[coreboot] GPIOs on CS5536 based boards

[Daniel Mack]

Hi,

I'm developing on a CS5536 based board (ALIX.2D) and I'm trying to get
access to the GPIO registers in order to set the LEDs on bootup.

However, I seem to miss an mandatory point when trying so. As a quick
hack, I added these lines to the end of southbridge_init() in
coreboot-v3/southbridge/amd/cs5536/cs5536.c:

  outl(GPIOL_6_SET, GPIO_IO_BASE + GPIOL_OUTPUT_ENABLE);
  outl(GPIOL_6_CLEAR, GPIO_IO_BASE + GPIOL_OUTPUT_VALUE);

According to the schematics, GPIO6 is connected to one of the LEDs found
on the board, but the GPIO level does not change. I tried reading back
another GPIO but the READ_BACK register reads 0xffffffff, even though
the uppermost 16 bits are supposed to be 0 always. So I assume I missed
some basic point.

The MSR mapping should be set up at this point, as there are accesses to
other GPIO related registers called from the same function.

Any pointers, anyone?

Thanks,
Daniel