The bootloader U-Boot
From IGEP - ISEE Wiki
Contents
Overview
This page is meant to be a starting point for people to learn build a u-boot image and show to people the current status of different u-boot versions for IGEP Processor Boards.
What is U-Boot?
Das U-Boot (Universal Bootloader) is an open source, primary boot loader used in embedded devices. Its primary purpose in the shipping system is to load some operating system.
That means that U-Boot is necessary to perform a certain task, but it's nothing you want to throw any significant resources at. Typically U-Boot is stored in relatively small NOR flash memory, which is expensive compared to the much larger NAND devices often used to store the operating system and the application.
Necessary package
In order to compile the u-boot it is necessary to set up the Cross Compiler correctly. In this post it is detailed how to set up correctly the Cross Compiler (and the desired version).
Download U-Boot Source
First of all, will be a distintion between NXP-processors products and ARM-processors products. Because there are different kinds of U-Boot depending of each processor.
| Commercial Name | U-Boot Series |
|---|---|
| IGEPv2 DM3730 | U-boot-ARM |
| IGEP COM MODULE DM3730/AM3703 | U-boot-ARM |
| IGEP COM AQUILA AM335x | U-boot-ARM |
| IGEPv5 OMAP5432 | U-boot-ARM |
| IGEP SMARC AM335x | U-boot-ARM |
| IGEP SMARC iMX6 | U-boot-Freescale-NXP |
- Once we know which U-Boot have we will clone the corresponding git repository.
U-Boot ARM Series
- If we have an ARM series we will follow this table to get our source of U-Boot
| Downloading binary files/U-Boot Source | |
|---|---|
| Clone the u-boot repository |
Clone the u-boot repository using git address:
or |
| Checkout u-boot repository |
Go to the u-boot-arm directory and checkout the isee_v2017.03 as:
|
U-Boot Freescale-NXP Serie
- If we have an Freescale-NXP series we will follow this table to get our source of U-Boot
| Downloading binary files/U-Boot Source | |
|---|---|
| Clone the u-boot repository |
Clone the u-boot repository using git address:
or |
| Checkout u-boot repository |
Go to the u-boot-imx directory and checkout the isee_imx_v2017.03.y as:
|
Prepare your U-BOOT
Once we have downloaded the U-Boot source. We will execute the file called defconfig (default configuration) that it variates in function of each model.
In order to load the default configuration of the target board, we have to write the following command:
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- [your_defconfig]
- In the following table it can be found the name of each default configuration associated to each IGEP PROCESSORS BOARDS:
| Module | Defconfig | Example |
|---|---|---|
| IGEPv2 DM3730 | igep0020_defconfig | make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- igep0020_defconfig
|
| IGEP COM MODULE DM3730/AM3703 | igep0030_defconfig | make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- igep0030_defconfig
|
| IGEP COM AQUILA AM335x |
am335x_igep0033_defconfig |
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- am335x_igep0033_defconfig
|
| IGEPv5 OMAP5432 | make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-
| |
| IGEP SMARC AM335x | am335x_igep0034_defconfig | make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- am335x_igep0034_defconfig
|
| IGEP SMARC iMX6 Solo/Dual Lite | igep0046_imx6dl_2G_defconfig | make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- igep0046_imx6dl_2G_defconfig
|
| IGEP SMARC iMX6 Dual/ Quad | igep0046_imx6q_2G_defconfig | make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- igep0046_imx6q_2G_defconfig
|
Build your U-BOOT
After running the defconfig. You can build the U-Boot by executing this command:
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-
Once the compile process has sucesfully finished, we will find the resulting files inside the u-boot root folder. Depending on the processor the generated files will be different:
- The result for ARM processor based board will be a MLO and u-boot.img.
- The result for Freescale-NXP processor based will be a u-boot.imx.
Finally we can copy this file in a boot device, for example, a microSD Memory Card and power on the board.
|
In case of the Freescale-NXP Porcessor Boards, it is not possible to copy directly the u-boot.imx file. It is necessary to copy in the first blocks of the boot device using the dd command. It is explained in the following link. |
What next...
After build u-boot you can use it for boot the board, exist several options for boot, check the Hardware Reference Manual about the options available for your board.
- Boot from MicroSD Card.
- Boot from NAND/eMMC flash.
u-boot Freescale-NXP iMX6 series
u-boot Texas Instruments AM335x, OMAP3, DM3730, OMAP5432 series
