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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [drivers/] [tc/] [zs.c] - Blame information for rev 1765

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/*
 * decserial.c: Serial port driver for IOASIC DECstations.
 *
 * Derived from drivers/sbus/char/sunserial.c by Paul Mackerras.
 * Derived from drivers/macintosh/macserial.c by Harald Koerfgen.
 *
 * DECstation changes
 * Copyright (C) 1998-2000 Harald Koerfgen
 * Copyright (C) 2000, 2001, 2002, 2003, 2004  Maciej W. Rozycki
 *
 * For the rest of the code the original Copyright applies:
 * Copyright (C) 1996 Paul Mackerras (Paul.Mackerras@cs.anu.edu.au)
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 *
 *
 * Note: for IOASIC systems the wiring is as follows:
 *
 * mouse/keyboard:
 * DIN-7 MJ-4  signal        SCC
 * 2     1     TxD       <-  A.TxD
 * 3     4     RxD       ->  A.RxD
 *
 * EIA-232/EIA-423:
 * DB-25 MMJ-6 signal        SCC
 * 2     2     TxD       <-  B.TxD
 * 3     5     RxD       ->  B.RxD
 * 4           RTS       <- ~A.RTS
 * 5           CTS       -> ~B.CTS
 * 6     6     DSR       -> ~A.SYNC
 * 8           CD        -> ~B.DCD
 * 12          DSRS(DCE) -> ~A.CTS  (*)
 * 15          TxC       ->  B.TxC
 * 17          RxC       ->  B.RxC
 * 20    1     DTR       <- ~A.DTR
 * 22          RI        -> ~A.DCD
 * 23          DSRS(DTE) <- ~B.RTS
 *
 * (*) EIA-232 defines the signal at this pin to be SCD, while DSRS(DCE)
 *     is shared with DSRS(DTE) at pin 23.
 */
 
#include <linux/config.h>
#include <linux/version.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/delay.h>
#include <linux/init.h>
#include <linux/ioport.h>
#ifdef CONFIG_SERIAL_DEC_CONSOLE
#include <linux/console.h>
#endif
 
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/segment.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
#include <asm/bootinfo.h>
#ifdef CONFIG_DECSTATION
#include <asm/dec/interrupts.h>
#include <asm/dec/machtype.h>
#include <asm/dec/tc.h>
#include <asm/dec/ioasic_addrs.h>
#endif
#ifdef CONFIG_BAGET_MIPS
#include <asm/baget/baget.h>
unsigned long system_base;
#endif
#ifdef CONFIG_KGDB
#include <asm/kgdb.h>
#endif
#ifdef CONFIG_MAGIC_SYSRQ
#include <linux/sysrq.h>
#endif
 
#include "zs.h"
 
/*
 * It would be nice to dynamically allocate everything that
 * depends on NUM_SERIAL, so we could support any number of
 * Z8530s, but for now...
 */
#define NUM_SERIAL      2               /* Max number of ZS chips supported */
#define NUM_CHANNELS    (NUM_SERIAL * 2)        /* 2 channels per chip */
#define CHANNEL_A_NR  (zs_parms->channel_a_offset > zs_parms->channel_b_offset)
                                        /* Number of channel A in the chip */
#define ZS_CHAN_IO_SIZE 8
#define ZS_CLOCK        7372800         /* Z8530 RTxC input clock rate */
 
#define RECOVERY_DELAY  udelay(2)
 
struct zs_parms {
        unsigned long scc0;
        unsigned long scc1;
        int channel_a_offset;
        int channel_b_offset;
        int irq0;
        int irq1;
        int clock;
};
 
static struct zs_parms *zs_parms;
 
#ifdef CONFIG_DECSTATION
static struct zs_parms ds_parms = {
        scc0 : IOASIC_SCC0,
        scc1 : IOASIC_SCC1,
        channel_a_offset : 1,
        channel_b_offset : 9,
        irq0 : -1,
        irq1 : -1,
        clock : ZS_CLOCK
};
#endif
#ifdef CONFIG_BAGET_MIPS
static struct zs_parms baget_parms = {
        scc0 : UNI_SCC0,
        scc1 : UNI_SCC1,
        channel_a_offset : 9,
        channel_b_offset : 1,
        irq0 : BAGET_SCC_IRQ,
        irq1 : BAGET_SCC_IRQ,
        clock : 14745000
};
#endif
 
#ifdef CONFIG_DECSTATION
#define DS_BUS_PRESENT (IOASIC)
#else
#define DS_BUS_PRESENT 0
#endif
 
#ifdef CONFIG_BAGET_MIPS
#define BAGET_BUS_PRESENT (mips_machtype == MACH_BAGET202)
#else
#define BAGET_BUS_PRESENT 0
#endif
 
#define BUS_PRESENT (DS_BUS_PRESENT || BAGET_BUS_PRESENT)
 
struct dec_zschannel zs_channels[NUM_CHANNELS];
struct dec_serial zs_soft[NUM_CHANNELS];
int zs_channels_found;
struct dec_serial *zs_chain;    /* list of all channels */
 
struct tty_struct zs_ttys[NUM_CHANNELS];
 
#ifdef CONFIG_SERIAL_DEC_CONSOLE
static struct console sercons;
#endif
#if defined(CONFIG_SERIAL_DEC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) \
    && !defined(MODULE)
static unsigned long break_pressed; /* break, really ... */
#endif
 
static unsigned char zs_init_regs[16] __initdata = {
        0,                               /* write 0 */
        0,                               /* write 1 */
        0,                               /* write 2 */
        0,                               /* write 3 */
        (X16CLK),                       /* write 4 */
        0,                               /* write 5 */
        0, 0, 0,                   /* write 6, 7, 8 */
        (MIE | DLC | NV),               /* write 9 */
        (NRZ),                          /* write 10 */
        (TCBR | RCBR),                  /* write 11 */
        0, 0,                             /* BRG time constant, write 12 + 13 */
        (BRSRC | BRENABL),              /* write 14 */
 
};
 
DECLARE_TASK_QUEUE(tq_zs_serial);
 
struct tty_driver serial_driver, callout_driver;
static int serial_refcount;
 
/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL      1
#define SERIAL_TYPE_CALLOUT     2
 
/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256
 
/*
 * Debugging.
 */
#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW
#undef SERIAL_DEBUG_THROTTLE
#undef SERIAL_PARANOIA_CHECK
 
#undef ZS_DEBUG_REGS
 
#ifdef SERIAL_DEBUG_THROTTLE
#define _tty_name(tty,buf) tty_name(tty,buf)
#endif
 
#define RS_STROBE_TIME 10
#define RS_ISR_PASS_LIMIT 256
 
#define _INLINE_ inline
 
static void probe_sccs(void);
static void change_speed(struct dec_serial *info);
static void rs_wait_until_sent(struct tty_struct *tty, int timeout);
 
static struct tty_struct *serial_table[NUM_CHANNELS];
static struct termios *serial_termios[NUM_CHANNELS];
static struct termios *serial_termios_locked[NUM_CHANNELS];
 
#ifndef MIN
#define MIN(a,b)        ((a) < (b) ? (a) : (b))
#endif
 
/*
 * tmp_buf is used as a temporary buffer by serial_write.  We need to
 * lock it in case the copy_from_user blocks while swapping in a page,
 * and some other program tries to do a serial write at the same time.
 * Since the lock will only come under contention when the system is
 * swapping and available memory is low, it makes sense to share one
 * buffer across all the serial ports, since it significantly saves
 * memory if large numbers of serial ports are open.
 */
static unsigned char tmp_buf[4096]; /* This is cheating */
static DECLARE_MUTEX(tmp_buf_sem);
 
static inline int serial_paranoia_check(struct dec_serial *info,
                                        dev_t device, const char *routine)
{
#ifdef SERIAL_PARANOIA_CHECK
        static const char *badmagic =
                "Warning: bad magic number for serial struct (%d, %d) in %s\n";
        static const char *badinfo =
                "Warning: null mac_serial for (%d, %d) in %s\n";
 
        if (!info) {
                printk(badinfo, MAJOR(device), MINOR(device), routine);
                return 1;
        }
        if (info->magic != SERIAL_MAGIC) {
                printk(badmagic, MAJOR(device), MINOR(device), 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 };
 
/*
 * Reading and writing Z8530 registers.
 */
static inline unsigned char read_zsreg(struct dec_zschannel *channel,
                                       unsigned char reg)
{
        unsigned char retval;
 
        if (reg != 0) {
                *channel->control = reg & 0xf;
                fast_iob(); RECOVERY_DELAY;
        }
        retval = *channel->control;
        RECOVERY_DELAY;
        return retval;
}
 
static inline void write_zsreg(struct dec_zschannel *channel,
                               unsigned char reg, unsigned char value)
{
        if (reg != 0) {
                *channel->control = reg & 0xf;
                fast_iob(); RECOVERY_DELAY;
        }
        *channel->control = value;
        fast_iob(); RECOVERY_DELAY;
        return;
}
 
static inline unsigned char read_zsdata(struct dec_zschannel *channel)
{
        unsigned char retval;
 
        retval = *channel->data;
        RECOVERY_DELAY;
        return retval;
}
 
static inline void write_zsdata(struct dec_zschannel *channel,
                                unsigned char value)
{
        *channel->data = value;
        fast_iob(); RECOVERY_DELAY;
        return;
}
 
static inline void load_zsregs(struct dec_zschannel *channel,
                               unsigned char *regs)
{
/*      ZS_CLEARERR(channel);
        ZS_CLEARFIFO(channel); */
        /* Load 'em up */
        write_zsreg(channel, R3, regs[R3] & ~RxENABLE);
        write_zsreg(channel, R5, regs[R5] & ~TxENAB);
        write_zsreg(channel, R4, regs[R4]);
        write_zsreg(channel, R9, regs[R9]);
        write_zsreg(channel, R1, regs[R1]);
        write_zsreg(channel, R2, regs[R2]);
        write_zsreg(channel, R10, regs[R10]);
        write_zsreg(channel, R11, regs[R11]);
        write_zsreg(channel, R12, regs[R12]);
        write_zsreg(channel, R13, regs[R13]);
        write_zsreg(channel, R14, regs[R14]);
        write_zsreg(channel, R15, regs[R15]);
        write_zsreg(channel, R3, regs[R3]);
        write_zsreg(channel, R5, regs[R5]);
        return;
}
 
/* Sets or clears DTR/RTS on the requested line */
static inline void zs_rtsdtr(struct dec_serial *info, int which, int set)
{
        unsigned long flags;
 
 
        save_flags(flags); cli();
        if (info->zs_channel != info->zs_chan_a) {
                if (set) {
                        info->zs_chan_a->curregs[5] |= (which & (RTS | DTR));
                } else {
                        info->zs_chan_a->curregs[5] &= ~(which & (RTS | DTR));
                }
                write_zsreg(info->zs_chan_a, 5, info->zs_chan_a->curregs[5]);
        }
        restore_flags(flags);
}
 
/* Utility routines for the Zilog */
static inline int get_zsbaud(struct dec_serial *ss)
{
        struct dec_zschannel *channel = ss->zs_channel;
        int brg;
 
        /* The baud rate is split up between two 8-bit registers in
         * what is termed 'BRG time constant' format in my docs for
         * the chip, it is a function of the clk rate the chip is
         * receiving which happens to be constant.
         */
        brg = (read_zsreg(channel, 13) << 8);
        brg |= read_zsreg(channel, 12);
        return BRG_TO_BPS(brg, (zs_parms->clock/(ss->clk_divisor)));
}
 
/* On receive, this clears errors and the receiver interrupts */
static inline void rs_recv_clear(struct dec_zschannel *zsc)
{
        write_zsreg(zsc, 0, ERR_RES);
        write_zsreg(zsc, 0, RES_H_IUS); /* XXX this is unnecessary */
}
 
/*
 * ----------------------------------------------------------------------
 *
 * Here starts the interrupt handling routines.  All of the following
 * subroutines are declared as inline and are folded into
 * rs_interrupt().  They were separated out for readability's sake.
 *
 *                              - Ted Ts'o (tytso@mit.edu), 7-Mar-93
 * -----------------------------------------------------------------------
 */
 
static int tty_break;   /* Set whenever BREAK condition is detected.  */
 
/*
 * This routine is used by the interrupt handler to schedule
 * processing in the software interrupt portion of the driver.
 */
static _INLINE_ void rs_sched_event(struct dec_serial *info,
                                  int event)
{
        info->event |= 1 << event;
        queue_task(&info->tqueue, &tq_zs_serial);
        mark_bh(SERIAL_BH);
}
 
static _INLINE_ void receive_chars(struct dec_serial *info,
                                   struct pt_regs *regs)
{
        struct tty_struct *tty = info->tty;
        unsigned char ch, stat, flag;
 
        while ((read_zsreg(info->zs_channel, R0) & Rx_CH_AV) != 0) {
 
                stat = read_zsreg(info->zs_channel, R1);
                ch = read_zsdata(info->zs_channel);
 
                if (!tty && (!info->hook || !info->hook->rx_char))
                        continue;
 
                if (tty_break) {
                        tty_break = 0;
#if defined(CONFIG_SERIAL_DEC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) && !defined(MODULE)
                        if (info->line == sercons.index) {
                                if (!break_pressed) {
                                        break_pressed = jiffies;
                                        goto ignore_char;
                                }
                                break_pressed = 0;
                        }
#endif
                        flag = TTY_BREAK;
                        if (info->flags & ZILOG_SAK)
                                do_SAK(tty);
                } else {
                        if (stat & Rx_OVR) {
                                flag = TTY_OVERRUN;
                        } else if (stat & FRM_ERR) {
                                flag = TTY_FRAME;
                        } else if (stat & PAR_ERR) {
                                flag = TTY_PARITY;
                        } else
                                flag = 0;
                        if (flag)
                                /* reset the error indication */
                                write_zsreg(info->zs_channel, R0, ERR_RES);
                }
 
#if defined(CONFIG_SERIAL_DEC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) && !defined(MODULE)
                if (break_pressed && info->line == sercons.index) {
                        if (ch != 0 &&
                            time_before(jiffies, break_pressed + HZ*5)) {
                                handle_sysrq(ch, regs, NULL, NULL);
                                break_pressed = 0;
                                goto ignore_char;
                        }
                        break_pressed = 0;
                }
#endif
 
                if (info->hook && info->hook->rx_char) {
                        (*info->hook->rx_char)(ch, flag);
                        return;
                }
 
                if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
                        static int flip_buf_ovf;
                        ++flip_buf_ovf;
                        continue;
                }
                tty->flip.count++;
                {
                        static int flip_max_cnt;
                        if (flip_max_cnt < tty->flip.count)
                                flip_max_cnt = tty->flip.count;
                }
 
                *tty->flip.flag_buf_ptr++ = flag;
                *tty->flip.char_buf_ptr++ = ch;
#if defined(CONFIG_SERIAL_DEC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) && !defined(MODULE)
        ignore_char:
#endif
        }
        if (tty)
                tty_flip_buffer_push(tty);
}
 
static void transmit_chars(struct dec_serial *info)
{
        if ((read_zsreg(info->zs_channel, R0) & Tx_BUF_EMP) == 0)
                return;
        info->tx_active = 0;
 
        if (info->x_char) {
                /* Send next char */
                write_zsdata(info->zs_channel, info->x_char);
                info->x_char = 0;
                info->tx_active = 1;
                return;
        }
 
        if ((info->xmit_cnt <= 0) || (info->tty && info->tty->stopped)
            || info->tx_stopped) {
                write_zsreg(info->zs_channel, R0, RES_Tx_P);
                return;
        }
        /* Send char */
        write_zsdata(info->zs_channel, info->xmit_buf[info->xmit_tail++]);
        info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
        info->xmit_cnt--;
        info->tx_active = 1;
 
        if (info->xmit_cnt < WAKEUP_CHARS)
                rs_sched_event(info, RS_EVENT_WRITE_WAKEUP);
}
 
static _INLINE_ void status_handle(struct dec_serial *info)
{
        unsigned char stat;
 
        /* Get status from Read Register 0 */
        stat = read_zsreg(info->zs_channel, R0);
 
        if (stat & BRK_ABRT) {
#ifdef SERIAL_DEBUG_INTR
                printk("handling break....");
#endif
                tty_break = 1;
        }
 
        if (info->zs_channel != info->zs_chan_a) {
 
                /* Check for DCD transitions */
                if (info->tty && !C_CLOCAL(info->tty) &&
                    ((stat ^ info->read_reg_zero) & DCD) != 0 ) {
                        if (stat & DCD) {
                                wake_up_interruptible(&info->open_wait);
                        } else if (!(info->flags & ZILOG_CALLOUT_ACTIVE)) {
                                tty_hangup(info->tty);
                        }
                }
 
                /* Check for CTS transitions */
                if (info->tty && C_CRTSCTS(info->tty)) {
                        if ((stat & CTS) != 0) {
                                if (info->tx_stopped) {
                                        info->tx_stopped = 0;
                                        if (!info->tx_active)
                                                transmit_chars(info);
                                }
                        } else {
                                info->tx_stopped = 1;
                        }
                }
 
        }
 
        /* Clear status condition... */
        write_zsreg(info->zs_channel, R0, RES_EXT_INT);
        info->read_reg_zero = stat;
}
 
/*
 * This is the serial driver's generic interrupt routine
 */
void rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        struct dec_serial *info = (struct dec_serial *) dev_id;
        unsigned char zs_intreg;
        int shift;
 
        /* NOTE: The read register 3, which holds the irq status,
         *       does so for both channels on each chip.  Although
         *       the status value itself must be read from the A
         *       channel and is only valid when read from channel A.
         *       Yes... broken hardware...
         */
#define CHAN_IRQMASK (CHBRxIP | CHBTxIP | CHBEXT)
 
        if (info->zs_chan_a == info->zs_channel)
                shift = 3;      /* Channel A */
        else
                shift = 0;       /* Channel B */
 
        for (;;) {
                zs_intreg = read_zsreg(info->zs_chan_a, R3) >> shift;
                if ((zs_intreg & CHAN_IRQMASK) == 0)
                        break;
 
                if (zs_intreg & CHBRxIP) {
                        receive_chars(info, regs);
                }
                if (zs_intreg & CHBTxIP) {
                        transmit_chars(info);
                }
                if (zs_intreg & CHBEXT) {
                        status_handle(info);
                }
        }
 
        /* Why do we need this ? */
        write_zsreg(info->zs_channel, 0, RES_H_IUS);
}
 
#ifdef ZS_DEBUG_REGS
void zs_dump (void) {
        int i, j;
        for (i = 0; i < zs_channels_found; i++) {
                struct dec_zschannel *ch = &zs_channels[i];
                if ((long)ch->control == UNI_IO_BASE+UNI_SCC1A_CTRL) {
                        for (j = 0; j < 15; j++) {
                                printk("W%d = 0x%x\t",
                                       j, (int)ch->curregs[j]);
                        }
                        for (j = 0; j < 15; j++) {
                                printk("R%d = 0x%x\t",
                                       j, (int)read_zsreg(ch,j));
                        }
                        printk("\n\n");
                }
        }
}
#endif
 
/*
 * -------------------------------------------------------------------
 * Here ends the serial interrupt routines.
 * -------------------------------------------------------------------
 */
 
/*
 * ------------------------------------------------------------
 * rs_stop() and rs_start()
 *
 * This routines are called before setting or resetting tty->stopped.
 * ------------------------------------------------------------
 */
static void rs_stop(struct tty_struct *tty)
{
        struct dec_serial *info = (struct dec_serial *)tty->driver_data;
        unsigned long flags;
 
        if (serial_paranoia_check(info, tty->device, "rs_stop"))
                return;
 
#if 1
        save_flags(flags); cli();
        if (info->zs_channel->curregs[5] & TxENAB) {
                info->zs_channel->curregs[5] &= ~TxENAB;
                write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
        }
        restore_flags(flags);
#endif
}
 
static void rs_start(struct tty_struct *tty)
{
        struct dec_serial *info = (struct dec_serial *)tty->driver_data;
        unsigned long flags;
 
        if (serial_paranoia_check(info, tty->device, "rs_start"))
                return;
 
        save_flags(flags); cli();
#if 1
        if (info->xmit_cnt && info->xmit_buf && !(info->zs_channel->curregs[5] & TxENAB)) {
                info->zs_channel->curregs[5] |= TxENAB;
                write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
        }
#else
        if (info->xmit_cnt && info->xmit_buf && !info->tx_active) {
                transmit_chars(info);
        }
#endif
        restore_flags(flags);
}
 
/*
 * This routine is used to handle the "bottom half" processing for the
 * serial driver, known also the "software interrupt" processing.
 * This processing is done at the kernel interrupt level, after the
 * rs_interrupt() has returned, BUT WITH INTERRUPTS TURNED ON.  This
 * is where time-consuming activities which can not be done in the
 * interrupt driver proper are done; the interrupt driver schedules
 * them using rs_sched_event(), and they get done here.
 */
static void do_serial_bh(void)
{
        run_task_queue(&tq_zs_serial);
}
 
static void do_softint(void *private_)
{
        struct dec_serial       *info = (struct dec_serial *) private_;
        struct tty_struct       *tty;
 
        tty = info->tty;
        if (!tty)
                return;
 
        if (test_and_clear_bit(RS_EVENT_WRITE_WAKEUP, &info->event)) {
                if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
                    tty->ldisc.write_wakeup)
                        (tty->ldisc.write_wakeup)(tty);
                wake_up_interruptible(&tty->write_wait);
        }
}
 
int zs_startup(struct dec_serial * info)
{
        unsigned long flags;
 
        if (info->flags & ZILOG_INITIALIZED)
                return 0;
 
        if (!info->xmit_buf) {
                info->xmit_buf = (unsigned char *) get_free_page(GFP_KERNEL);
                if (!info->xmit_buf)
                        return -ENOMEM;
        }
 
        save_flags(flags); cli();
 
#ifdef SERIAL_DEBUG_OPEN
        printk("starting up ttyS%02d (irq %d)...", info->line, info->irq);
#endif
 
        /*
         * Clear the receive FIFO.
         */
        ZS_CLEARFIFO(info->zs_channel);
        info->xmit_fifo_size = 1;
 
        /*
         * Clear the interrupt registers.
         */
        write_zsreg(info->zs_channel, R0, ERR_RES);
        write_zsreg(info->zs_channel, R0, RES_H_IUS);
 
        /*
         * Set the speed of the serial port
         */
        change_speed(info);
 
        /*
         * Turn on RTS and DTR.
         */
        zs_rtsdtr(info, RTS | DTR, 1);
 
        /*
         * Finally, enable sequencing and interrupts
         */
        info->zs_channel->curregs[R1] &= ~RxINT_MASK;
        info->zs_channel->curregs[R1] |= (RxINT_ALL | TxINT_ENAB |
                                          EXT_INT_ENAB);
        info->zs_channel->curregs[R3] |= RxENABLE;
        info->zs_channel->curregs[R5] |= TxENAB;
        info->zs_channel->curregs[R15] |= (DCDIE | CTSIE | TxUIE | BRKIE);
        write_zsreg(info->zs_channel, R1, info->zs_channel->curregs[R1]);
        write_zsreg(info->zs_channel, R3, info->zs_channel->curregs[R3]);
        write_zsreg(info->zs_channel, R5, info->zs_channel->curregs[R5]);
        write_zsreg(info->zs_channel, R15, info->zs_channel->curregs[R15]);
 
        /*
         * And clear the interrupt registers again for luck.
         */
        write_zsreg(info->zs_channel, R0, ERR_RES);
        write_zsreg(info->zs_channel, R0, RES_H_IUS);
 
        /* Save the current value of RR0 */
        info->read_reg_zero = read_zsreg(info->zs_channel, R0);
 
        if (info->tty)
                clear_bit(TTY_IO_ERROR, &info->tty->flags);
        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
 
        info->flags |= ZILOG_INITIALIZED;
        restore_flags(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 dec_serial * info)
{
        unsigned long   flags;
 
        if (!(info->flags & ZILOG_INITIALIZED))
                return;
 
#ifdef SERIAL_DEBUG_OPEN
        printk("Shutting down serial port %d (irq %d)....", info->line,
               info->irq);
#endif
 
        save_flags(flags); cli(); /* Disable interrupts */
 
        if (info->xmit_buf) {
                free_page((unsigned long) info->xmit_buf);
                info->xmit_buf = 0;
        }
 
        info->zs_channel->curregs[1] = 0;
        write_zsreg(info->zs_channel, 1, info->zs_channel->curregs[1]); /* no interrupts */
 
        info->zs_channel->curregs[3] &= ~RxENABLE;
        write_zsreg(info->zs_channel, 3, info->zs_channel->curregs[3]);
 
        info->zs_channel->curregs[5] &= ~TxENAB;
        write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
        if (!info->tty || C_HUPCL(info->tty)) {
                zs_rtsdtr(info, RTS | DTR, 0);
        }
 
        if (info->tty)
                set_bit(TTY_IO_ERROR, &info->tty->flags);
 
        info->flags &= ~ZILOG_INITIALIZED;
        restore_flags(flags);
}
 
/*
 * 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 dec_serial *info)
{
        unsigned cflag;
        int     i;
        int     brg, bits;
        unsigned long flags;
 
        if (!info->hook) {
                if (!info->tty || !info->tty->termios)
                        return;
                cflag = info->tty->termios->c_cflag;
                if (!info->port)
                        return;
        } else {
                cflag = info->hook->cflags;
        }
 
        i = cflag & CBAUD;
        if (i & CBAUDEX) {
                i &= ~CBAUDEX;
                if (i < 1 || i > 2) {
                        if (!info->hook)
                                info->tty->termios->c_cflag &= ~CBAUDEX;
                        else
                                info->hook->cflags &= ~CBAUDEX;
                } else
                        i += 15;
        }
 
        save_flags(flags); cli();
        info->zs_baud = baud_table[i];
        if (info->zs_baud) {
                brg = BPS_TO_BRG(info->zs_baud, zs_parms->clock/info->clk_divisor);
                info->zs_channel->curregs[12] = (brg & 255);
                info->zs_channel->curregs[13] = ((brg >> 8) & 255);
                zs_rtsdtr(info, DTR, 1);
        } else {
                zs_rtsdtr(info, RTS | DTR, 0);
                return;
        }
 
