mod.rs

//! Clocks (CLOCKS)
//!
//!
//!
//! ## Usage simple
//! ```no_run
//! use rp2040_hal::{clocks::init_clocks_and_plls, watchdog::Watchdog, pac};
//!
//! let mut peripherals = pac::Peripherals::take().unwrap();
//! let mut watchdog = Watchdog::new(peripherals.WATCHDOG);
//! const XOSC_CRYSTAL_FREQ: u32 = 12_000_000; // Typically found in BSP crates
//! let mut clocks = init_clocks_and_plls(XOSC_CRYSTAL_FREQ, peripherals.XOSC, peripherals.CLOCKS, peripherals.PLL_SYS, peripherals.PLL_USB, &mut peripherals.RESETS, &mut watchdog).ok().unwrap();
//! ```
//!
//! ## Usage extended
//! ```no_run
//! use fugit::RateExtU32;
//! use rp2040_hal::{clocks::{Clock, ClocksManager, ClockSource, InitError}, gpio::Pins, pac, pll::{common_configs::{PLL_SYS_125MHZ, PLL_USB_48MHZ}, setup_pll_blocking}, Sio, watchdog::Watchdog, xosc::setup_xosc_blocking};
//!
//! # fn func() -> Result<(), InitError> {
//! let mut peripherals = pac::Peripherals::take().unwrap();
//! let mut watchdog = Watchdog::new(peripherals.WATCHDOG);
//! const XOSC_CRYSTAL_FREQ: u32 = 12_000_000; // Typically found in BSP crates
//!
//! // Enable the xosc
//! let xosc = setup_xosc_blocking(peripherals.XOSC, XOSC_CRYSTAL_FREQ.Hz()).map_err(InitError::XoscErr)?;
//!
//! // Start tick in watchdog
//! watchdog.enable_tick_generation((XOSC_CRYSTAL_FREQ / 1_000_000) as u16);
//!
//! let mut clocks = ClocksManager::new(peripherals.CLOCKS);
//!
//! // Configure PLLs
//! //                   REF     FBDIV VCO            POSTDIV
//! // PLL SYS: 12 / 1 = 12MHz * 125 = 1500MHZ / 6 / 2 = 125MHz
//! // PLL USB: 12 / 1 = 12MHz * 40  = 480 MHz / 5 / 2 =  48MHz
//! let pll_sys = setup_pll_blocking(peripherals.PLL_SYS, xosc.operating_frequency().into(), PLL_SYS_125MHZ, &mut clocks, &mut peripherals.RESETS).map_err(InitError::PllError)?;
//! let pll_usb = setup_pll_blocking(peripherals.PLL_USB, xosc.operating_frequency().into(), PLL_USB_48MHZ, &mut clocks, &mut peripherals.RESETS).map_err(InitError::PllError)?;
//!
//! // Configure clocks
//! // CLK_REF = XOSC (12MHz) / 1 = 12MHz
//! clocks.reference_clock.configure_clock(&xosc, xosc.get_freq()).map_err(InitError::ClockError)?;
//!
//! // CLK SYS = PLL SYS (125MHz) / 1 = 125MHz
//! clocks.system_clock.configure_clock(&pll_sys, pll_sys.get_freq()).map_err(InitError::ClockError)?;
//!
//! // CLK USB = PLL USB (48MHz) / 1 = 48MHz
//! clocks.usb_clock.configure_clock(&pll_usb, pll_usb.get_freq()).map_err(InitError::ClockError)?;
//!
//! // CLK ADC = PLL USB (48MHZ) / 1 = 48MHz
//! clocks.adc_clock.configure_clock(&pll_usb, pll_usb.get_freq()).map_err(InitError::ClockError)?;
//!
//! // CLK RTC = PLL USB (48MHz) / 1024 = 46875Hz
//! clocks.rtc_clock.configure_clock(&pll_usb, 46875u32.Hz()).map_err(InitError::ClockError)?;
//!
//! // CLK PERI = clk_sys. Used as reference clock for Peripherals. No dividers so just select and enable
//! // Normally choose clk_sys or clk_usb
//! clocks.peripheral_clock.configure_clock(&clocks.system_clock, clocks.system_clock.freq()).map_err(InitError::ClockError)?;
//! # Ok(())
//! # }
//! ```
//!
//! See [Chapter 2 Section 15](https://datasheets.raspberrypi.org/rp2040/rp2040_datasheet.pdf) for more details
use core::{convert::Infallible, marker::PhantomData};
use fugit::{HertzU32, RateExtU32};

use crate::{
    pac::{self, CLOCKS, PLL_SYS, PLL_USB, RESETS, XOSC},
    pll::{
        common_configs::{PLL_SYS_125MHZ, PLL_USB_48MHZ},
        setup_pll_blocking, Error as PllError, Locked, PhaseLockedLoop,
    },
    typelevel::Sealed,
    watchdog::Watchdog,
    xosc::{setup_xosc_blocking, CrystalOscillator, Error as XoscError, Stable},
};

