include/asm-alpha/spinlock.h

   1 #ifndef _ALPHA_SPINLOCK_H
   2 #define _ALPHA_SPINLOCK_H
   3
   4 #include <linux/config.h>
   5 #include <asm/system.h>
   6 #include <linux/kernel.h>
   7 #include <asm/current.h>
   8
   9 /*
  10  * Simple spin lock operations.  There are two variants, one clears IRQ's
  11  * on the local processor, one does not.
  12  *
  13  * We make no fairness assumptions. They have a cost.
  14  */
  15
  16 #define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
  17 #define __raw_spin_is_locked(x) ((x)->lock != 0)
  18 #define __raw_spin_unlock_wait(x) \
  19                 do { cpu_relax(); } while ((x)->lock)
  20
  21 static inline void __raw_spin_unlock(raw_spinlock_t * lock)
  22 {
  23         mb();
  24         lock->lock = 0;
  25 }
  26
  27 static inline void __raw_spin_lock(raw_spinlock_t * lock)
  28 {
  29         long tmp;
  30
  31         __asm__ __volatile__(
  32         "1:     ldl_l   %0,%1\n"
  33         "       bne     %0,2f\n"
  34         "       lda     %0,1\n"
  35         "       stl_c   %0,%1\n"
  36         "       beq     %0,2f\n"
  37         "       mb\n"
  38         ".subsection 2\n"
  39         "2:     ldl     %0,%1\n"
  40         "       bne     %0,2b\n"
  41         "       br      1b\n"
  42         ".previous"
  43         : "=&r" (tmp), "=m" (lock->lock)
  44         : "m"(lock->lock) : "memory");
  45 }
  46
  47 static inline int __raw_spin_trylock(raw_spinlock_t *lock)
  48 {
  49         return !test_and_set_bit(0, &lock->lock);
  50 }
  51
  52 /***********************************************************/
  53
  54 static inline int __raw_read_can_lock(raw_rwlock_t *lock)
  55 {
  56         return (lock->lock & 1) == 0;
  57 }
  58
  59 static inline int __raw_write_can_lock(raw_rwlock_t *lock)
  60 {
  61         return lock->lock == 0;
  62 }
  63
  64 static inline void __raw_read_lock(raw_rwlock_t *lock)
  65 {
  66         long regx;
  67
  68         __asm__ __volatile__(
  69         "1:     ldl_l   %1,%0\n"
  70         "       blbs    %1,6f\n"
  71         "       subl    %1,2,%1\n"
  72         "       stl_c   %1,%0\n"
  73         "       beq     %1,6f\n"
  74         "       mb\n"
  75         ".subsection 2\n"
  76         "6:     ldl     %1,%0\n"
  77         "       blbs    %1,6b\n"
  78         "       br      1b\n"
  79         ".previous"
  80         : "=m" (*lock), "=&r" (regx)
  81         : "m" (*lock) : "memory");
  82 }
  83
  84 static inline void __raw_write_lock(raw_rwlock_t *lock)
  85 {
  86         long regx;
  87
  88         __asm__ __volatile__(
  89         "1:     ldl_l   %1,%0\n"
  90         "       bne     %1,6f\n"
  91         "       lda     %1,1\n"
  92         "       stl_c   %1,%0\n"
  93         "       beq     %1,6f\n"
  94         "       mb\n"
  95         ".subsection 2\n"
  96         "6:     ldl     %1,%0\n"
  97         "       bne     %1,6b\n"
  98         "       br      1b\n"
  99         ".previous"
 100         : "=m" (*lock), "=&r" (regx)
 101         : "m" (*lock) : "memory");
 102 }
 103
 104 static inline int __raw_read_trylock(raw_rwlock_t * lock)
 105 {
 106         long regx;
 107         int success;
 108
 109         __asm__ __volatile__(
 110         "1:     ldl_l   %1,%0\n"
 111         "       lda     %2,0\n"
 112         "       blbs    %1,2f\n"
 113         "       subl    %1,2,%2\n"
 114         "       stl_c   %2,%0\n"
 115         "       beq     %2,6f\n"
 116         "2:     mb\n"
 117         ".subsection 2\n"
 118         "6:     br      1b\n"
 119         ".previous"
 120         : "=m" (*lock), "=&r" (regx), "=&r" (success)
 121         : "m" (*lock) : "memory");
 122
 123         return success;
 124 }
 125
 126 static inline int __raw_write_trylock(raw_rwlock_t * lock)
 127 {
 128         long regx;
 129         int success;
 130
 131         __asm__ __volatile__(
 132         "1:     ldl_l   %1,%0\n"
 133         "       lda     %2,0\n"
 134         "       bne     %1,2f\n"
 135         "       lda     %2,1\n"
 136         "       stl_c   %2,%0\n"
 137         "       beq     %2,6f\n"
 138         "2:     mb\n"
 139         ".subsection 2\n"
 140         "6:     br      1b\n"
 141         ".previous"
 142         : "=m" (*lock), "=&r" (regx), "=&r" (success)
 143         : "m" (*lock) : "memory");
 144
 145         return success;
 146 }
 147
 148 static inline void __raw_read_unlock(raw_rwlock_t * lock)
 149 {
 150         long regx;
 151         __asm__ __volatile__(
 152         "       mb\n"
 153         "1:     ldl_l   %1,%0\n"
 154         "       addl    %1,2,%1\n"
 155         "       stl_c   %1,%0\n"
 156         "       beq     %1,6f\n"
 157         ".subsection 2\n"
 158         "6:     br      1b\n"
 159         ".previous"
 160         : "=m" (*lock), "=&r" (regx)
 161         : "m" (*lock) : "memory");
 162 }
 163
 164 static inline void __raw_write_unlock(raw_rwlock_t * lock)
 165 {
 166         mb();
 167         lock->lock = 0;
 168 }
 169
 170 #endif /* _ALPHA_SPINLOCK_H */