Re: [PATCH 05/20] ARM: implement pci_remap_cfgspace() interface

From	Russell King - ARM Linux <linux@armlinux.org.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH 05/20] ARM: implement pci_remap_cfgspace() interface
Date	2017-03-21 18:00 +0100
Message-ID	<tnviy-5Yp-17@gated-at.bofh.it> (permalink)
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On Tue, Mar 21, 2017 at 03:26:36PM +0000, Lorenzo Pieralisi wrote:
> I assumed that in plain terms, the difference between MT_DEVICE and
> MT_UNCACHED is write posting (aka bufferable) behaviour (across CPU
> architecture versions) and that does not affect write ordering rules.

Having looked it up in the ARM ARM, I think we're fine.  Device and
strongly ordered accesses are both ordered as one group, so can be
thought of as the same.  The only difference is that Device can
complete from the CPU's perspective before it hits the peripheral,
whereas strongly ordered only completes once it's hit the peripheral.

So this looks like exactly the right thing to do here.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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Re: [PATCH 05/20] ARM: implement pci_remap_cfgspace() interface Russell King - ARM Linux <linux@armlinux.org.uk> - 2017-03-20 18:00 +0100
  Re: [PATCH 05/20] ARM: implement pci_remap_cfgspace() interface Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2017-03-21 16:30 +0100
    Re: [PATCH 05/20] ARM: implement pci_remap_cfgspace() interface Russell King - ARM Linux <linux@armlinux.org.uk> - 2017-03-21 18:00 +0100

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