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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 CC374C83004 for ; Tue, 28 Apr 2020 18:57:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB30420BED for ; Tue, 28 Apr 2020 18:57:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="pLpSfEmL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729921AbgD1S55 (ORCPT ); Tue, 28 Apr 2020 14:57:57 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:17624 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729674AbgD1S54 (ORCPT ); Tue, 28 Apr 2020 14:57:56 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1588100276; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=2Y6b36ayyOGCJzSMhx0uz2jc0TRSogQ1Q1n9GsQYtto=; b=pLpSfEmLBXhit+7uA4M8b8WIye545rAC/D52ePMVwhw/4yTU0A5vxpIAjUgaxhJCjjdjqSwZ O3LRIdTOzdnLH6hSd9DT7JQCd2bWm4AOyDAATCU2Z845m0rFXPO8qGfGTrtAZX1++HmNLTGl vgBgO26ppP39oA85Fw01bKHmuz8= X-Mailgun-Sending-Ip: 104.130.122.27 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 mxa.mailgun.org with ESMTP id 5ea87cb3.7f844196e570-smtp-out-n03; Tue, 28 Apr 2020 18:57:55 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id DE93CC44788; Tue, 28 Apr 2020 18:57:54 +0000 (UTC) Received: from [10.46.162.249] (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: hemantk) by smtp.codeaurora.org (Postfix) with ESMTPSA id BBCCAC4478F; Tue, 28 Apr 2020 18:57:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org BBCCAC4478F 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=none smtp.mailfrom=hemantk@codeaurora.org Subject: Re: [PATCH v3 6/6] bus: mhi: core: Fix channel device name conflict To: Jeffrey Hugo , manivannan.sadhasivam@linaro.org Cc: bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org References: <1588003153-13139-1-git-send-email-jhugo@codeaurora.org> <1588003153-13139-7-git-send-email-jhugo@codeaurora.org> From: Hemant Kumar Message-ID: <72519148-a677-bfdf-05fc-f14cc3e3bffd@codeaurora.org> Date: Tue, 28 Apr 2020 11:57:53 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <1588003153-13139-7-git-send-email-jhugo@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 4/27/20 8:59 AM, Jeffrey Hugo wrote: > When multiple instances of the same MHI product are present in a system, > we can see a splat from mhi_create_devices() - "sysfs: cannot create > duplicate filename". > > This is because the device names assigned to the MHI channel devices are > non-unique. They consist of the channel's name, and the channel's pipe > id. For identical products, each instance is going to have the same > set of channel (both in name and pipe id). > > To fix this, we prepend the device name of the parent device that the > MHI channels belong to. Since different instances of the same product > should have unique device names, this makes the MHI channel devices for > each product also unique. > > Additionally, remove the pipe id from the MHI channel device name. This > is an internal detail to the MHI product that provides little value, and > imposes too much device specific internal details to userspace. It is > expected that channel with a specific name (ie "SAHARA") has a specific > client, and it does not matter what pipe id that channel is enumerated on. > The pipe id is an internal detail between the MHI bus, and the hardware. > The client is not expected to make decisions based on the pipe id, and to > do so would require the client to have intimate knowledge of the hardware, > which is inappropiate as it may violate the layering provided by the MHI > bus. The limitation of doing this is that each product may only have one > instance of a channel by a unique name. This limitation is appropriate > given the usecases of MHI channels. > > Signed-off-by: Jeffrey Hugo > --- Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project