kernel: refactor aarch64 boot code

Signed-off-by: EnderIce2 <enderice2@protonmail.com>

Kernel/arch/aarch64/bootstrap/raspi/init.cpp

@@ -0,0 +1,44 @@
+/*
+	This file is part of Fennix Kernel.
+
+	Fennix Kernel is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix Kernel is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <types.h>
+#include <cpu.hpp>
+
+#include "../../../../kernel.h"
+
+using namespace CPU::aarch64;
+
+extern "C" __attribute__((section(".bootstrap.text"))) void _aarch64_start(uint64_t dtb_ptr32, uint64_t x1, uint64_t x2, uint64_t x3)
+{
+	MIDR_EL1 reg;
+	asmv("mrs %x0, midr_el1" : "=r"(reg.raw));
+
+	switch (reg.PartNum)
+	{
+	case 0xB76: /* Raspberry Pi 1 */
+	case 0xC07: /* Raspberry Pi 2 */
+	default:	/* Unknown */
+		CPU::Stop();
+	case 0xD03: /* Raspberry Pi 3 */
+		break;
+	case 0xD08: /* Raspberry Pi 4 */
+		break;
+	}
+
+	BootInfo *info = nullptr;
+	Entry(info);
+}