// SPDX-License-Identifier: GPL-2.0+
/*
 *  m32r_sio.c
 *
 *  Driver for M32R serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *  Based on drivers/serial/8250.c.
 *
 *  Copyright (C) 2001  Russell King.
 *  Copyright (C) 2004  Hirokazu Takata <takata at linux-m32r.org>
 */

/*
 * A note about mapbase / membase
 *
 *  mapbase is the physical address of the IO port.  Currently, we don't
 *  support this very well, and it may well be dropped from this driver
 *  in future.  As such, mapbase should be NULL.
 *
 *  membase is an 'ioremapped' cookie.  This is compatible with the old
 *  serial.c driver, and is currently the preferred form.
 */

#if defined(CONFIG_SERIAL_M32R_SIO_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/serial.h>
#include <linux/delay.h>

#include <asm/m32r.h>
#include <asm/io.h>
#include <asm/irq.h>

#define BAUD_RATE       115200

#include <linux/serial_core.h>
#include "m32r_sio_reg.h"

#define PASS_LIMIT      256

static const struct {
        unsigned int port;
        unsigned int irq;
} old_serial_port[] = {
#if defined(CONFIG_PLAT_USRV)
        /* PORT  IRQ            FLAGS */
        { 0x3F8, PLD_IRQ_UART0 }, /* ttyS0 */
        { 0x2F8, PLD_IRQ_UART1 }, /* ttyS1 */
#elif defined(CONFIG_SERIAL_M32R_PLDSIO)
        { ((unsigned long)PLD_ESIO0CR), PLD_IRQ_SIO0_RCV }, /* ttyS0 */
#else
        { M32R_SIO_OFFSET, M32R_IRQ_SIO0_R }, /* ttyS0 */
#endif
};

#define UART_NR ARRAY_SIZE(old_serial_port)

struct uart_sio_port {
        struct uart_port        port;
        struct timer_list       timer;          /* "no irq" timer */
        struct list_head        list;           /* ports on this IRQ */
        unsigned char           ier;
};

struct irq_info {
        spinlock_t              lock;
        struct list_head        *head;
};

static struct irq_info irq_lists[NR_IRQS];

#ifdef CONFIG_SERIAL_M32R_PLDSIO

#define __sio_in(x) inw((unsigned long)(x))
#define __sio_out(v,x) outw((v),(unsigned long)(x))

static inline void sio_set_baud_rate(unsigned long baud)
{
        unsigned short sbaud;
        sbaud = (boot_cpu_data.bus_clock / (baud * 4))-1;
        __sio_out(sbaud, PLD_ESIO0BAUR);
}

static void sio_reset(void)
{
        unsigned short tmp;

        tmp = __sio_in(PLD_ESIO0RXB);
        tmp = __sio_in(PLD_ESIO0RXB);
        tmp = __sio_in(PLD_ESIO0CR);
        sio_set_baud_rate(BAUD_RATE);
        __sio_out(0x0300, PLD_ESIO0CR);
        __sio_out(0x0003, PLD_ESIO0CR);
}

static void sio_init(void)
{
        unsigned short tmp;

        tmp = __sio_in(PLD_ESIO0RXB);
        tmp = __sio_in(PLD_ESIO0RXB);
        tmp = __sio_in(PLD_ESIO0CR);
        __sio_out(0x0300, PLD_ESIO0CR);
        __sio_out(0x0003, PLD_ESIO0CR);
}

static void sio_error(int *status)
{
        printk("SIO0 error[%04x]\n", *status);
        do {
                sio_init();
        } while ((*status = __sio_in(PLD_ESIO0CR)) != 3);
}

#else /* not CONFIG_SERIAL_M32R_PLDSIO */

#define __sio_in(x) inl(x)
#define __sio_out(v,x) outl((v),(x))

static inline void sio_set_baud_rate(unsigned long baud)
{
        unsigned long i, j;

        i = boot_cpu_data.bus_clock / (baud * 16);
        j = (boot_cpu_data.bus_clock - (i * baud * 16)) / baud;
        i -= 1;
        j = (j + 1) >> 1;

        __sio_out(i, M32R_SIO0_BAUR_PORTL);
        __sio_out(j, M32R_SIO0_RBAUR_PORTL);
}

static void sio_reset(void)
{
        __sio_out(0x00000300, M32R_SIO0_CR_PORTL);      /* init status */
        __sio_out(0x00000800, M32R_SIO0_MOD1_PORTL);    /* 8bit        */
        __sio_out(0x00000080, M32R_SIO0_MOD0_PORTL);    /* 1stop non   */
        sio_set_baud_rate(BAUD_RATE);
        __sio_out(0x00000000, M32R_SIO0_TRCR_PORTL);
        __sio_out(0x00000003, M32R_SIO0_CR_PORTL);      /* RXCEN */
}

static void sio_init(void)
{
        unsigned int tmp;

        tmp = __sio_in(M32R_SIO0_RXB_PORTL);
        tmp = __sio_in(M32R_SIO0_RXB_PORTL);
        tmp = __sio_in(M32R_SIO0_STS_PORTL);
        __sio_out(0x00000003, M32R_SIO0_CR_PORTL);
}

static void sio_error(int *status)
{
        printk("SIO0 error[%04x]\n", *status);
        do {
                sio_init();
        } while ((*status = __sio_in(M32R_SIO0_CR_PORTL)) != 3);
}

#endif /* CONFIG_SERIAL_M32R_PLDSIO */

static unsigned int sio_in(struct uart_sio_port *up, int offset)
{
        return __sio_in(up->port.iobase + offset);
}

static void sio_out(struct uart_sio_port *up, int offset, int value)
{
        __sio_out(value, up->port.iobase + offset);
}

static unsigned int serial_in(struct uart_sio_port *up, int offset)
{
        if (!offset)
                return 0;

        return __sio_in(offset);
}

static void serial_out(struct uart_sio_port *up, int offset, int value)
{
        if (!offset)
                return;

        __sio_out(value, offset);
}

static void m32r_sio_stop_tx(struct uart_port *port)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);

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

static void m32r_sio_start_tx(struct uart_port *port)
{
#ifdef CONFIG_SERIAL_M32R_PLDSIO
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);
        struct circ_buf *xmit = &up->port.state->xmit;

        if (!(up->ier & UART_IER_THRI)) {
                up->ier |= UART_IER_THRI;
                serial_out(up, UART_IER, up->ier);
                if (!uart_circ_empty(xmit)) {
                        serial_out(up, UART_TX, xmit->buf[xmit->tail]);
                        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                        up->port.icount.tx++;
                }
        }
        while((serial_in(up, UART_LSR) & UART_EMPTY) != UART_EMPTY);
#else
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);

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

static void m32r_sio_stop_rx(struct uart_port *port)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);

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

static void m32r_sio_enable_ms(struct uart_port *port)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);

        up->ier |= UART_IER_MSI;
        serial_out(up, UART_IER, up->ier);
}

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

        do {
                ch = sio_in(up, SIORXB);
                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++;
                                /*
                                 * 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 (*status & UART_LSR_BI) {
                                pr_debug("handling break....\n");
                                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));

        spin_unlock(&up->port.lock);
        tty_flip_buffer_push(port);
        spin_lock(&up->port.lock);
}

static void transmit_chars(struct uart_sio_port *up)
{
        struct circ_buf *xmit = &up->port.state->xmit;
        int count;

        if (up->port.x_char) {
#ifndef CONFIG_SERIAL_M32R_PLDSIO       /* XXX */
                serial_out(up, UART_TX, up->port.x_char);
#endif
                up->port.icount.tx++;
                up->port.x_char = 0;
                return;
        }
        if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
                m32r_sio_stop_tx(&up->port);
                return;
        }

        count = up->port.fifosize;
        do {
                serial_out(up, UART_TX, xmit->buf[xmit->tail]);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                up->port.icount.tx++;
                if (uart_circ_empty(xmit))
                        break;
                while (!(serial_in(up, UART_LSR) & UART_LSR_THRE));

