dmaengine Archive on lore.kernel.org
 help / color / Atom feed
From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: Rob Herring <robh+dt@kernel.org>, Robin Murphy <robin.murphy@arm.com>
Cc: "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
	<linux-arm-kernel@lists.infradead.org>,
	devicetree@vger.kernel.org, Matthias Brugger <mbrugger@suse.com>,
	Frank Rowand <frowand.list@gmail.com>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	etnaviv@lists.freedesktop.org,
	"open list:DMA GENERIC OFFLOAD ENGINE SUBSYSTEM" 
	<dmaengine@vger.kernel.org>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Stefan Wahren <wahrenst@gmx.net>,
	james.quinlan@broadcom.com, linux-pci@vger.kernel.org,
	linux-tegra@vger.kernel.org, xen-devel@lists.xenproject.org,
	Dan Williams <dan.j.williams@intel.com>,
	freedreno <freedreno@lists.freedesktop.org>,
	Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [PATCH 00/11] of: Fix DMA configuration for non-DT masters
Date: Thu, 26 Sep 2019 12:44:53 +0200
Message-ID: <307b988d0c67fb1c42166eca12742bcfda09d92d.camel@suse.de> (raw)
In-Reply-To: <CAL_JsqKKYcHPnA80ZwLY=Sk3e5MqrimedUhWQ5+iuPZXQxYHdA@mail.gmail.com>

[-- Attachment #1: Type: text/plain, Size: 1872 bytes --]

> > > > Robin, have you looked into supporting multiple dma-ranges? It's the
> > > > next thing
> > > > we need for BCM STB's PCIe. I'll have a go at it myself if nothing is in
> > > > the
> > > > works already.
> > > 
> > > Multiple dma-ranges as far as configuring inbound windows should work
> > > already other than the bug when there's any parent translation. But if
> > > you mean supporting multiple DMA offsets and masks per device in the
> > > DMA API, there's nothing in the works yet.

Sorry, I meant supporting multiple DMA offsets[1]. I think I could still make
it with a single DMA mask though.

> > There's also the in-between step of making of_dma_get_range() return a
> > size based on all the dma-ranges entries rather than only the first one
> > - otherwise, something like [1] can lead to pretty unworkable default
> > masks. We implemented that when doing acpi_dma_get_range(), it's just
> > that the OF counterpart never caught up.
> 
> Right. I suppose we assume any holes in the ranges are addressable by
> the device but won't get used for other reasons (such as no memory
> there). However, to be correct, the range of the dma offset plus mask
> would need to be within the min start and max end addresses. IOW,
> while we need to round up (0xa_8000_0000 - 0x2c1c_0000) to the next
> power of 2, the 'correct' thing to do is round down.

IIUC I also have this issue on my list. The RPi4 PCIe block has an integration
bug that only allows DMA to the lower 3GB. With dma-ranges of size 0xc000_0000
you get a 32bit DMA mask wich is not what you need. So far I faked it in the
device-tree but I guess it be better to add an extra check in
of_dma_configure(), decrease the mask and print some kind of warning stating
that DMA addressing is suboptimal.

Regards,
Nicolas

[1] https://lkml.org/lkml/2018/9/19/641


[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-24 18:12 Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 01/11] of: address: clean-up unused variable in of_dma_get_range() Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 02/11] of: base: introduce __of_n_*_cells_parent() Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 03/11] of: address: use parent DT node in bus->count_cells() Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 04/11] of: address: introduce of_translate_dma_address_parent() Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 05/11] of: expose __of_get_dma_parent() to OF subsystem Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 06/11] of: address: use parent OF node in of_dma_get_range() Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 07/11] dts: arm64: layerscape: add dma-ranges property to qoric-mc node Nicolas Saenz Julienne
2019-10-14  8:28   ` Shawn Guo
2019-10-14 10:00     ` Nicolas Saenz Julienne
2019-10-14 11:09       ` Shawn Guo
2019-09-24 18:12 ` [PATCH 08/11] dts: arm64: layerscape: add dma-ranges property to pcie nodes Nicolas Saenz Julienne
2019-10-14  8:29   ` Shawn Guo
2019-09-24 18:12 ` [PATCH 09/11] of: device: remove comment in of_dma_configure() Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 10/11] of: device: introduce of_dma_configure_parent() Nicolas Saenz Julienne
2019-09-24 18:12 ` [PATCH 11/11] of: simplify of_dma_config()'s arguments Nicolas Saenz Julienne
2019-09-24 21:59 ` [PATCH 00/11] of: Fix DMA configuration for non-DT masters Rob Herring
2019-09-25 14:52   ` Nicolas Saenz Julienne
2019-09-25 15:09     ` Robin Murphy
2019-09-25 15:30       ` Nicolas Saenz Julienne
2019-09-25 16:16         ` Rob Herring
2019-09-25 16:52           ` Robin Murphy
2019-09-25 21:33             ` Rob Herring
2019-09-26 10:44               ` Nicolas Saenz Julienne [this message]
2019-09-26 11:20                 ` Robin Murphy
2019-10-02 18:28                   ` Florian Fainelli
2019-09-25 16:07     ` Rob Herring

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=307b988d0c67fb1c42166eca12742bcfda09d92d.camel@suse.de \
    --to=nsaenzjulienne@suse.de \
    --cc=dan.j.williams@intel.com \
    --cc=devicetree@vger.kernel.org \
    --cc=dmaengine@vger.kernel.org \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=etnaviv@lists.freedesktop.org \
    --cc=f.fainelli@gmail.com \
    --cc=freedreno@lists.freedesktop.org \
    --cc=frowand.list@gmail.com \
    --cc=james.quinlan@broadcom.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=mbrugger@suse.com \
    --cc=robh+dt@kernel.org \
    --cc=robin.murphy@arm.com \
    --cc=wahrenst@gmx.net \
    --cc=xen-devel@lists.xenproject.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

dmaengine Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/dmaengine/0 dmaengine/git/0.git

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

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.dmaengine


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