diff --git a/docs/plat/allwinner.rst b/docs/plat/allwinner.rst index b6969896a..1bf4f516b 100644 --- a/docs/plat/allwinner.rst +++ b/docs/plat/allwinner.rst @@ -26,6 +26,22 @@ To build for machines with an H616 or H313 SoC: make CROSS_COMPILE=aarch64-linux-gnu- PLAT=sun50i_h616 DEBUG=1 bl31 +Platform-specific build options +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The default build options should generate a working firmware image. There are +some build options that allow to fine-tune the firmware, or to disable support +for optional features. + +- ``SUNXI_SETUP_REGULATORS`` : On SoCs that typically ship with a PMIC + power management controller, BL31 tries to set up all needed power rails, + programming them to their respective voltages. That allows bootloader + software like U-Boot to ignore power control via the PMIC. + This setting defaults to 1. In some situations that enables too many + regulators, or some regulators need to be enabled in a very specific + sequence. To avoid problems with those boards, ``SUNXI_SETUP_REGULATORS`` + can bet set to ``0`` on the build command line, to skip the PMIC setup + entirely. Any bootloader or OS would need to setup the PMIC on its own then. Installation ------------