uboot_raspi3.md

How to use u-boot to boot rCore in Raspberry Pi

Tested under QEMU.

Instructions:

1. Build u-boot
   1. Download aarch64 toolchain and u-boot source
   2. make rpi_3_defconfig ARCH=arm CROSS_COMPILE=aarch64-elf-
   3. make all ARCH=arm CROSS_COMILE=aarch64-elf-
   4. A file named u-boot.bin should be generated
2. Use u-boot to run rCore
   1. make run arch=aarch64 u_boot=/path/to/u-boot.bin
   2. In u-boot, enter following commands:
      1. mmc read 0x1000000 0 ${nblocks}, where ${nblocks} can be probed if you enter a large enought number
      2. bootelf -p 0x1000000
   3. rCore should boot now