esp_hal/peripheral.rs
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//! # Exclusive peripheral access
use core::{
marker::PhantomData,
ops::{Deref, DerefMut},
};
/// An exclusive reference to a peripheral.
///
/// This is functionally the same as a `&'a mut T`. There's a few advantages in
/// having a dedicated struct instead:
///
/// - Memory efficiency: Peripheral singletons are typically either zero-sized
/// (for concrete peripherals like `GpioPin<5>` or `SPI2`) or very small (for
/// example `AnyPin`, which is 1 byte). However `&mut T` is always 4 bytes for
/// 32-bit targets, even if T is zero-sized. PeripheralRef stores a copy of
/// `T` instead, so it's the same size.
/// - Code size efficiency. If the user uses the same driver with both `SPI2`
/// and `&mut SPI2`, the driver code would be monomorphized two times. With
/// PeripheralRef, the driver is generic over a lifetime only. `SPI2` becomes
/// `PeripheralRef<'static, SPI2>`, and `&mut SPI2` becomes `PeripheralRef<'a,
/// SPI2>`. Lifetimes don't cause monomorphization.
#[derive(Debug)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub struct PeripheralRef<'a, T> {
inner: T,
_lifetime: PhantomData<&'a mut T>,
}
impl<'a, T> PeripheralRef<'a, T> {
/// Create a new exclusive reference to a peripheral
#[inline]
pub fn new(inner: T) -> Self {
Self {
inner,
_lifetime: PhantomData,
}
}
/// Unsafely clone (duplicate) a peripheral singleton.
///
/// # Safety
///
/// This returns an owned clone of the peripheral. You must manually ensure
/// only one copy of the peripheral is in use at a time. For example, don't
/// create two SPI drivers on `SPI1`, because they will "fight" each other.
///
/// You should strongly prefer using `reborrow()` instead. It returns a
/// `PeripheralRef` that borrows `self`, which allows the borrow checker
/// to enforce this at compile time.
pub unsafe fn clone_unchecked(&self) -> PeripheralRef<'a, T>
where
T: Peripheral<P = T>,
{
PeripheralRef::new(self.inner.clone_unchecked())
}
/// Reborrow into a "child" PeripheralRef.
///
/// `self` will stay borrowed until the child PeripheralRef is dropped.
pub fn reborrow(&mut self) -> PeripheralRef<'_, T>
where
T: Peripheral<P = T>,
{
// safety: we're returning the clone inside a new PeripheralRef that borrows
// self, so user code can't use both at the same time.
PeripheralRef::new(unsafe { self.inner.clone_unchecked() })
}
/// Transform the inner peripheral.
///
/// This converts from `PeripheralRef<'a, T>` to `PeripheralRef<'a, U>`,
/// using a user-provided impl to convert from `T` to `U`.
#[inline]
pub fn map<U>(self, transform: impl FnOnce(T) -> U) -> PeripheralRef<'a, U> {
PeripheralRef {
inner: transform(self.inner),
_lifetime: PhantomData,
}
}
/// Map the inner peripheral using `Into`.
///
/// This converts from `PeripheralRef<'a, T>` to `PeripheralRef<'a, U>`,
/// using an `Into` impl to convert from `T` to `U`.
///
/// For example, this can be useful to degrade GPIO pins: converting from
/// `PeripheralRef<'a, GpioPin<11>>` to `PeripheralRef<'a, AnyPin>`.
#[inline]
pub fn map_into<U>(self) -> PeripheralRef<'a, U>
where
T: Into<U>,
{
self.map(Into::into)
}
}
impl<T> Deref for PeripheralRef<'_, T> {
type Target = T;
#[inline]
fn deref(&self) -> &Self::Target {
&self.inner
}
}
/// Trait for any type that can be used as a peripheral of type `P`.
///
/// This is used in driver constructors, to allow passing either owned
/// peripherals (e.g. `UART0`), or borrowed peripherals (e.g. `&mut UART0`).
///
/// For example, if you have a driver with a constructor like this:
///
/// ```rust, ignore
/// impl<'d, T> Uart<'d, T, Blocking> {
/// pub fn new<TX: PeripheralOutput, RX: PeripheralInput>(
/// uart: impl Peripheral<P = T> + 'd,
/// rx: impl Peripheral<P = RX> + 'd,
/// tx: impl Peripheral<P = TX> + 'd,
/// ) -> Result<Self, Error> {
/// Ok(Self { .. })
/// }
/// }
/// ```
///
/// You may call it with owned peripherals, which yields an instance that can
/// live forever (`'static`):
///
/// ```rust, ignore
/// let mut uart: Uart<'static, ...> = Uart::new(p.UART0, p.GPIO0, p.GPIO1);
/// ```
///
/// Or you may call it with borrowed peripherals, which yields an instance that
/// can only live for as long as the borrows last:
///
/// ```rust, ignore
/// let mut uart: Uart<'_, ...> = Uart::new(&mut p.UART0, &mut p.GPIO0, &mut p.GPIO1);
/// ```
///
/// # Implementation details, for HAL authors
///
/// When writing a HAL, the intended way to use this trait is to take `impl
/// Peripheral<P = ..>` in the HAL's public API (such as driver constructors),
/// calling `.into_ref()` to obtain a `PeripheralRef`, and storing that in the
/// driver struct.
