rp-hal-boards/rp2040-hal/src/sio.rs

//! Single Cycle Input and Output (SIO)
//!
//! To be able to partition parts of the SIO block to other modules:
//!
//! ```rust
//! let mut peripherals = pac::Peripherals::take().unwrap();
//! let sio = Sio::new(peripherals.SIO);
//! ```
//!
//! And then for example
//!
//! ```rust
//! let pins = gpio:Pins::new(pac.IO_BANK0, pac.PADS_BANK0, sio.gpio_bank0, &mut pac.RESETS);
//! ```
use super::*;

/// Marker struct for ownership of SIO gpio bank0
pub struct SioGpioBank0 {
    _private: (),
}

/// Marker struct for ownership of SIO gpio qspi
pub struct SioGpioQspi {
    _private: (),
}

/// Marker struct for ownership of divide/modulo module
pub struct HwDivider {
    _private: (),
}

/// Result of divide/modulo operation
pub struct DivResult<T> {
    /// The remainder of divide/modulo operation
    pub remainder: T,
    /// The quotient of divide/modulo operation
    pub quotient: T,
}

/// Struct containing ownership markers for managing ownership of the SIO registers.
pub struct Sio {
    _sio: pac::SIO,
    /// GPIO Bank 0 registers
    pub gpio_bank0: SioGpioBank0,
    /// GPIO QSPI registers
    pub gpio_qspi: SioGpioQspi,
    /// 8-cycle hardware divide/modulo module
    pub hwdivider: HwDivider,
    // we can hand out other things here, for example:
    // interp0
    // interp1
}
impl Sio {
    /// Create `Sio` from the PAC.
    pub fn new(sio: pac::SIO) -> Self {
        Self {
            _sio: sio,

            gpio_bank0: SioGpioBank0 { _private: () },
            gpio_qspi: SioGpioQspi { _private: () },

            hwdivider: HwDivider { _private: () },
        }
    }
}

impl HwDivider {
    /// Perform hardware unsigned divide/modulo operation
    pub fn unsigned(&self, dividend: u32, divisor: u32) -> DivResult<u32> {
        let sio = unsafe { &(*pac::SIO::ptr()) };
        sio.div_sdividend.write(|w| unsafe { w.bits(dividend) });

        sio.div_sdivisor.write(|w| unsafe { w.bits(divisor) });

        cortex_m::asm::delay(8);

        // Note: quotient must be read last
        let remainder = sio.div_remainder.read().bits();
        let quotient = sio.div_quotient.read().bits();

        DivResult {
            remainder,
            quotient,
        }
    }

    /// Perform hardware signed divide/modulo operation
    pub fn signed(&self, dividend: i32, divisor: i32) -> DivResult<i32> {
        let sio = unsafe { &(*pac::SIO::ptr()) };
        sio.div_sdividend
            .write(|w| unsafe { w.bits(dividend as u32) });

        sio.div_sdivisor
            .write(|w| unsafe { w.bits(divisor as u32) });

        cortex_m::asm::delay(8);

        // Note: quotient must be read last
        let remainder = sio.div_remainder.read().bits() as i32;
        let quotient = sio.div_quotient.read().bits() as i32;

        DivResult {
            remainder,
            quotient,
        }
    }
}