From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935470AbXGYT3X (ORCPT ); Wed, 25 Jul 2007 15:29:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935831AbXGYT2y (ORCPT ); Wed, 25 Jul 2007 15:28:54 -0400 Received: from gateway-1237.mvista.com ([63.81.120.155]:26013 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S935812AbXGYT2w (ORCPT ); Wed, 25 Jul 2007 15:28:52 -0400 Message-ID: <46A7A4EC.2020503@ru.mvista.com> Date: Wed, 25 Jul 2007 23:30:52 +0400 From: Sergei Shtylyov Organization: MontaVista Software Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; rv:1.7.2) Gecko/20040803 X-Accept-Language: ru, en-us, en-gb MIME-Version: 1.0 To: Scott Wood Cc: Vitaly Bordug , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, segher@kernel.crashing.org Subject: Re: [PATCH 2/2] [POWERPC] MPC8349E-mITX: use platform IDE driver for CF interface References: <20070725165318.5331.23795.stgit@localhost.localdomain> <20070725165326.5331.19920.stgit@localhost.localdomain> <46A78322.3080607@ru.mvista.com> <46A78E3F.1030904@ru.mvista.com> <20070725180145.GA29689@ld0162-tx32.am.freescale.net> <46A7941F.2050300@ru.mvista.com> <46A798D8.7020906@freescale.com> In-Reply-To: <46A798D8.7020906@freescale.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Scott Wood wrote: >> Scott Wood wrote: >>>> Also, what mmio-ide in the compat properly means in the context >>>> of ide_platform which is able to handle both port and memory mapped >>>> IDE. >>> I/O-space is only valid in the context of PCI, ISA, or similar buses, >>> and >>> the bus-specific reg format indicates whether it's mmio-space or >>> io-space. >> You could save time on lecturing me (and use it to look on the >> driver ;-). > Sorry, I misread the question as being a mismatch between the > capabilities of the device binding and the driver, not about the > specific compatible name. That too. :-) > Something like "generic-ide" would probably be better. I strongly disagree with "generic" part. The generic IDE could only be said of 1:1 I/O mapped IDE ports, not about this fancy mapping. >>> What is board specific about a set of standard IDE registers at a given >> The regisrer mapping used is highly non-standard. > The gap between registers is nonstandard, but that's a fairly common > type of noncompliance in embedded-land, and probably merits being That is only a common variation of embedded non-compliancy (which doesn't make it a compliancy. ;-) There are worse cases in the bi-endian land, even with the standard 8-bit regs and 1-byte stride. *Hopefully*, this driver could also support those... > supported in a generic way. I wouldn't call it "highly" nonstandard. Yeah, there are also 8250 "compatible" UARTs that use 32-bit memory accesses, and even worse -- with some registers mapped differently than on 8250 (those can't be called compatible by any means), yet 8250.c drives all of them. I'm not really sure it was such a good idea to merge, say Alchemy UART support into 8250.c. > Is there some other non-standardness that I'm missing? *Hopefully*, none. The original Kumar's driver pretended to handle byte-lane swapping too (but that was ugly :-). >> We're already in board specific code, so why the heck not? :-) >>> various ns16550-compatibles out there as well? >> I never suggested that -- what I did suggest was make of_serial.c >> recognize certain chip types and register them with 8250 driver. > What would be the advantage of maintaining a list of chips whose only Nobody's talking about the advantages, just about the device tree accepted practices (which we've already tried to bypass with MTD node -- causing a lot of bashing until David Woodhouse came to help :-). > difference is register spacing, rather than just using reg-shift and > being done with it? Please read the linuxppc-dev archive's threads following form David's patches. Or maybe Segher could repeat this for you. ;-) > -Scott MBR, Sergei