From patchwork Tue Jul 11 10:37:15 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rob Landley X-Patchwork-Id: 9834393 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 666FD60363 for ; Tue, 11 Jul 2017 10:37:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3E67D26E4A for ; Tue, 11 Jul 2017 10:37:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 328CE283FD; Tue, 11 Jul 2017 10:37:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 57ED2283F9 for ; Tue, 11 Jul 2017 10:37:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755734AbdGKKhY (ORCPT ); Tue, 11 Jul 2017 06:37:24 -0400 Received: from mail-it0-f67.google.com ([209.85.214.67]:36071 "EHLO mail-it0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755673AbdGKKhT (ORCPT ); Tue, 11 Jul 2017 06:37:19 -0400 Received: by mail-it0-f67.google.com with SMTP id k3so2385065ita.3 for ; Tue, 11 Jul 2017 03:37:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=landley-net.20150623.gappssmtp.com; s=20150623; h=subject:to:references:cc:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding; bh=QWaA6eh5SYeLbPFZzO36L5TRMh9dcvm7dx5ArMBqHRE=; b=bIlm0h37s1+SbJUobE1xRhHfKuHGqRMASl7zpR2+H3x+bE/28Ed9RS98d9d8S+oyAu c41fwu5guog4gh8RCNi2w/UKtGIUELcwZ1Uw2iN0M27+pFtszcAE3fgQIS1knjkc1yxs fh0jM9kpmnhQbm+Q56bBh6emGRjvh5rHnM1axPNDBLcx0doLuwqI+yJjq9am8pKIcb5V QlxRnm5HpNeCFoiw0gYs3qrGn0mQyXyD1BmoRdVM/5cT9iP4unZhNIijhHmxsMe0BsnF TrQCdxhm/UFQPUDcfC7VCMZda3yuitlHQZoeqlNTeVWwfmhbij25bXu+8tdvzDPSMBnC fbCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=QWaA6eh5SYeLbPFZzO36L5TRMh9dcvm7dx5ArMBqHRE=; b=oUGPRWRnP1tOJDrf/rqUbyuWdATZQRVqdETMhZDxSFhK047f8AUV89pGC8BgPtO6cB 8C3LGylNVtZr1UPmWPC1fbCfiJKXy+1ihrbE1kE2PaoBb5WaxXZH0d3rxPVZTpjiPnyi pmK4keWlOl+Y3ovTc7K0qWtUL83LpYMjOux9tMaiC2lbwoHTCvjGVVurrgOtDQXCwO88 3qhAWRk5Cu5y7fbwvjvXeqok1RnXV9TyoUBOPqdFJ/DQ13wKFXcde9haEnqvhwDC9QcY iiS5XevDOdO3pGMpF23NM5ZhDLVInxs/l6TnKgjNo3aE79my3UHqCtZQ4cNHzD25K47G qH4A== X-Gm-Message-State: AIVw1121RvS91EeBWfkvLsvyisDfj69WVJj9UztFjx9XNpJ1g81biFe8 e/gc2WI280nfbD/I X-Received: by 10.36.208.139 with SMTP id m133mr2682531itg.48.1499769438700; Tue, 11 Jul 2017 03:37:18 -0700 (PDT) Received: from [192.168.43.158] ([172.58.102.131]) by smtp.googlemail.com with ESMTPSA id q133sm6035384ioe.58.2017.07.11.03.37.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 Jul 2017 03:37:18 -0700 (PDT) Subject: Re: [PATCH 9/9] ARM: multi_v7_defconfig: Enable DMA for Renesas serial ports To: Geert Uytterhoeven , Arnd Bergmann References: <1499693302-25120-1-git-send-email-geert+renesas@glider.be> <1499693302-25120-10-git-send-email-geert+renesas@glider.be> Cc: Magnus Damm , Geert Uytterhoeven , Kevin Hilman , Olof Johansson , Simon Horman , Laurent Pinchart , "linux-arm-kernel@lists.infradead.org" , Linux-Renesas , Yoshinori Sato , Rich Felker , Linux-sh list , "moderated list:H8/300 ARCHITECTURE" From: Rob Landley Message-ID: <95cf2c11-c7db-bdff-7165-282586e08b19@landley.net> Date: Tue, 11 Jul 2017 05:37:15 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On 07/11/2017 03:59 AM, Geert Uytterhoeven wrote: > Hi Arnd, > > On Tue, Jul 11, 2017 at 10:42 AM, Arnd Bergmann wrote: >> On Tue, Jul 11, 2017 at 8:59 AM, Geert Uytterhoeven >> wrote: >>> On Tue, Jul 11, 2017 at 5:38 AM, Magnus Damm wrote: >>>> On Mon, Jul 10, 2017 at 10:28 PM, Geert Uytterhoeven >>>> Since enabling DMA Engine still keeps PIO support around I wonder why >>>> we need this Kconfig at all - other drivers seem to get by without >>>> this kind of thing? >>>> So in my opinion it would also be nice to get rid of SERIAL_SH_SCI_DMA >>>> completely and reducing the number of special per-driver Kconfig >>>> entries. >>> >>> In general, I would agree, and remove the option at the blimp of an eye. >>> However, this driver is shared with H8/300 and SuperH. While both could use >>> DMA (but it's not supported by Linux yet), I don't know if they are willing to >>> live with the increased static and dynamic memory footprint of SH_SCI DMA >>> support. >> >> One more thing: enabling the DMA support in the console driver generally >> means you cannot use printk in the DMA driver anywhere that may be called >> during printk(). Not sure if that is a concern here. > > Not anymore, as all of these prints should have been removed/disabled already. Last I checked qemu-system-sh4 still doesn't work with current linux serial driver unless you do: Does this DMA stuff make that situation worse? Rob --- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -2193,7 +2193,7 @@ static void sci_reset(struct uart_port *port) setup_timer(&s->rx_fifo_timer, rx_fifo_timer_fn, (unsigned long)s); } else { - if (port->type == PORT_SCIFA || + if (1 || port->type == PORT_SCIFA || port->type == PORT_SCIFB) scif_set_rtrg(port, 1); else