        } while (--count > 0);

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(&up->port);

        pr_debug("THRE...\n");

        if (uart_circ_empty(xmit))
                m32r_sio_stop_tx(&up->port);
}

/*
 * This handles the interrupt from one port.
 */
static inline void m32r_sio_handle_port(struct uart_sio_port *up,
        unsigned int status)
{
        pr_debug("status = %x...\n", status);

        if (status & 0x04)
                receive_chars(up, &status);
        if (status & 0x01)
                transmit_chars(up);
}

/*
 * This is the serial driver's interrupt routine.
 *
 * Arjan thinks the old way was overly complex, so it got simplified.
 * Alan disagrees, saying that need the complexity to handle the weird
 * nature of ISA shared interrupts.  (This is a special exception.)
 *
 * In order to handle ISA shared interrupts properly, we need to check
 * that all ports have been serviced, and therefore the ISA interrupt
 * line has been de-asserted.
 *
 * This means we need to loop through all ports. checking that they
 * don't have an interrupt pending.
 */
static irqreturn_t m32r_sio_interrupt(int irq, void *dev_id)
{
        struct irq_info *i = dev_id;
        struct list_head *l, *end = NULL;
        int pass_counter = 0;

        pr_debug("m32r_sio_interrupt(%d)...\n", irq);

#ifdef CONFIG_SERIAL_M32R_PLDSIO
//      if (irq == PLD_IRQ_SIO0_SND)
//              irq = PLD_IRQ_SIO0_RCV;
#else
        if (irq == M32R_IRQ_SIO0_S)
                irq = M32R_IRQ_SIO0_R;
#endif

        spin_lock(&i->lock);

        l = i->head;
        do {
                struct uart_sio_port *up;
                unsigned int sts;

                up = list_entry(l, struct uart_sio_port, list);

                sts = sio_in(up, SIOSTS);
                if (sts & 0x5) {
                        spin_lock(&up->port.lock);
                        m32r_sio_handle_port(up, sts);
                        spin_unlock(&up->port.lock);

                        end = NULL;
                } else if (end == NULL)
                        end = l;

                l = l->next;

                if (l == i->head && pass_counter++ > PASS_LIMIT) {
                        if (sts & 0xe0)
                                sio_error(&sts);
                        break;
                }
        } while (l != end);

        spin_unlock(&i->lock);

        pr_debug("end.\n");

        return IRQ_HANDLED;
}

/*
 * To support ISA shared interrupts, we need to have one interrupt
 * handler that ensures that the IRQ line has been deasserted
 * before returning.  Failing to do this will result in the IRQ
 * line being stuck active, and, since ISA irqs are edge triggered,
 * no more IRQs will be seen.
 */
static void serial_do_unlink(struct irq_info *i, struct uart_sio_port *up)
{
        spin_lock_irq(&i->lock);

        if (!list_empty(i->head)) {
                if (i->head == &up->list)
                        i->head = i->head->next;
                list_del(&up->list);
        } else {
                BUG_ON(i->head != &up->list);
                i->head = NULL;
        }

        spin_unlock_irq(&i->lock);
}

static int serial_link_irq_chain(struct uart_sio_port *up)
{
        struct irq_info *i = irq_lists + up->port.irq;
        int ret, irq_flags = 0;

        spin_lock_irq(&i->lock);

        if (i->head) {
                list_add(&up->list, i->head);
                spin_unlock_irq(&i->lock);

                ret = 0;
        } else {
                INIT_LIST_HEAD(&up->list);
                i->head = &up->list;
                spin_unlock_irq(&i->lock);

                ret = request_irq(up->port.irq, m32r_sio_interrupt,
                                  irq_flags, "SIO0-RX", i);
                ret |= request_irq(up->port.irq + 1, m32r_sio_interrupt,
                                  irq_flags, "SIO0-TX", i);
                if (ret < 0)
                        serial_do_unlink(i, up);
        }

        return ret;
}

static void serial_unlink_irq_chain(struct uart_sio_port *up)
{
        struct irq_info *i = irq_lists + up->port.irq;

