feat: implement FDT-based memory discovery and add comprehensive debug logging to exec syscalls

1 files changed, 45 insertions, 0 deletions

diff --git a/include/kernel/fdt.h b/include/kernel/fdt.h
new file mode 100644
index 0000000..89cbae6
--- /dev/null
+++ b/include/kernel/fdt.h
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 Richard Qin
+ * LumeOS - FDT Device Discovery
+ */
+
+#pragma once
+#include "common/types.h"
+
+// Single device descriptor (populated from FDT)
+struct FdtDevice {
+    uint64 base_addr;    // MMIO base address
+    uint64 size;         // MMIO region size
+    uint32 irq;          // Interrupt number (0 = none)
+};
+
+// Device registry — populated by fdt_parse(), consumed by drivers
+struct DeviceRegistry {
+    // Memory
+    uint64 mem_base;
+    uint64 mem_size;
+
+    // Core platform devices
+    FdtDevice uart;
+    FdtDevice plic;
+    FdtDevice clint;
+
+    // VirtIO devices (multiple possible)
+    static constexpr int MAX_VIRTIO = 8;
+    FdtDevice virtio[MAX_VIRTIO];
+    int virtio_count;
+
+    // MMIO ranges for kvminit() to map
+    static constexpr int MAX_MMIO = 16;
+    struct MmioRegion {
+        uint64 base;
+        uint64 size;
+    } mmio_regions[MAX_MMIO];
+    int mmio_count;
+};
+
+extern DeviceRegistry g_devices;
+
+// Parse FDT and populate g_devices
+void fdt_parse(uint64 dtb);