Add uart printing support.

1 files changed, 134 insertions, 0 deletions

diff --git a/uart.c b/uart.c
new file mode 100644
index 0000000..d3fd848
--- /dev/null
+++ b/uart.c
@@ -0,0 +1,134 @@
+/*****************************************************************************
+
+       Copyright © 1995, 1996 Digital Equipment Corporation,
+                       Maynard, Massachusetts.
+
+                        All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and its 
+documentation for any purpose and without fee is hereby granted, provided  
+that the copyright notice and this permission notice appear in all copies  
+of software and supporting documentation, and that the name of Digital not  
+be used in advertising or publicity pertaining to distribution of the software 
+without specific, written prior permission. Digital grants this permission 
+provided that you prominently mark, as not part of the original, any 
+modifications made to this software or documentation.
+
+Digital Equipment Corporation disclaims all warranties and/or guarantees  
+with regard to this software, including all implied warranties of fitness for 
+a particular purpose and merchantability, and makes no representations 
+regarding the use of, or the results of the use of, the software and 
+documentation in terms of correctness, accuracy, reliability, currentness or
+otherwise; and you rely on the software, documentation and results solely at 
+your own risk. 
+
+******************************************************************************/
+
+/*
+ * david.rusling@reo.mts.dec.com
+ *
+ * Modified for QEMU PALcode by rth@twiddle.net.
+ */
+
+#include "io.h"
+#include "uart.h"
+
+#ifndef SERIAL_SPEED
+#define SERIAL_SPEED 9600
+#endif
+
+int
+uart_charav(int offset)
+{
+	return inb(com2Lsr + offset) & 1;
+}
+
+int
+uart_getchar(int offset)
+{
+	while (!uart_charav(offset))
+		continue;
+	return inb(com2Rbr + offset);
+}
+
+static void
+uart_putchar_raw(int offset, char c)
+{
+	while ((inb(com2Lsr + offset) & 0x20) == 0)
+		continue;
+	outb(c, com2Thr + offset);
+}
+
+void
+uart_putchar(int offset, char c)
+{
+	if (c == '\n')
+		uart_putchar_raw(offset, '\r');
+	uart_putchar_raw(offset, c);
+}
+
+void
+uart_puts(int offset, const char *s)
+{
+	while (*s != '\0')
+		uart_putchar(offset, *s++);
+}
+
+static void
+uart_init_line(int offset, int baud)
+{
+	int i;
+	int baudconst;
+
+	switch (baud) {
+	case 56000:
+		baudconst = 2;
+		break;
+	case 38400:
+		baudconst = 3;
+		break;
+	case 19200:
+		baudconst = 6;
+		break;
+	case 9600:
+		baudconst = 12;
+		break;
+	case 4800:
+		baudconst = 24;
+		break;
+	case 2400:
+		baudconst = 48;
+		break;
+	case 1200:
+		baudconst = 96;
+		break;
+	case 300:
+		baudconst = 384;
+		break;
+	case 150:
+		baudconst = 768;
+		break;
+	default:
+		baudconst = 12;
+		break;
+	}
+
+
+	outb(0x87, com2Lcr + offset);
+	outb(0, com2Dlm + offset);
+	outb(baudconst, com2Dll + offset);
+	outb(0x07, com2Lcr + offset);
+	outb(0x0F, com2Mcr + offset);
+
+	for (i = 10; i > 0; i--) {
+		if (inb(com2Lsr + offset) == 0)
+			break;
+		inb(com2Rbr + offset);
+	}
+}
+
+void uart_init(void)
+{
+	uart_init_line(COM1, SERIAL_SPEED);
+	uart_init_line(COM2, SERIAL_SPEED);
+}