xref: /openbmc/u-boot/board/logicpd/omap3som/README (revision 3ebd892f)
1Summary
2=======
3
4The source for omap3som encompases the DM3730 SOM-LV and DM3730 Torpedo platforms.
5
6By default, the Torpedo Device Tree is integrated into U-Boot,but the MMC controller, GPIO and I2C controllers are the same, so for the purposes of loading U-Boot, it should be sufficient.  However this will display the Model as "LogicPD Zoom DM3730 Torpedo + Wireless Development Kit" upon boot.
7
8The actual board remains autodetected and the Board will read "DM37xx SOM LV" when used on the DM37 SOM-LV.  The device tree loaded with Linux is also correct.
9
10Integrating the SOM-LV Device Tree into U-Boot
11==============================================
12
13This step is optional, but should you want to change the default to the SOM-LV, locate the configs/omap3_logic_defconfig file and make the following change.
14
15  CONFIG_DEFAULT_DEVICE_TREE="logicpd-som-lv-37xx-devkit"
16
17  make distclean
18  make omap3_logic_defconfig
19
20Falcon Mode: FAT SD cards
21=========================
22
23In this case the additional file is written to the filesystem.  In this
24example we assume that the uImage and device tree to be used are already on
25the FAT filesystem (only the uImage MUST be for this to function
26afterwards) along with a Falcon Mode aware MLO and the FAT partition has
27already been created and marked bootable:
28
29U-Boot # mmc rescan
30# Load kernel and device tree into memory, perform export
31U-Boot # fatload mmc 0 ${loadaddr} uImage
32U-Boot # run loadfdt
33U-Boot # setenv optargs quiet
34U-Boot # run mmcargs
35U-Boot # run common_bootargs
36U-Boot # spl export fdt ${loadaddr} - ${fdtaddr}
37
38This will print a number of lines and then end with something like:
39   Loading Device Tree to 8dec9000, end 8dee0295 ... OK
40
41So then note the starting address and write the args to mmc/sd:
42
43U-Boot # fatwrite mmc 0:1 0x8dec9000 args 0x20000
44
45The size of 0x20000 matches the CMD_SPL_WRITE_SIZE.
46
47Falcon Mode: NAND
48=================
49
50In this case the additional data is written to another partition of the
51NAND.  In this example we assume that the uImage and device tree to be are
52already located on the NAND somewhere (such as filesystem or mtd partition)
53along with a Falcon Mode aware MLO written to the correct locations for
54booting and mtdparts have been configured correctly for the board:
55
56U-Boot # nand read ${loadaddr} kernel
57U-Boot # load nand rootfs ${fdtaddr} /boot/am335x-evm.dtb
58U-Boot # run nandargs
59U-Boot # run common_bootargs
60U-Boot # spl export fdt ${loadaddr} - ${fdtaddr}
61U-Boot # nand erase.part u-boot-spl-os
62U-Boot # nand write ${fdtaddr} u-boot-spl-os
63