Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2253 insertions, 0 deletions

diff --git a/drivers/tc/zs.c b/drivers/tc/zs.c
new file mode 100644
index 00000000000..4382ee60b6a
--- /dev/null
+++ b/drivers/tc/zs.c
@@ -0,0 +1,2253 @@
+/*
+ * 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/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/uaccess.h>
+#include <asm/bootinfo.h>
+#include <asm/dec/serial.h>
+
+#ifdef CONFIG_MACH_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_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_MACH_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_MACH_DECSTATION
+#define DS_BUS_PRESENT (IOASIC)
+#else
+#define DS_BUS_PRESENT 0
+#endif
+
+#define BUS_PRESENT (DS_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 */
+	0				/* write 15 */
+};
+
+DECLARE_TASK_QUEUE(tq_zs_serial);
+
+static 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.
+ */
+#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);
+
+/*
+ * 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,
+					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 mac_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 };
+
+/*
+ * 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
+ * -----------------------------------------------------------------------
+ */
+
+/*
+ * 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;
+
+		flag = TTY_NORMAL;
+		if (info->tty_break) {
+			info->tty_break = 0;
+			flag = TTY_BREAK;
+			if (info->flags & ZILOG_SAK)
+				do_SAK(tty);
+			/* Ignore the null char got when BREAK is removed.  */
+			if (ch == 0)
+				continue;
+		} else {
+			if (stat & Rx_OVR) {
+				flag = TTY_OVERRUN;
+			} else if (stat & FRM_ERR) {
+				flag = TTY_FRAME;
+			} else if (stat & PAR_ERR) {
+				flag = TTY_PARITY;
+			}
+			if (flag != TTY_NORMAL)
+				/* 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) {
+			/* Ignore the null char got when BREAK is removed.  */
+			if (ch == 0)
+				continue;
+			if (time_before(jiffies, break_pressed + HZ * 5)) {
+				handle_sysrq(ch, regs, NULL);
+				break_pressed = 0;
+				continue;
+			}
+			break_pressed = 0;
+		}
+#endif
+
+		if (info->hook && info->hook->rx_char) {
+			(*info->hook->rx_char)(ch, flag);
+			return;
+  		}
+
+		tty_insert_flip_char(tty, ch, flag);
+	}
+	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) && !(info->read_reg_zero & BRK_ABRT)) {
+#if defined(CONFIG_SERIAL_DEC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) && \
+   !defined(MODULE)
+		if (info->line == sercons.index) {
+			if (!break_pressed)
+				break_pressed = jiffies;
+		} else
+#endif
+			info->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 {
+				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->name, "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->name, "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)) {
+		tty_wakeup(tty);
+	}
+}
+
+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_zeroed_page(GFP_KERNEL);
+		if (!info->xmit_buf)
+			return -ENOMEM;
+	}
+
+	save_flags(flags); cli();
+
+#ifdef SERIAL_DEBUG_OPEN
+	printk("starting up ttyS%d (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->name, "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,
+		    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->name, "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->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 dec_serial *info = (struct dec_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 dec_serial *info = (struct dec_serial *)tty->driver_data;
+
+	if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
+		return;
+	cli();
+	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
+	sti();
+	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 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->name, "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->name, "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)) ? -EFAULT : 0;
+}
+
+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 rs_tiocmget(struct tty_struct *tty, struct file *file)
+{
+	struct dec_serial * info = (struct dec_serial *)tty->driver_data;
+	unsigned char control, status_a, status_b;
+	unsigned int result;
+
+	if (info->hook)
+		return -ENODEV;
+
+	if (serial_paranoia_check(info, tty->name, __FUNCTION__))
+		return -ENODEV;
+
+	if (tty->flags & (1 << TTY_IO_ERROR))
+		return -EIO;
+
+	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);
+	}
+	return result;
+}
+
+static int rs_tiocmset(struct tty_struct *tty, struct file *file,
+                       unsigned int set, unsigned int clear)
+{
+	struct dec_serial * info = (struct dec_serial *)tty->driver_data;
+	int error;
+	unsigned int arg, bits;
+
+	if (info->hook)
+		return -ENODEV;
+
+	if (serial_paranoia_check(info, tty->name, __FUNCTION__))
+		return -ENODEV;
+
+	if (tty->flags & (1 << TTY_IO_ERROR))
+		return -EIO;
+
+	if (info->zs_channel == info->zs_chan_a)
+		return 0;
+
+	get_user(arg, value);
+	cli();
+	if (set & TIOCM_RTS)
+		info->zs_chan_a->curregs[5] |= RTS;
+	if (set & TIOCM_DTR)
+		info->zs_chan_a->curregs[5] |= DTR;
+	if (clear & TIOCM_RTS)
+		info->zs_chan_a->curregs[5] &= ~RTS;
+	if (clear & TIOCM_DTR)
+		info->zs_chan_a->curregs[5] &= ~DTR;
+	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->name, "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->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 TIOCGSERIAL:
+		if (!access_ok(VERIFY_WRITE, (void *)arg,
+			       sizeof(struct serial_struct)))
+			return -EFAULT;
+		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 */
+		if (!access_ok(VERIFY_WRITE, (void *)arg,
+			       sizeof(unsigned int)))
+			return -EFAULT;
+		return get_lsr_info(info, (unsigned int *)arg);
