// SPDX-License-Identifier: GPL-2.0
/* sunzilog.c: Zilog serial driver for Sparc systems.
 *
 * Driver for Zilog serial chips found on Sun workstations and
 * servers.  This driver could actually be made more generic.
 *
 * This is based on the old drivers/sbus/char/zs.c code.  A lot
 * of code has been simply moved over directly from there but
 * much has been rewritten.  Credits therefore go out to Eddie
 * C. Dost, Pete Zaitcev, Ted Ts'o and Alex Buell for their
 * work there.
 *
 * Copyright (C) 2002, 2006, 2007 David S. Miller (davem@davemloft.net)
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/circ_buf.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/spinlock.h>
#ifdef CONFIG_SERIO
#include <linux/serio.h>
#endif
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#include <linux/io.h>
#include <asm/irq.h>
#include <asm/setup.h>

#include <linux/serial_core.h>
#include <linux/sunserialcore.h>

#include "sunzilog.h"

/* On 32-bit sparcs we need to delay after register accesses
 * to accommodate sun4 systems, but we do not need to flush writes.
 * On 64-bit sparc we only need to flush single writes to ensure
 * completion.
 */
#ifndef CONFIG_SPARC64
#define ZSDELAY()               udelay(5)
#define ZSDELAY_LONG()          udelay(20)
#define ZS_WSYNC(channel)       do { } while (0)
#else
#define ZSDELAY()
#define ZSDELAY_LONG()
#define ZS_WSYNC(__channel) \
        readb(&((__channel)->control))
#endif

#define ZS_CLOCK                4915200 /* Zilog input clock rate. */
#define ZS_CLOCK_DIVISOR        16      /* Divisor this driver uses. */

/*
 * We wrap our port structure around the generic uart_port.
 */
struct uart_sunzilog_port {
        struct uart_port                port;

        /* IRQ servicing chain.  */
        struct uart_sunzilog_port       *next;

        /* Current values of Zilog write registers.  */
        unsigned char                   curregs[NUM_ZSREGS];

        unsigned int                    flags;
#define SUNZILOG_FLAG_CONS_KEYB         0x00000001
#define SUNZILOG_FLAG_CONS_MOUSE        0x00000002
#define SUNZILOG_FLAG_IS_CONS           0x00000004
#define SUNZILOG_FLAG_IS_KGDB           0x00000008
#define SUNZILOG_FLAG_MODEM_STATUS      0x00000010
#define SUNZILOG_FLAG_IS_CHANNEL_A      0x00000020
#define SUNZILOG_FLAG_REGS_HELD         0x00000040
#define SUNZILOG_FLAG_TX_STOPPED        0x00000080
#define SUNZILOG_FLAG_TX_ACTIVE         0x00000100
#define SUNZILOG_FLAG_ESCC              0x00000200
#define SUNZILOG_FLAG_ISR_HANDLER       0x00000400

        unsigned int cflag;

        unsigned char                   parity_mask;
        unsigned char                   prev_status;

#ifdef CONFIG_SERIO
        struct serio                    serio;
        int                             serio_open;
#endif
};

static void sunzilog_putchar(struct uart_port *port, unsigned char ch);

#define ZILOG_CHANNEL_FROM_PORT(PORT)   ((struct zilog_channel __iomem *)((PORT)->membase))
#define UART_ZILOG(PORT)                ((struct uart_sunzilog_port *)(PORT))

#define ZS_IS_KEYB(UP)  ((UP)->flags & SUNZILOG_FLAG_CONS_KEYB)
#define ZS_IS_MOUSE(UP) ((UP)->flags & SUNZILOG_FLAG_CONS_MOUSE)
#define ZS_IS_CONS(UP)  ((UP)->flags & SUNZILOG_FLAG_IS_CONS)
#define ZS_IS_KGDB(UP)  ((UP)->flags & SUNZILOG_FLAG_IS_KGDB)
#define ZS_WANTS_MODEM_STATUS(UP)       ((UP)->flags & SUNZILOG_FLAG_MODEM_STATUS)
#define ZS_IS_CHANNEL_A(UP)     ((UP)->flags & SUNZILOG_FLAG_IS_CHANNEL_A)
#define ZS_REGS_HELD(UP)        ((UP)->flags & SUNZILOG_FLAG_REGS_HELD)
#define ZS_TX_STOPPED(UP)       ((UP)->flags & SUNZILOG_FLAG_TX_STOPPED)
#define ZS_TX_ACTIVE(UP)        ((UP)->flags & SUNZILOG_FLAG_TX_ACTIVE)

/* Reading and writing Zilog8530 registers.  The delays are to make this
 * driver work on the Sun4 which needs a settling delay after each chip
 * register access, other machines handle this in hardware via auxiliary
 * flip-flops which implement the settle time we do in software.
 *
 * The port lock must be held and local IRQs must be disabled
 * when {read,write}_zsreg is invoked.
 */
static unsigned char read_zsreg(struct zilog_channel __iomem *channel,
                                unsigned char reg)
{
        unsigned char retval;

        writeb(reg, &channel->control);
        ZSDELAY();
        retval = readb(&channel->control);
        ZSDELAY();

        return retval;
}

static void write_zsreg(struct zilog_channel __iomem *channel,
                        unsigned char reg, unsigned char value)
{
        writeb(reg, &channel->control);
        ZSDELAY();
        writeb(value, &channel->control);
        ZSDELAY();
}

static void sunzilog_clear_fifo(struct zilog_channel __iomem *channel)
{
        int i;

        for (i = 0; i < 32; i++) {
                unsigned char regval;

                regval = readb(&channel->control);
                ZSDELAY();
                if (regval & Rx_CH_AV)
                        break;

                regval = read_zsreg(channel, R1);
                readb(&channel->data);
                ZSDELAY();

                if (regval & (PAR_ERR | Rx_OVR | CRC_ERR)) {
                        writeb(ERR_RES, &channel->control);
                        ZSDELAY();
                        ZS_WSYNC(channel);
                }
        }
}

/* This function must only be called when the TX is not busy.  The UART
 * port lock must be held and local interrupts disabled.
 */
static int __load_zsregs(struct zilog_channel __iomem *channel, unsigned char *regs)
{
        int i;
        int escc;
        unsigned char r15;

        /* Let pending transmits finish.  */
        for (i = 0; i < 1000; i++) {
                unsigned char stat = read_zsreg(channel, R1);
                if (stat & ALL_SNT)
                        break;
                udelay(100);
        }

        writeb(ERR_RES, &channel->control);
        ZSDELAY();
        ZS_WSYNC(channel);

        sunzilog_clear_fifo(channel);

