| .TH KWBOOT 1 "2022-03-02" |
| |
| .SH NAME |
| kwboot \- Boot Marvell Kirkwood (and others 32-bit) SoCs over a serial link. |
| .SH SYNOPSIS |
| .B kwboot |
| .RB [ "-b \fIimage\fP" ] |
| .RB [ "-t" ] |
| .RB [ "-B \fIbaudrate\fP" ] |
| .RB \fITTY\fP |
| .SH "DESCRIPTION" |
| |
| The \fBkwboot\fP 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 |
| (\fIkwbimage v0\fP or \fIv1\fP), created using a tool such as |
| \fBmkimage\fP. |
| |
| 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. |
| |
| .SH "OPTIONS" |
| |
| .TP |
| .BI "\-b \fIimage\fP" |
| Handshake; then upload file \fIimage\fP over \fITTY\fP. |
| |
| Note that for the encapsulated boot code to be executed, \fIimage\fP |
| must be of type "UART boot" (0x69). The \fBkwboot\fP program changes |
| this type automatically, unless the \fIimage\fP is signed, in which |
| case it cannot be changed. |
| |
| This mode writes handshake status and upload progress indication to |
| stdout. It is possible that \fIimage\fP 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. |
| |
| .TP |
| .B "\-b" |
| Do only handshake on \fITTY\fP without uploading any file. File upload |
| could be done later via option \fB\-D\fP or via any other Xmodem |
| application, like \fBsx\fP(1). |
| |
| .TP |
| .B "\-d" |
| Do special handshake on \fITTY\fP for console debug mode. |
| |
| This will instruct BootROM to enter builtin simple console debug mode. |
| Should be combined with option \fB\-t\fP. |
| |
| To get a BootROM help, type this command followed by ENTER key: |
| |
| .RS 1.2i |
| .TP |
| .B ? |
| .RE |
| .IP |
| |
| 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: |
| |
| .RS 1.2i |
| .TP |
| .B w 0x40034100 1 |
| .RE |
| |
| .TP |
| .BI "\-D" " image" |
| Upload file \fIimage\fP over \fITTY\fP 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. |
| |
| .TP |
| .BI "\-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. |
| |
| .TP |
| .B "\-q" |
| Obsolete. Does nothing. |
| |
| It is unknown whether it did something in the past. |
| |
| .TP |
| .BI "\-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 \fB\-b\fP with |
| image file and option \fB\-d\fP. |
| |
| Option \fB-a\fP 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. |
| |
| .TP |
| .BI "\-t" |
| Run a terminal program, connecting standard input and output to |
| .RB \fITTY\fP. |
| |
| If used in combination with \fB\-b\fP, \fB\-D\fP or \fB\-d\fP 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 \fBctrl-\e\fP followed by \fBc\fP from console input. |
| |
| .TP |
| .BI "\-B \fIbaudrate\fP" |
| If used in combination with \fB-b\fP, inject into the image header |
| code that changes baud rate to \fIbaudrate\fP 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 \fITTY\fP correspondingly. This can make the upload significantly |
| faster. |
| |
| If used in combination with \fB-t\fP, adjust the baud rate to |
| \fIbaudrate\fP on \fITTY\fP before starting terminal. |
| |
| If both \fB-b\fP and \fB-t\fP are used, the baud rate is changed |
| back to 115200 after the upload. |
| |
| Tested values for \fIbaudrate\fP for Armada 38x include: 115200, |
| 230400, 460800, 500000, 576000, 921600, 1000000, 1152000, 1500000, |
| 2000000, 2500000, 3125000, 4000000 and 5200000. |
| |
| .SH "EXAMPLES" |
| |
| Instruct BootROM to enter boot Xmodem boot mode, send \fIu-boot-with-spl.kwb\fP |
| kwbimage file via Xmodem on \fI/dev/ttyUSB0\fP at 115200 Bd and run terminal |
| program: |
| .IP |
| .B kwboot -b u-boot-with-spl.kwb -t /dev/ttyUSB0 |
| |
| .PP |
| Instruct BootROM to enter boot Xmodem boot mode, send header of |
| \fIu-boot-with-spl.kwb\fP 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, then change baudrate back to 115200 Bd, |
| and finally run terminal program: |
| .IP |
| .B kwboot -b u-boot-with-spl.kwb -B 5200000 -t /dev/ttyUSB0 |
| |
| .PP |
| Only send \fIu-boot-with-spl.kwb\fP kwbimage file via Xmodem on \fI/dev/ttyUSB0\fP |
| at 115200 Bd: |
| .IP |
| .B kwboot -D u-boot-with-spl.kwb /dev/ttyUSB0 |
| |
| .PP |
| Instruct BootROM to enter console debug mode and run terminal program on |
| \fI/dev/ttyUSB0\fP at 115200 Bd: |
| .IP |
| .B kwboot -d -t /dev/ttyUSB0 |
| |
| .PP |
| Only run terminal program on \fI/dev/ttyUSB0\fP at 115200 Bd: |
| .IP |
| .B kwboot -t /dev/ttyUSB0 |
| |
| .SH "SEE ALSO" |
| .PP |
| \fBmkimage\fP(1), \fBsx\fP(1) |
| |
| .SH "AUTHORS" |
| |
| Daniel Stodden <daniel.stodden@gmail.com> |
| .br |
| Luka Perkov <luka@openwrt.org> |
| .br |
| David Purdy <david.c.purdy@gmail.com> |
| .br |
| Pali Rohár <pali@kernel.org> |
| .br |
| Marek Behún <kabel@kernel.org> |