(spinlock_t *lock);
  70 extern int _raw_spin_trylock(spinlock_t *lock);
  71
  72 #endif
  73
  74 /*
  75  * Read-write spinlocks, allowing multiple readers
  76  * but only one writer.
  77  *
  78  * NOTE! it is quite common to have readers in interrupts
  79  * but no interrupt writers. For those circumstances we
  80  * can "mix" irq-safe locks - any writer needs to get a
  81  * irq-safe write-lock, but readers can get non-irqsafe
  82  * read-locks.
  83  */
  84 typedef struct {
  85         volatile signed int lock;
  86 #ifdef CONFIG_PREEMPT
  87         unsigned int break_lock;
  88 #endif
  89 } rwlock_t;
  90
  91 #define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
  92 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
  93
  94 #define read_can_lock(rw)       ((rw)->lock >= 0)
  95 #define write_can_lock(rw)      (!(rw)->lock)
  96
  97 #ifndef CONFIG_DEBUG_SPINLOCK
  98
  99 static __inline__ int _raw_read_trylock(rwlock_t *rw)
 100 {
 101         signed int tmp;
 102
 103         __asm__ __volatile__(
 104 "2:     lwarx   %0,0,%1         # read_trylock\n\
 105         addic.  %0,%0,1\n\
 106         ble-    1f\n"
 107         PPC405_ERR77(0,%1)
 108 "       stwcx.  %0,0,%1\n\
 109         bne-    2b\n\
 110         isync\n\
 111 1:"
 112         : "=&r"(tmp)
 113         : "r"(&rw->lock)
 114         : "cr0", "memory");
 115
 116         return tmp > 0;
 117 }
 118
 119 static __inline__ void _raw_read_lock(rwlock_t *rw)
 120 {
 121         signed int tmp;
 122
 123         __asm__ __volatile__(
 124         "b      2f              # read_lock\n\
 125 1:      lwzx    %0,0,%1\n\
 126         cmpwi   0,%0,0\n\
 127         blt+    1b\n\
 128 2:      lwarx   %0,0,%1\n\
 129         addic.  %0,%0,1\n\
 130         ble-    1b\n"
 131         PPC405_ERR77(0,%1)
 132 "       stwcx.  %0,0,%1\n\
 133         bne-    2b\n\
 134         isync"
 135         : "=&r"(tmp)
 136         : "r"(&rw->lock)
 137         : "cr0", "memory");
 138 }
 139
 140 static __inline__ void _raw_read_unlock(rwlock_t *rw)
 141 {
 142         signed int tmp;
 143
 144         __asm__ __volatile__(
 145         "eieio                  # read_unlock\n\
 146 1:      lwarx   %0,0,%1\n\
 147         addic   %0,%0,-1\n"
 148         PPC405_ERR77(0,%1)
 149 "       stwcx.  %0,0,%1\n\
 150         bne-    1b"
 151         : "=&r"(tmp)
 152         : "r"(&rw->lock)
 153         : "cr0", "memory");
 154 }
 155
 156 static __inline__ int _raw_write_trylock(rwlock_t *rw)
 157 {
 158         signed int tmp;
 159
 160         __asm__ __volatile__(
 161 "2:     lwarx   %0,0,%1         # write_trylock\n\
 162         cmpwi   0,%0,0\n\
 163         bne-    1f\n"
 164         PPC405_ERR77(0,%1)
 165 "       stwcx.  %2,0,%1\n\
 166         bne-    2b\n\
 167         isync\n\
 168 1:"
 169         : "=&r"(tmp)
 170         : "r"(&rw->lock), "r"(-1)
 171         : "cr0", "memory");
 172
 173         return tmp == 0;
 174 }
 175
 176 static __inline__ void _raw_write_lock(rwlock_t *rw)
 177 {
 178         signed int tmp;
 179
 180         __asm__ __volatile__(
 181         "b      2f              # write_lock\n\
 182 1:      lwzx    %0,0,%1\n\
 183         cmpwi   0,%0,0\n\
 184         bne+    1b\n\
 185 2:      lwarx   %0,0,%1\n\
 186         cmpwi   0,%0,0\n\
 187         bne-    1b\n"
 188         PPC405_ERR77(0,%1)
 189 "       stwcx.  %2,0,%1\n\
 190         bne-    2b\n\
 191         isync"
 192         : "=&r"(tmp)
 193         : "r"(&rw->lock), "r"(-1)
 194         : "cr0", "memory");
 195 }
 196
 197 static __inline__ void _raw_write_unlock(rwlock_t *rw)
 198 {
 199         __asm__ __volatile__("eieio             # write_unlock": : :"memory");
 200         rw->lock = 0;
 201 }
 202
 203 #else
 204
 205 extern void _raw_read_lock(rwlock_t *rw);
 206 extern void _raw_read_unlock(rwlock_t *rw);
 207 extern void _raw_write_lock(rwlock_t *rw);
 208 extern void _raw_write_unlock(rwlock_t *rw);
 209 extern int _raw_read_trylock(rwlock_t *rw);
 210 extern int _raw_write_trylock(rwlock_t *rw);
 211
 212 #endif
 213
 214 #endif /* __ASM_SPINLOCK_H */
 215 #endif /* __KERNEL__ */