        /* Disable all interrupts.  */
        write_zsreg(channel, R1,
                    regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));

        /* Set parity, sync config, stop bits, and clock divisor.  */
        write_zsreg(channel, R4, regs[R4]);

        /* Set misc. TX/RX control bits.  */
        write_zsreg(channel, R10, regs[R10]);

        /* Set TX/RX controls sans the enable bits.  */
        write_zsreg(channel, R3, regs[R3] & ~RxENAB);
        write_zsreg(channel, R5, regs[R5] & ~TxENAB);

        /* Synchronous mode config.  */
        write_zsreg(channel, R6, regs[R6]);
        write_zsreg(channel, R7, regs[R7]);

        /* Don't mess with the interrupt vector (R2, unused by us) and
         * master interrupt control (R9).  We make sure this is setup
         * properly at probe time then never touch it again.
         */

        /* Disable baud generator.  */
        write_zsreg(channel, R14, regs[R14] & ~BRENAB);

        /* Clock mode control.  */
        write_zsreg(channel, R11, regs[R11]);

        /* Lower and upper byte of baud rate generator divisor.  */
        write_zsreg(channel, R12, regs[R12]);
        write_zsreg(channel, R13, regs[R13]);
        
        /* Now rewrite R14, with BRENAB (if set).  */
        write_zsreg(channel, R14, regs[R14]);

        /* External status interrupt control.  */
        write_zsreg(channel, R15, (regs[R15] | WR7pEN) & ~FIFOEN);

        /* ESCC Extension Register */
        r15 = read_zsreg(channel, R15);
        if (r15 & 0x01) {
                write_zsreg(channel, R7,  regs[R7p]);

                /* External status interrupt and FIFO control.  */
                write_zsreg(channel, R15, regs[R15] & ~WR7pEN);
                escc = 1;
        } else {
                 /* Clear FIFO bit case it is an issue */
                regs[R15] &= ~FIFOEN;
                escc = 0;
        }

        /* Reset external status interrupts.  */
        write_zsreg(channel, R0, RES_EXT_INT); /* First Latch  */
        write_zsreg(channel, R0, RES_EXT_INT); /* Second Latch */

        /* Rewrite R3/R5, this time without enables masked.  */
        write_zsreg(channel, R3, regs[R3]);
        write_zsreg(channel, R5, regs[R5]);

        /* Rewrite R1, this time without IRQ enabled masked.  */
        write_zsreg(channel, R1, regs[R1]);

        return escc;
}

/* Reprogram the Zilog channel HW registers with the copies found in the
 * software state struct.  If the transmitter is busy, we defer this update
 * until the next TX complete interrupt.  Else, we do it right now.
 *
 * The UART port lock must be held and local interrupts disabled.
 */
static void sunzilog_maybe_update_regs(struct uart_sunzilog_port *up,
                                       struct zilog_channel __iomem *channel)
{
        if (!ZS_REGS_HELD(up)) {
                if (ZS_TX_ACTIVE(up)) {
                        up->flags |= SUNZILOG_FLAG_REGS_HELD;
                } else {
                        __load_zsregs(channel, up->curregs);
                }
        }
}

static void sunzilog_change_mouse_baud(struct uart_sunzilog_port *up)
{
        unsigned int cur_cflag = up->cflag;
        int brg, new_baud;

        up->cflag &= ~CBAUD;
        up->cflag |= suncore_mouse_baud_cflag_next(cur_cflag, &new_baud);

        brg = BPS_TO_BRG(new_baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
        up->curregs[R12] = (brg & 0xff);
        up->curregs[R13] = (brg >> 8) & 0xff;
        sunzilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(&up->port));
}

static void sunzilog_kbdms_receive_chars(struct uart_sunzilog_port *up,
                                         unsigned char ch, int is_break)
{
        if (ZS_IS_KEYB(up)) {
                /* Stop-A is handled by drivers/char/keyboard.c now. */
#ifdef CONFIG_SERIO
                if (up->serio_open)
                        serio_interrupt(&up->serio, ch, 0);
#endif
        } else if (ZS_IS_MOUSE(up)) {
                int ret = suncore_mouse_baud_detection(ch, is_break);

                switch (ret) {
                case 2:
                        sunzilog_change_mouse_baud(up);
                        fallthrough;
                case 1:
                        break;

                case 0:
#ifdef CONFIG_SERIO
                        if (up->serio_open)
                                serio_interrupt(&up->serio, ch, 0);
#endif
                        break;
                }
        }
}

static struct tty_port *
sunzilog_receive_chars(struct uart_sunzilog_port *up,
                       struct zilog_channel __iomem *channel)
{
        struct tty_port *port = NULL;
        unsigned char ch, r1, flag;

        if (up->port.state != NULL)             /* Unopened serial console */
                port = &up->port.state->port;

        for (;;) {

                r1 = read_zsreg(channel, R1);
                if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
                        writeb(ERR_RES, &channel->control);
                        ZSDELAY();
                        ZS_WSYNC(channel);
                }

                ch = readb(&channel->control);
                ZSDELAY();

                /* This funny hack depends upon BRK_ABRT not interfering
                 * with the other bits we care about in R1.
                 */
                if (ch & BRK_ABRT)
                        r1 |= BRK_ABRT;

                if (!(ch & Rx_CH_AV))
                        break;

                ch = readb(&channel->data);
                ZSDELAY();

                ch &= up->parity_mask;

                if (unlikely(ZS_IS_KEYB(up)) || unlikely(ZS_IS_MOUSE(up))) {
                        sunzilog_kbdms_receive_chars(up, ch, 0);
                        continue;
                }

                /* A real serial line, record the character and status.  */
                flag = TTY_NORMAL;
                up->port.icount.rx++;
                if (r1 & (BRK_ABRT | PAR_ERR | Rx_OVR | CRC_ERR)) {
                        if (r1 & BRK_ABRT) {
                                r1 &= ~(PAR_ERR | CRC_ERR);
                                up->port.icount.brk++;
                                if (uart_handle_break(&up->port))
                                        continue;
                        }
                        else if (r1 & PAR_ERR)
                                up->port.icount.parity++;
                        else if (r1 & CRC_ERR)
                                up->port.icount.frame++;
                        if (r1 & Rx_OVR)
                                up->port.icount.overrun++;
                        r1 &= up->port.read_status_mask;
                        if (r1 & BRK_ABRT)
                                flag = TTY_BREAK;
                        else if (r1 & PAR_ERR)
                                flag = TTY_PARITY;
                        else if (r1 & CRC_ERR)
                                flag = TTY_FRAME;
                }
                if (uart_handle_sysrq_char(&up->port, ch) || !port)
                        continue;

