Hello, This V1 of patch series is to provide the required pci OF interfaces for the PCIe device which uses flattened device tree to describe apertures in its PCIe BARs. e.g, Xilinx Alveo PCIe accelerator. This requires a base device tree which contains nodes for PCIe devices. A PCIe device driver can then overlay a flattened device tree on the PCIe device tree node. There are two separate parts for this to work. First, not all system has a base device tree created by default. Thus, a patch to create an empty device tree root node has been submitted. https://lore.kernel.org/lkml/20220216050056.311496-1-lizhi.hou@xxxxxxxxxx/ Second, PCIe is self discoverable bus and there might not be a device tree node created for PCIe device. This patch provides a new interface to create a ‘pci-ep-bus’ node under the base device tree root node. PCIe device driver may call this interface in its probe routine to create device tree node, then overlays its device tree to the node. For the overlayed device tree nodes, each node presents a hardware aperture implemented in its PCIe BARs. The aperture register address consists of BAR index and offset. It uses the following encoding: 0xIooooooo 0xoooooooo Where: I = BAR index ooooooo oooooooo = BAR offset The ‘pci-ep-bus’ node been created is compatible with ‘simple-bus’ and contains ‘ranges’ property for translating aperture address to CPU address. The last patch enhances of_overlay_fdt_apply(). The ‘pci-ep-bus’ device node is created dynamically. The flattened device tree may not specify an fixed target overlay path in front. Instead, a relative path to the ‘pci-ep-bus’ node is specified in the flattened tree. Thus, a new parameter is added to point the target base node which is ‘pci-ep-bus’ node in this case. Then the entire overlay target path is target base node path plus the relative path specified in the flattened device tree. Lizhi Hou (4): pci: add interface to create pci-ep device tree node Documentation: devicetree: bindings: add binding for PCIe endpoint bus fpga: xrt: management physical function driver of: enhance overlay applying interface to specific target base node .../devicetree/bindings/bus/pci-ep-bus.yaml | 72 +++++++ drivers/fpga/Kconfig | 3 + drivers/fpga/Makefile | 3 + drivers/fpga/xrt/Kconfig | 24 +++ drivers/fpga/xrt/Makefile | 8 + drivers/fpga/xrt/mgmt/Makefile | 13 ++ drivers/fpga/xrt/mgmt/dt-test.dts | 15 ++ drivers/fpga/xrt/mgmt/dt-test.h | 15 ++ drivers/fpga/xrt/mgmt/xmgmt-drv.c | 102 ++++++++++ drivers/gpu/drm/rcar-du/rcar_du_of.c | 2 +- drivers/of/overlay.c | 37 ++-- drivers/of/unittest.c | 2 +- drivers/pci/of.c | 180 ++++++++++++++++++ include/linux/of.h | 2 +- include/linux/of_pci.h | 15 ++ 15 files changed, 479 insertions(+), 14 deletions(-) create mode 100644 Documentation/devicetree/bindings/bus/pci-ep-bus.yaml create mode 100644 drivers/fpga/xrt/Kconfig create mode 100644 drivers/fpga/xrt/Makefile create mode 100644 drivers/fpga/xrt/mgmt/Makefile create mode 100644 drivers/fpga/xrt/mgmt/dt-test.dts create mode 100644 drivers/fpga/xrt/mgmt/dt-test.h create mode 100644 drivers/fpga/xrt/mgmt/xmgmt-drv.c -- 2.27.0