        BUG_ON(i->head == NULL);

        if (list_empty(i->head)) {
                free_irq(up->port.irq, i);
                free_irq(up->port.irq + 1, i);
        }

        serial_do_unlink(i, up);
}

/*
 * This function is used to handle ports that do not have an interrupt.
 */
static void m32r_sio_timeout(struct timer_list *t)
{
        struct uart_sio_port *up = from_timer(up, t, timer);
        unsigned int timeout;
        unsigned int sts;

        sts = sio_in(up, SIOSTS);
        if (sts & 0x5) {
                spin_lock(&up->port.lock);
                m32r_sio_handle_port(up, sts);
                spin_unlock(&up->port.lock);
        }

        timeout = up->port.timeout;
        timeout = timeout > 6 ? (timeout / 2 - 2) : 1;
        mod_timer(&up->timer, jiffies + timeout);
}

static unsigned int m32r_sio_tx_empty(struct uart_port *port)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);
        unsigned long flags;
        unsigned int ret;

        spin_lock_irqsave(&up->port.lock, flags);
        ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
        spin_unlock_irqrestore(&up->port.lock, flags);

        return ret;
}

static unsigned int m32r_sio_get_mctrl(struct uart_port *port)
{
        return 0;
}

static void m32r_sio_set_mctrl(struct uart_port *port, unsigned int mctrl)
{

}

static void m32r_sio_break_ctl(struct uart_port *port, int break_state)
{

}

static int m32r_sio_startup(struct uart_port *port)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);
        int retval;

        sio_init();

        /*
         * If the "interrupt" for this port doesn't correspond with any
         * hardware interrupt, we use a timer-based system.  The original
         * driver used to do this with IRQ0.
         */
        if (!up->port.irq) {
                unsigned int timeout = up->port.timeout;

                timeout = timeout > 6 ? (timeout / 2 - 2) : 1;

                mod_timer(&up->timer, jiffies + timeout);
        } else {
                retval = serial_link_irq_chain(up);
                if (retval)
                        return retval;
        }

        /*
         * 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.
         * - M32R_SIO: 0x0c
         * - M32R_PLDSIO: 0x04
         */
        up->ier = UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI;
        sio_out(up, SIOTRCR, up->ier);

        /*
         * And clear the interrupt registers again for luck.
         */
        sio_reset();

        return 0;
}

static void m32r_sio_shutdown(struct uart_port *port)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);

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

        /*
         * Disable break condition and FIFOs
         */

        sio_init();

        if (!up->port.irq)
                del_timer_sync(&up->timer);
        else
                serial_unlink_irq_chain(up);
}

static unsigned int m32r_sio_get_divisor(struct uart_port *port,
        unsigned int baud)
{
        return uart_get_divisor(port, baud);
}

static void m32r_sio_set_termios(struct uart_port *port,
        struct ktermios *termios, struct ktermios *old)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);
        unsigned char cval = 0;
        unsigned long flags;
        unsigned int baud, quot;

        switch (termios->c_cflag & CSIZE) {
        case CS5:
                cval = UART_LCR_WLEN5;
                break;
        case CS6:
                cval = UART_LCR_WLEN6;
                break;
        case CS7:
                cval = UART_LCR_WLEN7;
                break;
        default:
        case CS8:
                cval = UART_LCR_WLEN8;
                break;
        }

        if (termios->c_cflag & CSTOPB)
                cval |= UART_LCR_STOP;
        if (termios->c_cflag & PARENB)
                cval |= UART_LCR_PARITY;
        if (!(termios->c_cflag & PARODD))
                cval |= UART_LCR_EPAR;
#ifdef CMSPAR
        if (termios->c_cflag & CMSPAR)
                cval |= UART_LCR_SPAR;
#endif

        /*
         * Ask the core to calculate the divisor for us.
         */
#ifdef CONFIG_SERIAL_M32R_PLDSIO
        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/4);
#else
        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
#endif
        quot = m32r_sio_get_divisor(port, baud);

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

        sio_set_baud_rate(baud);