                if (up->port.ignore_status_mask == 0xff ||
                    (r1 & up->port.ignore_status_mask) == 0) {
                        tty_insert_flip_char(port, ch, flag);
                }
                if (r1 & Rx_OVR)
                        tty_insert_flip_char(port, 0, TTY_OVERRUN);
        }

        return port;
}

static void sunzilog_status_handle(struct uart_sunzilog_port *up,
                                   struct zilog_channel __iomem *channel)
{
        unsigned char status;

        status = readb(&channel->control);
        ZSDELAY();

        writeb(RES_EXT_INT, &channel->control);
        ZSDELAY();
        ZS_WSYNC(channel);

        if (status & BRK_ABRT) {
                if (ZS_IS_MOUSE(up))
                        sunzilog_kbdms_receive_chars(up, 0, 1);
                if (ZS_IS_CONS(up)) {
                        /* Wait for BREAK to deassert to avoid potentially
                         * confusing the PROM.
                         */
                        while (1) {
                                status = readb(&channel->control);
                                ZSDELAY();
                                if (!(status & BRK_ABRT))
                                        break;
                        }
                        sun_do_break();
                        return;
                }
        }

        if (ZS_WANTS_MODEM_STATUS(up)) {
                if (status & SYNC)
                        up->port.icount.dsr++;

                /* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
                 * But it does not tell us which bit has changed, we have to keep
                 * track of this ourselves.
                 */
                if ((status ^ up->prev_status) ^ DCD)
                        uart_handle_dcd_change(&up->port,
                                               (status & DCD));
                if ((status ^ up->prev_status) ^ CTS)
                        uart_handle_cts_change(&up->port,
                                               (status & CTS));

                wake_up_interruptible(&up->port.state->port.delta_msr_wait);
        }

        up->prev_status = status;
}

static void sunzilog_transmit_chars(struct uart_sunzilog_port *up,
                                    struct zilog_channel __iomem *channel)
{
        struct tty_port *tport;
        unsigned char ch;

        if (ZS_IS_CONS(up)) {
                unsigned char status = readb(&channel->control);
                ZSDELAY();

                /* TX still busy?  Just wait for the next TX done interrupt.
                 *
                 * It can occur because of how we do serial console writes.  It would
                 * be nice to transmit console writes just like we normally would for
                 * a TTY line. (ie. buffered and TX interrupt driven).  That is not
                 * easy because console writes cannot sleep.  One solution might be
                 * to poll on enough port->xmit space becoming free.  -DaveM
                 */
                if (!(status & Tx_BUF_EMP))
                        return;
        }

        up->flags &= ~SUNZILOG_FLAG_TX_ACTIVE;

        if (ZS_REGS_HELD(up)) {
                __load_zsregs(channel, up->curregs);
                up->flags &= ~SUNZILOG_FLAG_REGS_HELD;
        }

        if (ZS_TX_STOPPED(up)) {
                up->flags &= ~SUNZILOG_FLAG_TX_STOPPED;
                goto ack_tx_int;
        }

        if (up->port.x_char) {
                up->flags |= SUNZILOG_FLAG_TX_ACTIVE;
                writeb(up->port.x_char, &channel->data);
                ZSDELAY();
                ZS_WSYNC(channel);

                up->port.icount.tx++;
                up->port.x_char = 0;
                return;
        }

        if (up->port.state == NULL)
                goto ack_tx_int;
        tport = &up->port.state->port;

        if (uart_tx_stopped(&up->port))
                goto ack_tx_int;

        if (!uart_fifo_get(&up->port, &ch))
                goto ack_tx_int;

        up->flags |= SUNZILOG_FLAG_TX_ACTIVE;
        writeb(ch, &channel->data);
        ZSDELAY();
        ZS_WSYNC(channel);

        if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
                uart_write_wakeup(&up->port);

        return;

ack_tx_int:
        writeb(RES_Tx_P, &channel->control);
        ZSDELAY();
        ZS_WSYNC(channel);
}

static irqreturn_t sunzilog_interrupt(int irq, void *dev_id)
{
        struct uart_sunzilog_port *up = dev_id;

        while (up) {
                struct zilog_channel __iomem *channel
                        = ZILOG_CHANNEL_FROM_PORT(&up->port);
                struct tty_port *port;
                unsigned char r3;

                uart_port_lock(&up->port);
                r3 = read_zsreg(channel, R3);

                /* Channel A */
                port = NULL;
                if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
                        writeb(RES_H_IUS, &channel->control);
                        ZSDELAY();
                        ZS_WSYNC(channel);

                        if (r3 & CHARxIP)
                                port = sunzilog_receive_chars(up, channel);
                        if (r3 & CHAEXT)
                                sunzilog_status_handle(up, channel);
                        if (r3 & CHATxIP)
                                sunzilog_transmit_chars(up, channel);
                }
                uart_port_unlock(&up->port);

                if (port)
                        tty_flip_buffer_push(port);

                /* Channel B */
                up = up->next;
                channel = ZILOG_CHANNEL_FROM_PORT(&up->port);

                uart_port_lock(&up->port);
                port = NULL;
                if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
                        writeb(RES_H_IUS, &channel->control);
                        ZSDELAY();
                        ZS_WSYNC(channel);

                        if (r3 & CHBRxIP)
                                port = sunzilog_receive_chars(up, channel);
                        if (r3 & CHBEXT)
                                sunzilog_status_handle(up, channel);
                        if (r3 & CHBTxIP)
                                sunzilog_transmit_chars(up, channel);
                }
                uart_port_unlock(&up->port);

                if (port)
                        tty_flip_buffer_push(port);

                up = up->next;
        }

        return IRQ_HANDLED;
}

/* A convenient way to quickly get R0 status.  The caller must _not_ hold the
 * port lock, it is acquired here.
 */
static __inline__ unsigned char sunzilog_read_channel_status(struct uart_port *port)
{
        struct zilog_channel __iomem *channel;
        unsigned char status;

        channel = ZILOG_CHANNEL_FROM_PORT(port);
        status = readb(&channel->control);
        ZSDELAY();

        return status;
}

/* The port lock is not held.  */
static unsigned int sunzilog_tx_empty(struct uart_port *port)
{
        unsigned long flags;
        unsigned char status;
        unsigned int ret;

        uart_port_lock_irqsave(port, &flags);

        status = sunzilog_read_channel_status(port);

        uart_port_unlock_irqrestore(port, flags);

        if (status & Tx_BUF_EMP)
                ret = TIOCSER_TEMT;
        else
                ret = 0;

        return ret;
}

/* The port lock is held and interrupts are disabled.  */
static unsigned int sunzilog_get_mctrl(struct uart_port *port)
{
        unsigned char status;
        unsigned int ret;

        status = sunzilog_read_channel_status(port);

        ret = 0;
        if (status & DCD)
                ret |= TIOCM_CAR;
        if (status & SYNC)
                ret |= TIOCM_DSR;
        if (status & CTS)
                ret |= TIOCM_CTS;

        return ret;
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        struct uart_sunzilog_port *up =
                container_of(port, struct uart_sunzilog_port, port);
        struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
        unsigned char set_bits, clear_bits;

        set_bits = clear_bits = 0;

        if (mctrl & TIOCM_RTS)
                set_bits |= RTS;
        else
                clear_bits |= RTS;
        if (mctrl & TIOCM_DTR)
                set_bits |= DTR;
        else
                clear_bits |= DTR;

