Use const generics for spinlocks.

The fewer code-generating macros we have, the better!
This commit is contained in:
Jonathan 'theJPster' Pallant 2022-01-30 15:56:23 +00:00
parent c8c366c23d
commit 7e2f8d274c

View file

@ -207,16 +207,58 @@ impl HwDivider {
} }
} }
/// Trait for all the spinlock. See the documentation of e.g. [`Spinlock0`] for more information /// This type is just used to limit us to Spinlocks `0..=31`
pub trait Spinlock: typelevel::Sealed + Sized { pub trait SpinlockValid {}
/// Hardware based spinlock.
///
/// You can claim this lock by calling either [`claim`], [`try_claim`] or
/// [`claim_async`]. These spin-locks are hardware backed, so if you lock
/// `Spinlock<6>` any other part of your program using `Spinlock<6>` will
/// suddenly find it to be locked.
///
/// When the obtained spinlock goes out of scope, it is automatically unlocked.
///
/// **warning**: These spinlocks are not re-entrant, meaning that the following code will cause a deadlock:
///
/// ```no_run
/// use rp2040_hal::sio::Spinlock0;
/// let lock_1 = Spinlock0::claim();
/// let lock_2 = Spinlock0::claim(); // deadlock here
/// ```
///
/// Use `try_claim` if you are not the only piece of code using any given
/// spin-lock. Note also that the `critical-section` implementation uses
/// Spinlock 31.
///
/// [`claim`]: #method.claim
/// [`try_claim`]: #method.try_claim
/// [`claim_async`]: #method.claim_asyncs
pub struct Spinlock<const N: usize>(core::marker::PhantomData<()>)
where
Spinlock<N>: SpinlockValid;
impl<const N: usize> Spinlock<N>
where
Spinlock<N>: SpinlockValid,
{
/// Try to claim the spinlock. Will return `Some(Self)` if the lock is obtained, and `None` if the lock is /// Try to claim the spinlock. Will return `Some(Self)` if the lock is obtained, and `None` if the lock is
/// already in use somewhere else. /// already in use somewhere else.
fn try_claim() -> Option<Self>; pub fn try_claim() -> Option<Self> {
// Safety: We're only reading from this register
let sio = unsafe { &*pac::SIO::ptr() };
let lock = sio.spinlock[N].read().bits();
if lock > 0 {
Some(Self(core::marker::PhantomData))
} else {
None
}
}
/// Claim the spinlock, will block the current thread until the lock is available. /// Claim the spinlock, will block the current thread until the lock is available.
/// ///
/// Note that calling this multiple times in a row will cause a deadlock /// Note that calling this multiple times in a row will cause a deadlock
fn claim() -> Self { pub fn claim() -> Self {
loop { loop {
if let Some(result) = Self::try_claim() { if let Some(result) = Self::try_claim() {
break result; break result;
@ -225,98 +267,184 @@ pub trait Spinlock: typelevel::Sealed + Sized {
} }
/// Try to claim the spinlock. Will return `WouldBlock` until the spinlock is available. /// Try to claim the spinlock. Will return `WouldBlock` until the spinlock is available.
fn claim_async() -> nb::Result<Self, Infallible> { pub fn claim_async() -> nb::Result<Self, Infallible> {
Self::try_claim().ok_or(nb::Error::WouldBlock) Self::try_claim().ok_or(nb::Error::WouldBlock)
} }
} }
macro_rules! impl_spinlock {
($($spinlock_name:ident => $register:literal,)*) => {
$(
/// Hardware based spinlock.
///
/// You can claim this lock by calling either [`claim`], [`try_claim`] or [`claim_async`].
/// This will automatically lock ALL spinlocks of type `
#[doc = stringify!($spinlock_name)]
/// `.
///
/// When the obtained spinlock goes out of scope, it is automatically unlocked.
///
/// **warning**: These spinlocks are not re-entrant, meaning that the following code will cause a deadlock:
///
/// ```no_run
/// use rp2040_hal::sio::{Spinlock0, Spinlock};
/// let lock_1 = Spinlock0::claim();
/// let lock_2 = Spinlock0::claim(); // deadlock here
/// ```
///
/// [`claim`]: #method.claim
/// [`try_claim`]: #method.try_claim
/// [`claim_async`]: #method.claim_async
pub struct $spinlock_name(core::marker::PhantomData<()>);
impl Spinlock for $spinlock_name { impl<const N: usize> Drop for Spinlock<N>
fn try_claim() -> Option<$spinlock_name> { where
// Safety: We're only reading from this register Spinlock<N>: SpinlockValid,
let sio = unsafe { &*pac::SIO::ptr() }; {
let lock = sio.spinlock[$register].read().bits();
if lock > 0 {
Some(Self(core::marker::PhantomData))
} else {
None
}
}
}
impl typelevel::Sealed for $spinlock_name {}
impl Drop for $spinlock_name {
fn drop(&mut self) { fn drop(&mut self) {
