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fix RTC setting bug - don't reset if it's already set

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the backup RAM region is being used as a way to check if the
system is coming out of a cold power-on. Deep sleep is indistinguishable
from a power-on from the hashing perspective. Check if the RTC is
*enabled* and if not, enable it and reset the time; don't always
reset it if the backup ram is scrambled.
This commit is contained in:
bunnie 2025-12-22 02:06:22 +08:00
parent a5303a707f
commit 00fe25b28c
1 changed files with 25 additions and 13 deletions
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38
bao1x-boot/boot1/src/platform/bao1x/bao1x.rs
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@ -110,21 +110,27 @@ pub fn setup_backup_region() -> u32 {
acc += i as u32;
}
// enable the RTC if it isn't already - on a cold boot, it would be off
let mut ao_sysctrl = CSR::new(utralib::HW_AO_SYSCTRL_BASE as *mut u32);
// set effective tick to 1/1024th of a second
// this causes the RTC to roll over every 48 days - the code before had some deniability about
// RTC offset because it would roll over every 168 years, but I think once every 48 days is within
// a reasonable window of deniability (previously it was a random number from 0-6 months) and
// also the system has to be powered on at least once every rollover window to capture the rollover.
// The device won't last 48 days on RTC battery alone - and every time a QR code is scanned you
// update the RTC offset. So I think this is a reasonable window to just leave "as so". The
// initial value is set to within minutes of a roll-over, so that an error in rollover handling
// would be detected quickly.
ao_sysctrl.wo(utra::ao_sysctrl::CR_CLK1HZFD, 15);
let mut rtc = CSR::new(bao1x_hal::rtc::HW_RTC_BASE as *mut u32);
rtc.wo(bao1x_hal::rtc::LR, 0xFFFE_2000); // set base to "roll over" in 2 minutes - forces an edge case in testing
rtc.wfo(bao1x_hal::rtc::CR_EN, 1);
// enable the RTC if it isn't already - on a cold boot, it would be off
if rtc.rf(bao1x_hal::rtc::CR_EN) != 1 {
// set effective tick to 1/1024th of a second
// this causes the RTC to roll over every 48 days - the code before had some deniability about
// RTC offset because it would roll over every 168 years, but I think once every 48 days is within
// a reasonable window of deniability (previously it was a random number from 0-6 months) and
// also the system has to be powered on at least once every rollover window to capture the
// rollover. The device won't last 48 days on RTC battery alone - and every time a QR
// code is scanned you update the RTC offset. So I think this is a reasonable window
// to just leave "as so". The initial value is set to within minutes of a roll-over,
// so that an error in rollover handling would be detected quickly.
ao_sysctrl.wo(utra::ao_sysctrl::CR_CLK1HZFD, 15);
rtc.wo(bao1x_hal::rtc::LR, 0xFFFE_2000); // set base to "roll over" in 2 minutes - forces an edge case in testing
rtc.wfo(bao1x_hal::rtc::CR_EN, 1);
let mut backup_flags = bu_mgr.get_flags();
backup_flags.set_rtc_synchronized(false);
bu_mgr.set_flags(backup_flags);
}
// soft-reset the system
let mut rcurst = CSR::new(utra::sysctrl::HW_SYSCTRL_BASE as *mut u32);
@ -162,6 +168,12 @@ pub fn early_init(mut board_type: bao1x_api::BoardTypeCoding) -> (bao1x_api::Boa
if setup_backup_region() == 0 {
crate::println!("backup region is clean!");
}
/* // debug RTC setting - remove once confident
let rtc = CSR::new(bao1x_hal::rtc::HW_RTC_BASE as *mut u32);
for i in 0..8 {
crate::println_d!("rtc {}: {:x}", i, unsafe { rtc.base().add(i).read_volatile() });
}
*/
// setup board-specific I/Os - early boot set. These are items that have to be
// done in a time-sensitive fashion.