#[macro_use]
mod macros;
mod clock_sources;

use clock_sources::PllSys;

use self::clock_sources::{GPin0, GPin1, PllUsb, Rosc, Xosc};

#[derive(Copy, Clone)]
/// Provides refs to the CLOCKS block.
struct ShareableClocks {
    _internal: (),
}

impl ShareableClocks {
    fn new(_clocks: &mut CLOCKS) -> Self {
        ShareableClocks { _internal: () }
    }

    unsafe fn get(&self) -> &pac::clocks::RegisterBlock {
        &*CLOCKS::ptr()
    }
}

/// Something when wrong setting up the clock
#[non_exhaustive]
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub enum ClockError {
    /// The frequency desired is higher than the source frequency
    CantIncreaseFreq,
    /// The desired frequency is to high (would overflow an u32)
    FrequencyTooHigh,
    /// The desired frequency is too low (divider can't reach the desired value)
    FrequencyTooLow,
}

/// For clocks
pub trait Clock: Sealed + Sized {
    /// Enum with valid source clocks register values for `Clock`
    type Variant;

    /// Get operating frequency
    fn freq(&self) -> HertzU32;

    /// Configure this clock based on a clock source and desired frequency
    fn configure_clock<S: ValidSrc<Self>>(
        &mut self,
        src: &S,
        freq: HertzU32,
    ) -> Result<(), ClockError>;
}

/// For clocks with a divider
trait ClockDivision {
    /// Set integer divider value.
    fn set_div(&mut self, div: u32);
    /// Get integer diveder value.
    fn get_div(&self) -> u32;
}

/// Clock with glitchless source
trait GlitchlessClock {
    /// Self type to hand to ChangingClockToken
    type Clock: Clock;

    /// Await switching clock sources without glitches. Needs a token that is returned when setting
    fn await_select(
        &self,
        clock_token: &ChangingClockToken<Self::Clock>,
    ) -> nb::Result<(), Infallible>;
}

/// Token which can be used to await the glitchless switch
pub struct ChangingClockToken<G: Clock> {
    clock_nr: u8,
    clock: PhantomData<G>,
}

/// For clocks that can be disabled
pub trait StoppableClock: Sealed {
    /// Enables the clock.
    fn enable(&mut self);

    /// Disables the clock.
    fn disable(&mut self);

    /// Kills the clock.
    fn kill(&mut self);
}

/// Trait for things that can be used as clock source
pub trait ClockSource: Sealed {
    /// Get the operating frequency for this source
    ///
    /// Used to determine the divisor
    fn get_freq(&self) -> HertzU32;
}

/// Trait to contrain which ClockSource is valid for which Clock
pub trait ValidSrc<C: Clock>: Sealed + ClockSource {
    /// Is this a ClockSource for src or aux?
    fn is_aux(&self) -> bool;
    /// Get register value for this ClockSource
    fn variant(&self) -> C::Variant;
}

