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//! Unsafe linked list.
//! Translated from ST's C by `c2rust` tool.
#![allow(
dead_code,
mutable_transmutes,
non_camel_case_types,
non_snake_case,
non_upper_case_globals,
unused_assignments,
unused_mut
)]
use core::ptr;
use cortex_m::interrupt;
#[derive(Copy, Clone)]
#[repr(C, packed(4))]
pub struct LinkedListNode {
pub next: *mut LinkedListNode,
pub prev: *mut LinkedListNode,
}
impl Default for LinkedListNode {
fn default() -> Self {
LinkedListNode {
next: core::ptr::null_mut(),
prev: core::ptr::null_mut(),
}
}
}
impl LinkedListNode {
pub unsafe fn init_head(mut p_list_head: *mut LinkedListNode) {
ptr::write_volatile(
p_list_head,
LinkedListNode {
next: p_list_head,
prev: p_list_head,
},
);
}
pub unsafe fn is_empty(mut p_list_head: *mut LinkedListNode) -> bool {
interrupt::free(|_| ptr::read_volatile(p_list_head).next == p_list_head)
}
/// Insert `node` after `list_head` and before the next node
pub unsafe fn insert_head(mut p_list_head: *mut LinkedListNode, mut p_node: *mut LinkedListNode) {
interrupt::free(|_| {
let mut list_head = ptr::read_volatile(p_list_head);
if p_list_head != list_head.next {
let mut node_next = ptr::read_volatile(list_head.next);
let node = LinkedListNode {
next: list_head.next,
prev: p_list_head,
};
list_head.next = p_node;
node_next.prev = p_node;
// All nodes must be written because they will all be seen by another core
ptr::write_volatile(p_node, node);
ptr::write_volatile(node.next, node_next);
ptr::write_volatile(p_list_head, list_head);
} else {
let node = LinkedListNode {
next: list_head.next,
prev: p_list_head,
};
list_head.next = p_node;
list_head.prev = p_node;
// All nodes must be written because they will all be seen by another core
ptr::write_volatile(p_node, node);
ptr::write_volatile(p_list_head, list_head);
}
});
}
/// Insert `node` before `list_tail` and after the second-to-last node
pub unsafe fn insert_tail(mut p_list_tail: *mut LinkedListNode, mut p_node: *mut LinkedListNode) {
interrupt::free(|_| {
let mut list_tail = ptr::read_volatile(p_list_tail);
if p_list_tail != list_tail.prev {
let mut node_prev = ptr::read_volatile(list_tail.prev);
let node = LinkedListNode {
next: p_list_tail,
prev: list_tail.prev,
};
list_tail.prev = p_node;
node_prev.next = p_node;
// All nodes must be written because they will all be seen by another core
ptr::write_volatile(p_node, node);
ptr::write_volatile(node.prev, node_prev);
ptr::write_volatile(p_list_tail, list_tail);
} else {
let node = LinkedListNode {
next: p_list_tail,
prev: list_tail.prev,
};
list_tail.prev = p_node;
list_tail.next = p_node;
// All nodes must be written because they will all be seen by another core
ptr::write_volatile(p_node, node);
ptr::write_volatile(p_list_tail, list_tail);
}
});
}
/// Remove `node` from the linked list
pub unsafe fn remove_node(mut p_node: *mut LinkedListNode) {
interrupt::free(|_| {
// trace!("remove node: {:x}", p_node);
// apparently linked list nodes are not always aligned.
// if more hardfaults occur, more of these may need to be converted to unaligned.
let node = ptr::read_unaligned(p_node);
// trace!("remove node: prev/next {:x}/{:x}", node.prev, node.next);
if node.next != node.prev {
let mut node_next = ptr::read_volatile(node.next);
let mut node_prev = ptr::read_volatile(node.prev);
node_prev.next = node.next;
node_next.prev = node.prev;
ptr::write_volatile(node.next, node_next);
ptr::write_volatile(node.prev, node_prev);
} else {
let mut node_next = ptr::read_volatile(node.next);
node_next.next = node.next;
node_next.prev = node.prev;
ptr::write_volatile(node.next, node_next);
}
});
}
/// Remove `list_head` and return a pointer to the `node`.
pub unsafe fn remove_head(mut p_list_head: *mut LinkedListNode) -> Option<*mut LinkedListNode> {
interrupt::free(|_| {
let list_head = ptr::read_volatile(p_list_head);
if list_head.next == p_list_head {
None
} else {
// Allowed because a removed node is not seen by another core
let p_node = list_head.next;
Self::remove_node(p_node);
Some(p_node)
}
})
}
/// Remove `list_tail` and return a pointer to the `node`.
pub unsafe fn remove_tail(mut p_list_tail: *mut LinkedListNode) -> Option<*mut LinkedListNode> {
interrupt::free(|_| {
let list_tail = ptr::read_volatile(p_list_tail);
if list_tail.prev == p_list_tail {
None
} else {
// Allowed because a removed node is not seen by another core
let p_node = list_tail.prev;
Self::remove_node(p_node);
Some(p_node)
}
})
}
pub unsafe fn insert_node_after(mut node: *mut LinkedListNode, mut ref_node: *mut LinkedListNode) {
interrupt::free(|_| {
(*node).next = (*ref_node).next;
(*node).prev = ref_node;
(*ref_node).next = node;
(*(*node).next).prev = node;
});
todo!("this function has not been converted to volatile semantics");
}
pub unsafe fn insert_node_before(mut node: *mut LinkedListNode, mut ref_node: *mut LinkedListNode) {
interrupt::free(|_| {
(*node).next = ref_node;
(*node).prev = (*ref_node).prev;
(*ref_node).prev = node;
(*(*node).prev).next = node;
});
todo!("this function has not been converted to volatile semantics");
}
pub unsafe fn get_size(mut list_head: *mut LinkedListNode) -> usize {
interrupt::free(|_| {
let mut size = 0;
let mut temp: *mut LinkedListNode = core::ptr::null_mut::<LinkedListNode>();
temp = (*list_head).next;
while temp != list_head {
size += 1;
temp = (*temp).next
}
size
});
todo!("this function has not been converted to volatile semantics");
}
pub unsafe fn get_next_node(mut p_ref_node: *mut LinkedListNode) -> *mut LinkedListNode {
interrupt::free(|_| {
let ref_node = ptr::read_volatile(p_ref_node);
// Allowed because a removed node is not seen by another core
ref_node.next
})
}
pub unsafe fn get_prev_node(mut p_ref_node: *mut LinkedListNode) -> *mut LinkedListNode {
interrupt::free(|_| {
let ref_node = ptr::read_volatile(p_ref_node);
// Allowed because a removed node is not seen by another core
ref_node.prev
})
}
}
#[allow(dead_code)]
unsafe fn debug_linked_list(mut p_node: *mut LinkedListNode) {
info!("iterating list from node: {:x}", p_node);
let mut p_current_node = p_node;
let mut i = 0;
loop {
let current_node = ptr::read_volatile(p_current_node);
info!(
"node (prev, current, next): {:x}, {:x}, {:x}",
current_node.prev, p_current_node, current_node.next
);
i += 1;
if i > 10 || current_node.next == p_node {
break;
}
p_current_node = current_node.next;
}
}
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