flash/nor: add support for NXP QN908x

This patch adds support for the NXP QN908x family of Bluetooth
microcontrollers, such as the QN9080. This chip features a Cortex-M4F
with 512 KiB of flash on all the available versions, although the
documentation suggests that there might be 256 kB versions as well.

The initial support allows to read, erase and write the whole user flash
area. Three new sub-commands under the new "qn908x" command are added
in this patch as well: disable_wdog to disabled the watchdog,
mass_erase to perform a mass erase and allow_brick to allow programming
images that disable the SWD interface.

Disabling the watchdog is required after a "reset halt" in order to run
the CRC algorithm from RAM when verifying the chip. However, this is not
done automatically on probing or other initialization since disabling
the watchdog might interfere with debugging real applications.

The "mass_erase" command allows to erase the whole flash without
probing it, since in some scenarios the chip can be locked such that no
flash or ram can be accessed from the SWD interface, allowing only to
run a mass_erase to be able to flash the program.

The flashing process allows to compute a checksum, similar to the
lpc2000 driver "calc_checksum" but done over a different region of the
memory. This checksum is required to be present for the QN908x
bootloader ROM to boot, and otherwise is useless. As with the lpc2000
design, verification when using "calc_checksum" is expected to fail if
the checksum was not valid in the image being verified.

This was manually tested on a QN9080, including the scan-view,
AddressSanitizer/UBSan and test coverage configurations.

Change-Id: Ibd6d8f3608654294795085fcaaffb448b77cc58b
Co-developed-by: Marian Buschsieweke <marian.buschsieweke@ovgu.de>
Signed-off-by: Marian Buschsieweke <marian.buschsieweke@ovgu.de>
Signed-off-by: iosabi <iosabi@protonmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/5584
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

0 files changed, 0 insertions, 0 deletions