        /* NOTE: Not subject to 'transmitter active' rule.  */ 
        up->curregs[R5] |= set_bits;
        up->curregs[R5] &= ~clear_bits;
        write_zsreg(channel, R5, up->curregs[R5]);
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_stop_tx(struct uart_port *port)
{
        struct uart_sunzilog_port *up =
                container_of(port, struct uart_sunzilog_port, port);

        up->flags |= SUNZILOG_FLAG_TX_STOPPED;
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_start_tx(struct uart_port *port)
{
        struct uart_sunzilog_port *up =
                container_of(port, struct uart_sunzilog_port, port);
        struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
        unsigned char status;

        up->flags |= SUNZILOG_FLAG_TX_ACTIVE;
        up->flags &= ~SUNZILOG_FLAG_TX_STOPPED;

        status = readb(&channel->control);
        ZSDELAY();

        /* TX busy?  Just wait for the TX done interrupt.  */
        if (!(status & Tx_BUF_EMP))
                return;

        /* Send the first character to jump-start the TX done
         * IRQ sending engine.
         */
        if (port->x_char) {
                writeb(port->x_char, &channel->data);
                ZSDELAY();
                ZS_WSYNC(channel);

                port->icount.tx++;
                port->x_char = 0;
        } else {
                struct tty_port *tport = &port->state->port;
                unsigned char ch;

                if (!uart_fifo_get(&up->port, &ch))
                        return;
                writeb(ch, &channel->data);
                ZSDELAY();
                ZS_WSYNC(channel);

                if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
                        uart_write_wakeup(&up->port);
        }
}

/* The port lock is held.  */
static void sunzilog_stop_rx(struct uart_port *port)
{
        struct uart_sunzilog_port *up = UART_ZILOG(port);
        struct zilog_channel __iomem *channel;

        if (ZS_IS_CONS(up))
                return;

        channel = ZILOG_CHANNEL_FROM_PORT(port);

        /* Disable all RX interrupts.  */
        up->curregs[R1] &= ~RxINT_MASK;
        sunzilog_maybe_update_regs(up, channel);
}

/* The port lock is held.  */
static void sunzilog_enable_ms(struct uart_port *port)
{
        struct uart_sunzilog_port *up =
                container_of(port, struct uart_sunzilog_port, port);
        struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
        unsigned char new_reg;

        new_reg = up->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
        if (new_reg != up->curregs[R15]) {
                up->curregs[R15] = new_reg;

                /* NOTE: Not subject to 'transmitter active' rule.  */ 
                write_zsreg(channel, R15, up->curregs[R15] & ~WR7pEN);
        }
}

/* The port lock is not held.  */
static void sunzilog_break_ctl(struct uart_port *port, int break_state)
{
        struct uart_sunzilog_port *up =
                container_of(port, struct uart_sunzilog_port, port);
        struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
        unsigned char set_bits, clear_bits, new_reg;
        unsigned long flags;

        set_bits = clear_bits = 0;

        if (break_state)
                set_bits |= SND_BRK;
        else
                clear_bits |= SND_BRK;

        uart_port_lock_irqsave(port, &flags);

        new_reg = (up->curregs[R5] | set_bits) & ~clear_bits;
        if (new_reg != up->curregs[R5]) {
                up->curregs[R5] = new_reg;

                /* NOTE: Not subject to 'transmitter active' rule.  */ 
                write_zsreg(channel, R5, up->curregs[R5]);
        }

        uart_port_unlock_irqrestore(port, flags);
}

static void __sunzilog_startup(struct uart_sunzilog_port *up)
{
        struct zilog_channel __iomem *channel;

        channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
        up->prev_status = readb(&channel->control);

        /* Enable receiver and transmitter.  */
        up->curregs[R3] |= RxENAB;
        up->curregs[R5] |= TxENAB;

        up->curregs[R1] |= EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
        sunzilog_maybe_update_regs(up, channel);
}

static int sunzilog_startup(struct uart_port *port)
{
        struct uart_sunzilog_port *up = UART_ZILOG(port);
        unsigned long flags;

        if (ZS_IS_CONS(up))
                return 0;

        uart_port_lock_irqsave(port, &flags);
        __sunzilog_startup(up);
        uart_port_unlock_irqrestore(port, flags);
        return 0;
}

/*
 * The test for ZS_IS_CONS is explained by the following e-mail:
 *****
 * From: Russell King <rmk@arm.linux.org.uk>
 * Date: Sun, 8 Dec 2002 10:18:38 +0000
 *
 * On Sun, Dec 08, 2002 at 02:43:36AM -0500, Pete Zaitcev wrote:
 * > I boot my 2.5 boxes using "console=ttyS0,9600" argument,
 * > and I noticed that something is not right with reference
 * > counting in this case. It seems that when the console
 * > is open by kernel initially, this is not accounted
 * > as an open, and uart_startup is not called.
 *
 * That is correct.  We are unable to call uart_startup when the serial
 * console is initialised because it may need to allocate memory (as
 * request_irq does) and the memory allocators may not have been
 * initialised.
 *
 * 1. initialise the port into a state where it can send characters in the
 *    console write method.
 *
 * 2. don't do the actual hardware shutdown in your shutdown() method (but
 *    do the normal software shutdown - ie, free irqs etc)
 *****
 */
static void sunzilog_shutdown(struct uart_port *port)
{
        struct uart_sunzilog_port *up = UART_ZILOG(port);
        struct zilog_channel __iomem *channel;
        unsigned long flags;

        if (ZS_IS_CONS(up))
                return;

        uart_port_lock_irqsave(port, &flags);

        channel = ZILOG_CHANNEL_FROM_PORT(port);

        /* Disable receiver and transmitter.  */
        up->curregs[R3] &= ~RxENAB;
        up->curregs[R5] &= ~TxENAB;

        /* Disable all interrupts and BRK assertion.  */
        up->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
        up->curregs[R5] &= ~SND_BRK;
        sunzilog_maybe_update_regs(up, channel);

        uart_port_unlock_irqrestore(port, flags);
}

/* Shared by TTY driver and serial console setup.  The port lock is held
 * and local interrupts are disabled.
 */
static void
sunzilog_convert_to_zs(struct uart_sunzilog_port *up, unsigned int cflag,
                       unsigned int iflag, int brg)
{

        up->curregs[R10] = NRZ;
        up->curregs[R11] = TCBR | RCBR;

        /* Program BAUD and clock source. */
        up->curregs[R4] &= ~XCLK_MASK;
        up->curregs[R4] |= X16CLK;
        up->curregs[R12] = brg & 0xff;
        up->curregs[R13] = (brg >> 8) & 0xff;
        up->curregs[R14] = BRSRC | BRENAB;

        /* Character size, stop bits, and parity. */
        up->curregs[R3] &= ~RxN_MASK;
        up->curregs[R5] &= ~TxN_MASK;
        switch (cflag & CSIZE) {
        case CS5:
                up->curregs[R3] |= Rx5;
                up->curregs[R5] |= Tx5;
                up->parity_mask = 0x1f;
                break;
        case CS6:
                up->curregs[R3] |= Rx6;
                up->curregs[R5] |= Tx6;
                up->parity_mask = 0x3f;
                break;
        case CS7:
                up->curregs[R3] |= Rx7;
                up->curregs[R5] |= Tx7;
                up->parity_mask = 0x7f;
                break;
        case CS8:
        default:
                up->curregs[R3] |= Rx8;
                up->curregs[R5] |= Tx8;
                up->parity_mask = 0xff;
                break;
        }
        up->curregs[R4] &= ~0x0c;
        if (cflag & CSTOPB)
                up->curregs[R4] |= SB2;
        else
                up->curregs[R4] |= SB1;
        if (cflag & PARENB)
                up->curregs[R4] |= PAR_ENAB;
        else
                up->curregs[R4] &= ~PAR_ENAB;
        if (!(cflag & PARODD))
                up->curregs[R4] |= PAR_EVEN;
        else
                up->curregs[R4] &= ~PAR_EVEN;

        up->port.read_status_mask = Rx_OVR;
        if (iflag & INPCK)
                up->port.read_status_mask |= CRC_ERR | PAR_ERR;
        if (iflag & (IGNBRK | BRKINT | PARMRK))
                up->port.read_status_mask |= BRK_ABRT;

        up->port.ignore_status_mask = 0;
        if (iflag & IGNPAR)
                up->port.ignore_status_mask |= CRC_ERR | PAR_ERR;
        if (iflag & IGNBRK) {
                up->port.ignore_status_mask |= BRK_ABRT;
                if (iflag & IGNPAR)
                        up->port.ignore_status_mask |= Rx_OVR;
        }

        if ((cflag & CREAD) == 0)
                up->port.ignore_status_mask = 0xff;
}

/* The port lock is not held.  */
static void
sunzilog_set_termios(struct uart_port *port, struct ktermios *termios,
                     const struct ktermios *old)
{
        struct uart_sunzilog_port *up =
                container_of(port, struct uart_sunzilog_port, port);
        unsigned long flags;
        int baud, brg;

        baud = uart_get_baud_rate(port, termios, old, 1200, 76800);

        uart_port_lock_irqsave(&up->port, &flags);

        brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);

        sunzilog_convert_to_zs(up, termios->c_cflag, termios->c_iflag, brg);

        if (UART_ENABLE_MS(&up->port, termios->c_cflag))
                up->flags |= SUNZILOG_FLAG_MODEM_STATUS;
        else
                up->flags &= ~SUNZILOG_FLAG_MODEM_STATUS;

        up->cflag = termios->c_cflag;

        sunzilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port));

        uart_update_timeout(port, termios->c_cflag, baud);

        uart_port_unlock_irqrestore(&up->port, flags);
}

static const char *sunzilog_type(struct uart_port *port)
{
        struct uart_sunzilog_port *up = UART_ZILOG(port);

        return (up->flags & SUNZILOG_FLAG_ESCC) ? "zs (ESCC)" : "zs";
}

/* We do not request/release mappings of the registers here, this
 * happens at early serial probe time.
 */
static void sunzilog_release_port(struct uart_port *port)
{
}

static int sunzilog_request_port(struct uart_port *port)
{
        return 0;
}

/* These do not need to do anything interesting either.  */
static void sunzilog_config_port(struct uart_port *port, int flags)
{
}

/* We do not support letting the user mess with the divisor, IRQ, etc. */
static int sunzilog_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        return -EINVAL;
}

#ifdef CONFIG_CONSOLE_POLL
static int sunzilog_get_poll_char(struct uart_port *port)
{
        unsigned char ch, r1;
        struct uart_sunzilog_port *up =
                container_of(port, struct uart_sunzilog_port, port);
        struct zilog_channel __iomem *channel
                = ZILOG_CHANNEL_FROM_PORT(&up->port);


        r1 = read_zsreg(channel, R1);
        if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
                writeb(ERR_RES, &channel->control);
                ZSDELAY();
                ZS_WSYNC(channel);
        }

        ch = readb(&channel->control);
        ZSDELAY();

        /* This funny hack depends upon BRK_ABRT not interfering
         * with the other bits we care about in R1.
         */
        if (ch & BRK_ABRT)
                r1 |= BRK_ABRT;

        if (!(ch & Rx_CH_AV))
                return NO_POLL_CHAR;

        ch = readb(&channel->data);
        ZSDELAY();

        ch &= up->parity_mask;
        return ch;
}

static void sunzilog_put_poll_char(struct uart_port *port,
                        unsigned char ch)
{
        struct uart_sunzilog_port *up =
                container_of(port, struct uart_sunzilog_port, port);

        sunzilog_putchar(&up->port, ch);
}
#endif /* CONFIG_CONSOLE_POLL */

static const struct uart_ops sunzilog_pops = {
        .tx_empty       =       sunzilog_tx_empty,
        .set_mctrl      =       sunzilog_set_mctrl,
        .get_mctrl      =       sunzilog_get_mctrl,
        .stop_tx        =       sunzilog_stop_tx,
        .start_tx       =       sunzilog_start_tx,
        .stop_rx        =       sunzilog_stop_rx,
        .enable_ms      =       sunzilog_enable_ms,
        .break_ctl      =       sunzilog_break_ctl,
        .startup        =       sunzilog_startup,
        .shutdown       =       sunzilog_shutdown,
        .set_termios    =       sunzilog_set_termios,
        .type           =       sunzilog_type,
        .release_port   =       sunzilog_release_port,
        .request_port   =       sunzilog_request_port,
        .config_port    =       sunzilog_config_port,
        .verify_port    =       sunzilog_verify_port,
#ifdef CONFIG_CONSOLE_POLL
        .poll_get_char  =       sunzilog_get_poll_char,
        .poll_put_char  =       sunzilog_put_poll_char,
#endif
};

