From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932355Ab2DFV46 (ORCPT ); Fri, 6 Apr 2012 17:56:58 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:53694 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753887Ab2DFV45 (ORCPT ); Fri, 6 Apr 2012 17:56:57 -0400 Message-ID: <4F7F66A4.8070701@wwwdotorg.org> Date: Fri, 06 Apr 2012 15:56:52 -0600 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.28) Gecko/20120313 Thunderbird/3.1.20 MIME-Version: 1.0 To: "Williams, Dan J" CC: gregkh@linuxfoundation.org, Sudhakar Mamillapalli , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Colin Cross , Olof Johansson , Nhan H Mai , Alan Cox , alan@linux.intel.com Subject: Re: [PATCH 4/6] tegra, serial8250: add ->handle_break() uart_port op References: <20120406184346.21744.18004.stgit@dwillia2-linux.jf.intel.com> <20120406184956.22088.85217.stgit@dwillia2-linux.jf.intel.com> <4F7F59B2.4090400@wwwdotorg.org> In-Reply-To: X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/06/2012 03:28 PM, Williams, Dan J wrote: > On Fri, Apr 6, 2012 at 2:01 PM, Stephen Warren wrote: >> On 04/06/2012 12:49 PM, Dan Williams wrote: >>> The "KT" serial port has another use case for a "received break" quirk, >>> so before adding another special case to the 8250 core take this >>> opportunity to push such quirks out of the core and into a uart_port op. >> >> This doesn't seem quite right. Why do the board files have to set up >> this .handle_break function; they're already setting .type=PORT_TEGRA, >> which should be enough to drive the setup of any required quirks. > > Because struct serial8250_config does not convey any uart_port ops. But couldn't it be enhanced to do so, just like this patch added a field to struct uart_port for this? If you went this route, then the change would be entirely isolated within 8250.c, so you could drop all the arch/arm/mach-tegra changes, and also not need to update of_serial.c. >> I'm not sure what the implication is of moving the call to clr_fifo() >> into uart_handle_break(). What's the benefit of one location over the other? > > This was the location where the core was already doing it's break > handling, so it made sense to check here if the device had any quirks > to run. There shouldn't be any implications because the core was > already doing clear_rx_fifo() immediately before calling > uart_handle_break. Here is the relevant hunk with a bit more context: Ah OK, that part seems fine then.