Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / Atom feed
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
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.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

      reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16  7:07 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]

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190824223449.GC21729@lst.de \
    --to=hch@lst.de \
    --cc=catalin.marinas@arm.com \
    --cc=geert@linux-m68k.org \
    --cc=gxt@pku.edu.cn \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jhogan@kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-m68k@lists.linux-m68k.org \
    --cc=linux-mips@vger.kernel.org \
    --cc=linux@armlinux.org.uk \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=paul.burton@mips.com \
    --cc=robin.murphy@arm.com \
    --cc=shawn@anastas.io \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-ARM-Kernel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/0 linux-arm-kernel/git/0.git
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/1 linux-arm-kernel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-kernel linux-arm-kernel/ https://lore.kernel.org/linux-arm-kernel \
		linux-arm-kernel@lists.infradead.org infradead-linux-arm-kernel@archiver.kernel.org
	public-inbox-index linux-arm-kernel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-arm-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox