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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;

/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL    1
 
/* 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 /* CONFIG_MAGIC_SYSRQ */
                  }
                  /* It is a 'keyboard interrupt' ;-) */
#ifdef CONFIG_CONSOLE
                  wake_up(&keypress_wait);
#endif                  
            }

            if(!tty)
                  goto clear_and_exit;
            
            flag = TTY_NORMAL;

            if(rx & URX_PARITY_ERROR) {
                  flag = TTY_PARITY;
                  status_handle(info, rx);
            } else if(rx & URX_OVRUN) {
                  flag = TTY_OVERRUN;
                  status_handle(info, rx);
            } else if(rx & URX_FRAME_ERROR) {
                  flag = TTY_FRAME;
                  status_handle(info, rx);
            }
            tty_insert_flip_char(tty, ch, flag);
#ifndef CONFIG_XCOPILOT_BUGS
      } while((rx = uart->urx.w) & URX_DATA_READY);
#endif

      tty_schedule_flip(tty);

clear_and_exit:
      return;
}

static void transmit_chars(struct m68k_serial *info)
{
      m68328_uart *uart = &uart_addr[info->line];

      if (info->x_char) {
            /* Send next char */
            uart->utx.b.txdata = info->x_char;
            info->x_char = 0;
            goto clear_and_return;
      }

      if((info->xmit_cnt <= 0) || info->tty->stopped) {
            /* That's peculiar... TX ints off */
            uart->ustcnt &= ~USTCNT_TX_INTR_MASK;
            goto clear_and_return;
      }

      /* Send char */
      uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
      info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
      info->xmit_cnt--;

      if (info->xmit_cnt < WAKEUP_CHARS)
            schedule_work(&info->tqueue);

      if(info->xmit_cnt <= 0) {
            /* All done for now... TX ints off */
            uart->ustcnt &= ~USTCNT_TX_INTR_MASK;
            goto clear_and_return;
      }

clear_and_return:
      /* Clear interrupt (should be auto)*/
      return;
}

/*
 * This is the serial driver's generic interrupt routine
 */
irqreturn_t rs_interrupt(int irq, void *dev_id)
{
      struct m68k_serial * info;
      m68328_uart *uart;
      unsigned short rx;
      unsigned short tx;

      info = IRQ_ports[irq];
      if(!info)
          return IRQ_NONE;

      uart = &uart_addr[info->line];
      rx = uart->urx.w;

#ifdef USE_INTS
      tx = uart->utx.w;

      if (rx & URX_DATA_READY) receive_chars(info, rx);
      if (tx & UTX_TX_AVAIL)   transmit_chars(info);
#else
      receive_chars(info, rx);            
#endif
      return IRQ_HANDLED;
}

static void do_softint(struct work_struct *work)
{
      struct m68k_serial      *info = container_of(work, struct m68k_serial, tqueue);
      struct tty_struct *tty;
      
      tty = info->tty;
      if (!tty)
            return;
#if 0
      if (clear_bit(RS_EVENT_WRITE_WAKEUP, &info->event)) {
            tty_wakeup(tty);
      }
#endif   
}

/*
 * This routine is called from the scheduler tqueue when the interrupt
 * routine has signalled that a hangup has occurred.  The path of
 * hangup processing is:
 *
 *    serial interrupt routine -> (scheduler tqueue) ->
 *    do_serial_hangup() -> tty->hangup() -> rs_hangup()
 * 
 */
static void do_serial_hangup(struct work_struct *work)
{
      struct m68k_serial      *info = container_of(work, struct m68k_serial, tqueue_hangup);
      struct tty_struct *tty;
      
      tty = info->tty;
      if (!tty)
            return;

      tty_hangup(tty);
}


static int startup(struct m68k_serial * info)
{
      m68328_uart *uart = &uart_addr[info->line];
      unsigned long flags;
      
      if (info->flags & S_INITIALIZED)
            return 0;

      if (!info->xmit_buf) {
            info->xmit_buf = (unsigned char *) __get_free_page(GFP_KERNEL);
            if (!info->xmit_buf)
                  return -ENOMEM;
      }

      local_irq_save(flags);

