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White Rabbit Switch - Software
Commit 553d6a91 authored by Alessandro Rubini's avatar Alessandro Rubini
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doc: wrboot part is filled

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doc/wrs-build.in
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......@@ -702,7 +702,10 @@ The individual menu items perform the following actions:
This fires the editor on the configuration file, and
saves it to flash when the user is done. This is useful to
change the MAC address of the ARM network port.
change the MAC address of the ARM network port. Please note
that saving save the whole @file{/env} file tree, so you
can also change the init scripts interactively and have them
stored persistently on the flash.
@item 4: exit to shell
......@@ -724,153 +727,42 @@ The individual menu items perform the following actions:
@node Using wrboot
@section Using wrboot
If you use the @i{wrboot} script option, you can for example run
an NFS-Root system using a script similar to the one included
in the @file{binaries} directory of this package. Even though
the directory is called @file{binaries} the file
is ASCII anyways).
@c FIXME: wrboot ``binary''
dhcpd: DHCPOFFER on 192.168.16.224 to 02:0b:ad:c0:ff:ee via eth0
atftpd[5623]: Serving wrboot-02:0B:AD:C0:FF:EE to 192.168.16.224:1029
atftpd[5623]: Serving 192.168.16.224/wrboot to 192.168.16.224:1030
atftpd[5623]: Serving wrboot to 192.168.16.224:1031
an NFS-Root system or do whatever customization and testing you want.
The provided procedure tries to load the script from TFTP under three
different names, from most specific to most generic, and the first
match will be used. The first name is MAC-address-based, the
second is IP-address-based and the third is just @file{wrboot}.
The boot loader tries to download three files, in this order:
``@code{wrboot-MA:CA:DD:RR:EE:SS}'',
``@code{192.168.from.dhcp/wrboot}'', ``@code{wrboot}''. If no such
file is found, the menu is re-entered.
This is for example what I see in my logs when only providing @file{wrboot}:
@smallexample
dhcpd: DHCPOFFER on 192.168.16.224 to 02:0b:ad:c0:ff:ee via eth0
atftpd[5623]: Serving wrboot-02:0B:AD:C0:FF:EE to 192.168.16.224:1029
atftpd[5623]: Serving 192.168.16.224/wrboot to 192.168.16.224:1030
atftpd[5623]: Serving wrboot to 192.168.16.224:1031
mountd[21014]: NFS mount of /tftpboot/192.168.16.9 attempted from 192.168.16.9
@end smallexample
Assuming you have a known-working NFS-Root installation, in the
usual directory of your server,
standard a TFTP
server and you don't use the DHCP server; you can write a @file{wrboot}
script to boot the Linux kernel loaded with TFTP and the file system on NFS.
Following an example of a @file{wrboot} script used too boot from NFS.
@example
eth0.ipaddr=192.168.16.9
eth0.serverip=192.168.16.1
addpart /dev/mem 0x400000@@0x71000000(kernel)
tftp zImage /dev/mem.kernel
bootargs="$bootargs mem=64m root=nfs nfsroot=/opt/root/wrs,tcp "
bootargs="$bootargs ip=192.168.16.9:192.168.16.1:255.255.255.0"
bootz /dev/mem.kernel
@end example
As described above, by using the @i{boot from script} option, barebox
automatically load your @file{wrboot} script @footnote{See
@ref{Booting with Barebox} to know where place your @file{wrboot}}.
@c FIXME: remove this one
@example
# dmesg | grep -i mtd
Creating 2 MTD partitions on "atmel_nand":
mtd_dataflash spi0.0: AT45DB642x (8448 KBytes) pagesize 1056 bytes (OTP)
# cat /proc/mtd
dev: size erasesize name
mtd0: 04000000 00020000 "Partition 1"
mtd1: 1c000000 00020000 "Partition 2"
mtd2: 00840000 00000420 "spi0.0-AT45DB642x"
# dmesg | grep -i bad
Scanning device for bad blocks
Bad eraseblock 2 at 0x000000040000
Bad eraseblock 914 at 0x000007240000
Bad eraseblock 2649 at 0x000014b20000
Bad eraseblock 2944 at 0x000017000000
@end example
To set up a boot procedure that doesn't depend on the network,
we need to choose where the place the kernel and filesystem. To
avoid repartitioning the NAND memory let's use the two
partitions we have: mtd0 to fit the kernel and mtd1 for the filesystem.
