pcie-mhi
pci_mhi.ko
r8a774b1-hihope-rzg2n-ex.dts
lspci
By default, the PCIe driver should be enabled in the default Renesas BSP.
https://github.com/renesas-rz/rz_linux-cip/blob/rzv2h-5.10-cip17/arch/arm64/configs/defconfig#L105
CONFIG_PCIE_RCAR_HOST=yCONFIG_PCIE_RCAR_EP=y
So if you enabled it in your Device Tree, it should be OK.