21a21c6a11
This makes it easier to work with device tree nodes and properties, then writing simple state machines to parse the device tree. This also makes the old slow traversal methods use the DeviceTreeProperty helper class, and adds a simple test.
67 lines
2.9 KiB
C++
67 lines
2.9 KiB
C++
/*
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* Copyright (c) 2021-2023, Andrew Kaster <akaster@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Endian.h>
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#include <AK/Error.h>
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#include <AK/Function.h>
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#include <AK/IterationDecision.h>
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#include <AK/StringView.h>
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#include <AK/Types.h>
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#include "DeviceTree.h"
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namespace DeviceTree {
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// https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html
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struct FlattenedDeviceTreeHeader {
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BigEndian<u32> magic; // 0xDOODFEED (BE)
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BigEndian<u32> totalsize; // Total size of entire blob including padding b/w and after fields
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BigEndian<u32> off_dt_struct; // Offset of StructureBlock from beginning of header
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// https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html#sect-fdt-structure-block
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BigEndian<u32> off_dt_strings; // Offset of StringsBlock from beginning of header
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// https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html#sect-fdt-strings-block
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BigEndian<u32> off_mem_rsvmap; // Offset of MemoryReservationBlock from beginning of header
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BigEndian<u32> version; // 0.3 spec defines version 17
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BigEndian<u32> last_comp_version; // 0.3 spec back-compatible with version 16, mandated to be 16
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BigEndian<u32> boot_cpuid_phys; // Physical ID given in `reg` property of CPU node of boot cpu
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BigEndian<u32> size_dt_strings; // Length in bytes of StringsBlock
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BigEndian<u32> size_dt_struct; // Length in bytes of StructureBlock
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};
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static_assert(sizeof(FlattenedDeviceTreeHeader) == 40, "FDT Header size must match specification");
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// https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html#format
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struct FlattenedDeviceTreeReserveEntry {
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BigEndian<u64> address;
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BigEndian<u64> size;
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bool operator==(FlattenedDeviceTreeReserveEntry const& other) const { return other.address == address && other.size == size; }
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};
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static_assert(sizeof(FlattenedDeviceTreeReserveEntry) == 16, "FDT Memory Reservation entry size must match specification");
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// https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html#lexical-structure
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enum FlattenedDeviceTreeTokenType : u32 {
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BeginNode = 1,
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EndNode = 2,
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Property = 3,
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NoOp = 4,
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End = 9
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};
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struct DeviceTreeCallbacks {
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Function<ErrorOr<IterationDecision>(StringView)> on_node_begin;
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Function<ErrorOr<IterationDecision>(StringView)> on_node_end;
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Function<ErrorOr<IterationDecision>(StringView, ReadonlyBytes)> on_property;
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Function<ErrorOr<IterationDecision>()> on_noop;
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Function<ErrorOr<void>()> on_end;
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};
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ErrorOr<void> walk_device_tree(FlattenedDeviceTreeHeader const&, ReadonlyBytes raw_device_tree, DeviceTreeCallbacks);
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ErrorOr<DeviceTreeProperty> slow_get_property(StringView name, FlattenedDeviceTreeHeader const&, ReadonlyBytes raw_device_tree);
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} // namespace DeviceTree
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