My custom hardware is based on iMX6Q processor and design most similar to nitrogen6_max and I'm using nitogen6_max uboot and dtbs.
Attached document says the parameters of PCIe_PHY can be adjusted by changing the IOMUXC_GPR8 register settings to get the test passed.
1) Where can I find above 0x20e0020 register in uboot ? Do I need to add that line to uboot ?
2) What values should I change to tweak PCIE signal ? When I go through nitrogen6_max uboot I can see following lines in two files. So what values should I change to tweak PCIE signal ?
File path >> arch/arm/include/asm/arch-mx6/iomux.h
File path >> drivers/pci/pcie_imx.c
3) Can you give me an example how to tweak PCIE signals using GPR8 register ?