nrf/uicr: only check lowest bit.

This mirrors what nrfx does. Also it won't reboot/warn if NFCPINS is set to either
0xFFFF_FFFE or 0x0000_0000, which are all valid.
This commit is contained in:
Dario Nieuwenhuis 2023-03-07 15:28:27 +01:00
parent 18fe398673
commit 27e989afa9

View file

@ -273,28 +273,24 @@ enum WriteResult {
} }
unsafe fn uicr_write(address: *mut u32, value: u32) -> WriteResult { unsafe fn uicr_write(address: *mut u32, value: u32) -> WriteResult {
uicr_write_masked(address, value, 0xFFFF_FFFF)
}
unsafe fn uicr_write_masked(address: *mut u32, value: u32, mask: u32) -> WriteResult {
let curr_val = address.read_volatile(); let curr_val = address.read_volatile();
if curr_val == value { if curr_val & mask == value & mask {
return WriteResult::Noop; return WriteResult::Noop;
} }
// We can only change `1` bits to `0` bits. // We can only change `1` bits to `0` bits.
if curr_val & value != value { if curr_val & value & mask != value & mask {
return WriteResult::Failed; return WriteResult::Failed;
} }
// Writing to UICR can only change `1` bits to `0` bits.
// If this write would change `0` bits to `1` bits, we can't do it.
// It is only possible to do when erasing UICR, which is forbidden if
// APPROTECT is enabled.
if (!curr_val) & value != 0 {
panic!("Cannot write UICR address={:08x} value={:08x}", address as u32, value)
}
let nvmc = &*pac::NVMC::ptr(); let nvmc = &*pac::NVMC::ptr();
nvmc.config.write(|w| w.wen().wen()); nvmc.config.write(|w| w.wen().wen());
while nvmc.ready.read().ready().is_busy() {} while nvmc.ready.read().ready().is_busy() {}
address.write_volatile(value); address.write_volatile(value | !mask);
while nvmc.ready.read().ready().is_busy() {} while nvmc.ready.read().ready().is_busy() {}
nvmc.config.reset(); nvmc.config.reset();
while nvmc.ready.read().ready().is_busy() {} while nvmc.ready.read().ready().is_busy() {}
@ -393,8 +389,8 @@ pub fn init(config: config::Config) -> Peripherals {
#[cfg(any(feature = "_nrf52", feature = "_nrf5340-app"))] #[cfg(any(feature = "_nrf52", feature = "_nrf5340-app"))]
unsafe { unsafe {
let value = if cfg!(feature = "nfc-pins-as-gpio") { 0 } else { !0 }; let value = if cfg!(feature = "nfc-pins-as-gpio") { 0 } else { 1 };
let res = uicr_write(consts::UICR_NFCPINS, value); let res = uicr_write_masked(consts::UICR_NFCPINS, value, 1);
needs_reset |= res == WriteResult::Written; needs_reset |= res == WriteResult::Written;
if res == WriteResult::Failed { if res == WriteResult::Failed {
// with nfc-pins-as-gpio, this can never fail because we're writing all zero bits. // with nfc-pins-as-gpio, this can never fail because we're writing all zero bits.