Re: [PATCH V7 0/3] Generate device tree node for pci devices

From: Frank Rowand
Date: Thu Mar 09 2023 - 00:56:29 EST

On 3/8/23 23:52, Frank Rowand wrote:
> On 1/19/23 21:02, 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
>

Sorry, hit send too quickly...

> Can someone please provide me a link to both:
>
> - a high level specification sheet
> - a detailed data sheet/programming manual

for the lan9662 PCIe card

-Frank

>
> -Frank
>
>
>>
>> Please see: https://lore.kernel.org/lkml/20220427094502.456111-1-clement.leger@xxxxxxxxxxx/
>>
>> 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@xxxxxxxxx/
>> https://lore.kernel.org/lkml/20220216050056.311496-1-lizhi.hou@xxxxxxxxxx/
>>
>> 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-[01]--
>> +-01.1-[02]----00.0
>> +-01.2-[03]----00.0
>> +-01.3-[04]----00.0
>> +-01.4-[05]----00.0
>> +-01.5-[06]--
>> +-01.6-[07]--
>> +-01.7-[08]--
>> +-02.0-[09-0b]----00.0-[0a-0b]----00.0-[0b]--+-00.0
>> | \-00.1
>> +-02.1-[0c]--
>> \-03.0-[0d-0e]----00.0-[0e]----01.0
>>
>> # 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-parent
>> |-- name
>> |-- pci@1,0
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@1,1
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@1,2
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@1,3
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@1,4
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@1,5
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@1,6
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@1,7
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@2,0
>> | |-- #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
>> | | | | |-- compatible
>> | | | | `-- reg
>> | | | |-- dev@0,1
>> | | | | |-- compatible
>> | | | | `-- reg
>> | | | |-- device_type
>> | | | |-- ranges
>> | | | `-- reg
>> | | |-- ranges
>> | | `-- reg
>> | |-- ranges
>> | `-- reg
>> |-- pci@2,1
>> | |-- #address-cells
>> | |-- #size-cells
>> | |-- compatible
>> | |-- device_type
>> | |-- ranges
>> | `-- reg
>> |-- pci@3,0
>> | |-- #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 v6:
>> - Removed single line wrapper functions
>> - Added Signed-off-by Clément Léger <clement.leger@xxxxxxxxxxx>
>>
>> Changes since v5:
>> - Fixed code review comments
>> - Fixed incorrect 'ranges' and 'reg' properties and verified address
>> translation.
>>
>> 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 (3):
>> 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
>>
>> drivers/of/dynamic.c | 197 +++++++++++++++++++++++++++++++++
>> drivers/pci/Kconfig | 12 ++
>> drivers/pci/Makefile | 1 +
>> drivers/pci/bus.c | 2 +
>> drivers/pci/msi/irqdomain.c | 6 +-
>> drivers/pci/of.c | 71 ++++++++++++
>> drivers/pci/of_property.c | 212 ++++++++++++++++++++++++++++++++++++
>> drivers/pci/pci-driver.c | 3 +-
>> drivers/pci/pci.h | 19 ++++
>> drivers/pci/quirks.c | 11 ++
>> drivers/pci/remove.c | 1 +
>> include/linux/of.h | 24 ++++
>> 12 files changed, 556 insertions(+), 3 deletions(-)
>> create mode 100644 drivers/pci/of_property.c
>>
>