kernel.git/drivers/pci/probe.c, branch linux-6.15.y

PCI/ACPI: Fix runtime PM ref imbalance on Hot-Plug Capable ports

2025-08-20T16:35:46Z

commit 6cff20ce3b92ffbf2fc5eb9e5a030b3672aa414a upstream. pci_bridge_d3_possible() is called from both pcie_portdrv_probe() and pcie_portdrv_remove() to determine whether runtime power management shall be enabled (on probe) or disabled (on remove) on a PCIe port. The underlying assumption is that pci_bridge_d3_possible() always returns the same value, else a runtime PM reference imbalance would occur. That assumption is not given if the PCIe port is inaccessible on remove due to hot-unplug: pci_bridge_d3_possible() calls pciehp_is_native(), which accesses Config Space to determine whether the port is Hot-Plug Capable. An inaccessible port returns "all ones", which is converted to "all zeroes" by pcie_capability_read_dword(). Hence the port no longer seems Hot-Plug Capable on remove even though it was on probe. The resulting runtime PM ref imbalance causes warning messages such as: pcieport 0000:02:04.0: Runtime PM usage count underflow! Avoid the Config Space access (and thus the runtime PM ref imbalance) by caching the Hot-Plug Capable bit in struct pci_dev. The struct already contains an "is_hotplug_bridge" flag, which however is not only set on Hot-Plug Capable PCIe ports, but also Conventional PCI Hot-Plug bridges and ACPI slots. The flag identifies bridges which are allocated additional MMIO and bus number resources to allow for hierarchy expansion. The kernel is somewhat sloppily using "is_hotplug_bridge" in a number of places to identify Hot-Plug Capable PCIe ports, even though the flag encompasses other devices. Subsequent commits replace these occurrences with the new flag to clearly delineate Hot-Plug Capable PCIe ports from other kinds of hotplug bridges. Document the existing "is_hotplug_bridge" and the new "is_pciehp" flag and document the (non-obvious) requirement that pci_bridge_d3_possible() always returns the same value across the entire lifetime of a bridge, including its hot-removal. Fixes: 5352a44a561d ("PCI: pciehp: Make pciehp_is_native() stricter") Reported-by: Laurent Bigonville Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220216 Reported-by: Mario Limonciello Closes: https://lore.kernel.org/r/20250609020223.269407-3-superm1@kernel.org/ Link: https://lore.kernel.org/all/20250620025535.3425049-3-superm1@kernel.org/T/#u Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Acked-by: Rafael J. Wysocki Cc: stable@vger.kernel.org # v4.18+ Link: https://patch.msgid.link/fe5dcc3b2e62ee1df7905d746bde161eb1b3291c.1752390101.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman

PCI/pwrctrl: Create pwrctrl devices only when CONFIG_PCI_PWRCTRL is enabled

2025-08-01T08:51:27Z

commit 8c493cc91f3a1102ad2f8c75ae0cf80f0a057488 upstream. If devicetree describes power supplies related to a PCI device, we unnecessarily created a pwrctrl device even if CONFIG_PCI_PWRCTL was not enabled. We only need pci_pwrctrl_create_device() when CONFIG_PCI_PWRCTRL is enabled. Compile it out when CONFIG_PCI_PWRCTRL is not enabled. When pci_pwrctrl_create_device() creates and returns a pwrctrl device, pci_scan_device() doesn't enumerate the PCI device. It assumes the pwrctrl core will rescan the bus after turning on the power. However, if CONFIG_PCI_PWRCTRL is not enabled, the rescan never happens, which breaks PCI enumeration on any system that describes power supplies in devicetree but does not use pwrctrl. Jim reported that some brcmstb platforms break this way. The brcmstb driver is still broken if CONFIG_PCI_PWRCTRL is enabled, but this commit at least allows brcmstb to work when it's NOT enabled. Fixes: 957f40d039a9 ("PCI/pwrctrl: Move creation of pwrctrl devices to pci_scan_device()") Reported-by: Jim Quinlan Link: https://lore.kernel.org/r/CA+-6iNwgaByXEYD3j=-+H_PKAxXRU78svPMRHDKKci8AGXAUPg@mail.gmail.com Signed-off-by: Manivannan Sadhasivam [bhelgaas: commit log] Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner Cc: stable@vger.kernel.org # v6.15 Link: https://patch.msgid.link/20250701064731.52901-1-manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman

Merge tag 'pci-v6.15-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci

2025-03-29T02:36:53Z

Pull pci updates from Bjorn Helgaas: "Enumeration: - Enable Configuration RRS SV, which makes device readiness visible, early instead of during child bus scanning (Bjorn Helgaas) - Log debug messages about reset methods being used (Bjorn Helgaas) - Avoid reset when it has been disabled via sysfs (Nishanth Aravamudan) - Add common pci-ep-bus.yaml schema for exporting several peripherals of a single PCI function via devicetree (Andrea della Porta) - Create DT nodes for PCI host bridges to enable loading device tree overlays to create platform devices for PCI devices that have several features that require multiple drivers (Herve Codina) Resource management: - Enlarge devres table[] to accommodate bridge windows, ROM, IOV BARs, etc., and validate BAR index in devres interfaces (Philipp Stanner) - Fix typo that repeatedly distributed resources to a bridge instead of iterating over subordinate bridges, which resulted in too little space to assign some BARs (Kai-Heng Feng) - Relax bridge window tail sizing for optional resources, e.g., IOV BARs, to avoid failures when removing and re-adding devices (Ilpo Järvinen) - Allow drivers to enable devices even if we haven't assigned optional IOV resources to them (Ilpo Järvinen) - Rework handling of optional resources (IOV BARs, ROMs) to reduce failures if we can't allocate them (Ilpo Järvinen) - Fix a NULL dereference in the SR-IOV VF creation error path (Shay Drory) - Fix s390 mmio_read/write syscalls, which didn't cause page faults in some cases, which broke vfio-pci lazy mapping on first access (Niklas Schnelle) - Add pdev->non_mappable_bars to replace CONFIG_VFIO_PCI_MMAP, which was disabled only for s390 (Niklas Schnelle) - Support mmap of PCI resources on s390 except for ISM devices (Niklas Schnelle) ASPM: - Delay pcie_link_state deallocation to avoid dangling pointers that cause invalid references during hot-unplug (Daniel Stodden) Power management: - Allow PCI bridges to go to D3Hot when suspending on all non-x86 systems (Manivannan Sadhasivam) Power control: - Create pwrctrl devices in pci_scan_device() to make it more symmetric with pci_pwrctrl_unregister() and make pwrctrl devices for PCI bridges possible (Manivannan Sadhasivam) - Unregister pwrctrl devices in pci_destroy_dev() so DOE, ASPM, etc. can still access devices after pci_stop_dev() (Manivannan Sadhasivam) - If there's a pwrctrl device for a PCI device, skip scanning it because the pwrctrl core will rescan the bus after the device is powered on (Manivannan Sadhasivam) - Add a pwrctrl driver for PCI slots based on voltage regulators described via devicetree (Manivannan Sadhasivam) Bandwidth control: - Add set_pcie_speed.sh to TEST_PROGS to fix issue when executing the set_pcie_cooling_state.sh test case (Yi Lai) - Avoid a NULL pointer dereference when we run out of bus numbers to assign for a bridge secondary bus (Lukas Wunner) Hotplug: - Drop superfluous pci_hotplug_slot_list, try_module_get() calls, and NULL pointer checks (Lukas Wunner) - Drop shpchp module init/exit logging, replace shpchp dbg() with ctrl_dbg(), and remove unused dbg(), err(), info(), warn() wrappers (Ilpo Järvinen) - Drop 'shpchp_debug' module parameter in favor of standard dynamic debugging (Ilpo Järvinen) - Drop unused cpcihp .get_power(), .set_power() function pointers (Guilherme Giacomo Simoes) - Disable hotplug interrupts in portdrv only when pciehp is not enabled to avoid issuing two hotplug commands too close together (Feng Tang) - Skip pciehp 'device replaced' check if the device has been removed to address a deadlock when