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#ifndef _ASM_METAG_BARRIER_H
#define _ASM_METAG_BARRIER_H
#include <asm/metag_mem.h>
#define nop() asm volatile ("NOP")
#ifdef CONFIG_METAG_META21
/* 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 CONFIG_METAG_SMP_WRITE_REORDERING
/*
* 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 CONFIG_SMP
#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 */
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