[PATCH] Driver Core: drivers/base - drivers/i2c/chips/adm1026.c: update device attrib...

[linux-2.6] / drivers / macintosh / macserial.c

/*
 * macserial.c: Serial port driver for Power Macintoshes.
 *
 * Derived from drivers/sbus/char/sunserial.c by Paul Mackerras.
 *
 * Copyright (C) 1996 Paul Mackerras (Paul.Mackerras@cs.anu.edu.au)
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 *
 * Receive DMA code by Takashi Oe <toe@unlserve.unl.edu>.
 *
 * $Id: macserial.c,v 1.24.2.4 1999/10/19 04:36:42 paulus Exp $
 */

#include <linux/config.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/workqueue.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>
#ifdef CONFIG_SERIAL_CONSOLE
#include <linux/console.h>
#endif
#include <linux/slab.h>
#include <linux/bitops.h>

#include <asm/sections.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/prom.h>
#include <asm/system.h>
#include <asm/segment.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#include <linux/adb.h>
#include <linux/pmu.h>
#ifdef CONFIG_KGDB
#include <asm/kgdb.h>
#endif
#include <asm/dbdma.h>

#include "macserial.h"

#ifdef CONFIG_PMAC_PBOOK
static int serial_notify_sleep(struct pmu_sleep_notifier *self, int when);
static struct pmu_sleep_notifier serial_sleep_notifier = {
        serial_notify_sleep,
        SLEEP_LEVEL_MISC,
};
#endif

#define SUPPORT_SERIAL_DMA
#define MACSERIAL_VERSION       "2.0"

/*
 * 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 */

/* On PowerMacs, the hardware takes care of the SCC recovery time,
   but we need the eieio to make sure that the accesses occur
   in the order we want. */
#define RECOVERY_DELAY  eieio()

static struct tty_driver *serial_driver;

struct mac_zschannel zs_channels[NUM_CHANNELS];

struct mac_serial zs_soft[NUM_CHANNELS];
int zs_channels_found;
struct mac_serial *zs_chain;    /* list of all channels */

struct tty_struct zs_ttys[NUM_CHANNELS];

static int is_powerbook;

#ifdef CONFIG_SERIAL_CONSOLE
static struct console sercons;
#endif

#ifdef CONFIG_KGDB
struct mac_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)*/
};
#endif
#define ZS_CLOCK         3686400        /* Z8530 RTxC input clock rate */

/* 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_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW
#undef SERIAL_DEBUG_POWER
#undef SERIAL_DEBUG_THROTTLE
#undef SERIAL_DEBUG_STOP
#undef SERIAL_DEBUG_BAUDS

#define RS_STROBE_TIME 10
#define RS_ISR_PASS_LIMIT 256

#define _INLINE_ inline

#ifdef SERIAL_DEBUG_OPEN
#define OPNDBG(fmt, arg...)     printk(KERN_DEBUG fmt , ## arg)
#else
#define OPNDBG(fmt, arg...)     do { } while (0)
#endif
#ifdef SERIAL_DEBUG_POWER
#define PWRDBG(fmt, arg...)     printk(KERN_DEBUG fmt , ## arg)
#else
#define PWRDBG(fmt, arg...)     do { } while (0)
#endif
#ifdef SERIAL_DEBUG_BAUDS
#define BAUDBG(fmt, arg...)     printk(fmt , ## arg)
#else
#define BAUDBG(fmt, arg...)     do { } while (0)
#endif

static void probe_sccs(void);
static void change_speed(struct mac_serial *info, struct termios *old);
static void rs_wait_until_sent(struct tty_struct *tty, int timeout);
static int set_scc_power(struct mac_serial * info, int state);
static int setup_scc(struct mac_serial * info);
static void dbdma_reset(volatile struct dbdma_regs *dma);
static void dbdma_flush(volatile struct dbdma_regs *dma);
static irqreturn_t rs_txdma_irq(int irq, void *dev_id, struct pt_regs *regs);
static irqreturn_t rs_rxdma_irq(int irq, void *dev_id, struct pt_regs *regs);
static void dma_init(struct mac_serial * info);
static void rxdma_start(struct mac_serial * info, int curr);
static void rxdma_to_tty(struct mac_serial * info);

/*
 * 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;
static DECLARE_MUTEX(tmp_buf_sem);


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

/* 
 * Reading and writing Z8530 registers.
 */
static inline unsigned char __pmac read_zsreg(struct mac_zschannel *channel,
                                              unsigned char reg)
{
        unsigned char retval;
        unsigned long flags;

        /*
         * We have to make this atomic.
         */
        spin_lock_irqsave(&channel->lock, flags);
        if (reg != 0) {
                *channel->control = reg;
                RECOVERY_DELAY;
        }
        retval = *channel->control;
        RECOVERY_DELAY;
        spin_unlock_irqrestore(&channel->lock, flags);
        return retval;
}

static inline void __pmac write_zsreg(struct mac_zschannel *channel,
                                      unsigned char reg, unsigned char value)
{
        unsigned long flags;

        spin_lock_irqsave(&channel->lock, flags);
        if (reg != 0) {
                *channel->control = reg;
                RECOVERY_DELAY;
        }
        *channel->control = value;
        RECOVERY_DELAY;
        spin_unlock_irqrestore(&channel->lock, flags);
        return;
}

static inline unsigned char __pmac read_zsdata(struct mac_zschannel *channel)
{
        unsigned char retval;

        retval = *channel->data;
        RECOVERY_DELAY;
        return retval;
}

static inline void write_zsdata(struct mac_zschannel *channel,
                                unsigned char value)
{
        *channel->data = value;
        RECOVERY_DELAY;
        return;
}

static inline void load_zsregs(struct mac_zschannel *channel,
                               unsigned char *regs)
{
        ZS_CLEARERR(channel);
        ZS_CLEARFIFO(channel);
        /* Load 'em up */
        write_zsreg(channel, R4, regs[R4]);
        write_zsreg(channel, R10, regs[R10]);
        write_zsreg(channel, R3, regs[R3] & ~RxENABLE);
        write_zsreg(channel, R5, regs[R5] & ~TxENAB);
        write_zsreg(channel, R1, regs[R1]);
        write_zsreg(channel, R9, regs[R9]);
        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 mac_serial *ss, int set)
{
        if (set)
                ss->curregs[5] |= (RTS | DTR);
        else
                ss->curregs[5] &= ~(RTS | DTR);
        write_zsreg(ss->zs_channel, 5, ss->curregs[5]);
        return;
}

/* Utility routines for the Zilog */
static inline int get_zsbaud(struct mac_serial *ss)
{
        struct mac_zschannel *channel = ss->zs_channel;
        int brg;

        if ((ss->curregs[R11] & TCBR) == 0) {
                /* higher rates don't use the baud rate generator */
                return (ss->curregs[R4] & X32CLK)? ZS_CLOCK/32: ZS_CLOCK/16;
        }
        /* 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_CLOCK/(ss->clk_divisor)));
}

/* On receive, this clears errors and the receiver interrupts */
static inline void rs_recv_clear(struct mac_zschannel *zsc)
{
        write_zsreg(zsc, 0, ERR_RES);
        write_zsreg(zsc, 0, RES_H_IUS); /* XXX this is unnecessary */
}

/*
 * Reset a Descriptor-Based DMA channel.
 */
static void dbdma_reset(volatile struct dbdma_regs *dma)
{
        int i;

        out_le32(&dma->control, (WAKE|FLUSH|PAUSE|RUN) << 16);

        /*
         * Yes this looks peculiar, but apparently it needs to be this
         * way on some machines.  (We need to make sure the DBDMA
         * engine has actually got the write above and responded
         * to it. - paulus)
         */
        for (i = 200; i > 0; --i)
                if (ld_le32(&dma->status) & RUN)
                        udelay(1);
}

/*
 * Tells a DBDMA channel to stop and write any buffered data
 * it might have to memory.
 */
static _INLINE_ void dbdma_flush(volatile struct dbdma_regs *dma)
{
        int i = 0;

        out_le32(&dma->control, (FLUSH << 16) | FLUSH);
        while (((in_le32(&dma->status) & FLUSH) != 0) && (i++ < 100))
                udelay(1);
}

/*
 * ----------------------------------------------------------------------
 *
 * 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 mac_serial *info,
                                  int event)
{
        info->event |= 1 << event;
        schedule_work(&info->tqueue);
}

/* Work out the flag value for a z8530 status value. */
static _INLINE_ int stat_to_flag(int stat)
{
        int flag;

        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;
        return flag;
}

static _INLINE_ void receive_chars(struct mac_serial *info,
                                   struct pt_regs *regs)
{
        struct tty_struct *tty = info->tty;
        unsigned char ch, stat, flag;

        while ((read_zsreg(info->zs_channel, 0) & Rx_CH_AV) != 0) {

                stat = read_zsreg(info->zs_channel, R1);
                ch = read_zsdata(info->zs_channel);

#ifdef CONFIG_KGDB
                if (info->kgdb_channel) {
                        if (ch == 0x03 || ch == '$')
                                breakpoint();
                        if (stat & (Rx_OVR|FRM_ERR|PAR_ERR))
                                write_zsreg(info->zs_channel, 0, ERR_RES);
                        return;
                }
#endif
                if (!tty)
                        continue;
                if (tty->flip.count >= TTY_FLIPBUF_SIZE)
                        tty_flip_buffer_push(tty);

                if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
                        static int flip_buf_ovf;
                        if (++flip_buf_ovf <= 1)
                                printk(KERN_WARNING "FB. overflow: %d\n",
                                                    flip_buf_ovf);
                        break;
                }
                tty->flip.count++;
                {
                        static int flip_max_cnt;
                        if (flip_max_cnt < tty->flip.count)
                                flip_max_cnt = tty->flip.count;
                }
                flag = stat_to_flag(stat);
                if (flag)
                        /* reset the error indication */
                        write_zsreg(info->zs_channel, 0, ERR_RES);
                *tty->flip.flag_buf_ptr++ = flag;
                *tty->flip.char_buf_ptr++ = ch;
        }
        if (tty)
                tty_flip_buffer_push(tty);
}

static void transmit_chars(struct mac_serial *info)
{
        if ((read_zsreg(info->zs_channel, 0) & Tx_BUF_EMP) == 0)
                return;
        info->tx_active = 0;

        if (info->x_char && !info->power_wait) {
                /* 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->stopped || info->tx_stopped
            || info->power_wait) {
                write_zsreg(info->zs_channel, 0, 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 void powerup_done(unsigned long data)
{
        struct mac_serial *info = (struct mac_serial *) data;
        unsigned long flags;

        spin_lock_irqsave(&info->lock, flags);
        info->power_wait = 0;
        transmit_chars(info);
        spin_unlock_irqrestore(&info->lock, flags);
}

static _INLINE_ void status_handle(struct mac_serial *info)
{
        unsigned char status;

        /* Get status from Read Register 0 */
        status = read_zsreg(info->zs_channel, 0);

        /* Check for DCD transitions */
        if (((status ^ info->read_reg_zero) & DCD) != 0
            && info->tty && !C_CLOCAL(info->tty)) {
                if (status & DCD) {
                        wake_up_interruptible(&info->open_wait);
                } else {
                        if (info->tty)
                                tty_hangup(info->tty);
                }
        }

        /* Check for CTS transitions */
        if (info->tty && C_CRTSCTS(info->tty)) {
                /*
                 * For some reason, on the Power Macintosh,
                 * it seems that the CTS bit is 1 when CTS is
                 * *negated* and 0 when it is asserted.
                 * The DCD bit doesn't seem to be inverted
                 * like this.
                 */
                if ((status & CTS) == 0) {
                        if (info->tx_stopped) {
#ifdef SERIAL_DEBUG_FLOW
                                printk(KERN_DEBUG "CTS up\n");
#endif
                                info->tx_stopped = 0;
                                if (!info->tx_active)
                                        transmit_chars(info);
                        }
                } else {
#ifdef SERIAL_DEBUG_FLOW
                        printk(KERN_DEBUG "CTS down\n");
#endif
                        info->tx_stopped = 1;
                }
        }

        /* Clear status condition... */
        write_zsreg(info->zs_channel, 0, RES_EXT_INT);
        info->read_reg_zero = status;
}

static _INLINE_ void receive_special_dma(struct mac_serial *info)
{
        unsigned char stat, flag;
        volatile struct dbdma_regs *rd = &info->rx->dma;
        int where = RX_BUF_SIZE;

        spin_lock(&info->rx_dma_lock);
        if ((ld_le32(&rd->status) & ACTIVE) != 0)
                dbdma_flush(rd);
        if (in_le32(&rd->cmdptr)
            == virt_to_bus(info->rx_cmds[info->rx_cbuf] + 1))
                where -= in_le16(&info->rx->res_count);
        where--;

        stat = read_zsreg(info->zs_channel, R1);

        flag = stat_to_flag(stat);
        if (flag) {
                info->rx_flag_buf[info->rx_cbuf][where] = flag;
                /* reset the error indication */
                write_zsreg(info->zs_channel, 0, ERR_RES);
        }

        spin_unlock(&info->rx_dma_lock);
}

/*
 * This is the serial driver's generic interrupt routine
 */
static irqreturn_t rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        struct mac_serial *info = (struct mac_serial *) dev_id;
        unsigned char zs_intreg;
        int shift;
        unsigned long flags;
        int handled = 0;

        if (!(info->flags & ZILOG_INITIALIZED)) {
                printk(KERN_WARNING "rs_interrupt: irq %d, port not "
                                    "initialized\n", irq);
                disable_irq(irq);
                return IRQ_NONE;
        }

        /* 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 */

        spin_lock_irqsave(&info->lock, flags);
        for (;;) {
                zs_intreg = read_zsreg(info->zs_chan_a, 3) >> shift;
#ifdef SERIAL_DEBUG_INTR
                printk(KERN_DEBUG "rs_interrupt: irq %d, zs_intreg 0x%x\n",
                       irq, (int)zs_intreg);
#endif

                if ((zs_intreg & CHAN_IRQMASK) == 0)
                        break;
                handled = 1;

                if (zs_intreg & CHBRxIP) {
                        /* If we are doing DMA, we only ask for interrupts
                           on characters with errors or special conditions. */
                        if (info->dma_initted)
                                receive_special_dma(info);
                        else
                                receive_chars(info, regs);
                }
                if (zs_intreg & CHBTxIP)
                        transmit_chars(info);
                if (zs_intreg & CHBEXT)
                        status_handle(info);
        }
        spin_unlock_irqrestore(&info->lock, flags);
        return IRQ_RETVAL(handled);
}

/* Transmit DMA interrupt - not used at present */
static irqreturn_t rs_txdma_irq(int irq, void *dev_id, struct pt_regs *regs)
{
        return IRQ_HANDLED;
}

/*
 * Receive DMA interrupt.
 */
static irqreturn_t rs_rxdma_irq(int irq, void *dev_id, struct pt_regs *regs)
{
        struct mac_serial *info = (struct mac_serial *) dev_id;
        volatile struct dbdma_cmd *cd;

        if (!info->dma_initted)
                return IRQ_NONE;
        spin_lock(&info->rx_dma_lock);
        /* First, confirm that this interrupt is, indeed, coming */
        /* from Rx DMA */
        cd = info->rx_cmds[info->rx_cbuf] + 2;
        if ((in_le16(&cd->xfer_status) & (RUN | ACTIVE)) != (RUN | ACTIVE)) {
                spin_unlock(&info->rx_dma_lock);
                return IRQ_NONE;
        }
        if (info->rx_fbuf != RX_NO_FBUF) {
                info->rx_cbuf = info->rx_fbuf;
                if (++info->rx_fbuf == info->rx_nbuf)
                        info->rx_fbuf = 0;
                if (info->rx_fbuf == info->rx_ubuf)
                        info->rx_fbuf = RX_NO_FBUF;
        }
        spin_unlock(&info->rx_dma_lock);
        return IRQ_HANDLED;
}

/*
 * -------------------------------------------------------------------
 * 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 mac_serial *info = (struct mac_serial *)tty->driver_data;

#ifdef SERIAL_DEBUG_STOP
        printk(KERN_DEBUG "rs_stop %ld....\n",
               tty->ldisc.chars_in_buffer(tty));
#endif

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

#if 0
        spin_lock_irqsave(&info->lock, flags);
        if (info->curregs[5] & TxENAB) {
                info->curregs[5] &= ~TxENAB;
                info->pendregs[5] &= ~TxENAB;
                write_zsreg(info->zs_channel, 5, info->curregs[5]);
        }
        spin_unlock_irqrestore(&info->lock, flags);
#endif
}

static void rs_start(struct tty_struct *tty)
{
        struct mac_serial *info = (struct mac_serial *)tty->driver_data;
        unsigned long flags;

#ifdef SERIAL_DEBUG_STOP
        printk(KERN_DEBUG "rs_start %ld....\n", 
               tty->ldisc.chars_in_buffer(tty));
#endif

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

        spin_lock_irqsave(&info->lock, flags);
#if 0
        if (info->xmit_cnt && info->xmit_buf && !(info->curregs[5] & TxENAB)) {
                info->curregs[5] |= TxENAB;
                info->pendregs[5] = info->curregs[5];
                write_zsreg(info->zs_channel, 5, info->curregs[5]);
        }
#else
        if (info->xmit_cnt && info->xmit_buf && !info->tx_active) {
                transmit_chars(info);
        }
#endif
        spin_unlock_irqrestore(&info->lock, flags);
}

static void do_softint(void *private_)
{
        struct mac_serial       *info = (struct mac_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);
}

static int startup(struct mac_serial * info)
{
        int delay;

        OPNDBG("startup() (ttyS%d, irq %d)\n", info->line, info->irq);
 
        if (info->flags & ZILOG_INITIALIZED) {
                OPNDBG(" -> already inited\n");
                return 0;
        }

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

        OPNDBG("starting up ttyS%d (irq %d)...\n", info->line, info->irq);

        delay = set_scc_power(info, 1);

        setup_scc(info);

        if (delay) {
                unsigned long flags;

                /* delay is in ms */
                spin_lock_irqsave(&info->lock, flags);
                info->power_wait = 1;
                mod_timer(&info->powerup_timer,
                          jiffies + (delay * HZ + 999) / 1000);
                spin_unlock_irqrestore(&info->lock, flags);
        }

        OPNDBG("enabling IRQ on ttyS%d (irq %d)...\n", info->line, info->irq);

        info->flags |= ZILOG_INITIALIZED;
        enable_irq(info->irq);
        if (info->dma_initted) {
                enable_irq(info->rx_dma_irq);
        }

        return 0;
}

static _INLINE_ void rxdma_start(struct mac_serial * info, int curr)
{
        volatile struct dbdma_regs *rd = &info->rx->dma;
        volatile struct dbdma_cmd *cd = info->rx_cmds[curr];

//printk(KERN_DEBUG "SCC: rxdma_start\n");

        st_le32(&rd->cmdptr, virt_to_bus(cd));
        out_le32(&rd->control, (RUN << 16) | RUN);
}

static void rxdma_to_tty(struct mac_serial *info)
{
        struct tty_struct       *tty = info->tty;
        volatile struct dbdma_regs *rd = &info->rx->dma;
        unsigned long flags;
        int residue, available, space, do_queue;

        if (!tty)
                return;

        do_queue = 0;
        spin_lock_irqsave(&info->rx_dma_lock, flags);
more:
        space = TTY_FLIPBUF_SIZE - tty->flip.count;
        if (!space) {
                do_queue++;
                goto out;
        }
        residue = 0;
        if (info->rx_ubuf == info->rx_cbuf) {
                if ((ld_le32(&rd->status) & ACTIVE) != 0) {
                        dbdma_flush(rd);
                        if (in_le32(&rd->cmdptr)
                            == virt_to_bus(info->rx_cmds[info->rx_cbuf]+1))
                                residue = in_le16(&info->rx->res_count);
                }
        }
        available = RX_BUF_SIZE - residue - info->rx_done_bytes;
        if (available > space)
                available = space;
        if (available) {
                memcpy(tty->flip.char_buf_ptr,
                       info->rx_char_buf[info->rx_ubuf] + info->rx_done_bytes,
                       available);
                memcpy(tty->flip.flag_buf_ptr,
                       info->rx_flag_buf[info->rx_ubuf] + info->rx_done_bytes,
                       available);
                tty->flip.char_buf_ptr += available;
                tty->flip.count += available;
                tty->flip.flag_buf_ptr += available;
                memset(info->rx_flag_buf[info->rx_ubuf] + info->rx_done_bytes,
                       0, available);
                info->rx_done_bytes += available;
                do_queue++;
        }
        if (info->rx_done_bytes == RX_BUF_SIZE) {
                volatile struct dbdma_cmd *cd = info->rx_cmds[info->rx_ubuf];

                if (info->rx_ubuf == info->rx_cbuf)
                        goto out;
                /* mark rx_char_buf[rx_ubuf] free */
                st_le16(&cd->command, DBDMA_NOP);
                cd++;
                st_le32(&cd->cmd_dep, 0);
                st_le32((unsigned int *)&cd->res_count, 0);
                cd++;
                st_le16(&cd->xfer_status, 0);

                if (info->rx_fbuf == RX_NO_FBUF) {
                        info->rx_fbuf = info->rx_ubuf;
                        if (!(ld_le32(&rd->status) & ACTIVE)) {
                                dbdma_reset(&info->rx->dma);
                                rxdma_start(info, info->rx_ubuf);
                                info->rx_cbuf = info->rx_ubuf;
                        }
                }
                info->rx_done_bytes = 0;
                if (++info->rx_ubuf == info->rx_nbuf)
                        info->rx_ubuf = 0;
                if (info->rx_fbuf == info->rx_ubuf)
                        info->rx_fbuf = RX_NO_FBUF;
                goto more;
        }
out:
        spin_unlock_irqrestore(&info->rx_dma_lock, flags);
        if (do_queue)
                tty_flip_buffer_push(tty);
}

static void poll_rxdma(unsigned long private_)
{
        struct mac_serial       *info = (struct mac_serial *) private_;
        unsigned long flags;

        rxdma_to_tty(info);
        spin_lock_irqsave(&info->rx_dma_lock, flags);
        mod_timer(&info->poll_dma_timer, RX_DMA_TIMER);
        spin_unlock_irqrestore(&info->rx_dma_lock, flags);
}

static void dma_init(struct mac_serial * info)
{
        int i, size;
        volatile struct dbdma_cmd *cd;
        unsigned char *p;

        info->rx_nbuf = 8;

        /* various mem set up */
        size = sizeof(struct dbdma_cmd) * (3 * info->rx_nbuf + 2)
                + (RX_BUF_SIZE * 2 + sizeof(*info->rx_cmds)
                   + sizeof(*info->rx_char_buf) + sizeof(*info->rx_flag_buf))
                * info->rx_nbuf;
        info->dma_priv = kmalloc(size, GFP_KERNEL | GFP_DMA);
        if (info->dma_priv == NULL)
                return;
        memset(info->dma_priv, 0, size);

        info->rx_cmds = (volatile struct dbdma_cmd **)info->dma_priv;
        info->rx_char_buf = (unsigned char **) (info->rx_cmds + info->rx_nbuf);
        info->rx_flag_buf = info->rx_char_buf + info->rx_nbuf;
        p = (unsigned char *) (info->rx_flag_buf + info->rx_nbuf);
        for (i = 0; i < info->rx_nbuf; i++, p += RX_BUF_SIZE)
                info->rx_char_buf[i] = p;
        for (i = 0; i < info->rx_nbuf; i++, p += RX_BUF_SIZE)
                info->rx_flag_buf[i] = p;

        /* a bit of DMA programming */
        cd = info->rx_cmds[0] = (volatile struct dbdma_cmd *) DBDMA_ALIGN(p);
        st_le16(&cd->command, DBDMA_NOP);
        cd++;
        st_le16(&cd->req_count, RX_BUF_SIZE);
        st_le16(&cd->command, INPUT_MORE);
        st_le32(&cd->phy_addr, virt_to_bus(info->rx_char_buf[0]));
        cd++;
        st_le16(&cd->req_count, 4);
        st_le16(&cd->command, STORE_WORD | INTR_ALWAYS);
        st_le32(&cd->phy_addr, virt_to_bus(cd-2));
        st_le32(&cd->cmd_dep, DBDMA_STOP);
        for (i = 1; i < info->rx_nbuf; i++) {
                info->rx_cmds[i] = ++cd;
                st_le16(&cd->command, DBDMA_NOP);
                cd++;
                st_le16(&cd->req_count, RX_BUF_SIZE);
                st_le16(&cd->command, INPUT_MORE);
                st_le32(&cd->phy_addr, virt_to_bus(info->rx_char_buf[i]));
                cd++;
                st_le16(&cd->req_count, 4);
                st_le16(&cd->command, STORE_WORD | INTR_ALWAYS);
                st_le32(&cd->phy_addr, virt_to_bus(cd-2));
                st_le32(&cd->cmd_dep, DBDMA_STOP);
        }
        cd++;
        st_le16(&cd->command, DBDMA_NOP | BR_ALWAYS);
        st_le32(&cd->cmd_dep, virt_to_bus(info->rx_cmds[0]));

        /* setup DMA to our liking */
        dbdma_reset(&info->rx->dma);
        st_le32(&info->rx->dma.intr_sel, 0x10001);
        st_le32(&info->rx->dma.br_sel, 0x10001);
        out_le32(&info->rx->dma.wait_sel, 0x10001);

        /* set various flags */
        info->rx_ubuf = 0;
        info->rx_cbuf = 0;
        info->rx_fbuf = info->rx_ubuf + 1;
        if (info->rx_fbuf == info->rx_nbuf)
                info->rx_fbuf = RX_NO_FBUF;
        info->rx_done_bytes = 0;

        /* setup polling */
        init_timer(&info->poll_dma_timer);
        info->poll_dma_timer.function = (void *)&poll_rxdma;
        info->poll_dma_timer.data = (unsigned long)info;

        info->dma_initted = 1;
}

/*
 * FixZeroBug....Works around a bug in the SCC receving channel.
 * Taken from Darwin code, 15 Sept. 2000  -DanM
 *
 * The following sequence prevents a problem that is seen with O'Hare ASICs
 * (most versions -- also with some Heathrow and Hydra ASICs) where a zero
 * at the input to the receiver becomes 'stuck' and locks up the receiver.
 * This problem can occur as a result of a zero bit at the receiver input
 * coincident with any of the following events:
 *
 *      The SCC is initialized (hardware or software).
 *      A framing error is detected.
 *      The clocking option changes from synchronous or X1 asynchronous
 *              clocking to X16, X32, or X64 asynchronous clocking.
 *      The decoding mode is changed among NRZ, NRZI, FM0, or FM1.
 *
 * This workaround attempts to recover from the lockup condition by placing
 * the SCC in synchronous loopback mode with a fast clock before programming
 * any of the asynchronous modes.
 */
static void fix_zero_bug_scc(struct mac_serial * info)
{
        write_zsreg(info->zs_channel, 9,
                    (info->zs_channel == info->zs_chan_a? CHRA: CHRB));
        udelay(10);
        write_zsreg(info->zs_channel, 9,
                    ((info->zs_channel == info->zs_chan_a? CHRA: CHRB) | NV));

        write_zsreg(info->zs_channel, 4, (X1CLK | EXTSYNC));

        /* I think this is wrong....but, I just copying code....
        */
        write_zsreg(info->zs_channel, 3, (8 & ~RxENABLE));

        write_zsreg(info->zs_channel, 5, (8 & ~TxENAB));
        write_zsreg(info->zs_channel, 9, NV);   /* Didn't we already do this? */
        write_zsreg(info->zs_channel, 11, (RCBR | TCBR));
        write_zsreg(info->zs_channel, 12, 0);
        write_zsreg(info->zs_channel, 13, 0);
        write_zsreg(info->zs_channel, 14, (LOOPBAK | SSBR));
        write_zsreg(info->zs_channel, 14, (LOOPBAK | SSBR | BRENABL));
        write_zsreg(info->zs_channel, 3, (8 | RxENABLE));
        write_zsreg(info->zs_channel, 0, RES_EXT_INT);
        write_zsreg(info->zs_channel, 0, RES_EXT_INT);  /* to kill some time */

        /* The channel should be OK now, but it is probably receiving
         * loopback garbage.
         * Switch to asynchronous mode, disable the receiver,
         * and discard everything in the receive buffer.
         */
        write_zsreg(info->zs_channel, 9, NV);
        write_zsreg(info->zs_channel, 4, PAR_ENA);
        write_zsreg(info->zs_channel, 3, (8 & ~RxENABLE));

        while (read_zsreg(info->zs_channel, 0) & Rx_CH_AV) {
                (void)read_zsreg(info->zs_channel, 8);
                write_zsreg(info->zs_channel, 0, RES_EXT_INT);
                write_zsreg(info->zs_channel, 0, ERR_RES);
        }
}

static int setup_scc(struct mac_serial * info)
{
        unsigned long flags;

        OPNDBG("setting up ttyS%d SCC...\n", info->line);

        spin_lock_irqsave(&info->lock, flags);

        /* Nice buggy HW ... */
        fix_zero_bug_scc(info);

        /*
         * Reset the chip.
         */
        write_zsreg(info->zs_channel, 9,
                    (info->zs_channel == info->zs_chan_a? CHRA: CHRB));
        udelay(10);
        write_zsreg(info->zs_channel, 9, 0);

        /*
         * Clear the receive FIFO.
         */
        ZS_CLEARFIFO(info->zs_channel);
        info->xmit_fifo_size = 1;

        /*
         * Reset DMAs
         */
        if (info->has_dma)
                dma_init(info);

        /*
         * Clear the interrupt registers.
         */
        write_zsreg(info->zs_channel, 0, ERR_RES);
        write_zsreg(info->zs_channel, 0, RES_H_IUS);

        /*
         * Turn on RTS and DTR.
         */
        if (!info->is_irda)
                zs_rtsdtr(info, 1);