resuming after a device was removed during system sleep (Lukas Wunner) - Don't enable pciehp hotplug interupt when resuming in poll mode (Ilpo Järvinen) Virtualization: - Fix bugs in 'pci=config_acs=' kernel command line parameter (Tushar Dave) DOE: - Expose supported DOE features via sysfs (Alistair Francis) - Allow DOE support to be enabled even if CXL isn't enabled (Alistair Francis) Endpoint framework: - Convert PCI device data so pci-epf-test works correctly on big-endian endpoint systems (Niklas Cassel) - Add BAR_RESIZABLE type to endpoint framework and add DWC core support for EPF drivers to set BAR_RESIZABLE type and size (Niklas Cassel) - Fix pci-epf-test double free that causes an oops if the host reboots and PERST# deassertion restarts endpoint BAR allocation (Christian Bruel) - Fix endpoint BAR testing so tests can skip disabled BARs instead of reporting them as failures (Niklas Cassel) - Widen endpoint test BAR size variable to accommodate BARs larger than INT_MAX (Niklas Cassel) - Remove unused tools 'pci' build target left over after moving tests to tools/testing/selftests/pci_endpoint (Jianfeng Liu) Altera PCIe controller driver: - Add DT binding and driver support for Agilex family (P-Tile, F-Tile, R-Tile) (Matthew Gerlach and D M, Sharath Kumar) AMD MDB PCIe controller driver: - Add DT binding and driver for AMD MDB (Multimedia DMA Bridge) (Thippeswamy Havalige) Broadcom STB PCIe controller driver: - Add BCM2712 MSI-X DT binding and interrupt controller drivers and add softdep on irq_bcm2712_mip driver to ensure that it is loaded first (Stanimir Varbanov) - Expand inbound window map to 64GB so it can accommodate BCM2712 (Stanimir Varbanov) - Add BCM2712 support and DT updates (Stanimir Varbanov) - Apply link speed restriction before bringing link up, not after (Jim Quinlan) - Update Max Link Speed in Link Capabilities via the internal writable register, not the read-only config register (Jim Quinlan) - Handle regulator_bulk_get() error to avoid panic when we call regulator_bulk_free() later (Jim Quinlan) - Disable regulators only when removing the bus immediately below a Root Port because we don't support regulators deeper in the hierarchy (Jim Quinlan) - Make const read-only arrays static (Colin Ian King) Cadence PCIe endpoint driver: - Correct MSG TLP generation so endpoints can generate INTx messages (Hans Zhang) Freescale i.MX6 PCIe controller driver: - Identify the second controller on i.MX8MQ based on devicetree 'linux,pci-domain' instead of DBI 'reg' address (Richard Zhu) - Remove imx_pcie_cpu_addr_fixup() since dwc core can now derive the ATU input address (using parent_bus_offset) from devicetree (Frank Li) Freescale Layerscape PCIe controller driver: - Drop deprecated 'num-ib-windows' and 'num-ob-windows' and unnecessary 'status' from example (Krzysztof Kozlowski) - Correct the syscon_regmap_lookup_by_phandle_args("fsl,pcie-scfg") arg_count to fix probe failure on LS1043A (Ioana Ciornei) HiSilicon STB PCIe controller driver: - Call phy_exit() to clean up if histb_pcie_probe() fails (Christophe JAILLET) Intel Gateway PCIe controller driver: - Remove intel_pcie_cpu_addr() since dwc core can now derive the ATU input address (using parent_bus_offset) from devicetree (Frank Li) Intel VMD host bridge driver: - Convert vmd_dev.cfg_lock from spinlock_t to raw_spinlock_t so pci_ops.read() will never sleep, even on PREEMPT_RT where spinlock_t becomes a sleepable lock, to avoid calling a sleeping function from invalid context (Ryo Takakura) MediaTek PCIe Gen3 controller driver: - Remove leftover mac_reset assert for Airoha EN7581 SoC (Lorenzo Bianconi) - Add EN7581 PBUS controller 'mediatek,pbus-csr' DT