From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 78C94BA49; Mon, 5 May 2025 18:37:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746470236; cv=none; b=fFdIW8FIlQ8hwH47zadYyDOD+HLXJCQo3q6BG6bS7Hi8hxv5+dHRFp1Et/rZRR43sYQ9qSJek/h21k8ETBArlxily4g9J2IxTU0ssKiO+NsxlNSDNaCN3lCPCpxo5pm3oQCv/fHVMXPpt0DwmNZ5mscBPe7DbcZ3geo9phFz1rE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746470236; c=relaxed/simple; bh=uY9U9yOmUL1HEVZham59KUg3v/H3UvAiLXotlR3xw/c=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=SW/gs0LezZGrOyvprUsmgS3454QuT02QGB63rS9xYCvxE9wwbuaTgI/bJxNmXnLL/hwoJOIUkrmkPujLguieuO0qI+s94yAH/dK5/AWDRM12yzNDgkha8B1Sd5i5cjpzZQMOoBIKBzKxX7BHjAsY5NVwOGCBuAl3HBQ1JiYuIec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oteTA5T4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oteTA5T4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BDE68C4CEE4; Mon, 5 May 2025 18:37:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746470235; bh=uY9U9yOmUL1HEVZham59KUg3v/H3UvAiLXotlR3xw/c=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=oteTA5T4GoCGN5Y8OQRyLswify4lv+548Iu0zTHa4ZbPAzuYHa1jlsOcTgJoCJGly 3DEgqO7LX4s9BUbFF5Pwm1sLYJiKUA5YbPn5bJNIvbyE4ibfC+XvNpmDFl0YV0yCJX /wK5mZ0ueuPoGweeAmnmr8AjlARBQVjWBtGpikGVMYDmvowWPkhWsoykYr6ViziCp0 MYSuhvjeIq/ELlIu2nF82629/34x3vJcEpGqarcPdPoZVb/sedZZc/LlU3yKI2JzeT +o91SRVHh7rlB8kazowbeQiK/U3BDBriBcjIF9Wh/S/sj93vmS/8S4RJA2D8d4n5bt O+qvHXF9T8qTQ== Date: Mon, 5 May 2025 13:37:14 -0500 From: Bjorn Helgaas To: Manivannan Sadhasivam Cc: Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , Bjorn Helgaas , Jingoo Han , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org Subject: Re: [PATCH v4 1/4] PCI: Add debugfs support for exposing PTM context Message-ID: <20250505183714.GA990024@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@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: <20250505-pcie-ptm-v4-1-02d26d51400b@linaro.org> On Mon, May 05, 2025 at 07:54:39PM +0530, Manivannan Sadhasivam wrote: > Precision Time Management (PTM) mechanism defined in PCIe spec r6.0, > sec 6.21 allows precise coordination of timing information across multiple > components in a PCIe hierarchy with independent local time clocks. > > PCI core already supports enabling PTM in the root port and endpoint > devices through PTM Extended Capability registers. But the PTM context > supported by the PTM capable components such as Root Complex (RC) and > Endpoint (EP) controllers were not exposed as of now. IIUC, the PCIe spec defines the PTM link protocol in terms of these timestamps, but it does not provide any visibility of them to software, so any visibility is device-specific. I think it's worth mentioning something to this effect. Bjorn