From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754955Ab1J2JfU (ORCPT ); Sat, 29 Oct 2011 05:35:20 -0400 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:35678 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754095Ab1J2JfT (ORCPT ); Sat, 29 Oct 2011 05:35:19 -0400 Date: Sat, 29 Oct 2011 10:34:58 +0100 From: Russell King - ARM Linux To: Marco Stornelli Cc: linux-arm-kernel@lists.infradead.org, msb@chromium.org, linux-kernel@vger.kernel.org, sergiu@chromium.org, Bryan Freed , akpm@linux-foundation.org, seiji.aguchi@hds.com Subject: Re: [PATCH] ramoops appears geared to not support ARM Message-ID: <20111029093458.GX19187@n2100.arm.linux.org.uk> References: <1319844110-23062-1-git-send-email-bfreed@chromium.org> <4EABBBD3.5030700@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4EABBBD3.5030700@gmail.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 29, 2011 at 10:39:47AM +0200, Marco Stornelli wrote: > (Added linux-arm) > > Il 29/10/2011 01:21, Bryan Freed ha scritto: >> I had some difficulty in getting ramoops to work on our ARM systems. >> The driver maps memory with ioremap() which is supposed to map IO memory, >> not physical RAM. This happens to work on x86 and apparently some other >> architectures, but it does not work on ARM. >> Specifically, I see this comment in __arm_ioremap_pfn_caller(): >> Don't allow RAM to be mapped - this causes problems with ARMv6+ >> >> So here is a patch that hacks around the issue using page_is_ram() to >> differentiate between the two. >> >> Am I missing something here? >> Is ramoops working on any ARM systems yet, and I am just doing something wrong? >> >> My ARM platform reserves a section of RAM for use by ramoops, but it is still >> mapped along with the rest of main memory. This is so /dev/mem can find it >> with xlate_dev_mem_ptr(). >> On x86, I see our BIOS reserves the memory so that it is not counted as main >> memory, and it is not mapped until ramoops ioremaps it. >> >> Bryan Freed (1): >> ramoops: Add support for ARM systems. >> >> drivers/char/ramoops.c | 67 +++++++++++++++++++++++++++++++++++++---------- >> 1 files changed, 52 insertions(+), 15 deletions(-) >> > > Can some ARM guys give an opinion about that? Opinion about the patch which isn't present in this email (so we can't see it) or about the commentry above?