From be0c9f82e37d64a266cf03035810cd1b74649e83 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Sat, 25 Aug 2018 19:14:28 +0100
Subject: [PATCH] sbcv2: More UART features

In particular set up the port properly rather than relying on ROMWBW. Also
turn on the interrupts.
---
 Kernel/platform-sbcv2/devtty.c | 63 +++++++++++++++++++++++++++++++---
 1 file changed, 59 insertions(+), 4 deletions(-)

diff --git a/Kernel/platform-sbcv2/devtty.c b/Kernel/platform-sbcv2/devtty.c
index 6ea0ef99..6ef03a7e 100644
--- a/Kernel/platform-sbcv2/devtty.c
+++ b/Kernel/platform-sbcv2/devtty.c
@@ -1,5 +1,10 @@
 /*
  *	We have a 16x50 UART at 0x68 and maybe a PropIO2 at A8
+ *
+ *	TODO:
+ *	- Hardware flow control
+ *	- Support for abuse of 16x50 as interrupt controller
+ *	- Support for timer hack
  */
 
 #include <kernel.h>
@@ -11,7 +16,15 @@
 
 __sfr __at 0x68 uart_tx;
 __sfr __at 0x68 uart_rx;
+__sfr __at 0x68 uart_ls;
+__sfr __at 0x69 uart_ier;
+__sfr __at 0x69 uart_ms;
+__sfr __at 0x6A uart_fcr;
+__sfr __at 0x6B uart_lcr;
+__sfr __at 0x6C uart_mcr;
 __sfr __at 0x6D uart_lsr;
+__sfr __at 0x6E uart_msr;
+__sfr __at 0x6F uart_scr;
 
 static char tbuf1[TTYSIZ];
 static char tbuf2[TTYSIZ];
@@ -30,7 +43,6 @@ struct s_queue ttyinq[NUM_DEV_TTY + 1] = {	/* ttyinq[0] is never used */
 /* Write to system console */
 void kputchar(char c)
 {
-	/* Need to make console dynamic FIXME */
 	if (c == '\n')
 		tty_putc(1, '\r');
 	tty_putc(1, c);
@@ -54,9 +66,50 @@ void tty_putc(uint8_t minor, unsigned char c)
 		prop_tty_write(c);
 }
 
+static uint16_t clocks[] = {
+	12,		/* Not a real rate */
+	2304,
+	1536,
+	1047,
+	857,
+	768,
+	384,
+	192,
+	96,
+	48,
+	24,
+	12,
+	6,
+	3,
+	2,
+	1
+};
+
 void tty_setup(uint8_t minor)
 {
-	minor;
+	uint8_t d;
+	uint16_t w;
+	struct termios *t = &ttydata[minor].termios;
+	if (ttymap[minor] == 1) {
+		/* 16x50. Can actually be configured */
+		d = 0x80;	/* DLAB */
+		d |= (t->c_cflag & CSIZE) >> 4;
+		if(t->c_cflag & CSTOPB)
+			d |= 0x04;
+		if (t->c_cflag & PARENB)
+			d |= 0x08;
+		if (!(t->c_cflag & PARODD))
+			d |= 0x10;
+		uart_lcr = d;
+		w = clocks[t->c_cflag & CBAUD];
+		uart_ls = w;
+		uart_ms = w >> 8;
+		uart_lcr = d & 0x7F;
+		/* FIXME: CTS/RTS support */
+		d = 0x00;	/* !DTR !RTS */
+		uart_lcr = d;
+		uart_ier = 0x0D;	/* We don't use tx ints */
+	}
 }
 
 void tty_sleeping(uint8_t minor)
@@ -66,7 +119,8 @@ void tty_sleeping(uint8_t minor)
 
 int tty_carrier(uint8_t minor)
 {
-        minor;
+        if (ttymap[minor] == 1)
+		return uart_msr & 0x80;
 	return 1;
 }
 
@@ -76,7 +130,8 @@ void tty_data_consumed(uint8_t minor)
 
 void tty_poll(void)
 {	
-	/* Should be IRQ driven for this */
+	/* Should be IRQ driven but we might not be so poll anyway if
+	   pending. IRQs are off here so this is safe */
 	if (uart_lsr & 0x01)
 		tty_inproc(ttymap[1], uart_rx);
 	prop_tty_poll(ttymap[2]);
-- 
2.34.1