static int uart_chip_count;
static struct uart_sunzilog_port *sunzilog_port_table;
static struct zilog_layout __iomem **sunzilog_chip_regs;

static struct uart_sunzilog_port *sunzilog_irq_chain;

static struct uart_driver sunzilog_reg = {
        .owner          =       THIS_MODULE,
        .driver_name    =       "sunzilog",
        .dev_name       =       "ttyS",
        .major          =       TTY_MAJOR,
};

static int __init sunzilog_alloc_tables(int num_sunzilog)
{
        struct uart_sunzilog_port *up;
        unsigned long size;
        int num_channels = num_sunzilog * 2;
        int i;

        size = num_channels * sizeof(struct uart_sunzilog_port);
        sunzilog_port_table = kzalloc(size, GFP_KERNEL);
        if (!sunzilog_port_table)
                return -ENOMEM;

        for (i = 0; i < num_channels; i++) {
                up = &sunzilog_port_table[i];

                spin_lock_init(&up->port.lock);

                if (i == 0)
                        sunzilog_irq_chain = up;

                if (i < num_channels - 1)
                        up->next = up + 1;
                else
                        up->next = NULL;
        }

        size = num_sunzilog * sizeof(struct zilog_layout __iomem *);
        sunzilog_chip_regs = kzalloc(size, GFP_KERNEL);
        if (!sunzilog_chip_regs) {
                kfree(sunzilog_port_table);
                sunzilog_irq_chain = NULL;
                return -ENOMEM;
        }

        return 0;
}

static void sunzilog_free_tables(void)
{
        kfree(sunzilog_port_table);
        sunzilog_irq_chain = NULL;
        kfree(sunzilog_chip_regs);
}

#define ZS_PUT_CHAR_MAX_DELAY   2000    /* 10 ms */

static void __maybe_unused sunzilog_putchar(struct uart_port *port, unsigned char ch)
{
        struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
        int loops = ZS_PUT_CHAR_MAX_DELAY;

        /* This is a timed polling loop so do not switch the explicit
         * udelay with ZSDELAY as that is a NOP on some platforms.  -DaveM
         */
        do {
                unsigned char val = readb(&channel->control);
                if (val & Tx_BUF_EMP) {
                        ZSDELAY();
                        break;
                }
                udelay(5);
        } while (--loops);

        writeb(ch, &channel->data);
        ZSDELAY();
        ZS_WSYNC(channel);
}

#ifdef CONFIG_SERIO

static DEFINE_SPINLOCK(sunzilog_serio_lock);

static int sunzilog_serio_write(struct serio *serio, unsigned char ch)
{
        struct uart_sunzilog_port *up = serio->port_data;
        unsigned long flags;

        spin_lock_irqsave(&sunzilog_serio_lock, flags);

        sunzilog_putchar(&up->port, ch);

        spin_unlock_irqrestore(&sunzilog_serio_lock, flags);

        return 0;
}

static int sunzilog_serio_open(struct serio *serio)
{
        struct uart_sunzilog_port *up = serio->port_data;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&sunzilog_serio_lock, flags);
        if (!up->serio_open) {
                up->serio_open = 1;
                ret = 0;
        } else
                ret = -EBUSY;
        spin_unlock_irqrestore(&sunzilog_serio_lock, flags);

        return ret;
}

static void sunzilog_serio_close(struct serio *serio)
{
        struct uart_sunzilog_port *up = serio->port_data;
        unsigned long flags;

        spin_lock_irqsave(&sunzilog_serio_lock, flags);
        up->serio_open = 0;
        spin_unlock_irqrestore(&sunzilog_serio_lock, flags);
}

#endif /* CONFIG_SERIO */

#ifdef CONFIG_SERIAL_SUNZILOG_CONSOLE
static void
sunzilog_console_write(struct console *con, const char *s, unsigned int count)
{
        struct uart_sunzilog_port *up = &sunzilog_port_table[con->index];
        unsigned long flags;
        int locked = 1;

        if (up->port.sysrq || oops_in_progress)
                locked = uart_port_trylock_irqsave(&up->port, &flags);
        else
                uart_port_lock_irqsave(&up->port, &flags);

        uart_console_write(&up->port, s, count, sunzilog_putchar);
        udelay(2);

        if (locked)
                uart_port_unlock_irqrestore(&up->port, flags);
}

static int __init sunzilog_console_setup(struct console *con, char *options)
{
        struct uart_sunzilog_port *up = &sunzilog_port_table[con->index];
        unsigned long flags;
        int baud, brg;

        if (up->port.type != PORT_SUNZILOG)
                return -EINVAL;

        printk(KERN_INFO "Console: ttyS%d (SunZilog zs%d)\n",
               (sunzilog_reg.minor - 64) + con->index, con->index);

        /* Get firmware console settings.  */
        sunserial_console_termios(con, up->port.dev->of_node);

        /* Firmware console speed is limited to 150-->38400 baud so
         * this hackish cflag thing is OK.
         */
        switch (con->cflag & CBAUD) {
        case B150: baud = 150; break;
        case B300: baud = 300; break;
        case B600: baud = 600; break;
        case B1200: baud = 1200; break;
        case B2400: baud = 2400; break;
        case B4800: baud = 4800; break;
        default: case B9600: baud = 9600; break;
        case B19200: baud = 19200; break;
        case B38400: baud = 38400; break;
        }

        brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);

        uart_port_lock_irqsave(&up->port, &flags);

        up->curregs[R15] |= BRKIE;
        sunzilog_convert_to_zs(up, con->cflag, 0, brg);

        sunzilog_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
        __sunzilog_startup(up);

        uart_port_unlock_irqrestore(&up->port, flags);

        return 0;
}

static struct console sunzilog_console_ops = {
        .name   =       "ttyS",
        .write  =       sunzilog_console_write,
        .device =       uart_console_device,
        .setup  =       sunzilog_console_setup,
        .flags  =       CON_PRINTBUFFER,
        .index  =       -1,
        .data   =       &sunzilog_reg,
};

static inline struct console *SUNZILOG_CONSOLE(void)
{
        return &sunzilog_console_ops;
}