      /*
       * Clear the FIFO buffers and disable them
       * (they will be reenabled in change_speed())
       */

      uart->ustcnt = USTCNT_UEN;
      info->xmit_fifo_size = 1;
      uart->ustcnt = USTCNT_UEN | USTCNT_RXEN | USTCNT_TXEN;
      (void)uart->urx.w;

      /*
       * Finally, enable sequencing and interrupts
       */
#ifdef USE_INTS
      uart->ustcnt = USTCNT_UEN | USTCNT_RXEN | 
                 USTCNT_RX_INTR_MASK | USTCNT_TX_INTR_MASK;
#else
      uart->ustcnt = USTCNT_UEN | USTCNT_RXEN | USTCNT_RX_INTR_MASK;
#endif

      if (info->tty)
            clear_bit(TTY_IO_ERROR, &info->tty->flags);
      info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;

      /*
       * and set the speed of the serial port
       */

      change_speed(info);

      info->flags |= S_INITIALIZED;
      local_irq_restore(flags);
      return 0;
}

/*
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 */
static void shutdown(struct m68k_serial * info)
{
      m68328_uart *uart = &uart_addr[info->line];
      unsigned long     flags;

      uart->ustcnt = 0; /* All off! */
      if (!(info->flags & S_INITIALIZED))
            return;

      local_irq_save(flags);
      
      if (info->xmit_buf) {
            free_page((unsigned long) info->xmit_buf);
            info->xmit_buf = 0;
      }

      if (info->tty)
            set_bit(TTY_IO_ERROR, &info->tty->flags);
      
      info->flags &= ~S_INITIALIZED;
      local_irq_restore(flags);
}

struct {
      int divisor, prescale;
}
#ifndef CONFIG_M68VZ328
 hw_baud_table[18] = {
      {0,0}, /* 0 */
      {0,0}, /* 50 */
      {0,0}, /* 75 */
      {0,0}, /* 110 */
      {0,0}, /* 134 */
      {0,0}, /* 150 */
      {0,0}, /* 200 */
      {7,0x26}, /* 300 */
      {6,0x26}, /* 600 */
      {5,0x26}, /* 1200 */
      {0,0}, /* 1800 */
      {4,0x26}, /* 2400 */
      {3,0x26}, /* 4800 */
      {2,0x26}, /* 9600 */
      {1,0x26}, /* 19200 */
      {0,0x26}, /* 38400 */
      {1,0x38}, /* 57600 */
      {0,0x38}, /* 115200 */
};
#else
 hw_baud_table[18] = {
                 {0,0}, /* 0 */
                 {0,0}, /* 50 */
                 {0,0}, /* 75 */
                 {0,0}, /* 110 */
                 {0,0}, /* 134 */
                 {0,0}, /* 150 */
                 {0,0}, /* 200 */
                 {0,0}, /* 300 */
                 {7,0x26}, /* 600 */
                 {6,0x26}, /* 1200 */
                 {0,0}, /* 1800 */
                 {5,0x26}, /* 2400 */
                 {4,0x26}, /* 4800 */
                 {3,0x26}, /* 9600 */
                 {2,0x26}, /* 19200 */
                 {1,0x26}, /* 38400 */
                 {0,0x26}, /* 57600 */
                 {1,0x38}, /* 115200 */
}; 
#endif
/* rate = 1036800 / ((65 - prescale) * (1<<divider)) */

/*
 * This routine is called to set the UART divisor registers to match
 * the specified baud rate for a serial port.
 */
static void change_speed(struct m68k_serial *info)
{
      m68328_uart *uart = &uart_addr[info->line];
      unsigned short port;
      unsigned short ustcnt;
      unsigned cflag;
      int   i;

      if (!info->tty || !info->tty->termios)
            return;
      cflag = info->tty->termios->c_cflag;
      if (!(port = info->port))
            return;

      ustcnt = uart->ustcnt;
      uart->ustcnt = ustcnt & ~USTCNT_TXEN;

      i = cflag & CBAUD;
        if (i & CBAUDEX) {
                i = (i & ~CBAUDEX) + B38400;
        }

      info->baud = baud_table[i];
      uart->ubaud = PUT_FIELD(UBAUD_DIVIDE,    hw_baud_table[i].divisor) | 
            PUT_FIELD(UBAUD_PRESCALER, hw_baud_table[i].prescale);

      ustcnt &= ~(USTCNT_PARITYEN | USTCNT_ODD_EVEN | USTCNT_STOP | USTCNT_8_7);
      
      if ((cflag & CSIZE) == CS8)
            ustcnt |= USTCNT_8_7;
            
      if (cflag & CSTOPB)
            ustcnt |= USTCNT_STOP;

      if (cflag & PARENB)
            ustcnt |= USTCNT_PARITYEN;
      if (cflag & PARODD)
            ustcnt |= USTCNT_ODD_EVEN;
      
