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=-8.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 4EAA9C4363D for ; Thu, 1 Oct 2020 02:36:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2D182087D for ; Thu, 1 Oct 2020 02:36:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dsiK3+Vj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730198AbgJACg2 (ORCPT ); Wed, 30 Sep 2020 22:36:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725372AbgJACg2 (ORCPT ); Wed, 30 Sep 2020 22:36:28 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5BF6C061755 for ; Wed, 30 Sep 2020 19:36:26 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id jw11so1050735pjb.0 for ; Wed, 30 Sep 2020 19:36:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=8KYXszwQ89hkONVI1ysv2NZoMsEiEw8904Ywg8FUfkI=; b=dsiK3+Vj2bBXVcrL67SxMoRMBWNkQPZ8K+qgnGyOIJOTCtoMu80p+h4ro17ocKE1Gv kGwTcV/1jq2e9BNZ9sq+oNvhg5KeKoeQymFm4AN3yyH1am0xh3kNmo29B6TiBBQarHQy rl5V7UfHz6uv/DbSe0kYmhXRaxvq8YRLyzN2AOc0bgguVfLPX3zq/84VIuBHP2MLuHUs C5EbeVfZINz3HldQ1dbl3tRToDOcvR8QunaBug3+fKms2nu4UL6a+nPWwtW8yFD4mFQX CO4TiITnzoBX0HbCoFtqKbPSkbZKK3Dj0YwkSvMurlBtOID5+xqK0jYC5Z6jxQYkMTFK /QRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=8KYXszwQ89hkONVI1ysv2NZoMsEiEw8904Ywg8FUfkI=; b=omUAwSBqeYc6+F3FO5Zwqn05gSDF3ibRdYxfP3HYxlmIVKbV82e2S5JuaRndCiAbjw HyxkBxxcTYeK7qEu9BWHwtigEX0HvXJxWv6VnYIGw/PPfmPvjPTU+NeaP+0Ok2aN9re/ nc5FWyqnVL7uMJ0+c9m0CkomHOu/JbegC8lAX02H4UQDIQA2WU+mcJAPd63/IAEf3TIC lQn0XNbED8TSxdtaC9U051gpgymC0cebN8pzBI/epmgMC1ROp3PnsaRoyx30V4D9u6C5 fl8lWjspb+HnVTNcXAU9PU1Oi/fv5e+C4FtU4UMCEVHY1CxO8EKd/b1ESHicCMpfIgoC 4mgw== X-Gm-Message-State: AOAM530z9Ku+zpdITpteAqNTwuET4aZUQJp3pbiN1sF6ej3mt4EYBsO9 45lAjn6sTkBVCm9g0UgALfo= X-Google-Smtp-Source: ABdhPJzIIRGx7RUVV7WCyOmJVN0hmuT6ALzxoLXlc5pjTJwYYLi5KjiiR1iYyYv9AsMo0+1IWPIJxQ== X-Received: by 2002:a17:90a:760f:: with SMTP id s15mr5034135pjk.214.1601519786250; Wed, 30 Sep 2020 19:36:26 -0700 (PDT) Received: from [10.230.29.112] ([192.19.223.252]) by smtp.gmail.com with ESMTPSA id z1sm3405278pgu.80.2020.09.30.19.36.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Sep 2020 19:36:25 -0700 (PDT) Subject: Re: [PATCH v5 15/15] misc: bcm-vk: add ttyVK support To: Scott Branden , Arnd Bergmann , Greg Kroah-Hartman , Olof Johansson Cc: Kees Cook , linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com References: <20201001012810.4172-1-scott.branden@broadcom.com> <20201001012810.4172-16-scott.branden@broadcom.com> From: Florian Fainelli Message-ID: <278afb05-8c8d-98d2-eed0-f73b954b03c7@gmail.com> Date: Wed, 30 Sep 2020 19:36:19 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0 Thunderbird/78.3.1 MIME-Version: 1.0 In-Reply-To: <20201001012810.4172-16-scott.branden@broadcom.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/30/2020 6:28 PM, Scott Branden wrote: > Add ttyVK support to driver to allow console access to VK card from host. > > Device node will be in the follow form /dev/bcm-vk.x_ttyVKy where: > x is the instance of the VK card > y is the tty device number on the VK card > > Signed-off-by: Scott Branden Was it not possible to: - emulate a standard 8250 UART and just expose an additional bar + MSI vector such that one could get a debug UART out of this device with little to no work on the host side? - or use virtio console and implement virtio on the firmware that runs on VK? It's not a lot of code, but it just feels like this should not have to be done at all. -- Florian