        /* byte size and parity */
        info->zs_channel->curregs[3] &= ~RxNBITS_MASK;
        info->zs_channel->curregs[5] &= ~TxNBITS_MASK;
        switch (cflag & CSIZE) {
        case CS5:
                bits = 7;
                info->zs_channel->curregs[3] |= Rx5;
                info->zs_channel->curregs[5] |= Tx5;
                break;
        case CS6:
                bits = 8;
                info->zs_channel->curregs[3] |= Rx6;
                info->zs_channel->curregs[5] |= Tx6;
                break;
        case CS7:
                bits = 9;
                info->zs_channel->curregs[3] |= Rx7;
                info->zs_channel->curregs[5] |= Tx7;
                break;
        case CS8:
        default: /* defaults to 8 bits */
                bits = 10;
                info->zs_channel->curregs[3] |= Rx8;
                info->zs_channel->curregs[5] |= Tx8;
                break;
        }
 
        info->timeout = ((info->xmit_fifo_size*HZ*bits) / info->zs_baud);
        info->timeout += HZ/50;         /* Add .02 seconds of slop */
 
        info->zs_channel->curregs[4] &= ~(SB_MASK | PAR_ENA | PAR_EVEN);
        if (cflag & CSTOPB) {
                info->zs_channel->curregs[4] |= SB2;
        } else {
                info->zs_channel->curregs[4] |= SB1;
        }
        if (cflag & PARENB) {
                info->zs_channel->curregs[4] |= PAR_ENA;
        }
        if (!(cflag & PARODD)) {
                info->zs_channel->curregs[4] |= PAR_EVEN;
        }
 
        if (!(cflag & CLOCAL)) {
                if (!(info->zs_channel->curregs[15] & DCDIE))
                        info->read_reg_zero = read_zsreg(info->zs_channel, 0);
                info->zs_channel->curregs[15] |= DCDIE;
        } else
                info->zs_channel->curregs[15] &= ~DCDIE;
        if (cflag & CRTSCTS) {
                info->zs_channel->curregs[15] |= CTSIE;
                if ((read_zsreg(info->zs_channel, 0) & CTS) == 0)
                        info->tx_stopped = 1;
        } else {
                info->zs_channel->curregs[15] &= ~CTSIE;
                info->tx_stopped = 0;
        }
 
        /* Load up the new values */
        load_zsregs(info->zs_channel, info->zs_channel->curregs);
 
        restore_flags(flags);
}
 
static void rs_flush_chars(struct tty_struct *tty)
{
        struct dec_serial *info = (struct dec_serial *)tty->driver_data;
        unsigned long flags;
 
        if (serial_paranoia_check(info, tty->device, "rs_flush_chars"))
                return;
 
        if (info->xmit_cnt <= 0 || tty->stopped || info->tx_stopped ||
            !info->xmit_buf)
                return;
 
        /* Enable transmitter */
        save_flags(flags); cli();
        transmit_chars(info);
        restore_flags(flags);
}
 
static int rs_write(struct tty_struct * tty, int from_user,
                    const unsigned char *buf, int count)
{
        int     c, total = 0;
        struct dec_serial *info = (struct dec_serial *)tty->driver_data;
        unsigned long flags;
 
        if (serial_paranoia_check(info, tty->device, "rs_write"))
                return 0;
 
        if (!tty || !info->xmit_buf)
                return 0;
 
        save_flags(flags);
        while (1) {
                cli();
                c = MIN(count, MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
                                   SERIAL_XMIT_SIZE - info->xmit_head));
                if (c <= 0)
                        break;
 
                if (from_user) {
                        down(&tmp_buf_sem);
                        copy_from_user(tmp_buf, buf, c);
                        c = MIN(c, MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
                                       SERIAL_XMIT_SIZE - info->xmit_head));
                        memcpy(info->xmit_buf + info->xmit_head, tmp_buf, c);
                        up(&tmp_buf_sem);
                } else
                        memcpy(info->xmit_buf + info->xmit_head, buf, c);
                info->xmit_head = (info->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
                info->xmit_cnt += c;
                restore_flags(flags);
                buf += c;
                count -= c;
                total += c;
        }
 
        if (info->xmit_cnt && !tty->stopped && !info->tx_stopped
            && !info->tx_active)
                transmit_chars(info);
        restore_flags(flags);
        return total;
}
 
static int rs_write_room(struct tty_struct *tty)
{
        struct dec_serial *info = (struct dec_serial *)tty->driver_data;
        int     ret;
 
        if (serial_paranoia_check(info, tty->device, "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 dec_serial *info = (struct dec_serial *)tty->driver_data;
 
        if (serial_paranoia_check(info, tty->device, "rs_chars_in_buffer"))
                return 0;
        return info->xmit_cnt;
}
 
static void rs_flush_buffer(struct tty_struct *tty)
{
        struct dec_serial *info = (struct dec_serial *)tty->driver_data;
 
        if (serial_paranoia_check(info, tty->device, "rs_flush_buffer"))
                return;
        cli();
        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
        sti();
        wake_up_interruptible(&tty->write_wait);
        if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
            tty->ldisc.write_wakeup)
                (tty->ldisc.write_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 dec_serial *info = (struct dec_serial *)tty->driver_data;
        unsigned long flags;
 
#ifdef SERIAL_DEBUG_THROTTLE
        char    buf[64];
 
        printk("throttle %s: %d....\n", _tty_name(tty, buf),
               tty->ldisc.chars_in_buffer(tty));
#endif
 
        if (serial_paranoia_check(info, tty->device, "rs_throttle"))
                return;
 
        if (I_IXOFF(tty)) {
                save_flags(flags); cli();
                info->x_char = STOP_CHAR(tty);
                if (!info->tx_active)
                        transmit_chars(info);
                restore_flags(flags);
        }
 
        if (C_CRTSCTS(tty)) {
                zs_rtsdtr(info, RTS, 0);
        }
}
 
static void rs_unthrottle(struct tty_struct * tty)
{
        struct dec_serial *info = (struct dec_serial *)tty->driver_data;
        unsigned long flags;
 
#ifdef SERIAL_DEBUG_THROTTLE
        char    buf[64];
 
        printk("unthrottle %s: %d....\n", _tty_name(tty, buf),
               tty->ldisc.chars_in_buffer(tty));
#endif
 
        if (serial_paranoia_check(info, tty->device, "rs_unthrottle"))
                return;
 
        if (I_IXOFF(tty)) {
                save_flags(flags); cli();
                if (info->x_char)
                        info->x_char = 0;
                else {
                        info->x_char = START_CHAR(tty);
                        if (!info->tx_active)
                                transmit_chars(info);
                }
                restore_flags(flags);
        }
 
        if (C_CRTSCTS(tty)) {
                zs_rtsdtr(info, RTS, 1);
        }
}
 
/*
 * ------------------------------------------------------------
 * rs_ioctl() and friends
 * ------------------------------------------------------------
 */
 
static int get_serial_info(struct dec_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;
        return copy_to_user(retinfo,&tmp,sizeof(*retinfo));
}
 
static int set_serial_info(struct dec_serial * info,
                           struct serial_struct * new_info)
{
        struct serial_struct new_serial;
        struct dec_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 & ~ZILOG_USR_MASK) !=
                     (info->flags & ~ZILOG_USR_MASK)))
                        return -EPERM;
                info->flags = ((info->flags & ~ZILOG_USR_MASK) |
                               (new_serial.flags & ZILOG_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 & ~ZILOG_FLAGS) |
                        (new_serial.flags & ZILOG_FLAGS));
        info->type = new_serial.type;
        info->close_delay = new_serial.close_delay;
        info->closing_wait = new_serial.closing_wait;
 
check_and_exit:
        retval = zs_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 dec_serial * info, unsigned int *value)
{
        unsigned char status;
 
        cli();
        status = read_zsreg(info->zs_channel, 0);
        sti();
        put_user(status,value);
        return 0;
}
 
static int get_modem_info(struct dec_serial *info, unsigned int *value)
{
        unsigned char control, status_a, status_b;
        unsigned int result;
 
        if (info->zs_channel == info->zs_chan_a)
                result = 0;
        else {
                cli();
                control = info->zs_chan_a->curregs[5];
                status_a = read_zsreg(info->zs_chan_a, 0);
                status_b = read_zsreg(info->zs_channel, 0);
                sti();
                result =  ((control  & RTS) ? TIOCM_RTS: 0)
                        | ((control  & DTR) ? TIOCM_DTR: 0)
                        | ((status_b & DCD) ? TIOCM_CAR: 0)
                        | ((status_a & DCD) ? TIOCM_RNG: 0)
                        | ((status_a & SYNC_HUNT) ? TIOCM_DSR: 0)
                        | ((status_b & CTS) ? TIOCM_CTS: 0);
        }
        put_user(result, value);
        return 0;
}
 
static int set_modem_info(struct dec_serial *info, unsigned int cmd,
                          unsigned int *value)
{
        int error;
        unsigned int arg, bits;
 
        error = verify_area(VERIFY_READ, value, sizeof(int));
        if (error)
                return error;
 
        if (info->zs_channel == info->zs_chan_a)
                return 0;
 
        get_user(arg, value);
        bits = (arg & TIOCM_RTS? RTS: 0) + (arg & TIOCM_DTR? DTR: 0);
        cli();
        switch (cmd) {
        case TIOCMBIS:
                info->zs_chan_a->curregs[5] |= bits;
                break;
        case TIOCMBIC:
                info->zs_chan_a->curregs[5] &= ~bits;
                break;
        case TIOCMSET:
                info->zs_chan_a->curregs[5] =
                        (info->zs_chan_a->curregs[5] & ~(DTR | RTS)) | bits;
                break;
        default:
                sti();
                return -EINVAL;
        }
        write_zsreg(info->zs_chan_a, 5, info->zs_chan_a->curregs[5]);
        sti();
        return 0;
}
 
