/*
 * drivers/serial/sh-sci.c
 *
 * SuperH on-chip serial module support.  (SCI with no FIFO / with FIFO)
 *
 *  Copyright (C) 2002 - 2008  Paul Mundt
 *  Modified to support SH7720 SCIF. Markus Brunner, Mark Jonas (Jul 2007).
 *
 * based off of the old drivers/char/sh-sci.c by:
 *
 *   Copyright (C) 1999, 2000  Niibe Yutaka
 *   Copyright (C) 2000  Sugioka Toshinobu
 *   Modified to support multiple serial ports. Stuart Menefy (May 2000).
 *   Modified to support SecureEdge. David McCullough (2002)
 *   Modified to support SH7300 SCIF. Takashi Kusuda (Jun 2003).
 *   Removed SH7300 support (Jul 2007).
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#undef DEBUG

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/sysrq.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/console.h>
#include <linux/platform_device.h>
#include <linux/serial_sci.h>
#include <linux/notifier.h>
#include <linux/cpufreq.h>
#include <linux/clk.h>
#include <linux/ctype.h>
#include <linux/err.h>

#ifdef CONFIG_SUPERH
#include <asm/clock.h>
#include <asm/sh_bios.h>
#include <asm/kgdb.h>
#endif

#include "sh-sci.h"

struct sci_port {
        struct uart_port        port;

        /* Port type */
        unsigned int            type;

        /* Port IRQs: ERI, RXI, TXI, BRI (optional) */
        unsigned int            irqs[SCIx_NR_IRQS];

        /* Port pin configuration */
        void                    (*init_pins)(struct uart_port *port,
                                             unsigned int cflag);

        /* Port enable callback */
        void                    (*enable)(struct uart_port *port);

        /* Port disable callback */
        void                    (*disable)(struct uart_port *port);

        /* Break timer */
        struct timer_list       break_timer;
        int                     break_flag;

#ifdef CONFIG_HAVE_CLK
        /* Port clock */
        struct clk              *clk;
#endif
};

#ifdef CONFIG_SH_KGDB
static struct sci_port *kgdb_sci_port;
#endif

#ifdef CONFIG_SERIAL_SH_SCI_CONSOLE
static struct sci_port *serial_console_port;
#endif

/* Function prototypes */
static void sci_stop_tx(struct uart_port *port);

#define SCI_NPORTS CONFIG_SERIAL_SH_SCI_NR_UARTS

static struct sci_port sci_ports[SCI_NPORTS];
static struct uart_driver sci_uart_driver;

#if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) && \
    defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
static inline void handle_error(struct uart_port *port)
{
        /* Clear error flags */
        sci_out(port, SCxSR, SCxSR_ERROR_CLEAR(port));
}

static int get_char(struct uart_port *port)
{
        unsigned long flags;
        unsigned short status;
        int c;

        spin_lock_irqsave(&port->lock, flags);
        do {
                status = sci_in(port, SCxSR);
                if (status & SCxSR_ERRORS(port)) {
                        handle_error(port);
                        continue;
                }
        } while (!(status & SCxSR_RDxF(port)));
        c = sci_in(port, SCxRDR);
        sci_in(port, SCxSR);            /* Dummy read */
        sci_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
        spin_unlock_irqrestore(&port->lock, flags);

        return c;
}
#endif /* CONFIG_SH_STANDARD_BIOS || CONFIG_SH_KGDB */

#if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) || defined(CONFIG_SH_KGDB)
static void put_char(struct uart_port *port, char c)
{
        unsigned long flags;
        unsigned short status;

        spin_lock_irqsave(&port->lock, flags);

        do {
                status = sci_in(port, SCxSR);
        } while (!(status & SCxSR_TDxE(port)));

        sci_in(port, SCxSR);            /* Dummy read */
        sci_out(port, SCxSR, SCxSR_TDxE_CLEAR(port));
        sci_out(port, SCxTDR, c);

        spin_unlock_irqrestore(&port->lock, flags);
}
#endif

#ifdef CONFIG_SERIAL_SH_SCI_CONSOLE
static void put_string(struct sci_port *sci_port, const char *buffer, int count)
{
        struct uart_port *port = &sci_port->port;
        const unsigned char *p = buffer;
        int i;

#if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
        int checksum;
        int usegdb=0;

#ifdef CONFIG_SH_STANDARD_BIOS
        /* This call only does a trap the first time it is
         * called, and so is safe to do here unconditionally
         */
        usegdb |= sh_bios_in_gdb_mode();
#endif
#ifdef CONFIG_SH_KGDB
        usegdb |= (kgdb_in_gdb_mode && (sci_port == kgdb_sci_port));
#endif

        if (usegdb) {
            /*  $<packet info>#<checksum>. */
            do {
                unsigned char c;
                put_char(port, '$');
                put_char(port, 'O'); /* 'O'utput to console */
                checksum = 'O';

                for (i=0; i<count; i++) { /* Don't use run length encoding */
                        int h, l;

                        c = *p++;
                        h = hex_asc_hi(c);
                        l = hex_asc_lo(c);
                        put_char(port, h);
                        put_char(port, l);
                        checksum += h + l;
                }
                put_char(port, '#');
                put_char(port, hex_asc_hi(checksum));
                put_char(port, hex_asc_lo(checksum));
            } while  (get_char(port) != '+');
        } else
#endif /* CONFIG_SH_STANDARD_BIOS || CONFIG_SH_KGDB */
        for (i=0; i<count; i++) {
                if (*p == 10)
                        put_char(port, '\r');
                put_char(port, *p++);
        }
}
#endif /* CONFIG_SERIAL_SH_SCI_CONSOLE */

#ifdef CONFIG_SH_KGDB
static int kgdb_sci_getchar(void)
{
        int c;

        /* Keep trying to read a character, this could be neater */
        while ((c = get_char(&kgdb_sci_port->port)) < 0)
                cpu_relax();

        return c;
}

static inline void kgdb_sci_putchar(int c)
{
        put_char(&kgdb_sci_port->port, c);
}
#endif /* CONFIG_SH_KGDB */

#if defined(__H8300S__)
enum { sci_disable, sci_enable };

static void h8300_sci_config(struct uart_port* port, unsigned int ctrl)
{
        volatile unsigned char *mstpcrl=(volatile unsigned char *)MSTPCRL;
        int ch = (port->mapbase  - SMR0) >> 3;
        unsigned char mask = 1 << (ch+1);

        if (ctrl == sci_disable) {
                *mstpcrl |= mask;
        } else {
                *mstpcrl &= ~mask;
        }
}

static inline void h8300_sci_enable(struct uart_port *port)
{
        h8300_sci_config(port, sci_enable);
}

static inline void h8300_sci_disable(struct uart_port *port)
{
        h8300_sci_config(port, sci_disable);
}
#endif

#if defined(__H8300H__) || defined(__H8300S__)
static void sci_init_pins_sci(struct uart_port* port, unsigned int cflag)
{
        int ch = (port->mapbase - SMR0) >> 3;

        /* set DDR regs */
        H8300_GPIO_DDR(h8300_sci_pins[ch].port,
                       h8300_sci_pins[ch].rx,
                       H8300_GPIO_INPUT);
        H8300_GPIO_DDR(h8300_sci_pins[ch].port,
                       h8300_sci_pins[ch].tx,
                       H8300_GPIO_OUTPUT);

        /* tx mark output*/
        H8300_SCI_DR(ch) |= h8300_sci_pins[ch].tx;
}
#else
#define sci_init_pins_sci NULL
#endif

#if defined(CONFIG_CPU_SUBTYPE_SH7707) || defined(CONFIG_CPU_SUBTYPE_SH7709)
static void sci_init_pins_irda(struct uart_port *port, unsigned int cflag)
{
        unsigned int fcr_val = 0;

        if (cflag & CRTSCTS)
                fcr_val |= SCFCR_MCE;

        sci_out(port, SCFCR, fcr_val);
}
#else
#define sci_init_pins_irda NULL
#endif

#if defined(CONFIG_CPU_SUBTYPE_SH7710) || defined(CONFIG_CPU_SUBTYPE_SH7712)
static void sci_init_pins_scif(struct uart_port* port, unsigned int cflag)
{
        unsigned int fcr_val = 0;

        set_sh771x_scif_pfc(port);
        if (cflag & CRTSCTS) {
                fcr_val |= SCFCR_MCE;
        }
        sci_out(port, SCFCR, fcr_val);
}
#elif defined(CONFIG_CPU_SUBTYPE_SH7720) || defined(CONFIG_CPU_SUBTYPE_SH7721)
static void sci_init_pins_scif(struct uart_port *port, unsigned int cflag)
{
        unsigned int fcr_val = 0;
        unsigned short data;

        if (cflag & CRTSCTS) {
                /* enable RTS/CTS */
                if (port->mapbase == 0xa4430000) { /* SCIF0 */
                        /* Clear PTCR bit 9-2; enable all scif pins but sck */
                        data = ctrl_inw(PORT_PTCR);
                        ctrl_outw((data & 0xfc03), PORT_PTCR);
                } else if (port->mapbase == 0xa4438000) { /* SCIF1 */
                        /* Clear PVCR bit 9-2 */
                        data = ctrl_inw(PORT_PVCR);
                        ctrl_outw((data & 0xfc03), PORT_PVCR);
                }
                fcr_val |= SCFCR_MCE;
        } else {
                if (port->mapbase == 0xa4430000) { /* SCIF0 */
                        /* Clear PTCR bit 5-2; enable only tx and rx  */
                        data = ctrl_inw(PORT_PTCR);
                        ctrl_outw((data & 0xffc3), PORT_PTCR);
                } else if (port->mapbase == 0xa4438000) { /* SCIF1 */
                        /* Clear PVCR bit 5-2 */
                        data = ctrl_inw(PORT_PVCR);
                        ctrl_outw((data & 0xffc3), PORT_PVCR);
                }
        }
        sci_out(port, SCFCR, fcr_val);
}
#elif defined(CONFIG_CPU_SH3)
/* For SH7705, SH7706, SH7707, SH7709, SH7709A, SH7729 */
static void sci_init_pins_scif(struct uart_port *port, unsigned int cflag)
{
        unsigned int fcr_val = 0;
        unsigned short data;

        /* We need to set SCPCR to enable RTS/CTS */
        data = ctrl_inw(SCPCR);
        /* Clear out SCP7MD1,0, SCP6MD1,0, SCP4MD1,0*/
        ctrl_outw(data & 0x0fcf, SCPCR);

        if (cflag & CRTSCTS)
                fcr_val |= SCFCR_MCE;
        else {
                /* We need to set SCPCR to enable RTS/CTS */
                data = ctrl_inw(SCPCR);
                /* Clear out SCP7MD1,0, SCP4MD1,0,
                   Set SCP6MD1,0 = {01} (output)  */
                ctrl_outw((data & 0x0fcf) | 0x1000, SCPCR);

                data = ctrl_inb(SCPDR);
                /* Set /RTS2 (bit6) = 0 */
                ctrl_outb(data & 0xbf, SCPDR);
        }

        sci_out(port, SCFCR, fcr_val);
}
#elif defined(CONFIG_CPU_SUBTYPE_SH7722)
static void sci_init_pins_scif(struct uart_port *port, unsigned int cflag)
{
        unsigned int fcr_val = 0;
        unsigned short data;

