kernel/linux.git/Documentation/PCI, branch v6.18.21

Documentation: PCI: endpoint: Fix ntb/vntb copy & paste errors

2026-02-26T22:59:15+00:00

[ Upstream commit ad0c6da5be901f5c181490f683d22b416059bccb ] Fix copy & paste errors by changing the references from 'ntb' to 'vntb'. Fixes: 4ac8c8e52cd9 ("Documentation: PCI: Add specification for the PCI vNTB function device") Signed-off-by: Baruch Siach [mani: squashed the patches and fixed more errors] Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Reviewed-by: Frank Li Link: https://patch.msgid.link/b51c2a69ffdbfa2c359f5cf33f3ad2acc3db87e4.1762154911.git.baruch@tkos.co.il Signed-off-by: Sasha Levin

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

2025-10-06T17:41:03+00:00

Pull pci updates from Bjorn Helgaas: "Enumeration: - Add PCI_FIND_NEXT_CAP() and PCI_FIND_NEXT_EXT_CAP() macros that take config space accessor functions. Implement pci_find_capability(), pci_find_ext_capability(), and dwc, dwc endpoint, and cadence capability search interfaces with them (Hans Zhang) - Leave parent unit address 0 in 'interrupt-map' so that when we build devicetree nodes to describe PCI functions that contain multiple peripherals, we can build this property even when interrupt controllers lack 'reg' properties (Lorenzo Pieralisi) - Add a Xeon 6 quirk to disable Extended Tags and limit Max Read Request Size to 128B to avoid a performance issue (Ilpo Järvinen) - Add sysfs 'serial_number' file to expose the Device Serial Number (Matthew Wood) - Fix pci_acpi_preserve_config() memory leak (Nirmoy Das) Resource management: - Align m68k pcibios_enable_device() with other arches (Ilpo Järvinen) - Remove sparc pcibios_enable_device() implementations that don't do anything beyond what pci_enable_resources() does (Ilpo Järvinen) - Remove mips pcibios_enable_resources() and use pci_enable_resources() instead (Ilpo Järvinen) - Clean up bridge window sizing and assignment (Ilpo Järvinen), including: - Leave non-claimed bridge windows disabled - Enable bridges even if a window wasn't assigned because not all windows are required by downstream devices - Preserve bridge window type when releasing the resource, since the type is needed for reassignment - Consolidate selection of bridge windows into two new interfaces, pbus_select_window() and pbus_select_window_for_type(), so this is done consistently - Compute bridge window start and end earlier to avoid logging stale information MSI: - Add quirk to disable MSI on RDC PCI to PCIe bridges (Marcos Del Sol Vives) Error handling: - Align AER with EEH by allowing drivers to request a Bus Reset on Non-Fatal Errors (in addition to the reset on Fatal Errors that we already do) (Lukas Wunner) - If error recovery fails, emit FAILED_RECOVERY uevents for the devices, not for the bridge leading to them. This makes them correspond to BEGIN_RECOVERY uevents (Lukas Wunner) - Align AER with EEH by calling err_handler.error_detected() callbacks to notify drivers if error recovery fails (Lukas Wunner) - Align AER with EEH by restoring device error_state to pci_channel_io_normal before the err_handler.slot_reset() callback. This is earlier than before the err_handler.resume() callback (Lukas Wunner) - Emit a BEGIN_RECOVERY uevent when driver's err_handler.error_detected() requests a reset, as well as when it says recovery is complete or can be done without a reset (Niklas Schnelle) - Align s390 with AER and EEH by emitting uevents during error recovery (Niklas Schnelle) - Align EEH with AER and s390 by emitting BEGIN_RECOVERY, SUCCESSFUL_RECOVERY, or FAILED_RECOVERY uevents depending on the result of err_handler.error_detected() (Niklas Schnelle) - Fix a NULL pointer dereference in aer_ratelimit() when ACPI GHES error information identifies a device without an AER Capability (Breno