From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sai Prakash Ranjan Subject: Re: [PATCH 1/3] arm64: dts: qcom: sdm845: Add Coresight support Date: Tue, 15 Jan 2019 21:59:11 +0530 Message-ID: References: <20190111184643.GA22691@xps15> <81172d85ed7782e0db561fcf96a82d46@codeaurora.org> <20190114153509.GA29374@xps15> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190114153509.GA29374@xps15> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Mathieu Poirier Cc: Mark Rutland , devicetree@vger.kernel.org, Rajendra Nayak , Suzuki K Poulose , Alexander Shishkin , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, David Brown , Rob Herring , Sibi Sankar , Vivek Gautam , Leo Yan , Andy Gross , linux-arm-msm-owner@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org Hi Mathieu, On 1/14/2019 9:05 PM, Mathieu Poirier wrote: > On Sat, Jan 12, 2019 at 06:21:00PM +0530, saiprakash.ranjan@codeaurora.org wrote: >> Hi Mathieu, >> >>>> + >>>> + etm@7040000 { >>>> + compatible = "arm,coresight-etm4x", "arm,primecell"; >>>> + arm,primecell-periphid = <0x000bb95d>; >>> >>> I'm a little curious as to why you need to bypass the normal AMBA bus >>> discovery >>> method by forcing the peripheral ID. Tracers don't show up the way >>> other >>> coresight devices do at boot time? >>> >> >> Yes on some Qcom SoC's like SDM845 and also on some previous ones, for >> ETM(only) amba bus discovery method fails because of wrong pid read from the >> registers. So we have to force this primecell peripheral ids to probe etm. > > Ok, if that is the case please add a comment to explain the situation. > Otherwise someone will assuredly ask again in the future. > Sure, will add it in the next version. Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation