KWBOOT(1)

NAME
kwboot - Boot Marvell Kirkwood (and others 32-bit) SoCs over a serial link.

SYNOPSIS
kwboot [-b image] [-t] [-B baudrate] TTY

DESCRIPTION

The kwboot program boots boards based on Marvell's 32-bit platforms including Kirkwood, Dove, A370, AXP, A375, A38x and A39x over their integrated UART. Boot image files will typically contain a second stage boot loader, such as U-Boot. The image file must conform to Marvell's BootROM firmware image format (kwbimage v0 or v1), created using a tool such as mkimage.

Following power-up or a system reset, system BootROM code polls the UART for a brief period of time, sensing a handshake message which initiates an image upload. This program sends this boot message until it receives a positive acknowledgement. The image is transferred using Xmodem.

Additionally, this program implements a minimal terminal mode, which can be used either standalone, or entered immediately following boot image transfer completion. This is often useful to catch early boot messages, or to manually interrupt a default boot procedure performed by the second-stage loader.

OPTIONS

-b image
    Handshake; then upload file image over TTY.

    Note that for the encapsulated boot code to be executed, image must be of type "UART boot" (0x69). The kwboot program changes this type automatically, unless the image is signed, in which case it cannot be changed.

    This mode writes handshake status and upload progress indication to stdout. It is possible that image contains an optional binary code in it's header which may also print some output via UART (for example U-Boot SPL does this). In such a case, this output is also written to stdout after the header is sent.

-p  Obsolete. Does nothing.

    In the past, when this option was used, the program patched the header in the image prior upload, to "UART boot" type. This is now done by default.

-t  Run a terminal program, connecting standard input and output to TTY.

    If used in combination with -b, terminal mode is entered immediately following a successful image upload.

    If standard I/O streams connect to a console, this mode will terminate after receiving ctrl-\ followed by c from console input.

-B baudrate
    If used in combination with -b, inject into the image header code that changes baud rate to baudrate after uploading image header, and code that changes the baud rate back to the default (115200 Bd) before executing payload, and also adjust the baud rate on TTY correspondingly. This can make the upload significantly faster.

    If used in combination with -t, adjust the baud rate to baudrate on TTY before starting terminal.

    If both -b and -t are used, the baud rate is changed back to 115200 after the upload.

    Tested values for baudrate for Armada 38x include: 115200, 230400, 460800, 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, 2500000, 3125000, 4000000 and 5200000.

SEE ALSO

mkimage(1)

AUTHORS

Daniel Stodden <daniel.stodden@gmail.com>
Luka Perkov <luka@openwrt.org>
David Purdy <david.c.purdy@gmail.com>
Pali Rohár <pali@kernel.org>
Marek Behún <marek.behun@nic.cz>