| Message ID | 1687368849-36722-1-git-send-email-lizhi.hou@amd.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Generate device tree node for pci devices | expand |
On Wed, Jun 21, 2023 at 10:34:04AM -0700, Lizhi Hou wrote: > This patch series introduces OF overlay support for PCI devices which > primarily addresses two use cases. First, it provides a data driven method > to describe hardware peripherals that are present in a PCI endpoint and > hence can be accessed by the PCI host. Second, it allows reuse of a OF > compatible driver -- often used in SoC platforms -- in a PCI host based > system. > > There are 2 series devices rely on this patch: > > 1) Xilinx Alveo Accelerator cards (FPGA based device) > 2) Microchip LAN9662 Ethernet Controller > > Please see: https://lore.kernel.org/lkml/20220427094502.456111-1-clement.leger@bootlin.com/ > > Normally, the PCI core discovers PCI devices and their BARs using the > PCI enumeration process. However, the process does not provide a way to > discover the hardware peripherals that are present in a PCI device, and > which can be accessed through the PCI BARs. Also, the enumeration process > does not provide a way to associate MSI-X vectors of a PCI device with the > hardware peripherals that are present in the device. PCI device drivers > often use header files to describe the hardware peripherals and their > resources as there is no standard data driven way to do so. This patch > series proposes to use flattened device tree blob to describe the > peripherals in a data driven way. Based on previous discussion, using > device tree overlay is the best way to unflatten the blob and populate > platform devices. To use device tree overlay, there are three obvious > problems that need to be resolved. > > First, we need to create a base tree for non-DT system such as x86_64. A > patch series has been submitted for this: > https://lore.kernel.org/lkml/20220624034327.2542112-1-frowand.list@gmail.com/ > https://lore.kernel.org/lkml/20220216050056.311496-1-lizhi.hou@xilinx.com/ > > Second, a device tree node corresponding to the PCI endpoint is required > for overlaying the flattened device tree blob for that PCI endpoint. > Because PCI is a self-discoverable bus, a device tree node is usually not > created for PCI devices. This series adds support to generate a device > tree node for a PCI device which advertises itself using PCI quirks > infrastructure. > > Third, we need to generate device tree nodes for PCI bridges since a child > PCI endpoint may choose to have a device tree node created. > > This patch series is made up of three patches. > > The first patch is adding OF interface to create or destroy OF node > dynamically. > > The second patch introduces a kernel option, CONFIG_DYNAMIC_PCI_OF_NODEX. In case this log becomes part of the merge commit or something, s/CONFIG_DYNAMIC_PCI_OF_NODEX/CONFIG_PCI_DYNAMIC_OF_NODES/ > When the option is turned on, the kernel will generate device tree nodes > for all PCI bridges unconditionally. The patch also shows how to use the > PCI quirks infrastructure, DECLARE_PCI_FIXUP_FINAL to generate a device > tree node for a device. Specifically, the patch generates a device tree > node for Xilinx Alveo U50 PCIe accelerator device. The generated device > tree nodes do not have any property. > > The third patch adds basic properties ('reg', 'compatible' and > 'device_type') to the dynamically generated device tree nodes. More > properties can be added in the future. > > Here is the example of device tree nodes generated within the ARM64 QEMU. It's not obvious to me what was there originally and what was added because of this series. > # lspci -t > -[0000:00]-+-00.0 > +-01.0 > +-03.0-[01-03]----00.0-[02-03]----00.0-[03]----00.0 > +-03.1-[04]-- > \-04.0-[05-06]----00.0-[06]-- > # tree /sys/firmware/devicetree/base/pcie\@10000000 > /sys/firmware/devicetree/base/pcie@10000000 > |-- #address-cells > |-- #interrupt-cells > |-- #size-cells > |-- bus-range > |-- compatible > |-- device_type > |-- dma-coherent > |-- interrupt-map > |-- interrupt-map-mask > |-- linux,pci-domain > |-- msi-map > |-- name > |-- pci@3,0 > | |-- #address-cells > | |-- #size-cells > | |-- compatible > | |-- device_type > | |-- pci@0,0 > | | |-- #address-cells > | | |-- #size-cells > | | |-- compatible > | | |-- device_type > | | |-- pci@0,0 > | | | |-- #address-cells > | | | |-- #size-cells > | | | |-- compatible > | | | |-- dev@0,0 > | | | | |-- #address-cells > | | | | |-- #size-cells > | | | | |-- compatible > | | | | |-- ranges > | | | | `-- reg > | | | |-- device_type > | | | |-- ranges > | | | `-- reg > | | |-- ranges > | | `-- reg > | |-- ranges > | `-- reg > |-- pci@3,1 > | |-- #address-cells > | |-- #size-cells > | |-- compatible > | |-- device_type > | |-- ranges > | `-- reg > |-- pci@4,0 > | |-- #address-cells > | |-- #size-cells > | |-- compatible > | |-- device_type > | |-- pci@0,0 > | | |-- #address-cells > | | |-- #size-cells > | | |-- compatible > | | |-- device_type > | | |-- ranges > | | `-- reg > | |-- ranges > | `-- reg > |-- ranges > `-- reg
This patch series introduces OF overlay support for PCI devices which primarily addresses two use cases. First, it provides a data driven method to describe hardware peripherals that are present in a PCI endpoint and hence can be accessed by the PCI host. Second, it allows reuse of a OF compatible driver -- often used in SoC platforms -- in a PCI host based system. There are 2 series devices rely on this patch: 1) Xilinx Alveo Accelerator cards (FPGA based device) 2) Microchip LAN9662 Ethernet Controller Please see: https://lore.kernel.org/lkml/20220427094502.456111-1-clement.leger@bootlin.com/ Normally, the PCI core discovers PCI devices and their BARs using the PCI enumeration process. However, the process does not provide a way to discover the hardware peripherals that are present in a PCI device, and which can be accessed through the PCI BARs. Also, the enumeration process does not provide a way to associate MSI-X vectors of a PCI device with the hardware peripherals that are present in the device. PCI device drivers often use header files to describe the hardware peripherals and their resources as there is no standard data driven way to do so. This patch series proposes to use flattened device tree blob to describe the peripherals in a data driven way. Based on previous discussion, using device tree overlay is the best way to unflatten the blob and populate platform devices. To use device tree overlay, there are three obvious problems that need to be resolved. First, we need to create a base tree for non-DT system such as x86_64. A patch series has been submitted for this: https://lore.kernel.org/lkml/20220624034327.2542112-1-frowand.list@gmail.com/ https://lore.kernel.org/lkml/20220216050056.311496-1-lizhi.hou@xilinx.com/ Second, a device tree node corresponding to the PCI endpoint is required for overlaying the flattened device tree blob for that PCI endpoint. Because PCI is a self-discoverable bus, a device tree node is usually not created for PCI devices. This series adds support to generate a device tree node for a PCI device which advertises itself using PCI quirks infrastructure. Third, we need to generate device tree nodes for PCI bridges since a child PCI endpoint may choose to have a device tree node created. This patch series is made up of three patches. The first patch is adding OF interface to create or destroy OF node dynamically. The second patch introduces a kernel option, CONFIG_DYNAMIC_PCI_OF_NODEX. When the option is turned on, the kernel will generate device tree nodes for all PCI bridges unconditionally. The patch also shows how to use the PCI quirks infrastructure, DECLARE_PCI_FIXUP_FINAL