On Friday 10 March 2006 00:34, you wrote: > David Howells writes: > > > +On some systems, I/O writes are not strongly ordered across all CPUs, and > > so > > +locking should be used, and mmiowb() should be issued prior to unlocking > > the > > +critical section. > > I think we should say more strongly that mmiowb() is required where > MMIO accesses are done under a spinlock, and that if your driver is > missing them then that is a bug. I don't think it makes sense to say > that mmiowb is required "on some systems".
So what about:
#define spin_lock_mmio(lock) spin_lock(lock)
#define spin_unlock_mmio(lock) do { spin_unlock(lock); mmiowb(); } while (0)
#define spin_lock_mmio_irqsave(lock, flags) spin_lock_irqsave(lock, flags)
#define spin_unlock_mmio_irqrestore(lock, flags) do {
spin_unlock_irqrestore(lock, flags); mmiowb(); } while (0)
--
Greetings Michael.
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