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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8EAC3C433EF for ; Wed, 19 Jan 2022 06:32:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351784AbiASGcK (ORCPT ); Wed, 19 Jan 2022 01:32:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350142AbiASGcJ (ORCPT ); Wed, 19 Jan 2022 01:32:09 -0500 X-Greylist: delayed 400 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 18 Jan 2022 22:32:08 PST Received: from mail.kernel-space.org (unknown [IPv6:2a01:4f8:c2c:5a84::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7DADFC061574; Tue, 18 Jan 2022 22:32:08 -0800 (PST) Received: from ziongate (localhost [127.0.0.1]) by ziongate (OpenSMTPD) with ESMTP id 439408cc; Wed, 19 Jan 2022 06:25:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=simple; d=kernel-space.org; h=date :from:to:cc:subject:in-reply-to:message-id:references :mime-version:content-type; s=default; bh=s2ZSs/PKN1DSOLrxonrNUr JXLFs=; b=FFl/L2e5n9Dss43S2mb3AijX09FGjDAVuagYKtR/DOITA9+qGJHCna B9imOZLJjJlqeJAdrt7HCQn/LWbFtEdHLgD4ZGow25Me9QyahO7my4Ez539/LzUJ /UcTebk6jroiCO/VWuXrl1Ch8Pf285Y3NRqGY7s/gKqsJfPqeHVrY= DomainKey-Signature: a=rsa-sha1; c=simple; d=kernel-space.org; h=date :from:to:cc:subject:in-reply-to:message-id:references :mime-version:content-type; q=dns; s=default; b=sxzxGa9shXLeeLXp M+8UL81kODdWqJN2zDuBlnwk474hTW5UzyOmtHQUD2JLM7xNrz/9Q7800SKr0veS xk2R8h6TWLQUf4dCF/En2b9POBlkMqIOjSKyPhmMSSPyk/TNzDbUSjl6gp0pkeJe oHZUqI8FtTrDa2aC/XevhvWygmo= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-space.org; s=20190913; t=1642573525; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FQiF7uSbYYHDzY09oc6psHu+j2M09N/5yPqOvHCHhJw=; b=TfrGJ9QkUyCnq4jKzWsVc5/X31/P7m4xsgODpHU4BihZKo81fQOQWT6IDuQCYF30EiqJt6 mnAD8yGh0/mEAiJ2eeDPzK1phiCJtSC8vjLbQA31+c1XES0EpdKQ+mXe5aheck9bM626c/ ITtMPv2hvYElHpkJM1qTKmGQCscOkQg= Received: from dfj (host-79-40-232-124.business.telecomitalia.it [79.40.232.124]) by ziongate (OpenSMTPD) with ESMTPSA id e7f79889 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 19 Jan 2022 06:25:25 +0000 (UTC) Date: Wed, 19 Jan 2022 07:25:21 +0100 (CET) From: Angelo Dureghello To: Marc Kleine-Budde cc: gerg@linux-m68k.org, geert@linux-m68k.org, linux-m68k@vger.kernel.org, linux-can@vger.kernel.org, qiangqing.zhang@nxp.com, Dario Binacchi Subject: Re: mcf5441x: flexcan FIFO and mailbox mode (was: Re: [PATCH v5 5/5] can: flexcan: add mcf5441x support) In-Reply-To: <20220106111847.zjkrghehxr7mrkkt@pengutronix.de> Message-ID: <1cf937d1-1e26-e611-c85f-f9e2128c225@kernel-space.org> References: <20220106111847.zjkrghehxr7mrkkt@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Precedence: bulk List-ID: X-Mailing-List: linux-m68k@vger.kernel.org Hi Marc, On Thu, 6 Jan 2022, Marc Kleine-Budde wrote: > Hello Angelo, > > On 02.07.2021 11:48:41, Angelo Dureghello wrote: >> Add flexcan support for NXP ColdFire mcf5441x family. >> >> This flexcan module is quite similar to imx6 flexcan module, but >> with some exceptions: >> >> - 3 separate interrupt sources, MB, BOFF and ERR, >> - implements 16 mb only, >> - m68k architecture is not supporting devicetrees, so a >> platform data check/case has been added, >> - ColdFire is m68k, so big-endian cpu, with a little-endian flexcan >> module. > > we're currently discussing the option that the user of a flexcan can > switch between RX-FIFO and RX via mailboxes. > > I noticed that the mcf5441x currently is configured for FIFO mode. Have > you tested the driver in mailbox mode? > > The reason that some cores use the FIFO mode is, that they cannot > receive RTR CAN frames in mailbox mode. According to the IP core > overview table, the mcf5441x can receive RTR frames. > > If the IP core supports reception of RTR frames, mailbox mode should be > used, as it makes use of more buffers (16-2) instead of 6 in FIFO mode. > Should we activate mailbox mode for the mcf5441x? > Ok, not sure why i selected FIFO mode initially, my application actually is quite simple. Will try the switch to mailbox, sure, looking into this. > regards, > Marc > Regards, angelo > -- > Pengutronix e.K. | Marc Kleine-Budde | > Embedded Linux | https://www.pengutronix.de | > Vertretung West/Dortmund | Phone: +49-231-2826-924 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | >