From: "H. Peter Anvin" <hpa@zytor.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: josh@joshtriplett.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org
Subject: Re: [PATCH] drivers/char/mem.c: Add /dev/ioports, supporting 16-bit and 32-bit ports
Date: Thu, 29 May 2014 06:38:35 -0700 [thread overview]
Message-ID: <5387385B.1030203@zytor.com> (raw)
In-Reply-To: <16228376.RHijyT1ZPk@wuerfel>
On 05/29/2014 02:26 AM, Arnd Bergmann wrote:
> On Wednesday 28 May 2014 14:41:52 H. Peter Anvin wrote:
>> On 05/19/2014 05:36 AM, Arnd Bergmann wrote:
>>>
>>> My feeling is that all devices we can think of fall into at least one
>>> of these categories:
>>>
>>> * legacy PC stuff that needs only byte access
>>> * PCI devices that can be accessed through sysfs
>>> * devices on x86 that can be accessed using iopl
>>>
>>
>> I don't believe PCI I/O space devices can be accessed through sysfs, but
>> perhaps I'm wrong? (mmapping I/O space is not portable.)
>
> The interface is there, both a read/write and mmap on the resource
> bin_attribute. But it seems you're right, neither of them is implemented
> on all architectures.
>
> Only powerpc, microblaze, alpha, sparc and xtensa allow users to mmap
> I/O space, even though a lot of others could. The read-write interface
> is only defined for alpha, ia64, microblaze and powerpc.
>
And how is that read/write interface defined? Does it have the same
silly handling of data sizes?
-hpa
next prev parent reply other threads:[~2014-05-29 13:39 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-09 19:19 [PATCH] drivers/char/mem.c: Add /dev/ioports, supporting 16-bit and 32-bit ports Josh Triplett
2014-05-09 19:21 ` [PATCH] mem.4, ioports.4: Document /dev/ioports Josh Triplett
2014-05-13 8:27 ` Michael Kerrisk (man-pages)
2014-05-09 19:58 ` [PATCH] drivers/char/mem.c: Add /dev/ioports, supporting 16-bit and 32-bit ports Arnd Bergmann
2014-05-09 20:54 ` H. Peter Anvin
2014-05-09 21:12 ` Arnd Bergmann
2014-05-09 21:20 ` H. Peter Anvin
2014-05-09 22:38 ` Josh Triplett
2014-05-13 22:10 ` H. Peter Anvin
2014-05-15 21:56 ` josh
2014-05-19 12:36 ` Arnd Bergmann
2014-05-28 21:41 ` H. Peter Anvin
2014-05-29 9:26 ` Arnd Bergmann
2014-05-29 13:38 ` H. Peter Anvin [this message]
2014-05-30 11:32 ` Arnd Bergmann
2015-12-22 10:52 ` Santosh Shukla
2015-12-22 21:56 ` Arnd Bergmann
2015-12-22 22:02 ` H. Peter Anvin
2015-12-22 22:11 ` Arnd Bergmann
2015-12-23 11:34 ` Santosh Shukla
2015-12-29 13:28 ` Arnd Bergmann
2015-12-29 15:53 ` Santosh Shukla
2015-12-29 15:55 ` Santosh Shukla
2015-12-29 16:20 ` Arnd Bergmann
2015-12-29 16:30 ` Santosh Shukla
2015-12-29 17:31 ` Alex Williamson
2015-12-31 9:33 ` Santosh Shukla
2015-12-31 15:41 ` Alex Williamson
2016-01-07 9:31 ` Santosh Shukla
2014-05-10 7:07 ` Jann Horn
2014-05-10 19:32 ` Josh Triplett
2014-05-11 12:50 ` Jann Horn
2014-05-11 21:05 ` Josh Triplett
2014-06-01 10:35 ` Maciej W. Rozycki
2014-06-04 22:59 ` H. Peter Anvin
2014-06-06 9:02 ` Maciej W. Rozycki
2014-05-10 17:18 ` Greg Kroah-Hartman
2014-05-10 19:36 ` Josh Triplett
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=5387385B.1030203@zytor.com \
--to=hpa@zytor.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=gregkh@linuxfoundation.org \
--cc=josh@joshtriplett.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.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
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).