Hi, This series adds support to enumerate the PCIe endpoint devices using the Qcom specific 'Link up' event in 'global' IRQ. Historically, Qcom PCIe RC controllers lacked standard hotplug support. So when an endpoint is attached to the SoC, users have to rescan the bus manually to enumerate the device. But this can be avoided by rescanning the bus upon receiving 'Link up' event. Qcom PCIe RC controllers are capable of generating the 'global' SPI interrupt to the host CPUs. The device driver can use this interrupt to identify events such as PCIe link specific events, safety events etc... One such event is the PCIe Link up event generated when an endpoint is detected on the bus and the Link is 'up'. This event can be used to enumerate the endpoint devices. So add support for capturing the PCIe Link up event using the 'global' interrupt in the driver. Once the Link up event is received, the bus underneath the host bridge is scanned to enumerate PCIe endpoint devices. This series also has some cleanups to the Qcom PCIe EP controller driver for interrupt handling. NOTE: During v2 review, there was a discussion about removing the devices when 'Link Down' event is received. But this needs some more investigation, so I'm planning to add it later. Testing ======= This series is tested on Qcom SM8450 based development board that has 2 SoCs connected over PCIe. Merging Strategy ================ I'm expecting the binding and PCI driver changes to go through PCI tree and DTS patches through Qcom tree. - Mani Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> --- Changes in v4: - Fixed the indendation issue reported by Kbot - Merged the bindings patch adding global IRQ into one as suggested by Rob - Collected review tag - Link to v3: https://lore.kernel.org/r/20240731-pci-qcom-hotplug-v3-0-a1426afdee3b@xxxxxxxxxx Changes in v3: - Removed the usage of 'simulating hotplug' and just used 'Link up' as we are not fully emulating the hotplug support - Fixed the build issue wtih CONFIG_PCI_DOMAINS_GENERIC - Moved the 'global' IRQ entry to last in the binding and also mentioned the ABI break and its necessity in patch description. - Collected tags - Rebased on top of v6.11-rc1 - Link to v2: https://lore.kernel.org/r/20240717-pci-qcom-hotplug-v2-0-71d304b817f8@xxxxxxxxxx Changes in v2: - Added CONFIG_PCI_DOMAINS_GENERIC guard for domain_nr - Switched to dev_WARN_ONCE() for unhandled interrupts - Squashed the 'linux,pci-domain' bindings patches into one - Link to v1: https://lore.kernel.org/r/20240715-pci-qcom-hotplug-v1-0-5f3765cc873a@xxxxxxxxxx --- Manivannan Sadhasivam (12): PCI: qcom-ep: Drop the redundant masking of global IRQ events PCI: qcom-ep: Reword the error message for receiving unknown global IRQ event dt-bindings: PCI: pci-ep: Update Maintainers dt-bindings: PCI: pci-ep: Document 'linux,pci-domain' property PCI: endpoint: Assign PCI domain number for endpoint controllers PCI: qcom-ep: Modify 'global_irq' and 'perst_irq' IRQ device names ARM: dts: qcom: sdx55: Add 'linux,pci-domain' to PCIe EP controller node ARM: dts: qcom: sdx65: Add 'linux,pci-domain' to PCIe EP controller node arm64: dts: qcom: sa8775p: Add 'linux,pci-domain' to PCIe EP controller nodes dt-bindings: PCI: qcom,pcie-sm8450: Add 'global' interrupt PCI: qcom: Enumerate endpoints based on Link up event in 'global_irq' interrupt arm64: dts: qcom: sm8450: Add 'global' interrupt to the PCIe RC node Documentation/devicetree/bindings/pci/pci-ep.yaml | 14 +++++- .../devicetree/bindings/pci/qcom,pcie-common.yaml | 4 +- .../devicetree/bindings/pci/qcom,pcie-ep.yaml | 1 + .../devicetree/bindings/pci/qcom,pcie-sm8450.yaml | 10 ++-- arch/arm/boot/dts/qcom/qcom-sdx55.dtsi | 1 + arch/arm/boot/dts/qcom/qcom-sdx65.dtsi | 1 + arch/arm64/boot/dts/qcom/sa8775p.dtsi | 2 + arch/arm64/boot/dts/qcom/sm8450.dtsi | 12 +++-- drivers/pci/controller/dwc/pcie-qcom-ep.c | 21 +++++++-- drivers/pci/controller/dwc/pcie-qcom.c | 55 +++++++++++++++++++++- drivers/pci/endpoint/pci-epc-core.c | 14 ++++++ include/linux/pci-epc.h | 2 + 12 files changed, 120 insertions(+), 17 deletions(-) --- base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b change-id: 20240715-pci-qcom-hotplug-bcde1c13d91f Best regards, -- Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