Leitao) - Update error decoding and TLP Log printing for new errors in current PCIe base spec (Lukas Wunner) - Update error recovery documentation to match the current code and use consistent nomenclature (Lukas Wunner) ASPM: - Enable all ClockPM and ASPM states for devicetree platforms, since there's typically no firmware that enables ASPM This is a risky change that may uncover hardware or configuration defects at boot-time rather than when users enable ASPM via sysfs later. Booting with "pcie_aspm=off" prevents this enabling (Manivannan Sadhasivam) - Remove the qcom code that enabled ASPM (Manivannan Sadhasivam) Power management: - If a device has already been disconnected, e.g., by a hotplug removal, don't bother trying to resume it to D0 when detaching the driver. This avoids annoying "Unable to change power state from D3cold to D0" messages (Mario Limonciello) - Ensure devices are powered up before config reads for 'max_link_width', 'current_link_speed', 'current_link_width', 'secondary_bus_number', and 'subordinate_bus_number' sysfs files. This prevents using invalid data (~0) in drivers or lspci and, depending on how the PCIe controller reports errors, may avoid error interrupts or crashes (Brian Norris) Virtualization: - Add rescan/remove locking when enabling/disabling SR-IOV, which avoids list corruption on s390, where disabling SR-IOV also generates hotplug events (Niklas Schnelle) Peer-to-peer DMA: - Free struct p2p_pgmap, not a member within it, in the pci_p2pdma_add_resource() error path (Sungho Kim) Endpoint framework: - Document sysfs interface for BAR assignment of vNTB endpoint functions (Jerome Brunet) - Fix array underflow in endpoint BAR test case (Dan Carpenter) - Skip endpoint IRQ test if the IRQ is out of range to avoid false errors (Christian Bruel) - Fix endpoint test case for controllers with fixed-size BARs smaller than requested by the test (Marek Vasut) - Restore inbound translation when disabling doorbell so the endpoint doorbell test case can be run more than once (Niklas Cassel) - Avoid a NULL pointer dereference when releasing DMA channels in endpoint DMA test case (Shin'ichiro Kawasaki) - Convert tegra194 interrupt number to MSI vector to fix endpoint Kselftest MSI_TEST test case (Niklas Cassel) - Reset tegra194 BARs when running in endpoint mode so the BAR tests don't overwrite the ATU settings in BAR4 (Niklas Cassel) - Handle errors in tegra194 BPMP transactions so we don't mistakenly skip future PERST# assertion (Vidya Sagar) AMD MDB PCIe controller driver: - Update DT binding example to separate PERST# to a Root Port stanza to make multiple Root Ports possible in the future (Sai Krishna Musham) - Add driver support for PERST# being described in a Root Port stanza, falling back to the host bridge if not found there (Sai Krishna Musham) Freescale i.MX6 PCIe controller driver: - Enable the 3.3V Vaux supply if available so devices can request wakeup with either Beacon or WAKE# (Richard Zhu) MediaTek PCIe Gen3 controller driver: - Add optional sys clock ready time setting to avoid sys_clk_rdy signal glitching in MT6991 and MT8196 (AngeloGioacchino Del Regno) - Add DT binding and driver support for MT6991 and MT8196 (AngeloGioacchino Del Regno) NVIDIA Tegra PCIe controller driver: - When asserting PERST#, disable the controller instead of mistakenly disabling the PLL twice (Nagarjuna Kristam) - Convert struct tegra_msi mask_lock to raw spinlock to avoid a lock nesting error (Marek Vasut) Qualcomm PCIe controller driver: - Select PCI Power Control Slot driver so slot voltage rails can be turned on/off if described in Root Port devicetree node (Qiang Yu) - Parse only PCI bridge child nodes in devicetree, 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) - 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) - Add