        /*
         * Update the per-port timeout.
         */
        uart_update_timeout(port, termios->c_cflag, baud);

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

        /*
         * Characteres to ignore
         */
        up->port.ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
        if (termios->c_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 (termios->c_iflag & IGNPAR)
                        up->port.ignore_status_mask |= UART_LSR_OE;
        }

        /*
         * ignore all characters if CREAD is not set
         */
        if ((termios->c_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, termios->c_cflag))
                up->ier |= UART_IER_MSI;

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

        spin_unlock_irqrestore(&up->port.lock, flags);
}

/*
 * Resource handling.  This is complicated by the fact that resources
 * depend on the port type.  Maybe we should be claiming the standard
 * 8250 ports, and then trying to get other resources as necessary?
 */
static int
m32r_sio_request_std_resource(struct uart_sio_port *up, struct resource **res)
{
        unsigned int size = 8 << up->port.regshift;
#ifndef CONFIG_SERIAL_M32R_PLDSIO
        unsigned long start;
#endif
        int ret = 0;

        switch (up->port.iotype) {
        case UPIO_MEM:
                if (up->port.mapbase) {
#ifdef CONFIG_SERIAL_M32R_PLDSIO
                        *res = request_mem_region(up->port.mapbase, size, "serial");
#else
                        start = up->port.mapbase;
                        *res = request_mem_region(start, size, "serial");
#endif
                        if (!*res)
                                ret = -EBUSY;
                }
                break;

        case UPIO_PORT:
                *res = request_region(up->port.iobase, size, "serial");
                if (!*res)
                        ret = -EBUSY;
                break;
        }
        return ret;
}

static void m32r_sio_release_port(struct uart_port *port)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);
        unsigned long start, offset = 0, size = 0;

        size <<= up->port.regshift;

        switch (up->port.iotype) {
        case UPIO_MEM:
                if (up->port.mapbase) {
                        /*
                         * Unmap the area.
                         */
                        iounmap(up->port.membase);
                        up->port.membase = NULL;

                        start = up->port.mapbase;

                        if (size)
                                release_mem_region(start + offset, size);
                        release_mem_region(start, 8 << up->port.regshift);
                }
                break;

        case UPIO_PORT:
                start = up->port.iobase;

                if (size)
                        release_region(start + offset, size);
                release_region(start + offset, 8 << up->port.regshift);
                break;

        default:
                break;
        }
}

static int m32r_sio_request_port(struct uart_port *port)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);
        struct resource *res = NULL;
        int ret = 0;

        ret = m32r_sio_request_std_resource(up, &res);

        /*
         * If we have a mapbase, then request that as well.
         */
        if (ret == 0 && up->port.flags & UPF_IOREMAP) {
                int size = resource_size(res);

                up->port.membase = ioremap(up->port.mapbase, size);
                if (!up->port.membase)
                        ret = -ENOMEM;
        }

        if (ret < 0) {
                if (res)
                        release_resource(res);
        }

        return ret;
}

static void m32r_sio_config_port(struct uart_port *port, int unused)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);
        unsigned long flags;

        spin_lock_irqsave(&up->port.lock, flags);

        up->port.fifosize = 1;

        spin_unlock_irqrestore(&up->port.lock, flags);
}

static int
m32r_sio_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        if (ser->irq >= nr_irqs || ser->irq < 0 || ser->baud_base < 9600)
                return -EINVAL;
        return 0;
}

static const struct uart_ops m32r_sio_pops = {
        .tx_empty       = m32r_sio_tx_empty,
        .set_mctrl      = m32r_sio_set_mctrl,
        .get_mctrl      = m32r_sio_get_mctrl,
        .stop_tx        = m32r_sio_stop_tx,
        .start_tx       = m32r_sio_start_tx,
        .stop_rx        = m32r_sio_stop_rx,
        .enable_ms      = m32r_sio_enable_ms,
        .break_ctl      = m32r_sio_break_ctl,
        .startup        = m32r_sio_startup,
        .shutdown       = m32r_sio_shutdown,
        .set_termios    = m32r_sio_set_termios,
        .release_port   = m32r_sio_release_port,
        .request_port   = m32r_sio_request_port,
        .config_port    = m32r_sio_config_port,
        .verify_port    = m32r_sio_verify_port,
};