property and program host bridge memory aperture to this syscon node (Lorenzo Bianconi) Qualcomm PCIe controller driver: - Add qcom,pcie-ipq5332 binding (Varadarajan Narayanan) - Add qcom i.MX8QM and i.MX8QXP/DXP optional DMA interrupt (Alexander Stein) - Add optional dma-coherent DT property for Qualcomm SA8775P (Dmitry Baryshkov) - Make DT iommu property required for SA8775P and prohibited for SDX55 (Dmitry Baryshkov) - Add DT IOMMU and DMA-related properties for Qualcomm SM8450 (Dmitry Baryshkov) - Add endpoint DT properties for SAR2130P and enable endpoint mode in driver (Dmitry Baryshkov) - Describe endpoint BAR0 and BAR2 as 64-bit only and BAR1 and BAR3 as RESERVED (Manivannan Sadhasivam) Rockchip DesignWare PCIe controller driver: - Describe rk3568 and rk3588 BARs as Resizable, not Fixed (Niklas Cassel) Synopsys DesignWare PCIe controller driver: - Add debugfs-based Silicon Debug, Error Injection, Statistical Counter support for DWC (Shradha Todi) - Add debugfs property to expose LTSSM status of DWC PCIe link (Hans Zhang) - Add Rockchip support for DWC debugfs features (Niklas Cassel) - Add dw_pcie_parent_bus_offset() to look up the parent bus address of a specified 'reg' property and return the offset from the CPU physical address (Frank Li) - Use dw_pcie_parent_bus_offset() to derive CPU -> ATU addr offset via 'reg[config]' for host controllers and 'reg[addr_space]' for endpoint controllers (Frank Li) - Apply struct dw_pcie.parent_bus_offset in ATU users to remove use of .cpu_addr_fixup() when programming ATU (Frank Li) TI J721E PCIe driver: - Correct the 'link down' interrupt bit for J784S4 (Siddharth Vadapalli) TI Keystone PCIe controller driver: - Describe AM65x BARs 2 and 5 as Resizable (not Fixed) and reduce alignment requirement from 1MB to 64KB (Niklas Cassel) Xilinx Versal CPM PCIe controller driver: - Free IRQ domain in probe error path to avoid leaking it (Thippeswamy Havalige) - Add DT .compatible "xlnx,versal-cpm5nc-host" and driver support for Versal Net CPM5NC Root Port controller (Thippeswamy Havalige) - Add driver support for CPM5_HOST1 (Thippeswamy Havalige) Miscellaneous: - Convert fsl,mpc83xx-pcie binding to YAML (J. Neuschäfer) - Use for_each_available_child_of_node_scoped() to simplify apple, kirin, mediatek, mt7621, tegra drivers (Zhang Zekun)" * tag 'pci-v6.15-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (197 commits) PCI: layerscape: Fix arg_count to syscon_regmap_lookup_by_phandle_args() PCI: j721e: Fix the value of .linkdown_irq_regfield for J784S4 misc: pci_endpoint_test: Add support for PCITEST_IRQ_TYPE_AUTO PCI: endpoint: pci-epf-test: Expose supported IRQ types in CAPS register PCI: dw-rockchip: Endpoint mode cannot raise INTx interrupts PCI: endpoint: Add intx_capable to epc_features struct dt-bindings: PCI: Add common schema for devices accessible through PCI BARs PCI: intel-gw: Remove intel_pcie_cpu_addr() PCI: imx6: Remove imx_pcie_cpu_addr_fixup() PCI: dwc: Use parent_bus_offset to remove need for .cpu_addr_fixup() PCI: dwc: ep: Ensure proper iteration over outbound map windows PCI: dwc: ep: Use devicetree 'reg[addr_space]' to derive CPU -> ATU addr offset PCI: dwc: ep: Consolidate devicetree handling in dw_pcie_ep_get_resources() PCI: dwc: ep: Call epc_create() early in dw_pcie_ep_init() PCI: dwc: Use devicetree 'reg[config]' to derive CPU -> ATU addr offset PCI: dwc: Add dw_pcie_parent_bus_offset() checking and debug PCI: dwc: Add dw_pcie_parent_bus_offset() PCI/bwctrl: Fix NULL pointer dereference on bus number exhaustion PCI: xilinx-cpm: Add cpm_csr register mapping for CPM5_HOST1 variant PCI: brcmstb: Make const read-only arrays static ...