SM8750 compatible to qcom,pcie-sm8550.yaml (Krishna Chaitanya Chundru) - Update qcom,pcie-x1e80100.yaml to allow fifth PCIe host on Qualcomm Glymur, which is compatible with X1E80100 but doesn't have the cnoc_sf_axi clock (Qiang Yu) Renesas R-Car PCIe controller driver: - Fix a typo that prevented correct PHY initialization (Marek Vasut) - Add a missing 1ms delay after PWR reset assertion as required by the V4H manual (Marek Vasut) - Assure reset has completed before DBI access to avoid SError (Marek Vasut) - Fix inverted PHY initialization check, which sometimes led to timeouts and failure to start the controller (Marek Vasut) - Pass the correct IRQ domain to generic_handle_domain_irq() to fix a regression when converting to msi_create_parent_irq_domain() (Claudiu Beznea) - Drop the spinlock protecting the PMSR register - it's no longer required since pci_lock already serializes accesses (Marek Vasut) - Convert struct rcar_msi mask_lock to raw spinlock to avoid a lock nesting error (Marek Vasut) SOPHGO PCIe controller driver: - Check for existence of struct cdns_pcie.ops before using it to allow Cadence drivers that don't need to supply ops (Chen Wang) - Add DT binding and driver for the SOPHGO SG2042 PCIe controller (Chen Wang) STMicroelectronics STM32MP25 PCIe controller driver: - Update pinctrl documentation of initial states and use in runtime suspend/resume (Christian Bruel) - Add pinctrl_pm_select_init_state() for use by stm32 driver, which needs it during resume (Christian Bruel) - Add devicetree bindings and drivers for the STMicroelectronics STM32MP25 in host and endpoint modes (Christian Bruel) Synopsys DesignWare PCIe controller driver: - Add support for x16 in devicetree 'num-lanes' property (Konrad Dybcio) - Verify that if DT specifies a single IRQ for all eDMA channels, it is named 'dma' (Niklas Cassel) TI J721E PCIe driver: - Add MODULE_DEVICE_TABLE() so driver can be autoloaded (Siddharth Vadapalli) - Power controller off before configuring the glue layer so the controller latches the correct values on power-on (Siddharth Vadapalli) TI Keystone PCIe controller driver: - Use devm_request_irq() so 'ks-pcie-error-irq' is freed when driver exits with error (Siddharth Vadapalli) - Add Peripheral Virtualization Unit (PVU), which restricts DMA from PCIe devices to specific regions of host memory, to the ti,am65 binding (Jan Kiszka) Xilinx NWL PCIe controller driver: - Clear bootloader E_ECAM_CONTROL before merging in the new driver value to avoid writing invalid values (Jani Nurminen)" * tag 'pci-v6.18-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (141 commits) PCI/AER: Avoid NULL pointer dereference in aer_ratelimit() MAINTAINERS: Add entry for ST STM32MP25 PCIe drivers PCI: stm32-ep: Add PCIe Endpoint support for STM32MP25 dt-bindings: PCI: Add STM32MP25 PCIe Endpoint bindings PCI: stm32: Add PCIe host support for STM32MP25 PCI: xilinx-nwl: Fix ECAM programming PCI: j721e: Fix incorrect error message in probe() PCI: keystone: Use devm_request_irq() to free "ks-pcie-error-irq" on exit dt-bindings: PCI: qcom,pcie-x1e80100: Set clocks minItems for the fifth Glymur PCIe Controller PCI: dwc: Support 16-lane operation PCI: Add lockdep assertion in pci_stop_and_remove_bus_device() PCI/IOV: Add PCI rescan-remove locking when enabling/disabling SR-IOV PCI: rcar-host: Convert struct rcar_msi mask_lock into raw spinlock PCI: tegra194: Rename 'root_bus' to 'root_port_bus' in tegra_pcie_downstream_dev_to_D0() PCI: tegra: Convert struct tegra_msi mask_lock into raw spinlock PCI: rcar-gen4: Fix inverted break condition in PHY initialization PCI: rcar-gen4: Assure reset occurs before DBI access PCI: rcar-gen4: Add missing 1ms delay after PWR reset assertion PCI: Set up bridge resources earlier PCI: rcar-host: Drop PMSR spinlock ...

