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//! # Control the LP core
//!
//! ## Overview
//! The `LP_CORE` driver provides an interface for controlling and managing the
//! low power core of `ESP` chips, allowing efficient low power operation and
//! wakeup from sleep based on configurable sources. The low power core is
//! responsible for executing low power tasks while the high power core is in
//! sleep mode.
//!
//! The `LpCore` struct provides methods to stop and run the low power core.
//!
//! The `stop` method stops the low power core, putting it into a sleep state.
//!
//! The `run` method starts the low power core and specifies the wakeup source.
//!
//! ## Example
//! ```no_run
//! const CODE: &[u8] = &[
//!     0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00,
//!     0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00,
//!     0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13,
//!     0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00,
//!     0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00,
//!     0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00,
//!     0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13,
//!     0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00,
//!     0x13, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x17, 0x05, 0x00, 0x00, 0x13, 0x05, 0x05,
//!     0x04, 0x85, 0x45, 0x23, 0x00, 0xb5, 0x00, 0xb7, 0x26, 0x0b, 0x60, 0xa1, 0x06, 0x37, 0x26,
//!     0x0b, 0x60, 0x11, 0x06, 0x09, 0x47, 0x18, 0xc2, 0xb7, 0x47, 0x0f, 0x00, 0x93, 0x87, 0x07,
//!     0x24, 0xfd, 0x17, 0xfd, 0xff, 0x85, 0x05, 0x23, 0x00, 0xb5, 0x00, 0x98, 0xc2, 0xb7, 0x47,
//!     0x0f, 0x00, 0x93, 0x87, 0x07, 0x24, 0xfd, 0x17, 0xfd, 0xff, 0xf9, 0xbf, 0x00, 0x00, 0x00,
//!     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
//! ];
//!
//! // configure GPIO 1 as LP output pin
//! let mut lp_pin = io.pins.gpio1.into_low_power();
//! lp_pin.output_enable(true);
//!
//! let mut lp_core = esp_hal::lp_core::LpCore::new(peripherals.LP_CORE);
//! lp_core.stop();
//! println!("lp core stopped");
//!
//! // copy code to LP ram
//! let lp_ram = 0x5000_0000 as *mut u8;
//! unsafe {
//!     core::ptr::copy_nonoverlapping(CODE as *const _ as *const u8, lp_ram, CODE.len());
//! }
//! println!("copied code (len {})", CODE.len());
//!
//! // start LP core
//! lp_core.run(lp_core::LpCoreWakeupSource::HpCpu);
//! println!("lpcore run");
//!
//! let data = (0x500000c0) as *mut u32;
//! loop {
//!     print!("Current {:x}           \u{000d}", unsafe {
//!         data.read_volatile()
//!     });
//! }
//! ```

use esp32c6 as pac;

use crate::peripheral::{Peripheral, PeripheralRef};

#[derive(Debug, Clone, Copy)]
pub enum LpCoreWakeupSource {
    HpCpu,
}

/// Clock sources for the LP core
#[derive(Debug, Clone, Copy)]
pub enum LpCoreClockSource {
    /// 17.5 MHz clock
    ///
    /// Might not be very accurate
    RcFastClk,
    /// 20 MHz clock
    XtalD2Clk,
}

pub struct LpCore<'d> {
    _lp_core: PeripheralRef<'d, crate::soc::peripherals::LP_CORE>,
}

impl<'d> LpCore<'d> {
    /// Create a new instance using [LpCoreClockSource::RcFastClk]
    pub fn new(lp_core: impl Peripheral<P = crate::soc::peripherals::LP_CORE> + 'd) -> Self {
        LpCore::new_with_clock(lp_core, LpCoreClockSource::RcFastClk)
    }

    /// Create a new instance using the given clock
    pub fn new_with_clock(
        lp_core: impl Peripheral<P = crate::soc::peripherals::LP_CORE> + 'd,
        clk_src: LpCoreClockSource,
    ) -> Self {
        crate::into_ref!(lp_core);

        match clk_src {
            LpCoreClockSource::RcFastClk => unsafe {
                (*crate::soc::peripherals::LP_CLKRST::PTR)
                    .lp_clk_conf()
                    .modify(|_, w| w.fast_clk_sel().clear_bit())
            },
            LpCoreClockSource::XtalD2Clk => unsafe {
                (*crate::soc::peripherals::LP_CLKRST::PTR)
                    .lp_clk_conf()
                    .modify(|_, w| w.fast_clk_sel().set_bit())
            },
        }

        let mut this = Self { _lp_core: lp_core };
        this.stop();

        // clear all of LP_RAM - this makes sure .bss is cleared without relying
        let lp_ram =
            unsafe { core::slice::from_raw_parts_mut(0x5000_0000 as *mut u32, 16 * 1024 / 4) };
        lp_ram.fill(0u32);

        this
    }

    /// Stop the LP core
    pub fn stop(&mut self) {
        ulp_lp_core_stop();
    }

    /// Start the LP core
    pub fn run(&mut self, wakeup_src: LpCoreWakeupSource) {
        ulp_lp_core_run(wakeup_src);
    }
}

fn ulp_lp_core_stop() {
    let pmu = unsafe { &*pac::PMU::PTR };
    pmu.lp_cpu_pwr1()
        .modify(|_, w| unsafe { w.lp_cpu_wakeup_en().bits(0) });
    pmu.lp_cpu_pwr1()
        .modify(|_, w| w.lp_cpu_sleep_req().set_bit());
}

fn ulp_lp_core_run(wakeup_src: LpCoreWakeupSource) {
    let lp_aon = unsafe { &*pac::LP_AON::PTR };
    let pmu = unsafe { &*pac::PMU::PTR };
    let lp_peri = unsafe { &*pac::LP_PERI::PTR };

    // Enable LP-Core
    lp_aon.lpcore().modify(|_, w| w.disable().clear_bit());

    // Allow LP core to access LP memory during sleep
    lp_aon
        .lpbus()
        .modify(|_, w| w.fast_mem_mux_sel().clear_bit());
    lp_aon
        .lpbus()
        .modify(|_, w| w.fast_mem_mux_sel_update().set_bit());

    // Enable stall at sleep request
    pmu.lp_cpu_pwr0()
        .modify(|_, w| w.lp_cpu_slp_stall_en().set_bit());

    // Enable reset after wake-up
    pmu.lp_cpu_pwr0()
        .modify(|_, w| w.lp_cpu_slp_reset_en().set_bit());

    // Set wake-up sources
    let src = match wakeup_src {
        LpCoreWakeupSource::HpCpu => 0x01,
    };
    pmu.lp_cpu_pwr1()
        .modify(|_, w| w.lp_cpu_wakeup_en().variant(src));

    // Enable JTAG debugging
    lp_peri
        .cpu()
        .modify(|_, w| w.lpcore_dbgm_unavaliable().clear_bit());

    // wake up
    match wakeup_src {
        LpCoreWakeupSource::HpCpu => {
            pmu.hp_lp_cpu_comm().write(|w| w.hp_trigger_lp().set_bit());
        }
    }
}