/*
 * rs_break - turn transmit break condition on/off
 */
static void rs_break(struct tty_struct *tty, int break_state)
{
        struct dec_serial *info = (struct dec_serial *) tty->driver_data;
        unsigned long flags;
 
        if (serial_paranoia_check(info, tty->device, "rs_break"))
                return;
        if (!info->port)
                return;
 
        save_flags(flags); cli();
        if (break_state == -1)
                info->zs_channel->curregs[5] |= SND_BRK;
        else
                info->zs_channel->curregs[5] &= ~SND_BRK;
        write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
        restore_flags(flags);
}
 
static int rs_ioctl(struct tty_struct *tty, struct file * file,
                    unsigned int cmd, unsigned long arg)
{
        int error;
        struct dec_serial * info = (struct dec_serial *)tty->driver_data;
 
        if (info->hook)
                return -ENODEV;
 
        if (serial_paranoia_check(info, tty->device, "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 TIOCMGET:
                        error = verify_area(VERIFY_WRITE, (void *) arg,
                                sizeof(unsigned int));
                        if (error)
                                return error;
                        return get_modem_info(info, (unsigned int *) arg);
                case TIOCMBIS:
                case TIOCMBIC:
                case TIOCMSET:
                        return set_modem_info(info, cmd, (unsigned int *) arg);
                case TIOCGSERIAL:
                        error = verify_area(VERIFY_WRITE, (void *) arg,
                                                sizeof(struct serial_struct));
                        if (error)
                                return error;
                        return get_serial_info(info,
                                               (struct serial_struct *) arg);
                case TIOCSSERIAL:
                        return set_serial_info(info,
                                               (struct serial_struct *) arg);
                case TIOCSERGETLSR: /* Get line status register */
                        error = verify_area(VERIFY_WRITE, (void *) arg,
                                sizeof(unsigned int));
                        if (error)
                                return error;
                        else
                            return get_lsr_info(info, (unsigned int *) arg);
 
                case TIOCSERGSTRUCT:
                        error = verify_area(VERIFY_WRITE, (void *) arg,
                                                sizeof(struct dec_serial));
                        if (error)
                                return error;
                        copy_from_user((struct dec_serial *) arg,
                                       info, sizeof(struct dec_serial));
                        return 0;
 
                default:
                        return -ENOIOCTLCMD;
                }
        return 0;
}
 
static void rs_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
        struct dec_serial *info = (struct dec_serial *)tty->driver_data;
        int was_stopped;
 
        if (tty->termios->c_cflag == old_termios->c_cflag)
                return;
        was_stopped = info->tx_stopped;
 
        change_speed(info);
 
        if (was_stopped && !info->tx_stopped)
                rs_start(tty);
}
 
/*
 * ------------------------------------------------------------
 * rs_close()
 *
 * This routine is called when the serial port gets closed.
 * Wait for the last remaining data to be sent.
 * ------------------------------------------------------------
 */
static void rs_close(struct tty_struct *tty, struct file * filp)
{
        struct dec_serial * info = (struct dec_serial *)tty->driver_data;
        unsigned long flags;
 
        if (!info || serial_paranoia_check(info, tty->device, "rs_close"))
                return;
 
        save_flags(flags); cli();
 
        if (tty_hung_up_p(filp)) {
                restore_flags(flags);
                return;
        }
 
#ifdef SERIAL_DEBUG_OPEN
        printk("rs_close ttyS%02d, count = %d\n", info->line, info->count);
#endif
        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%02d: %d\n",
                       info->line, info->count);
                info->count = 0;
        }
        if (info->count) {
                restore_flags(flags);
                return;
        }
        info->flags |= ZILOG_CLOSING;
        /*
         * Save the termios structure, since this port may have
         * separate termios for callout and dialin.
         */
        if (info->flags & ZILOG_NORMAL_ACTIVE)
                info->normal_termios = *tty->termios;
        if (info->flags & ZILOG_CALLOUT_ACTIVE)
                info->callout_termios = *tty->termios;
        /*
         * 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 != ZILOG_CLOSING_WAIT_NONE)
                tty_wait_until_sent(tty, info->closing_wait);
        /*
         * At this point we stop accepting input.  To do this, we
         * disable the receiver and receive interrupts.
         */
        info->zs_channel->curregs[3] &= ~RxENABLE;
        write_zsreg(info->zs_channel, 3, info->zs_channel->curregs[3]);
        info->zs_channel->curregs[1] = 0;        /* disable any rx ints */
        write_zsreg(info->zs_channel, 1, info->zs_channel->curregs[1]);
        ZS_CLEARFIFO(info->zs_channel);
        if (info->flags & ZILOG_INITIALIZED) {
                /*
                 * Before we drop DTR, make sure the SCC transmitter
                 * has completely drained.
                 */
                rs_wait_until_sent(tty, info->timeout);
        }
 
        shutdown(info);
        if (tty->driver.flush_buffer)
                tty->driver.flush_buffer(tty);
        if (tty->ldisc.flush_buffer)
                tty->ldisc.flush_buffer(tty);
        tty->closing = 0;
        info->event = 0;
        info->tty = 0;
        if (info->blocked_open) {
                if (info->close_delay) {
                        current->state = TASK_INTERRUPTIBLE;
                        schedule_timeout(info->close_delay);
                }
                wake_up_interruptible(&info->open_wait);
        }
        info->flags &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CALLOUT_ACTIVE|
                         ZILOG_CLOSING);
        wake_up_interruptible(&info->close_wait);
        restore_flags(flags);
}
 
/*
 * rs_wait_until_sent() --- wait until the transmitter is empty
 */
static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
{
        struct dec_serial *info = (struct dec_serial *) tty->driver_data;
        unsigned long orig_jiffies, char_time;
 
        if (serial_paranoia_check(info, tty->device, "rs_wait_until_sent"))
                return;
 
        orig_jiffies = jiffies;
        /*
         * Set the check interval to be 1/5 of the estimated time to
         * send a single character, and make it at least 1.  The check
         * interval should also be less than the timeout.
         */
        char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
        char_time = char_time / 5;
        if (char_time == 0)
                char_time = 1;
        if (timeout)
                char_time = MIN(char_time, timeout);
        while ((read_zsreg(info->zs_channel, 1) & Tx_BUF_EMP) == 0) {
                current->state = TASK_INTERRUPTIBLE;
                schedule_timeout(char_time);
                if (signal_pending(current))
                        break;
                if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;
        }
        current->state = TASK_RUNNING;
}
 
/*
 * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
void rs_hangup(struct tty_struct *tty)
{
        struct dec_serial * info = (struct dec_serial *)tty->driver_data;
 
        if (serial_paranoia_check(info, tty->device, "rs_hangup"))
                return;
 
        rs_flush_buffer(tty);
        shutdown(info);
        info->event = 0;
        info->count = 0;
        info->flags &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CALLOUT_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 dec_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 & ZILOG_CLOSING) {
                interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
                return ((info->flags & ZILOG_HUP_NOTIFY) ?
                        -EAGAIN : -ERESTARTSYS);
#else
                return -EAGAIN;
#endif
        }
 
        /*
         * If this is a callout device, then just make sure the normal
         * device isn't being used.
         */
        if (tty->driver.subtype == SERIAL_TYPE_CALLOUT) {
                if (info->flags & ZILOG_NORMAL_ACTIVE)
                        return -EBUSY;
                if ((info->flags & ZILOG_CALLOUT_ACTIVE) &&
                    (info->flags & ZILOG_SESSION_LOCKOUT) &&
                    (info->session != current->session))
                    return -EBUSY;
                if ((info->flags & ZILOG_CALLOUT_ACTIVE) &&
                    (info->flags & ZILOG_PGRP_LOCKOUT) &&
                    (info->pgrp != current->pgrp))
                    return -EBUSY;
                info->flags |= ZILOG_CALLOUT_ACTIVE;
                return 0;
        }
 
