| Trusted Firmware-A for Allwinner ARMv8 SoCs |
| =========================================== |
| |
| Trusted Firmware-A (TF-A) implements the EL3 firmware layer for Allwinner |
| SoCs with ARMv8 cores. Only BL31 is used to provide proper EL3 setup and |
| PSCI runtime services. |
| U-Boot's SPL acts as a loader, loading both BL31 and BL33 (typically U-Boot). |
| Loading is done from SD card, eMMC or SPI flash, also via an USB debug |
| interface (FEL). |
| BL31 lives in SRAM A2, which is documented to be accessible from secure |
| world only. |
| |
| Current limitations: |
| |
| - Missing PMIC support |
| |
| After building bl31.bin, the binary must be fed to the U-Boot build system |
| to include it in the FIT image that the SPL loader will process. |
| bl31.bin can be either copied (or sym-linked) into U-Boot's root directory, |
| or the environment variable BL31 must contain the binary's path. |
| See the respective `U-Boot documentation`_ for more details. |
| |
| To build: |
| |
| :: |
| |
| make CROSS_COMPILE=aarch64-linux-gnu- PLAT=sun50i_a64 DEBUG=1 bl31 |
| |
| .. _U-Boot documentation: http://git.denx.de/?p=u-boot.git;f=board/sunxi/README.sunxi64;hb=HEAD |