Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751586AbWIMF4T (ORCPT ); Wed, 13 Sep 2006 01:56:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751588AbWIMF4T (ORCPT ); Wed, 13 Sep 2006 01:56:19 -0400 Received: from europa.telenet-ops.be ([195.130.137.75]:11208 "EHLO europa.telenet-ops.be") by vger.kernel.org with ESMTP id S1751585AbWIMF4S (ORCPT ); Wed, 13 Sep 2006 01:56:18 -0400 From: Peter Korsgaard To: Olof Johansson Cc: rmk+serial@arm.linux.org.uk, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] Xilinx uartlite serial driver References: <87ac9o3ak3.fsf@sleipner.barco.com> <878xlgercm.fsf@slug.be.48ers.dk> <20060912093301.77f75bfb@localhost.localdomain> Date: Wed, 13 Sep 2006 07:56:03 +0200 In-Reply-To: <20060912093301.77f75bfb@localhost.localdomain> (Olof Johansson's message of "Tue, 12 Sep 2006 09:33:01 -0500") Message-ID: <87ejugxqbw.fsf@slug.be.48ers.dk> User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2380 Lines: 48 >>>>> "Olof" == Olof Johansson writes: Hi Olof, thanks for looking into the driver.. Olof> In my opinion there's a few pieces missing: Olof> 1. There's no early boot console support for PPC. There's another Olof> uartlite patch that's floating around that has this, very useful for Olof> early bringup tasks. I'd like to see this expanded to include that as Olof> well (the regular part of the other driver seems more or less broken Olof> though, so this is a better base driver). That shouldn't stop this part Olof> of the driver to go in though, just possible future work. True. The board I have an uartlite on also has a 8250 so it hasn't been an issue for me so far - But it would indeed be a nice addition. Adding new stuff to arch/ppc at this moment isn't that sensible, so perhaps it makes most sense to wait til 4xx is supported under arch/powerpc? Olof> 2. There seems to be some timeout issues with tx_empty. If I boot a Olof> regular distro with getty, etc, I get veeeery slow console output right Olof> when init starts up. Adding a small default timeout in the init of the Olof> uart code seems to help -- the hanging thread seems to be sleeping in Olof> uart_wait_until_sent(). I picked a value of '5', seems ok. (Also, Olof> without this fix, getty won't start on the port for some reason, it Olof> sits in the same timeout forever, or at least for a very long time). Huh, that's odd - I haven't noticed that. I'll test it again and get back to you. Olof> 3. It would be useful to demonstrate how to hook up the device all the Olof> way through to the board port (i.e. add a config option and include it Olof> in the ml403 platform code or similar). It's not hard, but it'd make it Olof> easier for whomever comes next. Of course, with 4xx hopefully soon Olof> moving over to arch/powerpc, this would be taken care of through the Olof> device tree instead. Yes - Afaik none of the Xilinx boards comes with uartlites configured so it's not usable out-of-the-box, but you can ofcause do a setup with the proper #ifdefs like the 8250 stuff in virtex.c. -- Bye, Peter Korsgaard - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/