From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965143AbcATWTs (ORCPT ); Wed, 20 Jan 2016 17:19:48 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:47566 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965051AbcATWSd (ORCPT ); Wed, 20 Jan 2016 17:18:33 -0500 Subject: Re: [PATCH V12 3/7] dma: add Qualcomm Technologies HIDMA management driver To: Mark Rutland References: <1452523550-8920-1-git-send-email-okaya@codeaurora.org> <1452523550-8920-4-git-send-email-okaya@codeaurora.org> <20160115145629.GI3262@leverpostej> <56990CD4.6020405@arm.com> <20160115153656.GM3262@leverpostej> <569917C7.9000804@codeaurora.org> Cc: Marc Zyngier , dmaengine@vger.kernel.org, timur@codeaurora.org, devicetree@vger.kernel.org, cov@codeaurora.org, vinod.koul@intel.com, jcm@redhat.com, agross@codeaurora.org, arnd@arndb.de, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu, christoffer.dall@linaro.org From: Sinan Kaya Message-ID: <56A007B5.9070502@codeaurora.org> Date: Wed, 20 Jan 2016 17:18:29 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <569917C7.9000804@codeaurora.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mark, On 1/15/2016 11:01 AM, Sinan Kaya wrote: >> I'm concerned with how this is safe, and with the userspace interface. >> > e.g. if the user wants to up the QoS for a VM, how to they find the >> > right channel in sysfs to alter? > The HW supports changing the QoS values on the flight. In order to locate the > object, I'm exporting a > > I tried to address your concern on v10 last series. Here is brief summary. > > Each channel device has a sysfs entry named chid. > What: /sys/devices/platform/hidma-*/chid > + /sys/devices/platform/QCOM8061:*/chid > > > Each management object has one priority and weight file per channel. > +What: /sys/devices/platform/hidma-mgmt*/chanops/chan*/priority > + /sys/devices/platform/QCOM8060:*/chanops/chan*/priority > > Suppose you want to change the priority of a channel you assigned to guess, > the userspace application goes and reads the chid value of the channel. > > Then goes to chanops/chan/ directory and can change priority and weight > parameters here. > > Here is how the directory looks like. QCOM8060:00 is a management object. > QCOM8061:0x are the channel objects. > > /sys/devices/platform/QCOM8060:00# ls > QCOM8061:00 > QCOM8061:01 > QCOM8061:02 > QCOM8061:03 > QCOM8061:04 > QCOM8061:05 > chanops > > > > > Did this answer your question? I'm capturing all the questions and answers as FAQ into the cover letter as I keep repeating myself for every single reviewer. Besides from the "lack of documentation", is there any code related change you'd like to discuss in the series. -- Sinan Kaya Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project