        if (port->mapbase == 0xffe00000) {
                data = ctrl_inw(PSCR);
                data &= ~0x03cf;
                if (cflag & CRTSCTS)
                        fcr_val |= SCFCR_MCE;
                else
                        data |= 0x0340;

                ctrl_outw(data, PSCR);
        }
        /* SCIF1 and SCIF2 should be setup by board code */

        sci_out(port, SCFCR, fcr_val);
}
#elif defined(CONFIG_CPU_SUBTYPE_SH7723)
static void sci_init_pins_scif(struct uart_port *port, unsigned int cflag)
{
        /* Nothing to do here.. */
        sci_out(port, SCFCR, 0);
}
#else
/* For SH7750 */
static void sci_init_pins_scif(struct uart_port *port, unsigned int cflag)
{
        unsigned int fcr_val = 0;

        if (cflag & CRTSCTS) {
                fcr_val |= SCFCR_MCE;
        } else {
#if defined(CONFIG_CPU_SUBTYPE_SH7343) || defined(CONFIG_CPU_SUBTYPE_SH7366)
                /* Nothing */
#elif defined(CONFIG_CPU_SUBTYPE_SH7763) || \
      defined(CONFIG_CPU_SUBTYPE_SH7780) || \
      defined(CONFIG_CPU_SUBTYPE_SH7785) || \
      defined(CONFIG_CPU_SUBTYPE_SHX3)
                ctrl_outw(0x0080, SCSPTR0); /* Set RTS = 1 */
#else
                ctrl_outw(0x0080, SCSPTR2); /* Set RTS = 1 */
#endif
        }
        sci_out(port, SCFCR, fcr_val);
}
#endif

#if defined(CONFIG_CPU_SUBTYPE_SH7760) || \
    defined(CONFIG_CPU_SUBTYPE_SH7780) || \
    defined(CONFIG_CPU_SUBTYPE_SH7785)
static inline int scif_txroom(struct uart_port *port)
{
        return SCIF_TXROOM_MAX - (sci_in(port, SCTFDR) & 0xff);
}

static inline int scif_rxroom(struct uart_port *port)
{
        return sci_in(port, SCRFDR) & 0xff;
}
#elif defined(CONFIG_CPU_SUBTYPE_SH7763)
static inline int scif_txroom(struct uart_port *port)
{
        if((port->mapbase == 0xffe00000) || (port->mapbase == 0xffe08000)) /* SCIF0/1*/
                return SCIF_TXROOM_MAX - (sci_in(port, SCTFDR) & 0xff);
        else /* SCIF2 */
                return SCIF2_TXROOM_MAX - (sci_in(port, SCFDR) >> 8);
}

static inline int scif_rxroom(struct uart_port *port)
{
        if((port->mapbase == 0xffe00000) || (port->mapbase == 0xffe08000)) /* SCIF0/1*/
                return sci_in(port, SCRFDR) & 0xff;
        else /* SCIF2 */
                return sci_in(port, SCFDR) & SCIF2_RFDC_MASK;
}
#else
static inline int scif_txroom(struct uart_port *port)
{
        return SCIF_TXROOM_MAX - (sci_in(port, SCFDR) >> 8);
}

static inline int scif_rxroom(struct uart_port *port)
{
        return sci_in(port, SCFDR) & SCIF_RFDC_MASK;
}
#endif

static inline int sci_txroom(struct uart_port *port)
{
        return ((sci_in(port, SCxSR) & SCI_TDRE) != 0);
}

static inline int sci_rxroom(struct uart_port *port)
{
        return ((sci_in(port, SCxSR) & SCxSR_RDxF(port)) != 0);
}

/* ********************************************************************** *
 *                   the interrupt related routines                       *
 * ********************************************************************** */

static void sci_transmit_chars(struct uart_port *port)
{
        struct circ_buf *xmit = &port->info->xmit;
        unsigned int stopped = uart_tx_stopped(port);
        unsigned short status;
        unsigned short ctrl;
        int count;

        status = sci_in(port, SCxSR);
        if (!(status & SCxSR_TDxE(port))) {
                ctrl = sci_in(port, SCSCR);
                if (uart_circ_empty(xmit)) {
                        ctrl &= ~SCI_CTRL_FLAGS_TIE;
                } else {
                        ctrl |= SCI_CTRL_FLAGS_TIE;
                }
                sci_out(port, SCSCR, ctrl);
                return;
        }

        if (port->type == PORT_SCI)
                count = sci_txroom(port);
        else
                count = scif_txroom(port);

        do {
                unsigned char c;

                if (port->x_char) {
                        c = port->x_char;
                        port->x_char = 0;
                } else if (!uart_circ_empty(xmit) && !stopped) {
                        c = xmit->buf[xmit->tail];
                        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                } else {
                        break;
                }

                sci_out(port, SCxTDR, c);

                port->icount.tx++;
        } while (--count > 0);

        sci_out(port, SCxSR, SCxSR_TDxE_CLEAR(port));

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(port);
        if (uart_circ_empty(xmit)) {
                sci_stop_tx(port);
        } else {
                ctrl = sci_in(port, SCSCR);

                if (port->type != PORT_SCI) {
                        sci_in(port, SCxSR); /* Dummy read */
                        sci_out(port, SCxSR, SCxSR_TDxE_CLEAR(port));
                }

                ctrl |= SCI_CTRL_FLAGS_TIE;
                sci_out(port, SCSCR, ctrl);
        }
}