Merge branch 'pci/devtree-create'

2025-03-27T18:14:45Z

- Add device_add_of_node() to set dev->of_node and dev->fwnode only if they haven't been set already (Herve Codina) - Allow of_pci_set_address() to set the DT address property for root bus nodes, where there is no PCI bridge to supply the PCI bus/device/function part of the property (Herve Codina) - Create DT nodes for PCI host bridges to enable loading device tree overlays to create platform devices for PCI devices that have several features that require multiple drivers (Herve Codina) * pci/devtree-create: PCI: of: Create device tree PCI host bridge node PCI: of_property: Constify parameter in of_pci_get_addr_flags() PCI: of_property: Add support for NULL pdev in of_pci_set_address() PCI: of: Use device_{add,remove}_of_node() to attach of_node to existing device driver core: Introduce device_{add,remove}_of_node()

Merge branch 'pci/pwrctrl'

2025-03-27T18:14:44Z

- Create pwrctrl devices in pci_scan_device() to make it more symmetric with pci_pwrctrl_unregister() and make pwrctrl devices for PCI bridges possible (Manivannan Sadhasivam) - Unregister pwrctrl devices in pci_destroy_dev() so DOE, ASPM, etc. can still access devices after pci_stop_dev() (Manivannan Sadhasivam) - If there's a pwrctrl device for a PCI device, skip scanning it because the pwrctrl core will rescan the bus after the device is powered on (Manivannan Sadhasivam) - Add a pwrctrl driver for PCI slots based on voltage regulators described via devicetree (Manivannan Sadhasivam) * pci/pwrctrl: PCI/pwrctrl: Add pwrctrl driver for PCI slots dt-bindings: vendor-prefixes: Document the 'pciclass' prefix PCI/pwrctrl: Skip scanning for the device further if pwrctrl device is created PCI/pwrctrl: Move pci_pwrctrl_unregister() to pci_destroy_dev() PCI/pwrctrl: Move creation of pwrctrl devices to pci_scan_device()

Merge branch 'pci/enumeration'

2025-03-27T18:14:43Z

- Enable Configuration RRS SV early instead of during child bus scanning (Bjorn Helgaas) - Cache offset of Resizable BAR capability to avoid redundant searches for it (Bjorn Helgaas) - Fix reference leaks in pci_register_host_bridge() and pci_alloc_child_bus() (Ma Ke) - Drop put_device() in pci_register_host_bridge() left over from converting device_register() to device_add() (Dan Carpenter) * pci/enumeration: PCI: Remove stray put_device() in pci_register_host_bridge() PCI: Fix reference leak in pci_alloc_child_bus() PCI: Fix reference leak in pci_register_host_bridge() PCI: Cache offset of Resizable BAR capability PCI: Enable Configuration RRS SV early

Merge branch 'pci/doe'

2025-03-27T18:14:43Z

- Rename DOE 'protocol' to 'feature' to follow spec terminology (Alistair Francis) - Expose supported DOE features via sysfs (Alistair Francis) - Allow DOE support to be enabled even if CXL isn't enabled (Alistair Francis) * pci/doe: PCI/DOE: Allow enabling DOE without CXL PCI/DOE: Expose DOE features via sysfs PCI/DOE: Rename Discovery Response Data Object Contents to type PCI/DOE: Rename DOE protocol to feature

PCI/DOE: Expose DOE features via sysfs

2025-03-21T21:36:01Z

PCIe r6.0 added support for Data Object Exchange (DOE). When DOE is supported, the DOE Discovery Feature must be implemented per PCIe r6.1, sec 6.30.1.1. DOE allows a requester to obtain information about the other DOE features supported by the device. The kernel already queries the DOE features supported and caches the values. Expose the values in sysfs to allow user space to determine which DOE features are supported by the PCIe device. By exposing the information to userspace, tools like lspci can relay the information to users. By listing all of the supported features we can allow userspace to parse the list, which might include vendor specific features as well as yet to be supported features. As the DOE Discovery feature must always be supported we treat it as a special named attribute case. This allows the usual PCI attribute_group handling to correctly create the doe_features directory when registering pci_doe_sysfs_group (otherwise it doesn't and sysfs_add_file_to_group() will seg fault). After this patch is supported you can see something like this when attaching a DOE device: $ ls /sys/devices/pci0000:00/0000:00:02.0//doe* 0001:01 0001:02 doe_discovery Link: https://lore.kernel.org/r/20250306075211.1855177-3-alistair@alistair23.me Signed-off-by: Alistair Francis [bhelgaas: drop pci_doe_sysfs_init() stub return, make DEVICE_ATTR_RO(doe_discovery) static] Signed-off-by: Bjorn Helgaas Reviewed-by: Jonathan Cameron

PCI: Remove stray put_device() in pci_register_host_bridge()

2025-03-10T18:41:48Z

This put_device() was accidentally left over from when we changed the code from using device_register() to calling device_add(). Delete it. Link: https://lore.kernel.org/r/55b24870-89fb-4c91-b85d-744e35db53c2@stanley.mountain Fixes: 9885440b16b8 ("PCI: Fix pci_host_bridge struct device release/free handling") Signed-off-by: Dan Carpenter Signed-off-by: Bjorn Helgaas

PCI: Fix reference leak in pci_alloc_child_bus()

2025-03-10T18:41:48Z

If device_register(&child->dev) fails, call put_device() to explicitly release child->dev, per the comment at device_register(). Found by code review. Link: https://lore.kernel.org/r/20250202062357.872971-1-make24@iscas.ac.cn Fixes: 4f535093cf8f ("PCI: Put pci_dev in device tree as early as possible") Signed-off-by: Ma Ke Signed-off-by: Bjorn Helgaas Reviewed-by: Ilpo Järvinen Cc: stable@vger.kernel.org