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// SPDX-FileCopyrightText: 2020 Sean Cross <sean@xobs.io>

// SPDX-License-Identifier: Apache-2.0

use riscv::register::{satp, sie, sstatus};

pub mod exception;

pub mod irq;

pub mod mem;

pub mod panic;

pub mod process;

pub mod syscall;

#[cfg(any(feature = "precursor", feature = "renode"))]

use utralib::generated::*;

#[cfg(any(feature = "bao1x"))]

use xous_kernel::PID;

#[cfg(any(feature = "precursor", feature = "renode"))]

use xous_kernel::{MemoryFlags, MemoryType, PID};

#[cfg(any(feature = "precursor", feature = "renode"))]

use crate::mem::MemoryManager;

#[cfg(any(feature = "precursor", feature = "renode"))]

pub const WFI_KERNEL: Wfi = Wfi {

// the manually chosen virtual address has to be in the top 4MiB as it is the only page shared among all

// processes

base: 0xffcd_0000 as *mut usize, /* see https://github.com/betrusted-io/xous-core/blob/master/docs/memory.md */

};

#[cfg(any(feature = "precursor", feature = "renode"))]

pub struct Wfi {

pub base: *mut usize,

}

pub fn current_pid() -> PID { PID::new(satp::read().asid() as _).unwrap() }

pub fn init() {

#[cfg(any(feature = "precursor", feature = "renode"))]

MemoryManager::with_mut(|memory_manager| {

memory_manager

.map_range(

utra::wfi::HW_WFI_BASE as *mut u8,

((WFI_KERNEL.base as u32) & !4095) as *mut u8,

4096,

PID::new(1).unwrap(),

MemoryFlags::R | MemoryFlags::W,

MemoryType::Default,

)

.expect("unable to map WFI")

});

#[cfg(any(feature = "precursor", feature = "renode"))]

let mut wfi_kernel_csr = CSR::new(WFI_KERNEL.base as *mut u32);

#[cfg(any(feature = "precursor", feature = "renode"))]

wfi_kernel_csr.wfo(utra::wfi::IGNORE_LOCKED_IGNORE_LOCKED, 1);

unsafe {

sie::set_ssoft();

sie::set_sext();

}

}

/// Put the core to sleep until an interrupt hits. Returns \\`true\\`

/// to indicate the kernel should not exit.

pub fn idle() -> bool {

// Issue \\`wfi\\`. This will return as soon as an external interrupt

// is available.

#[cfg(any(feature = "bao1x", feature = "renode"))]

// "traditional" path for stopping a clock

unsafe {

riscv::asm::wfi()

};

#[cfg(any(feature = "precursor"))]

{

let mut wfi_kernel_csr = CSR::new(WFI_KERNEL.base as *mut u32);

// this invokes Precusor-SoC specific path to gate clocks:

// 1. ignore_locked prevents the chip from going into reset if the PLL goes unlocked

wfi_kernel_csr.wfo(utra::wfi::IGNORE_LOCKED_IGNORE_LOCKED, 1);

// 2. wfi gates all the clocks (stops them) until a SoC-defined interrupt comes in

wfi_kernel_csr.wfo(utra::wfi::WFI_WFI, 1);

}

// Enable interrupts temporarily in Supervisor mode, allowing them

// to drain. Aside from this brief instance, interrupts are

// disabled when running in Supervisor mode.

//

// These interrupts are handled by userspace, so code execution will

// immediately jump to the interrupt handler and return here after

// all interrupts have been handled.

unsafe {

sstatus::set_sie();

sstatus::clear_sie();

};

true

}