an executable image from various boot devices.
The Gateworks Ventana board config uses an SPL build configuration. This
-will build the following artifacts from u-boot source:
+will build the following artifacts from U-Boot source:
- SPL - Secondary Program Loader that the i.MX6 BOOT ROM (Primary Program
Loader) boots. This detects CPU/DRAM configuration, configures
The DRAM controller, loads u-boot.img from the detected boot device,
and jumps to it. As this is booted from the PPL, it has an IVT/DCD
table.
- - u-boot.img - The main u-boot core which is u-boot.bin with a image header.
+ - u-boot.img - The main U-Boot core which is u-boot.bin with a image header.
2. Build
The kobs-ng application uses an imximage which contains the Image Vector Table
(IVT) and Device Configuration Data (DCD) structures that the i.MX6 BOOT ROM
requires to boot. The kobs-ng adds the Firmware Configuration Block (FCB) and
-Discovered Bad Block Table (DBBT). The SPL build artifact from u-boot is
+Discovered Bad Block Table (DBBT). The SPL build artifact from U-Boot is
an imximage.
-The u-boot.img, which is the non SPL u-boot binary appended to a u-boot image
+The u-boot.img, which is the non SPL U-Boot binary appended to a U-Boot image
header must be programmed in the NAND flash boot device at an offset hard
coded in the SPL. For the Ventana boards, this has been chosen to be 14MB.
-The image can be programmed from either u-boot or Linux:
+The image can be programmed from either U-Boot or Linux:
-u-boot:
+U-Boot:
Ventana > setenv mtdparts mtdparts=nand:14m(spl),2m(uboot),1m(env),-(rootfs)
Ventana > tftp ${loadaddr} u-boot.img && nand erase.part uboot && \
nand write ${loadaddr} uboot ${filesize}
When the IMX6 eFUSE settings have been factory programmed to boot from
micro-SD the SPL will be loaded from offset 0x400 (1KB). Once the SPL is
-booted, it will load and execute U-boot (u-boot.img) from offset 69KB
+booted, it will load and execute U-Boot (u-boot.img) from offset 69KB
on the micro-SD (defined by CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR).
While it is technically possible to enable the SPL to be able to load
The SPL decides to boot either U-Boot (u-boot.img) or the OS (args + kernel)
based on the return value of the spl_start_uboot() function. While often
this can simply be the state of a GPIO based pushbutton or DIP switch, for
-Gateworks Ventana, we use the U-Boot environment 'boot_os' variable which if
-set to '1' will choose to boot the OS rather than U-Boot. While the choice
-of adding env support to the SPL adds a little bit of time to the boot
-process as well as (significant really) SPL code space this was deemed most
-flexible as within the large variety of Gateworks Ventana boards not all of
-them have a user pushbutton and that pushbutton may be configured as a hard
-reset per user configuration.
+Gateworks Ventana, we use an EEPROM register on i2c-0 at 0x50:0x00:
+set to '0' will choose to boot to U-Boot and otherwise it will boot to OS.
To use Falcon mode it is required that you first 'prepare' the 'args' data
that is stored on your boot medium along with the kernel (which can be any
# flash args (at 17MB)
Ventana > nand erase.part args && nand write 18000000 args 100000
- # set boot_os env var to enable booting to Linux
- Ventana > setenv boot_os 1 && saveenv
+ # set i2c register 0x50:0x00=0 to boot to Linux
+ Ventana > i2c dev 0 && i2c mw 0x50 0x00.0 0 1
Be sure to adjust 'bootargs' above to your OS needs (this will be different
for various distros such as OpenWrt, Yocto, Android, etc). You can use the
# write args 1MB data (0x800 sectors) to 1MB offset (0x800 sectors)
Ventana > mmc write 18000000 0x800 0x800
- # set boot_os to enable falcon mode
- Ventana > setenv boot_os 1 && saveenv
+ # set i2c register 0x50:0x00=0 to boot to Linux
+ Ventana > i2c dev 0 && i2c mw 0x50 0x00.0 0 1
Be sure to adjust 'bootargs' above to your OS needs (this will be different
for various distros such as OpenWrt, Yocto, Android, etc). You can use the
projects / oweals / u-boot.git / blobdiff