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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DFF0C43217 for ; Tue, 12 Oct 2021 07:45:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65EFA60D43 for ; Tue, 12 Oct 2021 07:45:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234404AbhJLHr5 (ORCPT ); Tue, 12 Oct 2021 03:47:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234412AbhJLHrz (ORCPT ); Tue, 12 Oct 2021 03:47:55 -0400 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F30FC061753 for ; Tue, 12 Oct 2021 00:45:53 -0700 (PDT) Received: by mail-pj1-x102b.google.com with SMTP id lk8-20020a17090b33c800b001a0a284fcc2so1276428pjb.2 for ; Tue, 12 Oct 2021 00:45:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Wi0c4tUU6/JGllRDmGdUEE9qbUz1Hxlfkgo8Ug//VqI=; b=OUxL16y8OmpzrNyur4IFOl0tTdwiz9ylmxi9Jz2OpNnLfrhiIcxcYNAKAtWNt5nRLP c7ip3cn40UaBwURsC/aeYBU5Xg3qM7yswY4I7N1K6tce9m0PPyjVuLQrwdbTFO2iWs6S O5TcZDGIOg+GE93gGGafo79sbCW61kSV65N8sff/xeVhNe6kQtp3ZeQU9OCtUl6EsdGU 4Ypz3M5x1LHJ2ICYAufaJ1YX2k9P30nz41mdEuLU9/JMmYDuUTr8Ck85Om35SwC6S9+L 8ZDjqICUBLABNaiQ5kDBjWvI7JgX9cyAjJ+V3CpsLjM6i/guib33L8AzcMJ3KtXdcSNh Fefg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Wi0c4tUU6/JGllRDmGdUEE9qbUz1Hxlfkgo8Ug//VqI=; b=kSR3eM4FlafyxIKgq0qZMmmTNeQeK2DrCCAU0qZxwvTA0yMwQivH+dY8KM+pFtWd94 Kp4CYHS5jwi2ObHtJexNa4si2ouc3wgmETGbz6QyymwYzLCi4T+GfhsudLPj4MvcNIRj +DPfPyqcAqlRqMdsb4YGkK/pKRm2TM0/3xtyVCM+0yen0eKasZCwssHXH7rMSInXfyPI Ktzz071lK6xIYi8xMJQQYtJCrzn8jb5ev1EzM3jlnQ86C5GVopkVT9xK2SkE6i3jNN9c X8EloDvKuDFT8s7W20rzdo5rETXKkDMqgdUuO73FeFtWqxfGl57bzAc41f1inkb76D3g nElA== X-Gm-Message-State: AOAM532OBh6uKAO0+ejpDQdXPoWFry+bqCxp5+VEiulIw74D3JKv4/5s 6K6vSKWZ1N0r+b1/iokJfi+6q3KRZb4N9XuszTRxzA== X-Google-Smtp-Source: ABdhPJwVHKfgQcm4qq1ccDhtz6vH6TbKhIs9LDuLpCHmbkxwmiNRZagXnDeh2jLu9tT+KFW0b0YqHmzObsxOEOl2YqI= X-Received: by 2002:a17:90b:370f:: with SMTP id mg15mr4208394pjb.209.1634024752384; Tue, 12 Oct 2021 00:45:52 -0700 (PDT) MIME-Version: 1.0 References: <20211011141733.3999-1-stephan@gerhold.net> <20211011141733.3999-5-stephan@gerhold.net> In-Reply-To: From: Loic Poulain Date: Tue, 12 Oct 2021 09:55:48 +0200 Message-ID: Subject: Re: [PATCH net-next v2 4/4] net: wwan: Add Qualcomm BAM-DMUX WWAN network driver To: Stephan Gerhold Cc: "David S. Miller" , Jakub Kicinski , Sergey Ryazanov , Johannes Berg , Bjorn Andersson , Andy Gross , Vinod Koul , Rob Herring , Aleksander Morgado , Network Development , linux-arm-msm , dmaengine@vger.kernel.org, devicetree , open list , phone-devel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Jeffrey Hugo Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi Stephan, On Mon, 11 Oct 2021 at 16:51, Stephan Gerhold wrote: > > Like in the RFC version [1], the driver does not currently use the link > > management of the WWAN subsystem. Instead, it simply exposes one network > > interface for each of the up to 8 channels. > > > > This setup works out of the box with all available open-source userspace > > WWAN implementations, especially ModemManager (no changes needed). > > oFono works too although it requires minor changes to support WWAN control > > ports (/dev/wwan0qmi0) which are independent of BAM-DMUX (already provided > > by the "rpmsg_wwan_ctrl" driver). > > It was easy to support because the setup is very similar to ones already > > supported for USB modems. Some of them provide multiple network interfaces > > and ModemManager can bundle them together to a single modem. > > > > I believe it is best to keep this setup as-is for now and not add even > > more complexity to userspace with another setup that works only in this > > particular configuration. I will reply to this patch separately to explain > > that a bit more clearly. This patch is already long enough as-is. :) > > > > [1]: https://lore.kernel.org/netdev/20210719145317.79692-5-stephan@gerhold.net/ > > > > The main goal of the WWAN link management is to make the multiplexing > setup transparent to userspace. Unfortunately it's still unclear to me > how or even if this can be achieved for the many different different > setups that exist for Qualcomm modems. To show that more clearly I'll > "briefly" list the various currently supported setups in ModemManager > (there might be even more that I am not even aware of). The goal is also to have a common hierarchy, with the network link being a child of the WWAN device, as for the control ports. Making it easier for the user side to find the relation between all these devices. Moreover, it allows having a common set of attributes, like the LINK ID, and possibly new ones in the future. I mean it's probably fine if you create a static set of network devices and do not support dynamic link creation, but I think they should be created in some way via the WWAN subsystem, and get the same attributes (link id), we can have special meaning link ids (-1) for e.g. non context specific netdevs (e.g. for rmnet/qmap transport iface). Regards, Loic