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libcortex_a9: add sync_channel

This commit is contained in:
Astro 2020-04-09 02:49:24 +02:00
parent 64771bf233
commit e54edbf32d
3 changed files with 136 additions and 48 deletions

View File

@ -5,7 +5,7 @@ extern crate alloc;
use core::{mem::transmute, task::Poll};
use alloc::{borrow::ToOwned, collections::BTreeMap, format};
use libcortex_a9::mutex::Mutex;
use libcortex_a9::{mutex::Mutex, sync_channel::{self, sync_channel}};
use libboard_zynq::{
print, println,
self as zynq, clocks::Clocks, clocks::source::{ClockSource, ArmPll, IoPll},
@ -134,17 +134,22 @@ pub fn main_core0() {
println!("{} bytes stack for core1", core1_stack.len());
let core1 = boot::Core1::start(core1_stack);
for _ in 0..0x1000000 {
let mut l = SHARED.lock();
*l += 1;
}
while !*DONE.lock() {
let x = { *SHARED.lock() };
println!("shared: {:08X}", x);
}
let x = { *SHARED.lock() };
println!("done shared: {:08X}", x);
let (tx, mut rx) = sync_channel(1000);
*SHARED.lock() = Some(tx);
let mut i = 0u32;
loop {
let r = rx.recv();
// println!("Recvd {}", r);
if i != *r {
println!("Expected {}, received {}", i, r);
}
if i % 100000 == 0 {
println!("{} Ok", i);
}
i += 1;
}
core1.reset();
libcortex_a9::asm::dsb();
@ -246,51 +251,27 @@ pub fn main_core0() {
time += 1;
Instant::from_millis(time)
});
// loop {
// time += 1;
// let timestamp = Instant::from_millis(time);
// match iface.poll(&mut sockets, timestamp) {
// Ok(_) => {},
// Err(e) => {
// println!("poll error: {}", e);
// }
// }
// // (mostly) taken from smoltcp example: TCP echo server
// let mut socket = sockets.get::<TcpSocket>(tcp_handle);
// if !socket.is_open() {
// socket.listen(TCP_PORT).unwrap()
// }
// if socket.may_recv() && socket.can_send() {
// socket.recv(|buf| {
// let len = buf.len().min(4096);
// let buffer = buf[..len].iter().cloned().collect::<Vec<_>>();
// (len, buffer)
// })
// .and_then(|buffer| socket.send_slice(&buffer[..]))
// .map(|_| {})
// .unwrap_or_else(|e| println!("tcp: {:?}", e));
// }
// }
// #[allow(unreachable_code)]
// drop(tx_descs);
// #[allow(unreachable_code)]
// drop(tx_buffers);
}
static SHARED: Mutex<u32> = Mutex::new(0);
static SHARED: Mutex<Option<sync_channel::Sender<u32>>> = Mutex::new(None);
static DONE: Mutex<bool> = Mutex::new(false);
#[no_mangle]
pub fn main_core1() {
println!("Hello from core1!");
for _ in 0..0x1000000 {
let mut l = SHARED.lock();
*l += 1;
let mut tx = None;
while tx.is_none() {
tx = SHARED.lock().take();
}
println!("Core1 got tx");
let mut tx = tx.unwrap();
for i in 0.. {
// println!("S {}", i);
tx.send(i);
}
println!("core1 done!");
*DONE.lock() = true;

View File

@ -2,10 +2,13 @@
#![feature(asm, global_asm)]
#![feature(never_type)]
extern crate alloc;
pub mod asm;
pub mod regs;
pub mod cache;
pub mod mmu;
pub mod mutex;
pub mod sync_channel;
global_asm!(include_str!("exceptions.s"));

View File

@ -0,0 +1,104 @@
use core::{
ptr::null_mut,
sync::atomic::{AtomicPtr, Ordering},
};
use alloc::{
boxed::Box,
sync::Arc,
vec::Vec,
};
use super::asm::*;
type Channel<T> = Vec<AtomicPtr<T>>;
/// Create a bounded channel
///
/// Returns `(tx, rx)` where one should be used one the local core,
/// and the other is to be shared with another core.
pub fn sync_channel<T>(bound: usize) -> (Sender<T>, Receiver<T>) {
// allow for bound=0
let len = bound + 1;
let mut channel = Vec::with_capacity(len);
for _ in 0..len {
channel.push(AtomicPtr::default());
}
let channel = Arc::new(channel);
let sender = Sender {
channel: channel.clone(),
pos: 0,
};
let receiver = Receiver {
channel: channel,
pos: 0,
};
(sender, receiver)
}
/// Sending half of a channel
pub struct Sender<T> {
channel: Arc<Channel<T>>,
pos: usize,
}
impl<T> Sender<T> {
/// Blocking send
pub fn send<B: Into<Box<T>>>(&mut self, content: B) {
let ptr = Box::into_raw(content.into());
let entry = &self.channel[self.pos];
// try to write the new pointer if the current pointer is
// NULL, retrying while it is not NULL
while entry.compare_and_swap(null_mut(), ptr, Ordering::Acquire) != null_mut() {
// power-saving
wfe();
}
dsb();
// wake power-saving receivers
sev();
// advance
self.pos += 1;
// wrap
if self.pos >= self.channel.len() {
self.pos = 0;
}
}
}
/// Receiving half of a channel
pub struct Receiver<T> {
channel: Arc<Channel<T>>,
pos: usize,
}
impl<T> Receiver<T> {
/// Blocking receive
pub fn recv(&mut self) -> Box<T> {
let entry = &self.channel[self.pos];
loop {
dmb();
let ptr = entry.swap(null_mut(), Ordering::Release);
if ptr != null_mut() {
dsb();
// wake power-saving senders
sev();
let content = unsafe { Box::from_raw(ptr) };
// advance
self.pos += 1;
// wrap
if self.pos >= self.channel.len() {
self.pos = 0;
}
return content;
}
// power-saving
wfe();
}
}
}