Change in coreboot[master]: drivers/pcie/rtd3/device: Add PCIe RTD3 driver

[Furquan Shaikh (Code Review)]

Attention is currently required from: Jason Glenesk, Raul Rangel, Marshall Dawson, Tim Wawrzynczak, Karthik Ramasubramanian, Felix Held.
Furquan Shaikh has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/54966 )

Change subject: drivers/pcie/rtd3/device: Add PCIe RTD3 driver
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Patch Set 4:

(1 comment)

File src/soc/amd/common/block/rtd3/rtd3.c:

https://review.coreboot.org/c/coreboot/+/54966/comment/4082459f_75ca444f 
PS1, Line 210: pci_dev_read_resources
> So with this approach, the rtd3 driver doesn't write the actual Device node, but just writes a Power […]

We don't really define downstream PCI devices in DSDT or SSDT (https://www.kernel.org/doc/html/latest/PCI/acpi-info.html). Since those are discoverable by the OS, we don't really expose them in ACPI. In this case, I think the rtd3 driver will have to generate the device node i.e. call acpi_device_write_pci_dev and then add the power resource since that falls under "However, ACPI may describe PCI devices if it provides power management or hotplug functionality for them or if the device has INTx interrupts connected by platform interrupt controllers and a _PRT is needed to describe those connections."