kernel/linux.git/drivers/pci/controller/dwc, branch v6.12.92

PCI: tegra194: Fix CBB timeout caused by DBI access before core power-on

2026-05-23T11:04:35+00:00

[ Upstream commit 34b3eef48d980cd37b876e128bbf314f69fb5d70 ] When PERST# is deasserted twice (assert -> deassert -> assert -> deassert), a CBB (Control Backbone) timeout occurs at DBI register offset 0x8bc (PCIE_MISC_CONTROL_1_OFF). This happens because pci_epc_deinit_notify() and dw_pcie_ep_cleanup() are called before reset_control_deassert() powers on the controller core. The call chain that causes the timeout: pex_ep_event_pex_rst_deassert() pci_epc_deinit_notify() pci_epf_test_epc_deinit() pci_epf_test_clear_bar() pci_epc_clear_bar() dw_pcie_ep_clear_bar() __dw_pcie_ep_reset_bar() dw_pcie_dbi_ro_wr_en() <- Accesses 0x8bc DBI register reset_control_deassert(pcie->core_rst) <- Core powered on HERE The DBI registers, including PCIE_MISC_CONTROL_1_OFF (0x8bc), are only accessible after the controller core is powered on via reset_control_deassert(pcie->core_rst). Accessing them before this point results in a CBB timeout because the hardware is not yet operational. Fix this by moving pci_epc_deinit_notify() and dw_pcie_ep_cleanup() to after reset_control_deassert(pcie->core_rst), ensuring the controller is fully powered on before any DBI register accesses occur. Fixes: 40e2125381dc ("PCI: tegra194: Move controller cleanups to pex_ep_event_pex_rst_deassert()") Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Reviewed-by: Vidya Sagar Link: https://patch.msgid.link/20260324190755.1094879-15-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: dwc: Apply ECRC workaround to DesignWare 5.00a as well

2026-05-23T11:04:35+00:00

[ Upstream commit 40805f32dceadebb7381d911003100bec7b8cd51 ] The ECRC (TLP digest) workaround was originally added for DesignWare version 4.90a. Tegra234 SoC has 5.00a DWC HW version, which has the same ATU TD override behaviour, so apply the workaround for 5.00a too. Fixes: a54e19073718 ("PCI: tegra194: Add Tegra234 PCIe support") Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Reviewed-by: Vidya Sagar Link: https://patch.msgid.link/20260324190755.1094879-13-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: tegra194: Use DWC IP core version

2026-05-23T11:04:35+00:00

[ Upstream commit ea60ca067f0f098043610c96a915d162113c1aac ] Tegra194 PCIe driver used custom version numbers to detect Tegra194 and Tegra234 IPs. With version detect logic added, version check results in mismatch warnings: tegra194-pcie 14100000.pcie: Versions don't match (0000562a != 3536322a) Use HW version numbers which match to PORT_LOGIC.PCIE_VERSION_OFF in Tegra194 driver to avoid these kernel warnings. Fixes: a54e19073718 ("PCI: tegra194: Add Tegra234 PCIe support") Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Reviewed-by: Vidya Sagar Link: https://patch.msgid.link/20260324190755.1094879-12-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: tegra194: Free up Endpoint resources during remove()

2026-05-23T11:04:35+00:00

[ Upstream commit 8870f02f7868209eb9bdc5dc53540a6262cf9227 ] Free up the resources during remove() that were acquired by the DesignWare driver for the Endpoint mode during probe(). Fixes: bb617cbd8151 ("PCI: tegra194: Clean up the exit path for Endpoint mode") Signed-off-by: Vidya Sagar Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Reviewed-by: Vidya Sagar Link: https://patch.msgid.link/20260324190755.1094879-11-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: tegra194: Allow system suspend when the Endpoint link is not up

2026-05-23T11:04:35+00:00

[ Upstream commit c76f8eae7d4695b1176c4ea5eb93c17e16a20272 ] Host software initiates the L2 sequence. PCIe link is kept in L2 state during suspend. If Endpoint mode is enabled and the link is up, the software cannot proceed with suspend. However, when the PCIe Endpoint driver is probed, but the PCIe link is not up, Tegra can go into suspend state. So, allow system to suspend in this case. Fixes: de2bbf2b71bb ("PCI: tegra194: Don't allow suspend when Tegra PCIe is in EP mode") Signed-off-by: Vidya Sagar Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Reviewed-by: Vidya Sagar Link: https://patch.msgid.link/20260324190755.1094879-10-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: tegra194: Set LTR message request before PCIe link up in Endpoint mode

2026-05-23T11:04:35+00:00

[ Upstream commit b256493bf8cacf0e524bf4c10b5c4901d0c6cefe ] LTR message should be sent as soon as the Root Port enables LTR in the Endpoint mode. So set snoop and no-snoop LTR timing and LTR message request before the PCIe link comes up, so that the LTR message is sent upstream as soon as LTR is enabled. Without programming these values, the Endpoint would send latencies of 0 to the host, which will be inaccurate. Fixes: c57247f940e8 ("PCI: tegra: Add support for PCIe endpoint mode in Tegra194") Signed-off-by: Vidya Sagar Signed-off-by: Manikanta Maddireddy [mani: commit log] Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Reviewed-by: Jon Hunter Tested-by: Jon Hunter Link: https://patch.msgid.link/20260324190755.1094879-9-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: tegra194: Disable direct speed change for Endpoint mode

2026-05-23T11:04:34+00:00

[ Upstream commit 976f6763f57970388bcd7118931f33f447916927 ] Pre-silicon simulation showed the controller operating in Endpoint mode initiating link speed change after completing Secondary Bus Reset. Ideally, the Root Port or the Switch Downstream Port should initiate the link speed change post SBR, not the Endpoint. So, as per the hardware team recommendation, disable direct speed change for the Endpoint mode to prevent it from initiating speed change after the physical layer link is up at Gen1, leaving speed change ownership with the host. Fixes: c57247f940e8 ("PCI: tegra: Add support for PCIe endpoint mode in Tegra194") Signed-off-by: Vidya Sagar Signed-off-by: Manikanta Maddireddy [mani: commit log] Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Reviewed-by: Vidya Sagar Link: https://patch.msgid.link/20260324190755.1094879-8-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: tegra194: Use devm_gpiod_get_optional() to parse "nvidia,refclk-select"

2026-05-23T11:04:34+00:00

[ Upstream commit f62bc7917de1374dce86a852ffba8baf9cb7a56a ] The GPIO DT property "nvidia,refclk-select", to select the PCIe reference clock is optional. Use devm_gpiod_get_optional() to get it. Fixes: c57247f940e8 ("PCI: tegra: Add support for PCIe endpoint mode in Tegra194") Signed-off-by: Vidya Sagar Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Reviewed-by: Vidya Sagar Link: https://patch.msgid.link/20260324190755.1094879-7-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: tegra194: Disable PERST# IRQ only in Endpoint mode

2026-05-23T11:04:34+00:00

[ Upstream commit 40658a31b6e134169c648041efc84944c4c71dcd ] The PERST# GPIO interrupt is only registered when the controller is operating in Endpoint mode. In Root Port mode, the PERST# GPIO is configured as an output to control downstream devices, and no interrupt is registered for it. Currently, tegra_pcie_dw_stop_link() unconditionally calls disable_irq() on pex_rst_irq, which causes issues in Root Port mode where this IRQ is not registered. Fix this by only disabling the PERST# IRQ when operating in Endpoint mode, where the interrupt is actually registered and used to detect PERST# assertion/deassertion from the host. Fixes: c57247f940e8 ("PCI: tegra: Add support for PCIe endpoint mode in Tegra194") Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Reviewed-by: Vidya Sagar Link: https://patch.msgid.link/20260324190755.1094879-6-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin

PCI: tegra194: Don't force the device into the D0 state before L2

2026-05-23T11:04:34+00:00

[ Upstream commit 71d9f67701e1affc82d18ca88ae798c5361beddf ] As per PCIe CEM r6.0, sec 2.3, the PCIe Endpoint device should be in D3cold to assert WAKE# pin. The previous workaround that forced downstream devices to D0 before taking the link to L2 cited PCIe r4.0, sec 5.2, "Link State Power Management"; however, that spec does not explicitly require putting the device into D0 and only indicates that power removal may be initiated without transitioning to D3hot. Remove the D0 workaround so that Endpoint devices can use wake functionality (WAKE# from D3). With some Endpoints the link may not enter L2 when they remain in D3, but the Root Port continues with the usual flow after PME timeout, so there is no functional issue. Fixes: 56e15a238d92 ("PCI: tegra: Add Tegra194 PCIe support") Signed-off-by: Vidya Sagar Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Vidya Sagar Reviewed-by: Jon Hunter Link: https://patch.msgid.link/20260324190755.1094879-5-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin