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path: root/arch/metag/include/asm/cmpxchg_irq.h
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2013-03-02metag: Atomics, locks and bitopsJames Hogan
Add header files to implement Meta hardware thread locks (used by some other atomic operations), atomics, spinlocks, and bitops. There are 2 main types of atomic primitives for metag (in addition to IRQs off on UP): - LOCK instructions provide locking between hardware threads. - LNKGET/LNKSET instructions provide load-linked/store-conditional operations allowing for lighter weight atomics on Meta2 LOCK instructions allow for hardware threads to acquire voluntary or exclusive hardware thread locks: - LOCK0 releases exclusive and voluntary lock from the running hardware thread. - LOCK1 acquires the voluntary hardware lock, blocking until it becomes available. - LOCK2 implies LOCK1, and additionally acquires the exclusive hardware lock, blocking all other hardware threads from executing. Signed-off-by: James Hogan <james.hogan@imgtec.com>