/* On SH3, SCIF may read end-of-break as a space->mark char */
#define STEPFN(c)  ({int __c=(c); (((__c-1)|(__c)) == -1); })

static inline void sci_receive_chars(struct uart_port *port)
{
        struct sci_port *sci_port = (struct sci_port *)port;
        struct tty_struct *tty = port->info->port.tty;
        int i, count, copied = 0;
        unsigned short status;
        unsigned char flag;

        status = sci_in(port, SCxSR);
        if (!(status & SCxSR_RDxF(port)))
                return;

        while (1) {
                if (port->type == PORT_SCI)
                        count = sci_rxroom(port);
                else
                        count = scif_rxroom(port);

                /* Don't copy more bytes than there is room for in the buffer */
                count = tty_buffer_request_room(tty, count);

                /* If for any reason we can't copy more data, we're done! */
                if (count == 0)
                        break;

                if (port->type == PORT_SCI) {
                        char c = sci_in(port, SCxRDR);
                        if (uart_handle_sysrq_char(port, c) || sci_port->break_flag)
                                count = 0;
                        else {
                                tty_insert_flip_char(tty, c, TTY_NORMAL);
                        }
                } else {
                        for (i=0; i<count; i++) {
                                char c = sci_in(port, SCxRDR);
                                status = sci_in(port, SCxSR);
#if defined(CONFIG_CPU_SH3)
                                /* Skip "chars" during break */
                                if (sci_port->break_flag) {
                                        if ((c == 0) &&
                                            (status & SCxSR_FER(port))) {
                                                count--; i--;
                                                continue;
                                        }

                                        /* Nonzero => end-of-break */
                                        pr_debug("scif: debounce<%02x>\n", c);
                                        sci_port->break_flag = 0;

                                        if (STEPFN(c)) {
                                                count--; i--;
                                                continue;
                                        }
                                }
#endif /* CONFIG_CPU_SH3 */
                                if (uart_handle_sysrq_char(port, c)) {
                                        count--; i--;
                                        continue;
                                }

                                /* Store data and status */
                                if (status&SCxSR_FER(port)) {
                                        flag = TTY_FRAME;
                                        pr_debug("sci: frame error\n");
                                } else if (status&SCxSR_PER(port)) {
                                        flag = TTY_PARITY;
                                        pr_debug("sci: parity error\n");
                                } else
                                        flag = TTY_NORMAL;
                                tty_insert_flip_char(tty, c, flag);
                        }
                }

                sci_in(port, SCxSR); /* dummy read */
                sci_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));

                copied += count;
                port->icount.rx += count;
        }

        if (copied) {
                /* Tell the rest of the system the news. New characters! */
                tty_flip_buffer_push(tty);
        } else {
                sci_in(port, SCxSR); /* dummy read */
                sci_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
        }
}

#define SCI_BREAK_JIFFIES (HZ/20)
/* The sci generates interrupts during the break,
 * 1 per millisecond or so during the break period, for 9600 baud.
 * So dont bother disabling interrupts.
 * But dont want more than 1 break event.
 * Use a kernel timer to periodically poll the rx line until
 * the break is finished.
 */
static void sci_schedule_break_timer(struct sci_port *port)
{
        port->break_timer.expires = jiffies + SCI_BREAK_JIFFIES;
        add_timer(&port->break_timer);
}
/* Ensure that two consecutive samples find the break over. */
static void sci_break_timer(unsigned long data)
{
        struct sci_port *port = (struct sci_port *)data;

        if (sci_rxd_in(&port->port) == 0) {
                port->break_flag = 1;
                sci_schedule_break_timer(port);
        } else if (port->break_flag == 1) {
                /* break is over. */
                port->break_flag = 2;
                sci_schedule_break_timer(port);
        } else
                port->break_flag = 0;
}

static inline int sci_handle_errors(struct uart_port *port)
{
        int copied = 0;
        unsigned short status = sci_in(port, SCxSR);
        struct tty_struct *tty = port->info->port.tty;

        if (status & SCxSR_ORER(port)) {
                /* overrun error */
                if (tty_insert_flip_char(tty, 0, TTY_OVERRUN))
                        copied++;
                pr_debug("sci: overrun error\n");
        }

        if (status & SCxSR_FER(port)) {
                if (sci_rxd_in(port) == 0) {
                        /* Notify of BREAK */
                        struct sci_port *sci_port = (struct sci_port *)port;

                        if (!sci_port->break_flag) {
                                sci_port->break_flag = 1;
                                sci_schedule_break_timer(sci_port);

                                /* Do sysrq handling. */
                                if (uart_handle_break(port))
                                        return 0;
                                pr_debug("sci: BREAK detected\n");
                                if (tty_insert_flip_char(tty, 0, TTY_BREAK))
                                        copied++;
                       }
                } else {
                        /* frame error */
                        if (tty_insert_flip_char(tty, 0, TTY_FRAME))
                                copied++;
                        pr_debug("sci: frame error\n");
                }
        }

        if (status & SCxSR_PER(port)) {
                /* parity error */
                if (tty_insert_flip_char(tty, 0, TTY_PARITY))
                        copied++;
                pr_debug("sci: parity error\n");
        }

        if (copied)
                tty_flip_buffer_push(tty);

        return copied;
}

static inline int sci_handle_breaks(struct uart_port *port)
{
        int copied = 0;
        unsigned short status = sci_in(port, SCxSR);
        struct tty_struct *tty = port->info->port.tty;
        struct sci_port *s = &sci_ports[port->line];

        if (uart_handle_break(port))
                return 0;

        if (!s->break_flag && status & SCxSR_BRK(port)) {
#if defined(CONFIG_CPU_SH3)
                /* Debounce break */
                s->break_flag = 1;
#endif
                /* Notify of BREAK */
                if (tty_insert_flip_char(tty, 0, TTY_BREAK))
                        copied++;
                pr_debug("sci: BREAK detected\n");
        }

