Re: [PATCH] ARM: Gemini: Add support for PCI BUS

From: Russell King - ARM Linux
Date: Mon Nov 29 2010 - 14:33:14 EST


On Mon, Nov 29, 2010 at 06:05:07PM +0200, Paulius Zaleckas wrote:
> No he really should NOT use readl/writel. The ONLY difference
> between readl/writel and __raw_readl/__raw_writel is endianess
> conversion. __raw_*l is not doing it. Which to use depend only
> on HW.

Wrong. readl/writel have barriers too to guarantee ordering between
device accesses and memory accesses. (device accesses are already
ordered with respect to themselves.) __raw variants do not
guarantee the relative ordering between memory accesses and device
accesses.
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