//! STM32F722 Pll216 clock-source assembly.

use super::peripherals::{DwtMicrosecondClock, select_pll216_profile};
use kaptan_err_reportable::KaptanError;
use stm32f7::stm32f722;

/// Core frequency in whole megahertz after selecting the PLL216 board profile.
const CORE_CLOCK_MHZ: u32 = 216;

/// A failure while establishing the board's clock tree or monotonic clock.
#[derive(Clone, Copy, Debug, Eq, PartialEq, KaptanError)]
pub(crate) enum ClockInitializationError {
    #[kaptan_error(id = 11801)]
    Profile,
    #[kaptan_error(id = 11802)]
    Monotonic,
}

/// Selects the F722 Pll216 profile and starts its monotonic microsecond clock.
pub(crate) fn initialize(
    core: &mut cortex_m::Peripherals,
    device: &stm32f722::Peripherals,
) -> Result<DwtMicrosecondClock, ClockInitializationError> {
    select_pll216_profile(&device.RCC, &device.PWR, &device.FLASH)
        .map_err(|_| ClockInitializationError::Profile)?;
    core.SCB.disable_dcache(&mut core.CPUID);
    DwtMicrosecondClock::start::<CORE_CLOCK_MHZ>(&mut core.DCB, &mut core.DWT)
        .map_err(|_| ClockInitializationError::Monotonic)
}