#ifdef CONFIG_SERIAL_68328_RTS_CTS
      if (cflag & CRTSCTS) {
            uart->utx.w &= ~ UTX_NOCTS;
      } else {
            uart->utx.w |= UTX_NOCTS;
      }
#endif

      ustcnt |= USTCNT_TXEN;
      
      uart->ustcnt = ustcnt;
      return;
}

/*
 * Fair output driver allows a process to speak.
 */
static void rs_fair_output(void)
{
      int left;         /* Output no more than that */
      unsigned long flags;
      struct m68k_serial *info = &m68k_soft[0];
      char c;

      if (info == 0) return;
      if (info->xmit_buf == 0) return;

      local_irq_save(flags);
      left = info->xmit_cnt;
      while (left != 0) {
            c = info->xmit_buf[info->xmit_tail];
            info->xmit_tail = (info->xmit_tail+1) & (SERIAL_XMIT_SIZE-1);
            info->xmit_cnt--;
            local_irq_restore(flags);

            rs_put_char(c);

            local_irq_save(flags);
            left = min(info->xmit_cnt, left-1);
      }

      /* Last character is being transmitted now (hopefully). */
      udelay(5);

      local_irq_restore(flags);
      return;
}

/*
 * m68k_console_print is registered for printk.
 */
void console_print_68328(const char *p)
{
      char c;
      
      while((c=*(p++)) != 0) {
            if(c == '\n')
                  rs_put_char('\r');
            rs_put_char(c);
      }

      /* Comment this if you want to have a strict interrupt-driven output */
      rs_fair_output();

      return;
}

static void rs_set_ldisc(struct tty_struct *tty)
{
      struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;

      if (serial_paranoia_check(info, tty->name, "rs_set_ldisc"))
            return;

      info->is_cons = (tty->termios->c_line == N_TTY);
      
      printk("ttyS%d console mode %s\n", info->line, info->is_cons ? "on" : "off");
}

static void rs_flush_chars(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_flush_chars"))
            return;
#ifndef USE_INTS
      for(;;) {
#endif

      /* Enable transmitter */
      local_irq_save(flags);

      if (info->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
                  !info->xmit_buf) {
            local_irq_restore(flags);
            return;
      }

#ifdef USE_INTS
      uart->ustcnt |= USTCNT_TXEN | USTCNT_TX_INTR_MASK;
#else
      uart->ustcnt |= USTCNT_TXEN;
#endif

#ifdef USE_INTS
      if (uart->utx.w & UTX_TX_AVAIL) {
#else
      if (1) {
#endif
            /* Send char */
            uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
            info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
            info->xmit_cnt--;
      }

#ifndef USE_INTS
      while (!(uart->utx.w & UTX_TX_AVAIL)) udelay(5);
      }
#endif
      local_irq_restore(flags);
}

extern void console_printn(const char * b, int count);

static int rs_write(struct tty_struct * tty,
                const unsigned char *buf, int count)
{
      int   c, total = 0;
      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_write"))
            return 0;

      if (!tty || !info->xmit_buf)
            return 0;

      local_save_flags(flags);
      while (1) {
            local_irq_disable();          
            c = min_t(int, count, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
                           SERIAL_XMIT_SIZE - info->xmit_head));
            local_irq_restore(flags);

            if (c <= 0)
                  break;

            memcpy(info->xmit_buf + info->xmit_head, buf, c);

            local_irq_disable();
            info->xmit_head = (info->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
            info->xmit_cnt += c;
            local_irq_restore(flags);
            buf += c;
            count -= c;
            total += c;
      }

      if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped) {
            /* Enable transmitter */
            local_irq_disable();          
#ifndef USE_INTS
            while(info->xmit_cnt) {
#endif

            uart->ustcnt |= USTCNT_TXEN;
#ifdef USE_INTS
            uart->ustcnt |= USTCNT_TX_INTR_MASK;
#else
            while (!(uart->utx.w & UTX_TX_AVAIL)) udelay(5);
#endif
            if (uart->utx.w & UTX_TX_AVAIL) {
                  uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
                  info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
                  info->xmit_cnt--;
            }

#ifndef USE_INTS
            }
#endif
            local_irq_restore(flags);
      }

      return total;
}

static int rs_write_room(struct tty_struct *tty)
{
      struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
      int   ret;
                        
      if (serial_paranoia_check(info, tty->name, "rs_write_room"))
            return 0;
      ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
      if (ret < 0)
            ret = 0;
      return ret;
}

static int rs_chars_in_buffer(struct tty_struct *tty)
{
      struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
                        
      if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
            return 0;
      return info->xmit_cnt;
}

static void rs_flush_buffer(struct tty_struct *tty)
{
      struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
      unsigned long flags;
                        
      if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
            return;
      local_irq_save(flags);
      info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
      local_irq_restore(flags);
      tty_wakeup(tty);
}

/*
 * ------------------------------------------------------------
 * rs_throttle()
 * 
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void rs_throttle(struct tty_struct * tty)
{
      struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;

      if (serial_paranoia_check(info, tty->name, "rs_throttle"))
            return;
      
      if (I_IXOFF(tty))
            info->x_char = STOP_CHAR(tty);

      /* Turn off RTS line (do this atomic) */
}

static void rs_unthrottle(struct tty_struct * tty)
{
      struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;

      if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
            return;
      
      if (I_IXOFF(tty)) {
            if (info->x_char)
                  info->x_char = 0;
            else
                  info->x_char = START_CHAR(tty);
      }

      /* Assert RTS line (do this atomic) */
}

/*
 * ------------------------------------------------------------
 * rs_ioctl() and friends
 * ------------------------------------------------------------
 */

static int get_serial_info(struct m68k_serial * info,
                     struct serial_struct * retinfo)
{
      struct serial_struct tmp;
  
      if (!retinfo)
            return -EFAULT;
      memset(&tmp, 0, sizeof(tmp));
      tmp.type = info->type;
      tmp.line = info->line;
      tmp.port = info->port;
      tmp.irq = info->irq;
      tmp.flags = info->flags;
      tmp.baud_base = info->baud_base;
      tmp.close_delay = info->close_delay;
      tmp.closing_wait = info->closing_wait;
      tmp.custom_divisor = info->custom_divisor;
      copy_to_user(retinfo,&tmp,sizeof(*retinfo));
      return 0;
}

static int set_serial_info(struct m68k_serial * info,
                     struct serial_struct * new_info)
{
      struct serial_struct new_serial;
      struct m68k_serial old_info;
      int               retval = 0;

      if (!new_info)
            return -EFAULT;
      copy_from_user(&new_serial,new_info,sizeof(new_serial));
      old_info = *info;

      if (!capable(CAP_SYS_ADMIN)) {
            if ((new_serial.baud_base != info->baud_base) ||
                (new_serial.type != info->type) ||
                (new_serial.close_delay != info->close_delay) ||
                ((new_serial.flags & ~S_USR_MASK) !=
                 (info->flags & ~S_USR_MASK)))
                  return -EPERM;
            info->flags = ((info->flags & ~S_USR_MASK) |
                         (new_serial.flags & S_USR_MASK));
            info->custom_divisor = new_serial.custom_divisor;
            goto check_and_exit;
      }

      if (info->count > 1)
            return -EBUSY;

