Messages in this thread |  | | From | Hans Zhang <> | | Subject | [PATCH 0/2] PCI: cadence: Add 100 ms delay after link up for speeds > 5 GT/s | | Date | Fri, 1 May 2026 23:35:51 +0800 |
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As per PCIe r6.0, sec 6.6.1, a Downstream Port that supports Link speeds greater than 5.0 GT/s, software must wait a minimum of 100 ms after Link training completes before sending a Configuration Request.
The same requirement has already been addressed for the Synopsys DesignWare PCIe controller in commit 80dc18a0cba8d ("PCI: dwc: Ensure that dw_pcie_wait_for_link() waits 100 ms after link up").
This series implements the required delay for the Cadence PCIe controller.
Patch 1 introduces a 'max_link_speed' field in struct cdns_pcie and adds the delay logic in cdns_pcie_host_wait_for_link(). Since max_link_speed defaults to 0, the delay is not yet triggered. This patch prepares the infrastructure and references the DWC implementation.
Patch 2 sets the max_link_speed value in the TI J721E glue driver based on the maximum supported link speed (obtained from the device tree "max-link-speed" property), thereby activating the delay when the controller supports speeds greater than 5 GT/s.
Other Cadence-based glue drivers can be updated similarly in follow-up work.
--- Our company's product is based on the HPA IP from Cadence. When connecting to different devices, we encountered issues with the enumeration failure when connecting to the NVIDIA RTX5070 GPU and the NVMe SSD with PCIe 5.0 interface. Our code is based on: 80dc18a0cba8d ("PCI: dwc: Ensure that dw_pcie_wait_for_link() waits 100 ms after link up"). ---
Hans Zhang (2): PCI: cadence: Ensure that cdns_pcie_host_wait_for_link() waits 100 ms after link up PCI: j721e: Set max_link_speed to enable 100 ms delay after link up
drivers/pci/controller/cadence/pci-j721e.c | 1 + .../pci/controller/cadence/pcie-cadence-host-common.c | 9 +++++++++ drivers/pci/controller/cadence/pcie-cadence.h | 2 ++ 3 files changed, 12 insertions(+)
base-commit: e75a43c7cec459a07d91ed17de4de13ede2b7758 -- 2.34.1
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