+
+	case TIOCSERGSTRUCT:
+		if (!access_ok(VERIFY_WRITE, (void *)arg,
+			       sizeof(struct dec_serial)))
+			return -EFAULT;
+		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->name, "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%d, 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%d: %d\n",
+		       info->line, info->count);
+		info->count = 0;
+	}
+	if (info->count) {
+		restore_flags(flags);
+		return;
+	}
+	info->flags |= ZILOG_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 != 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);
+	tty_ldisc_flush(tty);
+	tty->closing = 0;
+	info->event = 0;
+	info->tty = 0;
+	if (info->blocked_open) {
+		if (info->close_delay) {
+			msleep_interruptible(jiffies_to_msecs(info->close_delay));
+		}
+		wake_up_interruptible(&info->open_wait);
+	}
+	info->flags &= ~(ZILOG_NORMAL_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;
+	int char_time;
+
+	if (serial_paranoia_check(info, tty->name, "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) {
+		msleep_interruptible(jiffies_to_msecs(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->name, "rs_hangup"))
+		return;
+
+	rs_flush_buffer(tty);
+	shutdown(info);
+	info->event = 0;
+	info->count = 0;
+	info->flags &= ~ZILOG_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 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 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 |= ZILOG_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);
+#ifdef SERIAL_DEBUG_OPEN
+	printk("block_til_ready before block: ttyS%d, 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 (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_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%d, 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%d, 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 = tty->index;
+	if ((line < 0) || (line >= zs_channels_found))
+		return -ENODEV;
+	info = zs_soft + line;
+
+	if (info->hook)
+		return -ENODEV;
+
+	if (serial_paranoia_check(info, tty->name, "rs_open"))
+		return -ENODEV;
+#ifdef SERIAL_DEBUG_OPEN
+	printk("rs_open %s, count = %d\n", tty->name, 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;
+	}
+
+#ifdef CONFIG_SERIAL_DEC_CONSOLE
+	if (sercons.cflag && sercons.index == line) {
+		tty->termios->c_cflag = sercons.cflag;
+		sercons.cflag = 0;
+		change_speed(info);
+	}
+#endif
+
+#ifdef SERIAL_DEBUG_OPEN
+	printk("rs_open %s successful...", tty->name);
+#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 0.09\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_MACH_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
+	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 (!request_region((unsigned long)
+					 zs_channels[n_channels].control,
+					 ZS_CHAN_IO_SIZE, "SCC"))
+				panic("SCC I/O region is not free");
+#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);
+}
+
+static struct tty_operations serial_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,
+	.break_ctl = rs_break,
+	.wait_until_sent = rs_wait_until_sent,
+	.tiocmget = rs_tiocmget,
+	.tiocmset = rs_tiocmset,
+};
+
+/* 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();
+	serial_driver = alloc_tty_driver(zs_channels_found);
+	if (!serial_driver)
+		return -ENOMEM;
+
+	show_serial_version();
+
+	/* Initialize the tty_driver structure */
+	/* Not all of this is exactly right for us. */
+
+	serial_driver->owner = THIS_MODULE;
+	serial_driver->devfs_name = "tts/";
+	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 =
+		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+	serial_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
+	tty_set_operations(serial_driver, &serial_ops);
+
+	if (tty_register_driver(serial_driver))
+		panic("Couldn't register serial 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;
+		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_device(serial_driver, info->line, NULL);
+
+	}
+
+	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(void *handle, unsigned char ch)
+{
+	struct dec_serial *info = handle;
+	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(void *handle)
+{
+	struct dec_serial *info = handle;
+        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;
+}
+
+int register_zs_hook(unsigned int channel, struct dec_serial_hook *hook)
+{
+	struct dec_serial *info = &zs_soft[channel];
+
+	if (info->hook) {
+		printk("%s: line %d has already a hook registered\n",
+		       __FUNCTION__, 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;
+	}
+}
+
+int unregister_zs_hook(unsigned int channel)
+{
+	struct dec_serial *info = &zs_soft[channel];
+
+        if (info->hook) {
+                info->hook = NULL;
+                return 1;
+        } else {
+                printk("%s: trying to unregister hook on line %d,"
+                       " but none is registered\n", __FUNCTION__, 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 struct tty_driver *serial_console_device(struct console *c, int *index)
+{
+	*index = c->index;
+	return serial_driver;
+}
+
+/*
+ *	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(void *handle)
+{
+	return 0;
+}
+
+static void kgdbhook_init_info(void *handle)
+{
+}
+
+static void kgdbhook_rx_char(void *handle, unsigned char ch, unsigned char fl)
+{
+	struct dec_serial *info = handle;
+
+	if (fl != TTY_NORMAL)
+		return;
+	if (ch == 0x03 || ch == '$')
+		breakpoint();
+}
+
+/* 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 dec_serial_hook zs_kgdbhook = {
+	.init_channel	= kgdbhook_init_channel,
+	.init_info	= kgdbhook_init_info,
+	.rx_char	= kgdbhook_rx_char,
+	.cflags		= B38400 | CS8 | CLOCAL,
+}
+
+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 */
+
+