        /*
         * Finally, enable sequencing and interrupts
         */
        if (!info->dma_initted) {
                /* interrupt on ext/status changes, all received chars,
                   transmit ready */
                info->curregs[1] = (info->curregs[1] & ~0x18)
                                | (EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB);
        } else {
                /* interrupt on ext/status changes, W/Req pin is
                   receive DMA request */
                info->curregs[1] = (info->curregs[1] & ~(0x18 | TxINT_ENAB))
                                | (EXT_INT_ENAB | WT_RDY_RT | WT_FN_RDYFN);
                write_zsreg(info->zs_channel, 1, info->curregs[1]);
                /* enable W/Req pin */
                info->curregs[1] |= WT_RDY_ENAB;
                write_zsreg(info->zs_channel, 1, info->curregs[1]);
                /* enable interrupts on transmit ready and receive errors */
                info->curregs[1] |= INT_ERR_Rx | TxINT_ENAB;
        }
        info->pendregs[1] = info->curregs[1];
        info->curregs[3] |= (RxENABLE | Rx8);
        info->pendregs[3] = info->curregs[3];
        info->curregs[5] |= (TxENAB | Tx8);
        info->pendregs[5] = info->curregs[5];
        info->curregs[9] |= (NV | MIE);
        info->pendregs[9] = info->curregs[9];
        write_zsreg(info->zs_channel, 3, info->curregs[3]);
        write_zsreg(info->zs_channel, 5, info->curregs[5]);
        write_zsreg(info->zs_channel, 9, info->curregs[9]);

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

        spin_unlock_irqrestore(&info->lock, flags);

        /*
         * Set the speed of the serial port
         */
        change_speed(info, 0);

        /* Save the current value of RR0 */
        info->read_reg_zero = read_zsreg(info->zs_channel, 0);

        if (info->dma_initted) {
                spin_lock_irqsave(&info->rx_dma_lock, flags);
                rxdma_start(info, 0);
                info->poll_dma_timer.expires = RX_DMA_TIMER;
                add_timer(&info->poll_dma_timer);
                spin_unlock_irqrestore(&info->rx_dma_lock, 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 mac_serial * info)
{
        OPNDBG("Shutting down serial port %d (irq %d)....\n", info->line,
               info->irq);

        if (!(info->flags & ZILOG_INITIALIZED)) {
                OPNDBG("(already shutdown)\n");
                return;
        }

        if (info->has_dma) {
                del_timer(&info->poll_dma_timer);
                dbdma_reset(info->tx_dma);
                dbdma_reset(&info->rx->dma);
                disable_irq(info->tx_dma_irq);
                disable_irq(info->rx_dma_irq);
        }
        disable_irq(info->irq);

        info->pendregs[1] = info->curregs[1] = 0;
        write_zsreg(info->zs_channel, 1, 0);    /* no interrupts */

        info->curregs[3] &= ~RxENABLE;
        info->pendregs[3] = info->curregs[3];
        write_zsreg(info->zs_channel, 3, info->curregs[3]);

        info->curregs[5] &= ~TxENAB;
        if (!info->tty || C_HUPCL(info->tty))
                info->curregs[5] &= ~DTR;
        info->pendregs[5] = info->curregs[5];
        write_zsreg(info->zs_channel, 5, info->curregs[5]);

        if (info->tty)
                set_bit(TTY_IO_ERROR, &info->tty->flags);

        set_scc_power(info, 0);

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

        if (info->has_dma && info->dma_priv) {
                kfree(info->dma_priv);
                info->dma_priv = NULL;
                info->dma_initted = 0;
        }

        memset(info->curregs, 0, sizeof(info->curregs));
        memset(info->pendregs, 0, sizeof(info->pendregs));

        info->flags &= ~ZILOG_INITIALIZED;
}

/*
 * Turn power on or off to the SCC and associated stuff
 * (port drivers, modem, IR port, etc.)
 * Returns the number of milliseconds we should wait before
 * trying to use the port.
 */
static int set_scc_power(struct mac_serial * info, int state)
{
        int delay = 0;

        if (state) {
                PWRDBG("ttyS%d: powering up hardware\n", info->line);
                pmac_call_feature(
                        PMAC_FTR_SCC_ENABLE,
                        info->dev_node, info->port_type, 1);
                if (info->is_internal_modem) {
                        pmac_call_feature(
                                PMAC_FTR_MODEM_ENABLE,
                                info->dev_node, 0, 1);
                        delay = 2500;   /* wait for 2.5s before using */
                } else if (info->is_irda)
                        mdelay(50);     /* Do better here once the problems
                                         * with blocking have been ironed out
                                         */
        } else {
                /* TODO: Make that depend on a timer, don't power down
                 * immediately
                 */
                PWRDBG("ttyS%d: shutting down hardware\n", info->line);
                if (info->is_internal_modem) {
                        PWRDBG("ttyS%d: shutting down modem\n", info->line);
                        pmac_call_feature(
                                PMAC_FTR_MODEM_ENABLE,
                                info->dev_node, 0, 0);
                }
                pmac_call_feature(
                        PMAC_FTR_SCC_ENABLE,
                        info->dev_node, info->port_type, 0);
        }
        return delay;
}

static void irda_rts_pulses(struct mac_serial *info, int w)
{
        udelay(w);
        write_zsreg(info->zs_channel, 5, Tx8 | TxENAB);
        udelay(2);
        write_zsreg(info->zs_channel, 5, Tx8 | TxENAB | RTS);
        udelay(8);
        write_zsreg(info->zs_channel, 5, Tx8 | TxENAB);
        udelay(4);
        write_zsreg(info->zs_channel, 5, Tx8 | TxENAB | RTS);
}

/*
 * Set the irda codec on the imac to the specified baud rate.
 */
static void irda_setup(struct mac_serial *info)
{
        int code, speed, t;

        speed = info->tty->termios->c_cflag & CBAUD;
        if (speed < B2400 || speed > B115200)
                return;
        code = 0x4d + B115200 - speed;

        /* disable serial interrupts and receive DMA */
        write_zsreg(info->zs_channel, 1, info->curregs[1] & ~0x9f);

        /* wait for transmitter to drain */
        t = 10000;
        while ((read_zsreg(info->zs_channel, 0) & Tx_BUF_EMP) == 0
               || (read_zsreg(info->zs_channel, 1) & ALL_SNT) == 0) {
                if (--t <= 0) {
                        printk(KERN_ERR "transmitter didn't drain\n");
                        return;
                }
                udelay(10);
        }
        udelay(100);

        /* set to 8 bits, no parity, 19200 baud, RTS on, DTR off */
        write_zsreg(info->zs_channel, 4, X16CLK | SB1);
        write_zsreg(info->zs_channel, 11, TCBR | RCBR);
        t = BPS_TO_BRG(19200, ZS_CLOCK/16);
        write_zsreg(info->zs_channel, 12, t);
        write_zsreg(info->zs_channel, 13, t >> 8);
        write_zsreg(info->zs_channel, 14, BRENABL);
        write_zsreg(info->zs_channel, 3, Rx8 | RxENABLE);
        write_zsreg(info->zs_channel, 5, Tx8 | TxENAB | RTS);

        /* set TxD low for ~104us and pulse RTS */
        udelay(1000);
        write_zsdata(info->zs_channel, 0xfe);
        irda_rts_pulses(info, 150);
        irda_rts_pulses(info, 180);
        irda_rts_pulses(info, 50);
        udelay(100);

        /* assert DTR, wait 30ms, talk to the chip */
        write_zsreg(info->zs_channel, 5, Tx8 | TxENAB | RTS | DTR);
        mdelay(30);
        while (read_zsreg(info->zs_channel, 0) & Rx_CH_AV)
                read_zsdata(info->zs_channel);

        write_zsdata(info->zs_channel, 1);
        t = 1000;
        while ((read_zsreg(info->zs_channel, 0) & Rx_CH_AV) == 0) {
                if (--t <= 0) {
                        printk(KERN_ERR "irda_setup timed out on 1st byte\n");
                        goto out;
                }
                udelay(10);
        }
        t = read_zsdata(info->zs_channel);
        if (t != 4)
                printk(KERN_ERR "irda_setup 1st byte = %x\n", t);

        write_zsdata(info->zs_channel, code);
        t = 1000;
        while ((read_zsreg(info->zs_channel, 0) & Rx_CH_AV) == 0) {
                if (--t <= 0) {
                        printk(KERN_ERR "irda_setup timed out on 2nd byte\n");
                        goto out;
                }
                udelay(10);
        }
        t = read_zsdata(info->zs_channel);
        if (t != code)
                printk(KERN_ERR "irda_setup 2nd byte = %x (%x)\n", t, code);

        /* Drop DTR again and do some more RTS pulses */
 out:
        udelay(100);
        write_zsreg(info->zs_channel, 5, Tx8 | TxENAB | RTS);
        irda_rts_pulses(info, 80);

        /* We should be right to go now.  We assume that load_zsregs
           will get called soon to load up the correct baud rate etc. */
        info->curregs[5] = (info->curregs[5] | RTS) & ~DTR;
        info->pendregs[5] = info->curregs[5];
}

/*
 * 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 mac_serial *info, struct termios *old_termios)
{
        unsigned cflag;
        int     bits;
        int     brg, baud;
        unsigned long flags;

        if (!info->tty || !info->tty->termios)
                return;

        cflag = info->tty->termios->c_cflag;
        baud = tty_get_baud_rate(info->tty);
        if (baud == 0) {
                if (old_termios) {
                        info->tty->termios->c_cflag &= ~CBAUD;
                        info->tty->termios->c_cflag |= (old_termios->c_cflag & CBAUD);
                        cflag = info->tty->termios->c_cflag;
                        baud = tty_get_baud_rate(info->tty);
                }
                else
                        baud = info->zs_baud;
        }
        if (baud > 230400)
                baud = 230400;
        else if (baud == 0)
                baud = 38400;

        spin_lock_irqsave(&info->lock, flags);
        info->zs_baud = baud;
        info->clk_divisor = 16;

        BAUDBG(KERN_DEBUG "set speed to %d bds, ", baud);

        switch (baud) {
        case ZS_CLOCK/16:       /* 230400 */
                info->curregs[4] = X16CLK;
                info->curregs[11] = 0;
                break;
        case ZS_CLOCK/32:       /* 115200 */
                info->curregs[4] = X32CLK;
                info->curregs[11] = 0;
                break;
        default:
                info->curregs[4] = X16CLK;
                info->curregs[11] = TCBR | RCBR;
                brg = BPS_TO_BRG(baud, ZS_CLOCK/info->clk_divisor);
                info->curregs[12] = (brg & 255);
                info->curregs[13] = ((brg >> 8) & 255);
                info->curregs[14] = BRENABL;
        }

