// SPDX-License-Identifier: GPL-2.0
/*
 * su.c: Small serial driver for keyboard/mouse interface on sparc32/PCI
 *
 * Copyright (C) 1997  Eddie C. Dost  (ecd@skynet.be)
 * Copyright (C) 1998-1999  Pete Zaitcev   (zaitcev@yahoo.com)
 *
 * This is mainly a variation of 8250.c, credits go to authors mentioned
 * therein.  In fact this driver should be merged into the generic 8250.c
 * infrastructure perhaps using a 8250_sparc.c module.
 *
 * Fixed to use tty_get_baud_rate().
 *   Theodore Ts'o <tytso@mit.edu>, 2001-Oct-12
 *
 * Converted to new 2.5.x UART layer.
 *   David S. Miller (davem@davemloft.net), 2002-Jul-29
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/errno.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/circ_buf.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/slab.h>
#ifdef CONFIG_SERIO
#include <linux/serio.h>
#endif
#include <linux/serial_reg.h>
#include <linux/init.h>
#include <linux/delay.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>

/* We are on a NS PC87303 clocked with 24.0 MHz, which results
 * in a UART clock of 1.8462 MHz.
 */
#define SU_BASE_BAUD    (1846200 / 16)

enum su_type { SU_PORT_NONE, SU_PORT_MS, SU_PORT_KBD, SU_PORT_PORT };
static char *su_typev[] = { "su(???)", "su(mouse)", "su(kbd)", "su(serial)" };

struct serial_uart_config {
        char    *name;
        int     dfl_xmit_fifo_size;
        int     flags;
};

/*
 * Here we define the default xmit fifo size used for each type of UART.
 */
static const struct serial_uart_config uart_config[] = {
        { "unknown",    1,      0 },
        { "8250",       1,      0 },
        { "16450",      1,      0 },
        { "16550",      1,      0 },
        { "16550A",     16,     UART_CLEAR_FIFO | UART_USE_FIFO },
        { "Cirrus",     1,      0 },
        { "ST16650",    1,      UART_CLEAR_FIFO | UART_STARTECH },
        { "ST16650V2",  32,     UART_CLEAR_FIFO | UART_USE_FIFO | UART_STARTECH },
        { "TI16750",    64,     UART_CLEAR_FIFO | UART_USE_FIFO },
        { "Startech",   1,      0 },
        { "16C950/954", 128,    UART_CLEAR_FIFO | UART_USE_FIFO },
        { "ST16654",    64,     UART_CLEAR_FIFO | UART_USE_FIFO | UART_STARTECH },
        { "XR16850",    128,    UART_CLEAR_FIFO | UART_USE_FIFO | UART_STARTECH },
        { "RSA",        2048,   UART_CLEAR_FIFO | UART_USE_FIFO }
};

struct uart_sunsu_port {
        struct uart_port        port;
        unsigned char           acr;
        unsigned char           ier;
        unsigned short          rev;
        unsigned char           lcr;
        unsigned int            lsr_break_flag;
        unsigned int            cflag;

        /* Probing information.  */
        enum su_type            su_type;
        unsigned int            type_probed;    /* XXX Stupid */
        unsigned long           reg_size;

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

static unsigned int serial_in(struct uart_sunsu_port *up, int offset)
{
        offset <<= up->port.regshift;

        switch (up->port.iotype) {
        case UPIO_HUB6:
                outb(up->port.hub6 - 1 + offset, up->port.iobase);
                return inb(up->port.iobase + 1);

        case UPIO_MEM:
                return readb(up->port.membase + offset);

        default:
                return inb(up->port.iobase + offset);
        }
}

static void serial_out(struct uart_sunsu_port *up, int offset, int value)
{
#ifndef CONFIG_SPARC64
        /*
         * MrCoffee has weird schematics: IRQ4 & P10(?) pins of SuperIO are
         * connected with a gate then go to SlavIO. When IRQ4 goes tristated
         * gate outputs a logical one. Since we use level triggered interrupts
         * we have lockup and watchdog reset. We cannot mask IRQ because
         * keyboard shares IRQ with us (Word has it as Bob Smelik's design).
         * This problem is similar to what Alpha people suffer, see
         * 8250_alpha.c.
         */
        if (offset == UART_MCR)
                value |= UART_MCR_OUT2;
#endif
        offset <<= up->port.regshift;

        switch (up->port.iotype) {
        case UPIO_HUB6:
                outb(up->port.hub6 - 1 + offset, up->port.iobase);
                outb(value, up->port.iobase + 1);
                break;

        case UPIO_MEM:
                writeb(value, up->port.membase + offset);
                break;

        default:
                outb(value, up->port.iobase + offset);
        }
}

/*
 * For the 16C950
 */
static void serial_icr_write(struct uart_sunsu_port *up, int offset, int value)
{
        serial_out(up, UART_SCR, offset);
        serial_out(up, UART_ICR, value);
}

#ifdef CONFIG_SERIAL_8250_RSA
/*
 * Attempts to turn on the RSA FIFO.  Returns zero on failure.
 * We set the port uart clock rate if we succeed.
 */
static int __enable_rsa(struct uart_sunsu_port *up)
{
        unsigned char mode;
        int result;

        mode = serial_in(up, UART_RSA_MSR);
        result = mode & UART_RSA_MSR_FIFO;

        if (!result) {
                serial_out(up, UART_RSA_MSR, mode | UART_RSA_MSR_FIFO);
                mode = serial_in(up, UART_RSA_MSR);
                result = mode & UART_RSA_MSR_FIFO;
        }

        if (result)
                up->port.uartclk = SERIAL_RSA_BAUD_BASE * 16;

        return result;
}

static void enable_rsa(struct uart_sunsu_port *up)
{
        if (up->port.type == PORT_RSA) {
                if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
                        uart_port_lock_irq(&up->port);
                        __enable_rsa(up);
                        uart_port_unlock_irq(&up->port);
                }
                if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
                        serial_out(up, UART_RSA_FRR, 0);
        }
}

/*
 * Attempts to turn off the RSA FIFO.  Returns zero on failure.
 * It is unknown why interrupts were disabled in here.  However,
 * the caller is expected to preserve this behaviour by grabbing
 * the spinlock before calling this function.
 */
static void disable_rsa(struct uart_sunsu_port *up)
{
        unsigned char mode;
        int result;

        if (up->port.type == PORT_RSA &&
            up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
                uart_port_lock_irq(&up->port);

                mode = serial_in(up, UART_RSA_MSR);
                result = !(mode & UART_RSA_MSR_FIFO);

                if (!result) {
                        serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
                        mode = serial_in(up, UART_RSA_MSR);
                        result = !(mode & UART_RSA_MSR_FIFO);
                }

                if (result)
                        up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
                uart_port_unlock_irq(&up->port);
        }
}
#endif /* CONFIG_SERIAL_8250_RSA */

static inline void __stop_tx(struct uart_sunsu_port *p)
{
        if (p->ier & UART_IER_THRI) {
                p->ier &= ~UART_IER_THRI;
                serial_out(p, UART_IER, p->ier);
        }
}

static void sunsu_stop_tx(struct uart_port *port)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);

        __stop_tx(up);

        /*
         * We really want to stop the transmitter from sending.
         */
        if (up->port.type == PORT_16C950) {
                up->acr |= UART_ACR_TXDIS;
                serial_icr_write(up, UART_ACR, up->acr);
        }
}

static void sunsu_start_tx(struct uart_port *port)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);

        if (!(up->ier & UART_IER_THRI)) {
                up->ier |= UART_IER_THRI;
                serial_out(up, UART_IER, up->ier);
        }

        /*
         * Re-enable the transmitter if we disabled it.
         */
        if (up->port.type == PORT_16C950 && up->acr & UART_ACR_TXDIS) {
                up->acr &= ~UART_ACR_TXDIS;
                serial_icr_write(up, UART_ACR, up->acr);
        }
}

static void sunsu_stop_rx(struct uart_port *port)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);

        up->ier &= ~UART_IER_RLSI;
        up->port.read_status_mask &= ~UART_LSR_DR;
        serial_out(up, UART_IER, up->ier);
}

static void sunsu_enable_ms(struct uart_port *port)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);
        unsigned long flags;

        uart_port_lock_irqsave(&up->port, &flags);
        up->ier |= UART_IER_MSI;
        serial_out(up, UART_IER, up->ier);
        uart_port_unlock_irqrestore(&up->port, flags);
}

static void
receive_chars(struct uart_sunsu_port *up, unsigned char *status)
{
        struct tty_port *port = &up->port.state->port;
        unsigned char ch, flag;
        int max_count = 256;
        int saw_console_brk = 0;

        do {
                ch = serial_in(up, UART_RX);
                flag = TTY_NORMAL;
                up->port.icount.rx++;

                if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
                                       UART_LSR_FE | UART_LSR_OE))) {
                        /*
                         * For statistics only
                         */
                        if (*status & UART_LSR_BI) {
                                *status &= ~(UART_LSR_FE | UART_LSR_PE);
                                up->port.icount.brk++;
                                if (up->port.cons != NULL &&
                                    up->port.line == up->port.cons->index)
                                        saw_console_brk = 1;
                                /*
                                 * We do the SysRQ and SAK checking
                                 * here because otherwise the break
                                 * may get masked by ignore_status_mask
                                 * or read_status_mask.
                                 */
                                if (uart_handle_break(&up->port))
                                        goto ignore_char;
                        } else if (*status & UART_LSR_PE)
                                up->port.icount.parity++;
                        else if (*status & UART_LSR_FE)
                                up->port.icount.frame++;
                        if (*status & UART_LSR_OE)
                                up->port.icount.overrun++;

                        /*
                         * Mask off conditions which should be ingored.
                         */
                        *status &= up->port.read_status_mask;

                        if (up->port.cons != NULL &&
                            up->port.line == up->port.cons->index) {
                                /* Recover the break flag from console xmit */
                                *status |= up->lsr_break_flag;
                                up->lsr_break_flag = 0;
                        }

                        if (*status & UART_LSR_BI) {
                                flag = TTY_BREAK;
                        } else if (*status & UART_LSR_PE)
                                flag = TTY_PARITY;
                        else if (*status & UART_LSR_FE)
                                flag = TTY_FRAME;
                }
                if (uart_handle_sysrq_char(&up->port, ch))
                        goto ignore_char;
                if ((*status & up->port.ignore_status_mask) == 0)
                        tty_insert_flip_char(port, ch, flag);
                if (*status & UART_LSR_OE)
                        /*
                         * Overrun is special, since it's reported
                         * immediately, and doesn't affect the current
                         * character.
                         */
                         tty_insert_flip_char(port, 0, TTY_OVERRUN);
        ignore_char:
                *status = serial_in(up, UART_LSR);
        } while ((*status & UART_LSR_DR) && (max_count-- > 0));

        if (saw_console_brk)
                sun_do_break();
}

static void transmit_chars(struct uart_sunsu_port *up)
{
        struct tty_port *tport = &up->port.state->port;
        unsigned char ch;
        int count;

        if (up->port.x_char) {
                serial_out(up, UART_TX, up->port.x_char);
                up->port.icount.tx++;
                up->port.x_char = 0;
                return;
        }
        if (uart_tx_stopped(&up->port)) {
                sunsu_stop_tx(&up->port);
                return;
        }
        if (kfifo_is_empty(&tport->xmit_fifo)) {
                __stop_tx(up);
                return;
        }

        count = up->port.fifosize;
        do {
                if (!uart_fifo_get(&up->port, &ch))
                        break;

                serial_out(up, UART_TX, ch);
        } while (--count > 0);

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

        if (kfifo_is_empty(&tport->xmit_fifo))
                __stop_tx(up);
}

static void check_modem_status(struct uart_sunsu_port *up)
{
        int status;

        status = serial_in(up, UART_MSR);

        if ((status & UART_MSR_ANY_DELTA) == 0)
                return;

        if (status & UART_MSR_TERI)
                up->port.icount.rng++;
        if (status & UART_MSR_DDSR)
                up->port.icount.dsr++;
        if (status & UART_MSR_DDCD)
                uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
        if (status & UART_MSR_DCTS)
                uart_handle_cts_change(&up->port, status & UART_MSR_CTS);

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

static irqreturn_t sunsu_serial_interrupt(int irq, void *dev_id)
{
        struct uart_sunsu_port *up = dev_id;
        unsigned long flags;
        unsigned char status;

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

        do {
                status = serial_in(up, UART_LSR);
                if (status & UART_LSR_DR)
                        receive_chars(up, &status);
                check_modem_status(up);
                if (status & UART_LSR_THRE)
                        transmit_chars(up);

                tty_flip_buffer_push(&up->port.state->port);

        } while (!(serial_in(up, UART_IIR) & UART_IIR_NO_INT));

        uart_port_unlock_irqrestore(&up->port, flags);

        return IRQ_HANDLED;
}

/* Separate interrupt handling path for keyboard/mouse ports.  */

static void
sunsu_change_speed(struct uart_port *port, unsigned int cflag,
                   unsigned int iflag, unsigned int quot);

static void sunsu_change_mouse_baud(struct uart_sunsu_port *up)
{
        unsigned int cur_cflag = up->cflag;
        int quot, new_baud;

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

        quot = up->port.uartclk / (16 * new_baud);

        sunsu_change_speed(&up->port, up->cflag, 0, quot);
}

static void receive_kbd_ms_chars(struct uart_sunsu_port *up, int is_break)
{
        do {
                unsigned char ch = serial_in(up, UART_RX);

                /* Stop-A is handled by drivers/char/keyboard.c now. */
                if (up->su_type == SU_PORT_KBD) {
#ifdef CONFIG_SERIO
                        serio_interrupt(&up->serio, ch, 0);
#endif
                } else if (up->su_type == SU_PORT_MS) {
                        int ret = suncore_mouse_baud_detection(ch, is_break);

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

                        case 0:
#ifdef CONFIG_SERIO
                                serio_interrupt(&up->serio, ch, 0);
#endif
                                break;
                        }
                }
        } while (serial_in(up, UART_LSR) & UART_LSR_DR);
}

static irqreturn_t sunsu_kbd_ms_interrupt(int irq, void *dev_id)
{
        struct uart_sunsu_port *up = dev_id;

        if (!(serial_in(up, UART_IIR) & UART_IIR_NO_INT)) {
                unsigned char status = serial_in(up, UART_LSR);

                if ((status & UART_LSR_DR) || (status & UART_LSR_BI))
                        receive_kbd_ms_chars(up, (status & UART_LSR_BI) != 0);
        }

        return IRQ_HANDLED;
}

static unsigned int sunsu_tx_empty(struct uart_port *port)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);
        unsigned long flags;
        unsigned int ret;

        uart_port_lock_irqsave(&up->port, &flags);
        ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
        uart_port_unlock_irqrestore(&up->port, flags);

        return ret;
}

static unsigned int sunsu_get_mctrl(struct uart_port *port)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);
        unsigned char status;
        unsigned int ret;

        status = serial_in(up, UART_MSR);

        ret = 0;
        if (status & UART_MSR_DCD)
                ret |= TIOCM_CAR;
        if (status & UART_MSR_RI)
                ret |= TIOCM_RNG;
        if (status & UART_MSR_DSR)
                ret |= TIOCM_DSR;
        if (status & UART_MSR_CTS)
                ret |= TIOCM_CTS;
        return ret;
}

static void sunsu_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);
        unsigned char mcr = 0;

        if (mctrl & TIOCM_RTS)
                mcr |= UART_MCR_RTS;
        if (mctrl & TIOCM_DTR)
                mcr |= UART_MCR_DTR;
        if (mctrl & TIOCM_OUT1)
                mcr |= UART_MCR_OUT1;
        if (mctrl & TIOCM_OUT2)
                mcr |= UART_MCR_OUT2;
        if (mctrl & TIOCM_LOOP)
                mcr |= UART_MCR_LOOP;

        serial_out(up, UART_MCR, mcr);
}

static void sunsu_break_ctl(struct uart_port *port, int break_state)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);
        unsigned long flags;

        uart_port_lock_irqsave(&up->port, &flags);
        if (break_state == -1)
                up->lcr |= UART_LCR_SBC;
        else
                up->lcr &= ~UART_LCR_SBC;
        serial_out(up, UART_LCR, up->lcr);
        uart_port_unlock_irqrestore(&up->port, flags);
}

static int sunsu_startup(struct uart_port *port)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);
        unsigned long flags;
        int retval;

        if (up->port.type == PORT_16C950) {
                /* Wake up and initialize UART */
                up->acr = 0;
                serial_out(up, UART_LCR, 0xBF);
                serial_out(up, UART_EFR, UART_EFR_ECB);
                serial_out(up, UART_IER, 0);
                serial_out(up, UART_LCR, 0);
                serial_icr_write(up, UART_CSR, 0); /* Reset the UART */
                serial_out(up, UART_LCR, 0xBF);
                serial_out(up, UART_EFR, UART_EFR_ECB);
                serial_out(up, UART_LCR, 0);
        }

#ifdef CONFIG_SERIAL_8250_RSA
        /*
         * If this is an RSA port, see if we can kick it up to the
         * higher speed clock.
         */
        enable_rsa(up);
#endif

        /*
         * Clear the FIFO buffers and disable them.
         * (they will be reenabled in set_termios())
         */
        if (uart_config[up->port.type].flags & UART_CLEAR_FIFO) {
                serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
                serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
                                UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
                serial_out(up, UART_FCR, 0);
        }

        /*
         * Clear the interrupt registers.
         */
        (void) serial_in(up, UART_LSR);
        (void) serial_in(up, UART_RX);
        (void) serial_in(up, UART_IIR);
        (void) serial_in(up, UART_MSR);

        /*
         * At this point, there's no way the LSR could still be 0xff;
         * if it is, then bail out, because there's likely no UART
         * here.
         */
        if (!(up->port.flags & UPF_BUGGY_UART) &&
            (serial_in(up, UART_LSR) == 0xff)) {
                printk("ttyS%d: LSR safety check engaged!\n", up->port.line);
                return -ENODEV;
        }

        if (up->su_type != SU_PORT_PORT) {
                retval = request_irq(up->port.irq, sunsu_kbd_ms_interrupt,
                                     IRQF_SHARED, su_typev[up->su_type], up);
        } else {
                retval = request_irq(up->port.irq, sunsu_serial_interrupt,
                                     IRQF_SHARED, su_typev[up->su_type], up);
        }
        if (retval) {
                printk("su: Cannot register IRQ %d\n", up->port.irq);
                return retval;
        }

        /*
         * Now, initialize the UART
         */
        serial_out(up, UART_LCR, UART_LCR_WLEN8);

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

        up->port.mctrl |= TIOCM_OUT2;

        sunsu_set_mctrl(&up->port, up->port.mctrl);
        uart_port_unlock_irqrestore(&up->port, flags);

        /*
         * Finally, enable interrupts.  Note: Modem status interrupts
         * are set via set_termios(), which will be occurring imminently
         * anyway, so we don't enable them here.
         */
        up->ier = UART_IER_RLSI | UART_IER_RDI;
        serial_out(up, UART_IER, up->ier);

        if (up->port.flags & UPF_FOURPORT) {
                unsigned int icp;
                /*
                 * Enable interrupts on the AST Fourport board
                 */
                icp = (up->port.iobase & 0xfe0) | 0x01f;
                outb_p(0x80, icp);
                (void) inb_p(icp);
        }

        /*
         * And clear the interrupt registers again for luck.
         */
        (void) serial_in(up, UART_LSR);
        (void) serial_in(up, UART_RX);
        (void) serial_in(up, UART_IIR);
        (void) serial_in(up, UART_MSR);

        return 0;
}

static void sunsu_shutdown(struct uart_port *port)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);
        unsigned long flags;

        /*
         * Disable interrupts from this port
         */
        up->ier = 0;
        serial_out(up, UART_IER, 0);

        uart_port_lock_irqsave(&up->port, &flags);
        if (up->port.flags & UPF_FOURPORT) {
                /* reset interrupts on the AST Fourport board */
                inb((up->port.iobase & 0xfe0) | 0x1f);
                up->port.mctrl |= TIOCM_OUT1;
        } else
                up->port.mctrl &= ~TIOCM_OUT2;

        sunsu_set_mctrl(&up->port, up->port.mctrl);
        uart_port_unlock_irqrestore(&up->port, flags);

        /*
         * Disable break condition and FIFOs
         */
        serial_out(up, UART_LCR, serial_in(up, UART_LCR) & ~UART_LCR_SBC);
        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
                                  UART_FCR_CLEAR_RCVR |
                                  UART_FCR_CLEAR_XMIT);
        serial_out(up, UART_FCR, 0);

#ifdef CONFIG_SERIAL_8250_RSA
        /*
         * Reset the RSA board back to 115kbps compat mode.
         */
        disable_rsa(up);
#endif

        /*
         * Read data port to reset things.
         */
        (void) serial_in(up, UART_RX);

        free_irq(up->port.irq, up);
}

static void
sunsu_change_speed(struct uart_port *port, unsigned int cflag,
                   unsigned int iflag, unsigned int quot)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);
        unsigned char cval, fcr = 0;
        unsigned long flags;

        switch (cflag & CSIZE) {
        case CS5:
                cval = 0x00;
                break;
        case CS6:
                cval = 0x01;
                break;
        case CS7:
                cval = 0x02;
                break;
        default:
        case CS8:
                cval = 0x03;
                break;
        }

        if (cflag & CSTOPB)
                cval |= 0x04;
        if (cflag & PARENB)
                cval |= UART_LCR_PARITY;
        if (!(cflag & PARODD))
                cval |= UART_LCR_EPAR;
        if (cflag & CMSPAR)
                cval |= UART_LCR_SPAR;

        /*
         * Work around a bug in the Oxford Semiconductor 952 rev B
         * chip which causes it to seriously miscalculate baud rates
         * when DLL is 0.
         */
        if ((quot & 0xff) == 0 && up->port.type == PORT_16C950 &&
            up->rev == 0x5201)
                quot ++;

        if (uart_config[up->port.type].flags & UART_USE_FIFO) {
                if ((up->port.uartclk / quot) < (2400 * 16))
                        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
#ifdef CONFIG_SERIAL_8250_RSA
                else if (up->port.type == PORT_RSA)
                        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_14;
#endif
                else
                        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_8;
        }
        if (up->port.type == PORT_16750)
                fcr |= UART_FCR7_64BYTE;

        /*
         * Ok, we're now changing the port state.  Do it with
         * interrupts disabled.
         */
        uart_port_lock_irqsave(&up->port, &flags);

        /*
         * Update the per-port timeout.
         */
        uart_update_timeout(port, cflag, (port->uartclk / (16 * quot)));

        up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
        if (iflag & INPCK)
                up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
        if (iflag & (IGNBRK | BRKINT | PARMRK))
                up->port.read_status_mask |= UART_LSR_BI;

        /*
         * Characteres to ignore
         */
        up->port.ignore_status_mask = 0;
        if (iflag & IGNPAR)
                up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
        if (iflag & IGNBRK) {
                up->port.ignore_status_mask |= UART_LSR_BI;
                /*
                 * If we're ignoring parity and break indicators,
                 * ignore overruns too (for real raw support).
                 */
                if (iflag & IGNPAR)
                        up->port.ignore_status_mask |= UART_LSR_OE;
        }

        /*
         * ignore all characters if CREAD is not set
         */
        if ((cflag & CREAD) == 0)
                up->port.ignore_status_mask |= UART_LSR_DR;

        /*
         * CTS flow control flag and modem status interrupts
         */
        up->ier &= ~UART_IER_MSI;
        if (UART_ENABLE_MS(&up->port, cflag))
                up->ier |= UART_IER_MSI;

        serial_out(up, UART_IER, up->ier);

        if (uart_config[up->port.type].flags & UART_STARTECH) {
                serial_out(up, UART_LCR, 0xBF);
                serial_out(up, UART_EFR, cflag & CRTSCTS ? UART_EFR_CTS :0);
        }
        serial_out(up, UART_LCR, cval | UART_LCR_DLAB);/* set DLAB */
        serial_out(up, UART_DLL, quot & 0xff);          /* LS of divisor */
        serial_out(up, UART_DLM, quot >> 8);            /* MS of divisor */
        if (up->port.type == PORT_16750)
                serial_out(up, UART_FCR, fcr);          /* set fcr */
        serial_out(up, UART_LCR, cval);         /* reset DLAB */
        up->lcr = cval;                                 /* Save LCR */
        if (up->port.type != PORT_16750) {
                if (fcr & UART_FCR_ENABLE_FIFO) {
                        /* emulated UARTs (Lucent Venus 167x) need two steps */
                        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
                }
                serial_out(up, UART_FCR, fcr);          /* set fcr */
        }

        up->cflag = cflag;

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

static void
sunsu_set_termios(struct uart_port *port, struct ktermios *termios,
                  const struct ktermios *old)
{
        unsigned int baud, quot;

        /*
         * Ask the core to calculate the divisor for us.
         */
        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16); 
        quot = uart_get_divisor(port, baud);

        sunsu_change_speed(port, termios->c_cflag, termios->c_iflag, quot);
}

static void sunsu_release_port(struct uart_port *port)
{
}

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

static void sunsu_config_port(struct uart_port *port, int flags)
{
        struct uart_sunsu_port *up =
                container_of(port, struct uart_sunsu_port, port);

        if (flags & UART_CONFIG_TYPE) {
                /*
                 * We are supposed to call autoconfig here, but this requires
                 * splitting all the OBP probing crap from the UART probing.
                 * We'll do it when we kill sunsu.c altogether.
                 */
                port->type = up->type_probed;   /* XXX */
        }
}

static int
sunsu_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        return -EINVAL;
}

static const char *
sunsu_type(struct uart_port *port)
{
        int type = port->type;

        if (type >= ARRAY_SIZE(uart_config))
                type = 0;
        return uart_config[type].name;
}

static const struct uart_ops sunsu_pops = {
        .tx_empty       = sunsu_tx_empty,
        .set_mctrl      = sunsu_set_mctrl,
        .get_mctrl      = sunsu_get_mctrl,
        .stop_tx        = sunsu_stop_tx,
        .start_tx       = sunsu_start_tx,
        .stop_rx        = sunsu_stop_rx,
        .enable_ms      = sunsu_enable_ms,
        .break_ctl      = sunsu_break_ctl,
        .startup        = sunsu_startup,
        .shutdown       = sunsu_shutdown,
        .set_termios    = sunsu_set_termios,
        .type           = sunsu_type,
        .release_port   = sunsu_release_port,
        .request_port   = sunsu_request_port,
        .config_port    = sunsu_config_port,
        .verify_port    = sunsu_verify_port,
};

#define UART_NR 4

static struct uart_sunsu_port sunsu_ports[UART_NR];
static int nr_inst; /* Number of already registered ports */

#ifdef CONFIG_SERIO

static DEFINE_SPINLOCK(sunsu_serio_lock);

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

        spin_lock_irqsave(&sunsu_serio_lock, flags);

        do {
                lsr = serial_in(up, UART_LSR);
        } while (!(lsr & UART_LSR_THRE));

        /* Send the character out. */
        serial_out(up, UART_TX, ch);

        spin_unlock_irqrestore(&sunsu_serio_lock, flags);

        return 0;
}

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

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

        return ret;
}

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

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

#endif /* CONFIG_SERIO */

static void sunsu_autoconfig(struct uart_sunsu_port *up)
{
        unsigned char status1, status2, scratch, scratch2, scratch3;
        unsigned char save_lcr, save_mcr;
        unsigned long flags;

        if (up->su_type == SU_PORT_NONE)
                return;

        up->type_probed = PORT_UNKNOWN;
        up->port.iotype = UPIO_MEM;

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

        if (!(up->port.flags & UPF_BUGGY_UART)) {
                /*
                 * Do a simple existence test first; if we fail this, there's
                 * no point trying anything else.
                 *
                 * 0x80 is used as a nonsense port to prevent against false
                 * positives due to ISA bus float.  The assumption is that
                 * 0x80 is a non-existent port; which should be safe since
                 * include/asm/io.h also makes this assumption.
                 */
                scratch = serial_in(up, UART_IER);
                serial_out(up, UART_IER, 0);
#ifdef __i386__
                outb(0xff, 0x080);
#endif
                scratch2 = serial_in(up, UART_IER);
                serial_out(up, UART_IER, 0x0f);
#ifdef __i386__
                outb(0, 0x080);
#endif
                scratch3 = serial_in(up, UART_IER);
                serial_out(up, UART_IER, scratch);
                if (scratch2 != 0 || scratch3 != 0x0F)
                        goto out;       /* We failed; there's nothing here */
        }

        save_mcr = serial_in(up, UART_MCR);
        save_lcr = serial_in(up, UART_LCR);

        /* 
         * Check to see if a UART is really there.  Certain broken
         * internal modems based on the Rockwell chipset fail this
         * test, because they apparently don't implement the loopback
         * test mode.  So this test is skipped on the COM 1 through
         * COM 4 ports.  This *should* be safe, since no board
         * manufacturer would be stupid enough to design a board
         * that conflicts with COM 1-4 --- we hope!
         */
        if (!(up->port.flags & UPF_SKIP_TEST)) {
                serial_out(up, UART_MCR, UART_MCR_LOOP | 0x0A);
                status1 = serial_in(up, UART_MSR) & 0xF0;
                serial_out(up, UART_MCR, save_mcr);
                if (status1 != 0x90)
                        goto out;       /* We failed loopback test */
        }
        serial_out(up, UART_LCR, 0xBF); /* set up for StarTech test */
        serial_out(up, UART_EFR, 0);            /* EFR is the same as FCR */
        serial_out(up, UART_LCR, 0);
        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
        scratch = serial_in(up, UART_IIR) >> 6;
        switch (scratch) {
                case 0:
                        up->port.type = PORT_16450;
                        break;
                case 1:
                        up->port.type = PORT_UNKNOWN;
                        break;
                case 2:
                        up->port.type = PORT_16550;
                        break;
                case 3:
                        up->port.type = PORT_16550A;
                        break;
        }
        if (up->port.type == PORT_16550A) {
                /* Check for Startech UART's */
                serial_out(up, UART_LCR, UART_LCR_DLAB);
                if (serial_in(up, UART_EFR) == 0) {
                        up->port.type = PORT_16650;
                } else {
                        serial_out(up, UART_LCR, 0xBF);
                        if (serial_in(up, UART_EFR) == 0)
                                up->port.type = PORT_16650V2;
                }
        }
        if (up->port.type == PORT_16550A) {
                /* Check for TI 16750 */
                serial_out(up, UART_LCR, save_lcr | UART_LCR_DLAB);
                serial_out(up, UART_FCR,
                            UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
                scratch = serial_in(up, UART_IIR) >> 5;
                if (scratch == 7) {
                        /*
                         * If this is a 16750, and not a cheap UART
                         * clone, then it should only go into 64 byte
                         * mode if the UART_FCR7_64BYTE bit was set
                         * while UART_LCR_DLAB was latched.
                         */
                        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
                        serial_out(up, UART_LCR, 0);
                        serial_out(up, UART_FCR,
                                    UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
                        scratch = serial_in(up, UART_IIR) >> 5;
                        if (scratch == 6)
                                up->port.type = PORT_16750;
                }
                serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
        }
        serial_out(up, UART_LCR, save_lcr);
        if (up->port.type == PORT_16450) {
                scratch = serial_in(up, UART_SCR);
                serial_out(up, UART_SCR, 0xa5);
                status1 = serial_in(up, UART_SCR);
                serial_out(up, UART_SCR, 0x5a);
                status2 = serial_in(up, UART_SCR);
                serial_out(up, UART_SCR, scratch);

                if ((status1 != 0xa5) || (status2 != 0x5a))
                        up->port.type = PORT_8250;
        }

        up->port.fifosize = uart_config[up->port.type].dfl_xmit_fifo_size;

        if (up->port.type == PORT_UNKNOWN)
                goto out;
        up->type_probed = up->port.type;        /* XXX */

        /*
         * Reset the UART.
         */
#ifdef CONFIG_SERIAL_8250_RSA
        if (up->port.type == PORT_RSA)
                serial_out(up, UART_RSA_FRR, 0);
#endif
        serial_out(up, UART_MCR, save_mcr);
        serial_out(up, UART_FCR, (UART_FCR_ENABLE_FIFO |
                                     UART_FCR_CLEAR_RCVR |
                                     UART_FCR_CLEAR_XMIT));
        serial_out(up, UART_FCR, 0);
        (void)serial_in(up, UART_RX);
        serial_out(up, UART_IER, 0);

