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Merge pull request #311 from Liamolucko/multicore-no-alloc

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Remove the `alloc` requirement for `Core::spawn`
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9names 2022-06-01 20:52:11 +10:00 committed by GitHub
parent e9f367f26c e9534ace04
commit d66b47920e
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4 changed files with 227 additions and 87 deletions
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1
rp2040-hal/Cargo.toml
View file

@ -42,7 +42,6 @@ dht-sensor = "0.2.1"
[features]
rt = ["rp2040-pac/rt"]
alloc = []
rom-func-cache = []
disable-intrinsics = []
rom-v2-intrinsics = []

17
rp2040-hal/examples/multicore_fifo_blink.rs
View file

@ -57,7 +57,7 @@ const CORE1_TASK_COMPLETE: u32 = 0xEE;
/// the stack guard to take up the least amount of usable RAM.
static mut CORE1_STACK: Stack<4096> = Stack::new();
fn core1_task() -> ! {
fn core1_task(sys_freq: u32) -> ! {
let mut pac = unsafe { pac::Peripherals::steal() };
let core = unsafe { pac::CorePeripherals::steal() };
@ -70,10 +70,6 @@ fn core1_task() -> ! {
);
let mut led_pin = pins.gpio25.into_push_pull_output();
// The first thing core0 sends us is the system bus frequency.
// The systick is based on this frequency, so we need that to
// be accurate when sleeping via cortex_m::delay::Delay
let sys_freq = sio.fifo.read_blocking();
let mut delay = cortex_m::delay::Delay::new(core.SYST, sys_freq);
loop {
let input = sio.fifo.read();
@ -114,17 +110,18 @@ fn main() -> ! {
.ok()
.unwrap();
let sys_freq = clocks.system_clock.freq().integer();
// The single-cycle I/O block controls our GPIO pins
let mut sio = hal::sio::Sio::new(pac.SIO);
let mut mc = Multicore::new(&mut pac.PSM, &mut pac.PPB, &mut sio);
let mut mc = Multicore::new(&mut pac.PSM, &mut pac.PPB, &mut sio.fifo);
let cores = mc.cores();
let core1 = &mut cores[1];
let _test = core1.spawn(core1_task, unsafe { &mut CORE1_STACK.mem });
let _test = core1.spawn(unsafe { &mut CORE1_STACK.mem }, move || {
core1_task(sys_freq)
});
// Let core1 know how fast the system clock is running
let sys_freq = clocks.system_clock.freq().integer();
sio.fifo.write_blocking(sys_freq);
/// How much we adjust the LED period every cycle
const LED_PERIOD_INCREMENT: i32 = 2;

133
rp2040-hal/examples/multicore_polyblink.rs Normal file
View file

@ -0,0 +1,133 @@
//! # Multicore Blinking Example
//!
//! This application blinks two LEDs on GPIOs 2 and 3 at different rates (3Hz
//! and 4Hz respectively.)
//!
//! See the `Cargo.toml` file for Copyright and licence details.
#![no_std]
#![no_main]
use cortex_m::delay::Delay;
// The macro for our start-up function
use cortex_m_rt::entry;
use embedded_time::fixed_point::FixedPoint;
use hal::clocks::Clock;
use hal::gpio::Pins;
use hal::multicore::{Multicore, Stack};
use hal::sio::Sio;
// Ensure we halt the program on panic (if we don't mention this crate it won't
// be linked)
use panic_halt as _;
// Alias for our HAL crate
use rp2040_hal as hal;
// A shorter alias for the Peripheral Access Crate, which provides low-level
// register access
use hal::pac;
// Some traits we need
use embedded_hal::digital::v2::ToggleableOutputPin;
/// The linker will place this boot block at the start of our program image. We
/// need this to help the ROM bootloader get our code up and running.
#[link_section = ".boot2"]
#[used]
pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_W25Q080;
/// External high-speed crystal on the Raspberry Pi Pico board is 12 MHz. Adjust
/// if your board has a different frequency
const XTAL_FREQ_HZ: u32 = 12_000_000u32;
/// The frequency at which core 0 will blink its LED (Hz).
const CORE0_FREQ: u32 = 3;
/// The frequency at which core 1 will blink its LED (Hz).
const CORE1_FREQ: u32 = 4;
/// The delay between each toggle of core 0's LED (us).
const CORE0_DELAY: u32 = 1_000_000 / CORE0_FREQ;
/// The delay between each toggle of core 1's LED (us).
const CORE1_DELAY: u32 = 1_000_000 / CORE1_FREQ;
/// Stack for core 1
///
/// Core 0 gets its stack via the normal route - any memory not used by static
/// values is reserved for stack and initialised by cortex-m-rt.
/// To get the same for Core 1, we would need to compile everything seperately
/// and modify the linker file for both programs, and that's quite annoying.
/// So instead, core1.spawn takes a [usize] which gets used for the stack.
/// NOTE: We use the `Stack` struct here to ensure that it has 32-byte
/// alignment, which allows the stack guard to take up the least amount of
/// usable RAM.
static mut CORE1_STACK: Stack<4096> = Stack::new();
/// Entry point to our bare-metal application.
///
/// The `#[entry]` macro ensures the Cortex-M start-up code calls this function
/// as soon as all global variables are initialised.
#[entry]
fn main() -> ! {
// Grab our singleton objects
let mut pac = pac::Peripherals::take().unwrap();
let core = pac::CorePeripherals::take().unwrap();
// Set up the watchdog driver - needed by the clock setup code
let mut watchdog = hal::watchdog::Watchdog::new(pac.WATCHDOG);
// Configure the clocks
let clocks = hal::clocks::init_clocks_and_plls(
XTAL_FREQ_HZ,
pac.XOSC,
pac.CLOCKS,
pac.PLL_SYS,
pac.PLL_USB,
&mut pac.RESETS,
&mut watchdog,
)
.ok()
.unwrap();
// Set up the GPIO pins
let mut sio = Sio::new(pac.SIO);
let pins = Pins::new(
pac.IO_BANK0,
pac.PADS_BANK0,
sio.gpio_bank0,
&mut pac.RESETS,
);
let mut led1 = pins.gpio2.into_push_pull_output();
let mut led2 = pins.gpio3.into_push_pull_output();
// Set up the delay for the first core.
let sys_freq = clocks.system_clock.freq().integer();
let mut delay = Delay::new(core.SYST, sys_freq);
// Start up the second core to blink the second LED
let mut mc = Multicore::new(&mut pac.PSM, &mut pac.PPB, &mut sio.fifo);
let cores = mc.cores();
let core1 = &mut cores[1];
core1
.spawn(unsafe { &mut CORE1_STACK.mem }, move || {
// Get the second core's copy of the `CorePeripherals`, which are per-core.
// Unfortunately, `cortex-m` doesn't support this properly right now,
// so we have to use `steal`.
let core = unsafe { pac::CorePeripherals::steal() };
// Set up the delay for the second core.
let mut delay = Delay::new(core.SYST, sys_freq);
// Blink the second LED.
loop {
led2.toggle().unwrap();
delay.delay_us(CORE1_DELAY)
}
})
.unwrap();
// Blink the first LED.
loop {
led1.toggle().unwrap();
delay.delay_us(CORE0_DELAY)
}
}
// End of file

163
rp2040-hal/src/multicore.rs
View file

@ -3,29 +3,30 @@
//! This module handles setup of the 2nd cpu core on the rp2040, which we refer to as core1.
//! It provides functionality for setting up the stack, and starting core1.
//!
//! The options for an entrypoint for core1 are
//! - a function that never returns - eg
//! `fn core1_task() -> ! { loop{} }; `
//! - a lambda (note: This requires a global allocator which requires a nightly compiler. Not recommended for beginners)
//! The entrypoint for core1 can be any function that never returns, including closures.
//!
//! # Usage
//!
//! ```no_run
//! use rp2040_hal::{pac, gpio::Pins, sio::Sio, multicore::{Multicore, Stack}};
//!
//! static mut CORE1_STACK: Stack<4096> = Stack::new();
//!
//! fn core1_task() -> ! {
//! loop{}
//! loop {}
//! }
//! // fn main() -> ! {
//! use rp2040_hal::{pac, gpio::Pins, sio::Sio, multicore::{Multicore, Stack}};
//!
//! fn main() -> ! {
//! let mut pac = pac::Peripherals::take().unwrap();
//! let mut sio = Sio::new(pac.SIO);
//! // Other init code above this line
//! let mut mc = Multicore::new(&mut pac.PSM, &mut pac.PPB, &mut sio);
//! let mut mc = Multicore::new(&mut pac.PSM, &mut pac.PPB, &mut sio.fifo);
//! let cores = mc.cores();
//! let core1 = &mut cores[1];
//! let _test = core1.spawn(core1_task, unsafe { &mut CORE1_STACK.mem });
//! let _test = core1.spawn(unsafe { &mut CORE1_STACK.mem }, core1_task);
//! // The rest of your application below this line
//! //}
//! # loop {}
//! }
//!
//! ```
//!
@ -33,10 +34,12 @@
//!
//! For a detailed example, see [examples/multicore_fifo_blink.rs](https://github.com/rp-rs/rp-hal/tree/main/rp2040-hal/examples/multicore_fifo_blink.rs)
use crate::pac;
use core::mem::ManuallyDrop;
use core::sync::atomic::compiler_fence;
use core::sync::atomic::Ordering;
#[cfg(feature = "alloc")]
extern crate alloc;
use crate::pac;
use crate::Sio;
/// Errors for multicore operations.
#[derive(Debug)]
@ -47,15 +50,6 @@ pub enum Error {
Unresponsive,
}
// We pass data to cores via the stack, so we read
// the data off the stack and into parameters that
// rust can read here. Ideally this would be a
// #[naked] function but that is not stable yet.
static MULTICORE_TRAMPOLINE: [u16; 2] = [
0xbd03, // pop {r0, r1, pc} - call wrapper (pc) with r0 and r1
0x46c0, // nop - pad this out to 32 bits long
];
#[inline(always)]
fn install_stack_guard(stack_bottom: *mut usize) {
let core = unsafe { pac::CorePeripherals::steal() };
@ -109,7 +103,11 @@ impl<const SIZE: usize> Stack<SIZE> {
impl<'p> Multicore<'p> {
/// Create a new |Multicore| instance.
pub fn new(psm: &'p mut pac::PSM, ppb: &'p mut pac::PPB, sio: &'p mut crate::Sio) -> Self {
pub fn new(
psm: &'p mut pac::PSM,
ppb: &'p mut pac::PPB,
sio: &'p mut crate::sio::SioFifo,
) -> Self {
Self {
cores: [
Core { inner: None },
@ -128,7 +126,11 @@ impl<'p> Multicore<'p> {
/// A handle for controlling a logical core.
pub struct Core<'p> {
inner: Option<(&'p mut pac::PSM, &'p mut pac::PPB, &'p mut crate::Sio)>,
inner: Option<(
&'p mut pac::PSM,
&'p mut pac::PPB,
&'p mut crate::sio::SioFifo,
)>,
}
impl<'p> Core<'p> {
@ -140,13 +142,36 @@ impl<'p> Core<'p> {
}
}
fn inner_spawn(
&mut self,
wrapper: *mut (),
entry: *mut (),
stack: &'static mut [usize],
) -> Result<(), Error> {
if let Some((psm, ppb, sio)) = self.inner.as_mut() {
/// Spawn a function on this core.
pub fn spawn<F>(&mut self, stack: &'static mut [usize], entry: F) -> Result<(), Error>
where
F: FnOnce() -> bad::Never + Send + 'static,
{
if let Some((psm, ppb, fifo)) = self.inner.as_mut() {
// The first two ignored `u64` parameters are there to take up all of the registers,
// which means that the rest of the arguments are taken from the stack,
// where we're able to put them from core 0.
extern "C" fn core1_startup<F: FnOnce() -> bad::Never>(