        /* byte size and parity */
        info->curregs[3] &= ~RxNBITS_MASK;
        info->curregs[5] &= ~TxNBITS_MASK;
        switch (cflag & CSIZE) {
        case CS5:
                info->curregs[3] |= Rx5;
                info->curregs[5] |= Tx5;
                BAUDBG("5 bits, ");
                bits = 7;
                break;
        case CS6:
                info->curregs[3] |= Rx6;
                info->curregs[5] |= Tx6;
                BAUDBG("6 bits, ");
                bits = 8;
                break;
        case CS7:
                info->curregs[3] |= Rx7;
                info->curregs[5] |= Tx7;
                BAUDBG("7 bits, ");
                bits = 9;
                break;
        case CS8:
        default: /* defaults to 8 bits */
                info->curregs[3] |= Rx8;
                info->curregs[5] |= Tx8;
                BAUDBG("8 bits, ");
                bits = 10;
                break;
        }
        info->pendregs[3] = info->curregs[3];
        info->pendregs[5] = info->curregs[5];

        info->curregs[4] &= ~(SB_MASK | PAR_ENA | PAR_EVEN);
        if (cflag & CSTOPB) {
                info->curregs[4] |= SB2;
                bits++;
                BAUDBG("2 stop, ");
        } else {
                info->curregs[4] |= SB1;
                BAUDBG("1 stop, ");
        }
        if (cflag & PARENB) {
                bits++;
                info->curregs[4] |= PAR_ENA;
                BAUDBG("parity, ");
        }
        if (!(cflag & PARODD)) {
                info->curregs[4] |= PAR_EVEN;
        }
        info->pendregs[4] = info->curregs[4];

        if (!(cflag & CLOCAL)) {
                if (!(info->curregs[15] & DCDIE))
                        info->read_reg_zero = read_zsreg(info->zs_channel, 0);
                info->curregs[15] |= DCDIE;
        } else
                info->curregs[15] &= ~DCDIE;
        if (cflag & CRTSCTS) {
                info->curregs[15] |= CTSIE;
                if ((read_zsreg(info->zs_channel, 0) & CTS) != 0)
                        info->tx_stopped = 1;
        } else {
                info->curregs[15] &= ~CTSIE;
                info->tx_stopped = 0;
        }
        info->pendregs[15] = info->curregs[15];

        /* Calc timeout value. This is pretty broken with high baud rates with HZ=100.
           This code would love a larger HZ and a >1 fifo size, but this is not
           a priority. The resulting value must be >HZ/2
         */
        info->timeout = ((info->xmit_fifo_size*HZ*bits) / baud);
        info->timeout += HZ/50+1;       /* Add .02 seconds of slop */

        BAUDBG("timeout=%d/%ds, base:%d\n", (int)info->timeout, (int)HZ,
               (int)info->baud_base);

        /* set the irda codec to the right rate */
        if (info->is_irda)
                irda_setup(info);

        /* Load up the new values */
        load_zsregs(info->zs_channel, info->curregs);

        spin_unlock_irqrestore(&info->lock, flags);
}

static void rs_flush_chars(struct tty_struct *tty)
{
        struct mac_serial *info = (struct mac_serial *)tty->driver_data;
        unsigned long flags;

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

        spin_lock_irqsave(&info->lock, flags);
        if (!(info->xmit_cnt <= 0 || tty->stopped || info->tx_stopped ||
              !info->xmit_buf))
                /* Enable transmitter */
                transmit_chars(info);
        spin_unlock_irqrestore(&info->lock, flags);
}

static int rs_write(struct tty_struct * tty,
                    const unsigned char *buf, int count)
{
        int     c, ret = 0;
        struct mac_serial *info = (struct mac_serial *)tty->driver_data;
        unsigned long flags;

        if (serial_paranoia_check(info, tty->name, "rs_write"))
                return 0;

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

        while (1) {
                spin_lock_irqsave(&info->lock, flags);
                c = min_t(int, count, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
                                          SERIAL_XMIT_SIZE - info->xmit_head));
                if (c <= 0) {
                        spin_unlock_irqrestore(&info->lock, flags);
                        break;
                }
                memcpy(info->xmit_buf + info->xmit_head, buf, c);
                info->xmit_head = ((info->xmit_head + c) &
                                   (SERIAL_XMIT_SIZE-1));
                info->xmit_cnt += c;
                spin_unlock_irqrestore(&info->lock, flags);
                buf += c;
                count -= c;
                ret += c;
        }
        spin_lock_irqsave(&info->lock, flags);
        if (info->xmit_cnt && !tty->stopped && !info->tx_stopped
            && !info->tx_active)
                transmit_chars(info);
        spin_unlock_irqrestore(&info->lock, flags);
        return ret;
}

static int rs_write_room(struct tty_struct *tty)
{
        struct mac_serial *info = (struct mac_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 mac_serial *info = (struct mac_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 mac_serial *info = (struct mac_serial *)tty->driver_data;
        unsigned long flags;

        if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
                return;
        spin_lock_irqsave(&info->lock, flags);
        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
        spin_unlock_irqrestore(&info->lock, flags);
        tty_wakeup(tty);
}

/*
 * ------------------------------------------------------------
 * rs_throttle()
 * 
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void rs_throttle(struct tty_struct * tty)
{
        struct mac_serial *info = (struct mac_serial *)tty->driver_data;
        unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
        printk(KERN_DEBUG "throttle %ld....\n",tty->ldisc.chars_in_buffer(tty));
#endif

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

        if (I_IXOFF(tty)) {
                spin_lock_irqsave(&info->lock, flags);
                info->x_char = STOP_CHAR(tty);
                if (!info->tx_active)
                        transmit_chars(info);
                spin_unlock_irqrestore(&info->lock, flags);
        }

        if (C_CRTSCTS(tty)) {
                /*
                 * Here we want to turn off the RTS line.  On Macintoshes,
                 * the external serial ports using a DIN-8 or DIN-9
                 * connector only have the DTR line (which is usually
                 * wired to both RTS and DTR on an external modem in
                 * the cable).  RTS doesn't go out to the serial port
                 * socket, it acts as an output enable for the transmit
                 * data line.  So in this case we don't drop RTS.
                 *
                 * Macs with internal modems generally do have both RTS
                 * and DTR wired to the modem, so in that case we do
                 * drop RTS.
                 */
                if (info->is_internal_modem) {
                        spin_lock_irqsave(&info->lock, flags);
                        info->curregs[5] &= ~RTS;
                        info->pendregs[5] &= ~RTS;
                        write_zsreg(info->zs_channel, 5, info->curregs[5]);
                        spin_unlock_irqrestore(&info->lock, flags);
                }
        }
        
#ifdef CDTRCTS
        if (tty->termios->c_cflag & CDTRCTS) {
                spin_lock_irqsave(&info->lock, flags);
                info->curregs[5] &= ~DTR;
                info->pendregs[5] &= ~DTR;
                write_zsreg(info->zs_channel, 5, info->curregs[5]);
                spin_unlock_irqrestore(&info->lock, flags);
        }
#endif /* CDTRCTS */
}

static void rs_unthrottle(struct tty_struct * tty)
{
        struct mac_serial *info = (struct mac_serial *)tty->driver_data;
        unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
        printk(KERN_DEBUG "unthrottle %s: %d....\n",
                        tty->ldisc.chars_in_buffer(tty));
#endif

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

        if (I_IXOFF(tty)) {
                spin_lock_irqsave(&info->lock, flags);
                if (info->x_char)
                        info->x_char = 0;
                else {
                        info->x_char = START_CHAR(tty);
                        if (!info->tx_active)
                                transmit_chars(info);
                }
                spin_unlock_irqrestore(&info->lock, flags);
        }

        if (C_CRTSCTS(tty) && info->is_internal_modem) {
                /* Assert RTS line */
                spin_lock_irqsave(&info->lock, flags);
                info->curregs[5] |= RTS;
                info->pendregs[5] |= RTS;
                write_zsreg(info->zs_channel, 5, info->curregs[5]);
                spin_unlock_irqrestore(&info->lock, flags);
        }

#ifdef CDTRCTS
        if (tty->termios->c_cflag & CDTRCTS) {
                /* Assert DTR line */
                spin_lock_irqsave(&info->lock, flags);
                info->curregs[5] |= DTR;
                info->pendregs[5] |= DTR;
                write_zsreg(info->zs_channel, 5, info->curregs[5]);
                spin_unlock_irqrestore(&info->lock, flags);
        }
#endif
}

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

static int get_serial_info(struct mac_serial * info,
                           struct serial_struct __user * 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;
        if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
                return -EFAULT;
        return 0;
}

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

        if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
                return -EFAULT;
        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:
        if (info->flags & ZILOG_INITIALIZED)
                retval = setup_scc(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 mac_serial * info, unsigned int *value)
{
        unsigned char status;
        unsigned long flags;

        spin_lock_irqsave(&info->lock, flags);
        status = read_zsreg(info->zs_channel, 0);
        spin_unlock_irqrestore(&info->lock, flags);
        status = (status & Tx_BUF_EMP)? TIOCSER_TEMT: 0;
        return put_user(status,value);
}

static int rs_tiocmget(struct tty_struct *tty, struct file *file)
{
        struct mac_serial * info = (struct mac_serial *)tty->driver_data;
        unsigned char control, status;
        unsigned long flags;

#ifdef CONFIG_KGDB
        if (info->kgdb_channel)
                return -ENODEV;
#endif
        if (serial_paranoia_check(info, tty->name, __FUNCTION__))
                return -ENODEV;

        if (tty->flags & (1 << TTY_IO_ERROR))
                return -EIO;

        spin_lock_irqsave(&info->lock, flags);
        control = info->curregs[5];
        status = read_zsreg(info->zs_channel, 0);
        spin_unlock_irqrestore(&info->lock, flags);
        return    ((control & RTS) ? TIOCM_RTS: 0)
                | ((control & DTR) ? TIOCM_DTR: 0)
                | ((status  & DCD) ? TIOCM_CAR: 0)
                | ((status  & CTS) ? 0: TIOCM_CTS);
}

static int rs_tiocmset(struct tty_struct *tty, struct file *file,
                       unsigned int set, unsigned int clear)
{
        struct mac_serial * info = (struct mac_serial *)tty->driver_data;
        unsigned int arg, bits;
        unsigned long flags;

#ifdef CONFIG_KGDB
        if (info->kgdb_channel)
                return -ENODEV;
#endif
        if (serial_paranoia_check(info, tty->name, __FUNCTION__))
                return -ENODEV;

        if (tty->flags & (1 << TTY_IO_ERROR))
                return -EIO;

        spin_lock_irqsave(&info->lock, flags);
        if (set & TIOCM_RTS)
                info->curregs[5] |= RTS;
        if (set & TIOCM_DTR)
                info->curregs[5] |= DTR;
        if (clear & TIOCM_RTS)
                info->curregs[5] &= ~RTS;
        if (clear & TIOCM_DTR)
                info->curregs[5] &= ~DTR;

        info->pendregs[5] = info->curregs[5];
        write_zsreg(info->zs_channel, 5, info->curregs[5]);
        spin_unlock_irqrestore(&info->lock, flags);
        return 0;
}

/*
 * rs_break - turn transmit break condition on/off
 */
static void rs_break(struct tty_struct *tty, int break_state)
{
        struct mac_serial *info = (struct mac_serial *) tty->driver_data;
        unsigned long flags;

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

        spin_lock_irqsave(&info->lock, flags);
        if (break_state == -1)
                info->curregs[5] |= SND_BRK;
        else
                info->curregs[5] &= ~SND_BRK;
        write_zsreg(info->zs_channel, 5, info->curregs[5]);
        spin_unlock_irqrestore(&info->lock, flags);
}

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

#ifdef CONFIG_KGDB
        if (info->kgdb_channel)
                return -ENODEV;
#endif
        if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
                return -ENODEV;

        if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
            (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT)) {
                if (tty->flags & (1 << TTY_IO_ERROR))
                    return -EIO;
        }

        switch (cmd) {
                case TIOCGSERIAL:
                        return get_serial_info(info,
                                        (struct serial_struct __user *) arg);
                case TIOCSSERIAL:
                        return set_serial_info(info,
                                        (struct serial_struct __user *) arg);
                case TIOCSERGETLSR: /* Get line status register */
                        return get_lsr_info(info, (unsigned int *) arg);

                case TIOCSERGSTRUCT:
                        if (copy_to_user((struct mac_serial __user *) arg,
                                         info, sizeof(struct mac_serial)))
                                return -EFAULT;
                        return 0;

                default:
                        return -ENOIOCTLCMD;
                }
        return 0;
}

static void rs_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
        struct mac_serial *info = (struct mac_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, old_termios);

        if (was_stopped && !info->tx_stopped) {
                tty->hw_stopped = 0;
                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 mac_serial * info = (struct mac_serial *)tty->driver_data;
        unsigned long flags;

        if (!info || serial_paranoia_check(info, tty->name, "rs_close"))
                return;

        spin_lock_irqsave(&info->lock, flags);

        if (tty_hung_up_p(filp)) {
                spin_unlock_irqrestore(&info->lock, flags);
                return;
        }

        OPNDBG("rs_close ttyS%d, count = %d\n", info->line, info->count);
        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(KERN_ERR "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(KERN_ERR "rs_close: bad serial port count for "
                                "ttyS%d: %d\n", info->line, info->count);
                info->count = 0;
        }
        if (info->count) {
                spin_unlock_irqrestore(&info->lock, 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.
         */
        OPNDBG("waiting end of Tx... (timeout:%d)\n", info->closing_wait);
        tty->closing = 1;
        if (info->closing_wait != ZILOG_CLOSING_WAIT_NONE) {
                spin_unlock_irqrestore(&info->lock, flags);
                tty_wait_until_sent(tty, info->closing_wait);
                spin_lock_irqsave(&info->lock, flags);
        }

        /*
         * At this point we stop accepting input.  To do this, we
         * disable the receiver and receive interrupts.
         */
        info->curregs[3] &= ~RxENABLE;
        info->pendregs[3] = info->curregs[3];
        write_zsreg(info->zs_channel, 3, info->curregs[3]);
        info->curregs[1] &= ~(0x18);    /* disable any rx ints */
        info->pendregs[1] = info->curregs[1];
        write_zsreg(info->zs_channel, 1, info->curregs[1]);
        ZS_CLEARFIFO(info->zs_channel);
        if (info->flags & ZILOG_INITIALIZED) {
                /*
                 * Before we drop DTR, make sure the SCC transmitter
                 * has completely drained.
                 */
                OPNDBG("waiting end of Rx...\n");
                spin_unlock_irqrestore(&info->lock, flags);
                rs_wait_until_sent(tty, info->timeout);
                spin_lock_irqsave(&info->lock, flags);
        }

        shutdown(info);
        /* restore flags now since shutdown() will have disabled this port's
           specific irqs */
        spin_unlock_irqrestore(&info->lock, flags);

        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);
}

/*
 * rs_wait_until_sent() --- wait until the transmitter is empty
 */
static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
{
        struct mac_serial *info = (struct mac_serial *) tty->driver_data;
        unsigned long orig_jiffies, char_time;

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

/*      printk("rs_wait_until_sent, timeout:%d, tty_stopped:%d, tx_stopped:%d\n",
                        timeout, tty->stopped, info->tx_stopped);
*/
        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.
         */
        if (info->timeout <= HZ/50) {
                printk(KERN_INFO "macserial: invalid info->timeout=%d\n",
                                    info->timeout);
                info->timeout = HZ/50+1;
        }

        char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
        char_time = char_time / 5;
        if (char_time > HZ) {
                printk(KERN_WARNING "macserial: char_time %ld >HZ !!!\n",
                                    char_time);
                char_time = 1;
        } else if (char_time == 0)
                char_time = 1;
        if (timeout)
                char_time = min_t(unsigned long, char_time, timeout);
        while ((read_zsreg(info->zs_channel, 1) & ALL_SNT) == 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.
 */
static void rs_hangup(struct tty_struct *tty)
{
        struct mac_serial * info = (struct mac_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 mac_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);
                return -EAGAIN;
        }

        /*
         * 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);
        OPNDBG("block_til_ready before block: ttyS%d, count = %d\n",
               info->line, info->count);
        spin_lock_irq(&info->lock);
        if (!tty_hung_up_p(filp)) 
                info->count--;
        spin_unlock_irq(&info->lock);
        info->blocked_open++;
        while (1) {
                spin_lock_irq(&info->lock);
                if ((tty->termios->c_cflag & CBAUD) &&
                    !info->is_irda)
                        zs_rtsdtr(info, 1);
                spin_unlock_irq(&info->lock);
                set_current_state(TASK_INTERRUPTIBLE);
                if (tty_hung_up_p(filp) ||
                    !(info->flags & ZILOG_INITIALIZED)) {
                        retval = -EAGAIN;
                        break;
                }
                if (!(info->flags & ZILOG_CLOSING) &&
                    (do_clocal || (read_zsreg(info->zs_channel, 0) & DCD)))
                        break;
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;
                        break;
                }
                OPNDBG("block_til_ready blocking: ttyS%d, count = %d\n",
                       info->line, info->count);
                schedule();
        }
        current->state = TASK_RUNNING;
        remove_wait_queue(&info->open_wait, &wait);
        if (!tty_hung_up_p(filp))
                info->count++;
        info->blocked_open--;
        OPNDBG("block_til_ready after blocking: ttyS%d, count = %d\n",
               info->line, info->count);
        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.
 */
static int rs_open(struct tty_struct *tty, struct file * filp)
{
        struct mac_serial       *info;
        int                     retval, line;
        unsigned long           page;

        line = tty->index;
        if ((line < 0) || (line >= zs_channels_found)) {
                return -ENODEV;
        }
        info = zs_soft + line;

#ifdef CONFIG_KGDB
        if (info->kgdb_channel) {
                return -ENODEV;
        }
#endif
        if (serial_paranoia_check(info, tty->name, "rs_open"))
                return -ENODEV;
        OPNDBG("rs_open %s, count = %d, tty=%p\n", tty->name,
               info->count, tty);

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

        if (!tmp_buf) {
                page = get_zeroed_page(GFP_KERNEL);
                if (!page)
                        return -ENOMEM;
                if (tmp_buf)
                        free_page(page);
                else
                        tmp_buf = (unsigned char *) page;
        }

        /*
         * 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);
                return -EAGAIN;
        }

        /*
         * Start up serial port
         */

        retval = startup(info);
        if (retval)
                return retval;

        retval = block_til_ready(tty, filp, info);
        if (retval) {
                OPNDBG("rs_open returning after block_til_ready with %d\n",
                        retval);
                return retval;
        }

#ifdef CONFIG_SERIAL_CONSOLE
        if (sercons.cflag && sercons.index == line) {
                tty->termios->c_cflag = sercons.cflag;
                sercons.cflag = 0;
                change_speed(info, 0);
        }
#endif

        OPNDBG("rs_open %s successful...\n", tty->name);
        return 0;
}

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

static void show_serial_version(void)
{
        printk(KERN_INFO "PowerMac Z8530 serial driver version " MACSERIAL_VERSION "\n");
}

/*
 * Initialize one channel, both the mac_serial and mac_zschannel
 * structs.  We use the dev_node field of the mac_serial struct.
 */
static int
chan_init(struct mac_serial *zss, struct mac_zschannel *zs_chan,
          struct mac_zschannel *zs_chan_a)
{
        struct device_node *ch = zss->dev_node;
        char *conn;
        int len;
        struct slot_names_prop {
                int     count;
                char    name[1];
        } *slots;

        zss->irq = ch->intrs[0].line;
        zss->has_dma = 0;
#if !defined(CONFIG_KGDB) && defined(SUPPORT_SERIAL_DMA)
        if (ch->n_addrs >= 3 && ch->n_intrs == 3)
                zss->has_dma = 1;
#endif
        zss->dma_initted = 0;

        zs_chan->control = (volatile unsigned char *)
                ioremap(ch->addrs[0].address, 0x1000);
        zs_chan->data = zs_chan->control + 0x10;
        spin_lock_init(&zs_chan->lock);
        zs_chan->parent = zss;
        zss->zs_channel = zs_chan;
        zss->zs_chan_a = zs_chan_a;

        /* setup misc varariables */
        zss->kgdb_channel = 0;