#if defined(SCIF_ORER)
        /* XXX: Handle SCIF overrun error */
        if (port->type != PORT_SCI && (sci_in(port, SCLSR) & SCIF_ORER) != 0) {
                sci_out(port, SCLSR, 0);
                if (tty_insert_flip_char(tty, 0, TTY_OVERRUN)) {
                        copied++;
                        pr_debug("sci: overrun error\n");
                }
        }
#endif

        if (copied)
                tty_flip_buffer_push(tty);

        return copied;
}

static irqreturn_t sci_rx_interrupt(int irq, void *port)
{
        /* I think sci_receive_chars has to be called irrespective
         * of whether the I_IXOFF is set, otherwise, how is the interrupt
         * to be disabled?
         */
        sci_receive_chars(port);

        return IRQ_HANDLED;
}

static irqreturn_t sci_tx_interrupt(int irq, void *ptr)
{
        struct uart_port *port = ptr;

        spin_lock_irq(&port->lock);
        sci_transmit_chars(port);
        spin_unlock_irq(&port->lock);

        return IRQ_HANDLED;
}

static irqreturn_t sci_er_interrupt(int irq, void *ptr)
{
        struct uart_port *port = ptr;

        /* Handle errors */
        if (port->type == PORT_SCI) {
                if (sci_handle_errors(port)) {
                        /* discard character in rx buffer */
                        sci_in(port, SCxSR);
                        sci_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
                }
        } else {
#if defined(SCIF_ORER)
                if((sci_in(port, SCLSR) & SCIF_ORER) != 0) {
                        struct tty_struct *tty = port->info->port.tty;

                        sci_out(port, SCLSR, 0);
                        tty_insert_flip_char(tty, 0, TTY_OVERRUN);
                        tty_flip_buffer_push(tty);
                        pr_debug("scif: overrun error\n");
                }
#endif
                sci_rx_interrupt(irq, ptr);
        }

        sci_out(port, SCxSR, SCxSR_ERROR_CLEAR(port));

        /* Kick the transmission */
        sci_tx_interrupt(irq, ptr);

        return IRQ_HANDLED;
}

static irqreturn_t sci_br_interrupt(int irq, void *ptr)
{
        struct uart_port *port = ptr;

        /* Handle BREAKs */
        sci_handle_breaks(port);
        sci_out(port, SCxSR, SCxSR_BREAK_CLEAR(port));

        return IRQ_HANDLED;
}

static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
{
        unsigned short ssr_status, scr_status;
        struct uart_port *port = ptr;
        irqreturn_t ret = IRQ_NONE;

        ssr_status = sci_in(port,SCxSR);
        scr_status = sci_in(port,SCSCR);

        /* Tx Interrupt */
        if ((ssr_status & 0x0020) && (scr_status & SCI_CTRL_FLAGS_TIE))
                ret = sci_tx_interrupt(irq, ptr);
        /* Rx Interrupt */
        if ((ssr_status & 0x0002) && (scr_status & SCI_CTRL_FLAGS_RIE))
                ret = sci_rx_interrupt(irq, ptr);
        /* Error Interrupt */
        if ((ssr_status & 0x0080) && (scr_status & SCI_CTRL_FLAGS_REIE))
                ret = sci_er_interrupt(irq, ptr);
        /* Break Interrupt */
        if ((ssr_status & 0x0010) && (scr_status & SCI_CTRL_FLAGS_REIE))
                ret = sci_br_interrupt(irq, ptr);

        return ret;
}

#if defined(CONFIG_CPU_FREQ) && defined(CONFIG_HAVE_CLK)
/*
 * Here we define a transistion notifier so that we can update all of our
 * ports' baud rate when the peripheral clock changes.
 */
static int sci_notifier(struct notifier_block *self,
                        unsigned long phase, void *p)
{
        struct cpufreq_freqs *freqs = p;
        int i;

        if ((phase == CPUFREQ_POSTCHANGE) ||
            (phase == CPUFREQ_RESUMECHANGE)){
                for (i = 0; i < SCI_NPORTS; i++) {
                        struct uart_port *port = &sci_ports[i].port;
                        struct clk *clk;

                        /*
                         * Update the uartclk per-port if frequency has
                         * changed, since it will no longer necessarily be
                         * consistent with the old frequency.
                         *
                         * Really we want to be able to do something like
                         * uart_change_speed() or something along those lines
                         * here to implicitly reset the per-port baud rate..
                         *
                         * Clean this up later..
                         */
                        clk = clk_get(NULL, "module_clk");
                        port->uartclk = clk_get_rate(clk);
                        clk_put(clk);
                }

                printk(KERN_INFO "%s: got a postchange notification "
                       "for cpu %d (old %d, new %d)\n",
                       __func__, freqs->cpu, freqs->old, freqs->new);
        }

        return NOTIFY_OK;
}

static struct notifier_block sci_nb = { &sci_notifier, NULL, 0 };
#endif /* CONFIG_CPU_FREQ && CONFIG_HAVE_CLK */

static int sci_request_irq(struct sci_port *port)
{
        int i;
        irqreturn_t (*handlers[4])(int irq, void *ptr) = {
                sci_er_interrupt, sci_rx_interrupt, sci_tx_interrupt,
                sci_br_interrupt,
        };
        const char *desc[] = { "SCI Receive Error", "SCI Receive Data Full",
                               "SCI Transmit Data Empty", "SCI Break" };

        if (port->irqs[0] == port->irqs[1]) {
                if (!port->irqs[0]) {
                        printk(KERN_ERR "sci: Cannot allocate irq.(IRQ=0)\n");
                        return -ENODEV;
                }

                if (request_irq(port->irqs[0], sci_mpxed_interrupt,
                                IRQF_DISABLED, "sci", port)) {
                        printk(KERN_ERR "sci: Cannot allocate irq.\n");
                        return -ENODEV;
                }
        } else {
                for (i = 0; i < ARRAY_SIZE(handlers); i++) {
                        if (!port->irqs[i])
                                continue;
                        if (request_irq(port->irqs[i], handlers[i],
                                        IRQF_DISABLED, desc[i], port)) {
                                printk(KERN_ERR "sci: Cannot allocate irq.\n");
                                return -ENODEV;
                        }
                }
        }

        return 0;
}

static void sci_free_irq(struct sci_port *port)
{
        int i;

        if (port->irqs[0] == port->irqs[1]) {
                if (!port->irqs[0])
                        printk("sci: sci_free_irq error\n");
                else
                        free_irq(port->irqs[0], port);
        } else {
                for (i = 0; i < ARRAY_SIZE(port->irqs); i++) {
                        if (!port->irqs[i])
                                continue;

