This unifies the flash config to the settings used by the Boot ROM.
This makes the config unique per board which allows for changing
quad enable and status bit differences per flash device. It also
allows for timing differences due to the board layout.
This change also tweaks linker layout to leave more ram space for
the CircuitPython heap.
I have a function where it should be impossible to reach the end, so I put in a safe-mode reset at the bottom:
```
int find_unused_slot(void) {
// precondition: you already verified that a slot was available
for (int i=0; i<NUM_SLOTS; i++) {
if( slot_free(i)) {
return i;
}
}
safe_mode_reset(MICROPY_FATAL_ERROR);
}
```
However, the compiler still gave a diagnostic, because safe_mode_reset was not declared NORETURN.
So I started by teaching the compiler that reset_into_safe_mode never returned. This leads at least one level deeper due to reset_cpu needing to be a NORETURN function. Each port is a little different in this area. I also marked reset_to_bootloader as NORETURN.
Additional notes:
* stm32's reset_to_bootloader was not implemented, but now does a bare reset. Most stm32s are not fitted with uf2 bootloaders anyway.
* ditto cxd56
* esp32s2 did not implement reset_cpu at all. I used esp_restart(). (not tested)
* litex did not implement reset_cpu at all. I used reboot_ctrl_write. But notably this is what reset_to_bootloader already did, so one or the other must be incorrect (not tested). reboot_ctrl_write cannot be declared NORETURN, as it returns unless the special value 0xac is written), so a new unreachable forever-loop is added.
* cxd56's reset is via a boardctl() call which can't generically be declared NORETURN, so a new unreacahble "for(;;)" forever-loop is added.
* In several places, NVIC_SystemReset is redeclared with NORETURN applied. This is accepted just fine by gcc. I chose this as preferable to editing the multiple copies of CMSIS headers where it is normally declared.
* the stub safe_mode reset simply aborts. This is used in mpy-cross.
This is a slight trade-off with code size, in places where a "_varg"
mp_raise variant is now used. The net savings on trinket_m0 is
just 32 bytes.
It also means that the translation will include the original English
text, and cannot be translated. These are usually names of Python
types such as int, set, or dict or special values such as "inf" or
"Nan".
Since Actions passed on the previous commit, where this computed value
was checked against the specified value (if any), this is no net change,
except that we no longer need to specify it for particular boards or
ports.
I noticed that this code was referring to samd-specific functionality,
and isn't enabled except in one samd board (pewpew10). Move it.
There is incomplte support for _pew in mimxrt10xx which then caused build
errors; adding a #if guard to check for _pew being enabled fixes it.
The _pew module is not likely to be important on mimxrt but I'll leave the
choice to remove it to someone else.
* Fix flash writes that don't end on a sector boundary. Fixes#2944
* Fix enum incompatibility with IDF.
* Fix printf output so it goes out debug UART.
* Increase stack size to 8k.
* Fix sleep of less than a tick so it doesn't crash.
The iMX RT has a separate wake up controller, the GPC, that replaces
the NVIC when asleep. It adds the ability to only wake up on certain
interrupts. It seems that it requires at least one enabled interrupt
in the NVIC to turn on it's wake up circuitry. It doesn't need to
be the same interrupt as the wake up signal. For example, the RTC
in the SNVS can wake us up if a USB interrupt is enabled. Before
then it won't work. So, we enable the SNVS interrupt on start up
so it can wake us up.
