Re: [RFT PATCH v3 12/27] of/address: Add infrastructure to declare MMIO as non-posted
From: Rob Herring <robh@kernel.org>
Date: 2021-03-09 15:49:11
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On Mon, Mar 8, 2021 at 2:56 PM Arnd Bergmann [off-list ref] wrote:
On Mon, Mar 8, 2021 at 10:14 PM Rob Herring [off-list ref] wrote:quoted
On Mon, Mar 08, 2021 at 09:29:54PM +0100, Arnd Bergmann wrote:quoted
On Mon, Mar 8, 2021 at 4:56 PM Rob Herring [off-list ref] wrote:Let's just stick with 'nonposted-mmio', but drop 'posted-mmio'. I'd rather know if and when we need 'posted-mmio'. It does need to be added to the DT spec[1] and schema[2] though (GH PRs are fine for both).I think the reason for having "posted-mmio" is that you cannot properly define the PCI host controller nodes on the M1 without that: Since nonposted-mmio applies to all child nodes, this would mean the PCI memory space gets declared as nonposted by the DT, but the hardware requires it to be mapped as posted.
I don't think so. PCI devices wouldn't use any of the code paths in this patch. They would map their memory space with plain ioremap() which is posted. Rob _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel