Commit Graph
3 Commits
Author SHA1 Message Date
Robert Allan JamesandClaude Sonnet 5 67e3fb7459 rpi5_native_boot.c: Pi 5 DTB->BootInfo constructor (FABRIC-3.md §IV.3 item 2)
Build / build-amd64-iso (push) Waiting to run
Build / build-aarch64-iso (push) Waiting to run
Build / build-riscv64-img (push) Waiting to run
rpi5_native_boot() populates the existing BootInfo struct from the
devicetree instead of UEFI protocols, then calls the existing, unmodified
kernel_main() -- the crux of why most of M1-M9 stays shared between the
UEFI and native boot paths. native_rpi5_entry.S now tail-calls into it
instead of halting.

memory_map is built from /memory's own reg, honoring the *root* node's
#address-cells/#size-cells (confirmed against bcm2712.dtsi's actual root
node -- <2>/<2> -- not assumed; a wrong cell width here would compile and
boot clean in QEMU while silently corrupting the real memory map on real
silicon). Required a new fdt_find_node_by_device_type() since /memory is
identified by device_type = "memory" per DT spec, not compatible.

args comes from /chosen's bootargs fed into the existing
cmdline_parse_ascii() (confirmed pure C99 with no UEFI coupling before
reusing it). framebuffer comes from the already-built
rpi5_mailbox_get_framebuffer() at a fixed 1920x1080x32 default -- no EDID
query exists in this codebase, flagged rather than guessed past.

Deliberately scoped out, not silently skipped: /reserved-memory is not
parsed. Carving reserved sub-ranges out of /memory's span needs
interval-splitting logic that would be written blind against hardware not
yet in hand -- exactly the kind of code that hides a bug until real
silicon. pmm.c's Pass 3 only ever clears pages this file lists as
EfiConventionalMemory, so the gap is "less usable RAM than optimal," never
"reserved RAM wrongly marked free." Left as its own future item.

Also fixes a real link failure this work surfaced: boot/cmdline.c was only
in LOADER_SRCS_BASE (the .efi target), not KERNEL_SRCS_BASE (the separate
.elf target arch/aarch64/*.c also wildcards into) -- added it there too.

Compile-only-verified; nothing in the existing UEFI/QEMU path calls
rpi5_native_boot(), so this cannot be exercised until real hardware.
Verified 3-arch boot to ok>/zuse)ok>.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019YcT3H2PQeyujrzjqS3Var
2026-09-04 14:42:32 -04:00
Robert Allan JamesandClaude Sonnet 5 5e46f18fd9 fdt.c: node-scoped lookup extension (FABRIC-3.md SSIV.3/SSV.3 shared item)
Build / build-amd64-iso (push) Waiting to run
Build / build-aarch64-iso (push) Waiting to run
Build / build-riscv64-img (push) Waiting to run
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
2026-09-04 13:05:42 -04:00
Robert Allan James accd79fc70 riscv64: integrate minimal flattened devicetree reader and switch timer to time CSR
Punch list §25 item 0.3 NOT complete.

- Added `starkernel/fdt.h` and `fdt.c` for minimal read-only devicetree parsing: sufficient for boot-time lookups such as `timebase-frequency`.
- Bootloader now captures the devicetree blob (DTB) from `EFI_DTB_TABLE_GUID` into `BootInfo::dtb`.
- RISC-V timer subsystem now uses the `time` CSR as the primary timestamp source, abandoning the hardcoded `cycle` frequency assumption.
- Timer rate is read from `timebase-frequency` in the DTB when accessible; otherwise, a fallback value is used with a RELATIVE trust level.
- Integrated the SBI TIME extension for one-shot timer deadlines, ensuring re-arming occurs after each tick to avoid missing heartbeats.

Verified: riscv64 builds clean, boots to the ok> prompt with no regression; `riscv64/timer.c` reports accurate frequencies on QEMU's default firmware.
Signed-off-by: Robert Allan James <robert.allan.james@gmail.com>
2026-08-03 13:10:17 -04:00