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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8A67EC433FE for ; Mon, 10 Oct 2022 20:27:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aY+Iz3SmItmC+Pb0BQBCD6X2VlPkasTc3p4IVs9mGBY=; b=wSF+dc3neA3HBW tBp1/gr2O5R/QMZ1MF1/otEnkdSK/3pbCo3fEv2YquTPXnqyoI+tFUDr/Eewqm3L+RB5kE1vUykRN i04PrAFbV7PZOKTQpFSTgwVGz9kMfNwphhJtBsUvPO4PSTndi2QuJIwENGWkmy5+rRZyXu71YcVOG AhzOonNRdJF4PNdeDysLucloTN44a+UKmWC12dc+Q6Tc3ZNAjdKnt3BXPGeCYWfGIiNzkP1CGM6Td nGk4DFm0v7eDoMxxwBy6n+6NJFww1PkG+9VagIh/VYdW6WYRDoA5Vu6mRM0Tw+AAiK/5lZRaT1Jzn NLpWX+MRdNWwtEnj1xEQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ohzLv-002ASc-VL; Mon, 10 Oct 2022 20:26:20 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ohzIV-00286a-4v for linux-arm-kernel@lists.infradead.org; Mon, 10 Oct 2022 20:22:48 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 55F716101C; Mon, 10 Oct 2022 20:22:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36D30C433D6; Mon, 10 Oct 2022 20:22:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1665433365; bh=CHynigbFeyVcxvAoFQLwXJcDP7G6kpYQrKkE1dE9CSc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CF5T9mxCd+XOc59MIW/z3FQPNegwAu9mRPPpzHF5fL/flQaQdxMvVKxG8OhUpN8xI UfJ0RkWL6ObjBUX6G/fCxetSew7VvVCFJkz7zEvBSoqRbb1+TBUhDmHJIOkjEGQLPn eqp3Jak+hwhrFq0IDHhRkWM358HPzOSW21aXse1A= Date: Mon, 10 Oct 2022 22:23:29 +0200 From: Greg Kroah-Hartman To: Elliot Berman Cc: Jiri Slaby , Bjorn Andersson , Murali Nalajala , Trilok Soni , Srivatsa Vaddagiri , Carl van Schaik , Prakruthi Deepak Heragu , Andy Gross , Dmitry Baryshkov , Jassi Brar , linux-arm-kernel@lists.infradead.org, Mark Rutland , Lorenzo Pieralisi , Sudeep Holla , Marc Zyngier , Rob Herring , Krzysztof Kozlowski , Jonathan Corbet , Will Deacon , Catalin Marinas , Arnd Bergmann , devicetree@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 14/14] tty: gunyah: Add tty console driver for RM Console Services Message-ID: References: <20220928195633.2348848-1-quic_eberman@quicinc.com> <20220928195633.2348848-15-quic_eberman@quicinc.com> <14d0ff9f-60f3-71cc-ea42-ceee389298ac@quicinc.com> <615493a8-449d-b105-709e-0642dfb5359b@quicinc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <615493a8-449d-b105-709e-0642dfb5359b@quicinc.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221010_132247_309192_0D962077 X-CRM114-Status: GOOD ( 25.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun, Oct 09, 2022 at 01:59:21PM -0700, Elliot Berman wrote: > > > On 10/7/2022 12:40 AM, Greg Kroah-Hartman wrote: > > On Thu, Oct 06, 2022 at 10:59:51PM -0700, Elliot Berman wrote: > > > > > > "GH" is the shorthand we've been using for "Gunyah". I didn't find > > > documentation for dynamically assigned char devices, but if it exists, I can > > > add entry for ttyGH. > > > > Why use a new name at all? Why not stick with the existing tty names > > and device numbers? > > > > I can use hvc framework, although driver-level buffering is needed on > both the get_chars/put_chars paths because: I'm not asking about the framework (although that is a good question, you need to document why this has to be new.) I'm asking why pick a new name? You will not have a name conflict in your system with this device with any other tty name right? > - get_chars wants to poll for characters, but Gunyah will push > characters to Linux > - put_chars can be called in atomic context in the printk console path. > Gunyah RM calls can sleep, so we add to buffer and queue work to > write the characters. > > I also chose to use new tty driver because the Gunyah hypervisor call to > open the console (gh_rm_console_open) can only be done after starting the > VM. Gunyah will only forward characters sent from the other VM to Linux > after the gh_rm_console_open call is made. When launching a VM, users would > want to open console before VM starts so they can get startup messages from > the VM. I planned to use the carrier_raised() to hold > tty_port_block_until_ready until the VM is started and the > gh_rm_console_open() happens. I'm sorry, but I don't understand this. Why is this all a new api at all? What about the virtio api? Why not just use that instead? thanks, greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel