kernel/drivers/pci/controller/dwc/pcie-qcom.c, branch linux-6.18.y

PCI: dwc: Advertise L1 PM Substates only if driver requests it

2026-03-12T11:09:24Z

[ Upstream commit a00bba406b5a682764ecb507e580ca8159196aa3 ] L1 PM Substates require the CLKREQ# signal and may also require device-specific support. If CLKREQ# is not supported or driver support is lacking, enabling L1.1 or L1.2 may cause errors when accessing devices, e.g., nvme nvme0: controller is down; will reset: CSTS=0xffffffff, PCI_STATUS=0x10 If the kernel is built with CONFIG_PCIEASPM_POWER_SUPERSAVE=y or users enable L1.x via sysfs, users may trip over these errors even if L1 Substates haven't been enabled by firmware or the driver. To prevent such errors, disable advertising the L1 PM Substates unless the driver sets "dw_pcie.l1ss_support" to indicate that it knows CLKREQ# is present and any device-specific configuration has been done. Set "dw_pcie.l1ss_support" in tegra194 (if DT includes the "supports-clkreq' property) and qcom (for cfg_2_7_0, cfg_1_9_0, cfg_1_34_0, and cfg_sc8280xp controllers) so they can continue to use L1 Substates. Based on Niklas's patch: https://patch.msgid.link/20251017163252.598812-2-cassel@kernel.org [bhelgaas: drop hiding for endpoints] Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20251118214312.2598220-2-helgaas@kernel.org Stable-dep-of: 180c3cfe3678 ("Revert "PCI: dw-rockchip: Enumerate endpoints based on dll_link_up IRQ"") Signed-off-by: Sasha Levin

Revert "PCI: qcom: Enumerate endpoints based on Link up event in 'global_irq' interrupt"

2026-03-04T12:20:55Z

[ Upstream commit 9a9793b55854422652ea92625e48277c4651c0fd ] This reverts commit 4581403f67929d02c197cb187c4e1e811c9e762a. While this fake hotplugging was a nice idea, it has shown that this feature does not handle PCIe switches correctly: pci_bus 0004:43: busn_res: can not insert [bus 43-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:43: busn_res: [bus 43-41] end is updated to 43 pci_bus 0004:43: busn_res: can not insert [bus 43] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:00.0: devices behind bridge are unusable because [bus 43] cannot be assigned for them pci_bus 0004:44: busn_res: can not insert [bus 44-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:44: busn_res: [bus 44-41] end is updated to 44 pci_bus 0004:44: busn_res: can not insert [bus 44] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:02.0: devices behind bridge are unusable because [bus 44] cannot be assigned for them pci_bus 0004:45: busn_res: can not insert [bus 45-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:45: busn_res: [bus 45-41] end is updated to 45 pci_bus 0004:45: busn_res: can not insert [bus 45] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:06.0: devices behind bridge are unusable because [bus 45] cannot be assigned for them pci_bus 0004:46: busn_res: can not insert [bus 46-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:46: busn_res: [bus 46-41] end is updated to 46 pci_bus 0004:46: busn_res: can not insert [bus 46] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:0e.0: devices behind bridge are unusable because [bus 46] cannot be assigned for them pci_bus 0004:42: busn_res: [bus 42-41] end is updated to 46 pci_bus 0004:42: busn_res: can not insert [bus 42-46] under [bus 41] (conflicts with (null) [bus 41]) pci 0004:41:00.0: devices behind bridge are unusable because [bus 42-46] cannot be assigned for them pcieport 0004:40:00.0: bridge has subordinate 41 but max busn 46 During the initial scan, PCI core doesn't see the switch and since the Root Port is not hot plug capable, the secondary bus number gets assigned as the subordinate bus number. This means, the PCI core assumes that only one bus will appear behind the Root Port since the Root Port is not hot plug capable. This works perfectly fine for PCIe endpoints connected to the Root Port, since they don't extend the bus. However, if a PCIe switch is connected, then there is a problem when the downstream busses starts showing up and the PCI core doesn't extend the subordinate bus number and bridge resources after initial scan during boot. The long term plan is to migrate this driver to the upcoming pwrctrl APIs that are supposed to handle this problem elegantly. Suggested-by: Manivannan Sadhasivam Signed-off-by: Niklas Cassel Signed-off-by: Manivannan Sadhasivam Tested-by: Shawn Lin Acked-by: Shawn Lin Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20251222064207.3246632-13-cassel@kernel.org Signed-off-by: Sasha Levin

Revert "PCI: qcom: Enable MSI interrupts together with Link up if 'Global IRQ' is supported"

2026-03-04T12:20:55Z

[ Upstream commit 7ebdefb87942073679e56cfbc5a72e8fc5441bfc ] This reverts commit ba4a2e2317b9faeca9193ed6d3193ddc3cf2aba3. Since the Link up IRQ support is going away, revert the MSI logic that got added for it too. Suggested-by: Manivannan Sadhasivam Signed-off-by: Niklas Cassel [mani: reworded the description] Signed-off-by: Manivannan Sadhasivam Tested-by: Shawn Lin Acked-by: Shawn Lin Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20251222064207.3246632-12-cassel@kernel.org Signed-off-by: Sasha Levin

Revert "PCI: qcom: Don't wait for link if we can detect Link Up"

2026-03-04T12:20:55Z

[ Upstream commit e9ce5b3804436301ab343bc14203a4c14b336d1b ] This reverts commit 36971d6c5a9a134c15760ae9fd13c6d5f9a36abb. While this fake hotplugging was a nice idea, it has shown that this feature does not handle PCIe switches correctly: pci_bus 0004:43: busn_res: can not insert [bus 43-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:43: busn_res: [bus 43-41] end is updated to 43 pci_bus 0004:43: busn_res: can not insert [bus 43] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:00.0: devices behind bridge are unusable because [bus 43] cannot be assigned for them pci_bus 0004:44: busn_res: can not insert [bus 44-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:44: busn_res: [bus 44-41] end is updated to 44 pci_bus 0004:44: busn_res: can not insert [bus 44] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:02.0: devices behind bridge are unusable because [bus 44] cannot be assigned for them pci_bus 0004:45: busn_res: can not insert [bus 45-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:45: busn_res: [bus 45-41] end is updated to 45 pci_bus 0004:45: busn_res: can not insert [bus 45] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:06.0: devices behind bridge are unusable because [bus 45] cannot be assigned for them pci_bus 0004:46: busn_res: can not insert [bus 46-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:46: busn_res: [bus 46-41] end is updated to 46 pci_bus 0004:46: busn_res: can not insert [bus 46] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:0e.0: devices behind bridge are unusable because [bus 46] cannot be assigned for them pci_bus 0004:42: busn_res: [bus 42-41] end is updated to 46 pci_bus 0004:42: busn_res: can not insert [bus 42-46] under [bus 41] (conflicts with (null) [bus 41]) pci 0004:41:00.0: devices behind bridge are unusable because [bus 42-46] cannot be assigned for them pcieport 0004:40:00.0: bridge has subordinate 41 but max busn 46 During the initial scan, PCI core doesn't see the switch and since the Root Port is not hot plug capable, the secondary bus number gets assigned as the subordinate bus number. This means, the PCI core assumes that only one bus will appear behind the Root Port since the Root Port is not hot plug capable. This works perfectly fine for PCIe endpoints connected to the Root Port, since they don't extend the bus. However, if a PCIe switch is connected, then there is a problem when the downstream busses starts showing up and the PCI core doesn't extend the subordinate bus number and bridge resources after initial scan during boot. The long term plan is to migrate this driver to the upcoming pwrctrl APIs that are supposed to handle this problem elegantly. Suggested-by: Manivannan Sadhasivam Signed-off-by: Niklas Cassel Signed-off-by: Manivannan Sadhasivam Tested-by: Shawn Lin Acked-by: Shawn Lin Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20251222064207.3246632-11-cassel@kernel.org Signed-off-by: Sasha Levin

PCI: qcom: Remove ASPM L0s support for MSM8996 SoC

2026-02-11T12:41:49Z

[ Upstream commit 0cc13256b60510936c34098ee7b929098eed823b ] Though I couldn't confirm ASPM L0s support with the Qcom hardware team, a bug report from Dmitry suggests that L0s is broken on this legacy SoC. Hence, remove L0s support from the Root Port Link Capabilities in this SoC. Since qcom_pcie_clear_aspm_l0s() is now used by more than one SoC config, call it from qcom_pcie_host_init() instead. Reported-by: Dmitry Baryshkov Closes: https://lore.kernel.org/linux-pci/4cp5pzmlkkht2ni7us6p3edidnk25l45xrp6w3fxguqcvhq2id@wjqqrdpkypkf Signed-off-by: Manivannan Sadhasivam Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Dmitry Baryshkov Reviewed-by: Konrad Dybcio Link: https://patch.msgid.link/20251126081718.8239-1-mani@kernel.org Signed-off-by: Sasha Levin

Merge tag 'pci-v6.18-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci

2025-10-31T21:24:32Z

Pull pci fixes from Bjorn Helgaas: - Restore custom qcom ASPM enablement code so L1 PM Substates are enabled as they were in v6.17 even though the PCI core now enables just L0s and L1 by default (Bjorn Helgaas) - Size prefetchable bridge windows only when they actually exist, to avoid a WARN_ON() regression (Ilpo Järvinen) * tag 'pci-v6.18-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: PCI: Do not size non-existing prefetchable window Revert "PCI: qcom: Remove custom ASPM enablement code"

Revert "PCI: qcom: Remove custom ASPM enablement code"

2025-10-31T20:04:19Z

This reverts commit a729c16646198872e345bf6c48dbe540ad8a9753. Prior to a729c1664619 ("PCI: qcom: Remove custom ASPM enablement code"), the qcom controller driver enabled ASPM, including L0s, L1, and L1 PM Substates, for all devices powered on at the time the controller driver enumerates them. ASPM was *not* enabled for devices powered on later by pwrctrl (unless the kernel was built with PCIEASPM_POWERSAVE or PCIEASPM_POWER_SUPERSAVE, or the user enabled ASPM via module parameter or sysfs). After f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devicetree platforms"), the PCI core enabled all ASPM states for all devices whether powered on initially or by pwrctrl, so a729c1664619 was unnecessary and reverted. But f3ac2ff14834 was too aggressive and broke platforms that didn't support CLKREQ# or required device-specific configuration for L1 Substates, so df5192d9bb0e ("PCI/ASPM: Enable only L0s and L1 for devicetree platforms") enabled only L0s and L1. On Qualcomm platforms, this left L1 Substates disabled, which was a regression. Revert a729c1664619 so L1 Substates will be enabled on devices that are initially powered on. Devices powered on by pwrctrl will be addressed later. Fixes: df5192d9bb0e ("PCI/ASPM: Enable only L0s and L1 for devicetree platforms") Reported-by: Johan Hovold Closes: https://lore.kernel.org/lkml/aPuXZlaawFmmsLmX@hovoldconsulting.com/ Signed-off-by: Bjorn Helgaas Tested-by: Johan Hovold Reviewed-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20251024210514.1365996-1-helgaas@kernel.org

Revert "PCI: qcom: Prepare for the DWC ECAM enablement"

2025-10-20T15:31:54Z

This reverts commit 4660e50cf81800f82eeecf743ad1e3e97ab72190. Commit f6fd357f7afb ("PCI: dwc: Prepare the driver for enabling ECAM mechanism using iATU 'CFG Shift Feature'") enabled ECAM access by using the config space start as DBI address. However, this approach breaks vendor drivers that rely on the DBI address for internal accesses, especially when the vendor config space is 256MB aligned. To resolve this, avoid using the DBI as the start of config space and instead introduce a custom ECAM PCI ops implementation. Revert the qcom specific ECAM preparation logic in 4660e50cf818 ("PCI: qcom: Prepare for the DWC ECAM enablement") since it's no longer necessary. Signed-off-by: Krishna Chaitanya Chundru [bhelgaas: commit log] Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20251017-ecam_fix-v1-2-f6faa3d0edf3@oss.qualcomm.com

Merge branch 'pci/controller/qcom'

2025-10-03T17:13:20Z

- Select PCI Power Control Slot driver so slot voltage rails can be turned on/off if described in Root Port device tree node (Qiang Yu) - Parse only PCI bridge child nodes in device tree, skipping unrelated nodes such as OPP (Operating Performance Points), which caused probe failures (Krishna Chaitanya Chundru) - Add 8.0 GT/s and 32.0 GT/s equalization settings (Ziyue Zhang) - Fix typo in CURSOR macro names (Ziyue Zhang) - Consolidate Root Port 'phy' and 'reset' properties in struct qcom_pcie_port, regardless of whether we got them from the Root Port node or the host bridge node (Manivannan Sadhasivam) - Fetch and map the ELBI register space in the DWC core rather than in each driver individually (Krishna Chaitanya Chundru) - Enable ECAM mechanism in DWC core by setting up iATU with 'CFG Shift Feature' and use this in the qcom driver (Krishna Chaitanya Chundru) * pci/controller/qcom: PCI: dwc: Support ECAM mechanism by enabling iATU 'CFG Shift Feature' PCI: qcom: Prepare for the DWC ECAM enablement PCI: dwc: Prepare the driver for enabling ECAM mechanism using iATU 'CFG Shift Feature' PCI: dwc: Add support for ELBI resource mapping PCI: qcom: Move host bridge 'phy' and 'reset' pointers to struct qcom_pcie_port PCI: qcom: Fix macro typo for CURSOR PCI: qcom: Add equalization settings for 8.0 GT/s and 32.0 GT/s PCI: qcom: Restrict port parsing only to PCIe bridge child nodes PCI: qcom: Select PCI Power Control Slot driver

PCI: qcom: Prepare for the DWC ECAM enablement

2025-09-25T13:03:56Z

To support the DWC ECAM mechanism, prepare the driver by performing below configurations: 1. Since the ELBI region will be covered by the ECAM 'config' space, override the 'elbi_base' with the address derived from 'dbi_base' and the offset from PARF_SLV_DBI_ELBI register. 2. Block the transactions from the host bridge to devices other than Root Port on the root bus to return all F's. This is required when the 'CFG Shift Feature' of iATU is enabled. Signed-off-by: Krishna Chaitanya Chundru [mani: code split, reworded subject/description and comments] Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20250923-controller-dwc-ecam-v10-3-e84390ba75fa@kernel.org