From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1182B1632DD for ; Tue, 21 Apr 2026 14:23:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776781390; cv=none; b=b816amu2hTh1iPadnvS/B8xdFIE8J4Zv+fOeNPWmcrPChvkTjtuZWnKATAmUejlyLpdTEp38ZQ7idpxL4/pDi8ne4bWqOOGDsGKWFhMtMb475m77Hy41AOBEpvNdaFvQpWI8j7tThPRTF0M/omOIOUyD/bd4DyuV9siCr8BDFZk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776781390; c=relaxed/simple; bh=KM8s3Go6l2LinwodbbP9q2DHUf200LaOlGtLx14cocs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E6sz/ryX2tynKLLIBddomBwrbL9nAcQYIzCzJJ9l8MuGpyWx2LAvw9d8tJOgKrWdrRkPy4J57UJrLUZvmX1EMRR3GVUcrZfJMSGH/g7ZDuIvWgvU/591yXsDIaKFcsty0Dz4+2sYkbzTmVvQI29rYORdFZmY1QqbFOAUCmu4/tQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=CmfR+UJq; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="CmfR+UJq" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BF05325DC; Tue, 21 Apr 2026 07:23:02 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.1.197.6]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 315553F915; Tue, 21 Apr 2026 07:23:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1776781388; bh=KM8s3Go6l2LinwodbbP9q2DHUf200LaOlGtLx14cocs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CmfR+UJqltBJNaPJGqeM1P3Hn7uquZiUo7Tucn8eYQehbesNLVsN+ejUGefkf5ZBt 22PYhattW5vBD73xTVajKCb10u2UvnGclQJDjqh05rxzseu9e28QpCMqr+jVvsENy7 cvr4wKWdtbx5QtXKAV9258/ZwuTUXR9SFnv0ocYI= Date: Tue, 21 Apr 2026 15:23:04 +0100 From: Yeoreum Yun To: Mike Leach Cc: Suzuki K Poulose , Leo Yan , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, james.clark@linaro.org, alexander.shishkin@linux.intel.com, jie.gan@oss.qualcomm.com Subject: Re: [PATCH v5 04/12] coresight: etm4x: exclude ss_status from drvdata->config Message-ID: References: <20260415165528.3369607-1-yeoreum.yun@arm.com> <20260415165528.3369607-5-yeoreum.yun@arm.com> <20260416155118.GM356832@e132581.arm.com> <57dbea1b-670b-4b8f-a590-1d4239bc2c76@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hi Mike, > Hi, > > On 4/21/26 11:30, Yeoreum Yun wrote: > > > Hi Mike, > > > > > > > Hi, > > > > > > > > This register [bit 31] indicates if a single shot comparator has matched. So > > > > read-back provides information to the user post run to determine which if > > > > any of the comparators set in this way has actually matched. > > > > > > Okay. so after disable sysfs session, to check former session > > > check whether comprator has matched. > > > > > > > > > > > Moreover, the specification states "Software must reset this bit to 0 to > > > > re-enable single-shot control" and "Reset state is unknown. STATUS must be > > > > written to set an initial state...." > > > > > > > > Therefore this register must be written as part of any configuration so > > > > should be available in the drvdata->config for both read and write, > > > > > > But I don't think this is the reason for locate ss_status into "config" > > > since its write purpose is not to configure but the "clear" former bit. > > > That's why I think it's enough to clear when the new sysfs session starts. > > > > > > > IOW, I think it's better to remove ss_status from configfs item > > and > > - add field ss_cmp in etm4_cpas > > - add another field ss_status under "etm4_drvdata" to show "PENDING > > and STATUS" bits to sysfs after finishing session. > > > > Is is valid for you? > > > > No. Why two different locations for a single register read? If I have the > ETMv4 hardware manual I am going to look for a something that is > recognizable as being related to the single shot comparator status > register(s). > > So in sysfs I would expect to see all the bits from the register, displayed, > without masking off the STATUS and PENDING bits as happens now. > > In the code I would expect to see a single location with a sensible name - > ss_cmp doesn't really correlate terribly well with TRCSSCSR. If you do not > like the original ss_status, then ss_cmp_status may actually be better, > ss_cmp could be either the ss comparator status or control register. Fine. But I'm still we don't need consider ss_status as configfs item. So it's enough to move ss_status under etm4_drvdata from etm4_config and use it. -- Sincerely, Yeoreum Yun