Merge pull request #12 from 0xKSor/feat/dtb

Feat/dtb

Kernel/.clangd

@@ -1,2 +1,3 @@
 CompileFlags:
   CompilationDatabase: ../.build/temp/Kernel
+  Add: [-std=c23]

Kernel/Include/Lib/Bytes.h

@@ -8,3 +8,7 @@ static inline UInt32 BytesSwap32(UInt32 value) {
 static inline UInt64 BytesSwap64(UInt64 value) {
     return __builtin_bswap64(value);
 }
+
+static inline UInt64 Merge32To64(UInt32 low, UInt32 high) {
+    return ((UInt64)high << 32) | low;
+}

Kernel/Include/Lib/String.h

@@ -15,4 +15,6 @@ Size StringGetLength(const ASCII* string);
 const ASCII* StringFindLastOccurrenceOfCharacter(const ASCII* string, ASCII separator);
 
 Int32 StringFormatVariadic(ASCII* string, Size size, const ASCII* format, va_list args);
-Int32 StringFormat(ASCII* destination, UInt64 size, const ASCII* format, ...);
+Int32 StringFormat(ASCII* destination, UInt64 size, const ASCII* format, ...);
+
+Boolean StringStartsWith(const ASCII* string, const ASCII* prefix);

Kernel/Include/Types.h

@@ -17,6 +17,7 @@ typedef unsigned long long UInt;
 
 typedef void* Pointer;
 typedef UInt Address;
+typedef UInt32 Address32;
 typedef UInt8* BytePointer;
 typedef UInt8* MemoryPointer;
 
@@ -30,3 +31,4 @@ typedef UInt64 Size;
 typedef char ASCII;
 
 typedef _Bool Boolean;
+#define loop while (1)

Kernel/Source/Arch/DTB.c

@@ -0,0 +1,63 @@
+#include <Arch/DTB.h>
+#include <OS/Panic.h>
+#include <OS/Log.h>
+#include <Lib/Bytes.h>
+#include <Lib/Align.h>
+#include <Lib/String.h>
+
+void DTBParse(Pointer dtb) {
+    FDTHeader* header = (FDTHeader*)dtb;
+    if (BytesSwap32(header->magic) != kFDTHeaderMagic) {
+        OSPanic("Invalid DTB magic");
+    }
+
+    UInt32 offStruct = BytesSwap32(header->offDtStruct);
+    UInt32 offStrings = BytesSwap32(header->offDtStrings);
+
+    BytePointer structs = (BytePointer)dtb + offStruct;
+    ASCII* strings = (ASCII*)dtb + offStrings;
+    ASCII* currentNode = "";
+
+    while (true) {
+        UInt32 token = BytesSwap32(*(UInt32*)structs);
+        structs += 4;
+
+        switch (token) {
+            case FDTTokenBeginNode: {
+                currentNode = (ASCII*)structs;
+
+                UInt32 nameLength = StringGetLength(currentNode);
+                structs += (nameLength + 1);
+                structs = (BytePointer)AlignUp64((Address)structs, 4);
+
+                break;
+            }
+            case FDTTokenProperty: {
+                UInt32 propertyLength = BytesSwap32(*(UInt32*)structs);
+                UInt32 nameOffset = BytesSwap32(*(UInt32*)(structs + 4));
+                structs += 8;
+
+                ASCII* propertyName = strings + nameOffset;
+                if (StringCompare(propertyName, "reg") == 0 && StringStartsWith(currentNode, "memory")) {
+                    UInt32* cells = (UInt32*)structs;
+                    
+                    UInt64 base = Merge32To64(BytesSwap32(cells[0]), BytesSwap32(cells[1]));
+                    UInt64 size = Merge32To64(BytesSwap32(cells[2]), BytesSwap32(cells[3]));
+
+                    OSLog("Memory: base=0x%x, size=0x%x\n", base, size);
+                }
+                structs += propertyLength;
+                structs = (BytePointer)AlignUp64((Address)structs, 4);
+
+                break;
+            }
+
+            case FDTTokenEndNode: break;
+            case FDTTokenNOP: continue;
+            case FDTTokenEnd: return;
+            default:
+                OSPanic("Invalid DTB token");
+        }
+    }
+
+}

Kernel/Source/Arch/Exceptions.c

@@ -3,6 +3,6 @@
 #include <IO/Serial.h>
 #include <OS/Panic.h>
 
-void ExceptionsHandler(ExceptionsContext* frame, ExceptionsType type) {
+void ExceptionsHandler(ExceptionsContext* frame, [[maybe_unused]]ExceptionsType type) {
     OSPanicException(frame);
 }

Kernel/Source/KernelMain.c

@@ -1,7 +1,8 @@
-#include <OS/Log.h>
 #include "../Common/bootinfo.h"
+#include <Arch/DTB.h>
+#include <OS/Log.h>
 
 void KernelMain(Bootinfo* bootinfo) {
-    OSLog("DTB located at 0x%x\n", bootinfo->dtb);
-    OSLog("Kernel located at 0x%x\n", bootinfo->kernelInfo.kernelAddress);
+    OSLog("Kernel started.\n");
+    DTBParse(bootinfo->dtb);
 }

Kernel/Source/Lib/String.c

@@ -176,4 +176,8 @@ Int32 StringFormat(ASCII* destination, UInt64 size, const ASCII* format, ...) {
     Int32 returnValue = StringFormatVariadic(destination, size, format, args);
     va_end(args);
     return returnValue;
+}
+
+Boolean StringStartsWith(const ASCII* string, const ASCII* prefix) {
+    return StringCompareWithLimit(string, prefix, StringGetLength(prefix)) == 0;
 }