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,URIBL_BLOCKED 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 C2722C4361B for ; Wed, 16 Dec 2020 09:42:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F93723102 for ; Wed, 16 Dec 2020 09:42:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725917AbgLPJl5 (ORCPT ); Wed, 16 Dec 2020 04:41:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:51938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725889AbgLPJl5 (ORCPT ); Wed, 16 Dec 2020 04:41:57 -0500 Date: Wed, 16 Dec 2020 10:42:17 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1608111676; bh=wwOdbgunRq2eKqn6jEC3Bs80LYViiIT+qaz21Cqol+s=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=U8xz+2kdTBlKXeI7J5SDrWW1/jaWVXq5kmxd/L7Hil33cr+Dn6ZWIs9+dXhF63c9j jXxlCaGd+cMoN5x6Gi6iY49Bsopmneyw7GqLTpn9Or28wGhUx1PVzIWzrs4d1icDR1 +Y9MD0ribWJJi2xNTn8xF88+79NAblfBZ8MLeHs0= From: Greg Kroah-Hartman To: Loic Poulain Cc: Manivannan Sadhasivam , Jakub Kicinski , linux-arm-msm , Hemant Kumar , open list , Jeffrey Hugo , Bhaumik Bhatt , Network Development Subject: Re: [PATCH v18 0/3] userspace MHI client interface driver Message-ID: References: <1607715903-16442-1-git-send-email-hemantk@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed, Dec 16, 2020 at 10:17:30AM +0100, Loic Poulain wrote: > Hi Folks, > > On Fri, 11 Dec 2020 at 20:45, Hemant Kumar wrote: > > > > This patch series adds support for UCI driver. UCI driver enables userspace > > clients to communicate to external MHI devices like modem. UCI driver probe > > creates standard character device file nodes for userspace clients to > > perform open, read, write, poll and release file operations. These file > > operations call MHI core layer APIs to perform data transfer using MHI bus > > to communicate with MHI device. > > > > This interface allows exposing modem control channel(s) such as QMI, MBIM, > > or AT commands to userspace which can be used to configure the modem using > > tools such as libqmi, ModemManager, minicom (for AT), etc over MHI. This is > > required as there are no kernel APIs to access modem control path for device > > configuration. Data path transporting the network payload (IP), however, is > > routed to the Linux network via the mhi-net driver. Currently driver supports > > QMI channel. libqmi is userspace MHI client which communicates to a QMI > > service using QMI channel. Please refer to > > https://www.freedesktop.org/wiki/Software/libqmi/ for additional information > > on libqmi. > > > > Patch is tested using arm64 and x86 based platform. > > Are there any blockers or unadressed comments remaining on this > series? As far as I understand, the original blocker was the net/WiFi > mention in the commit message, that caused a legitimate concern from > network maintainer. It has been clarified now that this driver is not > for exposing any channel that could be otherwise handled properly by > an existing Linux subsystem/interface. It will be especially used as a > pipe for modem QMI channel (or AT commands) in the same way as the USB > CDC-WDM driver is doing (keeping userspace compatibility). Other MHI > channels, such as network data, QRTR, etc are not exposed and > correctly bound to the corresponding Linux subsystems. > > The correlated worry was that it could be a userspace channel facility > for 'everything qualcomm', but we could say the same for other > existing busses with userspace shunt (/dev/bus/usb, /dev/i2c, > /dev/spidev, PCI UIO, UART...). Moreover, it is mitigated by the fact > that not all MHI channels are exposed by default, but only the allowed > ones (QMI in the initial version). For sure, special care must be > given to any further channel addition. It's the middle of the merge window, we can't do anything with new patches at all until 5.11-rc1 is out, so please be patient. thanks, greg k-h