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stm32: flash: h50: implement bank swapping

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This commit is contained in:
Torin Cooper-Bennun 2024-04-11 15:45:04 +01:00
parent 8e850de592
commit f66b63017c
1 changed files with 47 additions and 3 deletions
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50
embassy-stm32/src/flash/h50.rs
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@ -61,9 +61,12 @@ pub(crate) unsafe fn blocking_erase_sector(sector: &FlashSector) -> Result<(), E
interrupt::free(|_| { interrupt::free(|_| {
pac::FLASH.nscr().modify(|w| { pac::FLASH.nscr().modify(|w| {
w.set_bksel(match sector.bank { // BKSEL ignores SWAP_BANK, so we must take it into account here
FlashBank::Bank1 => Bksel::BANK1, w.set_bksel(match (sector.bank, banks_swapped()) {
FlashBank::Bank2 => Bksel::BANK2, (FlashBank::Bank1, false) => Bksel::BANK1,
(FlashBank::Bank2, true) => Bksel::BANK1,
(FlashBank::Bank2, false) => Bksel::BANK2,
(FlashBank::Bank1, true) => Bksel::BANK2,
}); });
w.set_snb(sector.index_in_bank); w.set_snb(sector.index_in_bank);
w.set_ser(true); w.set_ser(true);
@ -111,6 +114,47 @@ pub(crate) unsafe fn clear_all_err() {
}) })
} }
/// Get the current SWAP_BANK option.
///
/// This value is only loaded on system or power-on reset. `perform_bank_swap()`
/// will not reflect here.
pub fn banks_swapped() -> bool {
pac::FLASH.optcr().read().swap_bank()
}
/// Logical, persistent swap of flash banks 1 and 2.
///
/// This allows the application to write a new firmware blob into bank 2, then
/// swap the banks and perform a reset, loading the new firmware.
///
/// Swap does not take effect until system or power-on reset.
///
/// PLEASE READ THE REFERENCE MANUAL - there are nuances to this feature. For
/// instance, erase commands and interrupt enables which take a flash bank as a
/// parameter ignore the swap!
pub fn perform_bank_swap() {
while busy() {}
unsafe {
clear_all_err();
}
// unlock OPTLOCK
pac::FLASH.optkeyr().write(|w| *w = 0x0819_2A3B);
pac::FLASH.optkeyr().write(|w| *w = 0x4C5D_6E7F);
while pac::FLASH.optcr().read().optlock() {}
// toggle SWAP_BANK option
pac::FLASH.optsr_prg().modify(|w| w.set_swap_bank(!banks_swapped()));
// load option bytes
pac::FLASH.optcr().modify(|w| w.set_optstrt(true));
while pac::FLASH.optcr().read().optstrt() {}
// re-lock OPTLOCK
pac::FLASH.optcr().modify(|w| w.set_optlock(true));
}
fn sr_busy(sr: Nssr) -> bool { fn sr_busy(sr: Nssr) -> bool {
// Note: RM0492 sometimes incorrectly refers to WBNE as NSWBNE // Note: RM0492 sometimes incorrectly refers to WBNE as NSWBNE
sr.bsy() || sr.dbne() || sr.wbne() sr.bsy() || sr.dbne() || sr.wbne()