All of lore.kernel.org
 help / color / mirror / Atom feed
From: Michael Baumann <baumann@optivus.com>
To: linux-kernel@vger.kernel.org
Subject: Problem trying to implement mmap for device on 2.4
Date: Wed, 6 Oct 2004 09:50:39 -0700	[thread overview]
Message-ID: <200410060950.39483.baumann@optivus.com> (raw)

Sorry if this is too much of a noob question - do point me to the right place
if you can.
System: PPC on VME
Attempting driver for 3rd party NVRAM board - it's meant to be used as
a data-store/system-state recorder. Will be used by more than one
processor in the system - each processor is to use a "chunk" of the RAM
as it's scratch space. Or that's the plan.

Based on what I thought I understood from Rubini&Corbet 2nd Edition
I created a simple module, that provided a mmap method - after reserving
the region via request_mem_region.

mapping was done with a simple remap_page_range() 

In userland, the mmap system call is made, with MAP_FIXED
and the kernel immediately fails the call with "cannot allocate memory" - 
never even getting to my implementation of the mmap call. Apparently
dying somewhere during "the good deal of work" Rubini talks about.
If I don't use MAP_FIXED, things 'work', but I need that fixed location,
I'm obviously trying to map the RAM into user space for access.


I'm assuming I'm missing something simple in the setup, somewhere.
Any help/pointers/ even insults accepted - I'm in a tough spot here.

 
-- 
--
#include <std_disclaimer>
Michael Baumann   9518974841
Optivus Technology, Inc.

             reply	other threads:[~2004-10-06 16:57 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-06 16:50 Michael Baumann [this message]
2004-10-06 17:16 ` Problem trying to implement mmap for device on 2.4 Richard B. Johnson

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=200410060950.39483.baumann@optivus.com \
    --to=baumann@optivus.com \
    --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 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.