///
/// `.into_ref()` on an owned `T` yields a `PeripheralRef<'static, T>`.
/// `.into_ref()` on an `&'a mut T` yields a `PeripheralRef<'a, T>`.
pub trait Peripheral: Sized {
/// Peripheral singleton type
type P;
/// Unsafely clone (duplicate) a peripheral singleton.
///
/// # Safety
///
/// This returns an owned clone of the peripheral. You must manually ensure
/// only one copy of the peripheral is in use at a time. For example, don't
/// create two SPI drivers on `SPI1`, because they will "fight" each other.
///
/// You should strongly prefer using `into_ref()` instead. It returns a
/// `PeripheralRef`, which allows the borrow checker to enforce this at
/// compile time.
unsafe fn clone_unchecked(&self) -> Self::P;
/// Convert a value into a `PeripheralRef`.
///
/// When called on an owned `T`, yields a `PeripheralRef<'static, T>`.
/// When called on an `&'a mut T`, yields a `PeripheralRef<'a, T>`.
#[inline]
fn into_ref<'a>(self) -> PeripheralRef<'a, Self::P>
where
Self: 'a,
{
PeripheralRef::new(unsafe { self.clone_unchecked() })
}
/// Map the peripheral using `Into`.
///
/// This converts from `Peripheral<P = T>` to `Peripheral<P = U>`,
/// using an `Into` impl to convert from `T` to `U`.
#[inline]
fn map_into<U>(self) -> U
where
Self::P: Into<U>,
U: Peripheral<P = U>,
{
self.map(Into::into)
}
/// Map the peripheral using `Into`.
///
/// This converts from `Peripheral<P = T>` to `Peripheral<P = U>`,
/// using an `Into` impl to convert from `T` to `U`.
#[inline]
fn map<U>(self, transform: impl FnOnce(Self::P) -> U) -> U
where
U: Peripheral<P = U>,
{
transform(unsafe { self.clone_unchecked() })
}
}
impl<T: DerefMut> Peripheral for T
where
T::Target: Peripheral,
{
type P = <T::Target as Peripheral>::P;
#[inline]
unsafe fn clone_unchecked(&self) -> Self::P {
T::Target::clone_unchecked(self)
}
}
impl<T: Peripheral> Peripheral for PeripheralRef<'_, T> {
type P = T::P;
#[inline]
unsafe fn clone_unchecked(&self) -> Self::P {
T::clone_unchecked(self)
}
}
mod peripheral_macros {
/// Creates a new `Peripherals` struct and its associated methods.
///
/// The macro has a few fields doing different things, in the form of
/// `second <= third (fourth)`.
/// - The second field is the name of the peripheral, as it appears in the
/// `Peripherals` struct.
/// - The third field is the name of the peripheral as it appears in the
/// PAC. This may be `virtual` if the peripheral is not present in the
/// PAC.
/// - The fourth field is an optional list of interrupts that can be bound
/// to the peripheral.
#[doc(hidden)]
#[macro_export]
macro_rules! peripherals {
(
peripherals: [
$(
$name:ident <= $from_pac:tt $(($($interrupt:ident),*))?
),* $(,)?
],
unstable_peripherals: [
$(
$unstable_name:ident <= $unstable_from_pac:tt $(($($unstable_interrupt:ident),*))?
),* $(,)?
],
pins: [
$( ( $pin:literal, $($pin_tokens:tt)* ) )*
],
dma_channels: [
$(
$channel_name:ident : $channel_ty:path
),* $(,)?
]
) => {
$(
$crate::create_peripheral!($name <= $from_pac);
)*
$(
$crate::create_peripheral!(#[instability::unstable] $unstable_name <= $unstable_from_pac);
)*
pub(crate) mod gpio {
$crate::gpio! {
$( ($pin, $($pin_tokens)* ) )*
}
}
paste::paste! {
/// The `Peripherals` struct provides access to all of the hardware peripherals on the chip.
#[allow(non_snake_case)]
pub struct Peripherals {
$(
#[doc = concat!("The ", stringify!($name), " peripheral.")]
pub $name: $name,
)*
$(
#[doc = concat!("The ", stringify!($unstable_name), " peripheral.")]
#[doc = "**This API is marked as unstable** and is only available when the `unstable`
crate feature is enabled. This comes with no stability guarantees, and could be changed
or removed at any time."]
#[cfg(any(doc, feature = "unstable"))]
#[cfg_attr(docsrs, doc(cfg(feature = "unstable")))]
pub $unstable_name: $unstable_name,
#[doc = concat!("The ", stringify!($unstable_name), " peripheral.")]