Merge branch 'pci/endpoint'

2025-10-03T17:13:15+00:00

- Check for errors returned from pci_epc_get(), which returns IS_ERR(), not NULL on error (Dan Carpenter) - Fix pci_endpoint_test_ioctl() array underflow (Dan Carpenter) - Document sysfs interface for BAR assignment of vNTB endpoint functions (Jerome Brunet) - Drop superfluous pci_epc_features initialization for unsupported features; we only have to mention features that *are* supported (Niklas Cassel) - Skip IRQ tests if the IRQ is out of range (Christian Bruel) - Fix pci-epf-test for controllers with fixed-size BARs smaller than requested by the test (Marek Vasut) - Restore inbound translation when disabling doorbell so the doorbell test case can be run more than once (Niklas Cassel) - Check for NULL before releasing DMA channels to avoid a NULL pointer dereference (Shin'ichiro Kawasaki) - Convert tegra194 interrupt number to MSI vector to fix endpoint Kselftest MSI_TEST test case (Niklas Cassel) - Set tegra_pcie_epc_features.msi_capable so the pci_endpoint_test can use the optimal IRQ type (Niklas Cassel) - Reset tegra194 BARs when running in endpoint mode so the BAR tests don't overwrite the ATU settings in BAR4 (Niklas Cassel) - Handle errors in tegra194 BPMP transactions so we don't mistakenly skip future PERST# assertion (Vidya Sagar) * pci/endpoint: PCI: tegra194: Handle errors in BPMP response PCI: tegra194: Reset BARs when running in PCIe endpoint mode PCI: tegra194: Set pci_epc_features::msi_capable to true PCI: tegra194: Fix broken tegra_pcie_ep_raise_msi_irq() PCI: endpoint: pci-epf-test: Add NULL check for DMA channels before release PCI: endpoint: pci-epf-test: Fix doorbell test support PCI: endpoint: pci-epf-test: Limit PCIe BAR size for fixed BARs selftests: pci_endpoint: Skip IRQ test if IRQ is out of range. misc: pci_endpoint_test: Cleanup extra 0 initialization misc: pci_endpoint_test: Skip IRQ tests if irq is out of range PCI: endpoint: Drop superfluous pci_epc_features initialization Documentation: PCI: endpoint: Document BAR assignment misc: pci_endpoint_test: Fix array underflow in pci_endpoint_test_ioctl() PCI: endpoint: pci-ep-msi: Fix NULL vs IS_ERR() check in pci_epf_write_msi_msg()

Documentation: PCI: Fix typos

2025-09-18T22:23:22+00:00

The PCIe spec uses "Requester ID", not "requestor ID". Follow the spec to avoid confusion. Signed-off-by: Emilio Perez [bhelgaas: capitalize as a hint that the spec defines this] Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250818023121.33427-1-emiliopeju@gmail.com

Documentation: PCI: Tidy error recovery doc's PCIe nomenclature

2025-09-16T15:53:40+00:00

Commit 11502feab423 ("Documentation: PCI: Tidy AER documentation") replaced the terms "PCI-E", "PCI-Express" and "PCI Express" with "PCIe" in the AER documentation. Do the same in the documentation on PCI error recovery. While at it, add a missing period and a missing blank. Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Brian Norris Reviewed-by: Niklas Schnelle Reviewed-by: Kuppuswamy Sathyanarayanan Link: https://patch.msgid.link/db56b7ef12043f709a04ce67c1d1e102ab5f4e19.1757942121.git.lukas@wunner.de

Documentation: PCI: Amend error recovery doc with DPC/AER specifics

2025-09-16T15:53:25+00:00

Amend the documentation on PCI error recovery with specifics about Downstream Port Containment and Advanced Error Reporting: * Explain that with DPC, devices are inaccessible upon an error (similar to EEH on powerpc) and do not become accessible until the link is re-enabled. * Explain that with AER, although devices may already be accessible in the ->error_detected() callback, accesses should be deferred to the ->mmio_enabled() callback for compatibility with EEH on powerpc and with s390. Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Brian Norris Reviewed-by: Niklas Schnelle Reviewed-by: Kuppuswamy Sathyanarayanan Link: https://patch.msgid.link/61d8eeadb20ee71c3a852f44c863bfe0209c454d.1757942121.git.lukas@wunner.de

