Modularized

1 files changed, 33 insertions, 0 deletions

diff --git a/kernel/lib/mmu.c b/kernel/lib/mmu.c
new file mode 100644
index 0000000..e9dda7a
--- /dev/null
+++ b/kernel/lib/mmu.c
@@ -0,0 +1,33 @@
+#include <lib/mmu.h>
+
+#define CACHABLE 0x08
+#define BUFFERABLE 0x04
+#define NO_PERMISSIONS_REQUIRED 0b11 << 10
+#define MMU_TABLE_BASE 0x00004000
+
+void mmu_start(unsigned long base, unsigned long flags);
+
+void mmu_section(unsigned long virtual, unsigned long physical, unsigned long flags)
+{
+	unsigned long offset = virtual >> 20;
+	unsigned long* entry = (unsigned long*)(MMU_TABLE_BASE | (offset << 2));
+	unsigned long physval = (physical & 0xFFF00000) | (flags & 0x7FFC) | 0x00C02;
+	*entry = physval;
+}
+
+extern unsigned long __bss_end;
+void mmu_init(void)
+{
+	for (unsigned long addr =  0x00000000;; addr += 0x00100000) {
+		if (addr < (unsigned long)&__bss_end + 0x00100000) {
+			mmu_section(addr, addr, CACHABLE | BUFFERABLE);
+		} else {
+			mmu_section(addr, addr, NO_PERMISSIONS_REQUIRED);
+		}
+		if (addr == 0x02000000)
+			mmu_section(addr, addr, CACHABLE | BUFFERABLE | NO_PERMISSIONS_REQUIRED);
+		if (addr == 0xFFF00000)
+			break;
+	}
+	mmu_start(MMU_TABLE_BASE,0x00000001|0x1000|0x0004);
+}