WIP: Add serial driver

Makefile

@@ -76,7 +76,7 @@ obj_directories:
 
 # Run bootable ISO
 run: dist/panix.iso
-	$(QEMU) -drive format=raw,file=$< -soundhw pcspk -rtc clock=host -vga std
+	$(QEMU) -drive format=raw,file=$< -soundhw pcspk -rtc clock=host -vga std -serial mon:stdio
 
 # Install BIN file to local system
 install: dist/panix.bin

include/drivers/serial/Rs232.hpp

@@ -0,0 +1,79 @@
+/**
+ * @file Rs232.hpp
+ * @author Micah Switzer (mswitzer@cedarville.edu)
+ * @brief 
+ * @version 0.1
+ * @date 2019-09-30
+ * 
+ * @copyright Copyright (c) 2019
+ * 
+ */
+#ifndef PANIX_RS232_DRIVER
+#define PANIX_RS232_DRIVER
+
+#include <types.hpp>
+#include <cpu/port/Port.hpp>
+#include <cpu/interrupts/InterruptHandler.hpp>
+#include <cpu/interrupts/InterruptManager.hpp>
+#include <drivers/Driver.hpp>
+#include <drivers/DriverManager.hpp>
+#include <libc/string.hpp>
+#include <libc/kprint.hpp>
+
+#define COM1 0x3F8
+#define COM2 0x2F8
+#define COM3 0x3E8
+#define COM4 0x2E8
+
+#define COM1_IRQ 0x04
+#define COM3_IRQ 0x04
+#define COM2_IRQ 0x03
+#define COM4_IRQ 0x03
+
+#define DATA_REG 0
+#define INTERRUPT_ENABLE_REG 1
+#define INTERRUPT_IDENTIFICATION_REG 2
+#define LINE_CONTROL_REG 3
+#define MODEM_CONTROL_REG 4
+#define LINE_STATUS_REG 5
+#define MODEM_STATUS_REG 6
+#define SCRATCH_REG 7
+
+#define BUF_SIZE 75
+
+class Rs232 : public InterruptHandler, public Driver {
+    private:
+        char* lineBuffer[BUF_SIZE];
+        uint8_t lineIndex;
+        uint16_t portBase;
+
+        char readSerial();
+        int serialReceived();
+        int isTransmitEmpty();
+        void writeSerial(char a);
+
+    public:
+        Rs232(uint16_t portNum, InterruptManager* interruptManager);
+        ~Rs232();
+        void activate();
+        void deactivate();
+        void print(char* str);
+        /**
+         * @brief 
+         * 
+         * @param esp 
+         * @return uint32_t 
+         */
+        uint32_t handleInterrupt(uint32_t esp);
+        /**
+         * @brief Returns the short tag type of the driver. Used to identify
+         * the driver and its purpose. Used by the driver manager to get a
+         * specific driver type.
+         * 
+         * @return char* Short driver type tag
+         */
+        char* getDriverTypeTag();
+};
+
+#endif /* PANIX_RS232_DRIVER */
+

include/kernel/kernel.hpp

@@ -25,6 +25,7 @@
 #include <drivers/speaker/Speaker.hpp>
 #include <drivers/timer/Timer.hpp>
 #include <drivers/rtc/RTC.hpp>
+#include <drivers/serial/Rs232.hpp>
 // Graphical Interface
 #include <kernel/gui/Desktop.hpp>
 #include <kernel/gui/Window.hpp>

src/drivers/serial/Rs232.cpp

@@ -0,0 +1,79 @@
+/**
+ * @file Rs232.cpp
+ * @author Micah Switzer (mswitzer@cedarville.edu)
+ * @brief 
+ * @version 0.1
+ * @date 2019-09-30
+ * 
+ * @copyright Copyright (c) 2019
+ * 
+ */
+#include <drivers/serial/Rs232.hpp>
+
+Rs232::Rs232(uint16_t portNum, InterruptManager* interruptManager) :
+    InterruptHandler(interruptManager, 0x20 + (portNum == COM1 ? COM1_IRQ : COM2_IRQ)),
+    portBase(portNum),
+    lineIndex(0) {
+}
+
+Rs232::~Rs232() {
+// stubbed
+}
+
+char Rs232::readSerial() {
+    while (serialReceived() == 0);
+    return readByte(portBase + DATA_REG);
+}
+
+int Rs232::serialReceived() {
+    return readByte(portBase + LINE_STATUS_REG) & 1;
+}
+
+int Rs232::isTransmitEmpty() {
+    return readByte(portBase + LINE_STATUS_REG) & 0x20;
+}
+
+void Rs232::writeSerial(char a) {
+    while (isTransmitEmpty() == 0);
+    writeByte(portBase + DATA_REG, a);
+}
+
+void Rs232::activate() {
+    // disable interrupts
+    writeByte(portBase + INTERRUPT_ENABLE_REG, 0x00);
+    writeByte(portBase + LINE_CONTROL_REG, 0x80);
+    writeByte(portBase + DATA_REG, 0x03);
+    writeByte(portBase + INTERRUPT_ENABLE_REG, 0x00);
+    writeByte(portBase + LINE_CONTROL_REG, 0x03);
+    writeByte(portBase + INTERRUPT_IDENTIFICATION_REG, 0xC7);
+    writeByte(portBase + MODEM_CONTROL_REG, 0x0B);
+    writeByte(portBase + LINE_CONTROL_REG, 0x00);
+    // re-enable interrupts
+    writeByte(portBase + INTERRUPT_ENABLE_REG, 0x01);
+}
+
+void Rs232::deactivate() {
+// stubbed
+}
+
+void Rs232::print(char* str) {
+    int i = 0;
+    while (str[i] != 0) {
+        writeSerial(str[i]);
+        ++i;
+    }
+}
+
+uint32_t Rs232::handleInterrupt(uint32_t esp) {
+    //if (lineIndex == BUF_SIZE)
+    char str[2] = { readSerial(), '\0' };
+    if (str[0] == '\r') {
+        print("\n");
+    }
+    print(str);
+    return esp;
+}
+
+char* Rs232::getDriverTypeTag() {
+    return "RS232";
+}

src/kernel/kernel.cpp

@@ -82,6 +82,8 @@ extern "C" void kernelMain(const void* multiboot_structure, uint32_t multiboot_m
     // PCI Interface Driver
     PeripheralComponentInterconnectController PCIController;
     PCIController.SelectDrivers(&driverManager, &interruptManager);
+    Rs232 serial = Rs232(COM1, &interruptManager);
+    driverManager.addDriver(&serial);
 
     // If we put all of the code in startShellAsProcess here then it works.
     // But if we make the call to it here then it doesn't.
@@ -94,6 +96,8 @@ extern "C" void kernelMain(const void* multiboot_structure, uint32_t multiboot_m
     kprint("Stage 2 - Activating Drivers...\n");
     kprintSetColor(White, Black);
     driverManager.activateAll();
+
+    serial.print("I think it works?\n");
 
     /*********************************
      * STAGE 3 - ACTIVATE INTERRUPTS *