diff options
| author | David Lechner <david@lechnology.com> | 2018-05-19 23:25:07 -0500 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2018-06-05 10:33:57 -0400 |
| commit | f203a479e7415b539ebcf766591eeafaf481814d (patch) | |
| tree | 9f03791b322dba0f76c23c320532af9cf3232af3 /board/lego/ev3/README | |
| parent | 71eb63e7ee10299e1edfbdfcec21592de6953d62 (diff) | |
ARM: legoev3: update boot script to load uEnv.txt and .dtb
This updates the LEGO MINDSTORMS EV3 boot script to try loading a
uEnv.txt file and a da850-lego-ev3.dtb device tree during boot.
Signed-off-by: David Lechner <david@lechnology.com>
Diffstat (limited to 'board/lego/ev3/README')
| -rw-r--r-- | board/lego/ev3/README | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/board/lego/ev3/README b/board/lego/ev3/README index a356373249..da62a649ba 100644 --- a/board/lego/ev3/README +++ b/board/lego/ev3/README @@ -9,14 +9,34 @@ Booting ======= The EV3 contains a bootloader in EEPROM that loads u-boot.bin from address 0x0 -of the spi flash memory. Using the default configuration, u-boot will check to -see if there is a boot.scr file on the first FAT partition of the mmc. If there -is, it will run the script and boot the kernel from the uImage file also in -the FAT partition. Otherwise, it will load a kernel and rootfs from the flash. -The kernel must be stored at address 0x50000 on the flash and have a maximum -size of 4MiB. The rootfs must be a squasfs image and stored at 0x450000 in the -flash and have a maximum size of 10MiB. The flash starting at 0xE50000 is -reserved for user data. +of the SPI flash memory (with a size of 256KiB!). Because the EEPROM is read- +only and it takes care of low level configuration (PLL and DDR), we don't use +U-Boot to produce an SPL image. + +Using the default configuration, U-Boot had a boot scrips that works as follows: + +* Check to see if microSD card is present +* If it is, try to load boot.scr from the first FAT partition +* If loading boot.scr was successful, run it +* Otherwise, try loading uEnv.txt +* If loading uEnv.txt was successful, import it +* If there is a uenvcmd variable (from uEnv.txt), run it +* Try to load uImage from the first FAT partition +* If it was successful, try to load da850-lego-ev3.dtb +* If loading uImage was successful, boot it (DT is optional) +* If none of the above was successful, try booting from flash + +Suggested Flash Memory Layout +============================= + +The following is based on the default U-Boot configuration: + +| Image (file) | Start Addr. | Max. Size | ++--------------------+-------------+-------------------+ +| u-boot.bin | 0x0 | 0x40000 (256KiB) | +| da850-lego-ev3.dtb | 0x40000 | 0x10000 (64KiB) | +| uImage | 0x50000 | 0x400000 (4MiB) | +| rootfs (squashfs) | 0x450000 | 0xa00000 (10MiB) | Writing image to flash ====================== |