        /*
         * 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))) {
                if (info->flags & ZILOG_CALLOUT_ACTIVE)
                        return -EBUSY;
                info->flags |= ZILOG_NORMAL_ACTIVE;
                return 0;
        }
 
        if (info->flags & ZILOG_CALLOUT_ACTIVE) {
                if (info->normal_termios.c_cflag & CLOCAL)
                        do_clocal = 1;
        } else {
                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);
#ifdef SERIAL_DEBUG_OPEN
        printk("block_til_ready before block: ttyS%02d, count = %d\n",
               info->line, info->count);
#endif
        cli();
        if (!tty_hung_up_p(filp))
                info->count--;
        sti();
        info->blocked_open++;
        while (1) {
                cli();
                if (!(info->flags & ZILOG_CALLOUT_ACTIVE) &&
                    (tty->termios->c_cflag & CBAUD))
                        zs_rtsdtr(info, RTS | DTR, 1);
                sti();
                set_current_state(TASK_INTERRUPTIBLE);
                if (tty_hung_up_p(filp) ||
                    !(info->flags & ZILOG_INITIALIZED)) {
#ifdef SERIAL_DO_RESTART
                        if (info->flags & ZILOG_HUP_NOTIFY)
                                retval = -EAGAIN;
                        else
                                retval = -ERESTARTSYS;
#else
                        retval = -EAGAIN;
#endif
                        break;
                }
                if (!(info->flags & ZILOG_CALLOUT_ACTIVE) &&
                    !(info->flags & ZILOG_CLOSING) &&
                    (do_clocal || (read_zsreg(info->zs_channel, 0) & DCD)))
                        break;
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;
                        break;
                }
#ifdef SERIAL_DEBUG_OPEN
                printk("block_til_ready blocking: ttyS%02d, count = %d\n",
                       info->line, info->count);
#endif
                schedule();
        }
        current->state = TASK_RUNNING;
        remove_wait_queue(&info->open_wait, &wait);
        if (!tty_hung_up_p(filp))
                info->count++;
        info->blocked_open--;
#ifdef SERIAL_DEBUG_OPEN
        printk("block_til_ready after blocking: ttyS%02d, count = %d\n",
               info->line, info->count);
#endif
        if (retval)
                return retval;
        info->flags |= ZILOG_NORMAL_ACTIVE;
        return 0;
}
 
/*
 * This routine is called whenever a serial port is opened.  It
 * enables interrupts for a serial port, linking in its ZILOG 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 dec_serial       *info;
        int                     retval, line;
 
        line = MINOR(tty->device) - tty->driver.minor_start;
        if ((line < 0) || (line >= zs_channels_found))
                return -ENODEV;
        info = zs_soft + line;
 
        if (info->hook)
                return -ENODEV;
 
        if (serial_paranoia_check(info, tty->device, "rs_open"))
                return -ENODEV;
#ifdef SERIAL_DEBUG_OPEN
        printk("rs_open %s%d, count = %d\n", tty->driver.name, info->line,
               info->count);
#endif
 
        info->count++;
        tty->driver_data = info;
        info->tty = tty;
 
        /*
         * If the port is the middle of closing, bail out now
         */
        if (tty_hung_up_p(filp) ||
            (info->flags & ZILOG_CLOSING)) {
                if (info->flags & ZILOG_CLOSING)
                        interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
                return ((info->flags & ZILOG_HUP_NOTIFY) ?
                        -EAGAIN : -ERESTARTSYS);
#else
                return -EAGAIN;
#endif
        }
 
        /*
         * Start up serial port
         */
        retval = zs_startup(info);
        if (retval)
                return retval;
 
        retval = block_til_ready(tty, filp, info);
        if (retval) {
#ifdef SERIAL_DEBUG_OPEN
                printk("rs_open returning after block_til_ready with %d\n",
                       retval);
#endif
                return retval;
        }
 
        if ((info->count == 1) && (info->flags & ZILOG_SPLIT_TERMIOS)) {
                if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
                        *tty->termios = info->normal_termios;
                else
                        *tty->termios = info->callout_termios;
                change_speed(info);
        }
#ifdef CONFIG_SERIAL_DEC_CONSOLE
        if (sercons.cflag && sercons.index == line) {
                tty->termios->c_cflag = sercons.cflag;
                sercons.cflag = 0;
                change_speed(info);
        }
#endif
 
        info->session = current->session;
        info->pgrp = current->pgrp;
 
#ifdef SERIAL_DEBUG_OPEN
        printk("rs_open ttyS%02d successful...", info->line);
#endif
/* tty->low_latency = 1; */
        return 0;
}
 
/* Finally, routines used to initialize the serial driver. */
 
static void __init show_serial_version(void)
{
        printk("DECstation Z8530 serial driver version 0.08\n");
}
 
/*  Initialize Z8530s zs_channels
 */
 
static void __init probe_sccs(void)
{
        struct dec_serial **pp;
        int i, n, n_chips = 0, n_channels, chip, channel;
        unsigned long flags;
 
        /*
         * did we get here by accident?
         */
        if(!BUS_PRESENT) {
                printk("Not on JUNKIO machine, skipping probe_sccs\n");
                return;
        }
 
        /*
         * When serial console is activated, tc_init has not been called yet
         * and system_base is undefined. Unfortunately we have to hardcode
         * system_base for this case :-(. HK
         */
        switch(mips_machtype) {
#ifdef CONFIG_DECSTATION
        case MACH_DS5000_2X0:
        case MACH_DS5900:
                system_base = KSEG1ADDR(0x1f800000);
                n_chips = 2;
                zs_parms = &ds_parms;
                zs_parms->irq0 = dec_interrupt[DEC_IRQ_SCC0];
                zs_parms->irq1 = dec_interrupt[DEC_IRQ_SCC1];
                break;
        case MACH_DS5000_1XX:
                system_base = KSEG1ADDR(0x1c000000);
                n_chips = 2;
                zs_parms = &ds_parms;
                zs_parms->irq0 = dec_interrupt[DEC_IRQ_SCC0];
                zs_parms->irq1 = dec_interrupt[DEC_IRQ_SCC1];
                break;
        case MACH_DS5000_XX:
                system_base = KSEG1ADDR(0x1c000000);
                n_chips = 1;
                zs_parms = &ds_parms;
                zs_parms->irq0 = dec_interrupt[DEC_IRQ_SCC0];
                break;
#endif
#ifdef CONFIG_BAGET_MIPS
        case MACH_BAGET202:
                system_base = UNI_IO_BASE;
                n_chips = 2;
                zs_parms = &baget_parms;
                zs_init_regs[2] = 0x8;
                break;
#endif
        default:
                panic("zs: unsupported bus");
        }
        if (!zs_parms)
                panic("zs: uninitialized parms");
 
        pp = &zs_chain;
 
        n_channels = 0;
 
        for (chip = 0; chip < n_chips; chip++) {
                for (channel = 0; channel <= 1; channel++) {
                        /*
                         * The sccs reside on the high byte of the 16 bit IOBUS
                         */
                        zs_channels[n_channels].control =
                                (volatile unsigned char *)system_base +
                          (0 == chip ? zs_parms->scc0 : zs_parms->scc1) +
                          (0 == channel ? zs_parms->channel_a_offset :
                                          zs_parms->channel_b_offset);
                        zs_channels[n_channels].data =
                                zs_channels[n_channels].control + 4;
 
#ifndef CONFIG_SERIAL_DEC_CONSOLE
                        /*
                         * We're called early and memory managment isn't up, yet.
                         * Thus check_region would fail.
                         */
                        if (check_region((unsigned long)
                                         zs_channels[n_channels].control,
                                         ZS_CHAN_IO_SIZE) < 0) {
                                panic("SCC I/O region is not free");
                        }
                        request_region((unsigned long)
                                       zs_channels[n_channels].control,
                                       ZS_CHAN_IO_SIZE, "SCC");
#endif
                        zs_soft[n_channels].zs_channel = &zs_channels[n_channels];
                        /* HACK alert! */
                        if (!(chip & 1))
                                zs_soft[n_channels].irq = zs_parms->irq0;
                        else
                                zs_soft[n_channels].irq = zs_parms->irq1;
 
                        /*
                         *  Identification of channel A. Location of channel A
                         *  inside chip depends on mapping of internal address
                         *  the chip decodes channels by.
                         *  CHANNEL_A_NR returns either 0 (in case of
                         *  DECstations) or 1 (in case of Baget).
                         */
                        if (CHANNEL_A_NR == channel)
                                zs_soft[n_channels].zs_chan_a =
                                    &zs_channels[n_channels+1-2*CHANNEL_A_NR];
                        else
                                zs_soft[n_channels].zs_chan_a =
                                    &zs_channels[n_channels];
 
                        *pp = &zs_soft[n_channels];
                        pp = &zs_soft[n_channels].zs_next;
                        n_channels++;
                }
        }
 
        *pp = 0;
        zs_channels_found = n_channels;
 
        for (n = 0; n < zs_channels_found; n++) {
                for (i = 0; i < 16; i++) {
                        zs_soft[n].zs_channel->curregs[i] = zs_init_regs[i];
                }
        }
 
        save_and_cli(flags);
        for (n = 0; n < zs_channels_found; n++) {
                if (n % 2 == 0) {
                        write_zsreg(zs_soft[n].zs_chan_a, R9, FHWRES);
                        udelay(10);
                        write_zsreg(zs_soft[n].zs_chan_a, R9, 0);
                }
                load_zsregs(zs_soft[n].zs_channel,
                            zs_soft[n].zs_channel->curregs);
        }
        restore_flags(flags);
}
 
/* zs_init inits the driver */
int __init zs_init(void)
{
        int channel, i;
        struct dec_serial *info;
 
        if(!BUS_PRESENT)
                return -ENODEV;
 
        /* Setup base handler, and timer table. */
        init_bh(SERIAL_BH, do_serial_bh);
 
        /* Find out how many Z8530 SCCs we have */
        if (zs_chain == 0)
                probe_sccs();
 
        show_serial_version();
 
        /* Initialize the tty_driver structure */
        /* Not all of this is exactly right for us. */
 
        memset(&serial_driver, 0, sizeof(struct tty_driver));
        serial_driver.magic = TTY_DRIVER_MAGIC;
#if (LINUX_VERSION_CODE > 0x2032D && defined(CONFIG_DEVFS_FS))
        serial_driver.name = "tts/%d";
#else
        serial_driver.name = "ttyS";
#endif
        serial_driver.major = TTY_MAJOR;
        serial_driver.minor_start = 64;
        serial_driver.num = zs_channels_found;
        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 =
                B9600 | CS8 | CREAD | HUPCL | CLOCAL;
        serial_driver.flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
        serial_driver.refcount = &serial_refcount;
        serial_driver.table = serial_table;
        serial_driver.termios = serial_termios;
        serial_driver.termios_locked = serial_termios_locked;
 
        serial_driver.open = rs_open;
        serial_driver.close = rs_close;
        serial_driver.write = rs_write;
        serial_driver.flush_chars = rs_flush_chars;
        serial_driver.write_room = rs_write_room;
        serial_driver.chars_in_buffer = rs_chars_in_buffer;
        serial_driver.flush_buffer = rs_flush_buffer;
        serial_driver.ioctl = rs_ioctl;
        serial_driver.throttle = rs_throttle;
        serial_driver.unthrottle = rs_unthrottle;
        serial_driver.set_termios = rs_set_termios;
        serial_driver.stop = rs_stop;
        serial_driver.start = rs_start;
        serial_driver.hangup = rs_hangup;
        serial_driver.break_ctl = rs_break;
        serial_driver.wait_until_sent = rs_wait_until_sent;
 
        /*
         * The callout device is just like normal device except for
         * major number and the subtype code.
         */
        callout_driver = serial_driver;
#if (LINUX_VERSION_CODE > 0x2032D && defined(CONFIG_DEVFS_FS))
        callout_driver.name = "cua/%d";
#else
        callout_driver.name = "cua";
#endif
        callout_driver.major = TTYAUX_MAJOR;
        callout_driver.subtype = SERIAL_TYPE_CALLOUT;
 
        if (tty_register_driver(&serial_driver))
                panic("Couldn't register serial driver");
        if (tty_register_driver(&callout_driver))
                panic("Couldn't register callout driver");
 
        for (info = zs_chain, i = 0; info; info = info->zs_next, i++) {
 
                /* Needed before interrupts are enabled. */
                info->tty = 0;
                info->x_char = 0;
 
                if (info->hook && info->hook->init_info) {
                        (*info->hook->init_info)(info);
                        continue;
                }
 
                info->magic = SERIAL_MAGIC;
                info->port = (int) info->zs_channel->control;
                info->line = i;
                info->custom_divisor = 16;
                info->close_delay = 50;
                info->closing_wait = 3000;
                info->event = 0;
                info->count = 0;
                info->blocked_open = 0;
                info->tqueue.routine = do_softint;
                info->tqueue.data = info;
                info->callout_termios = callout_driver.init_termios;
                info->normal_termios = serial_driver.init_termios;
                init_waitqueue_head(&info->open_wait);
                init_waitqueue_head(&info->close_wait);
                printk("ttyS%02d at 0x%08x (irq = %d) is a Z85C30 SCC\n",
                       info->line, info->port, info->irq);
                tty_register_devfs(&serial_driver, 0,
                                   serial_driver.minor_start + info->line);
                tty_register_devfs(&callout_driver, 0,
                                   callout_driver.minor_start + info->line);
 
        }
 
        for (channel = 0; channel < zs_channels_found; ++channel) {
                zs_soft[channel].clk_divisor = 16;
                zs_soft[channel].zs_baud = get_zsbaud(&zs_soft[channel]);
 
                if (request_irq(zs_soft[channel].irq, rs_interrupt, SA_SHIRQ,
                                "scc", &zs_soft[channel]))
                        printk(KERN_ERR "decserial: can't get irq %d\n",
                               zs_soft[channel].irq);
 
                if (zs_soft[channel].hook) {
                        zs_startup(&zs_soft[channel]);
                        if (zs_soft[channel].hook->init_channel)
                                (*zs_soft[channel].hook->init_channel)
                                        (&zs_soft[channel]);
                }
        }
 
        return 0;
}
 
/*
 * polling I/O routines
 */
static int
zs_poll_tx_char(struct dec_serial *info, unsigned char ch)
{
        struct dec_zschannel *chan = info->zs_channel;
        int    ret;
 
        if(chan) {
                int loops = 10000;
 
                while (loops && !(read_zsreg(chan, 0) & Tx_BUF_EMP))
                        loops--;
 
                if (loops) {
                        write_zsdata(chan, ch);
                        ret = 0;
                } else
                        ret = -EAGAIN;
 
                return ret;
        } else
                return -ENODEV;
}
 
static int
zs_poll_rx_char(struct dec_serial *info)
{
        struct dec_zschannel *chan = info->zs_channel;
        int    ret;
 
        if(chan) {
                int loops = 10000;
 
                while (loops && !(read_zsreg(chan, 0) & Rx_CH_AV))
                        loops--;
 
                if (loops)
                        ret = read_zsdata(chan);
                else
                        ret = -EAGAIN;
 
                return ret;
        } else
                return -ENODEV;
}
 
unsigned int register_zs_hook(unsigned int channel, struct zs_hook *hook)
{
        struct dec_serial *info = &zs_soft[channel];
 
        if (info->hook) {
                printk(__FUNCTION__": line %d has already a hook registered\n", channel);
 
                return 0;
        } else {
                hook->poll_rx_char = zs_poll_rx_char;
                hook->poll_tx_char = zs_poll_tx_char;
                info->hook = hook;
 
                return 1;
        }
}
 
unsigned int unregister_zs_hook(unsigned int channel)
{
        struct dec_serial *info = &zs_soft[channel];
 
        if (info->hook) {
                info->hook = NULL;
                return 1;
        } else {
                printk(__FUNCTION__": trying to unregister hook on line %d,"
                       " but none is registered\n", channel);
                return 0;
        }
}
 
/*
 * ------------------------------------------------------------
 * Serial console driver
 * ------------------------------------------------------------
 */
#ifdef CONFIG_SERIAL_DEC_CONSOLE
 
 
/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 */
static void serial_console_write(struct console *co, const char *s,
                                 unsigned count)
{
        struct dec_serial *info;
        int i;
 
        info = zs_soft + co->index;
 
        for (i = 0; i < count; i++, s++) {
                if(*s == '\n')
                        zs_poll_tx_char(info, '\r');
                zs_poll_tx_char(info, *s);
        }
}
 
static kdev_t serial_console_device(struct console *c)
{
        return MKDEV(TTY_MAJOR, 64 + c->index);
}
 
/*
 *      Setup initial baud/bits/parity. We do two things here:
 *      - construct a cflag setting for the first rs_open()
 *      - initialize the serial port
 *      Return non-zero if we didn't find a serial port.
 */
static int __init serial_console_setup(struct console *co, char *options)
{
        struct dec_serial *info;
        int baud = 9600;
        int bits = 8;
        int parity = 'n';
        int cflag = CREAD | HUPCL | CLOCAL;
        int clk_divisor = 16;
        int brg;
        char *s;
        unsigned long flags;
 
        if(!BUS_PRESENT)
                return -ENODEV;
 
        info = zs_soft + co->index;
 
        if (zs_chain == 0)
                probe_sccs();
 
        info->is_cons = 1;
 
        if (options) {
                baud = simple_strtoul(options, NULL, 10);
                s = options;
                while(*s >= '0' && *s <= '9')
                        s++;
                if (*s)
                        parity = *s++;
                if (*s)
                        bits   = *s - '0';
        }
 
        /*
         *      Now construct a cflag setting.
         */
        switch(baud) {
        case 1200:
                cflag |= B1200;
                break;
        case 2400:
                cflag |= B2400;
                break;
        case 4800:
                cflag |= B4800;
                break;
        case 19200:
                cflag |= B19200;
                break;
        case 38400:
                cflag |= B38400;
                break;
        case 57600:
                cflag |= B57600;
                break;
        case 115200:
                cflag |= B115200;
                break;
        case 9600:
        default:
                cflag |= B9600;
                /*
                 * Set this to a sane value to prevent a divide error.
                 */
                baud  = 9600;
                break;
        }
        switch(bits) {
        case 7:
                cflag |= CS7;
                break;
        default:
        case 8:
                cflag |= CS8;
                break;
        }
        switch(parity) {
        case 'o': case 'O':
                cflag |= PARODD;
                break;
        case 'e': case 'E':
                cflag |= PARENB;
                break;
        }
        co->cflag = cflag;
 
        save_and_cli(flags);
 
