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 227B8C197A0 for ; Fri, 17 Nov 2023 07:06:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230079AbjKQHGR (ORCPT ); Fri, 17 Nov 2023 02:06:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbjKQHGM (ORCPT ); Fri, 17 Nov 2023 02:06:12 -0500 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C7AE8D51 for ; Thu, 16 Nov 2023 23:06:08 -0800 (PST) Received: by mail-pf1-x42a.google.com with SMTP id d2e1a72fcca58-6be1bc5aa1cso1718101b3a.3 for ; Thu, 16 Nov 2023 23:06:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1700204768; x=1700809568; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=BFhGxb0d8TVHFbBvoHAaCR3/jKcNUFSpf4eO7oktV0o=; b=Rk/Ufp4id45FS1KHVTcsmp8qVJOK0u75InRd9TU06rhk27DweuT3NdJKbhmciYNAi5 AYTYzw1pX2svy2/V8mnzV2872pW/i7RlV0OV4J+VWi3UTxfUrioqteRAbpKz3uBXWgQS nJsIn29P/C65JSPJvrBJMEW97pFrD/HEApoQW9VoqmrP1SJeYayDyt+UKp0IcggEcV8Y WNvzC5Zr6UAm23MKpq+P1N+E/U52qjWpQfJ3dIEZzhqMNaPQgrTIduYcZrrs1hD+vaYT IOsHUT/1BEKQUtRyqtt5avbhmZjwwoRZ+Jc+GHdGP6Gk2hpH/SPUAKx5AdddW3XK+1Zg A+eg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700204768; x=1700809568; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=BFhGxb0d8TVHFbBvoHAaCR3/jKcNUFSpf4eO7oktV0o=; b=RqbtA+SLnG+CnPeovGrWYryhkT98BO/DmiX/twdw+NS+fXbevdPxmXaoY81nrWM5+2 UlrEqccAkVMSqlcEBI5vCFokLx3E3SIxnLuwsItdvduf4XAFOfU6c1NFXs6QorZc703l gOW0gd6ATnz9ziQLAeAFCweTzQ1oeYlcv2mYtKNq9iwB5UGcSMIhkHFVhMFkgqxrIabL 13ey+TtsdHFflEMSclQVXqW4fCGYF1Q/ACa+duqRjB8tw6NhNUwZSlqOqk01crx6zyrj dRpsudVSlLlZH6HQBwKhv/pIsJfGVXbBBobuLxjX5oT7PgiSw8mOQaJJHKvFqodOg3rZ C85w== X-Gm-Message-State: AOJu0Yy275Q6iIk8y5XenbrGndEVQkiE0rMkBhpgsASYR219/m8At+sk OsY58refVT77ZlwPzUflmHJI X-Google-Smtp-Source: AGHT+IGfIVkXhPOQhA7r6TpFkqTZFEQ5G2MrI3+aG3pqqr9Ey+8Q4SuY6v/Fxjje7LBfSrP37jc2EQ== X-Received: by 2002:a05:6a21:6d96:b0:186:4430:5d16 with SMTP id wl22-20020a056a216d9600b0018644305d16mr19580645pzb.61.1700204768220; Thu, 16 Nov 2023 23:06:08 -0800 (PST) Received: from thinkpad ([103.28.246.177]) by smtp.gmail.com with ESMTPSA id z13-20020a056a00240d00b006c320b9897fsm785013pfh.126.2023.11.16.23.06.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Nov 2023 23:06:07 -0800 (PST) Date: Fri, 17 Nov 2023 12:36:02 +0530 From: Manivannan Sadhasivam To: Jakub Kicinski Cc: davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, loic.poulain@linaro.org Subject: Re: [PATCH v2 0/2] Add MHI Endpoint network driver Message-ID: <20231117070602.GA10361@thinkpad> References: <20230607152427.108607-1-manivannan.sadhasivam@linaro.org> <20230607094922.43106896@kernel.org> <20230607171153.GA109456@thinkpad> <20230607104350.03a51711@kernel.org> <20230608123720.GC5672@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230608123720.GC5672@thinkpad> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jakub, On Thu, Jun 08, 2023 at 06:07:20PM +0530, Manivannan Sadhasivam wrote: > On Wed, Jun 07, 2023 at 10:43:50AM -0700, Jakub Kicinski wrote: > > On Wed, 7 Jun 2023 22:41:53 +0530 Manivannan Sadhasivam wrote: > > > > In any case, I'm opposed to reuse of the networking stack to talk > > > > to firmware. It's a local device. The networking subsystem doesn't > > > > have to cater to fake networks. Please carry: > > > > > > > > Nacked-by: Jakub Kicinski > > > > > > > > if there are future submissions. > > > > > > Why shouldn't it be? With this kind of setup one could share the data connectivity > > > available in the device with the host over IP tunneling. If the IP source in the > > > device (like modem DSP) has no way to be shared with the host, then those IP > > > packets could be tunneled through this interface for providing connectivity to > > > the host. > > > > > > I believe this is a common usecase among the PCIe based wireless endpoint > > > devices. > > > > We can handwave our way into many scenarios and terrible architectures. > > I don't see any compelling reason to merge this. > > These kind of usecases exist in the products out there in the market. Regarding > your comment on "opposed to reuse of the network stack to talk to firmware", it > not the just the firmware, it is the device in general that is talking to the > host over this interface. And I don't see how different it is from the host > perspective. > > And these kind of scenarios exist with all types of interfaces like usb-gadget, > virtio etc... So not sure why the rule is different for networking subsystem. > Sorry to revive this old thread, this discussion seems to have fell through the cracks... As I explained above, other interfaces also expose this kind of functionality between host and the device. One of the credible usecase with this driver is sharing the network connectivity available in either host or the device with the other end. To make it clear, we have 2 kind of channels exposed by MHI for networking. 1. IP_SW0 2. IP_HW0 IP_SW0 is useful in scenarios I explained above and IP_HW0 is purely used to provide data connectivity to the host machines with the help of modem IP in the device. And the host side stack is already well supported in mainline. With the proposed driver, Linux can run on the device itself and it will give Qcom a chance to get rid of their proprietary firmware used on the PCIe endpoint devices like modems, etc... - Mani > - Mani > > -- > மணிவண்ணன் சதாசிவம் -- மணிவண்ணன் சதாசிவம்