From patchwork Sat Oct 17 04:04:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hemant Kumar X-Patchwork-Id: 11842597 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1D4DD15E6 for ; Sat, 17 Oct 2020 06:00:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB76A2076A for ; Sat, 17 Oct 2020 06:00:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="GMnsOa3J" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436803AbgJQGAi (ORCPT ); Sat, 17 Oct 2020 02:00:38 -0400 Received: from z5.mailgun.us ([104.130.96.5]:18931 "EHLO z5.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436865AbgJQGAh (ORCPT ); Sat, 17 Oct 2020 02:00:37 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1602914437; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=HT/R9yUZLHwn3pMf/0k5BOEAUmeENiqSjIZIsp0nOeY=; b=GMnsOa3JwYcLSIxDCBFHBaHGTLsoHKSDzMAviZI5TbJdkdWuWi5b9j4RBx5rFSWZUqkE40oF zWe9yifKWyNWv9SKoPZ4MBp+HH/tRlX+irv9pb/xW9H/JqtztNNA/WNXPIPdUTyjPcLw3eJU +Em/pe7cMl/HWjwhTUHyoi5vSUk= X-Mailgun-Sending-Ip: 104.130.96.5 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n01.prod.us-west-2.postgun.com with SMTP id 5f8a6d4b42f9861fb11c9d8d (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Sat, 17 Oct 2020 04:04:27 GMT Sender: hemantk=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 07F76C433CB; Sat, 17 Oct 2020 04:04:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-caf-mail-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=ALL_TRUSTED,BAYES_00,SPF_FAIL autolearn=no autolearn_force=no version=3.4.0 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 F0B50C433C9; Sat, 17 Oct 2020 04:04:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org F0B50C433C9 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, Hemant Kumar Subject: [PATCH v7 0/4] userspace MHI client interface driver Date: Fri, 16 Oct 2020 21:04:13 -0700 Message-Id: <1602907457-13680-1-git-send-email-hemantk@codeaurora.org> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org This patch series adds support for UCI driver. 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. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 based platform. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: Added mutex lock to prevent multiple readers to access same mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 39 +++ drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile | 4 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 661 ++++++++++++++++++++++++++++++++++++++++ include/linux/mhi.h | 12 + 8 files changed, 742 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c