Merge pull request #27 from pbrucla/serial_driver

Serial driver

Makefile

@@ -49,14 +49,14 @@ image: boot kernel
 	$(DD) if=/dev/zero of=$(BUILD_DIR)/os_image seek=1 obs=1024 count=0 conv=notrunc
 
 run: default
-	$(QEMU) -drive format=raw,file=$(BUILD_DIR)/os_image
+	$(QEMU) -drive format=raw,file=$(BUILD_DIR)/os_image -serial stdio
 
 gdb: default
 	# Need to have GEF installed for this to work
 	$(QEMU) -drive format=raw,file=$(BUILD_DIR)/os_image -s -S & gdb -ex "gef-remote --qemu-user localhost 1234" build/kernel.elf
 
 dockerun:
-	$(QEMU) -drive format=raw,file=$(BUILD_DIR)/os_image
+	$(QEMU) -drive format=raw,file=$(BUILD_DIR)/os_image -serial stdio
 
 check:
 	@grep -RE $$'\r' source/ && echo "Found carriage returns in source files. Please run 'make format' to fix them." && exit 1 || exit 0

source/kernel/idt.c

@@ -47,7 +47,7 @@ __attribute__((noinline)) static void actualirq1Handler(void)
 
         // send eoi to the master PIC
         // this is needed in the PIC remapping, don't question it
-        outbb(0x20, 0x20);
+        outb(0x20, 0x20);
         __asm__ volatile("cli");
     }
 }
@@ -78,28 +78,28 @@ void setup_pic(void)
     unsigned char mask2 = inb(0xa1);
 
     // send initialization command (0x11) to both PICs
-    // PIC will now wait for 4 outbb to their data port
-    outbb(0x20, 0x11);
+    // PIC will now wait for 4 outb to their data port
+    outb(0x20, 0x11);
     io_wait();
-    outbb(0xa0, 0x11);
+    outb(0xa0, 0x11);
     io_wait();
 
     // remap PIC1 to 0x20-0x27 and PIC2 to 0x28-0x30
-    outbb(0x21, 0x20);
+    outb(0x21, 0x20);
     io_wait();
-    outbb(0xa1, 0x28);
+    outb(0xa1, 0x28);
     io_wait();
 
     // tell PIC1 and PIC2 about each other
-    outbb(0x21, 1 << 2); // PIC2 is at IRQ2
+    outb(0x21, 1 << 2); // PIC2 is at IRQ2
     io_wait();
-    outbb(0xa1, 2); // PIC1 cascade identify (idk what that means)
+    outb(0xa1, 2); // PIC1 cascade identify (idk what that means)
     io_wait();
 
     // tell PICs they are in 32-bit mode
-    outbb(0x21, 1);
+    outb(0x21, 1);
     io_wait();
-    outbb(0xa1, 1);
+    outb(0xa1, 1);
     io_wait();
 
     // restore previous irq masks (0xb8 for PIC1 and 0x8e for PIC2)
@@ -111,9 +111,9 @@ void setup_pic(void)
     // (which will enable them in hw)
     mask1 = 0xff ^ (1 << 1 | 1 << 2);
     mask2 = 0xff;
-    outbb(0x21, mask1);
+    outb(0x21, mask1);
     io_wait();
-    outbb(0xa1, mask2);
+    outb(0xa1, mask2);
     io_wait();
 }
 

source/kernel/include/serial.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include "string.h"
+
+enum COM_PORT {
+    COM1 = 0x3F8,
+    COM2 = 0x2F8,
+    COM3 = 0x3E8,
+    COM4 = 0x2E8,
+    COM5 = 0x5F8,
+    COM6 = 0x4F8,
+    COM7 = 0x5E8,
+    COM8 = 0x4E8
+};
+
+/**
+ * Return 1 if init is succesful
+ * Return 0 otherwise
+ */
+int serial_driver_init();
+void write_serial(enum COM_PORT port, const char *s);
+
+/* TODO implement this */
+int read_serial(enum COM_PORT port, char *dest);

source/kernel/init.c

@@ -1,6 +1,11 @@
 #include "init.h"
+#include "serial.h"
 #include "terminal_driver.h"
 
-void init_drivers() { terminal_driver_init(); }
+void init_drivers()
+{
+    serial_driver_init();
+    terminal_driver_init();
+}
 
 void init_kernel_stack() {}

source/kernel/isr.c

@@ -53,10 +53,10 @@ void irq_handler(registers_t *frame)
     uint32_t irq_no = int_no - IRQ_OFFSET;
     if (irq_no >= 8) {
         // reset slave
-        outbb(0xA0, 0x20);
+        outb(0xA0, 0x20);
     }
     // reset master
-    outbb(0x20, 0x20);
+    outb(0x20, 0x20);
     if (interrupt_handlers[int_no] != 0) {
         isr_t handler = interrupt_handlers[int_no];
         handler(frame);

source/kernel/kernel.c

@@ -2,6 +2,7 @@
 #include "init.h"
 #include "io.h"
 #include "memory.h"
+#include "serial.h"
 #include "string.h"
 #include "terminal_driver.h"
 #include "timer.h"
@@ -16,6 +17,10 @@ void main()
     init_idt();
     asm volatile("int $0x3");
     asm volatile("int $0x4");
+
+    write_serial(COM1, "Hello From SecureOS!");
+    // printf(s.data);
+
     // init_paging();
     // string s;
     // s.data =