        /* For now, we assume you either have a slot-names property
         * with "Modem" in it, or your channel is compatible with
         * "cobalt". Might need additional fixups
         */
        zss->is_internal_modem = device_is_compatible(ch, "cobalt");
        conn = get_property(ch, "AAPL,connector", &len);
        zss->is_irda = conn && (strcmp(conn, "infrared") == 0);
        zss->port_type = PMAC_SCC_ASYNC;
        /* 1999 Powerbook G3 has slot-names property instead */
        slots = (struct slot_names_prop *)get_property(ch, "slot-names", &len);
        if (slots && slots->count > 0) {
                if (strcmp(slots->name, "IrDA") == 0)
                        zss->is_irda = 1;
                else if (strcmp(slots->name, "Modem") == 0)
                        zss->is_internal_modem = 1;
        }
        if (zss->is_irda)
                zss->port_type = PMAC_SCC_IRDA;
        if (zss->is_internal_modem) {
                struct device_node* i2c_modem = find_devices("i2c-modem");
                if (i2c_modem) {
                        char* mid = get_property(i2c_modem, "modem-id", NULL);
                        if (mid) switch(*mid) {
                        case 0x04 :
                        case 0x05 :
                        case 0x07 :
                        case 0x08 :
                        case 0x0b :
                        case 0x0c :
                                zss->port_type = PMAC_SCC_I2S1;
                        }
                        printk(KERN_INFO "macserial: i2c-modem detected, id: %d\n",
                                mid ? (*mid) : 0);
                } else {
                        printk(KERN_INFO "macserial: serial modem detected\n");
                }
        }

        while (zss->has_dma) {
                zss->dma_priv = NULL;
                /* it seems that the last two addresses are the
                   DMA controllers */
                zss->tx_dma = (volatile struct dbdma_regs *)
                        ioremap(ch->addrs[ch->n_addrs - 2].address, 0x100);
                zss->rx = (volatile struct mac_dma *)
                        ioremap(ch->addrs[ch->n_addrs - 1].address, 0x100);
                zss->tx_dma_irq = ch->intrs[1].line;
                zss->rx_dma_irq = ch->intrs[2].line;
                spin_lock_init(&zss->rx_dma_lock);
                break;
        }

        init_timer(&zss->powerup_timer);
        zss->powerup_timer.function = powerup_done;
        zss->powerup_timer.data = (unsigned long) zss;
        return 0;
}

/*
 * /proc fs routines. TODO: Add status lines & error stats
 */
static inline int
line_info(char *buf, struct mac_serial *info)
{
        int             ret=0;
        unsigned char* connector;
        int lenp;

        ret += sprintf(buf, "%d: port:0x%X irq:%d", info->line, info->port, info->irq);

        connector = get_property(info->dev_node, "AAPL,connector", &lenp);
        if (connector)
                ret+=sprintf(buf+ret," con:%s ", connector);
        if (info->is_internal_modem) {
                if (!connector)
                        ret+=sprintf(buf+ret," con:");
                ret+=sprintf(buf+ret,"%s", " (internal modem)");
        }
        if (info->is_irda) {
                if (!connector)
                        ret+=sprintf(buf+ret," con:");
                ret+=sprintf(buf+ret,"%s", " (IrDA)");
        }
        ret+=sprintf(buf+ret,"\n");

        return ret;
}

int macserial_read_proc(char *page, char **start, off_t off, int count,
                 int *eof, void *data)
{
        int l, len = 0;
        off_t   begin = 0;
        struct mac_serial *info;

        len += sprintf(page, "serinfo:1.0 driver:" MACSERIAL_VERSION "\n");
        for (info = zs_chain; info && len < 4000; info = info->zs_next) {
                l = line_info(page + len, info);
                len += l;
                if (len+begin > off+count)
                        goto done;
                if (len+begin < off) {
                        begin += len;
                        len = 0;
                }
        }
        *eof = 1;
done:
        if (off >= len+begin)
                return 0;
        *start = page + (off-begin);
        return ((count < begin+len-off) ? count : begin+len-off);
}

/* Ask the PROM how many Z8530s we have and initialize their zs_channels */
static void
probe_sccs(void)
{
        struct device_node *dev, *ch;
        struct mac_serial **pp;
        int n, chip, nchan;
        struct mac_zschannel *zs_chan;
        int chan_a_index;

        n = 0;
        pp = &zs_chain;
        zs_chan = zs_channels;
        for (dev = find_devices("escc"); dev != 0; dev = dev->next) {
                nchan = 0;
                chip = n;
                if (n >= NUM_CHANNELS) {
                        printk(KERN_WARNING "Sorry, can't use %s: no more "
                                            "channels\n", dev->full_name);
                        continue;
                }
                chan_a_index = 0;
                for (ch = dev->child; ch != 0; ch = ch->sibling) {
                        if (nchan >= 2) {
                                printk(KERN_WARNING "SCC: Only 2 channels per "
                                        "chip are supported\n");
                                break;
                        }
                        if (ch->n_addrs < 1 || (ch ->n_intrs < 1)) {
                                printk("Can't use %s: %d addrs %d intrs\n",
                                      ch->full_name, ch->n_addrs, ch->n_intrs);
                                continue;
                        }

                        /* The channel with the higher address
                           will be the A side. */
                        if (nchan > 0 &&
                            ch->addrs[0].address
                            > zs_soft[n-1].dev_node->addrs[0].address)
                                chan_a_index = 1;

                        /* minimal initialization for now */
                        zs_soft[n].dev_node = ch;
                        *pp = &zs_soft[n];
                        pp = &zs_soft[n].zs_next;
                        ++nchan;
                        ++n;
                }
                if (nchan == 0)
                        continue;

                /* set up A side */
                if (chan_init(&zs_soft[chip + chan_a_index], zs_chan, zs_chan))
                        continue;
                ++zs_chan;

                /* set up B side, if it exists */
                if (nchan > 1)
                        if (chan_init(&zs_soft[chip + 1 - chan_a_index],
                                  zs_chan, zs_chan - 1))
                                continue;
                ++zs_chan;
        }
        *pp = 0;

        zs_channels_found = n;
#ifdef CONFIG_PMAC_PBOOK
        if (n)
                pmu_register_sleep_notifier(&serial_sleep_notifier);
#endif /* CONFIG_PMAC_PBOOK */
}

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,
        .read_proc = macserial_read_proc,
        .tiocmget = rs_tiocmget,
        .tiocmset = rs_tiocmset,
};

static int macserial_init(void)
{
        int channel, i;
        struct mac_serial *info;

        /* 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;

        /* XXX assume it's a powerbook if we have a via-pmu
         * 
         * This is OK for core99 machines as well.
         */
        is_powerbook = find_devices("via-pmu") != 0;

        /* Register the interrupt handler for each one
         * We also request the OF resources here as probe_sccs()
         * might be called too early for that
         */
        for (i = 0; i < zs_channels_found; ++i) {
                struct device_node* ch = zs_soft[i].dev_node;
                if (!request_OF_resource(ch, 0, NULL)) {
                        printk(KERN_ERR "macserial: can't request IO resource !\n");
                        put_tty_driver(serial_driver);
                        return -ENODEV;
                }
                if (zs_soft[i].has_dma) {
                        if (!request_OF_resource(ch, ch->n_addrs - 2, " (tx dma)")) {
                                printk(KERN_ERR "macserial: can't request TX DMA resource !\n");
                                zs_soft[i].has_dma = 0;
                                goto no_dma;
                        }
                        if (!request_OF_resource(ch, ch->n_addrs - 1, " (rx dma)")) {
                                release_OF_resource(ch, ch->n_addrs - 2);
                                printk(KERN_ERR "macserial: can't request RX DMA resource !\n");
                                zs_soft[i].has_dma = 0;
                                goto no_dma;
                        }
                        if (request_irq(zs_soft[i].tx_dma_irq, rs_txdma_irq, 0,
                                        "SCC-txdma", &zs_soft[i]))
                                printk(KERN_ERR "macserial: can't get irq %d\n",
                                       zs_soft[i].tx_dma_irq);
                        disable_irq(zs_soft[i].tx_dma_irq);
                        if (request_irq(zs_soft[i].rx_dma_irq, rs_rxdma_irq, 0,
                                        "SCC-rxdma", &zs_soft[i]))
                                printk(KERN_ERR "macserial: can't get irq %d\n",
                                       zs_soft[i].rx_dma_irq);
                        disable_irq(zs_soft[i].rx_dma_irq);
                }
no_dma:         
                if (request_irq(zs_soft[i].irq, rs_interrupt, 0,
                                "SCC", &zs_soft[i]))
                        printk(KERN_ERR "macserial: can't get irq %d\n",
                               zs_soft[i].irq);
                disable_irq(zs_soft[i].irq);
        }

        show_serial_version();

        /* Initialize the tty_driver structure */
        /* Not all of this is exactly right for us. */

        serial_driver->owner = THIS_MODULE;
        serial_driver->driver_name = "macserial";
        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 =
                B38400 | CS8 | CREAD | HUPCL | CLOCAL;
        serial_driver->flags = TTY_DRIVER_REAL_RAW;
        tty_set_operations(serial_driver, &serial_ops);

        if (tty_register_driver(serial_driver))
                printk(KERN_ERR "Error: couldn't register serial driver\n");

        for (channel = 0; channel < zs_channels_found; ++channel) {
#ifdef CONFIG_KGDB
                if (zs_soft[channel].kgdb_channel) {
                        kgdb_interruptible(1);
                        continue;
                }
#endif
                zs_soft[channel].clk_divisor = 16;
/* -- we are not sure the SCC is powered ON at this point
                zs_soft[channel].zs_baud = get_zsbaud(&zs_soft[channel]);
*/
                zs_soft[channel].zs_baud = 38400;

                /* If console serial line, then enable interrupts. */
                if (zs_soft[channel].is_cons) {
                        printk(KERN_INFO "macserial: console line, enabling "
                                        "interrupt %d\n", zs_soft[channel].irq);
                        panic("macserial: console not supported yet !");
                        write_zsreg(zs_soft[channel].zs_channel, R1,
                                    (EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB));
                        write_zsreg(zs_soft[channel].zs_channel, R9,
                                    (NV | MIE));
                }
        }

        for (info = zs_chain, i = 0; info; info = info->zs_next, i++)
        {
                unsigned char* connector;
                int lenp;

