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

Provided by: u-boot-tools_2022.07+dfsg-1ubuntu4_amd64

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, Avanta, 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.

-b Do only handshake on TTY without uploading any file. File upload could be done
later via option -D or via any other Xmodem application, like sx(1).

-d Do special handshake on TTY for console debug mode.

This will instruct BootROM to enter builtin simple console debug mode. Should be
combined with option -t.

To get a BootROM help, type this command followed by ENTER key:

Armada 38x BootROM has a bug which cause that BootROM's standard output is turned
off on UART when SPI-NOR contains valid boot image. Nevertheless BootROM's standard
input and BootROM's terminal echo are active and working fine. To workaround this
BootROM bug with standard output, it is possible to manually overwrite BootROM
variables stored in SRAM which BootROM use for checking if standard output is
enabled or not. To enable BootROM standard output on UART, type this command
followed by ENTER key:

w 0x40034100 1

-D image
Upload file image over TTY without initial handshake.

This method is used primary on Dove platforms, where BootROM does not support
initial handshake for entering UART upload mode and strapping pins (exported via
e.g. buttons) are used instead.

-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.

-q Obsolete. Does nothing.

It is unknown whether it did something in the past.

-s response-timeout
Specify custom response timeout when doing handshake. Default value is 50 ms. It
is the timeout between sending two consecutive handshake patterns, meaning how long
to wait for response from BootROM. Affects only option -b with image file and
option -d.

Option -a specify response timeout suitable for Armada XP BootROM and currently it
is 1000 ms.

Some testing showed that specifying 24 ms as response timeout make handshake with
Armada 385 BootROM more stable.

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

If used in combination with -b, -D or -d option, terminal mode is entered
immediately following a successful image upload or successful handshake (if not
doing 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.

EXAMPLES

       Instruct BootROM to enter boot Xmodem boot mode, send  u-boot-spl.kwb  kwbimage  file  via
       Xmodem on /dev/ttyUSB0 at 115200 Bd and run terminal program:

              kwboot -b u-boot-spl.kwb -t /dev/ttyUSB0

       Instruct  BootROM  to  enter boot Xmodem boot mode, send header of u-boot-spl.kwb kwbimage
       file via Xmodem at 115200 Bd, then instruct BootROM to change baudrate to 5200000 Bd, send
       data part of the kwbimage file via Xmodem at high speed and finally run terminal program:

              kwboot -b u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0

       Only send u-boot-spl.kwb kwbimage file via Xmodem on /dev/ttyUSB0 at 115200 Bd:

              kwboot -D u-boot-spl.kwb /dev/ttyUSB0

       Instruct  BootROM  to enter console debug mode and run terminal program on /dev/ttyUSB0 at
       115200 Bd:

              kwboot -d -t /dev/ttyUSB0

       Only run terminal program on /dev/ttyUSB0 at 115200 Bd:

              kwboot -t /dev/ttyUSB0

AUTHORS