_: u64,
_: u64,
entry: &mut ManuallyDrop<F>,
stack_bottom: *mut usize,
) -> ! {
core1_setup(stack_bottom);
let entry = unsafe { ManuallyDrop::take(entry) };
// Signal that it's safe for core 0 to get rid of the original value now.
//
// We don't have any way to get at core 1's SIO without using `Peripherals::steal` right now,
// since svd2rust doesn't really support multiple cores properly.
let peripherals = unsafe { pac::Peripherals::steal() };
let mut sio = Sio::new(peripherals.SIO);
sio.fifo.write_blocking(1);
entry()
}
// Reset the core
psm.frce_off.modify(|_, w| w.proc1().set_bit());
while !psm.frce_off.read().proc1().bit_is_set() {
@ -157,14 +182,28 @@ impl<'p> Core<'p> {
// Set up the stack
let mut stack_ptr = unsafe { stack.as_mut_ptr().add(stack.len()) };
let mut push = |v: usize| unsafe {
stack_ptr = stack_ptr.sub(1);
stack_ptr.write(v);
};
// We don't want to drop this, since it's getting moved to the other core.
let mut entry = ManuallyDrop::new(entry);
push(wrapper as usize);
push(stack.as_mut_ptr() as usize);
push(entry as usize);
// Push the arguments to `core1_startup` onto the stack.
unsafe {
// Push `stack_bottom`.
stack_ptr = stack_ptr.sub(1);
stack_ptr.cast::<*mut usize>().write(stack.as_mut_ptr());
// Push `entry`.
stack_ptr = stack_ptr.sub(1);
stack_ptr.cast::<&mut ManuallyDrop<F>>().write(&mut entry);
}
// Make sure the compiler does not reorder the stack writes after to after the
// below FIFO writes, which would result in them not being seen by the second
// core.
//
// From the compiler perspective, this doesn't guarantee that the second core
// actually sees those writes. However, we know that the RP2040 doesn't have
// memory caches, and writes happen in-order.
compiler_fence(Ordering::Release);
let vector_table = ppb.vtor.read().bits();
@ -176,7 +215,7 @@ impl<'p> Core<'p> {
1,
vector_table as usize,
stack_ptr as usize,
MULTICORE_TRAMPOLINE.as_ptr() as usize + 1,
core1_startup::<F> as usize,
];
let mut seq = 0;
@ -184,17 +223,20 @@ impl<'p> Core<'p> {
loop {
let cmd = cmd_seq[seq] as u32;
if cmd == 0 {
sio.fifo.drain();
fifo.drain();
cortex_m::asm::sev();
}
sio.fifo.write_blocking(cmd);
let response = sio.fifo.read_blocking();
fifo.write_blocking(cmd);
let response = fifo.read_blocking();
if cmd == response {
seq += 1;
} else {
seq = 0;
fails += 1;
if fails > 16 {
// The second core isn't responding, and isn't going to take the entrypoint,
// so we have to drop it ourselves.
drop(ManuallyDrop::into_inner(entry));
return Err(Error::Unresponsive);
}
}
@ -203,48 +245,17 @@ impl<'p> Core<'p> {
}
}
// Wait until the other core has copied `entry` before returning.
fifo.read_blocking();
Ok(())
} else {
Err(Error::InvalidCore)
}
}
/// Spawn a function on this core.
#[cfg(not(feature = "alloc"))]
pub fn spawn(&mut self, entry: fn() -> !, stack: &'static mut [usize]) -> Result<(), Error> {
#[allow(improper_ctypes_definitions)]
extern "C" fn core1_no_alloc(entry: fn() -> !, stack_bottom: *mut usize) -> ! {
core1_setup(stack_bottom);
entry();
}
self.inner_spawn(core1_no_alloc as _, entry as _, stack)
}
/// Spawn a function on this core.
#[cfg(feature = "alloc")]
pub fn spawn<F>(&mut self, entry: F, stack: &'static mut [usize]) -> Result<(), Error>
where
F: FnOnce() -> bad::Never,
F: Send + 'static,
{
use alloc::boxed::Box;
let main: Box<dyn FnOnce() -> bad::Never> = Box::new(move || entry());
let p = Box::into_raw(Box::new(main));
extern "C" fn core1_alloc(entry: *mut (), stack_bottom: *mut usize) -> ! {
core1_setup(stack_bottom);
let main = unsafe { Box::from_raw(entry as *mut Box<dyn FnOnce() -> bad::Never>) };
main();
}
self.inner_spawn(core1_alloc as _, p as _, stack)
}
}
// https://github.com/nvzqz/bad-rs/blob/master/src/never.rs
#[cfg(feature = "alloc")]
mod bad {
pub(crate) type Never = <F as HasOutput>::Output;