path: root/drivers/serial/68328serial.c

/* 68328serial.c: Serial port driver for 68328 microcontroller
 *
 * Copyright (C) 1995       David S. Miller    <davem@caip.rutgers.edu>
 * Copyright (C) 1998       Kenneth Albanowski <kjahds@kjahds.com>
 * Copyright (C) 1998, 1999 D. Jeff Dionne     <jeff@uclinux.org>
 * Copyright (C) 1999       Vladimir Gurevich  <vgurevic@cisco.com>
 * Copyright (C) 2002-2003  David McCullough   <davidm@snapgear.com>
 * Copyright (C) 2002       Greg Ungerer       <gerg@snapgear.com>
 *
 * VZ Support/Fixes             Evan Stawnyczy <e@lineo.ca>
 * Multiple UART support        Daniel Potts <danielp@cse.unsw.edu.au>
 * Power management support     Daniel Potts <danielp@cse.unsw.edu.au>
 * VZ Second Serial Port enable Phil Wilshire
 * 2.4/2.5 port                 David McCullough
 */

#include <asm/dbg.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/console.h>
#include <linux/reboot.h>
#include <linux/keyboard.h>
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/bitops.h>
#include <linux/delay.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/delay.h>
#include <asm/uaccess.h>

/* (es) */
/* note: perhaps we can murge these files, so that you can just
 * 	 define 1 of them, and they can sort that out for themselves
 */
#if defined(CONFIG_M68EZ328)
#include <asm/MC68EZ328.h>
#else
#if defined(CONFIG_M68VZ328)
#include <asm/MC68VZ328.h>
#else
#include <asm/MC68328.h>
#endif /* CONFIG_M68VZ328 */
#endif /* CONFIG_M68EZ328 */

#include "68328serial.h"

/* Turn off usage of real serial interrupt code, to "support" Copilot */
#ifdef CONFIG_XCOPILOT_BUGS
#undef USE_INTS
#else
#define USE_INTS
#endif

static struct m68k_serial m68k_soft[NR_PORTS];
struct m68k_serial *IRQ_ports[NR_IRQS];

static unsigned int uart_irqs[NR_PORTS] = UART_IRQ_DEFNS;

/* multiple ports are contiguous in memory */
m68328_uart *uart_addr = (m68328_uart *)USTCNT_ADDR;

struct tty_struct m68k_ttys;
struct m68k_serial *m68k_consinfo = 0;

#define M68K_CLOCK (16667000) /* FIXME: 16MHz is likely wrong */

#ifdef CONFIG_CONSOLE
extern wait_queue_head_t keypress_wait; 
#endif

struct tty_driver *serial_driver;

/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256

/* Debugging... DEBUG_INTR is bad to use when one of the zs
 * lines is your console ;(
 */
#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW

#define RS_ISR_PASS_LIMIT 256

static void change_speed(struct m68k_serial *info);

/*
 *	Setup for console. Argument comes from the boot command line.
 */

#if defined(CONFIG_M68EZ328ADS) || defined(CONFIG_ALMA_ANS) || defined(CONFIG_DRAGONIXVZ)
#define	CONSOLE_BAUD_RATE	115200
#define	DEFAULT_CBAUD		B115200
#else
	/* (es) */
	/* note: this is messy, but it works, again, perhaps defined somewhere else?*/
	#ifdef CONFIG_M68VZ328
	#define CONSOLE_BAUD_RATE	19200
	#define DEFAULT_CBAUD		B19200
	#endif
	/* (/es) */
#endif

#ifndef CONSOLE_BAUD_RATE
#define	CONSOLE_BAUD_RATE	9600
#define	DEFAULT_CBAUD		B9600
#endif


static int m68328_console_initted = 0;
static int m68328_console_baud    = CONSOLE_BAUD_RATE;
static int m68328_console_cbaud   = DEFAULT_CBAUD;


static inline int serial_paranoia_check(struct m68k_serial *info,
					char *name, const char *routine)
{
#ifdef SERIAL_PARANOIA_CHECK
	static const char *badmagic =
		"Warning: bad magic number for serial struct %s in %s\n";
	static const char *badinfo =
		"Warning: null m68k_serial for %s in %s\n";

	if (!info) {
		printk(badinfo, name, routine);
		return 1;
	}
	if (info->magic != SERIAL_MAGIC) {
		printk(badmagic, name, routine);
		return 1;
	}
#endif
	return 0;
}

/*
 * This is used to figure out the divisor speeds and the timeouts
 */
static int baud_table[] = {
	0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
	9600, 19200, 38400, 57600, 115200, 0 };

#define BAUD_TABLE_SIZE (sizeof(baud_table)/sizeof(baud_table[0]))

/* Sets or clears DTR/RTS on the requested line */
static inline void m68k_rtsdtr(struct m68k_serial *ss, int set)
{
	if (set) {
		/* set the RTS/CTS line */
	} else {
		/* clear it */
	}
	return;
}

/* Utility routines */
static inline int get_baud(struct m68k_serial *ss)
{
	unsigned long result = 115200;
	unsigned short int baud = uart_addr[ss->line].ubaud;
	if (GET_FIELD(baud, UBAUD_PRESCALER) == 0x38) result = 38400;
	result >>= GET_FIELD(baud, UBAUD_DIVIDE);

	return result;
}

/*
 * ------------------------------------------------------------
 * rs_stop() and rs_start()
 *
 * This routines are called before setting or resetting tty->stopped.
 * They enable or disable transmitter interrupts, as necessary.
 * ------------------------------------------------------------
 */
static void rs_stop(struct tty_struct *tty)
{
	struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
	m68328_uart *uart = &uart_addr[info->line];
	unsigned long flags;

	if (serial_paranoia_check(info, tty->name, "rs_stop"))
		return;
	
	local_irq_save(flags);
	uart->ustcnt &= ~USTCNT_TXEN;
	local_irq_restore(flags);
}

static void rs_put_char(char ch)
{
        int flags, loops = 0;

        local_irq_save(flags);

	while (!(UTX & UTX_TX_AVAIL) && (loops < 1000)) {
        	loops++;
        	udelay(5);
        }

	UTX_TXDATA = ch;
        udelay(5);
        local_irq_restore(flags);
}

static void rs_start(struct tty_struct *tty)
{
	struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
	m68328_uart *uart = &uart_addr[info->line];
	unsigned long flags;
	
	if (serial_paranoia_check(info, tty->name, "rs_start"))
		return;
	
	local_irq_save(flags);
	if (info->xmit_cnt && info->xmit_buf && !(uart->ustcnt & USTCNT_TXEN)) {
#ifdef USE_INTS
		uart->ustcnt |= USTCNT_TXEN | USTCNT_TX_INTR_MASK;
#else
		uart->ustcnt |= USTCNT_TXEN;
#endif
	}
	local_irq_restore(flags);
}

/* Drop into either the boot monitor or kadb upon receiving a break
 * from keyboard/console input.
 */
static void batten_down_hatches(void)
{
	/* Drop into the debugger */
}

static void status_handle(struct m68k_serial *info, unsigned short status)
{
#if 0
	if(status & DCD) {
		if((info->tty->termios->c_cflag & CRTSCTS) &&
		   ((info->curregs[3] & AUTO_ENAB)==0)) {
			info->curregs[3] |= AUTO_ENAB;
			info->pendregs[3] |= AUTO_ENAB;
			write_zsreg(info->m68k_channel, 3, info->curregs[3]);
		}
	} else {
		if((info->curregs[3] & AUTO_ENAB)) {
			info->curregs[3] &= ~AUTO_ENAB;
			info->pendregs[3] &= ~AUTO_ENAB;
			write_zsreg(info->m68k_channel, 3, info->curregs[3]);
		}
	}
#endif
	/* If this is console input and this is a
	 * 'break asserted' status change interrupt
	 * see if we can drop into the debugger
	 */
	if((status & URX_BREAK) && info->break_abort)
		batten_down_hatches();
	return;
}

static void receive_chars(struct m68k_serial *info, unsigned short rx)
{
	struct tty_struct *tty = info->tty;
	m68328_uart *uart = &uart_addr[info->line];
	unsigned char ch, flag;

	/*
	 * This do { } while() loop will get ALL chars out of Rx FIFO 
         */
#ifndef CONFIG_XCOPILOT_BUGS
	do {
#endif	
		ch = GET_FIELD(rx, URX_RXDATA);
	
		if(info->is_cons) {
			if(URX_BREAK & rx) { /* whee, break received */
				status_handle(info, rx);
				return;
#ifdef CONFIG_MAGIC_SYSRQ
			} else if (ch == 0x10) { /* ^P */
				show_state();
				show_free_areas();
				show_buffers();
/*				show_net_buffers(); */
				return;
			} else if (ch == 0x12) { /* ^R */
				emergency_restart();
				return;
#endif