#else
#define SUNZILOG_CONSOLE()      (NULL)
#endif

static void sunzilog_init_kbdms(struct uart_sunzilog_port *up)
{
        int baud, brg;

        if (up->flags & SUNZILOG_FLAG_CONS_KEYB) {
                up->cflag = B1200 | CS8 | CLOCAL | CREAD;
                baud = 1200;
        } else {
                up->cflag = B4800 | CS8 | CLOCAL | CREAD;
                baud = 4800;
        }

        up->curregs[R15] |= BRKIE;
        brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
        sunzilog_convert_to_zs(up, up->cflag, 0, brg);
        sunzilog_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
        __sunzilog_startup(up);
}

#ifdef CONFIG_SERIO
static void sunzilog_register_serio(struct uart_sunzilog_port *up)
{
        struct serio *serio = &up->serio;

        serio->port_data = up;

        serio->id.type = SERIO_RS232;
        if (up->flags & SUNZILOG_FLAG_CONS_KEYB) {
                serio->id.proto = SERIO_SUNKBD;
                strscpy(serio->name, "zskbd", sizeof(serio->name));
        } else {
                serio->id.proto = SERIO_SUN;
                serio->id.extra = 1;
                strscpy(serio->name, "zsms", sizeof(serio->name));
        }
        strscpy(serio->phys,
                ((up->flags & SUNZILOG_FLAG_CONS_KEYB) ?
                 "zs/serio0" : "zs/serio1"),
                sizeof(serio->phys));

        serio->write = sunzilog_serio_write;
        serio->open = sunzilog_serio_open;
        serio->close = sunzilog_serio_close;
        serio->dev.parent = up->port.dev;

        serio_register_port(serio);
}
#endif

static void sunzilog_init_hw(struct uart_sunzilog_port *up)
{
        struct zilog_channel __iomem *channel;
        unsigned long flags;
        int baud, brg;

        channel = ZILOG_CHANNEL_FROM_PORT(&up->port);

        uart_port_lock_irqsave(&up->port, &flags);
        if (ZS_IS_CHANNEL_A(up)) {
                write_zsreg(channel, R9, FHWRES);
                ZSDELAY_LONG();
                (void) read_zsreg(channel, R0);
        }

        if (up->flags & (SUNZILOG_FLAG_CONS_KEYB |
                         SUNZILOG_FLAG_CONS_MOUSE)) {
                up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
                up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
                up->curregs[R3] = RxENAB | Rx8;
                up->curregs[R5] = TxENAB | Tx8;
                up->curregs[R6] = 0x00; /* SDLC Address */
                up->curregs[R7] = 0x7E; /* SDLC Flag    */
                up->curregs[R9] = NV;
                up->curregs[R7p] = 0x00;
                sunzilog_init_kbdms(up);
                /* Only enable interrupts if an ISR handler available */
                if (up->flags & SUNZILOG_FLAG_ISR_HANDLER)
                        up->curregs[R9] |= MIE;
                write_zsreg(channel, R9, up->curregs[R9]);
        } else {
                /* Normal serial TTY. */
                up->parity_mask = 0xff;
                up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
                up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
                up->curregs[R3] = RxENAB | Rx8;
                up->curregs[R5] = TxENAB | Tx8;
                up->curregs[R6] = 0x00; /* SDLC Address */
                up->curregs[R7] = 0x7E; /* SDLC Flag    */
                up->curregs[R9] = NV;
                up->curregs[R10] = NRZ;
                up->curregs[R11] = TCBR | RCBR;
                baud = 9600;
                brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
                up->curregs[R12] = (brg & 0xff);
                up->curregs[R13] = (brg >> 8) & 0xff;
                up->curregs[R14] = BRSRC | BRENAB;
                up->curregs[R15] = FIFOEN; /* Use FIFO if on ESCC */
                up->curregs[R7p] = TxFIFO_LVL | RxFIFO_LVL;
                if (__load_zsregs(channel, up->curregs)) {
                        up->flags |= SUNZILOG_FLAG_ESCC;
                }
                /* Only enable interrupts if an ISR handler available */
                if (up->flags & SUNZILOG_FLAG_ISR_HANDLER)
                        up->curregs[R9] |= MIE;
                write_zsreg(channel, R9, up->curregs[R9]);
        }

        uart_port_unlock_irqrestore(&up->port, flags);

#ifdef CONFIG_SERIO
        if (up->flags & (SUNZILOG_FLAG_CONS_KEYB |
                         SUNZILOG_FLAG_CONS_MOUSE))
                sunzilog_register_serio(up);
#endif
}

static int zilog_irq;

static int zs_probe(struct platform_device *op)
{
        static int kbm_inst, uart_inst;
        int inst;
        struct uart_sunzilog_port *up;
        struct zilog_layout __iomem *rp;
        int keyboard_mouse = 0;
        int err;

        if (of_property_present(op->dev.of_node, "keyboard"))
                keyboard_mouse = 1;

        /* uarts must come before keyboards/mice */
        if (keyboard_mouse)
                inst = uart_chip_count + kbm_inst;
        else
                inst = uart_inst;

        sunzilog_chip_regs[inst] = of_ioremap(&op->resource[0], 0,
                                              sizeof(struct zilog_layout),
                                              "zs");
        if (!sunzilog_chip_regs[inst])
                return -ENOMEM;

        rp = sunzilog_chip_regs[inst];

        if (!zilog_irq)
                zilog_irq = op->archdata.irqs[0];

        up = &sunzilog_port_table[inst * 2];

        /* Channel A */
        up[0].port.mapbase = op->resource[0].start + 0x00;
        up[0].port.membase = (void __iomem *) &rp->channelA;
        up[0].port.iotype = UPIO_MEM;
        up[0].port.irq = op->archdata.irqs[0];
        up[0].port.uartclk = ZS_CLOCK;
        up[0].port.fifosize = 1;
        up[0].port.ops = &sunzilog_pops;
        up[0].port.type = PORT_SUNZILOG;
        up[0].port.flags = 0;
        up[0].port.line = (inst * 2) + 0;
        up[0].port.dev = &op->dev;
        up[0].flags |= SUNZILOG_FLAG_IS_CHANNEL_A;
        up[0].port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_SUNZILOG_CONSOLE);
        if (keyboard_mouse)
                up[0].flags |= SUNZILOG_FLAG_CONS_KEYB;
        sunzilog_init_hw(&up[0]);

