Re: HELP: Is writeq an atomic operation??

[Roland Dreier]

 > Yeah,  I forgot I have a #ifndef writeq, then defined the x86_64 version
 > of that.   I've not tested on x86, so I'm not sure whether it works.
 > How are you handling writeq when its not defined, as the case in x86?

Write two writel() inside a spinlock to avoid any transactions in the
middle (the HW I'm dealing with can deal with two 32-bit transactions,
as long as nothing comes in the middle).  If your hardware demands a
single 64-bit transaction, you may be in trouble, because I'm not sure
all 32-bit systems can generate such a PCIe transaction.

You can see include/linux/mlx4/doorbell.h for exactly what I did.

 - R.
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