Messages in this thread | | | Date | Tue, 8 Nov 2022 10:29:37 -0800 | Subject | Re: [PATCH RFC V3 2/2] PCI: Create device tree node for selected devices | From | Lizhi Hou <> |
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Hi Bjorn,
Thanks for your comments. I will fix all these with next submission.
Lizhi
On 11/7/22 13:05, Bjorn Helgaas wrote: > On Fri, Nov 04, 2022 at 08:24:14AM -0700, Lizhi Hou wrote: >> The PCIe endpoint device such as Xilinx Alveo PCIe card maps the register >> spaces from multiple hardware peripherals to its PCIe BAR. Normally, >> the PCI core discovers devices and BARs using the PCI enumeration process. >> There is no infrastructure to discover the hardware peripherals that are >> present in a PCI device, and which can be accessed through the PCI BARs. >> >> For Alveo PCIe card, the card firmware provides a flattened device tree to >> describe the hardware peripherals on its BARs. The Alveo card driver can >> load this flattened device tree and leverage device tree framework to >> generate platform devices for the hardware peripherals eventually. >> >> Apparently, the device tree framework requires a device tree node for the >> PCIe device. Thus, it can generate the device tree nodes for hardware >> peripherals underneath. Because PCIe is self discoverable bus, there might >> not be a device tree node created for PCIe devices. This patch is to add >> support to generate device tree node for PCIe devices. It introduces a >> kernel option. When the option is turned on, the kernel will generate > Specify the kernel option here. These last two sentences should > probably be a separate paragraph because they say specifically what > this patch does. > >> device tree nodes for PCI bridges unconditionally. >> It will also generate >> a device tree node for Xilinx Alveo U50 by using PCI quirks. > I think I would split the Xilinx Alveo U50 quirk to a separate patch > from the infrastructure and make this patch more generic. > >> +config PCI_DYNAMIC_OF_NODES >> + bool "Device tree node for PCI devices" >> + depends on OF >> + select OF_DYNAMIC >> + help >> + This option enables support for generating device tree nodes for some >> + PCI devices. Thus, the driver of this kind can load and overlay >> + flattened device tree for its downstream devices. >> + >> + Once this option is selected, the device tree nodes will be generated >> + for all PCI/PCIE bridges. > PCI/PCIe > > Actually, in this context (and in the commit log), you should just say > "PCI" because there's nothing PCIe-specific here. > >> +void of_pci_make_dev_node(struct pci_dev *pdev) >> +{ >> + struct device_node *parent, *dt_node = NULL; >> + const char *pci_type = "dev"; >> + struct of_changeset *cset; >> + const char *full_name; >> + int ret; >> + >> + /* >> + * if there is already a device tree node linked to this device, >> + * return immediately. > s/if there/If there/ > >> + */ >> + if (pci_device_to_OF_node(pdev)) >> + return; >> + >> + /* check if there is device tree node for parent device */ > s/check/Check/ > > Follow the style of the file, which is "capitalize English sentences."
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