#ifndef _ASM_METAG_BARRIER_H #define _ASM_METAG_BARRIER_H #include <asm/metag_mem.h> #define nop() asm volatile ("NOP") #ifdef [31mCONFIG_METAG_META21[0m /* HTP and above have a system event to fence writes */ static inline void wr_fence(void) { volatile int *flushptr = (volatile int *) LINSYSEVENT_WR_FENCE; barrier(); *flushptr = 0; barrier(); } #else /* CONFIG_METAG_META21 */ /* * ATP doesn't have system event to fence writes, so it is necessary to flush * the processor write queues as well as possibly the write combiner (depending * on the page being written). * To ensure the write queues are flushed we do 4 writes to a system event * register (in this case write combiner flush) which will also flush the write * combiner. */ static inline void wr_fence(void) { volatile int *flushptr = (volatile int *) LINSYSEVENT_WR_COMBINE_FLUSH; barrier(); *flushptr = 0; *flushptr = 0; *flushptr = 0; *flushptr = 0; barrier(); } #endif /* !CONFIG_METAG_META21 */ /* flush writes through the write combiner */ #define mb() wr_fence() #define rmb() barrier() #define wmb() mb() #ifdef [31mCONFIG_METAG_SMP_WRITE_REORDERING[0m /* * Write to the atomic memory unlock system event register (command 0). This is * needed before a write to shared memory in a critical section, to prevent * external reordering of writes before the fence on other threads with writes * after the fence on this thread (and to prevent the ensuing cache-memory * incoherence). It is therefore ineffective if used after and on the same * thread as a write. */ static inline void metag_fence(void) { volatile int *flushptr = (volatile int *) LINSYSEVENT_WR_ATOMIC_UNLOCK; barrier(); *flushptr = 0; barrier(); } #define __smp_mb() metag_fence() #define __smp_rmb() metag_fence() #define __smp_wmb() barrier() #else #define metag_fence() do { } while (0) #define __smp_mb() barrier() #define __smp_rmb() barrier() #define __smp_wmb() barrier() #endif #ifdef [31mCONFIG_SMP[0m #define fence() metag_fence() #else #define fence() do { } while (0) #endif #define __smp_mb__before_atomic() barrier() #define __smp_mb__after_atomic() barrier() #include <asm-generic/barrier.h> #endif /* _ASM_METAG_BARRIER_H */ |