A Simple Bootloader for S5P6818

This bootloader is a light-weight version for loading other full-featured bootloaders (such as U-boot) or bare-metal programs. For now, it has been built for and tested under FriendlyARM NanoPi M3 in AArch64 mode.

Supported Features

Board-level initialization, including PMIC, DDR3, slave CPU and SoC partials.
Loading and running binary code from USB or SD card with FAT12/FAT16 File Systems.

SDFS boot

For official bootloader I find, SD boot only means that booting from bare sectors from SD card starting at Sector 1, and SDFS boot is actually not supported. If you have had it for a long time, let's try to use this bootloader (Actually it's an important reason to build this project); now it can identify the first partition, check the volume label (optioned), load the configuration file, and finally load binary code. Considering about reality, the bootloader can only identify FAT12/FAT16, but it's pratical enough, because FAT16 can support 2048 bytes/cluster * 65525 cluster (of course larger cluster), approximately 128 MBytes. The Configuration file is like this:

filename=u-boot.bin
load_addr=0x43c00000
launch_addr=0x43c00000

And the default value can be changed by modifying Board-specified header. Noticing that the configuration file and binary code should be put in the root directory.

USB boot

If SDFS boot fails, the bootloader will try USB boot. In that case, USB boot is similiar with that in ROM code (called iROMBOOT). You can learn more information from S5P6818 Datasheet. This bootloader will retry until USB boot is successful. In Version v1.1, the bootloader supports loading binary code without executing it when USB booting, just settings launch_addr to 0. In that case, DfuSe-like tool can be used to load Linux kernel first, then load U-boot and boot from U-boot to Linux. It will be convenient for kernel developers.

Known problems

Sometimes this bootloader may be stuck in SD boot when powered up first time. It seems a general problems under my dev-board, and it also occurs when I use official bootloader (called Nexell SecondBoot or 2ndboot). It's easy to be solved, just poping up and inserting the SD card.

Makefile

You can use make, make install, make clean to handle the bootloader project. By the way, make install use USB to boot this bootloader, and you may need to install libusb-1.0 libraries and use root permission.

Some parameters can be used for make.

CROSS_COMPILE

Cross-compiling toolchain can be specified using CROSS_COMPILE=toolchain_path.

DEBUG

If debug information is needed, just using DEBUG=1 and rebuilding the project.

V

Using V=1 to output more compiling message.

Change Logs

Version: v1.2
--- Update time: 02/12/2017
--- Description: Adds configurations of TrustZone and GIC

Version: v1.1
--- Update time: 02/09/2017
--- Description: Supports loading binary code without executing it

Version: v1.0
--- Update time: 02/07/2017
--- Description: First build

File Tree

.
├── config.mk
├── driver
│   ├── arm
│   │   ├── bp_147.h
│   │   ├── cci_400.h
│   │   ├── gic_400.h
│   │   └── tzc_380.h
│   ├── Makefile
│   ├── nexell
│   │   ├── Makefile
│   │   ├── nx_alive.c
│   │   ├── nx_alive.h
│   │   ├── nx_clkgen.c
│   │   ├── nx_clkgen.h
│   │   ├── nx_ddrphy.h
│   │   ├── nx_drex.h
│   │   ├── nx_gpio.c
│   │   ├── nx_gpio.h
│   │   ├── nx_iprst.c
│   │   ├── nx_iprst.h
│   │   ├── nx_sdmmc.c
│   │   ├── nx_sdmmc.h
│   │   ├── nx_serial.c
│   │   ├── nx_serial.h
│   │   ├── nx_sysctrl.h
│   │   ├── nx_tieoff.h
│   │   ├── nx_timer.c
│   │   ├── nx_timer.h
│   │   ├── nx_tzasc.h
│   │   └── nx_usb_otg.h
│   └── x-powers
│       └── axp228.h
├── include
│   ├── common.h
│   ├── io.h
│   ├── nanopi_m3.h
│   ├── s5p6818.h
│   ├── sd.h
│   └── usb.h
├── lib
│   ├── fs
│   │   ├── fat.c
│   │   ├── fat.h
│   │   └── Makefile
│   ├── Makefile
│   └── std
│       ├── ctype.h
│       ├── debug.h
│       ├── Makefile
│       ├── math.c
│       ├── math.h
│       ├── printf.c
│       ├── printf.h
│       ├── string.c
│       └── string.h
├── LICENSE
├── Makefile
├── Makefile.build
├── README.md
├── s5p6818_aarch64.lds
├── src
│   ├── boot.c
│   ├── boot.h
│   ├── bus.c
│   ├── bus.h
│   ├── clkgen.c
│   ├── clkgen.h
│   ├── clksrc.c
│   ├── clksrc.h
│   ├── ddr3.c
│   ├── ddr3.h
│   ├── drex.c
│   ├── drex.h
│   ├── gic.c
│   ├── gic.h
│   ├── i2c.c
│   ├── i2c.h
│   ├── led.c
│   ├── led.h
│   ├── Makefile
│   ├── pmic.c
│   ├── pmic.h
│   ├── sdfsboot.c
│   ├── sdfsboot.h
│   ├── sdmmc.c
│   ├── sdmmc.h
│   ├── serial.c
│   ├── serial.h
│   ├── start_aarch64.S
│   ├── timer.c
│   ├── timer.h
│   ├── trustzone.c
│   ├── trustzone.h
│   ├── usbboot.c
│   └── usbboot.h
└── tools
    ├── build
    ├── load
    └── nsih.bin

metro94/s5p6818_bootloader