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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 606F7C48BE5 for ; Mon, 21 Jun 2021 17:25:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4682A60FF2 for ; Mon, 21 Jun 2021 17:25:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231444AbhFUR1u (ORCPT ); Mon, 21 Jun 2021 13:27:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231396AbhFUR1r (ORCPT ); Mon, 21 Jun 2021 13:27:47 -0400 Received: from mail-oi1-x22c.google.com (mail-oi1-x22c.google.com [IPv6:2607:f8b0:4864:20::22c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F5F2C061756 for ; Mon, 21 Jun 2021 10:25:32 -0700 (PDT) Received: by mail-oi1-x22c.google.com with SMTP id w1so7491343oie.13 for ; Mon, 21 Jun 2021 10:25:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=PnPX+kMwwqow5LYukSPE/j5CcoTy7NRtog3utuQq2IE=; b=IlM4/QIr6kXMDieXq2favI4BOm+o5ZxnHdZwUYTjCqrBZSaWC4gwwIF+F4B9F5qSdf aixUjWQLgS/AXi3OR7McxgHlOKNSFUlc5g8bEKu9UXwxwf9AWPQ4i/9DyNe9ICC96o0z KXXcpuxr22bkxc2HK8qkfH9ZOQKs907KKN6SL4471gnxBZfLveRLtNG/2P3sUyGNT0K5 tiK962EvGmj2OJ/2eAMO7IcauWF3j/t64jubulaqCaE5JZZ94PVrXN+lDT9dpBDyomDp IqPIGpw72Sz99ly/1y5ASkIq/xzK1JWnDxNmEiFazMrjkUnxkFj6UFfRxO4Cp/r+TIz8 Tgmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=PnPX+kMwwqow5LYukSPE/j5CcoTy7NRtog3utuQq2IE=; b=FxZU5VMV0q21x0+H0UnzIJ5fdUsNzydvM39najJIpdESGeVr0A0Z5OZAZMp0XBdw0e q3XO5lxU8YWbNv/NrMfxQ3pFLNR89l3Li79CSilup+/MvD1GzpNiPaxPrXarxQyw5GZr xSTnBrH90Ey941XE5tVpFY9BqzjtlOPs5X8ut+tSf+7zJKWj58C4A8732EmL/iAWSVZ0 vsKujsXzl/jJucyEBi5olX/ON12ysOzdqBZp+VlDbWM2U91sL1xjaSp3nqs4CIQUCEnp tBwYuhSB+mij08TExzkQq3J8nKskrgcYfXOPlQH7M5k9NPxuv5mzpwcO7ziDCWn/CF+D 97jA== X-Gm-Message-State: AOAM5339I3UapFfmP8vTAm8uvcDCb1r3yqINWh0lCAS4Sk5TNEQ2Wam2 gt4p3Tj/P6N0nd/mOUgrxdahbg== X-Google-Smtp-Source: ABdhPJyoXPEE4Y+PUiCrrS+ozWk1/WGyHTeIxyXg0SQgO/W4PkuHBbK13rxi4TsTt6HtaEnAmw6ebQ== X-Received: by 2002:aca:b38a:: with SMTP id c132mr17388459oif.90.1624296331567; Mon, 21 Jun 2021 10:25:31 -0700 (PDT) Received: from yoga (104-57-184-186.lightspeed.austtx.sbcglobal.net. [104.57.184.186]) by smtp.gmail.com with ESMTPSA id u10sm4235029otj.75.2021.06.21.10.25.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Jun 2021 10:25:31 -0700 (PDT) Date: Mon, 21 Jun 2021 12:25:28 -0500 From: Bjorn Andersson To: "Enrico Weigelt, metux IT consult" Cc: Linus Walleij , Viresh Kumar , Geert Uytterhoeven , Bartosz Golaszewski , "Enrico Weigelt, metux IT consult" , Viresh Kumar , "Michael S. Tsirkin" , Jason Wang , Vincent Guittot , Bill Mills , Alex Benn?e , stratos-dev@op-lists.linaro.org, "open list:GPIO SUBSYSTEM" , linux-kernel , Stefan Hajnoczi , "Stefano Garzarella --cc virtualization @ lists . linux-foundation . org" , virtualization@lists.linux-foundation.org, Alistair Strachan Subject: Re: [PATCH V3 1/3] gpio: Add virtio-gpio driver Message-ID: References: <10442926ae8a65f716bfc23f32339a6b35e51d5a.1623326176.git.viresh.kumar@linaro.org> <8d58da79-8e54-048b-db89-8c1caaa0320f@metux.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8d58da79-8e54-048b-db89-8c1caaa0320f@metux.net> Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Wed 16 Jun 10:52 CDT 2021, Enrico Weigelt, metux IT consult wrote: > On 16.06.21 05:30, Bjorn Andersson wrote: > > > Combined with the virtio-i2c effort this could provide an alternative by > > simply tunneling the busses and GPIOs into Linux and use standard iio > > drivers, for cases where this suits your product requirements better. > > So, you wanna use virtio as logical interface between the two CPUs ? > Interesting idea. Usually folks use rpmsg for those things. > rpmsg is a layer on top of virtio, so this would be an extension of the existing model. There's been discussions (and I believe some implementations) related to bridging I2C requests over rpmsg, but I think it's preferable to standardize around the virtio based bearer directly. > What is running on the secondary CPU ? Some OS like Linux or some bare > metal stuff ? What kind of CPU is that anyways ? > These ideas revolves around platforms that implements something like the "Android Sensor Hub", which provides some resource constraint co-processor that deals with sensor device interaction and processing of the data without waking up the power-hungry ARM cores. Given the focus on power consumption I would guess that these are not going to run Linux. Core-wise I've seen this implemented using primarily ARM and Hexagon cores. Regards, Bjorn 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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 5CF6BC49EA6 for ; Mon, 21 Jun 2021 17:25:37 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 11EC06109E for ; Mon, 21 Jun 2021 17:25:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 11EC06109E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id C6F04607C2; Mon, 21 Jun 2021 17:25:36 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id s6BTMbo8XApz; Mon, 21 Jun 2021 17:25:36 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTPS id 6D9A760791; Mon, 21 Jun 2021 17:25:35 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 32C1CC0010; Mon, 21 Jun 2021 17:25:35 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 01203C000C for ; Mon, 21 Jun 2021 17:25:34 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id E2F33403CF for ; Mon, 21 Jun 2021 17:25:33 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=linaro.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Jde5zUfFcuoi for ; Mon, 21 Jun 2021 17:25:32 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-oi1-x236.google.com (mail-oi1-x236.google.com [IPv6:2607:f8b0:4864:20::236]) by smtp4.osuosl.org (Postfix) with ESMTPS id 9EDF7403CE for ; Mon, 21 Jun 2021 17:25:32 +0000 (UTC) Received: by mail-oi1-x236.google.com with SMTP id t40so20696524oiw.8 for ; Mon, 21 Jun 2021 10:25:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=PnPX+kMwwqow5LYukSPE/j5CcoTy7NRtog3utuQq2IE=; b=IlM4/QIr6kXMDieXq2favI4BOm+o5ZxnHdZwUYTjCqrBZSaWC4gwwIF+F4B9F5qSdf aixUjWQLgS/AXi3OR7McxgHlOKNSFUlc5g8bEKu9UXwxwf9AWPQ4i/9DyNe9ICC96o0z KXXcpuxr22bkxc2HK8qkfH9ZOQKs907KKN6SL4471gnxBZfLveRLtNG/2P3sUyGNT0K5 tiK962EvGmj2OJ/2eAMO7IcauWF3j/t64jubulaqCaE5JZZ94PVrXN+lDT9dpBDyomDp IqPIGpw72Sz99ly/1y5ASkIq/xzK1JWnDxNmEiFazMrjkUnxkFj6UFfRxO4Cp/r+TIz8 Tgmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=PnPX+kMwwqow5LYukSPE/j5CcoTy7NRtog3utuQq2IE=; b=pG38Vxs3CCipnmFIGxztH0b8NU8MZVAf1SOw6ljagUi/838J86c1SSks+g2MmWCfdw m/UUGshI0NZC9eLex/mfey6gb8jL0P3zXtdhMhFRRvx5wN7cvgX/cwe8qoLQWGY+Vk5x 28miw0q866aYn8hlKBLjdkx4D6VBVw7HU9my8FKUK0GSzIQNGIVWLl+U1H1xsNOrc2RT byc/bSprjw1ZvbnovJGEl7gsK1+BR3OiF3gp+cYOu2ozSabnhMWTGRjert4Z0IQNanZ5 ARBFiS8CraTLa14Z2Dfqi3mVwMD4HNOKSPBkbjlW3GwpWi25EAd/r0qzOZ1ubQ7lLTET 6iMQ== X-Gm-Message-State: AOAM533zAI0CWXweyvwbMw3RF/F4shNwERBhecBYwv9PPpMreBhNYY4/ BLmwh+/yy4rxdQLDGh+BDKCE1A== X-Google-Smtp-Source: ABdhPJyoXPEE4Y+PUiCrrS+ozWk1/WGyHTeIxyXg0SQgO/W4PkuHBbK13rxi4TsTt6HtaEnAmw6ebQ== X-Received: by 2002:aca:b38a:: with SMTP id c132mr17388459oif.90.1624296331567; Mon, 21 Jun 2021 10:25:31 -0700 (PDT) Received: from yoga (104-57-184-186.lightspeed.austtx.sbcglobal.net. [104.57.184.186]) by smtp.gmail.com with ESMTPSA id u10sm4235029otj.75.2021.06.21.10.25.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Jun 2021 10:25:31 -0700 (PDT) Date: Mon, 21 Jun 2021 12:25:28 -0500 From: Bjorn Andersson To: "Enrico Weigelt, metux IT consult" Subject: Re: [PATCH V3 1/3] gpio: Add virtio-gpio driver Message-ID: References: <10442926ae8a65f716bfc23f32339a6b35e51d5a.1623326176.git.viresh.kumar@linaro.org> <8d58da79-8e54-048b-db89-8c1caaa0320f@metux.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8d58da79-8e54-048b-db89-8c1caaa0320f@metux.net> Cc: Alistair Strachan , Vincent Guittot , Stefan Hajnoczi , Geert Uytterhoeven , "Michael S. Tsirkin" , Viresh Kumar , Linus Walleij , linux-kernel , virtualization@lists.linux-foundation.org, Bartosz Golaszewski , "open list:GPIO SUBSYSTEM" , Viresh Kumar , stratos-dev@op-lists.linaro.org, "Enrico Weigelt, metux IT consult" , Bill Mills X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Wed 16 Jun 10:52 CDT 2021, Enrico Weigelt, metux IT consult wrote: > On 16.06.21 05:30, Bjorn Andersson wrote: > > > Combined with the virtio-i2c effort this could provide an alternative by > > simply tunneling the busses and GPIOs into Linux and use standard iio > > drivers, for cases where this suits your product requirements better. > > So, you wanna use virtio as logical interface between the two CPUs ? > Interesting idea. Usually folks use rpmsg for those things. > rpmsg is a layer on top of virtio, so this would be an extension of the existing model. There's been discussions (and I believe some implementations) related to bridging I2C requests over rpmsg, but I think it's preferable to standardize around the virtio based bearer directly. > What is running on the secondary CPU ? Some OS like Linux or some bare > metal stuff ? What kind of CPU is that anyways ? > These ideas revolves around platforms that implements something like the "Android Sensor Hub", which provides some resource constraint co-processor that deals with sensor device interaction and processing of the data without waking up the power-hungry ARM cores. Given the focus on power consumption I would guess that these are not going to run Linux. Core-wise I've seen this implemented using primarily ARM and Hexagon cores. Regards, Bjorn _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization