From: Christoph Hellwig <hch@lst.de>
To: Paul Burton <paul.burton@mips.com>
Cc: Shawn Anastasio <shawn@anastas.io>, Will Deacon <will@kernel.org>,
"linux-m68k@lists.linux-m68k.org"
<linux-m68k@lists.linux-m68k.org>,
Catalin Marinas <catalin.marinas@arm.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Russell King <linux@armlinux.org.uk>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
James Hogan <jhogan@kernel.org>, Guan Xuetao <gxt@pku.edu.cn>,
Christoph Hellwig <hch@lst.de>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: cleanup the dma_pgprot handling
Date: Sun, 25 Aug 2019 00:34:49 +0200 [thread overview]
Message-ID: <20190824223449.GC21729@lst.de> (raw)
In-Reply-To: <20190823215759.zprrwotlbva46y33@pburton-laptop>
On Fri, Aug 23, 2019 at 09:58:04PM +0000, Paul Burton wrote:
> So I believe uncached & uncached accelerated are another case like that
> described above - they're 2 different CCAs but the same "access type",
> namely uncached.
>
> Section 4.9 then goes on to forbid mixing access types, but not CCAs.
>
> It would be nice if the precise mapping from CCA to access type was
> provided, but I don't see that anywhere. I can check with the
> architecture team to be sure, but to my knowledge we're fine to mix
> access via kseg1 (ie. uncached) & mappings with CCA=7 (uncached
> accelerated).
Ok. Looks like we can keep it then and I'll add a comment to the
code with the above reference.
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prev parent reply other threads:[~2019-08-24 22:35 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-16 7:07 cleanup the dma_pgprot handling Christoph Hellwig
2019-08-16 7:07 ` [PATCH 1/6] MIPS: remove support for DMA_ATTR_WRITE_COMBINE Christoph Hellwig
2019-08-16 7:07 ` [PATCH 2/6] unicore32: remove the unused pgprot_dmacoherent define Christoph Hellwig
2019-08-16 7:07 ` [PATCH 3/6] arm-nommu: " Christoph Hellwig
2019-08-16 7:07 ` [PATCH 4/6] dma-mapping: remove arch_dma_mmap_pgprot Christoph Hellwig
2019-08-16 7:43 ` Geert Uytterhoeven
2019-08-16 7:07 ` [PATCH 5/6] dma-mapping: make dma_atomic_pool_init self-contained Christoph Hellwig
2019-08-16 7:07 ` [PATCH 6/6] arm64: document the choice of page attributes for pgprot_dmacoherent Christoph Hellwig
2019-08-16 17:31 ` Will Deacon
2019-08-16 17:36 ` Mark Rutland
2019-08-16 17:59 ` Christoph Hellwig
2019-08-16 18:05 ` Will Deacon
2019-08-23 21:58 ` cleanup the dma_pgprot handling Paul Burton
2019-08-24 22:34 ` Christoph Hellwig [this message]
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