mirror of https://github.com/m-labs/artiq.git
40 lines
982 B
Rust
40 lines
982 B
Rust
use core::ptr::{read_volatile, write_volatile};
|
|
use board_misoc::{mem, cache};
|
|
|
|
const MAILBOX: *mut usize = mem::MAILBOX_BASE as *mut usize;
|
|
static mut LAST: usize = 0;
|
|
|
|
pub unsafe fn send(data: usize) {
|
|
LAST = data;
|
|
// after Rust toolchain update to LLVM12, this empty asm! block is required
|
|
// to ensure that the compiler doesn't take any shortcuts
|
|
// otherwise, the comm CPU will read garbage data and crash
|
|
asm!("", options(preserves_flags, readonly, nostack));
|
|
write_volatile(MAILBOX, data);
|
|
}
|
|
|
|
pub fn acknowledged() -> bool {
|
|
unsafe {
|
|
let data = read_volatile(MAILBOX);
|
|
data == 0 || data != LAST
|
|
}
|
|
}
|
|
|
|
pub fn receive() -> usize {
|
|
unsafe {
|
|
let data = read_volatile(MAILBOX);
|
|
if data == LAST {
|
|
0
|
|
} else {
|
|
if data != 0 {
|
|
cache::flush_cpu_dcache()
|
|
}
|
|
data
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn acknowledge() {
|
|
unsafe { write_volatile(MAILBOX, 0) }
|
|
}
|