                        free_irq(port->irqs[i], port);
                }
        }
}

static unsigned int sci_tx_empty(struct uart_port *port)
{
        /* Can't detect */
        return TIOCSER_TEMT;
}

static void sci_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        /* This routine is used for seting signals of: DTR, DCD, CTS/RTS */
        /* We use SCIF's hardware for CTS/RTS, so don't need any for that. */
        /* If you have signals for DTR and DCD, please implement here. */
}

static unsigned int sci_get_mctrl(struct uart_port *port)
{
        /* This routine is used for geting signals of: DTR, DCD, DSR, RI,
           and CTS/RTS */

        return TIOCM_DTR | TIOCM_RTS | TIOCM_DSR;
}

static void sci_start_tx(struct uart_port *port)
{
        unsigned short ctrl;

        /* Set TIE (Transmit Interrupt Enable) bit in SCSCR */
        ctrl = sci_in(port, SCSCR);
        ctrl |= SCI_CTRL_FLAGS_TIE;
        sci_out(port, SCSCR, ctrl);
}

static void sci_stop_tx(struct uart_port *port)
{
        unsigned short ctrl;

        /* Clear TIE (Transmit Interrupt Enable) bit in SCSCR */
        ctrl = sci_in(port, SCSCR);
        ctrl &= ~SCI_CTRL_FLAGS_TIE;
        sci_out(port, SCSCR, ctrl);
}

static void sci_start_rx(struct uart_port *port, unsigned int tty_start)
{
        unsigned short ctrl;

        /* Set RIE (Receive Interrupt Enable) bit in SCSCR */
        ctrl = sci_in(port, SCSCR);
        ctrl |= SCI_CTRL_FLAGS_RIE | SCI_CTRL_FLAGS_REIE;
        sci_out(port, SCSCR, ctrl);
}

static void sci_stop_rx(struct uart_port *port)
{
        unsigned short ctrl;

        /* Clear RIE (Receive Interrupt Enable) bit in SCSCR */
        ctrl = sci_in(port, SCSCR);
        ctrl &= ~(SCI_CTRL_FLAGS_RIE | SCI_CTRL_FLAGS_REIE);
        sci_out(port, SCSCR, ctrl);
}

static void sci_enable_ms(struct uart_port *port)
{
        /* Nothing here yet .. */
}

static void sci_break_ctl(struct uart_port *port, int break_state)
{
        /* Nothing here yet .. */
}

static int sci_startup(struct uart_port *port)
{
        struct sci_port *s = &sci_ports[port->line];

        if (s->enable)
                s->enable(port);

#ifdef CONFIG_HAVE_CLK

        s->clk = clk_get(NULL, "module_clk");
#endif

        sci_request_irq(s);
        sci_start_tx(port);
        sci_start_rx(port, 1);

        return 0;
}

static void sci_shutdown(struct uart_port *port)
{
        struct sci_port *s = &sci_ports[port->line];

        sci_stop_rx(port);
        sci_stop_tx(port);
        sci_free_irq(s);

        if (s->disable)
                s->disable(port);

#ifdef CONFIG_HAVE_CLK
        clk_put(s->clk);
        s->clk = NULL;
#endif
}

static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
                            struct ktermios *old)
{
        struct sci_port *s = &sci_ports[port->line];
        unsigned int status, baud, smr_val;
        int t = -1;

        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
        if (likely(baud))
                t = SCBRR_VALUE(baud, port->uartclk);

        do {
                status = sci_in(port, SCxSR);
        } while (!(status & SCxSR_TEND(port)));

        sci_out(port, SCSCR, 0x00);     /* TE=0, RE=0, CKE1=0 */

        if (port->type != PORT_SCI)
                sci_out(port, SCFCR, SCFCR_RFRST | SCFCR_TFRST);

        smr_val = sci_in(port, SCSMR) & 3;
        if ((termios->c_cflag & CSIZE) == CS7)
                smr_val |= 0x40;
        if (termios->c_cflag & PARENB)
                smr_val |= 0x20;
        if (termios->c_cflag & PARODD)
                smr_val |= 0x30;
        if (termios->c_cflag & CSTOPB)
                smr_val |= 0x08;

