Kernel/arm7 - Serial works (realview-pb-a8)

[tpg/acess2.git] / Kernel / arch / arm7 / include / lock.h

diff --git a/Kernel/arch/arm7/include/lock.h b/Kernel/arch/arm7/include/lock.h
index e270145..627726b 100644 (file)
--- a/Kernel/arch/arm7/include/lock.h
+++ b/Kernel/arch/arm7/include/lock.h
@@ -26,26 +26,27 @@ static inline int CPU_HAS_LOCK(struct sShortSpinlock *Lock)
 
 static inline int SHORTLOCK(struct sShortSpinlock *Lock)
 {
-       #if 0
-       while( __sync_lock_test_and_set( &Lock->Lock, 1 ) == 1 );
-       #endif
        #if 1
-       while( Lock->Lock )     ;
-       Lock->Lock = 1;
-       #endif
-       #if 0
-       // Shamelessly copied from linux (/arch/arm/include/asm/spinlock.h) until I can fix stuff
+       // Coped from linux, yes, but I know what it does now :)
        Uint    tmp;
        __asm__ __volatile__ (
-       "1:     ldrex   %0, [%1]\n"
-       "       teq     %0, #0\n"
-       "       strexeq %0, %2, [%1]\n" // Magic? TODO: Look up
-       "       teqeq   %0, #0\n"
-       "       bne     1b"
+       "1:     ldrex   %0, [%1]\n"     // Exclusive LOAD
+       "       teq     %0, #0\n"       // Check if zero
+       "       strexeq %0, %2, [%1]\n" // Set to one if it is zero (releasing lock on the memory)
+       "       teqeq   %0, #0\n"       // If the lock was avaliable, check if the write succeeded
+       "       bne     1b"     // If the lock was unavaliable, or the write failed, loop
                : "=&r" (tmp)   // Temp
                : "r" (&Lock->Lock), "r" (1)
                : "cc"  // Condition codes clobbered
                );
+       #else
+        int    v = 1;
+       while( v )
+               __asm__ __volatile__ (
+                       "swp %0, [%1]"
+                       : "=r" (v) : "r" (&Lock->Lock)
+                       : "cc"
+                       );
        #endif
        return 1;
 }