From mboxrd@z Thu Jan 1 00:00:00 1970 From: saiprakash.ranjan@codeaurora.org Subject: Re: [PATCH 1/3] arm64: dts: qcom: sdm845: Add Coresight support Date: Sat, 12 Jan 2019 18:21:00 +0530 Message-ID: <81172d85ed7782e0db561fcf96a82d46@codeaurora.org> References: <20190111184643.GA22691@xps15> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190111184643.GA22691@xps15> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.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, >> + >> + 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. - Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation