DFU flashing of apps sometimes aborts, and although rare this leads to
broken devices if no boot button or serial/jtag access exists, because
the bootloader will keep trying to start a half-flashed app that then
crashes at some point.
The easiest fix that works with existing bootloaders is to prepend a
small 512 byte stub that calculcates the crc and compares it with the
crc calculated at build time, and then either starts the actual app, or
sets the dfu flag and resets. This ensures we either have a working,
running app, or end up in the bootloader, ready to flash again.
For obvious reasons this only applies to dfu apps, and not to flash
targets like the actual bootloader itself.
Change-Id: Id6df0486c8b779889d21800dc2441b3aa9af8a5f
This bl updater can be flashed as app and will update the bootloader and
then
delete itself before resetting the sam3, so the device will end up in
the newly
updated dfu bootloader afterwards, without having to press the
bootloader button
or requring any other manual interaction, ready to receive a new
application image.
Building the blupdater requires a previously built dfu-flash bootloader
bin file that
will then be embedded into the app during building.
Related: OS#1704
Related: SYS5061
Change-Id: I53dea57bba790a2ab3245d9483e0ff1c8d19d5e3
now both partitions (bootloader and application) use a commonly
defined memory location to shared the DFU state (which includes
the magic value to know which part to start), instead of using
a hard coded value.
the bootloader size has now also been restricted to 16 kB.
this limitation is enforced so to not be able to create larger
images, which could be corrupted when flashing the application.
bootloader and application flashing have been successfully tested
on qmod st12 and st34.
Change-Id: I204bed7e9391602672ed894decec1fc12e879275
We need to refer to g_dfu as a pointer from all code. In DFU mode, it
gets assigned to the address of _g_dfu, which is placed by the linker
script at the start of RAM. In runtime mode, the pointer is statically
defined to point at the start of RAM. The linker script for the runtime
(dfu environment) is adjusted to save the first 32 bytes for the _g_dfu
structure.
This way we can easily check with 'diff' for differences in our code and
Atmel softpack. Also, this layout is more suitable for building various
different firmware images (e.g. factory-test, dfu-loader, main
application) for a variety of different boards (simtrace, owhw, qmod).
Eric Wild
Kevin Redon
Harald Welte