fdt.c: node-scoped lookup extension (FABRIC-3.md SSIV.3/SSV.3 shared item)
Adds fdt_find_node_by_compatible() and fdt_find_prop_in_node() to the
minimal FDT reader -- the extension fdt.h's own header comment already
flagged as a known future need ("item 0.6 will need node-scoped reg
lookups"), now with real consumers: the Pi 5's UART/mailbox register
addresses (native boot, no ACPI) and the Milk-V Mars's real PLIC base
address (currently hardcoded to QEMU-virt's own value).
fdt_find_node_by_compatible() matches any entry in a node's
NUL-separated "compatible" list, first match in document order.
fdt_find_prop_in_node() scopes to that one node's own direct
properties only -- stops at the first child node or the node's own
end, per the DT spec's ordering guarantee that a node's properties
always precede its children. Same minimal, non-tree-building,
single-linear-scan-per-call style as the existing reader; no new
state, no allocation.
Compile-only verification -- no caller wired in yet, this is the
shared primitive both boards' own punch-list items will call once
built. Verified 3-arch boot to ok> (amd64/aarch64/riscv64, each in
the foreground).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019YcT3H2PQeyujrzjqS3Var
This commit is contained in:
Robert Allan James
co-authored by
Claude Sonnet 5
Claude Sonnet 5
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