        /* Channel B */
        up[1].port.mapbase = op->resource[0].start + 0x04;
        up[1].port.membase = (void __iomem *) &rp->channelB;
        up[1].port.iotype = UPIO_MEM;
        up[1].port.irq = op->archdata.irqs[0];
        up[1].port.uartclk = ZS_CLOCK;
        up[1].port.fifosize = 1;
        up[1].port.ops = &sunzilog_pops;
        up[1].port.type = PORT_SUNZILOG;
        up[1].port.flags = 0;
        up[1].port.line = (inst * 2) + 1;
        up[1].port.dev = &op->dev;
        up[1].flags |= 0;
        up[1].port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_SUNZILOG_CONSOLE);
        if (keyboard_mouse)
                up[1].flags |= SUNZILOG_FLAG_CONS_MOUSE;
        sunzilog_init_hw(&up[1]);

        if (!keyboard_mouse) {
                if (sunserial_console_match(SUNZILOG_CONSOLE(), op->dev.of_node,
                                            &sunzilog_reg, up[0].port.line,
                                            false))
                        up->flags |= SUNZILOG_FLAG_IS_CONS;
                err = uart_add_one_port(&sunzilog_reg, &up[0].port);
                if (err) {
                        of_iounmap(&op->resource[0],
                                   rp, sizeof(struct zilog_layout));
                        return err;
                }
                if (sunserial_console_match(SUNZILOG_CONSOLE(), op->dev.of_node,
                                            &sunzilog_reg, up[1].port.line,
                                            false))
                        up->flags |= SUNZILOG_FLAG_IS_CONS;
                err = uart_add_one_port(&sunzilog_reg, &up[1].port);
                if (err) {
                        uart_remove_one_port(&sunzilog_reg, &up[0].port);
                        of_iounmap(&op->resource[0],
                                   rp, sizeof(struct zilog_layout));
                        return err;
                }
                uart_inst++;
        } else {
                printk(KERN_INFO "%s: Keyboard at MMIO 0x%llx (irq = %d) "
                       "is a %s\n",
                       dev_name(&op->dev),
                       (unsigned long long) up[0].port.mapbase,
                       op->archdata.irqs[0], sunzilog_type(&up[0].port));
                printk(KERN_INFO "%s: Mouse at MMIO 0x%llx (irq = %d) "
                       "is a %s\n",
                       dev_name(&op->dev),
                       (unsigned long long) up[1].port.mapbase,
                       op->archdata.irqs[0], sunzilog_type(&up[1].port));
                kbm_inst++;
        }

        platform_set_drvdata(op, &up[0]);

        return 0;
}

static void zs_remove_one(struct uart_sunzilog_port *up)
{
        if (ZS_IS_KEYB(up) || ZS_IS_MOUSE(up)) {
#ifdef CONFIG_SERIO
                serio_unregister_port(&up->serio);
#endif
        } else
                uart_remove_one_port(&sunzilog_reg, &up->port);
}

static void zs_remove(struct platform_device *op)
{
        struct uart_sunzilog_port *up = platform_get_drvdata(op);
        struct zilog_layout __iomem *regs;

        zs_remove_one(&up[0]);
        zs_remove_one(&up[1]);

        regs = sunzilog_chip_regs[up[0].port.line / 2];
        of_iounmap(&op->resource[0], regs, sizeof(struct zilog_layout));
}

static const struct of_device_id zs_match[] = {
        {
                .name = "zs",
        },
        {},
};
MODULE_DEVICE_TABLE(of, zs_match);

static struct platform_driver zs_driver = {
        .driver = {
                .name = "zs",
                .of_match_table = zs_match,
        },
        .probe          = zs_probe,
        .remove         = zs_remove,
};

static int __init sunzilog_init(void)
{
        struct device_node *dp;
        int err;
        int num_keybms = 0;
        int num_sunzilog = 0;

        for_each_node_by_name(dp, "zs") {
                num_sunzilog++;
                if (of_property_present(dp, "keyboard"))
                        num_keybms++;
        }

        if (num_sunzilog) {
                err = sunzilog_alloc_tables(num_sunzilog);
                if (err)
                        goto out;

                uart_chip_count = num_sunzilog - num_keybms;

                err = sunserial_register_minors(&sunzilog_reg,
                                                uart_chip_count * 2);
                if (err)
                        goto out_free_tables;
        }

        err = platform_driver_register(&zs_driver);
        if (err)
                goto out_unregister_uart;

        if (zilog_irq) {
                struct uart_sunzilog_port *up = sunzilog_irq_chain;
                err = request_irq(zilog_irq, sunzilog_interrupt, IRQF_SHARED,
                                  "zs", sunzilog_irq_chain);
                if (err)
                        goto out_unregister_driver;

                /* Enable Interrupts */
                while (up) {
                        struct zilog_channel __iomem *channel;

                        /* printk (KERN_INFO "Enable IRQ for ZILOG Hardware %p\n", up); */
                        channel          = ZILOG_CHANNEL_FROM_PORT(&up->port);
                        up->flags       |= SUNZILOG_FLAG_ISR_HANDLER;
                        up->curregs[R9] |= MIE;
                        write_zsreg(channel, R9, up->curregs[R9]);
                        up = up->next;
                }
        }

out:
        return err;

out_unregister_driver:
        platform_driver_unregister(&zs_driver);

out_unregister_uart:
        if (num_sunzilog) {
                sunserial_unregister_minors(&sunzilog_reg, num_sunzilog);
                sunzilog_reg.cons = NULL;
        }

out_free_tables:
        sunzilog_free_tables();
        goto out;
}

static void __exit sunzilog_exit(void)
{
        platform_driver_unregister(&zs_driver);

        if (zilog_irq) {
                struct uart_sunzilog_port *up = sunzilog_irq_chain;

                /* Disable Interrupts */
                while (up) {
                        struct zilog_channel __iomem *channel;

                        /* printk (KERN_INFO "Disable IRQ for ZILOG Hardware %p\n", up); */
                        channel          = ZILOG_CHANNEL_FROM_PORT(&up->port);
                        up->flags       &= ~SUNZILOG_FLAG_ISR_HANDLER;
                        up->curregs[R9] &= ~MIE;
                        write_zsreg(channel, R9, up->curregs[R9]);
                        up = up->next;
                }

                free_irq(zilog_irq, sunzilog_irq_chain);
                zilog_irq = 0;
        }

        if (sunzilog_reg.nr) {
                sunserial_unregister_minors(&sunzilog_reg, sunzilog_reg.nr);
                sunzilog_free_tables();
        }
}

module_init(sunzilog_init);
module_exit(sunzilog_exit);

MODULE_AUTHOR("David S. Miller");
MODULE_DESCRIPTION("Sun Zilog serial port driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");