static struct uart_sio_port m32r_sio_ports[UART_NR];

static void __init m32r_sio_init_ports(void)
{
        struct uart_sio_port *up;
        static int first = 1;
        int i;

        if (!first)
                return;
        first = 0;

        for (i = 0, up = m32r_sio_ports; i < UART_NR; i++, up++) {
                up->port.iobase   = old_serial_port[i].port;
                up->port.irq      = irq_canonicalize(old_serial_port[i].irq);
                up->port.uartclk  = BAUD_RATE * 16;
                up->port.flags    = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST;
                up->port.membase  = 0;
                up->port.iotype   = 0;
                up->port.regshift = 0;
                up->port.ops      = &m32r_sio_pops;
        }
}

static void __init m32r_sio_register_ports(struct uart_driver *drv)
{
        int i;

        m32r_sio_init_ports();

        for (i = 0; i < UART_NR; i++) {
                struct uart_sio_port *up = &m32r_sio_ports[i];

                up->port.line = i;
                up->port.ops = &m32r_sio_pops;
                timer_setup(&up->timer, m32r_sio_timeout, 0);

                uart_add_one_port(drv, &up->port);
        }
}

#ifdef CONFIG_SERIAL_M32R_SIO_CONSOLE

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

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

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

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

static void m32r_sio_console_putchar(struct uart_port *port, int ch)
{
        struct uart_sio_port *up =
                container_of(port, struct uart_sio_port, port);

        wait_for_xmitr(up);
        sio_out(up, SIOTXB, ch);
}

/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 *
 *      The console_lock must be held when we get here.
 */
static void m32r_sio_console_write(struct console *co, const char *s,
        unsigned int count)
{
        struct uart_sio_port *up = &m32r_sio_ports[co->index];
        unsigned int ier;

        /*
         *      First save the UER then disable the interrupts
         */
        ier = sio_in(up, SIOTRCR);
        sio_out(up, SIOTRCR, 0);

        uart_console_write(&up->port, s, count, m32r_sio_console_putchar);

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

static int __init m32r_sio_console_setup(struct console *co, char *options)
{
        struct uart_port *port;
        int baud = 9600;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        /*
         * Check whether an invalid uart number has been specified, and
         * if so, search for the first available port that does have
         * console support.
         */
        if (co->index >= UART_NR)
                co->index = 0;
        port = &m32r_sio_ports[co->index].port;

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

        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);

        return uart_set_options(port, co, baud, parity, bits, flow);
}

static struct uart_driver m32r_sio_reg;
static struct console m32r_sio_console = {
        .name           = "ttyS",
        .write          = m32r_sio_console_write,
        .device         = uart_console_device,
        .setup          = m32r_sio_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &m32r_sio_reg,
};

static int __init m32r_sio_console_init(void)
{
        sio_reset();
        sio_init();
        m32r_sio_init_ports();
        register_console(&m32r_sio_console);
        return 0;
}
console_initcall(m32r_sio_console_init);

#define M32R_SIO_CONSOLE        &m32r_sio_console
#else
#define M32R_SIO_CONSOLE        NULL
#endif

static struct uart_driver m32r_sio_reg = {
        .owner                  = THIS_MODULE,
        .driver_name            = "sio",
        .dev_name               = "ttyS",
        .major                  = TTY_MAJOR,
        .minor                  = 64,
        .nr                     = UART_NR,
        .cons                   = M32R_SIO_CONSOLE,
};

static int __init m32r_sio_init(void)
{
        int ret, i;

        printk(KERN_INFO "Serial: M32R SIO driver\n");

        for (i = 0; i < nr_irqs; i++)
                spin_lock_init(&irq_lists[i].lock);

        ret = uart_register_driver(&m32r_sio_reg);
        if (ret >= 0)
                m32r_sio_register_ports(&m32r_sio_reg);

        return ret;
}
device_initcall(m32r_sio_init);