From: Matt Porter <mporter@kernel.crashing.org>
To: Ralph Siemsen <rsiemsen@rossvideo.com>
Cc: ppcembed <linuxppc-embedded@ozlabs.org>
Subject: Re: 2.6 4xx GPIO OCP driver?
Date: Fri, 25 Feb 2005 17:29:41 -0700 [thread overview]
Message-ID: <20050225172941.A30499@cox.net> (raw)
In-Reply-To: <421F966D.4060206@rossvideo.com>; from rsiemsen@rossvideo.com on Fri, Feb 25, 2005 at 04:19:41PM -0500
On Fri, Feb 25, 2005 at 04:19:41PM -0500, Ralph Siemsen wrote:
> Matt Porter wrote:
>
> > I didn't bother merging it upstream at one time. It wasn't clear
> > if the driver had any value over just mmaping /dev/mem to bang
> > on the couple gpio registers directly. [...]
>
> Will that work on the 440 where the devices sit above 4GB mark? Or must
> one rely on there being an existing TLB mapping to bring them into
> 32-bit space?
Ack...that's the one thing we are missing. :-/ I had forgotten
that driver/char/mem.c calls remap_pfn_range() directly rather
than io_remap_page_range(). Had it called the latter, we'd be OK
since the "bigphys" fixup could take place. We can fix /dev/mem to
call io_remap_page_range() when on ppc32 && 36-bit phys...other arches
do similar tricks in that driver.
If everybody is happy with mmaping /dev/mem then we can go try that
route.
-Matt
next prev parent reply other threads:[~2005-02-26 0:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-25 19:40 2.6 4xx GPIO OCP driver? Steven Blakeslee
2005-02-25 20:25 ` Travis B. Sawyer
2005-02-25 20:30 ` Matt Porter
2005-02-25 20:51 ` Travis B. Sawyer
2005-02-25 21:19 ` Ralph Siemsen
2005-02-26 0:29 ` Matt Porter [this message]
2005-02-26 22:31 ` Travis Sawyer
2005-02-26 22:31 ` Travis B. Sawyer
-- strict thread matches above, loose matches on Subject: below --
2005-02-25 17:17 Travis B. Sawyer
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=20050225172941.A30499@cox.net \
--to=mporter@kernel.crashing.org \
--cc=linuxppc-embedded@ozlabs.org \
--cc=rsiemsen@rossvideo.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.