Kontron AM4140 U-Boot Bootloader - Manual (Page 44)

U-Boot Usage AM4140 U-Boot Bootloader
Page 44 ID 1052-0281, Rev. 1.0
P R E L I M I N A R Y
6.7.2 Booting VxWorks
To boot a Wind River VxWorks image, a boot image file of the corresponding (ROM-able)
VxWorks binary image and an FDT (Flattened Device Tree) must be loaded to memory.
By default U-Boot operates on “uImage” files (boot image for U-Boot) which contain a special
header and in the data portion the operating system binary image. The special header defines
various properties of the “uImage” file (e.g. load address and entry point for the binary image
in the data portion). Both the header and the data portion of the “uImage” file are secured and
checked against corruption by a CRC32 checksum at U-Boot load time.
All VxWorks (ROM-able) binary images will be converted to a “uImage” file at build time of the
suited Wind River Workbench projects based on the dedicated Kontron VxWorks BSP (Board
Support Package). This conversion will be carried out by the “mkImage” Kontron tool, which is
automatically invoked by Wind River Workbench.
On successful build of the VxWorks binary (ROM-able) image, an additional “uImage” file con-
taining the VxWorks (ROM-able) binary image will be generated in the project default build fold-
er with the following naming conventions:
Please note that the resulting “uImage” file contains all needed information for a proper U-Boot
load process and start of the contained VxWorks binary (ROM-able) image. Therefore, it is
strongly recommended to utilize the corresponding “uImage” file listed above when using U-
Boot for booting VxWorks.
The “uImage” file and FDT are typically stored in and loaded from the SPI flash for OS.
The boot itself is initiated with the “bootm” command. To perform autobooting of a VxWorks im-
age requires that appropriate U-Boot environment variables or script(s) be defined for the boot
operation to be performed. For more detailed information with examples of boot command se-
quences, refer to the Kontron VxWorks BSP online documentation.
For more information on how to configure and build VxWorks images and how to utilize them
e.g. for a subsequent VxWorks boot process, please refer to the appropriate Wind River docu-
mentation.
U-BOOT “uImage” NAME VXWORKS IMAGE NAME
uImage.bootrom.bin bootrom.bin
uImage.vxWorks_rom.bin vxWorks_rom.bin
uImage.vxWorks_romCompress.bin vxWorks_romCompress.bin