// Safety: At this point we should be the only one accessing this spinlock register // Safety: At this point we should be the only one accessing this spinlock register
// so writing to this address is fine // so writing to this address is fine
let sio = unsafe { &*pac::SIO::ptr() }; let sio = unsafe { &*pac::SIO::ptr() };
// Write (any value): release the lock // Write (any value): release the lock
sio.spinlock[$register].write(|b| unsafe { b.bits(1) }); sio.spinlock[N].write(|b| unsafe { b.bits(1) });
}
}
)*
} }
} }
impl_spinlock! { /// Spinlock number 0
Spinlock0 => 0, pub type Spinlock0 = Spinlock<0>;
Spinlock1 => 1,
Spinlock2 => 2, impl SpinlockValid for Spinlock<0> {}
Spinlock3 => 3,
Spinlock4 => 4, /// Spinlock number 1
Spinlock5 => 5, pub type Spinlock1 = Spinlock<1>;
Spinlock6 => 6,
Spinlock7 => 7, impl SpinlockValid for Spinlock<1> {}
Spinlock8 => 8,
Spinlock9 => 9, /// Spinlock number 2
Spinlock10 => 10, pub type Spinlock2 = Spinlock<2>;
Spinlock11 => 11,
Spinlock12 => 12, impl SpinlockValid for Spinlock<2> {}
Spinlock13 => 13,
Spinlock14 => 14, /// Spinlock number 3
Spinlock15 => 15, pub type Spinlock3 = Spinlock<3>;
Spinlock16 => 16,
Spinlock17 => 17, impl SpinlockValid for Spinlock<3> {}
Spinlock18 => 18,
Spinlock19 => 19, /// Spinlock number 4
Spinlock20 => 20, pub type Spinlock4 = Spinlock<4>;
Spinlock21 => 21,
Spinlock22 => 22, impl SpinlockValid for Spinlock<4> {}
Spinlock23 => 23,
Spinlock24 => 24, /// Spinlock number 5
Spinlock25 => 25, pub type Spinlock5 = Spinlock<5>;
Spinlock26 => 26,
Spinlock27 => 27, impl SpinlockValid for Spinlock<5> {}
Spinlock28 => 28,
Spinlock29 => 29, /// Spinlock number 6
Spinlock30 => 30, pub type Spinlock6 = Spinlock<6>;
Spinlock31 => 31,
} impl SpinlockValid for Spinlock<6> {}
/// Spinlock number 7
pub type Spinlock7 = Spinlock<7>;
impl SpinlockValid for Spinlock<7> {}
/// Spinlock number 8
pub type Spinlock8 = Spinlock<8>;
impl SpinlockValid for Spinlock<8> {}
/// Spinlock number 9
pub type Spinlock9 = Spinlock<9>;
impl SpinlockValid for Spinlock<9> {}
/// Spinlock number 10
pub type Spinlock10 = Spinlock<10>;
impl SpinlockValid for Spinlock<10> {}
/// Spinlock number 11
pub type Spinlock11 = Spinlock<11>;
impl SpinlockValid for Spinlock<11> {}
/// Spinlock number 12
pub type Spinlock12 = Spinlock<12>;
impl SpinlockValid for Spinlock<12> {}
/// Spinlock number 13
pub type Spinlock13 = Spinlock<13>;
impl SpinlockValid for Spinlock<13> {}
/// Spinlock number 14
pub type Spinlock14 = Spinlock<14>;
impl SpinlockValid for Spinlock<14> {}
/// Spinlock number 15
pub type Spinlock15 = Spinlock<15>;
impl SpinlockValid for Spinlock<15> {}
/// Spinlock number 16
pub type Spinlock16 = Spinlock<16>;
impl SpinlockValid for Spinlock<16> {}
/// Spinlock number 17
pub type Spinlock17 = Spinlock<17>;
impl SpinlockValid for Spinlock<17> {}
/// Spinlock number 18
pub type Spinlock18 = Spinlock<18>;
impl SpinlockValid for Spinlock<18> {}
/// Spinlock number 19
pub type Spinlock19 = Spinlock<19>;
impl SpinlockValid for Spinlock<19> {}
/// Spinlock number 20
pub type Spinlock20 = Spinlock<20>;
impl SpinlockValid for Spinlock<20> {}
/// Spinlock number 21
pub type Spinlock21 = Spinlock<21>;
impl SpinlockValid for Spinlock<21> {}
/// Spinlock number 22
pub type Spinlock22 = Spinlock<22>;
impl SpinlockValid for Spinlock<22> {}
/// Spinlock number 23
pub type Spinlock23 = Spinlock<23>;
impl SpinlockValid for Spinlock<23> {}
/// Spinlock number 24
pub type Spinlock24 = Spinlock<24>;
impl SpinlockValid for Spinlock<24> {}
/// Spinlock number 25
pub type Spinlock25 = Spinlock<25>;
impl SpinlockValid for Spinlock<25> {}
/// Spinlock number 26
pub type Spinlock26 = Spinlock<26>;
impl SpinlockValid for Spinlock<26> {}
/// Spinlock number 27
pub type Spinlock27 = Spinlock<27>;
impl SpinlockValid for Spinlock<27> {}
/// Spinlock number 28
pub type Spinlock28 = Spinlock<28>;
impl SpinlockValid for Spinlock<28> {}
/// Spinlock number 29
pub type Spinlock29 = Spinlock<29>;
impl SpinlockValid for Spinlock<29> {}
/// Spinlock number 30
pub type Spinlock30 = Spinlock<30>;
impl SpinlockValid for Spinlock<30> {}
/// Spinlock number 31
pub type Spinlock31 = Spinlock<31>;
impl SpinlockValid for Spinlock<31> {}
/// Returns the current state of the spinlocks. Each index corresponds to the associated spinlock, e.g. if index `5` is set to `true`, it means that [`Spinlock5`] is currently locked. /// Returns the current state of the spinlocks. Each index corresponds to the associated spinlock, e.g. if index `5` is set to `true`, it means that [`Spinlock5`] is currently locked.
/// ///