mirror of
https://source.denx.de/u-boot/u-boot.git
synced 2025-10-26 05:51:29 +01:00
3e584b94d2
on the shc board we see when booting in net boot mode, that the ROM bootloader sends "AM335x ROM" as vendor-class-identifier. U-Boots doc says "DM814x ROM". So, add the info to the doc, that there is also "AM335x ROM" possible. Signed-off-by: Heiko Schocher <hs@denx.de> Reviewed-by: Tom Rini <trini@konsulko.com>
97 lines
4.4 KiB
Plaintext
97 lines
4.4 KiB
Plaintext
USING AM335x NETBOOT FEATURE
|
|
|
|
Some boards (like TI AM335x based ones) have quite big on-chip RAM and
|
|
have support for booting via network in ROM. The following describes
|
|
how to setup network booting and then optionally use this support to flash
|
|
NAND and bricked (empty) board with only a network cable.
|
|
|
|
I. Building the required images
|
|
1. You have to enable generic SPL configuration options (see
|
|
doc/README.SPL) as well as CONFIG_SPL_NET_SUPPORT,
|
|
CONFIG_ETH_SUPPORT, CONFIG_SPL_LIBGENERIC_SUPPORT and
|
|
CONFIG_SPL_LIBCOMMON_SUPPORT in your board configuration file to build
|
|
SPL with support for booting over the network. Also you have to enable
|
|
the driver for the NIC used and CONFIG_SPL_BOARD_INIT option if your
|
|
board needs some board-specific initialization (TI AM335x EVM does).
|
|
If you want SPL to use some Vendor Class Identifier (VCI) you can set
|
|
one with CONFIG_SPL_NET_VCI_STRING option. am335x_evm configuration
|
|
comes with support for network booting preconfigured.
|
|
2. Define CONFIG_BOOTCOMMAND for your board to load and run debrick
|
|
script after boot:
|
|
#define CONFIG_BOOTCOMMAND \
|
|
"setenv autoload no; " \
|
|
"bootp; " \
|
|
"if tftp 80000000 debrick.scr; then " \
|
|
"source 80000000; " \
|
|
"fi"
|
|
(Or create additional board configuration with such option).
|
|
3. Build U-Boot as usual
|
|
$ make <your_board_name>
|
|
You will need u-boot.img and spl/u-boot.bin images to perform
|
|
network boot. Copy them to u-boot-restore.img and
|
|
u-boot-spl-restore.bin respectively to distinguish this version
|
|
(with automatic restore running) from the main one.
|
|
|
|
II. Host configuration.
|
|
1. Setup DHCP server (recommended server is ISC DHCPd).
|
|
- Install DHCP server and setup it to listen on the interface you
|
|
chose to connect to the board (usually configured in
|
|
/etc/default/dhcpd or /etc/default/isc-dhcp-server). Make sure there
|
|
are no other active DHCP servers in the same network segment.
|
|
- Edit your dhcpd.conf and subnet declaration matching the address
|
|
on the interface. Specify the range of assigned addresses and bootfile
|
|
to use. IMPORTANT! Both RBL and SPL use the image filename provided
|
|
in the BOOTP reply but obviously they need different images (RBL needs
|
|
raw SPL image -- u-boot-spl-restore.bin while SPL needs main U-Boot
|
|
image -- u-boot-restore.img). So you have to configure DHCP server to
|
|
provide different image filenames to RBL and SPL (and possibly another
|
|
one to main U-Boot). This can be done by checking Vendor Class
|
|
Identifier (VCI) set by BOOTP client (RBL sets VCI to "DM814x ROM v1.0"
|
|
and you can set VCI used by SPL with CONFIG_SPL_NET_VCI_STRING option,
|
|
see above).
|
|
- If you plan to use TFTP server on another machine you have to set
|
|
server-name option to point to it.
|
|
- Here is sample configuration for ISC DHCPd, assuming the interface
|
|
used to connect to the board is eth0, and it has address 192.168.8.1:
|
|
|
|
subnet 192.168.8.0 netmask 255.255.255.0 {
|
|
range dynamic-bootp 192.168.8.100 192.168.8.199;
|
|
|
|
if substring (option vendor-class-identifier, 0, 10) = "DM814x ROM" {
|
|
filename "u-boot-spl-restore.bin";
|
|
} elsif substring (option vendor-class-identifier, 0, 17) = "AM335x U-Boot SPL" {
|
|
filename "u-boot-restore.img";
|
|
} else {
|
|
filename "uImage";
|
|
}
|
|
}
|
|
|
|
May the ROM bootloader sends another "vendor-class-identifier"
|
|
on the shc board with an AM335X it is:
|
|
"AM335x ROM"
|
|
|
|
2. Setup TFTP server.
|
|
Install TFTP server and put image files to it's root directory
|
|
(likely /tftpboot or /var/lib/tftpboot or /srv/tftp). You will need
|
|
u-boot.img and spl/u-boot-spl-bin files from U-Boot build directory.
|
|
|
|
III. Reflashing (debricking) the board.
|
|
1. Write debrick script. You will need to write a script that will
|
|
be executed after network boot to perform actual rescue actions. You
|
|
can use usual U-Boot commands from this script: tftp to load additional
|
|
files, nand erase/nand write to erase/write the NAND flash.
|
|
|
|
2. Create script image from your script. From U-Boot build directory:
|
|
|
|
$ ./tools/mkimage -A arm -O U-Boot -C none -T script -d <your script> debrick.scr
|
|
|
|
This will create debrick.scr file with your script inside.
|
|
|
|
3. Copy debrick.scr to TFTP root directory. You also need to copy
|
|
there all the files your script tries to load via TFTP. Example script
|
|
loads u-boot.img and MLO. You have to create these files doing regular
|
|
(not restore_flash) build and copy them to tftpboot directory.
|
|
|
|
4. Boot the board from the network, U-Boot will load debrick script
|
|
and run it after boot.
|