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."