source/kernel/serial.c

@@ -0,0 +1,60 @@
+#include "serial.h"
+#include "io.h"
+
+static int init_serial_port(enum COM_PORT port);
+inline static int putc_serial(enum COM_PORT port, char c);
+
+int serial_driver_init()
+{
+    return init_serial_port(COM1);
+
+    /* TODO initialize all COM ports */
+}
+
+static int init_serial_port(enum COM_PORT port)
+{
+    outb(port + 1, 0x00); // Disable all interrupts
+    outb(port + 3, 0x80); // Enable DLAB (set baud rate divisor)
+    outb(port + 0, 0x03); // Set divisor to 3 (lo byte) 38400 baud
+    outb(port + 1, 0x00); //                  (hi byte)
+    outb(port + 3, 0x03); // 8 bits, no parity, one stop bit
+    outb(port + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
+    outb(port + 4, 0x0B); // IRQs enabled, RTS/DSR set
+    outb(port + 4, 0x1E); // Set to loopback mode for test byte
+    outb(port + 0, 0xAE); // Send test byte
+
+    // If test byte was not returned, serial is faulty
+    if (inb(port + 0) != 0xAE)
+      return 0;
+
+    // // Otherwise, serial is operational, therefore disable loopback mode
+    outb(port + 4, 0x0F);
+    return 1;
+}
+
+void write_serial(enum COM_PORT port, const char *s)
+{
+    for (size_t i = 0; s[i] != '\0'; ++i)
+        putc_serial(port, s[i]);
+}
+
+int read_serial(enum COM_PORT port, char *dest)
+{
+    return 0;
+}
+
+inline static int transmit_buffer_empty(enum COM_PORT port)
+{
+    /* Read from transmit buffer empty register */
+    return inb(port + 5) & 0x20;
+}
+
+inline static int putc_serial(enum COM_PORT port, char c)
+{
+    /* Wait until transmit buffer is empty */
+    while (!transmit_buffer_empty(port))
+        ;
+
+    /* Write character to output buffer */
+    outb(port + 0, c);
+}

source/kernel/terminal_driver.c

@@ -77,6 +77,7 @@ void terminal_put64(unsigned long long n)
             temp += '0';
         else
             temp += 'A' - 10;
+
         terminal_putchar(temp);
     }
 }
@@ -93,27 +94,27 @@ void terminal_enable_cursor()
 {
     uint8_t cursor_start = 0;
     uint8_t cursor_end = 15;
-    outb(0x0A, 0x3D4);
-    outb((inb(0x3D5) & 0xC0) | cursor_start, 0x3D5);
+    outb(0x3D4, 0x0A);
+    outb(0x3D5, (inb(0x3D5) & 0xC0) | cursor_start);
 
-    outb(0x0B, 0x3D4);
-    outb((inb(0x3D5) & 0xE0) | cursor_end, 0x3D5);
+    outb(0x3D4, 0x0B);
+    outb(0x3D5, (inb(0x3D5) & 0xE0) | cursor_end);
 }
 
 void terminal_disable_cursor()
 {
-    outb(0x0A, 0x3D4);
-    outb(0x20, 0x3D5);
+    outb(0x3D4, 0x0A);
+    outb(0x3D5, 0x20);
     return;
 }
 
 void terminal_update_cursor()
 {
     uint16_t pos = cursor_row * VGA_WIDTH + cursor_col;
-    outb(0x0F, 0x3D4);
-    outb((uint8_t)(pos & 0xFF), 0x3D5);
-    outb(0x0E, 0x3D4);
-    outb((uint8_t)((pos >> 8) & 0xFF), 0x3D5);
+    outb(0x3D4, 0x0F);
+    outb(0x3D5, (uint8_t)(pos & 0xFF));
+    outb(0x3D4, 0x0E);
+    outb(0x3D5, (uint8_t)((pos >> 8) & 0xFF));
 }
 
 void terminal_move_cursor(uint8_t row, uint8_t col)

source/libc/include/io.h

@@ -2,8 +2,7 @@
 #include "string.h"
 
 unsigned char inb(unsigned short port);
-void outb(unsigned char value, unsigned short port);
-void outbb(unsigned short port, unsigned char value);
+void outb(unsigned short port, unsigned char value);
 void io_wait();
 // printf attached to terminal for now
 int printf(const char *s, ...);

source/libc/io.c

@@ -9,12 +9,8 @@ unsigned char inb(unsigned short port)
     __asm__ volatile("inb %1, %0" : "=a"(value) : "Nd"(port));
     return value;
 }
-void outb(unsigned char value, unsigned short port)
-{
-    __asm__ volatile("outb %0, %1" : : "a"(value), "Nd"(port));
-}
 
-void outbb(unsigned short port, unsigned char value)
+void outb(unsigned short port, unsigned char value)
 {
     __asm__ volatile("outb %0, %1" : : "a"(value), "Nd"(port));
 }