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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 3AC9CC34021 for ; Mon, 17 Feb 2020 17:50:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1269520725 for ; Mon, 17 Feb 2020 17:50:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="eivdHkGY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728901AbgBQRul (ORCPT ); Mon, 17 Feb 2020 12:50:41 -0500 Received: from mail-pg1-f194.google.com ([209.85.215.194]:45569 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728889AbgBQRul (ORCPT ); Mon, 17 Feb 2020 12:50:41 -0500 Received: by mail-pg1-f194.google.com with SMTP id b9so9439568pgk.12 for ; Mon, 17 Feb 2020 09:50:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=V0F+CPlKBaYQp5ssJ6bvuOMjKgVSOet/nt7N4287yH0=; b=eivdHkGY/h+F9sRcScDOmV2CopnSm90PCYLIK8F9DeG35We8fcAhf8d8MPRxelEmVC MmGHS2k/W4DnfPk1k1yQjyWopT8RJihoEy4H+cxgllhqwx8MdPC1IZiE0xH9/aygZdXx IyE26geE5wo/h9w/uccwHzNAf2WVtzbWFpImdnFraSasHIRtXhurOjtVdH11iVO0Tuqv 1QODAiLxt6BChWR0oCWKg0fOrJEwJOLRAaVqIZq4oRyImSCGEjRP1AoFweca5042ODUi yCVXHom366cEAg8OHjqLlRb2LiWR1begT5JBn0hCnVC4zgsJB0scgwuQ4esxEeiXX3PQ zyDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=V0F+CPlKBaYQp5ssJ6bvuOMjKgVSOet/nt7N4287yH0=; b=XANq5mrSc1ftaqOTKkM3VsjrHiOFK0PwIgUC/g75DrtNeWJBhsnEejnqDS6NdW9KaX /RrBd9D8mc/561QuFjHGs070rZUIXybgJNP7Nt9e3YEuWC4PvJgIBq4jxuPbpo8+LTCB VR/5CZjCeKf/xUwQEcugtYOK47xb9AfXx5r5kwojBYRmmYvPRwSNjDuQ7lbV/YxZyngl DerA1R1o4WqAOpr57cydKEYTsNg7kNdKeTKY1O7fDI2mGks7SfpgPTNDoPr7qlAyW8pw i3xfRIPsw9G9SdDgsgeY7VemaT64ilFGr41Y1HySWuFEefp6et/YQL+IeagX61VF6882 uHyQ== X-Gm-Message-State: APjAAAX0NqpDU8G3Q3T9rzGB3ihEmvwDDhHGI35EJnPeN06msDF2EWP8 H/639X/8C2qHFnsSaYFEIzKj X-Google-Smtp-Source: APXvYqwKIWYg4tOk1K2R+x/r28aatJUvrwXdBU/TrnBbBBKka5uFGaIMFJ+sdVvybQrMohx11V2hzA== X-Received: by 2002:a63:7207:: with SMTP id n7mr18948000pgc.253.1581961840426; Mon, 17 Feb 2020 09:50:40 -0800 (PST) Received: from Mani-XPS-13-9360 ([2409:4072:48d:3349:2df9:3778:ccac:a356]) by smtp.gmail.com with ESMTPSA id z64sm1153357pfz.23.2020.02.17.09.50.34 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 17 Feb 2020 09:50:39 -0800 (PST) Date: Mon, 17 Feb 2020 23:20:31 +0530 From: Manivannan Sadhasivam To: Greg KH Cc: Arnd Bergmann , smohanad@codeaurora.org, Jeffrey Hugo , Kalle Valo , Bjorn Andersson , hemantk@codeaurora.org, linux-arm-msm , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v2 02/16] bus: mhi: core: Add support for registering MHI controllers Message-ID: <20200217175031.GC7305@Mani-XPS-13-9360> References: <20200213152013.GB15010@mani> <20200213153418.GA3623121@kroah.com> <20200213154809.GA26953@mani> <20200213155302.GA3635465@kroah.com> <20200217052743.GA4809@Mani-XPS-13-9360> <20200217115930.GA218071@kroah.com> <20200217130419.GA13993@Mani-XPS-13-9360> <20200217141503.GA1110972@kroah.com> <20200217163205.GE1502885@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200217163205.GE1502885@kroah.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, Feb 17, 2020 at 05:32:05PM +0100, Greg KH wrote: > On Mon, Feb 17, 2020 at 05:04:52PM +0100, Arnd Bergmann wrote: > > On Mon, Feb 17, 2020 at 3:15 PM Greg KH wrote: > > > On Mon, Feb 17, 2020 at 06:34:19PM +0530, Manivannan Sadhasivam wrote: > > > > On Mon, Feb 17, 2020 at 12:59:30PM +0100, Greg KH wrote: > > > > ``` > > > > struct mhi_device *mhi_alloc_device(struct mhi_controller *mhi_cntrl) > > > > { > > > > ... > > > > dev->parent = mhi_cntrl->dev; > > > > ... > > > > ``` > > > > > > > > Hence, having the parent dev pointer really helps. > > > > > > Yes, saving the parent device is fine, but you should be doing your own > > > dma calls using _your_ device, not the parents. Only mess with the > > > parent pointer if you need to do something "normal" for a parent. > > > > The MHI device is not involved in DMA at all, as it is not a DMA master, > > and has no knowledge of the memory management or whether there > > is any DMA at all. I think it is the right abstraction for an MHI driver to > > pass kernel pointers into the subsystem interfaces, which then get > > mapped by the bus driver that owns the DMA master. > > > > This is similar to how e.g. USB drivers pass data into the USB core > > interfaces, which then get the HCI driver to map/unmap it into the > > DMA masters. > > Ok, then this needs to be named a whole lot better than the original > "dev" name had it. Heck, even "parent" does not show that type of > representation, make it "controller" or something else a whole lot more > descriptive of what it really is please. > Okay. I'll come up with something more relative. Thanks, Mani > thanks, > > greg k-h