From: David Laight <David.Laight@ACULAB.COM>
To: 'Robin Murphy' <robin.murphy@arm.com>,
Hans de Goede <hdegoede@redhat.com>,
Roger Quadros <rogerq@ti.com>,
"axboe@kernel.dk" <axboe@kernel.dk>
Cc: "vigneshr@ti.com" <vigneshr@ti.com>,
"nsekhar@ti.com" <nsekhar@ti.com>,
"linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"Christoph Hellwig" <hch@lst.de>,
"Rob Herring" <robh+dt@kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"Kishon Vijay Abraham I" <kishon@ti.com>,
"Péter Ujfalusi" <peter.ujfalusi@ti.com>
Subject: RE: [PATCH] ata: ahci_platform: add 32-bit quirk for dwc-ahci
Date: Wed, 12 Feb 2020 11:56:06 +0000 [thread overview]
Message-ID: <2a527d21087b4f959c7f95895d70b669@AcuMS.aculab.com> (raw)
In-Reply-To: <7e5f503f-03df-29d0-baae-af12d0af6f61@arm.com>
From: Robin Murphy
> Sent: 12 February 2020 11:43
...
> If the device *is* inherently 64-bit capable, then setting 64-bit masks
> in the driver is correct - if a 64-bit IP block happens to have been
> integrated with only 32 address bits wired up, but the system has memory
> above the 32-bit boundary, then that should be described via
> "dma-ranges", which should then end up being used to further constrain
> the device masks internally to the DMA API.
Given how often this happens (please can I shoot some more
hardware engineers - he says while compiling some VHDL)
is it possible to allocate some memory pages that are
aliases if the address bits over 31 are ignored?
Then (at least some) drivers could to a run-time probe
reading to the high address and checking the data didn't
appear in the low address.
Only one such set of pages is needed - access can be locked.
But they'd need to be reserved early on.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2020-02-12 11:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-06 11:17 [PATCH] ata: ahci_platform: add 32-bit quirk for dwc-ahci Roger Quadros
2020-02-06 11:50 ` Hans de Goede
2020-02-06 11:54 ` Roger Quadros
2020-02-12 11:01 ` Roger Quadros
2020-02-12 11:32 ` Hans de Goede
2020-02-12 11:43 ` Robin Murphy
2020-02-12 11:56 ` David Laight [this message]
2020-02-12 12:09 ` Robin Murphy
2020-02-13 7:24 ` Roger Quadros
Reply instructions:
You may reply publicly 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=2a527d21087b4f959c7f95895d70b669@AcuMS.aculab.com \
--to=david.laight@aculab.com \
--cc=axboe@kernel.dk \
--cc=devicetree@vger.kernel.org \
--cc=hch@lst.de \
--cc=hdegoede@redhat.com \
--cc=kishon@ti.com \
--cc=linux-ide@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nsekhar@ti.com \
--cc=peter.ujfalusi@ti.com \
--cc=robh+dt@kernel.org \
--cc=robin.murphy@arm.com \
--cc=rogerq@ti.com \
--cc=stable@vger.kernel.org \
--cc=vigneshr@ti.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).