From ae4265ea5d77b68757af39d73fe47df1a3563b42 Mon Sep 17 00:00:00 2001
From: Aqua-sama <aqua@iserlohn-fortress.net>
Date: Sun, 28 Feb 2021 22:39:25 +0200
Subject: Add keyboard driver

---
 src/idt.cc                  | 24 +++++++++++++++++++++---
 src/idt.h                   | 27 ++++++++++++++++++++-------
 src/idt/interruptgate.cc    | 10 ++++++++++
 src/idt/interrupthandler.cc | 14 ++++++++++++++
 src/kernel.cc               |  6 ++++++
 src/makefile                |  3 ++-
 6 files changed, 73 insertions(+), 11 deletions(-)
 create mode 100644 src/idt/interruptgate.cc
 create mode 100644 src/idt/interrupthandler.cc

(limited to 'src')

diff --git a/src/idt.cc b/src/idt.cc
index fefe53e..68ae260 100644
--- a/src/idt.cc
+++ b/src/idt.cc
@@ -4,7 +4,23 @@
 #include "ports.h"
 
 static_assert(sizeof(IDT::Pointer) == 6);
-static_assert(sizeof(IDT::Entry) == 8);  // size of IDT::Entry in protected mode is 64 bits
+
+static InterruptHandler* handlers[256] = {nullptr};
+
+bool IDT::install(uint8_t irq, InterruptHandler* h) {
+  if (h != nullptr && handlers[irq] == nullptr) {
+    handlers[irq] = h;
+    return true;
+  }
+  return false;
+}
+bool IDT::uninstall(uint8_t irq, InterruptHandler* h) {
+  if (handlers[irq] == h) {
+    handlers[irq] = nullptr;
+    return true;
+  }
+  return false;
+}
 
 /* reinitialize the PIC controllers, giving them specified vector offsets
    rather than 8h and 70h, as configured by default */
@@ -22,7 +38,10 @@ static_assert(sizeof(IDT::Entry) == 8);  // size of IDT::Entry in protected mode
 #define ICW4_SFNM 0x10       /* Special fully nested (not) */
 
 extern "C" uint32_t handle_interrupt(uint8_t irq, uint32_t esp) {
-  printk("interrupt ", uhex{irq}, '\n');
+  if (handlers[irq] != nullptr) {
+    handlers[irq]->trigger();
+  }
+
   pic1_t pic1;
   pic1.write(0x20);
   if (irq > 7) {
@@ -91,7 +110,6 @@ IDT::IDT(const uint16_t selector) {
 
   Pointer ptr{.limit = sizeof(table), .base = reinterpret_cast<uint32_t>(table)};
   asm volatile("lidt %0" : : "m"(ptr));
-  asm volatile("sti");
 
   printk("IDT installed at ", uhex{ptr.base}, '\n');
 }
diff --git a/src/idt.h b/src/idt.h
index bc71f05..3a9848f 100644
--- a/src/idt.h
+++ b/src/idt.h
@@ -2,7 +2,21 @@
 
 #include <types.h>
 
+class InterruptHandler {
+private:
+  const uint8_t m_irq;
+
+protected:
+  InterruptHandler(uint8_t irq);
+  ~InterruptHandler();
+
+public:
+  virtual void trigger();
+};
+
 class IDT {
+  friend class InterruptHandler;
+
 public:
   struct Pointer {
     uint16_t limit;
@@ -19,24 +33,23 @@ public:
   class Entry {
   public:
     constexpr Entry() = default;
-    Entry(void (*handler)(), uint16_t select, InterruptType t) {
-      offset_0_15 = reinterpret_cast<uint32_t>(handler) & 0xffff;
-      offset_16_31 = (reinterpret_cast<uint32_t>(handler) >> 16) & 0xffff;
-      selector = select;
-      type = t;
-    }
+    Entry(void (*handler)(), uint16_t select, InterruptType t);
 
   private:
     uint16_t offset_0_15 = 0;            //  0-15 offset in the segment
     uint16_t selector = 0;               // 16-31 selector of the code segment
     [[maybe_unused]] uint8_t null = 0;   // 32-39 unused in protected mode
     InterruptType type = Null;           // 40-43 type
-    uint16_t offset_16_31 = 0;             // 48-63 offset high
+    uint16_t offset_16_31 = 0;           // 48-63 offset high
   } __attribute__((packed));
 
   IDT(const uint16_t selector);
+  void enable() { asm volatile("sti"); }
 
 private:
   Entry table[256];
+
+  static bool install(uint8_t, InterruptHandler*);
+  static bool uninstall(uint8_t, InterruptHandler*);
 };
 
diff --git a/src/idt/interruptgate.cc b/src/idt/interruptgate.cc
new file mode 100644
index 0000000..0dbcce2
--- /dev/null
+++ b/src/idt/interruptgate.cc
@@ -0,0 +1,10 @@
+#include "../idt.h"
+
+static_assert(sizeof(IDT::Entry) == 8);  // size of IDT::Entry in protected mode is 64 bits
+
+IDT::Entry::Entry(void (*handler)(), uint16_t select, IDT::InterruptType t) {
+  offset_0_15 = reinterpret_cast<uint32_t>(handler) & 0xffff;
+  offset_16_31 = (reinterpret_cast<uint32_t>(handler) >> 16) & 0xffff;
+  selector = select;
+  type = t;
+}
diff --git a/src/idt/interrupthandler.cc b/src/idt/interrupthandler.cc
new file mode 100644
index 0000000..7af830b
--- /dev/null
+++ b/src/idt/interrupthandler.cc
@@ -0,0 +1,14 @@
+#include <stdlib.h>
+#include "../idt.h"
+
+InterruptHandler::InterruptHandler(uint8_t irq) : m_irq(irq) {
+  IDT::install(m_irq, this);
+}
+
+InterruptHandler::~InterruptHandler() {
+  IDT::uninstall(m_irq, this);
+}
+
+void InterruptHandler::trigger() {
+  printk("Unhandled interrupt ", uhex{m_irq}, '\n');
+}
diff --git a/src/kernel.cc b/src/kernel.cc
index 6bfb021..ff8e6bd 100644
--- a/src/kernel.cc
+++ b/src/kernel.cc
@@ -15,6 +15,8 @@
 #include "idt.h"
 #include "serial.h"
 
+#include "keyboard.h"
+
 #include "hardware.h"
 
 typedef void (*constructor)();
@@ -48,6 +50,10 @@ void kernel_main([[maybe_unused]] uint32_t mb_magic, [[maybe_unused]] uint32_t m
   GDT gdt;
   IDT idt{gdt.codeDescriptor()};
 
+  Keyboard kb;
+
+  idt.enable();
+
   while (true) asm volatile("hlt");
 }
 }  // extern "C"
diff --git a/src/makefile b/src/makefile
index 8b21640..dda24af 100644
--- a/src/makefile
+++ b/src/makefile
@@ -7,7 +7,8 @@ CXX_OBJ += src/kernel.o \
 	   src/memory.o \
 	   src/gdt.o \
 	   src/gdt/segmentdescriptor.o \
-	   src/idt.o
+	   src/idt.o \
+	   src/idt/interruptgate.o src/idt/interrupthandler.o
 
 src/cpu/irq.h: $(OBJ_DIR)/src/cpu/exceptions.o $(OBJ_DIR)/src/cpu/interrupts.o
 	@echo "  GEN $@"
-- 
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