From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH v5 6/9] coresight: add support for CPU debug module Date: Thu, 30 Mar 2017 16:47:59 +0100 Message-ID: References: <1490466197-29163-1-git-send-email-leo.yan@linaro.org> <1490466197-29163-7-git-send-email-leo.yan@linaro.org> <20170328165010.GA21937@linaro.org> <20170329015423.GA5035@leoy-linaro> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from foss.arm.com ([217.140.101.70]:49178 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933392AbdC3PsQ (ORCPT ); Thu, 30 Mar 2017 11:48:16 -0400 In-Reply-To: Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Mike Leach , Leo Yan Cc: Sudeep Holla , Mathieu Poirier , Jonathan Corbet , Rob Herring , Mark Rutland , Wei Xu , Catalin Marinas , Will Deacon , Andy Gross , David Brown , Michael Turquette , Stephen Boyd , Guodong Xu , John Stultz , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-clk@vger.kernel.org, Suzuki K. Poulos On 29/03/17 15:56, Mike Leach wrote: [...] > > No - EDPRCR_COREPURQ and EDPRCR_CORENPDRQ have different semantics and purposes > > EDPRCR_COREPURQ is in the debug power domain an is tied to an external > debug request that should be an input to the external (to the PE) > system power controller. > The requirement is that the system power controller powers up the core > domain and does not power it down while it remains asserted. > > EDPRCR_CORENPDRQ is in the core power domain and thus to the specific > core only. This ensures that any power control software running on > that core should emulate a power down if this is set to one. > > We cannot know the power control design of the system, so the safe > solution is to set both bits. > +1 I agree that's the safe bet. -- Regards, Sudeep From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934180AbdC3PsT (ORCPT ); Thu, 30 Mar 2017 11:48:19 -0400 Received: from foss.arm.com ([217.140.101.70]:49178 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933392AbdC3PsQ (ORCPT ); Thu, 30 Mar 2017 11:48:16 -0400 Subject: Re: [PATCH v5 6/9] coresight: add support for CPU debug module To: Mike Leach , Leo Yan References: <1490466197-29163-1-git-send-email-leo.yan@linaro.org> <1490466197-29163-7-git-send-email-leo.yan@linaro.org> <20170328165010.GA21937@linaro.org> <20170329015423.GA5035@leoy-linaro> Cc: Sudeep Holla , Mathieu Poirier , Jonathan Corbet , Rob Herring , Mark Rutland , Wei Xu , Catalin Marinas , Will Deacon , Andy Gross , David Brown , Michael Turquette , Stephen Boyd , Guodong Xu , John Stultz , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-clk@vger.kernel.org, "Suzuki K. Poulose" From: Sudeep Holla Organization: ARM Message-ID: Date: Thu, 30 Mar 2017 16:47:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/03/17 15:56, Mike Leach wrote: [...] > > No - EDPRCR_COREPURQ and EDPRCR_CORENPDRQ have different semantics and purposes > > EDPRCR_COREPURQ is in the debug power domain an is tied to an external > debug request that should be an input to the external (to the PE) > system power controller. > The requirement is that the system power controller powers up the core > domain and does not power it down while it remains asserted. > > EDPRCR_CORENPDRQ is in the core power domain and thus to the specific > core only. This ensures that any power control software running on > that core should emulate a power down if this is set to one. > > We cannot know the power control design of the system, so the safe > solution is to set both bits. > +1 I agree that's the safe bet. -- Regards, Sudeep From mboxrd@z Thu Jan 1 00:00:00 1970 From: sudeep.holla@arm.com (Sudeep Holla) Date: Thu, 30 Mar 2017 16:47:59 +0100 Subject: [PATCH v5 6/9] coresight: add support for CPU debug module In-Reply-To: References: <1490466197-29163-1-git-send-email-leo.yan@linaro.org> <1490466197-29163-7-git-send-email-leo.yan@linaro.org> <20170328165010.GA21937@linaro.org> <20170329015423.GA5035@leoy-linaro> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 29/03/17 15:56, Mike Leach wrote: [...] > > No - EDPRCR_COREPURQ and EDPRCR_CORENPDRQ have different semantics and purposes > > EDPRCR_COREPURQ is in the debug power domain an is tied to an external > debug request that should be an input to the external (to the PE) > system power controller. > The requirement is that the system power controller powers up the core > domain and does not power it down while it remains asserted. > > EDPRCR_CORENPDRQ is in the core power domain and thus to the specific > core only. This ensures that any power control software running on > that core should emulate a power down if this is set to one. > > We cannot know the power control design of the system, so the safe > solution is to set both bits. > +1 I agree that's the safe bet. -- Regards, Sudeep