clocks! {
    /// GPIO Output 0 Clock
    struct GpioOutput0Clock {
        init_freq: 0,
        reg: clk_gpout0,
        auxsrc: {PllSys:CLKSRC_PLL_SYS, GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1, PllUsb:CLKSRC_PLL_USB, Rosc: ROSC_CLKSRC, Xosc: XOSC_CLKSRC, SystemClock: CLK_SYS, UsbClock: CLK_USB, AdcClock: CLK_ADC, RtcClock: CLK_RTC, ReferenceClock:CLK_REF}
    }
    /// GPIO Output 1 Clock
    struct GpioOutput1Clock {
        init_freq: 0,
        reg: clk_gpout1,
        auxsrc: {PllSys:CLKSRC_PLL_SYS, GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1, PllUsb:CLKSRC_PLL_USB, Rosc: ROSC_CLKSRC, Xosc: XOSC_CLKSRC, SystemClock: CLK_SYS, UsbClock: CLK_USB, AdcClock: CLK_ADC, RtcClock: CLK_RTC, ReferenceClock:CLK_REF}
    }
    /// GPIO Output 2 Clock
    struct GpioOutput2Clock {
        init_freq: 0,
        reg: clk_gpout2,
        auxsrc: {PllSys:CLKSRC_PLL_SYS, GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1, PllUsb:CLKSRC_PLL_USB, Rosc: ROSC_CLKSRC_PH, Xosc: XOSC_CLKSRC, SystemClock: CLK_SYS, UsbClock: CLK_USB, AdcClock: CLK_ADC, RtcClock: CLK_RTC, ReferenceClock:CLK_REF}
    }
    /// GPIO Output 3 Clock
    struct GpioOutput3Clock {
        init_freq: 0,
        reg: clk_gpout3,
        auxsrc: {PllSys:CLKSRC_PLL_SYS, GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1, PllUsb:CLKSRC_PLL_USB, Rosc: ROSC_CLKSRC_PH, Xosc: XOSC_CLKSRC, SystemClock: CLK_SYS, UsbClock: CLK_USB, AdcClock: CLK_ADC, RtcClock: CLK_RTC, ReferenceClock:CLK_REF}
    }
    /// Reference Clock
    struct ReferenceClock {
        init_freq: 12_000_000,  // Starts from ROSC which actually varies with input voltage etc, but 12 MHz seems to be a good value
        reg: clk_ref,
        src: {Rosc: ROSC_CLKSRC_PH, Xosc:XOSC_CLKSRC},
        auxsrc: {PllUsb:CLKSRC_PLL_USB, GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1}
    }
    /// System Clock
    struct SystemClock {
        init_freq: 12_000_000,  // ref_clk is 12 MHz
        reg: clk_sys,
        src: {ReferenceClock: CLK_REF},
        auxsrc: {PllSys: CLKSRC_PLL_SYS, PllUsb:CLKSRC_PLL_USB, Rosc: ROSC_CLKSRC, Xosc: XOSC_CLKSRC,GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1}
    }
    /// Peripheral Clock
    struct PeripheralClock {
        init_freq: 12_000_000,  // sys_clk is 12 MHz
        reg: clk_peri,
        auxsrc: {SystemClock: CLK_SYS, PllSys: CLKSRC_PLL_SYS, PllUsb:CLKSRC_PLL_USB, Rosc: ROSC_CLKSRC_PH, Xosc: XOSC_CLKSRC,GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1 },
        div: false
    }
    /// USB Clock
    struct UsbClock {
        init_freq: 0,
        reg: clk_usb,
        auxsrc: {PllUsb:CLKSRC_PLL_USB,PllSys: CLKSRC_PLL_SYS,  Rosc: ROSC_CLKSRC_PH, Xosc: XOSC_CLKSRC,GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1}
    }
    /// Adc Clock
    struct AdcClock {
        init_freq: 0,
        reg: clk_adc,
        auxsrc: {PllUsb:CLKSRC_PLL_USB,PllSys: CLKSRC_PLL_SYS,  Rosc: ROSC_CLKSRC_PH, Xosc: XOSC_CLKSRC,GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1}
    }
    /// RTC Clock
    struct RtcClock {
        init_freq: 0,
        reg: clk_rtc,
        auxsrc: {PllUsb:CLKSRC_PLL_USB,PllSys: CLKSRC_PLL_SYS,  Rosc: ROSC_CLKSRC_PH, Xosc: XOSC_CLKSRC,GPin0:CLKSRC_GPIN0, GPin1:CLKSRC_GPIN1}
    }
}

impl SystemClock {
    fn get_default_clock_source(&self) -> pac::clocks::clk_sys_ctrl::SRC_A {
        pac::clocks::clk_sys_ctrl::SRC_A::CLK_REF
    }

    fn get_aux_source(&self) -> pac::clocks::clk_sys_ctrl::SRC_A {
        pac::clocks::clk_sys_ctrl::SRC_A::CLKSRC_CLK_SYS_AUX
    }
}

impl ReferenceClock {
    fn get_default_clock_source(&self) -> pac::clocks::clk_ref_ctrl::SRC_A {
        pac::clocks::clk_ref_ctrl::SRC_A::ROSC_CLKSRC_PH
    }

    fn get_aux_source(&self) -> pac::clocks::clk_ref_ctrl::SRC_A {
        pac::clocks::clk_ref_ctrl::SRC_A::CLKSRC_CLK_REF_AUX
    }
}

impl ClocksManager {
    /// Initialize the clocks to a sane default
    pub fn init_default(
        &mut self,
        xosc: &CrystalOscillator<Stable>,
        pll_sys: &PhaseLockedLoop<Locked, PLL_SYS>,
        pll_usb: &PhaseLockedLoop<Locked, PLL_USB>,
    ) -> Result<(), ClockError> {
        // Configure clocks
        // CLK_REF = XOSC (12MHz) / 1 = 12MHz
        self.reference_clock
            .configure_clock(xosc, xosc.get_freq())?;

        // CLK SYS = PLL SYS (125MHz) / 1 = 125MHz
        self.system_clock
            .configure_clock(pll_sys, pll_sys.get_freq())?;

        // CLK USB = PLL USB (48MHz) / 1 = 48MHz
        self.usb_clock
            .configure_clock(pll_usb, pll_usb.get_freq())?;