        /*
         * Set up the baud rate generator.
         */
        brg = BPS_TO_BRG(baud, zs_parms->clock / clk_divisor);
        info->zs_channel->curregs[R12] = (brg & 255);
        info->zs_channel->curregs[R13] = ((brg >> 8) & 255);
 
        /*
         * Set byte size and parity.
         */
        if (bits == 7) {
                info->zs_channel->curregs[R3] |= Rx7;
                info->zs_channel->curregs[R5] |= Tx7;
        } else {
                info->zs_channel->curregs[R3] |= Rx8;
                info->zs_channel->curregs[R5] |= Tx8;
        }
        if (cflag & PARENB) {
                info->zs_channel->curregs[R4] |= PAR_ENA;
        }
        if (!(cflag & PARODD)) {
                info->zs_channel->curregs[R4] |= PAR_EVEN;
        }
        info->zs_channel->curregs[R4] |= SB1;
 
        /*
         * Turn on RTS and DTR.
         */
        zs_rtsdtr(info, RTS | DTR, 1);
 
        /*
         * Finally, enable sequencing.
         */
        info->zs_channel->curregs[R3] |= RxENABLE;
        info->zs_channel->curregs[R5] |= TxENAB;
 
        /*
         * Clear the interrupt registers.
         */
        write_zsreg(info->zs_channel, R0, ERR_RES);
        write_zsreg(info->zs_channel, R0, RES_H_IUS);
 
        /*
         * Load up the new values.
         */
        load_zsregs(info->zs_channel, info->zs_channel->curregs);
 
        /* Save the current value of RR0 */
        info->read_reg_zero = read_zsreg(info->zs_channel, R0);
 
        zs_soft[co->index].clk_divisor = clk_divisor;
        zs_soft[co->index].zs_baud = get_zsbaud(&zs_soft[co->index]);
 
        restore_flags(flags);
 
        return 0;
}
 
static struct console sercons = {
        .name           = "ttyS",
        .write          = serial_console_write,
        .device         = serial_console_device,
        .setup          = serial_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
};
 
/*
 *      Register console.
 */
void __init zs_serial_console_init(void)
{
        register_console(&sercons);
}
#endif /* ifdef CONFIG_SERIAL_DEC_CONSOLE */
 
#ifdef CONFIG_KGDB
struct dec_zschannel *zs_kgdbchan;
static unsigned char scc_inittab[] = {
        9,  0x80,       /* reset A side (CHRA) */
        13, 0,           /* set baud rate divisor */
        12, 1,
        14, 1,          /* baud rate gen enable, src=rtxc (BRENABL) */
        11, 0x50,       /* clocks = br gen (RCBR | TCBR) */
        5,  0x6a,       /* tx 8 bits, assert RTS (Tx8 | TxENAB | RTS) */
        4,  0x44,       /* x16 clock, 1 stop (SB1 | X16CLK)*/
        3,  0xc1,       /* rx enable, 8 bits (RxENABLE | Rx8)*/
};
 
/* These are for receiving and sending characters under the kgdb
 * source level kernel debugger.
 */
void putDebugChar(char kgdb_char)
{
        struct dec_zschannel *chan = zs_kgdbchan;
        while ((read_zsreg(chan, 0) & Tx_BUF_EMP) == 0)
                RECOVERY_DELAY;
        write_zsdata(chan, kgdb_char);
}
char getDebugChar(void)
{
        struct dec_zschannel *chan = zs_kgdbchan;
        while((read_zsreg(chan, 0) & Rx_CH_AV) == 0)
                eieio(); /*barrier();*/
        return read_zsdata(chan);
}
void kgdb_interruptible(int yes)
{
        struct dec_zschannel *chan = zs_kgdbchan;
        int one, nine;
        nine = read_zsreg(chan, 9);
        if (yes == 1) {
                one = EXT_INT_ENAB|RxINT_ALL;
                nine |= MIE;
                printk("turning serial ints on\n");
        } else {
                one = RxINT_DISAB;
                nine &= ~MIE;
                printk("turning serial ints off\n");
        }
        write_zsreg(chan, 1, one);
        write_zsreg(chan, 9, nine);
}
 
static int kgdbhook_init_channel(struct dec_serial* info)
{
        return 0;
}
 
static void kgdbhook_init_info(struct dec_serial* info)
{
}
 
static void kgdbhook_rx_char(struct dec_serial* info,
                             unsigned char ch, unsigned char stat)
{
        if (ch == 0x03 || ch == '$')
                breakpoint();
        if (stat & (Rx_OVR|FRM_ERR|PAR_ERR))
                write_zsreg(info->zs_channel, 0, ERR_RES);
}
 
/* This sets up the serial port we're using, and turns on
 * interrupts for that channel, so kgdb is usable once we're done.
 */
static inline void kgdb_chaninit(struct dec_zschannel *ms, int intson, int bps)
{
        int brg;
        int i, x;
        volatile char *sccc = ms->control;
        brg = BPS_TO_BRG(bps, zs_parms->clock/16);
        printk("setting bps on kgdb line to %d [brg=%x]\n", bps, brg);
        for (i = 20000; i != 0; --i) {
                x = *sccc; eieio();
        }
        for (i = 0; i < sizeof(scc_inittab); ++i) {
                write_zsreg(ms, scc_inittab[i], scc_inittab[i+1]);
                i++;
        }
}
/* This is called at boot time to prime the kgdb serial debugging
 * serial line.  The 'tty_num' argument is 0 for /dev/ttya and 1
 * for /dev/ttyb which is determined in setup_arch() from the
 * boot command line flags.
 */
struct zs_hook zs_kgdbhook = {
        init_channel : kgdbhook_init_channel,
        init_info    : kgdbhook_init_info,
        cflags       : B38400|CS8|CLOCAL,
        rx_char      : kgdbhook_rx_char,
}
 
void __init zs_kgdb_hook(int tty_num)
{
        /* Find out how many Z8530 SCCs we have */
        if (zs_chain == 0)
                probe_sccs();
        zs_soft[tty_num].zs_channel = &zs_channels[tty_num];
        zs_kgdbchan = zs_soft[tty_num].zs_channel;
        zs_soft[tty_num].change_needed = 0;
        zs_soft[tty_num].clk_divisor = 16;
        zs_soft[tty_num].zs_baud = 38400;
        zs_soft[tty_num].hook = &zs_kgdbhook; /* This runs kgdb */
        /* Turn on transmitter/receiver at 8-bits/char */
        kgdb_chaninit(zs_soft[tty_num].zs_channel, 1, 38400);
        printk("KGDB: on channel %d initialized\n", tty_num);
        set_debug_traps(); /* init stub */
}
#endif /* ifdef CONFIG_KGDB */
 
 
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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [drivers/] [tc/] [zs.c] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	1275	phoenix	`/*`
2			`* decserial.c: Serial port driver for IOASIC DECstations.`
3			`*`
4			`* Derived from drivers/sbus/char/sunserial.c by Paul Mackerras.`
5			`* Derived from drivers/macintosh/macserial.c by Harald Koerfgen.`
6			`*`
7			`* DECstation changes`
8			`* Copyright (C) 1998-2000 Harald Koerfgen`
9			`* Copyright (C) 2000, 2001, 2002, 2003, 2004 Maciej W. Rozycki`
10			`*`
11			`* For the rest of the code the original Copyright applies:`
12			`* Copyright (C) 1996 Paul Mackerras (Paul.Mackerras@cs.anu.edu.au)`
13			`* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)`
14			`*`
15			`*`
16			`* Note: for IOASIC systems the wiring is as follows:`
17			`*`
18			`* mouse/keyboard:`
19			`* DIN-7 MJ-4 signal SCC`
20			`* 2 1 TxD <- A.TxD`
21			`* 3 4 RxD -> A.RxD`
22			`*`
23			`* EIA-232/EIA-423:`
24			`* DB-25 MMJ-6 signal SCC`
25			`* 2 2 TxD <- B.TxD`
26			`* 3 5 RxD -> B.RxD`
27			`* 4 RTS <- ~A.RTS`
28			`* 5 CTS -> ~B.CTS`
29			`* 6 6 DSR -> ~A.SYNC`
30			`* 8 CD -> ~B.DCD`
31			`* 12 DSRS(DCE) -> ~A.CTS (*)`
32			`* 15 TxC -> B.TxC`
33			`* 17 RxC -> B.RxC`
34			`* 20 1 DTR <- ~A.DTR`
35			`* 22 RI -> ~A.DCD`
36			`* 23 DSRS(DTE) <- ~B.RTS`
37			`*`
38			`* (*) EIA-232 defines the signal at this pin to be SCD, while DSRS(DCE)`
39			`* is shared with DSRS(DTE) at pin 23.`
40			`*/`