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

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

static int sunsu_kbd_ms_init(struct uart_sunsu_port *up)
{
        int quot, baud;
#ifdef CONFIG_SERIO
        struct serio *serio;
#endif

        if (up->su_type == SU_PORT_KBD) {
                up->cflag = B1200 | CS8 | CLOCAL | CREAD;
                baud = 1200;
        } else {
                up->cflag = B4800 | CS8 | CLOCAL | CREAD;
                baud = 4800;
        }
        quot = up->port.uartclk / (16 * baud);

        sunsu_autoconfig(up);
        if (up->port.type == PORT_UNKNOWN)
                return -ENODEV;

        printk("%pOF: %s port at %llx, irq %u\n",
               up->port.dev->of_node,
               (up->su_type == SU_PORT_KBD) ? "Keyboard" : "Mouse",
               (unsigned long long) up->port.mapbase,
               up->port.irq);

#ifdef CONFIG_SERIO
        serio = &up->serio;
        serio->port_data = up;

        serio->id.type = SERIO_RS232;
        if (up->su_type == SU_PORT_KBD) {
                serio->id.proto = SERIO_SUNKBD;
                strscpy(serio->name, "sukbd", sizeof(serio->name));
        } else {
                serio->id.proto = SERIO_SUN;
                serio->id.extra = 1;
                strscpy(serio->name, "sums", sizeof(serio->name));
        }
        strscpy(serio->phys,
                (!(up->port.line & 1) ? "su/serio0" : "su/serio1"),
                sizeof(serio->phys));

        serio->write = sunsu_serio_write;
        serio->open = sunsu_serio_open;
        serio->close = sunsu_serio_close;
        serio->dev.parent = up->port.dev;

        serio_register_port(serio);
#endif

        sunsu_change_speed(&up->port, up->cflag, 0, quot);

        sunsu_startup(&up->port);
        return 0;
}

/*
 * ------------------------------------------------------------
 * Serial console driver
 * ------------------------------------------------------------
 */

#ifdef CONFIG_SERIAL_SUNSU_CONSOLE

/*
 *      Wait for transmitter & holding register to empty
 */
static void wait_for_xmitr(struct uart_sunsu_port *up)
{
        unsigned int status, tmout = 10000;

        /* Wait up to 10ms for the character(s) to be sent. */
        do {
                status = serial_in(up, UART_LSR);

                if (status & UART_LSR_BI)
                        up->lsr_break_flag = UART_LSR_BI;

                if (--tmout == 0)
                        break;
                udelay(1);
        } while (!uart_lsr_tx_empty(status));

        /* Wait up to 1s for flow control if necessary */
        if (up->port.flags & UPF_CONS_FLOW) {
                tmout = 1000000;
                while (--tmout &&
                       ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0))
                        udelay(1);
        }
}

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

        wait_for_xmitr(up);
        serial_out(up, UART_TX, ch);
}

/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 */
static void sunsu_console_write(struct console *co, const char *s,
                                unsigned int count)
{
        struct uart_sunsu_port *up = &sunsu_ports[co->index];
        unsigned long flags;
        unsigned int ier;
        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);

        /*
         *      First save the UER then disable the interrupts
         */
        ier = serial_in(up, UART_IER);
        serial_out(up, UART_IER, 0);

        uart_console_write(&up->port, s, count, sunsu_console_putchar);

        /*
         *      Finally, wait for transmitter to become empty
         *      and restore the IER
         */
        wait_for_xmitr(up);
        serial_out(up, UART_IER, ier);

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

/*
 *      Setup initial baud/bits/parity. We do two things here:
 *      - construct a cflag setting for the first su_open()
 *      - initialize the serial port
 *      Return non-zero if we didn't find a serial port.
 */
static int __init sunsu_console_setup(struct console *co, char *options)
{
        static struct ktermios dummy;
        struct ktermios termios;
        struct uart_port *port;

        printk("Console: ttyS%d (SU)\n",
               (sunsu_reg.minor - 64) + co->index);

        if (co->index > nr_inst)
                return -ENODEV;
        port = &sunsu_ports[co->index].port;

        /*
         * Temporary fix.
         */
        spin_lock_init(&port->lock);

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

        memset(&termios, 0, sizeof(struct ktermios));
        termios.c_cflag = co->cflag;
        port->mctrl |= TIOCM_DTR;
        port->ops->set_termios(port, &termios, &dummy);

        return 0;
}

static struct console sunsu_console = {
        .name   =       "ttyS",
        .write  =       sunsu_console_write,
        .device =       uart_console_device,
        .setup  =       sunsu_console_setup,
        .flags  =       CON_PRINTBUFFER,
        .index  =       -1,
        .data   =       &sunsu_reg,
};

/*
 *      Register console.
 */

static inline struct console *SUNSU_CONSOLE(void)
{
        return &sunsu_console;
}
#else
#define SUNSU_CONSOLE()                 (NULL)
#define sunsu_serial_console_init()     do { } while (0)
#endif

static enum su_type su_get_type(struct device_node *dp)
{
        struct device_node *ap __free(device_node) =
                            of_find_node_by_path("/aliases");

        if (ap) {
                const char *keyb = of_get_property(ap, "keyboard", NULL);
                const char *ms = of_get_property(ap, "mouse", NULL);

                if (keyb) {
                        struct device_node *match __free(device_node) =
                                            of_find_node_by_path(keyb);

