84 lines
3.7 KiB
Rust
84 lines
3.7 KiB
Rust
|
use crate::syscalls;
|
||
|
|
use xous_riscv::register::{mstatus, vmim};
|
||
|
|
|
||
|
|
// Shamelessly taken from
|
||
|
|
// https://stackoverflow.com/questions/36258417/using-a-macro-to-initialize-a-big-array-of-non-copy-elements
|
||
|
|
// Allows us to fill an array with a predefined value.
|
||
|
|
macro_rules! filled_array {
|
||
|
|
(@accum (0, $($_es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@as_expr [$($body)*])};
|
||
|
|
(@accum (1, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (0, $($es),*) -> ($($body)* $($es,)*))};
|
||
|
|
(@accum (2, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (0, $($es),*) -> ($($body)* $($es,)* $($es,)*))};
|
||
|
|
(@accum (3, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (2, $($es),*) -> ($($body)* $($es,)*))};
|
||
|
|
(@accum (4, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (2, $($es,)* $($es),*) -> ($($body)*))};
|
||
|
|
(@accum (5, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (4, $($es),*) -> ($($body)* $($es,)*))};
|
||
|
|
(@accum (6, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (4, $($es),*) -> ($($body)* $($es,)* $($es,)*))};
|
||
|
|
(@accum (7, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (4, $($es),*) -> ($($body)* $($es,)* $($es,)* $($es,)*))};
|
||
|
|
(@accum (8, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (4, $($es,)* $($es),*) -> ($($body)*))};
|
||
|
|
(@accum (16, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (8, $($es,)* $($es),*) -> ($($body)*))};
|
||
|
|
(@accum (32, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (16, $($es,)* $($es),*) -> ($($body)*))};
|
||
|
|
(@accum (64, $($es:expr),*) -> ($($body:tt)*))
|
||
|
|
=> {filled_array!(@accum (32, $($es,)* $($es),*) -> ($($body)*))};
|
||
|
|
|
||
|
|
(@as_expr $e:expr) => {$e};
|
||
|
|
|
||
|
|
[$e:expr; $n:tt] => { filled_array!(@accum ($n, $e) -> ()) };
|
||
|
|
}
|
||
|
|
|
||
|
|
static mut IRQ_HANDLERS: [Option<fn(usize)>; 32] = filled_array![None; 32];
|
||
|
|
|
||
|
|
pub fn handle(irqs_pending: usize) {
|
||
|
|
// Unsafe is required here because we're accessing a static
|
||
|
|
// mutable value, and it could be modified from various threads.
|
||
|
|
// However, this is fine because this is run from an IRQ context
|
||
|
|
// with interrupts disabled.
|
||
|
|
// NOTE: This will become an issue when running with multiple cores,
|
||
|
|
// so this should be protected by a mutex.
|
||
|
|
unsafe {
|
||
|
|
for irq_no in 0..IRQ_HANDLERS.len() {
|
||
|
|
if irqs_pending & (1 << irq_no) != 0 {
|
||
|
|
if let Some(f) = IRQ_HANDLERS[irq_no] {
|
||
|
|
// Call the IRQ handler
|
||
|
|
f(irq_no);
|
||
|
|
} else {
|
||
|
|
// If there is no handler, mask this interrupt
|
||
|
|
// to prevent an IRQ storm. This is considered
|
||
|
|
// an error.
|
||
|
|
vmim::write(vmim::read() | (1 << irq_no));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
pub fn sys_interrupt_claim(irq: usize, f: fn(usize)) -> Result<(), syscalls::XousError> {
|
||
|
|
// Unsafe is required since we're accessing a static mut array.
|
||
|
|
// However, we disable interrupts to prevent contention on this array.
|
||
|
|
unsafe {
|
||
|
|
mstatus::clear_mie();
|
||
|
|
let result = if irq > IRQ_HANDLERS.len() {
|
||
|
|
Err(syscalls::XousError::InterruptNotFound)
|
||
|
|
} else if IRQ_HANDLERS[irq].is_some() {
|
||
|
|
Err(syscalls::XousError::InterruptInUse)
|
||
|
|
} else {
|
||
|
|
IRQ_HANDLERS[irq] = Some(f);
|
||
|
|
// Note that the vexriscv "IRQ Mask" register is inverse-logic --
|
||
|
|
// that is, setting a bit in the "mask" register unmasks (i.e. enables) it.
|
||
|
|
vmim::write(vmim::read() | (1 << irq));
|
||
|
|
Ok(())
|
||
|
|
};
|
||
|
|
mstatus::set_mie();
|
||
|
|
result
|
||
|
|
}
|
||
|
|
}
|