The documentation of the Rock Pi X is a mess. The naming conventions are not consistent, so actual device can’t be determined for the signal names of the GPIO connector.
The EDS and data sheet documentation naming are also different, even in the same document chapters and also between documents.
As the documents mixes zero based numbering of devices with one based numbering, it’s hard to determine the device signal actually connected to the 40-pin connector.
There is one UART intended for debugging and two high speed UARTs. In the GPIO connector chart you have ISH_UART_TX, UART0_TX, UART0_RX, UART2_TX and UART2_RX for example. You seem to have your own naming in the chart.
It would be convenient if you could document the PCI device number and function number for each signal in the GPIO connector chart. A simple list with all the signals would clarify which device they belong to.
As I have noticed with the FITC tool, all the SIO devices are enabled even though they are not used on the board. Also the SATA device is enabled, even though it doesn’t exist on the T3 version of Z8350.