serial and tty

build.zig

@@ -32,8 +32,10 @@ const kernel_src = &[_][]const u8{
     "kernel/cpu/pic.c",
     "kernel/drivers/drivers.c",
     "kernel/drivers/pci.c",
-    "kernel/io/io.c",
-    "kernel/io/panic.c",
+    "kernel/drivers/tty.c",
+    "kernel/drivers/uart.c",
+    "kernel/lib/fputc.c",
+    "kernel/lib/panic.c",
     "kernel/mboot/mboot.c",
     "kernel/mboot/mmap.c",
     "kernel/memory/memory.c",

kernel/drivers/drivers.c

@@ -1,7 +1,11 @@
 #include <comus/drivers.h>
+#include <comus/drivers/uart.h>
+#include <comus/drivers/tty.h>
 #include <comus/drivers/pci.h>
 
 void drivers_init(void)
 {
+	uart_init();
+	tty_init();
 	pci_init();
 }

kernel/drivers/pci.c

@@ -137,6 +137,8 @@ void pci_init(void)
 	printf("PCI DEVICES\n");
 	for (size_t i = 0; i < pci_table_next; i++) {
 		print_device(&pci_table[i]);
+		print_device(&pci_table[i]);
+		print_device(&pci_table[i]);
 	}
 	printf("\n");
 }

kernel/drivers/tty.c

@@ -0,0 +1,105 @@
+#include <lib.h>
+#include <comus/drivers/tty.h>
+#include <comus/asm.h>
+#include <comus/memory.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#define VGA_ADDR 0xB8000
+
+static const uint8_t width = 80;
+static const uint8_t height = 25;
+static volatile uint16_t *buffer = NULL;
+
+// position
+static uint32_t x, y;
+
+// color
+static uint8_t fg, bg;
+
+// blank color
+const uint16_t blank = (uint16_t) 0 | 0 << 12 | 15 << 8;
+
+static void term_clear_line(int line) {
+	if (line < 0 || line >= height)
+		return;
+	for (uint8_t x = 0; x < width; x++) {
+		const size_t index = line * width + x;
+		buffer[index] = blank;
+	}
+}
+
+static void term_clear(void) {
+    for (uint8_t y = 0; y < height; y++)
+        term_clear_line(y);
+}
+
+static void term_scroll(int lines) {
+	cli();
+	y -= lines;
+	if (!lines) return;
+	if (lines >= height || lines <= -height) {
+		term_clear();
+	} else if (lines > 0) {
+		memmovev(buffer, buffer + lines * width, 2 * (height - lines) * width);
+		term_clear_line(height - lines);
+	} else {
+		memmovev(buffer + lines * width, buffer + lines, (height + lines) * width);
+	}
+	sti();
+}
+
+void tty_init(void)
+{
+	buffer = mapaddr((void*)VGA_ADDR, width * height * sizeof(uint16_t));
+	x = 0;
+	y = 0;
+	fg = 15;
+	bg = 0;
+}
+
+void tty_out(char c)
+{
+	if (buffer == NULL)
+		return;
+
+	// handle special chars
+	switch (c) {
+	case '\n':
+		x = 0;
+		y++;
+		break;
+	case '\t':
+		x += 4;
+		break;
+	case '\v':
+	case '\f':
+		y++;
+		break;
+	case '\r':
+		x = 0;
+		break;
+	default: {
+		const size_t index = y * width + x;
+		buffer[index] = c | bg << 12 | fg << 8;
+		x++;
+	}
+	}
+
+	// wrap cursor if needed
+	if (x >= width) {
+		x = 0;
+		y++;
+	}
+	if (y >= height) {
+		term_scroll(y - (height - 1));
+		y = height - 1;
+	}
+
+	// set cursor position on screen
+	const uint16_t pos = y * width + x;
+	outb(0x3D4, 0x0F);
+	outb(0x3D5, (uint8_t) (pos & 0xFF));
+	outb(0x3D4, 0x0E);
+	outb(0x3D5, (uint8_t) ((pos >> 8) & 0xFF));
+}

kernel/drivers/uart.c

@@ -0,0 +1,43 @@
+#include <comus/drivers/uart.h>
+#include <comus/asm.h>
+
+#define PORT 0x3F8
+
+int uart_init(void) {
+	outb(PORT + 1, 0x00); // disable interrupts
+	outb(PORT + 3, 0x80); // enable DLAB (divisor latch access bit)
+	outb(PORT + 0, 0x03); // (lo) Set baud divisor to 3 38400 baud
+	outb(PORT + 1, 0x00); // (hi)
+	outb(PORT + 3, 0x03); // disable DLAB, set 8 bits per word, one stop bit, no parity
+	outb(PORT + 2, 0xC7); // enable and clear FIFOs, set to maximum threshold
+	outb(PORT + 4, 0x0B); // ???
+	outb(PORT + 4, 0x1E); // set in loopback mode for test
+	outb(PORT + 0, 0xAE); // test by sending 0xAE
+
+	uint8_t response = inb(PORT + 0);
+	if (response != 0xAE) {
+		// TODO: panic here?
+		return -1;
+	}
+
+	// disable loopback, enable IRQs
+	outb(PORT + 4, 0x0F);
+	return 0;
+}
+
+uint8_t uart_in(void) {
+	// wait for data to be available
+	while ((inb(PORT + 5) & 0x01) == 0);
+	return inb(PORT);
+}
+
+void uart_out(uint8_t ch) {
+	// wait for output to be free
+	while ((inb(PORT + 5) & 0x20) == 0);
+	outb(PORT, ch);
+}
+
+void uart_out_str(const char *str) {
+	while (*str)
+		uart_out(*str++);
+}

kernel/include/comus/drivers/tty.h

@@ -0,0 +1,27 @@
+/**
+ * @file tty.h
+ *
+ * @author Freya Murphy <freya@freyacat.org>
+ *
+ * Terminal output
+ */
+
+#ifndef TTY_H_
+#define TTY_H_
+
+/**
+ * Initalize the terminal
+ */
+void tty_init(void);
+
+/**
+ * Output a character to the terminal
+ */
+void tty_out(char c);
+
+/**
+ * Output a string to the terminal
+ */
+void tty_out_str(char *str);
+
+#endif /* tty.h */

kernel/include/comus/drivers/uart.h

@@ -0,0 +1,19 @@
+/**
+ * @file uart.h
+ *
+ * @author Freya Murphy <freya@freyacat.org>
+ *
+ * Serial interface
+ */
+
+#ifndef UART_H_
+#define UART_H_
+
+#include <stdint.h>
+
+int uart_init(void);
+uint8_t uart_in(void);
+void uart_out(uint8_t ch);
+void uart_out_str(const char *str);
+
+#endif /* uart.h */

kernel/io/io.c

@@ -1,19 +0,0 @@
-#include <lib.h>
-#include <stdio.h>
-#include <comus/asm.h>
-
-#define PORT 0x3F8
-static void serial_out(uint8_t ch)
-{
-	// wait for output to be free
-	while ((inb(PORT + 5) & 0x20) == 0)
-		;
-	outb(PORT, ch);
-}
-
-void fputc(FILE *stream, char c)
-{
-	(void)stream;
-
-	serial_out(c);
-}

kernel/lib/fputc.c

@@ -0,0 +1,11 @@
+#include <lib.h>
+#include <comus/drivers/tty.h>
+#include <comus/drivers/uart.h>
+
+void fputc(FILE *stream, char c)
+{
+	(void)stream; // TODO: manage stream
+	uart_out(c);
+	tty_out(c);
+}
+