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author | Kevin | 2014-11-15 09:58:27 +0800 |
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committer | Kevin | 2014-11-15 09:58:27 +0800 |
commit | 392e8802486cb573b916e746010e141a75f507e6 (patch) | |
tree | 50029aca02c81f087b90336e670b44e510782330 /ANDROID_3.4.5/arch/sparc/include/asm/smpprim.h | |
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init android origin source code
Diffstat (limited to 'ANDROID_3.4.5/arch/sparc/include/asm/smpprim.h')
-rw-r--r-- | ANDROID_3.4.5/arch/sparc/include/asm/smpprim.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/ANDROID_3.4.5/arch/sparc/include/asm/smpprim.h b/ANDROID_3.4.5/arch/sparc/include/asm/smpprim.h new file mode 100644 index 00000000..eb849d86 --- /dev/null +++ b/ANDROID_3.4.5/arch/sparc/include/asm/smpprim.h @@ -0,0 +1,54 @@ +/* + * smpprim.h: SMP locking primitives on the Sparc + * + * God knows we won't be actually using this code for some time + * but I thought I'd write it since I knew how. + * + * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) + */ + +#ifndef __SPARC_SMPPRIM_H +#define __SPARC_SMPPRIM_H + +/* Test and set the unsigned byte at ADDR to 1. Returns the previous + * value. On the Sparc we use the ldstub instruction since it is + * atomic. + */ + +static inline __volatile__ char test_and_set(void *addr) +{ + char state = 0; + + __asm__ __volatile__("ldstub [%0], %1 ! test_and_set\n\t" + "=r" (addr), "=r" (state) : + "0" (addr), "1" (state) : "memory"); + + return state; +} + +/* Initialize a spin-lock. */ +static inline __volatile__ smp_initlock(void *spinlock) +{ + /* Unset the lock. */ + *((unsigned char *) spinlock) = 0; + + return; +} + +/* This routine spins until it acquires the lock at ADDR. */ +static inline __volatile__ smp_lock(void *addr) +{ + while(test_and_set(addr) == 0xff) + ; + + /* We now have the lock */ + return; +} + +/* This routine releases the lock at ADDR. */ +static inline __volatile__ smp_unlock(void *addr) +{ + *((unsigned char *) addr) = 0; +} + +#endif /* !(__SPARC_SMPPRIM_H) */ |