#[doc = "**This API is marked as unstable** and is only available when the `unstable`
crate feature is enabled. This comes with no stability guarantees, and could be changed
or removed at any time."]
#[cfg(not(any(doc, feature = "unstable")))]
#[allow(unused)]
pub(crate) $unstable_name: $unstable_name,
)*
$(
#[doc = concat!("GPIO", stringify!($pin))]
pub [<GPIO $pin>]: $crate::gpio::GpioPin<$pin>,
)*
$(
#[doc = concat!(stringify!($channel_name), " DMA channel.")]
pub $channel_name: $crate::dma::$channel_ty,
)*
}
impl Peripherals {
/// Returns all the peripherals *once*
#[inline]
pub(crate) fn take() -> Self {
#[no_mangle]
static mut _ESP_HAL_DEVICE_PERIPHERALS: bool = false;
critical_section::with(|_| unsafe {
if _ESP_HAL_DEVICE_PERIPHERALS {
panic!("init called more than once!")
}
_ESP_HAL_DEVICE_PERIPHERALS = true;
Self::steal()
})
}
/// Unsafely create an instance of this peripheral out of thin air.
///
/// # Safety
///
/// You must ensure that you're only using one instance of this type at a time.
#[inline]
pub unsafe fn steal() -> Self {
Self {
$(
$name: $name::steal(),
)*
$(
$unstable_name: $unstable_name::steal(),
)*
$(
[<GPIO $pin>]: $crate::gpio::GpioPin::<$pin>::steal(),
)*
$(
$channel_name: $crate::dma::$channel_ty::steal(),
)*
}
}
}
}
$(
$(
impl $name {
$(
paste::paste!{
/// Binds an interrupt handler to the corresponding interrupt for this peripheral.
#[instability::unstable]
pub fn [<bind_ $interrupt:lower _interrupt >](&mut self, handler: unsafe extern "C" fn() -> ()) {
unsafe { $crate::interrupt::bind_interrupt($crate::peripherals::Interrupt::$interrupt, handler); }
}
}
)*
}
)*
)*
$(
$(
impl $unstable_name {
$(
paste::paste!{
/// Binds an interrupt handler to the corresponding interrupt for this peripheral.
#[instability::unstable]
pub fn [<bind_ $unstable_interrupt:lower _interrupt >](&mut self, handler: unsafe extern "C" fn() -> ()) {
unsafe { $crate::interrupt::bind_interrupt($crate::peripherals::Interrupt::$unstable_interrupt, handler); }
}
}
)*
}
)*
)*
};
}
#[doc(hidden)]
#[macro_export]
macro_rules! into_ref {
($($name:ident),*) => {
$(
#[allow(unused_mut)]
let mut $name = $name.into_ref();
)*
}
}
#[doc(hidden)]
#[macro_export]
macro_rules! into_mapped_ref {
($($name:ident),*) => {
$(
#[allow(unused_mut)]
let mut $name = $name.map_into().into_ref();
)*
}
}
#[doc(hidden)]
#[macro_export]
/// Macro to create a peripheral structure.
macro_rules! create_peripheral {
($(#[$attr:meta])? $name:ident <= virtual) => {
$(#[$attr])?
#[derive(Debug)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
#[non_exhaustive]
#[allow(non_camel_case_types, clippy::upper_case_acronyms)]
#[doc = concat!(stringify!($name), " peripheral singleton")]
pub struct $name;
impl $name {
/// Unsafely create an instance of this peripheral out of thin air.
///
/// # Safety
///
/// You must ensure that you're only using one instance of this type at a time.
#[inline]
pub unsafe fn steal() -> Self {
Self
}
}
impl $crate::peripheral::Peripheral for $name {
type P = $name;
#[inline]
unsafe fn clone_unchecked(&self) -> Self::P {
Self::steal()
}
}
impl $crate::private::Sealed for $name {}
};
($(#[$attr:meta])? $name:ident <= $base:ident) => {
$crate::create_peripheral!($(#[$attr])? $name <= virtual);
impl $name {
#[doc = r"Pointer to the register block"]
#[instability::unstable]
pub const PTR: *const <pac::$base as core::ops::Deref>::Target = pac::$base::PTR;
#[doc = r"Return the pointer to the register block"]
#[inline(always)]
#[instability::unstable]
pub const fn ptr() -> *const <pac::$base as core::ops::Deref>::Target {
pac::$base::PTR
}
#[doc = r"Return a reference to the register block"]
#[inline(always)]
#[instability::unstable]
pub const fn regs<'a>() -> &'a <pac::$base as core::ops::Deref>::Target {
unsafe { &*Self::PTR }
}
#[doc = r"Return a reference to the register block"]
#[inline(always)]
#[instability::unstable]
pub fn register_block(&self) -> &<pac::$base as core::ops::Deref>::Target {
unsafe { &*Self::PTR }
}
}
};
}
}