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_PASS,URIBL_BLOCKED autolearn=ham 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 10FF1C10F0E for ; Mon, 15 Apr 2019 18:31:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D299520854 for ; Mon, 15 Apr 2019 18:31:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="K0FS+TkX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728069AbfDOSb5 (ORCPT ); Mon, 15 Apr 2019 14:31:57 -0400 Received: from mail-ot1-f65.google.com ([209.85.210.65]:44960 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727836AbfDOSb5 (ORCPT ); Mon, 15 Apr 2019 14:31:57 -0400 Received: by mail-ot1-f65.google.com with SMTP id d24so15303928otl.11; Mon, 15 Apr 2019 11:31:57 -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=cVLj8tFQS/ywsn/qSFpfdC+Yrm0GXk+bPV9Sg4B6QHQ=; b=K0FS+TkXPNMN+3ALGJaEe5RntkIHoN3Aff4IfPZjKTFpMTq88CMIwwCBhqrcDE02cD CKMK6D3gG0zpwj52dCjV3SqoPxFFGq3WYhZMl6otyjHpaQ3aWY6ELN/in+MK+/baSW/a i8Crt48EQn50rhJ7XOyNmg3fyk5P0QczoF7USRX/1/TCUkJ1opaHxKYgCtDIjL0oMXyJ JkupFuH5qJWZHL5XZ9GAxrALpX/9jOmWeU+4sx2Owzu9K5DyxlBthPUwJlCBlbm691Gh 8LaEaPnVqrLDRfNYGqMJdRsEhNSqo61Yz9Fe06Xy/1GfxZ8HPu2NiIEAdlefVaKGRhSS cdqA== 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=cVLj8tFQS/ywsn/qSFpfdC+Yrm0GXk+bPV9Sg4B6QHQ=; b=XgFlABJvqqhrA//6D+SpjhdZwabBj8SqzPvlCC/7t5UnsKbDIbZ/9WF+u5kTa4GSmB q4yv54y5QcqZNm9mELf8xeWs/50WUOGLwyFemTvMhV5tvCbKGjrjsJVmdGHuF2VdRzOq +u/bR/HNbPALjh9EAfOq5JdL6rEQqmX7HG53trQ7Rn6Cdaho6LEEyr+xu4jIEstBmPOQ GsE1CccrfgMKTWTQEysZbZ73S23A0EFvX/9VTMPrSNTBQhoIdGy+3nRGX0VC5lCatByz SSIS3v3R61EcD1hrx0Gjqry0gf3HIWXAVaEJaa3AHdn+yIgXwRtl2MnpiHC3GBNusFxK UBqg== X-Gm-Message-State: APjAAAX+UyfPyZYHTY4NraJvhReVcgruAbjhiTwKL2cT9NmzEUDxi4wk ngq7alByTKgW409RZ629pWUwF2utz2HKi82LFLk= X-Google-Smtp-Source: APXvYqytP3RLvk3Qr4DfWeuC01A6q/elvfqzd3rKimjq3LjCWwFyDkN3n9Hb5BPR+WOYJig83PB4TC2iN4t2dccA3Gc= X-Received: by 2002:a05:6830:153:: with SMTP id j19mr43431876otp.248.1555353116552; Mon, 15 Apr 2019 11:31:56 -0700 (PDT) MIME-Version: 1.0 References: <20190409144250.7237-1-TheSven73@gmail.com> <982e69c6-4e68-6f62-8bed-cd5a1802272b@metux.net> In-Reply-To: <982e69c6-4e68-6f62-8bed-cd5a1802272b@metux.net> From: Sven Van Asbroeck Date: Mon, 15 Apr 2019 14:31:45 -0400 Message-ID: Subject: Re: [PATCH v10 0/7] Add Fieldbus subsystem + support HMS Profinet card To: "Enrico Weigelt, metux IT consult" Cc: Rob Herring , Linus Walleij , Lee Jones , mark.rutland@arm.com, =?UTF-8?Q?Andreas_F=C3=A4rber?= , treding@nvidia.com, David Lechner , noralf@tronnes.org, johan@kernel.org, Michal Simek , michal.vokac@ysoft.com, Arnd Bergmann , Greg KH , john.garry@huawei.com, geert+renesas@glider.be, robin.murphy@arm.com, Paul Gortmaker , sebastien.bourdelin@savoirfairelinux.com, icenowy@aosc.io, Stuart Yoder , "J. Kiszka" , maxime.ripard@bootlin.com, Linux Kernel Mailing List , netdev 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 Hi Enrico, Thanks for your input, appreciate it ! On Mon, Apr 15, 2019 at 1:41 PM Enrico Weigelt, metux IT consult wrote: > > AFAIK, "fieldbus" is a bit broader term than just the typical IEC61158- > style remote memory stuff. At least that's the terminology my clients > tend to use (eg. they also call some homebbrewn rs485-based protocols > "fieldbus"). > > Maybe it would be better calling it "IEC-61158" instead of "fieldbus" ? > Yes, we are certainly open to that, if it is more correct and/or better accepted by users. > > By the way: can this device be opened/used by several processes > simultaniously ? > Yes. You can open as many handles to the device as you like, they will all share the fieldbus memory. When the remote fieldbus memory changes, that event will be broadcast to all open handles, via poll/select. Of course if your application is monitoring the fieldbus memory in more than one thread/process, you may need to guard against race conditions. There is no guarantee which thread/process will react to the change first. Sven