I have searched the manuals for i.mx6 quad but I cannot find any info on power-up config for GPIOs. As we need to connect some specific hardware to i.mx6, we need to know how pads are configured before any additional configuration done by u-boot or kernel itself. I have already modified the kernel and u-boot scripts for these signals, but I have no idea how are they configured during power-up. We are also using some signals which are defaulted to some other function (UART for instance), but can be configured as GPIOs. However I cannot find any info how they behave before they are actually configured as either GPIOs (alternate function) or default function.
The most logical way would be to configure all the GPIOs as inputs (with pullups or similar), but I cannot find this info anywhere. I have no clear picture how any of the pads are configured before u-boot or kernel kicks in. If anyone can point me in the right direction here I would be very grateful.