      /*
       * OK, past this point, all the error checking has been done.
       * At this point, we start making changes.....
       */

      info->baud_base = new_serial.baud_base;
      info->flags = ((info->flags & ~S_FLAGS) |
                  (new_serial.flags & S_FLAGS));
      info->type = new_serial.type;
      info->close_delay = new_serial.close_delay;
      info->closing_wait = new_serial.closing_wait;

check_and_exit:
      retval = startup(info);
      return retval;
}

/*
 * get_lsr_info - get line status register info
 *
 * Purpose: Let user call ioctl() to get info when the UART physically
 *        is emptied.  On bus types like RS485, the transmitter must
 *        release the bus after transmitting. This must be done when
 *        the transmit shift register is empty, not be done when the
 *        transmit holding register is empty.  This functionality
 *        allows an RS485 driver to be written in user space. 
 */
static int get_lsr_info(struct m68k_serial * info, unsigned int *value)
{
#ifdef CONFIG_SERIAL_68328_RTS_CTS
      m68328_uart *uart = &uart_addr[info->line];
#endif
      unsigned char status;
      unsigned long flags;

      local_irq_save(flags);
#ifdef CONFIG_SERIAL_68328_RTS_CTS
      status = (uart->utx.w & UTX_CTS_STAT) ? 1 : 0;
#else
      status = 0;
#endif
      local_irq_restore(flags);
      put_user(status,value);
      return 0;
}

/*
 * This routine sends a break character out the serial port.
 */
static void send_break(struct m68k_serial * info, unsigned int duration)
{
      m68328_uart *uart = &uart_addr[info->line];
        unsigned long flags;
        if (!info->port)
                return;
        local_irq_save(flags);
#ifdef USE_INTS   
      uart->utx.w |= UTX_SEND_BREAK;
      msleep_interruptible(duration);
      uart->utx.w &= ~UTX_SEND_BREAK;
#endif            
        local_irq_restore(flags);
}

static int rs_ioctl(struct tty_struct *tty, struct file * file,
                unsigned int cmd, unsigned long arg)
{
      int error;
      struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
      int retval;

      if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
            return -ENODEV;

      if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
          (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGWILD)  &&
          (cmd != TIOCSERSWILD) && (cmd != TIOCSERGSTRUCT)) {
            if (tty->flags & (1 << TTY_IO_ERROR))
                return -EIO;
      }
      
      switch (cmd) {
            case TCSBRK:      /* SVID version: non-zero arg --> no break */
                  retval = tty_check_change(tty);
                  if (retval)
                        return retval;
                  tty_wait_until_sent(tty, 0);
                  if (!arg)
                        send_break(info, 250);  /* 1/4 second */
                  return 0;
            case TCSBRKP:     /* support for POSIX tcsendbreak() */
                  retval = tty_check_change(tty);
                  if (retval)
                        return retval;
                  tty_wait_until_sent(tty, 0);
                  send_break(info, arg ? arg*(100) : 250);
                  return 0;
            case TIOCGSOFTCAR:
                  error = put_user(C_CLOCAL(tty) ? 1 : 0,
                            (unsigned long *) arg);
                  if (error)
                        return error;
                  return 0;
            case TIOCSSOFTCAR:
                  get_user(arg, (unsigned long *) arg);
                  tty->termios->c_cflag =
                        ((tty->termios->c_cflag & ~CLOCAL) |
                         (arg ? CLOCAL : 0));
                  return 0;
            case TIOCGSERIAL:
                  if (access_ok(VERIFY_WRITE, (void *) arg,
                                    sizeof(struct serial_struct)))
                        return get_serial_info(info,
                                     (struct serial_struct *) arg);
                  return -EFAULT;
            case TIOCSSERIAL:
                  return set_serial_info(info,
                                     (struct serial_struct *) arg);
            case TIOCSERGETLSR: /* Get line status register */
                  if (access_ok(VERIFY_WRITE, (void *) arg,
                                    sizeof(unsigned int)))
                        return get_lsr_info(info, (unsigned int *) arg);
                  return -EFAULT;
            case TIOCSERGSTRUCT:
                  if (!access_ok(VERIFY_WRITE, (void *) arg,
                                    sizeof(struct m68k_serial)))
                        return -EFAULT;
                  copy_to_user((struct m68k_serial *) arg,
                            info, sizeof(struct m68k_serial));
                  return 0;
                  
            default:
                  return -ENOIOCTLCMD;
            }
      return 0;
}

static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
      struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;

      if (tty->termios->c_cflag == old_termios->c_cflag)
            return;

      change_speed(info);

      if ((old_termios->c_cflag & CRTSCTS) &&
          !(tty->termios->c_cflag & CRTSCTS)) {
            tty->hw_stopped = 0;
            rs_start(tty);
      }
      
}

/*
 * ------------------------------------------------------------
 * rs_close()
 * 
 * This routine is called when the serial port gets closed.  First, we
 * wait for the last remaining data to be sent.  Then, we unlink its
 * S structure from the interrupt chain if necessary, and we free
 * that IRQ if nothing is left in the chain.
 * ------------------------------------------------------------
 */
static void rs_close(struct tty_struct *tty, struct file * filp)
{
      struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
      m68328_uart *uart = &uart_addr[info->line];
      unsigned long flags;

      if (!info || serial_paranoia_check(info, tty->name, "rs_close"))
            return;
      
      local_irq_save(flags);
      
      if (tty_hung_up_p(filp)) {
            local_irq_restore(flags);
            return;
      }
      
      if ((tty->count == 1) && (info->count != 1)) {
            /*
             * Uh, oh.  tty->count is 1, which means that the tty
             * structure will be freed.  Info->count should always
             * be one in these conditions.  If it's greater than
             * one, we've got real problems, since it means the
             * serial port won't be shutdown.
             */
            printk("rs_close: bad serial port count; tty->count is 1, "
                   "info->count is %d\n", info->count);
            info->count = 1;
      }
      if (--info->count < 0) {
            printk("rs_close: bad serial port count for ttyS%d: %d\n",
                   info->line, info->count);
            info->count = 0;
      }
      if (info->count) {
            local_irq_restore(flags);
            return;
      }
      info->flags |= S_CLOSING;
      /*
       * Now we wait for the transmit buffer to clear; and we notify 
       * the line discipline to only process XON/XOFF characters.
       */
      tty->closing = 1;
      if (info->closing_wait != S_CLOSING_WAIT_NONE)
            tty_wait_until_sent(tty, info->closing_wait);
      /*
       * At this point we stop accepting input.  To do this, we
       * disable the receive line status interrupts, and tell the
       * interrupt driver to stop checking the data ready bit in the
       * line status register.
       */

      uart->ustcnt &= ~USTCNT_RXEN;
      uart->ustcnt &= ~(USTCNT_RXEN | USTCNT_RX_INTR_MASK);

      shutdown(info);
      if (tty->driver->flush_buffer)
            tty->driver->flush_buffer(tty);
            
      tty_ldisc_flush(tty);
      tty->closing = 0;
      info->event = 0;
      info->tty = 0;
#warning "This is not and has never been valid so fix it"   
#if 0
      if (tty->ldisc.num != ldiscs[N_TTY].num) {
            if (tty->ldisc.close)
                  (tty->ldisc.close)(tty);
            tty->ldisc = ldiscs[N_TTY];
            tty->termios->c_line = N_TTY;
            if (tty->ldisc.open)
                  (tty->ldisc.open)(tty);
      }
#endif      
      if (info->blocked_open) {
            if (info->close_delay) {
                  msleep_interruptible(jiffies_to_msecs(info->close_delay));
            }
            wake_up_interruptible(&info->open_wait);
      }
      info->flags &= ~(S_NORMAL_ACTIVE|S_CLOSING);
      wake_up_interruptible(&info->close_wait);
      local_irq_restore(flags);
}

/*
 * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
void rs_hangup(struct tty_struct *tty)
{
      struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
      
      if (serial_paranoia_check(info, tty->name, "rs_hangup"))
            return;
      
      rs_flush_buffer(tty);
      shutdown(info);
      info->event = 0;
      info->count = 0;
      info->flags &= ~S_NORMAL_ACTIVE;
      info->tty = 0;
      wake_up_interruptible(&info->open_wait);
}

/*
 * ------------------------------------------------------------
 * rs_open() and friends
 * ------------------------------------------------------------
 */
static int block_til_ready(struct tty_struct *tty, struct file * filp,
                     struct m68k_serial *info)
{
      DECLARE_WAITQUEUE(wait, current);
      int         retval;
      int         do_clocal = 0;

      /*
       * If the device is in the middle of being closed, then block
       * until it's done, and then try again.
       */
      if (info->flags & S_CLOSING) {
            interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
            if (info->flags & S_HUP_NOTIFY)
                  return -EAGAIN;
            else
                  return -ERESTARTSYS;
#else
            return -EAGAIN;
#endif
      }
      
      /*
       * If non-blocking mode is set, or the port is not enabled,
       * then make the check up front and then exit.
       */
      if ((filp->f_flags & O_NONBLOCK) ||
          (tty->flags & (1 << TTY_IO_ERROR))) {
            info->flags |= S_NORMAL_ACTIVE;
            return 0;
      }

      if (tty->termios->c_cflag & CLOCAL)
            do_clocal = 1;

      /*
       * Block waiting for the carrier detect and the line to become
       * free (i.e., not in use by the callout).  While we are in
       * this loop, info->count is dropped by one, so that
       * rs_close() knows when to free things.  We restore it upon
       * exit, either normal or abnormal.
       */
      retval = 0;
      add_wait_queue(&info->open_wait, &wait);

      info->count--;
      info->blocked_open++;
      while (1) {
            local_irq_disable();
            m68k_rtsdtr(info, 1);
            local_irq_enable();
            current->state = TASK_INTERRUPTIBLE;
            if (tty_hung_up_p(filp) ||
                !(info->flags & S_INITIALIZED)) {
#ifdef SERIAL_DO_RESTART
                  if (info->flags & S_HUP_NOTIFY)
                        retval = -EAGAIN;
                  else
                        retval = -ERESTARTSYS;  
#else
                  retval = -EAGAIN;
#endif
                  break;
            }
            if (!(info->flags & S_CLOSING) && do_clocal)
                  break;
                if (signal_pending(current)) {
                  retval = -ERESTARTSYS;
                  break;
            }
            schedule();
      }
      current->state = TASK_RUNNING;
      remove_wait_queue(&info->open_wait, &wait);
      if (!tty_hung_up_p(filp))
            info->count++;
      info->blocked_open--;

      if (retval)
            return retval;
      info->flags |= S_NORMAL_ACTIVE;
      return 0;
}     

/*
 * This routine is called whenever a serial port is opened.  It
 * enables interrupts for a serial port, linking in its S structure into
 * the IRQ chain.   It also performs the serial-specific
 * initialization for the tty structure.
 */
int rs_open(struct tty_struct *tty, struct file * filp)
{
      struct m68k_serial      *info;
      int               retval, line;

      line = tty->index;
      
      if (line >= NR_PORTS || line < 0) /* we have exactly one */
            return -ENODEV;

      info = &m68k_soft[line];

      if (serial_paranoia_check(info, tty->name, "rs_open"))
            return -ENODEV;

      info->count++;
      tty->driver_data = info;
      info->tty = tty;

      /*
       * Start up serial port
       */
      retval = startup(info);
      if (retval)
            return retval;

      return block_til_ready(tty, filp, info);
}

/* Finally, routines used to initialize the serial driver. */

static void show_serial_version(void)
{
      printk("MC68328 serial driver version 1.00\n");
}

static const struct tty_operations rs_ops = {
      .open = rs_open,
      .close = rs_close,
      .write = rs_write,
      .flush_chars = rs_flush_chars,
      .write_room = rs_write_room,
      .chars_in_buffer = rs_chars_in_buffer,
      .flush_buffer = rs_flush_buffer,
      .ioctl = rs_ioctl,
      .throttle = rs_throttle,
      .unthrottle = rs_unthrottle,
      .set_termios = rs_set_termios,
      .stop = rs_stop,
      .start = rs_start,
      .hangup = rs_hangup,
      .set_ldisc = rs_set_ldisc,
};

/* rs_init inits the driver */
static int __init
rs68328_init(void)
{
      int flags, i;
      struct m68k_serial *info;

      serial_driver = alloc_tty_driver(NR_PORTS);
      if (!serial_driver)
            return -ENOMEM;

      show_serial_version();

      /* Initialize the tty_driver structure */
      /* SPARC: Not all of this is exactly right for us. */
      
      serial_driver->name = "ttyS";
      serial_driver->major = TTY_MAJOR;
      serial_driver->minor_start = 64;
      serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
      serial_driver->subtype = SERIAL_TYPE_NORMAL;
      serial_driver->init_termios = tty_std_termios;
      serial_driver->init_termios.c_cflag = 
                  m68328_console_cbaud | CS8 | CREAD | HUPCL | CLOCAL;
      serial_driver->flags = TTY_DRIVER_REAL_RAW;
      tty_set_operations(serial_driver, &rs_ops);

      if (tty_register_driver(serial_driver)) {
            put_tty_driver(serial_driver);
            printk(KERN_ERR "Couldn't register serial driver\n");
            return -ENOMEM;
      }

      local_irq_save(flags);

      for(i=0;i<NR_PORTS;i++) {

          info = &m68k_soft[i];
          info->magic = SERIAL_MAGIC;
          info->port = (int) &uart_addr[i];
          info->tty = 0;
          info->irq = uart_irqs[i];
          info->custom_divisor = 16;
          info->close_delay = 50;
          info->closing_wait = 3000;
          info->x_char = 0;
          info->event = 0;
          info->count = 0;
          info->blocked_open = 0;
          INIT_WORK(&info->tqueue, do_softint);
          INIT_WORK(&info->tqueue_hangup, do_serial_hangup);
          init_waitqueue_head(&info->open_wait);
          init_waitqueue_head(&info->close_wait);
          info->line = i;
          info->is_cons = 1; /* Means shortcuts work */
          
          printk("%s%d at 0x%08x (irq = %d)", serial_driver->name, info->line, 
               info->port, info->irq);
          printk(" is a builtin MC68328 UART\n");
          
          IRQ_ports[info->irq] = info;    /* waste of space */

#ifdef CONFIG_M68VZ328
            if (i > 0 )
                  PJSEL &= 0xCF;  /* PSW enable second port output */
#endif

          if (request_irq(uart_irqs[i],
                      rs_interrupt,
                      IRQ_FLG_STD,
                      "M68328_UART", NULL))
                panic("Unable to attach 68328 serial interrupt\n");
      }
      local_irq_restore(flags);
      return 0;
}

module_init(rs68328_init);



static void m68328_set_baud(void)
{
      unsigned short ustcnt;
      int   i;

      ustcnt = USTCNT;
      USTCNT = ustcnt & ~USTCNT_TXEN;

again:
      for (i = 0; i < sizeof(baud_table) / sizeof(baud_table[0]); i++)
            if (baud_table[i] == m68328_console_baud)
                  break;
      if (i >= sizeof(baud_table) / sizeof(baud_table[0])) {
            m68328_console_baud = 9600;
            goto again;
      }

      UBAUD = PUT_FIELD(UBAUD_DIVIDE,    hw_baud_table[i].divisor) | 
            PUT_FIELD(UBAUD_PRESCALER, hw_baud_table[i].prescale);
      ustcnt &= ~(USTCNT_PARITYEN | USTCNT_ODD_EVEN | USTCNT_STOP | USTCNT_8_7);
      ustcnt |= USTCNT_8_7;
      ustcnt |= USTCNT_TXEN;
      USTCNT = ustcnt;
      m68328_console_initted = 1;
      return;
}


int m68328_console_setup(struct console *cp, char *arg)
{
      int         i, n = CONSOLE_BAUD_RATE;

      if (!cp)
            return(-1);

      if (arg)
            n = simple_strtoul(arg,NULL,0);

      for (i = 0; i < BAUD_TABLE_SIZE; i++)
            if (baud_table[i] == n)
                  break;
      if (i < BAUD_TABLE_SIZE) {
            m68328_console_baud = n;
            m68328_console_cbaud = 0;
            if (i > 15) {
                  m68328_console_cbaud |= CBAUDEX;
                  i -= 15;
            }
            m68328_console_cbaud |= i;
      }

      m68328_set_baud(); /* make sure baud rate changes */
      return(0);
}


static struct tty_driver *m68328_console_device(struct console *c, int *index)
{
      *index = c->index;
      return serial_driver;
}


void m68328_console_write (struct console *co, const char *str,
                     unsigned int count)
{
      if (!m68328_console_initted)
            m68328_set_baud();
    while (count--) {
        if (*str == '\n')
           rs_put_char('\r');
        rs_put_char( *str++ );
    }
}


static struct console m68328_driver = {
      .name       = "ttyS",
      .write            = m68328_console_write,
      .device           = m68328_console_device,
      .setup            = m68328_console_setup,
      .flags            = CON_PRINTBUFFER,
      .index            = -1,
};


static int __init m68328_console_init(void)
{
      register_console(&m68328_driver);
      return 0;
}

console_initcall(m68328_console_init);

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