to generate a device tree node for a device. Specifically, the patch generates a device tree node for Xilinx Alveo U50 PCIe accelerator device. The generated device tree nodes do not have any property. The third patch adds basic properties ('reg', 'compatible' and 'device_type') to the dynamically generated device tree nodes. More properties can be added in the future. Here is the example of device tree nodes generated within the ARM64 QEMU. # lspci -t -[0000:00]-+-00.0 +-01.0 +-03.0-[01-03]----00.0-[02-03]----00.0-[03]----00.0 +-03.1-[04]-- \-04.0-[05-06]----00.0-[06]-- # tree /sys/firmware/devicetree/base/pcie\@10000000 /sys/firmware/devicetree/base/pcie@10000000 |-- #address-cells |-- #interrupt-cells |-- #size-cells |-- bus-range |-- compatible |-- device_type |-- dma-coherent |-- interrupt-map |-- interrupt-map-mask |-- linux,pci-domain |-- msi-map |-- name |-- pci@3,0 | |-- #address-cells | |-- #size-cells | |-- compatible | |-- device_type | |-- pci@0,0 | | |-- #address-cells | | |-- #size-cells | | |-- compatible | | |-- device_type | | |-- pci@0,0 | | | |-- #address-cells | | | |-- #size-cells | | | |-- compatible | | | |-- dev@0,0 | | | | |-- #address-cells | | | | |-- #size-cells | | | | |-- compatible | | | | |-- ranges | | | | `-- reg | | | |-- device_type | | | |-- ranges | | | `-- reg | | |-- ranges | | `-- reg | |-- ranges | `-- reg |-- pci@3,1 | |-- #address-cells | |-- #size-cells | |-- compatible | |-- device_type | |-- ranges | `-- reg |-- pci@4,0 | |-- #address-cells | |-- #size-cells | |-- compatible | |-- device_type | |-- pci@0,0 | | |-- #address-cells | | |-- #size-cells | | |-- compatible | | |-- device_type | | |-- ranges | | `-- reg | |-- ranges | `-- reg |-- ranges `-- reg Changes since v9: - Minor code review fixes Changes since v8: - Added patches to create unit test to verifying address translation The test relies on QEMU PCI Test Device, please see https://github.com/houlz0507/xoclv2/blob/pci-dt-0329/pci-dt-patch-0329/README for test setup - Minor code review fixes Changes since v7: - Modified dynamic node creation interfaces - Added unittest for new added interfaces Changes since v6: - Removed single line wrapper functions - Added Signed-off-by Clément Léger <clement.leger@bootlin.com> Changes since v5: - Fixed code review comments - Fixed incorrect 'ranges' and 'reg' properties Changes since RFC v4: - Fixed code review comments Changes since RFC v3: - Split the Xilinx Alveo U50 PCI quirk to a separate patch - Minor changes in commit description and code comment Changes since RFC v2: - Merged patch 3 with patch 2 - Added OF interfaces of_changeset_add_prop_* and use them to create properties. - Added '#address-cells', '#size-cells' and 'ranges' properties. Changes since RFC v1: - Added one patch to create basic properties. - To move DT related code out of PCI subsystem, replaced of_node_alloc() with of_create_node()/of_destroy_node() Lizhi Hou (5): of: dynamic: Add interfaces for creating device node dynamically PCI: Create device tree node for selected devices PCI: Add PCI quirks to generate device tree node for Xilinx Alveo U50 of: overlay: Extend of_overlay_fdt_apply() to specify the target node of: unittest: Add pci_dt_testdrv pci driver drivers/of/dynamic.c | 164 ++++++++++++++ drivers/of/overlay.c | 42 +++- drivers/of/unittest-data/Makefile | 3 +- .../of/unittest-data/overlay_pci_node.dtso | 22 ++ drivers/of/unittest.c | 210 +++++++++++++++++- drivers/pci/Kconfig | 12 + drivers/pci/Makefile | 1 + drivers/pci/bus.c | 2 + drivers/pci/of.c | 81 ++++++- drivers/pci/of_property.c | 194 ++++++++++++++++ drivers/pci/pci.h | 19 ++ drivers/pci/quirks.c | 12 + drivers/pci/remove.c | 1 + include/linux/of.h | 25 ++- 14 files changed, 772 insertions(+), 16 deletions(-) create mode 100644 drivers/of/unittest-data/overlay_pci_node.dtso create mode 100644 drivers/pci/of_property.c