Documentation: PCI: Sync error recovery doc with code

2025-09-16T15:53:03+00:00

Amend the documentation on PCI error recovery to fix minor inaccuracies vis-à-vis the actual code: * The documentation claims that a missing ->resume() or ->mmio_enabled() callback always leads to recovery through reset. But none of the implementations do this (pcie_do_recovery(), eeh_handle_normal_event(), zpci_event_do_error_state_clear()). Drop the claim to align the documentation with the code. * The documentation does not list PCI_ERS_RESULT_RECOVERED as a valid return value from ->error_detected(). But none of the implementations forbid this and some drivers are returning it, e.g.: drivers/bus/mhi/host/pci_generic.c drivers/infiniband/hw/hfi1/pcie.c Further down in the documentation it is implied that the return value is in fact allowed: "The platform will call the resume() callback on all affected device drivers if all drivers on the segment have returned PCI_ERS_RESULT_RECOVERED from one of the 3 previous callbacks." The "3 previous callbacks" being ->error_detected(), ->mmio_enabled() and ->slot_reset(). Add it to the valid return values for consistency. Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Brian Norris Reviewed-by: Niklas Schnelle Reviewed-by: Kuppuswamy Sathyanarayanan Link: https://patch.msgid.link/ed3c3385499775fcc25f1ee66f395e212919f94a.1757942121.git.lukas@wunner.de

Documentation: PCI: Sync AER doc with code

2025-09-16T15:52:07+00:00

The PCIe Advanced Error Reporting driver has evolved over the years but its documentation hasn't. Catch up with past code changes: * The documentation claims that Correctable Errors are logged with KERN_INFO severity, but the code uses KERN_WARN. It had used KERN_WARN from the beginning with commit 6c2b374d7485 ("PCI-Express AER implemetation: AER core and aerdriver"). In 2013, commit 2cced2d95961 ("aerdrv: Cleanup log output for AER") switched to KERN_ERR, until 2020 when it was reverted back to KERN_WARN by commit e83e2ca3c395 ("PCI/AER: Log correctable errors as warning, not error"). * An example log message in the documentation uses the term "Uncorrected", but the code uses "Uncorrectable" since commit 02a06f5f1a6a ("PCI/AER: Use 'Correctable' and 'Uncorrectable' spec terms for errors"). * The example contains the Requester ID "id=0500", which is omitted since commit 010caed4ccb6 ("PCI/AER: Decode Error Source Requester ID"). * The example contains the error name "Unsupported Request", which is instead reported as "UnsupReq" since commit bd237801fef2 ("PCI/AER: Adopt lspci names for AER error decoding"). * The example doesn't prepend "0x" to hex values from the TLP Header Log, as introduced by commit f68ea779d98a ("PCI: Add pcie_print_tlp_log() to print TLP Header and Prefix Log"). * The documentation refers to a reset_link callback which was removed by commit b6cf1a42f916 ("PCI/ERR: Remove service dependency in pcie_do_recovery()"). * Commit 579086225502 ("PCI/ERR: Recover from RCiEP AER errors") added support to recover Root Complex Integrated Endpoints by applying a Function Level Reset, alternatively to the Secondary Bus Reset which is applied otherwise. * On non-fatal errors, a reset was previously never performed. But the AER driver has just been amended to allow drivers to opt in to a reset. * The documentation claims that a warning message is logged if a driver lacks pci_error_handlers. But the message has been informational (logged with KERN_INFO severity) since its introduction with commit 01daacfb9035 ("PCI/AER: Log which device prevents error recovery"). The documentation claims that the message is only logged for fatal errors, which is incorrect. Moreover it refers to "section 3", even though the documentation no longer contains section numbers since commit 4e37f055a92e ("Documentation: PCI: convert pcieaer-howto.txt to reST"). Section 3 is titled "Developer Guide". That's the same section where the reference is located, so it is self-referential and can be dropped. Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Brian Norris Reviewed-by: Kuppuswamy Sathyanarayanan Link: https://patch.msgid.link/7501bfc5b9920193a25998a3cbcf72c47674ec63.1757942121.git.lukas@wunner.de

Documentation: Fix PCI typos

2025-08-18T16:31:19+00:00

Fix typos. Signed-off-by: Bjorn Helgaas Reviewed-by: Randy Dunlap Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20250813200526.290420-2-helgaas@kernel.org

Documentation: PCI: endpoint: Document BAR assignment

2025-08-13T21:25:10+00:00

It is now possible to assign BARs while creating a vNTB endpoint function. Update the documentation accordingly. Suggested-by: Bjorn Helgaas Signed-off-by: Jerome Brunet Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250731-vntb-doc-v1-1-95a0e0cd28d0@baylibre.com