From 1bcf245c837bc66fdaddea222bab9eb5c978a9d7 Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Tue, 20 Jan 2026 23:17:40 +0530 Subject: [PATCH] PCI: dwc: Return -ENODEV from dw_pcie_wait_for_link() if device is not found The dw_pcie_wait_for_link() function waits up to 1 second for the PCIe link to come up and returns -ETIMEDOUT for all failures without distinguishing cases where no device is present on the bus. But the callers may want to just skip the failure if the device is not found on the bus and handle failure for other reasons. So after timeout, if the LTSSM is in Detect.Quiet or Detect.Active state, return -ENODEV to indicate the callers that the device is not found on the bus and return -ETIMEDOUT otherwise. Also add kernel doc to document the parameter and return values. Signed-off-by: Manivannan Sadhasivam Tested-by: Richard Zhu Tested-by: Vincent Guittot Reviewed-by: Shawn Lin Reviewed-by: Niklas Cassel Link: https://patch.msgid.link/20260120-pci-dwc-suspend-rework-v4-1-2f32d5082549@oss.qualcomm.com --- drivers/pci/controller/dwc/pcie-designware.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index 345365ea97c7..55c1c60f7f8f 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -692,9 +692,16 @@ void dw_pcie_disable_atu(struct dw_pcie *pci, u32 dir, int index) dw_pcie_writel_atu(pci, dir, index, PCIE_ATU_REGION_CTRL2, 0); } +/** + * dw_pcie_wait_for_link - Wait for the PCIe link to be up + * @pci: DWC instance + * + * Returns: 0 if link is up, -ENODEV if device is not found, -ETIMEDOUT if the + * link fails to come up for other reasons. + */ int dw_pcie_wait_for_link(struct dw_pcie *pci) { - u32 offset, val; + u32 offset, val, ltssm; int retries; /* Check if the link is up or not */ @@ -706,6 +713,17 @@ int dw_pcie_wait_for_link(struct dw_pcie *pci) } if (retries >= PCIE_LINK_WAIT_MAX_RETRIES) { + /* + * If the link is in Detect.Quiet or Detect.Active state, it + * indicates that no device is detected. + */ + ltssm = dw_pcie_get_ltssm(pci); + if (ltssm == DW_PCIE_LTSSM_DETECT_QUIET || + ltssm == DW_PCIE_LTSSM_DETECT_ACT) { + dev_info(pci->dev, "Device not found\n"); + return -ENODEV; + } + dev_info(pci->dev, "Phy link never came up\n"); return -ETIMEDOUT; } -- 2.47.3