From patchwork Thu Dec 3 22:45:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hemant Kumar X-Patchwork-Id: 11949841 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=-16.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 5334AC433FE for ; Thu, 3 Dec 2020 22:52:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5B982245C for ; Thu, 3 Dec 2020 22:52:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731832AbgLCWwX (ORCPT ); Thu, 3 Dec 2020 17:52:23 -0500 Received: from m43-15.mailgun.net ([69.72.43.15]:24942 "EHLO m43-15.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730482AbgLCWwX (ORCPT ); Thu, 3 Dec 2020 17:52:23 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1607035922; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=yneIfdaseUAg7oSHUMq1XthCRxBcTj7aSJWNLSkOLfk=; b=O4YQn4upak/+m/iUa4ozTGsXO9zXRCKwlDjURX0SvFAu76UO0/+66B945REJka6ea5A5GQtW 5vZ19AG9GEjffrtcIIy74lBXhRIC4CZXIeNir+opu48c4Kb/sdHqNrXEOyEDhppwDcZo2Nwm weHPlVsz4JCTJ3IA2I7QpzMYzwU= X-Mailgun-Sending-Ip: 69.72.43.15 X-Mailgun-Sid: WyJiZjI2MiIsICJuZXRkZXZAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n05.prod.us-west-2.postgun.com with SMTP id 5fc96a86dc0fd8a31718fe68 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 03 Dec 2020 22:45:26 GMT Sender: hemantk=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id AD926C43464; Thu, 3 Dec 2020 22:45:26 +0000 (UTC) Received: from codeaurora.org (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: hemantk) by smtp.codeaurora.org (Postfix) with ESMTPSA id 18747C433CA; Thu, 3 Dec 2020 22:45:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 18747C433CA Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=hemantk@codeaurora.org From: Hemant Kumar To: manivannan.sadhasivam@linaro.org, gregkh@linuxfoundation.org Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, jhugo@codeaurora.org, bbhatt@codeaurora.org, loic.poulain@linaro.org, netdev@vger.kernel.org, Hemant Kumar Subject: [PATCH v15 3/4] docs: Add documentation for userspace client interface Date: Thu, 3 Dec 2020 14:45:15 -0800 Message-Id: <1607035516-3093-4-git-send-email-hemantk@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1607035516-3093-1-git-send-email-hemantk@codeaurora.org> References: <1607035516-3093-1-git-send-email-hemantk@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 96 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 0000000..df1f0c4 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,95 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================= +Userspace Client Interface (UCI) +================================= + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +========== + +open +---- + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read +---- + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +----- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll +---- + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. When the uplink channel transfer ring is non-empty, more +data may be sent to the device. Returns EPOLLERR when UCI driver is removed. + +release +------- + +Decrements UCI device reference count and UCI channel reference count. Upon +last release() UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage +===== + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +----------------------------------- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~~~~~~~~~~~~~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: + Model: 'FN980m' + +Other Use Cases +--------------- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host).