From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752811Ab1KAI6f (ORCPT ); Tue, 1 Nov 2011 04:58:35 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:50051 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752535Ab1KAI6e (ORCPT ); Tue, 1 Nov 2011 04:58:34 -0400 Message-ID: <4EAFB34D.8080807@gmail.com> Date: Tue, 01 Nov 2011 09:52:29 +0100 From: Marco Stornelli User-Agent: Mozilla/5.0 (X11; U; Linux i686; it; rv:1.9.2.23) Gecko/20110920 SUSE/3.1.15 Thunderbird/3.1.15 MIME-Version: 1.0 To: Bryan Freed CC: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, msb@chromium.org, seiji.aguchi@hds.com Subject: Re: [PATCH] ramoops appears geared to not support ARM References: <1319844110-23062-1-git-send-email-bfreed@chromium.org> <4EAC0C18.5090602@gmail.com> <4EAD360D.6010004@gmail.com> <4EAE630A.6040309@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 01/11/2011 00:03, Bryan Freed ha scritto: > On Mon, Oct 31, 2011 at 1:57 AM, Marco Stornelli >>> And I cannot shake the feeling that we have a fairly simple disconnect >>> here. Ramoops expects to use _device_ memory because it uses >>> ioremap(). But the buffer itself is accessed through /dev/mem which >>> (as we use it with no mmap() calls) expects to give access to _system_ >> >> no mmap calls?! I don't understand how you are using /dev/mem. > > open(), lseek(), read(). No mmap is required for RAM, right? > dd if=/dev/mem bs=1 count=1000 skip=32M > Mmmm, the operations done are different. Try: reserve the memory with memblock_reserve and read some data with this useful program http://free-electrons.com/pub/mirror/devmem2.c from the right location (the address used for ramoops). Let me know. Marco