Re: [PATCHv4 1/6] iommu/io-pgtable-arm: Add support to use system cache

From: Robin Murphy
Date: Mon Sep 21 2020 - 18:03:53 EST


On 2020-09-21 19:03, Will Deacon wrote:
On Fri, Sep 11, 2020 at 07:57:18PM +0530, Sai Prakash Ranjan wrote:
Add a quirk IO_PGTABLE_QUIRK_SYS_CACHE to override the
attributes set in TCR for the page table walker when
using system cache.

I wonder if the panfrost folks can reuse this for the issue discussed
over at:

https://lore.kernel.org/r/cover.1600213517.git.robin.murphy@xxxxxxx

Isn't this all hinged around the outer cacheability attribute, rather than shareability (since these are nominally NC mappings and thus already properly Osh)? The Panfrost issue is just about shareability domains being a bit wonky; the cacheability attributes there are actually reasonably normal (other than not having a non-cacheable type at all, only a choice of allocation policies...)

Robin.

However, Sai, your email setup went wrong when you posted this so you
probably need to repost now that you have that fixed.

Will
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