Please note that the environment of @i{barebox} is stored in NAND
memory from 256k to 512k. The size is so big because @i{barebox}
will skip badblocks within that are.
We chose to place the IP-address-based name in a subdirectory because
this is the default place where the NFS-Root filesystem is mounted
from, as shown in the log excerpt above. So you'll have your
@file{wrboot} in the same place
The suggested setup, thus, is the following:
The @file{binaries} subdirectory of this package includes two known-working
wrboot scripts as examples; one if for use with static IP addresses and
the other relies on DHCP. If you want to override the default NFS-Root
directory mounted from the server (which is @code{/tftpboot/<ip-address>})
you can add something like the following line to your @file{wrboot} script:
@example
0x0000.0000 - 0x0004.0000 Empty (space for a barebox)
0x0004.0000 - 0x0008.0000 Barebox environment
0x0008.0000 - 0x0010.0000 Empty (up to 1MB)
0x0010.0000 - 0x0090.0000 Kernel (plenty of space)
0x0090.0000 - 0x0400.0000 Empty (up to the end of /dev/mtd0)
0x0400.0000 - 0x2000.0000 Filesystem space, jffs2
bootargs="$bootargs nfsroot=/opt/root/wrs-3"
@end example
With this in mind, the installation procedure is as follow:
@table @i
@item Erase the filesystem partion if needed
@code{flash_eraseall -j /dev/mtd1}
@item Mount as @i{jffs2}
@code{mount -t jffs2 /dev/mtdblock1 /mnt}
@item Copy your filesystem data, possibly from the cpio archive
@code{cd /mnt; zcat /tmp2/wrs-image.cpio.gz | cpio --extract}
Here, you may want to copy the current NFS-Root filesystem,
but the @i{cp} command we have on the target lacks the
@code{-x} (@code{--one-file-system}) option.
@item Umount the filesystem
@code{cd /; umount /mnt}
@item Erase space for the kernel
@code{flash_erase /dev/mtd0 0x100000 0x40}
Note that the offset is in bytes (1MB) and the lenght is in
number of blocks (each block is 128kB
@item Copy the kernel to nand
@code{cat /path/to/zImage /dev/zero | cat | dd bs=1k count=2048 > /tmp/k}
@code{dd if=/tmp/k bs=128k of=/dev/mtd0 seek=8}
The former command is needed to pad the kernel to a multiple
of 128kB, as the flash has 128k-sized blocks. The size here
is 2MB, which is more than enough for our current kernel.
The latter command copies to @code{/dev/mtd0} as offset 1MB.
@end table
The following repeats the commands in a format that is simpler to cut
and paste to your serial port:
@smallexample
flash_eraseall -j /dev/mtd1
mount -t jffs2 /dev/mtdblock1 /mnt
cd /mnt; zcat /tmp2/wrs-image.cpio.gz | cpio --extract
cd /; umount /mnt
flash_erase /dev/mtd0 0x100000 0x40
cat /path/to/zImage /dev/zero | cat | dd bs=1k count=2048 > /tmp/k
dd if=/tmp/k bs=128k of=/dev/mtd0 seek=8
@end smallexample
Now, we need to go to @i{barebox} and change the default boot command.
To do it, you need to call @code{edit /env/config} and later
@code{saveenv}. The internal editor of @i{barebox} is pretty basic, but
it use the arrow keys (it is not like @i{vi}, for your pleasure but
not for mine). To save and exit use @i{ctrl-D}.
IF you use static IP addresses, please note that you should fix
@file{/etc/init.d/S40network} in the filesystem for your switch,
so it doesn't run the DHCP client.
@c ##########################################################################
@node The Individual Build Steps
......
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