From: Bjorn Helgaas <helgaas@kernel.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: "Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Jingoo Han" <jingoohan1@gmail.com>,
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
Date: Mon, 5 May 2025 13:37:14 -0500 [thread overview]
Message-ID: <20250505183714.GA990024@bhelgaas> (raw)
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
next prev parent reply other threads:[~2025-05-05 18:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-05 14:24 [PATCH v4 0/4] PCI: Add PTM debugfs support Manivannan Sadhasivam
2025-05-05 14:24 ` [PATCH v4 1/4] PCI: Add debugfs support for exposing PTM context Manivannan Sadhasivam
2025-05-05 18:37 ` Bjorn Helgaas [this message]
2025-05-10 6:20 ` Manivannan Sadhasivam
2025-06-07 2:55 ` Eric Biggers
2025-05-05 14:24 ` [PATCH v4 2/4] PCI: dwc: Pass DWC PCIe mode to dwc_pcie_debugfs_init() Manivannan Sadhasivam
2025-05-05 18:37 ` Bjorn Helgaas
2025-05-10 6:21 ` Manivannan Sadhasivam
2025-05-05 14:24 ` [PATCH v4 3/4] PCI: dwc: Add debugfs support for PTM context Manivannan Sadhasivam
2025-06-17 23:12 ` Bjorn Helgaas
2025-06-30 20:51 ` Bjorn Helgaas
2025-05-05 14:24 ` [PATCH v4 4/4] PCI: qcom-ep: Mask PTM_UPDATING interrupt Manivannan Sadhasivam
2025-05-10 6:20 ` [PATCH v4 0/4] PCI: Add PTM debugfs support Manivannan Sadhasivam
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