79 lines
2.9 KiB
Rust
79 lines
2.9 KiB
Rust
//! Device tree node utilities
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use fdt_rs::{prelude::PropReader, spec::Phandle};
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use crate::{
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property::DeviceTreePropertyRead,
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tree::{DeviceTree, TNode, TProp},
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};
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/// Accessor trait for a device tree node
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pub trait DeviceTreeNodeExt<'a> {
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/// Looks up a property with given `name` in the node
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fn property(&self, name: &str) -> Option<TProp<'a>>;
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/// Looks up a child with given `name` in the node
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fn child(&self, name: &str) -> Option<TNode<'a>>;
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/// Looks up a property with given `name` in the nearest parent.
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fn parent_property(&self, name: &str) -> Option<TProp<'a>>;
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/// Returns a property `name`, interpreted as a single string value
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fn prop_string(&self, name: &str) -> Option<&'a str>;
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/// Returns a property `name`, interpreted as a cell of given `size`
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fn prop_cell(&self, name: &str, size: usize) -> Option<u64>;
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/// Returns a property `name`, interpreted as a single cell, cast to [usize]
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fn prop_cell_usize(&self, name: &str) -> Option<usize> {
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self.prop_cell(name, 1).map(|v| v as _)
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}
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/// Returns a property `name`, interpreted as a phandle
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fn prop_phandle(&self, name: &str) -> Option<Phandle> {
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self.prop_cell(name, 1).map(|v| v as _)
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}
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/// Returns `true` if the node contains a property `name`
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fn has_property(&self, name: &str) -> bool {
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self.property(name).is_some()
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}
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/// Returns the `#address-cells` value of the nearest parent
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fn parent_address_cells(&self) -> usize {
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self.parent_property("#address-cells")
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.and_then(|property| property.read_cell(0, 1))
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.unwrap_or(DeviceTree::DEFAULT_ADDRESS_CELLS as u64) as usize
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}
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/// Returns the `#size-cells` value of the nearest parent
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fn parent_size_cells(&self) -> usize {
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self.parent_property("#size-cells")
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.and_then(|property| property.read_cell(0, 1))
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.unwrap_or(DeviceTree::DEFAULT_SIZE_CELLS as u64) as usize
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}
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}
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impl<'a> DeviceTreeNodeExt<'a> for TNode<'a> {
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fn property(&self, name: &str) -> Option<TProp<'a>> {
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self.props()
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.find(|prop| prop.name().map(|n| n == name).unwrap_or(false))
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}
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fn child(&self, name: &str) -> Option<TNode<'a>> {
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self.children()
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.find(|child| child.name().map(|n| n == name).unwrap_or(false))
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}
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fn parent_property(&self, name: &str) -> Option<TProp<'a>> {
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let mut current = self.parent()?;
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loop {
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if let Some(property) = current.property(name) {
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return Some(property);
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}
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current = current.parent()?;
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}
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}
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fn prop_cell(&self, name: &str, size: usize) -> Option<u64> {
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self.property(name).and_then(|prop| prop.read_cell(0, size))
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}
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fn prop_string(&self, name: &str) -> Option<&'a str> {
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self.property(name).and_then(|prop| prop.str().ok())
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}
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}
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