Kernel/arch/arm7/include/lock.h

   1 /*
   2  * Acess2
   3  * ARM7 Architecture
   4  *
   5  * lock.h - Hardware level spinlocks
   6  */
   7 #ifndef _LOCK_H_
   8 #define _LOCK_H_
   9
  10 // === CODE ===
  11 struct sShortSpinlock {
  12          int    Lock;
  13 };
  14
  15 // --- Spinlocks ---
  16 static inline int IS_LOCKED(struct sShortSpinlock *Lock)
  17 {
  18         return !!Lock->Lock;
  19 }
  20
  21 static inline int CPU_HAS_LOCK(struct sShortSpinlock *Lock)
  22 {
  23         // TODO: Handle multiple CPUs
  24         return !!Lock->Lock;
  25 }
  26
  27 static inline int SHORTLOCK(struct sShortSpinlock *Lock)
  28 {
  29         #if 0
  30         while( __sync_lock_test_and_set( &Lock->Lock, 1 ) == 1 );
  31         #endif
  32         #if 1
  33         while( Lock->Lock )     ;
  34         Lock->Lock = 1;
  35         #endif
  36         #if 0
  37         // Shamelessly copied from linux (/arch/arm/include/asm/spinlock.h) until I can fix stuff
  38         Uint    tmp;
  39         __asm__ __volatile__ (
  40         "1:     ldrex   %0, [%1]\n"
  41         "       teq     %0, #0\n"
  42         "       strexeq %0, %2, [%1]\n" // Magic? TODO: Look up
  43         "       teqeq   %0, #0\n"
  44         "       bne     1b"
  45                 : "=&r" (tmp)   // Temp
  46                 : "r" (&Lock->Lock), "r" (1)
  47                 : "cc"  // Condition codes clobbered
  48                 );
  49         #endif
  50         return 1;
  51 }
  52
  53 static inline void SHORTREL(struct sShortSpinlock *Lock)
  54 {
  55         Lock->Lock = 0;
  56 }
  57
  58 #endif
  59