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>
This commit is contained in:
iosabi 2020-04-09 22:00:58 +00:00 committed by Antonio Borneo
parent 24b656bff5
commit 370bf43fb1
6 changed files with 1348 additions and 0 deletions

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@ -7341,6 +7341,116 @@ Note: only Main and Work flash regions support Erase operation.
@end deffn
@end deffn
@deffn {Flash Driver} {qn908x}
The NXP QN908x microcontrollers feature a Cortex-M4F with integrated Bluetooth
LE 5 support and an internal flash of up to 512 KiB. These chips only support
the SWD interface.
The @var{qn908x} driver uses the internal "Flash Memory Controller" block via
SWD to erase, program and read the internal flash. This driver does not
support the ISP (In-System Programming) mode which is an alternate way to
program the flash via UART, SPI or USB.
The internal flash is 512 KiB in size in all released chips and it starts at
the address 0x01000000, although it can be mapped to address 0 and it is
aliased to other addresses. This driver only recognizes the bank starting at
address 0x01000000.
The internal bootloader stored in ROM is in charge of loading and verifying
the image from flash, or enter ISP mode. The programmed image must start at
the beginning of the flash and contain a valid header and a matching CRC32
checksum. Additionally, the image header contains a "Code Read Protection"
(CRP) word which indicates whether SWD access is enabled, as well as whether
ISP mode is enabled. Therefore, it is possible to program an image that
disables SWD and ISP making it impossible to program another image in the
future through these interfaces, or even debug the current image. While this is
a valid use case for production deployments where the chips are locked down, by
default this driver doesn't allow such images that disable the SWD interface.
To program such images see the @command{qn908x allow_brick} command.
Apart from the CRP field which is located in the image header, the last page
of the flash memory contains a "Flash lock and protect" descriptor which allows
to individually protect each 2 KiB page, as well as disabling SWD access to the
flash and RAM. If this access is disabled it is not possible to read, erase or
program individual pages from the SWD interface or even access the read-only
"Flash information page" with information about the bootloader version and
flash size. However when this protection is in place, it is still possible to
mass erase the whole chip and then program a new image, for which you can use
the @command{qn908x mass_erase}.
Example:
@example
flash bank $FLASHNAME qn908x 0x01000000 0 0 0 $TARGETNAME calc_checksum
@end example
Parameters:
@itemize
@item @option{calc_checksum} optional parameter to compute the required
checksum of the first bytes in the vector table.
@quotation Note
If the checksum in the header of your image is invalid and you don't provide the
@option{calc_checksum} option the boot ROM will not boot your image and it may
render the flash inaccessible. On the other hand, if you use this option to
compute the checksum keep in mind that @command{verify_image} will fail on
those four bytes of the checksum since those bytes in the flash will have the
updated checksum.
@end quotation
@end itemize
@deffn {Command} {qn908x allow_brick}
Allow the qn908x driver to program images with a "Code Read Protection" byte
that disables the SWD access. Programming such image will cause OpenOCD to
not be able to reach the target over SWD anymore after the new image is
programmed and its configuration takes effect, e.g. after a reboot. After
executing @command{qn908x allow_brick} these images will be allowed to be
programmed when writing to the flash.
@end deffn
@deffn {Command} {qn908x disable_wdog}
Disable the watchdog timer (WDT) by resetting its CTRL field. The WDT starts
enabled after a @command{reset halt} and it doesn't run while the target is
halted. However, the verification process in this driver uses the generic
Cortex-M verification process which executes a payload in RAM and thus
requires the watchdog to be disabled before running @command{verify_image}
after a reset halt or any other condition where the watchdog is running.
Note that this is not done automatically and you must run this command in
those scenarios.
@end deffn
@deffn {Command} {qn908x mass_erase}
Erases the complete flash using the mass_erase method. Mass erase is only
allowed if enabled in the Lock Status Register 8 (LOCK_STAT_8) which is read
from the last sector of the flash on boot. However, this mass_erase lock
protection can be bypassed and this command does so automatically.
In the same LOCK_STAT_8 the flash and RAM access from SWD can be disabled by
setting two bits in this register. After a mass_erase, all the bits of the
flash would be set, making it the default to restrict SWD access to the flash
and RAM regions. This new after erase LOCK_STAT_8 value only takes effect after
being read from flash on the next reboot for example. After a mass_erase the
LOCK_STAT_8 register is changed by the hardware to allow access to flash and
RAM regardless of the value on flash, but only right after a mass_erase and
until the next boot. Therefore it is possible to perform a mass_erase, program
a new image, verify it and then reboot to a valid image that's locked from the
SWD access.
The @command{qn908x mass_erase} command clears the bits that would be loaded
from the flash into LOCK_STAT_8 after erasing the whole chip to allow SWD
access for debugging or re-flashing an image without a mass_erase by default.
If the image being programmed also programs the last page of the flash with its
own settings, this mass_erase behavior will interfere with that write since a
new erase of at least the last page would need to be performed before writing
to it again. For this reason the optional @option{keep_lock} argument can be
used to leave the flash and RAM lock set. For development environments, the
default behavior is desired.
The mass erase locking mechanism is independent from the individual page
locking bits, so it is possible that you can't erase a given page that is
locked and you can't unprotect that page because the locking bits are also
locked, but can still mass erase the whole flash.
@end deffn
@end deffn
@deffn {Flash Driver} {rp2040}
Supports RP2040 "Raspberry Pi Pico" microcontroller.
RP2040 is a dual-core device with two CM0+ cores. Both cores share the same