#ifdef CONFIG_KGDB
                if (info->kgdb_channel) {
                        continue;
                }
#endif
                info->magic = SERIAL_MAGIC;
                info->port = (int) info->zs_channel->control;
                info->line = i;
                info->tty = 0;
                info->custom_divisor = 16;
                info->timeout = 0;
                info->close_delay = 50;
                info->closing_wait = 3000;
                info->x_char = 0;
                info->event = 0;
                info->count = 0;
                info->blocked_open = 0;
                INIT_WORK(&info->tqueue, do_softint, info);
                spin_lock_init(&info->lock);
                init_waitqueue_head(&info->open_wait);
                init_waitqueue_head(&info->close_wait);
                info->timeout = HZ;
                printk(KERN_INFO "tty%02d at 0x%08x (irq = %d)", info->line, 
                        info->port, info->irq);
                printk(" is a Z8530 ESCC");
                connector = get_property(info->dev_node, "AAPL,connector", &lenp);
                if (connector)
                        printk(", port = %s", connector);
                if (info->is_internal_modem)
                        printk(" (internal modem)");
                if (info->is_irda)
                        printk(" (IrDA)");
                printk("\n");
        }
        tmp_buf = 0;

        return 0;
}

void macserial_cleanup(void)
{
        int i;
        unsigned long flags;
        struct mac_serial *info;

        for (info = zs_chain, i = 0; info; info = info->zs_next, i++)
                set_scc_power(info, 0);
        spin_lock_irqsave(&info->lock, flags);
        for (i = 0; i < zs_channels_found; ++i) {
                free_irq(zs_soft[i].irq, &zs_soft[i]);
                if (zs_soft[i].has_dma) {
                        free_irq(zs_soft[i].tx_dma_irq, &zs_soft[i]);
                        free_irq(zs_soft[i].rx_dma_irq, &zs_soft[i]);
                }
                release_OF_resource(zs_soft[i].dev_node, 0);
                if (zs_soft[i].has_dma) {
                        struct device_node* ch = zs_soft[i].dev_node;
                        release_OF_resource(ch, ch->n_addrs - 2);
                        release_OF_resource(ch, ch->n_addrs - 1);
                }
        }
        spin_unlock_irqrestore(&info->lock, flags);
        tty_unregister_driver(serial_driver);
        put_tty_driver(serial_driver);

        if (tmp_buf) {
                free_page((unsigned long) tmp_buf);
                tmp_buf = 0;
        }

#ifdef CONFIG_PMAC_PBOOK
        if (zs_channels_found)
                pmu_unregister_sleep_notifier(&serial_sleep_notifier);
#endif /* CONFIG_PMAC_PBOOK */
}

module_init(macserial_init);
module_exit(macserial_cleanup);
MODULE_LICENSE("GPL");

#if 0
/*
 * register_serial and unregister_serial allows for serial ports to be
 * configured at run-time, to support PCMCIA modems.
 */
/* PowerMac: Unused at this time, just here to make things link. */
int register_serial(struct serial_struct *req)
{
        return -1;
}

void unregister_serial(int line)
{
        return;
}
#endif

/*
 * ------------------------------------------------------------
 * Serial console driver
 * ------------------------------------------------------------
 */
#ifdef CONFIG_SERIAL_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 mac_serial *info = zs_soft + co->index;
        int i;

        /* Turn of interrupts and enable the transmitter. */
        write_zsreg(info->zs_channel, R1, info->curregs[1] & ~TxINT_ENAB);
        write_zsreg(info->zs_channel, R5, info->curregs[5] | TxENAB | RTS | DTR);

        for (i=0; i<count; i++) {
                /* Wait for the transmit buffer to empty. */
                while ((read_zsreg(info->zs_channel, 0) & Tx_BUF_EMP) == 0) {
                        eieio();
                }

                write_zsdata(info->zs_channel, s[i]);
                if (s[i] == 10) {
                        while ((read_zsreg(info->zs_channel, 0) & Tx_BUF_EMP)
                                == 0)
                                eieio();

                        write_zsdata(info->zs_channel, 13);
                }
        }

        /* Restore the values in the registers. */
        write_zsreg(info->zs_channel, R1, info->curregs[1]);
        /* Don't disable the transmitter. */
}

static struct tty_driver *serial_driver;

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 mac_serial *info;
        int     baud = 38400;
        int     bits = 8;
        int     parity = 'n';
        int     cflag = CREAD | HUPCL | CLOCAL;
        int     brg;
        char    *s;
        long    flags;

        /* Find out how many Z8530 SCCs we have */
        if (zs_chain == 0)
                probe_sccs();

        if (zs_chain == 0)
                return -1;

        /* Do we have the device asked for? */
        if (co->index >= zs_channels_found)
                return -1;
        info = zs_soft + co->index;

        set_scc_power(info, 1);

        /* Reset the channel */
        write_zsreg(info->zs_channel, R9, CHRA);

        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 9600:
                cflag |= B9600;
                break;
        case 19200:
                cflag |= B19200;
                break;
        case 57600:
                cflag |= B57600;
                break;
        case 115200:
                cflag |= B115200;
                break;
        case 38400:
        default:
                cflag |= B38400;
                break;
        }
        switch(bits) {
        case 7:
                cflag |= CS7;
                break;
        default:
        case 8:
                cflag |= CS8;
                break;
        }
        switch(parity) {
        case 'o': case 'O':
                cflag |= PARENB | PARODD;
                break;
        case 'e': case 'E':
                cflag |= PARENB;
                break;
        }
        co->cflag = cflag;

        spin_lock_irqsave(&info->lock, flags);
        memset(info->curregs, 0, sizeof(info->curregs));

        info->zs_baud = baud;
        info->clk_divisor = 16;
        switch (info->zs_baud) {
        case ZS_CLOCK/16:       /* 230400 */
                info->curregs[4] = X16CLK;
                info->curregs[11] = 0;
                break;
        case ZS_CLOCK/32:       /* 115200 */
                info->curregs[4] = X32CLK;
                info->curregs[11] = 0;
                break;
        default:
                info->curregs[4] = X16CLK;
                info->curregs[11] = TCBR | RCBR;
                brg = BPS_TO_BRG(info->zs_baud, ZS_CLOCK/info->clk_divisor);
                info->curregs[12] = (brg & 255);
                info->curregs[13] = ((brg >> 8) & 255);
                info->curregs[14] = BRENABL;
        }

        /* byte size and parity */
        info->curregs[3] &= ~RxNBITS_MASK;
        info->curregs[5] &= ~TxNBITS_MASK;
        switch (cflag & CSIZE) {
        case CS5:
                info->curregs[3] |= Rx5;
                info->curregs[5] |= Tx5;
                break;
        case CS6:
                info->curregs[3] |= Rx6;
                info->curregs[5] |= Tx6;
                break;
        case CS7:
                info->curregs[3] |= Rx7;
                info->curregs[5] |= Tx7;
                break;
        case CS8:
        default: /* defaults to 8 bits */
                info->curregs[3] |= Rx8;
                info->curregs[5] |= Tx8;
                break;
        }
        info->curregs[5] |= TxENAB | RTS | DTR;
        info->pendregs[3] = info->curregs[3];
        info->pendregs[5] = info->curregs[5];

        info->curregs[4] &= ~(SB_MASK | PAR_ENA | PAR_EVEN);
        if (cflag & CSTOPB) {
                info->curregs[4] |= SB2;
        } else {
                info->curregs[4] |= SB1;
        }
        if (cflag & PARENB) {
                info->curregs[4] |= PAR_ENA;
                if (!(cflag & PARODD)) {
                        info->curregs[4] |= PAR_EVEN;
                }
        }
        info->pendregs[4] = info->curregs[4];

        if (!(cflag & CLOCAL)) {
                if (!(info->curregs[15] & DCDIE))
                        info->read_reg_zero = read_zsreg(info->zs_channel, 0);
                info->curregs[15] |= DCDIE;
        } else
                info->curregs[15] &= ~DCDIE;
        if (cflag & CRTSCTS) {
                info->curregs[15] |= CTSIE;
                if ((read_zsreg(info->zs_channel, 0) & CTS) != 0)
                        info->tx_stopped = 1;
        } else {
                info->curregs[15] &= ~CTSIE;
                info->tx_stopped = 0;
        }
        info->pendregs[15] = info->curregs[15];

        /* Load up the new values */
        load_zsregs(info->zs_channel, info->curregs);

        spin_unlock_irqrestore(&info->lock, 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.
 */
static void __init mac_scc_console_init(void)
{
        register_console(&sercons);
}
console_initcall(mac_scc_console_init);

#endif /* ifdef CONFIG_SERIAL_CONSOLE */

#ifdef CONFIG_KGDB
/* These are for receiving and sending characters under the kgdb
 * source level kernel debugger.
 */
void putDebugChar(char kgdb_char)
{
        struct mac_zschannel *chan = zs_kgdbchan;
        while ((read_zsreg(chan, 0) & Tx_BUF_EMP) == 0)
                udelay(5);
        write_zsdata(chan, kgdb_char);
}

char getDebugChar(void)
{
        struct mac_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 mac_zschannel *chan = zs_kgdbchan;
        int one, nine;
        nine = read_zsreg(chan, 9);
        if (yes == 1) {
                one = EXT_INT_ENAB|INT_ALL_Rx;
                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);
}

/* 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 mac_zschannel *ms, int intson, int bps)
{
        int brg;
        int i, x;
        volatile char *sccc = ms->control;
        brg = BPS_TO_BRG(bps, ZS_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.
 * XXX at the moment probably only channel A will work
 */
void __init zs_kgdb_hook(int tty_num)
{
        /* Find out how many Z8530 SCCs we have */
        if (zs_chain == 0)
                probe_sccs();

        set_scc_power(&zs_soft[tty_num], 1);

        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].kgdb_channel = 1;     /* 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 */

#ifdef CONFIG_PMAC_PBOOK
/*
 * notify clients before sleep and reset bus afterwards
 */
int
serial_notify_sleep(struct pmu_sleep_notifier *self, int when)
{
        int i;

        switch (when) {
        case PBOOK_SLEEP_REQUEST:
        case PBOOK_SLEEP_REJECT:
                break;

        case PBOOK_SLEEP_NOW:
                for (i=0; i<zs_channels_found; i++) {
                        struct mac_serial *info = &zs_soft[i];
                        if (info->flags & ZILOG_INITIALIZED) {
                                shutdown(info);
                                info->flags |= ZILOG_SLEEPING;
                        }
                }
                break;
        case PBOOK_WAKE:
                for (i=0; i<zs_channels_found; i++) {
                        struct mac_serial *info = &zs_soft[i];
                        if (info->flags & ZILOG_SLEEPING) {
                                info->flags &= ~ZILOG_SLEEPING;
                                startup(info);
                        }
                }
                break;
        }
        return PBOOK_SLEEP_OK;
}
#endif /* CONFIG_PMAC_PBOOK */