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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 9D5BCC433E0 for ; Wed, 3 Feb 2021 18:41:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49D7E64E06 for ; Wed, 3 Feb 2021 18:41:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232000AbhBCSlL (ORCPT ); Wed, 3 Feb 2021 13:41:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:35844 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229979AbhBCSlK (ORCPT ); Wed, 3 Feb 2021 13:41:10 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8FD9D64F65; Wed, 3 Feb 2021 18:40:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612377630; bh=ne/VpkVjff6Ma10qaIVVWwYCBVEGioYMCeW+6BzKYTo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=tz9oqbThN853bYgekpJXUbpY7OjxGMixhA5LVVvqA0kvOa3LvdRQaeJYSGHmzhGpG mq7DhJ5yztK6omAKh3TQZNCEmJn+MLJym8cJh1nVObVoDEPEHlLbAmQbs2ojGWLALl vOp+1MfDWSgrpVuS6981DjAT4ed26Usx8jRMKP8bEasX9B5rK+bXl6jq13WVWyT5SI m9qrLIPa2eSd3Ii/CrhdSQmOeIlhW84dY9E4zfNN0WjXe9BacxlhYVpksuZzLAd3Ng 28iFSq5g0/1kGmUoooZUx+5Jrf9Y10ehFEims8qWYMcE6qFv36k85jYJyXTskxsA2D bTBYrI2wFjiXw== Date: Wed, 3 Feb 2021 10:40:28 -0800 From: Jakub Kicinski To: Loic Poulain Cc: Manivannan Sadhasivam , Greg KH , David Miller , linux-arm-msm , open list , Jeffrey Hugo , Bhaumik Bhatt , Network Development Subject: Re: [RESEND PATCH v18 0/3] userspace MHI client interface driver Message-ID: <20210203104028.62d41962@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: References: <1609958656-15064-1-git-send-email-hemantk@codeaurora.org> <20210113152625.GB30246@work> <20210201105549.GB108653@thinkpad> <20210201121322.GC108653@thinkpad> <20210202042208.GB840@work> <20210202201008.274209f9@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <835B2E08-7B84-4A02-B82F-445467D69083@linaro.org> <20210203100508.1082f73e@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed, 3 Feb 2021 19:28:28 +0100 Loic Poulain wrote: > On Wed, 3 Feb 2021 at 19:05, Jakub Kicinski wrote: > > On Wed, 03 Feb 2021 09:45:06 +0530 Manivannan Sadhasivam wrote: > > > The current patchset only supports QMI channel so I'd request you to > > > review the chardev node created for it. The QMI chardev node created > > > will be unique for the MHI bus and the number of nodes depends on the > > > MHI controllers in the system (typically 1 but not limited). > > > > If you want to add a MHI QMI driver, please write a QMI-only driver. > > This generic "userspace client interface" driver is a no go. Nobody will > > have the time and attention to police what you throw in there later. > > Think it should be seen as filtered userspace access to MHI bus > (filtered because not all channels are exposed), again it's not > specific to MHI, any bus in Linux offers that (i2c, spi, usb, serial, > etc...). It will not be specific to QMI, since we will also need it > for MBIM (modem control path), AT commands, and GPS (NMEA frames), all > these protocols are usually handled by userspace tools and not linked > to any internal Linux framework, so it would be better not having a > dedicated chardev for each of them. The more people argue for this backdoor interface the more distrustful of it we'll become. Keep going at your own peril.