From 3a01573350296cc12a45786ddc4627beb90f39f1 Mon Sep 17 00:00:00 2001
From: Andrew Kaster <akaster@serenityos.org>
Date: Fri, 17 Feb 2023 10:35:13 -0700
Subject: [PATCH] =?UTF-8?q?Revert=20"Kernel:=20Migrate=20=E2=80=98main=20i?=
 =?UTF-8?q?d=20register=CA=BC=20access=20in=20Aarch64=20MMIO"?=
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This patch needed more review than it got.

This reverts commit a6526cd90c73534de340136b856b519a09c45f26.
---
 Kernel/Arch/aarch64/CPUID.h      | 20 --------------------
 Kernel/Arch/aarch64/RPi/MMIO.cpp |  6 +++---
 2 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/Kernel/Arch/aarch64/CPUID.h b/Kernel/Arch/aarch64/CPUID.h
index 637e31429f..bb134ef45c 100644
--- a/Kernel/Arch/aarch64/CPUID.h
+++ b/Kernel/Arch/aarch64/CPUID.h
@@ -272,26 +272,6 @@ AK_MAKE_ARBITRARY_SIZED_ENUM(CPUFeature, u256,
 
     __End = CPUFeature(1u) << 255u); // SENTINEL VALUE
 
-enum class ArmLimited { // 0x41
-    Cortex_A34 = 0xd02,
-    Cortex_A53 = 0xd03, // Raspberry Pi 2 v1.2 / Raspberry Pi 3
-    Cortex_A35 = 0xd04,
-    Cortex_A55 = 0xd05,
-    Cortex_A65 = 0xd06,
-    Cortex_A57 = 0xd07,
-    Cortex_A72 = 0xd08, // Raspberry Pi 4
-    Cortex_A73 = 0xd09,
-    Cortex_A75 = 0xd0a,
-    Cortex_A76 = 0xd0b,
-    Neoverse_N1 = 0xd0c,
-    Cortex_A77 = 0xd0d,
-    Cortex_A78 = 0xd41,
-    Cortex_A65AE = 0xd43,
-    Cortex_X1 = 0xd44,
-    Cortex_A78C = 0xd4b,
-    Cortex_X1C = 0xd4c,
-};
-
 CPUFeature::Type detect_cpu_features();
 StringView cpu_feature_to_name(CPUFeature::Type const&);
 StringView cpu_feature_to_description(CPUFeature::Type const&);
diff --git a/Kernel/Arch/aarch64/RPi/MMIO.cpp b/Kernel/Arch/aarch64/RPi/MMIO.cpp
index b10771de66..031ed3bdfd 100644
--- a/Kernel/Arch/aarch64/RPi/MMIO.cpp
+++ b/Kernel/Arch/aarch64/RPi/MMIO.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <Kernel/Arch/aarch64/CPUID.h>
+#include <Kernel/Arch/aarch64/MainIdRegister.h>
 #include <Kernel/Arch/aarch64/RPi/MMIO.h>
 
 namespace Kernel::RPi {
@@ -12,8 +12,8 @@ namespace Kernel::RPi {
 MMIO::MMIO()
     : m_base_address(0xFE00'0000)
 {
-    auto main_id_register = Aarch64::MIDR_EL1::read();
-    if (static_cast<ArmLimited>(main_id_register.PartNum) <= ArmLimited::Cortex_A53) // Raspberry Pi 3
+    MainIdRegister id;
+    if (id.part_num() <= MainIdRegister::RaspberryPi3)
         m_base_address = PhysicalAddress(0x3F00'0000);
 }