From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750895AbXBKVgM (ORCPT ); Sun, 11 Feb 2007 16:36:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750897AbXBKVgM (ORCPT ); Sun, 11 Feb 2007 16:36:12 -0500 Received: from gate.crashing.org ([63.228.1.57]:52538 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750884AbXBKVgL (ORCPT ); Sun, 11 Feb 2007 16:36:11 -0500 Subject: Re: remote debugging via FireWire From: Benjamin Herrenschmidt To: Stefan Richter Cc: Andi Kleen , Bernhard Kaindl , discuss@x86-64.org, linux1394-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org In-Reply-To: <45CE19F3.2070603@s5r6.in-berlin.de> References: <200702101242.48467.ak@suse.de> <200702101502.59431.ak@suse.de> <45CDE14C.4040203@s5r6.in-berlin.de> <200702101641.36239.ak@suse.de> <45CE19F3.2070603@s5r6.in-berlin.de> Content-Type: text/plain Date: Mon, 12 Feb 2007 08:35:38 +1100 Message-Id: <1171229738.20494.60.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2007-02-10 at 20:16 +0100, Stefan Richter wrote: > [ohci1394_early] > > Some remarks to the September 2006 version at > http://www.suse.de/~bk/firewire/ : > > - Seems its .remove won't work properly if more than one OHCI-1394 > controller is installed. And it's .probe isn't reentrant, but that > might be less of a problem. > - Its functionality will be lost if there is a FireWire bus reset, > e.g. when something is plugged in or out. To keep physical DMA > alive, an interrupt handler had to be installed which writes ~0 > to OHCI1394_PhyReqFilter{Hi,Lo}Set. Can interrupt handlers be > registered in an early setup stage? > - There might be some register accesses in the setup which could be > omitted; I'd have to look this up. > - Could be optimized to not use ohci1394.h::struct ti_ohci. > - PCI_CLASS_FIREWIRE_OHCI can be replaced by > include/linux/pci_ids.h::PCI_CLASS_SERIAL_FIREWIRE_OHCI which > was newly added in 2.6.20-git#. > - I suppose .probe should check for PCI_CLASS_SERIAL_FIREWIRE_OHCI > instead of PCI_CLASS_SERIAL_FIREWIRE. > - How about dropping support for configuring this as module, to > simplify the code? Unless this would interfere with ohci1394; and > it probably would if there was an interrupt handler... > - "depends on X86_64" is missing in Kconfig. > - Maybe put it into arch/x86_64/drivers/ instead of drivers/ieee1394? > - Plus what I mentioned earlier in the thread. > > I could send code to address some of this at next weekend or later. I'd like to have that on ppc as well, so I'd rather keep it in drivers/ I agree that it doesn't need to be a module. If you can load modules, then you can load the full ohci driver. Thus, if it's an early thingy initialized by arch, it can export a special "takeover" hook that the proper ohci module can then call to override it (important if we start having an irq handler). Andi, also, how do you deal with iommu ? Not at all ? :-) Ben.