        // CLK ADC = PLL USB (48MHZ) / 1 = 48MHz
        self.adc_clock
            .configure_clock(pll_usb, pll_usb.get_freq())?;

        // CLK RTC = PLL USB (48MHz) / 1024 = 46875Hz
        self.rtc_clock.configure_clock(pll_usb, 46875u32.Hz())?;

        // CLK PERI = clk_sys. Used as reference clock for Peripherals. No dividers so just select and enable
        // Normally choose clk_sys or clk_usb
        self.peripheral_clock
            .configure_clock(&self.system_clock, self.system_clock.freq())
    }

    /// Releases the CLOCKS block
    pub fn free(self) -> CLOCKS {
        self.clocks
    }
}

/// Possible init errors
pub enum InitError {
    /// Something went wrong setting up the Xosc
    XoscErr(XoscError),
    /// Something went wrong setting up the Pll
    PllError(PllError),
    /// Something went wrong setting up the Clocks
    ClockError(ClockError),
}

/// Initialize the clocks and plls according to the reference implementation
pub fn init_clocks_and_plls(
    xosc_crystal_freq: u32,
    xosc_dev: XOSC,
    clocks_dev: CLOCKS,
    pll_sys_dev: PLL_SYS,
    pll_usb_dev: PLL_USB,
    resets: &mut RESETS,
    watchdog: &mut Watchdog,
) -> Result<ClocksManager, InitError> {
    let xosc = setup_xosc_blocking(xosc_dev, xosc_crystal_freq.Hz()).map_err(InitError::XoscErr)?;

    // Configure watchdog tick generation to tick over every microsecond
    watchdog.enable_tick_generation((xosc_crystal_freq / 1_000_000) as u16);

    let mut clocks = ClocksManager::new(clocks_dev);

    let pll_sys = setup_pll_blocking(
        pll_sys_dev,
        xosc.operating_frequency(),
        PLL_SYS_125MHZ,
        &mut clocks,
        resets,
    )
    .map_err(InitError::PllError)?;
    let pll_usb = setup_pll_blocking(
        pll_usb_dev,
        xosc.operating_frequency(),
        PLL_USB_48MHZ,
        &mut clocks,
        resets,
    )
    .map_err(InitError::PllError)?;

    clocks
        .init_default(&xosc, &pll_sys, &pll_usb)
        .map_err(InitError::ClockError)?;
    Ok(clocks)
}

// Calculates (numerator<<8)/denominator, avoiding 64bit division
// Returns None if the result would not fit in 32 bit.
fn fractional_div(numerator: u32, denominator: u32) -> Option<u32> {
    if denominator.eq(&numerator) {
        return Some(1 << 8);
    }

    let div_int = numerator / denominator;
    if div_int >= 1 << 24 {
        return None;
    }

    let div_rem = numerator - (div_int * denominator);

    let div_frac = if div_rem < 1 << 24 {
        // div_rem is small enough to shift it by 8 bits without overflow
        (div_rem << 8) / denominator
    } else {
        // div_rem is too large. Shift denominator right, instead.
        // As 1<<24 < div_rem < denominator, relative error caused by the
        // lost lower 8 bits of denominator is smaller than 2^-16
        (div_rem) / (denominator >> 8)
    };

    Some((div_int << 8) + div_frac)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_fractional_div() {
        // easy values
        assert_eq!(fractional_div(1, 1), Some(1 << 8));

        // typical values
        assert_eq!(fractional_div(125_000_000, 48_000_000), Some(666));
        assert_eq!(fractional_div(48_000_000, 46875), Some(1024 << 8));

        // resulting frequencies
        assert_eq!(
            fractional_div(
                125_000_000,
                fractional_div(125_000_000, 48_000_000).unwrap()
            ),
            Some(48_048_048)
        );
        assert_eq!(
            fractional_div(48_000_000, fractional_div(48_000_000, 46875).unwrap()),
            Some(46875)
        );

        // not allowed in src/clocks/mod.rs, but should still deliver correct results
        assert_eq!(fractional_div(1, 2), Some(128));
        assert_eq!(fractional_div(1, 256), Some(1));
        assert_eq!(fractional_div(1, 257), Some(0));

        // borderline cases
        assert_eq!(fractional_div((1 << 24) - 1, 1), Some(((1 << 24) - 1) << 8));
        assert_eq!(fractional_div(1 << 24, 1), None);
        assert_eq!(fractional_div(1 << 24, 2), Some(1 << (23 + 8)));
        assert_eq!(fractional_div(1 << 24, (1 << 24) + 1), Some(1 << 8));
        assert_eq!(fractional_div(u32::MAX, u32::MAX), Some(1 << 8));
    }
}