Aw: Re: RFC on writel and writel_relaxed

Lino Sanfilippo LinoSanfilippo at
Wed Mar 28 21:13:22 AEDT 2018


> Yeah so that other trick I'm talking about is also used for timing
> accuracy.
> For example, let's say I have a device with a reset bit and the spec
> says the reset bit needs to be set for at least 10us.
> This is wrong:
> 	writel(1, RESET_REG);
> 	usleep(10);
> 	writel(0, RESET_REG);
> Because of write posting, the first write might arrive to the device
> right before the second one.

Does not write posting only concern PCI? This seems to be a different topic. Furthermore
write posting should not include write reordering...


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