From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6CEBC47404 for ; Wed, 9 Oct 2019 19:27:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CB63206B6 for ; Wed, 9 Oct 2019 19:27:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aOz5T6yJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732175AbfJIT1b (ORCPT ); Wed, 9 Oct 2019 15:27:31 -0400 Received: from mail-io1-f67.google.com ([209.85.166.67]:35014 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730708AbfJIT1b (ORCPT ); Wed, 9 Oct 2019 15:27:31 -0400 Received: by mail-io1-f67.google.com with SMTP id q10so7781744iop.2; Wed, 09 Oct 2019 12:27:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=sBG3bzNJ4nIDX1Rgox6bQv5BCuW6Vs82TNv6y6/aj9o=; b=aOz5T6yJ2dx21E8QGDElj5FfpAJrRldZgmrQPrZiwGvDKUsCeBOSCGozlpvql2ibpy H6FcunpnT58lfeD1b4RfHL93Zsqzkvj2+6dNbhZkAXvSoSXog7HvEgNA+NyS3VQvLabx +yi3mCwHNAWDzc9dc/W0qxJd9tSY64ImoTmjtjSoxdnlocWmCTJULkY9/eFi4Ij/fhQe UwL5ychqf1cuK08H8GsIuVZoMtG+G8/qOtr8WTSMR/0BreYe9pogbsL4U8vqIU5yMbJg xPqfl++XrZK8tfQAShUqeri9OqLQiZsxSm6tDbFinygGFuarRbxMl3b2R6af5EJkPv6n jVzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=sBG3bzNJ4nIDX1Rgox6bQv5BCuW6Vs82TNv6y6/aj9o=; b=VlD+0P0P66+GIf6mXf45onI/hDe61b7MppJtpGIUNCMxZ0a7gaPF5Wws/1pk4ZzNTX 0OrQI/XzYuOfKWcxQDaFYMTWjdET6rWvgYvxUS9DUWXIqwS/0BT/BU+8zeAFrgqEfh+g 2V+kLBkNM3RQFYxfycSH5x/dyNeFXUYNSm2Y1rcRluSMUvtjqksY7N9O5I2nDx9+lxIh m8miSQJyqsxAUnknY38cIDb3CJn7K9oWu/TnTN+BzHrnZtDkg249sr8cfc2/dIcYbP2J hGFAmM4kpko970w2dSHe0eVLLbtJjrS6MhGGUhP+AkoQOBg4UYHhmhPZlmd4EEhCivpl xbXQ== X-Gm-Message-State: APjAAAUQfiHKW/UGwUs33kF+f6eYd+E0rzFEQBGmtPH2Kp59PuU42KkJ xy2zsfHta/AevIjiOJVW13+oDAI8w/qWEm2bByw= X-Google-Smtp-Source: APXvYqw9VUBNN5snuUVH+edAMsN/HpNmAh4GnV0DJaBapVld1ios5O4mjAlsTNRmtUdtapuaVTKk4ouCXXinhhz2izA= X-Received: by 2002:a02:7741:: with SMTP id g62mr5003539jac.3.1570649249342; Wed, 09 Oct 2019 12:27:29 -0700 (PDT) MIME-Version: 1.0 References: <3d5b3a12-a21c-f464-e7d1-252ccd768ff8@ti.com> <20191009173446.GL5610@atomide.com> In-Reply-To: <20191009173446.GL5610@atomide.com> From: Adam Ford Date: Wed, 9 Oct 2019 14:27:18 -0500 Message-ID: Subject: Re: Serial 8250 DMA Broken on OMAP3630 To: Tony Lindgren Cc: Vignesh Raghavendra , Greg Kroah-Hartman , Jiri Slaby , Andy Shevchenko , Douglas Anderson , Yegor Yefremov , linux-serial@vger.kernel.org, Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 9, 2019 at 12:34 PM Tony Lindgren wrote: > > * Adam Ford [191009 14:09]: > > On Wed, Oct 9, 2019 at 8:42 AM Vignesh Raghavendra wrote: > > > > > > Hi Adam, > > > > > > On 06/10/19 10:34 PM, Adam Ford wrote: > > > > Has anyone else had any issues using the CONFIG_SERIAL_8250_DMA on the OMAP? > > > > > > > > I can use the DMA on the legacy, omap-serial driver, but when I enable > > > > the DMA on the 8250-omap driver, I get missing frames in Bluetooth. > > > > > > > > The older driver seems to have an ISR that seems to address a variety > > > > of items compared to the very tiny ISR for 8250-omap.c. > > > > > > > > I am not exactly sure where to start, but if someone has any > > > > suggestions on how I can troubleshoot, please let me know. As of now, > > > > I have to disable CONFIG_SERIAL_8250_DMA to get the Bluetooth > > > > connected to UART2 operational on a DM3730 at 3,000,000 baud, but it > > > > appears to work just fine after some patches I just submitted for > > > > handling RTS/CTS. The legacy omap-serial driver works fine with DMA. > > > > > > > > > > Mainline omap-serial does not support DMA (evident from lack of > > > dmaengine API calls) and therefore is not a regression. So OMAP3 UART > > > DMA was never tested at least with 8250 driver. > > > I am not sure enabling UART DMA on OMAP3 would be a trivial job. We need > > > analyse of whether all erratas workarounds are implemented and see if > > > there any difference wrt DMA integration itself. Do we know if UART DMA > > > ever worked on OMAP3 previously? > > > > Can we disable CONFIG_SERIAL_8250_DMA from omap2plus_defconfig? As > > of right now, it's the only way I can use the Bluetooth. There are > > #ifdef's in the 8250-omap driver, so it looks like some of the hooks > > are there, but if it's incomplete, it seems like we shouldn't enable > > this config option by default yet. > > From what I recall I tested that DMA on omap3 worked fine with runtime > PM for console. Certainly there are issues still remaining though. > > If you want to disable dma for a specific port, just delete the > add /delete-property/dma-names for the port in question in your > board specific dts file. > > See 8250_omap.c for of_property_count_strings(np, "dma-names"). Thank you. That seems to have worked. I'll check the AM3517 when I have some time to see if it needs the same patch. For now, I pushed the patch to the omap mailing list for the Logic PD Torpedo board. Should we consider removing the OMAP_SERIAL from omap2plus_defconfig in the 8250 is the preferred driver? It seems odd to me that both drivers are enabled. adam > > Regards, > > Tony > >