                        if (dp == match)
                                return SU_PORT_KBD;
                }
                if (ms) {
                        struct device_node *match __free(device_node) =
                                            of_find_node_by_path(ms);

                        if (dp == match)
                                return SU_PORT_MS;
                }
        }
        return SU_PORT_PORT;
}

static int su_probe(struct platform_device *op)
{
        struct device_node *dp = op->dev.of_node;
        struct uart_sunsu_port *up;
        struct resource *rp;
        enum su_type type;
        bool ignore_line;
        int err;

        type = su_get_type(dp);
        if (type == SU_PORT_PORT) {
                if (nr_inst >= UART_NR)
                        return -EINVAL;
                up = &sunsu_ports[nr_inst];
        } else {
                up = kzalloc_obj(*up);
                if (!up)
                        return -ENOMEM;
        }

        up->port.line = nr_inst;

        spin_lock_init(&up->port.lock);

        up->su_type = type;

        rp = &op->resource[0];
        up->port.mapbase = rp->start;
        up->reg_size = resource_size(rp);
        up->port.membase = of_ioremap(rp, 0, up->reg_size, "su");
        if (!up->port.membase) {
                if (type != SU_PORT_PORT)
                        kfree(up);
                return -ENOMEM;
        }

        up->port.irq = op->archdata.irqs[0];

        up->port.dev = &op->dev;

        up->port.type = PORT_UNKNOWN;
        up->port.uartclk = (SU_BASE_BAUD * 16);
        up->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_SUNSU_CONSOLE);

        err = 0;
        if (up->su_type == SU_PORT_KBD || up->su_type == SU_PORT_MS) {
                err = sunsu_kbd_ms_init(up);
                if (err) {
                        of_iounmap(&op->resource[0],
                                   up->port.membase, up->reg_size);
                        kfree(up);
                        return err;
                }
                platform_set_drvdata(op, up);

                nr_inst++;

                return 0;
        }

        up->port.flags |= UPF_BOOT_AUTOCONF;

        sunsu_autoconfig(up);

        err = -ENODEV;
        if (up->port.type == PORT_UNKNOWN)
                goto out_unmap;

        up->port.ops = &sunsu_pops;

        ignore_line = false;
        if (of_node_name_eq(dp, "rsc-console") ||
            of_node_name_eq(dp, "lom-console"))
                ignore_line = true;

        sunserial_console_match(SUNSU_CONSOLE(), dp,
                                &sunsu_reg, up->port.line,
                                ignore_line);
        err = uart_add_one_port(&sunsu_reg, &up->port);
        if (err)
                goto out_unmap;

        platform_set_drvdata(op, up);

        nr_inst++;

        return 0;

out_unmap:
        of_iounmap(&op->resource[0], up->port.membase, up->reg_size);
        kfree(up);
        return err;
}

static void su_remove(struct platform_device *op)
{
        struct uart_sunsu_port *up = platform_get_drvdata(op);
        bool kbdms = false;

        if (up->su_type == SU_PORT_MS ||
            up->su_type == SU_PORT_KBD)
                kbdms = true;

        if (kbdms) {
#ifdef CONFIG_SERIO
                serio_unregister_port(&up->serio);
#endif
        } else if (up->port.type != PORT_UNKNOWN)
                uart_remove_one_port(&sunsu_reg, &up->port);

        if (up->port.membase)
                of_iounmap(&op->resource[0], up->port.membase, up->reg_size);

        if (kbdms)
                kfree(up);
}

static const struct of_device_id su_match[] = {
        {
                .name = "su",
        },
        {
                .name = "su_pnp",
        },
        {
                .name = "serial",
                .compatible = "su",
        },
        {
                .type = "serial",
                .compatible = "su",
        },
        {},
};
MODULE_DEVICE_TABLE(of, su_match);

static struct platform_driver su_driver = {
        .driver = {
                .name = "su",
                .of_match_table = su_match,
        },
        .probe          = su_probe,
        .remove         = su_remove,
};

static int __init sunsu_init(void)
{
        struct device_node *dp;
        int err;
        int num_uart = 0;

        for_each_node_by_name(dp, "su") {
                if (su_get_type(dp) == SU_PORT_PORT)
                        num_uart++;
        }
        for_each_node_by_name(dp, "su_pnp") {
                if (su_get_type(dp) == SU_PORT_PORT)
                        num_uart++;
        }
        for_each_node_by_name(dp, "serial") {
                if (of_device_is_compatible(dp, "su")) {
                        if (su_get_type(dp) == SU_PORT_PORT)
                                num_uart++;
                }
        }
        for_each_node_by_type(dp, "serial") {
                if (of_device_is_compatible(dp, "su")) {
                        if (su_get_type(dp) == SU_PORT_PORT)
                                num_uart++;
                }
        }

        if (num_uart) {
                err = sunserial_register_minors(&sunsu_reg, num_uart);
                if (err)
                        return err;
        }

        err = platform_driver_register(&su_driver);
        if (err && num_uart)
                sunserial_unregister_minors(&sunsu_reg, num_uart);

        return err;
}

static void __exit sunsu_exit(void)
{
        platform_driver_unregister(&su_driver);
        if (sunsu_reg.nr)
                sunserial_unregister_minors(&sunsu_reg, sunsu_reg.nr);
}

module_init(sunsu_init);
module_exit(sunsu_exit);

MODULE_AUTHOR("Eddie C. Dost, Peter Zaitcev, and David S. Miller");
MODULE_DESCRIPTION("Sun SU serial port driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");