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@ -54,6 +54,7 @@ NOR_DRIVERS = \
%D%/psoc4.c \
%D%/psoc5lp.c \
%D%/psoc6.c \
%D%/qn908x.c \
%D%/renesas_rpchf.c \
%D%/rp2040.c \
%D%/rsl10.c \

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@ -284,6 +284,7 @@ extern const struct flash_driver psoc5lp_eeprom_flash;
extern const struct flash_driver psoc5lp_flash;
extern const struct flash_driver psoc5lp_nvl_flash;
extern const struct flash_driver psoc6_flash;
extern const struct flash_driver qn908x_flash;
extern const struct flash_driver renesas_rpchf_flash;
extern const struct flash_driver rp2040_flash;
extern const struct flash_driver rsl10_flash;

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@ -61,6 +61,7 @@ static const struct flash_driver * const flash_drivers[] = {
&psoc5lp_eeprom_flash,
&psoc5lp_nvl_flash,
&psoc6_flash,
&qn908x_flash,
&renesas_rpchf_flash,
&rp2040_flash,
&sh_qspi_flash,

1197
src/flash/nor/qn908x.c Normal file

File diff suppressed because it is too large Load Diff

38
tcl/target/qn908x.cfg Normal file
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@ -0,0 +1,38 @@
# SPDX-License-Identifier: GPL-2.0-or-later
# NXP QN908x Cortex-M4F with 128 KiB SRAM
source [find target/swj-dp.tcl]
set CHIPNAME qn908x
set CHIPSERIES qn9080
if { ![info exists WORKAREASIZE] } {
set WORKAREASIZE 0x20000
}
# SWD IDCODE (Cortex M4).
set CPUTAPID 0x2ba01477
swj_newdap $CHIPNAME cpu -irlen 4 -expected-id $CPUTAPID
dap create $CHIPNAME.dap -chain-position $CHIPNAME.cpu
set TARGETNAME $CHIPNAME.cpu
target create $TARGETNAME cortex_m -dap $CHIPNAME.dap
# SRAM is mapped at 0x04000000.
$TARGETNAME configure -work-area-phys 0x04000000 -work-area-size $WORKAREASIZE
# flash bank <name> qn908x <base> <size> 0 0 <target#> [calc_checksum]
# The base must be set as 0x01000000, and the size parameter is unused.
set FLASHNAME $CHIPNAME.flash
flash bank $FLASHNAME qn908x 0x01000000 0 0 0 $TARGETNAME calc_checksum
# We write directly to flash memory over this adapter interface. For debugging
# this could in theory be faster (the Core clock on reset is normally at 32MHz),
# but for flashing 1MHz is more reliable.
adapter speed 1000
# Delay on reset line.
adapter srst delay 200
cortex_m reset_config sysresetreq