feat: aarch64 port - Raspberry Pi 4/400 SD boot (SDHCI, ext2 root + first-boot grow), USB hubs, PCI INTx routing, SMP, DMA fences

kernel/src/ACPI/GsiRouting.cpp

@@ -0,0 +1,41 @@
+/*
+    * GsiRouting.cpp
+    * Platform interrupt lines for ACPI global system interrupts
+    * Copyright (c) 2026 Daniel Hammer
+*/
+
+#include "GsiRouting.hpp"
+#include <Arch/Interrupts.hpp>
+#include <CppLib/Spinlock.hpp>
+
+namespace Hal::GsiRouting {
+
+    static constexpr uint8_t FirstLine = 1;
+    static constexpr uint8_t LineCount = 24;
+
+    static uint32_t g_lineGsi[LineCount] = {};
+    static uint8_t g_nextLine = FirstLine;
+    static kcp::Mutex g_lock;
+
+    uint8_t LineForGsi(uint32_t gsi, bool levelTriggered, bool activeLow) {
+        if (Arch::PlatformLinesAreFixed()) return 0;
+
+        g_lock.Acquire();
+        for (uint8_t line = FirstLine; line < g_nextLine; line++) {
+            if (g_lineGsi[line] == gsi) {
+                g_lock.Release();
+                return line;
+            }
+        }
+
+        uint8_t line = 0;
+        if (g_nextLine < LineCount &&
+            Arch::AssignPlatformLine(g_nextLine, gsi, levelTriggered, activeLow)) {
+            line = g_nextLine++;
+            g_lineGsi[line] = gsi;
+        }
+        g_lock.Release();
+        return line;
+    }
+
+}