From patchwork Thu Sep 30 16:05:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnaud Pouliquen X-Patchwork-Id: 12528839 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D8AEC4332F for ; Thu, 30 Sep 2021 16:13:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5652761507 for ; Thu, 30 Sep 2021 16:13:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349091AbhI3QPL (ORCPT ); Thu, 30 Sep 2021 12:15:11 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:42636 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1349136AbhI3QPF (ORCPT ); Thu, 30 Sep 2021 12:15:05 -0400 Received: from pps.filterd (m0046660.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 18UDFMr6004359; Thu, 30 Sep 2021 18:13:07 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=selector1; bh=WA2LajeF8VZdGihemfmP2b2B7HQnkua+zsIiBEQnIes=; b=jqCwMr8hAUj3QE0DQ/lUL/U+cP3lJQ0ZpoEDXf/glIsUxSueryOwxbypgVlcZPoMxYi1 cJQsVNEsurgQ+PGYqC/JHkBGurU/lK1bds2p6l9Suiw8fO79K5SLMdiP+rcfPRKX7Tz4 8im7SSjQdCYjOPIXEPdQEdBz6OE7U8zL6bW5fBzUKg5guI/DE3ruuk5kTOJiwP+t8Tg2 x4Zm352KZ6Kp9sFX+3DwkBKiq66krZ+HlPRO3d6teICQ3Rx0sZ1ySfbxZWrQJoBqWgsq FLzz/cdEqMIItXvVeDU50DDEKJ75bfwISVTIwt9l9ihVlZqz559PX1G1Sy+WYDV2ljNo Rw== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 3bddy9rymu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 30 Sep 2021 18:13:07 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 0952E10002A; Thu, 30 Sep 2021 18:13:05 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag2node2.st.com [10.75.127.5]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id EF521238687; Thu, 30 Sep 2021 18:13:04 +0200 (CEST) Received: from localhost (10.75.127.46) by SFHDAG2NODE2.st.com (10.75.127.5) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Thu, 30 Sep 2021 18:13:04 +0200 From: Arnaud Pouliquen To: Ohad Ben-Cohen , Bjorn Andersson , Jonathan Corbet , Mathieu Poirier CC: Greg Kroah-Hartman , Jiri Slaby , , Suman Anna , , , , Subject: [PATCH v8 0/2] Add rpmsg tty driver Date: Thu, 30 Sep 2021 18:05:18 +0200 Message-ID: <20210930160520.19678-1-arnaud.pouliquen@foss.st.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG2NODE2.st.com (10.75.127.5) To SFHDAG2NODE2.st.com (10.75.127.5) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.182.1,Aquarius:18.0.790,Hydra:6.0.391,FMLib:17.0.607.475 definitions=2021-09-30_05,2021-09-30_01,2020-04-07_01 Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org This new revision reopens subject started a long time ago. Previous revision discussions available here [1]. This patchset introduces a TTY console on top of the RPMsg framework which enables the following use cases: - Provide a console to communicate easily with the remote processor application. - Provide an interface to get the remote processor log traces without ring buffer limitation. - Ease the migration from MPU + MCU processors to multi core processors (MPU and MCU integrated in one processor) by offering a virtual serial link. An alternative of this proposed solution would consist in using the virtio console: The drawback with that solution is that it requires a specific virtio buffer (in addition to the one already used for RPMsg) which does not fit with remote processors with little memory. The proposed solution allows to multiplex the console with the other rpmsg services, optimizing the memory. The first patch adds an API to the rpmsg framework ('get max transmission unit') and the second one is the rpmsg tty driver itself. Update vs previous revision [1]: - simplify the patch by removing the control part(CTS) to keep only the stream part. - rebase on kernel V5.15-rc1 - take into account v7 review comments. Notice that I kept the Acked-by and Reviewed-by in "rpmsg: core: add API to get MTU" commit even though I'm not sure if it's still relevant after such a long period... [1] https://lkml.org/lkml/2020/3/24/1394 Arnaud Pouliquen (2): rpmsg: core: add API to get MTU tty: add rpmsg driver Documentation/serial/tty_rpmsg.rst | 15 ++ drivers/rpmsg/rpmsg_core.c | 21 +++ drivers/rpmsg/rpmsg_internal.h | 2 + drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++ drivers/tty/Kconfig | 9 + drivers/tty/Makefile | 1 + drivers/tty/rpmsg_tty.c | 275 +++++++++++++++++++++++++++++ include/linux/rpmsg.h | 10 ++ 8 files changed, 343 insertions(+) create mode 100644 Documentation/serial/tty_rpmsg.rst create mode 100644 drivers/tty/rpmsg_tty.c