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

        sci_out(port, SCSMR, smr_val);

        if (t > 0) {
                if(t >= 256) {
                        sci_out(port, SCSMR, (sci_in(port, SCSMR) & ~3) | 1);
                        t >>= 2;
                } else {
                        sci_out(port, SCSMR, sci_in(port, SCSMR) & ~3);
                }
                sci_out(port, SCBRR, t);
                udelay((1000000+(baud-1)) / baud); /* Wait one bit interval */
        }

        if (likely(s->init_pins))
                s->init_pins(port, termios->c_cflag);

        sci_out(port, SCSCR, SCSCR_INIT(port));

        if ((termios->c_cflag & CREAD) != 0)
              sci_start_rx(port,0);
}

static const char *sci_type(struct uart_port *port)
{
        switch (port->type) {
                case PORT_SCI:  return "sci";
                case PORT_SCIF: return "scif";
                case PORT_IRDA: return "irda";
                case PORT_SCIFA:        return "scifa";
        }

        return NULL;
}

static void sci_release_port(struct uart_port *port)
{
        /* Nothing here yet .. */
}

static int sci_request_port(struct uart_port *port)
{
        /* Nothing here yet .. */
        return 0;
}

static void sci_config_port(struct uart_port *port, int flags)
{
        struct sci_port *s = &sci_ports[port->line];

        port->type = s->type;

        switch (port->type) {
        case PORT_SCI:
                s->init_pins = sci_init_pins_sci;
                break;
        case PORT_SCIF:
        case PORT_SCIFA:
                s->init_pins = sci_init_pins_scif;
                break;
        case PORT_IRDA:
                s->init_pins = sci_init_pins_irda;
                break;
        }

        if (port->flags & UPF_IOREMAP && !port->membase) {
#if defined(CONFIG_SUPERH64)
                port->mapbase = onchip_remap(SCIF_ADDR_SH5, 1024, "SCIF");
                port->membase = (void __iomem *)port->mapbase;
#else
                port->membase = ioremap_nocache(port->mapbase, 0x40);
#endif

                printk(KERN_ERR "sci: can't remap port#%d\n", port->line);
        }
}

static int sci_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        struct sci_port *s = &sci_ports[port->line];

        if (ser->irq != s->irqs[SCIx_TXI_IRQ] || ser->irq > nr_irqs)
                return -EINVAL;
        if (ser->baud_base < 2400)
                /* No paper tape reader for Mitch.. */
                return -EINVAL;

        return 0;
}

static struct uart_ops sci_uart_ops = {
        .tx_empty       = sci_tx_empty,
        .set_mctrl      = sci_set_mctrl,
        .get_mctrl      = sci_get_mctrl,
        .start_tx       = sci_start_tx,
        .stop_tx        = sci_stop_tx,
        .stop_rx        = sci_stop_rx,
        .enable_ms      = sci_enable_ms,
        .break_ctl      = sci_break_ctl,
        .startup        = sci_startup,
        .shutdown       = sci_shutdown,
        .set_termios    = sci_set_termios,
        .type           = sci_type,
        .release_port   = sci_release_port,
        .request_port   = sci_request_port,
        .config_port    = sci_config_port,
        .verify_port    = sci_verify_port,
};

static void __init sci_init_ports(void)
{
        static int first = 1;
        int i;

        if (!first)
                return;

        first = 0;

        for (i = 0; i < SCI_NPORTS; i++) {
                sci_ports[i].port.ops           = &sci_uart_ops;
                sci_ports[i].port.iotype        = UPIO_MEM;
                sci_ports[i].port.line          = i;
                sci_ports[i].port.fifosize      = 1;

#if defined(__H8300H__) || defined(__H8300S__)
#ifdef __H8300S__
                sci_ports[i].enable     = h8300_sci_enable;
                sci_ports[i].disable    = h8300_sci_disable;
#endif
                sci_ports[i].port.uartclk = CONFIG_CPU_CLOCK;
#elif defined(CONFIG_HAVE_CLK)
                /*
                 * XXX: We should use a proper SCI/SCIF clock
                 */
                {
                        struct clk *clk = clk_get(NULL, "module_clk");
                        sci_ports[i].port.uartclk = clk_get_rate(clk);
                        clk_put(clk);
                }
#else
#error "Need a valid uartclk"
#endif

                sci_ports[i].break_timer.data = (unsigned long)&sci_ports[i];
                sci_ports[i].break_timer.function = sci_break_timer;

                init_timer(&sci_ports[i].break_timer);
        }
}

int __init early_sci_setup(struct uart_port *port)
{
        if (unlikely(port->line > SCI_NPORTS))
                return -ENODEV;

        sci_init_ports();

        sci_ports[port->line].port.membase      = port->membase;
        sci_ports[port->line].port.mapbase      = port->mapbase;
        sci_ports[port->line].port.type         = port->type;

        return 0;
}

#ifdef CONFIG_SERIAL_SH_SCI_CONSOLE
/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 */
static void serial_console_write(struct console *co, const char *s,
                                 unsigned count)
{
        put_string(serial_console_port, s, count);
}

static int __init serial_console_setup(struct console *co, char *options)
{
        struct uart_port *port;
        int baud = 115200;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';
        int ret;

        /*
         * 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 >= SCI_NPORTS)
                co->index = 0;

        serial_console_port = &sci_ports[co->index];
        port = &serial_console_port->port;

        /*
         * Also need to check port->type, we don't actually have any
         * UPIO_PORT ports, but uart_report_port() handily misreports
         * it anyways if we don't have a port available by the time this is
         * called.
         */
        if (!port->type)
                return -ENODEV;
        if (!port->membase || !port->mapbase)
                return -ENODEV;

        port->type = serial_console_port->type;

#ifdef CONFIG_HAVE_CLK
        if (!serial_console_port->clk)
                serial_console_port->clk = clk_get(NULL, "module_clk");
#endif

        if (port->flags & UPF_IOREMAP)
                sci_config_port(port, 0);

        if (serial_console_port->enable)
                serial_console_port->enable(port);

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

        ret = uart_set_options(port, co, baud, parity, bits, flow);
#if defined(__H8300H__) || defined(__H8300S__)
        /* disable rx interrupt */
        if (ret == 0)
                sci_stop_rx(port);
#endif
        return ret;
}

static struct console serial_console = {
        .name           = "ttySC",
        .device         = uart_console_device,
        .write          = serial_console_write,
        .setup          = serial_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &sci_uart_driver,
};

static int __init sci_console_init(void)
{
        sci_init_ports();
        register_console(&serial_console);
        return 0;
}
console_initcall(sci_console_init);
#endif /* CONFIG_SERIAL_SH_SCI_CONSOLE */

#ifdef CONFIG_SH_KGDB_CONSOLE
/*
 * FIXME: Most of this can go away.. at the moment, we rely on
 * arch/sh/kernel/setup.c to do the command line parsing for kgdb, though
 * most of that can easily be done here instead.
 *
 * For the time being, just accept the values that were parsed earlier..
 */
static void __init kgdb_console_get_options(struct uart_port *port, int *baud,
                                            int *parity, int *bits)
{
        *baud = kgdb_baud;
        *parity = tolower(kgdb_parity);
        *bits = kgdb_bits - '0';
}

/*
 * The naming here is somewhat misleading, since kgdb_console_setup() takes
 * care of the early-on initialization for kgdb, regardless of whether we
 * actually use kgdb as a console or not.
 *
 * On the plus side, this lets us kill off the old kgdb_sci_setup() nonsense.
 */
int __init kgdb_console_setup(struct console *co, char *options)
{
        struct uart_port *port = &sci_ports[kgdb_portnum].port;
        int baud = 38400;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        if (co->index != kgdb_portnum)
                co->index = kgdb_portnum;

        kgdb_sci_port = &sci_ports[co->index];
        port = &kgdb_sci_port->port;

        /*
         * Also need to check port->type, we don't actually have any
         * UPIO_PORT ports, but uart_report_port() handily misreports
         * it anyways if we don't have a port available by the time this is
         * called.
         */
        if (!port->type)
                return -ENODEV;
        if (!port->membase || !port->mapbase)
                return -ENODEV;

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

        kgdb_getchar = kgdb_sci_getchar;
        kgdb_putchar = kgdb_sci_putchar;

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

static struct console kgdb_console = {
        .name           = "ttySC",
        .device         = uart_console_device,
        .write          = kgdb_console_write,
        .setup          = kgdb_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &sci_uart_driver,
};

/* Register the KGDB console so we get messages (d'oh!) */
static int __init kgdb_console_init(void)
{
        sci_init_ports();
        register_console(&kgdb_console);
        return 0;
}
console_initcall(kgdb_console_init);
#endif /* CONFIG_SH_KGDB_CONSOLE */

#if defined(CONFIG_SH_KGDB_CONSOLE)
#define SCI_CONSOLE     &kgdb_console
#elif defined(CONFIG_SERIAL_SH_SCI_CONSOLE)
#define SCI_CONSOLE     &serial_console
#else
#define SCI_CONSOLE     0
#endif

static char banner[] __initdata =
        KERN_INFO "SuperH SCI(F) driver initialized\n";

static struct uart_driver sci_uart_driver = {
        .owner          = THIS_MODULE,
        .driver_name    = "sci",
        .dev_name       = "ttySC",
        .major          = SCI_MAJOR,
        .minor          = SCI_MINOR_START,
        .nr             = SCI_NPORTS,
        .cons           = SCI_CONSOLE,
};

/*
 * Register a set of serial devices attached to a platform device.  The
 * list is terminated with a zero flags entry, which means we expect
 * all entries to have at least UPF_BOOT_AUTOCONF set. Platforms that need
 * remapping (such as sh64) should also set UPF_IOREMAP.
 */
static int __devinit sci_probe(struct platform_device *dev)
{
        struct plat_sci_port *p = dev->dev.platform_data;
        int i, ret = -EINVAL;

        for (i = 0; p && p->flags != 0; p++, i++) {
                struct sci_port *sciport = &sci_ports[i];

                /* Sanity check */
                if (unlikely(i == SCI_NPORTS)) {
                        dev_notice(&dev->dev, "Attempting to register port "
                                   "%d when only %d are available.\n",
                                   i+1, SCI_NPORTS);
                        dev_notice(&dev->dev, "Consider bumping "
                                   "CONFIG_SERIAL_SH_SCI_NR_UARTS!\n");
                        break;
                }

                sciport->port.mapbase   = p->mapbase;

                if (p->mapbase && !p->membase) {
                        if (p->flags & UPF_IOREMAP) {
                                p->membase = ioremap_nocache(p->mapbase, 0x40);
                                if (IS_ERR(p->membase)) {
                                        ret = PTR_ERR(p->membase);
                                        goto err_unreg;
                                }
                        } else {
                                /*
                                 * For the simple (and majority of) cases
                                 * where we don't need to do any remapping,
                                 * just cast the cookie directly.
                                 */
                                p->membase = (void __iomem *)p->mapbase;
                        }
                }

                sciport->port.membase   = p->membase;

                sciport->port.irq       = p->irqs[SCIx_TXI_IRQ];
                sciport->port.flags     = p->flags;
                sciport->port.dev       = &dev->dev;

                sciport->type           = sciport->port.type = p->type;

                memcpy(&sciport->irqs, &p->irqs, sizeof(p->irqs));

                uart_add_one_port(&sci_uart_driver, &sciport->port);
        }

#if defined(CONFIG_SH_KGDB) && !defined(CONFIG_SH_KGDB_CONSOLE)
        kgdb_sci_port   = &sci_ports[kgdb_portnum];
        kgdb_getchar    = kgdb_sci_getchar;
        kgdb_putchar    = kgdb_sci_putchar;
#endif

#if defined(CONFIG_CPU_FREQ) && defined(CONFIG_HAVE_CLK)
        cpufreq_register_notifier(&sci_nb, CPUFREQ_TRANSITION_NOTIFIER);
        dev_info(&dev->dev, "CPU frequency notifier registered\n");
#endif

#ifdef CONFIG_SH_STANDARD_BIOS
        sh_bios_gdb_detach();
#endif

        return 0;

err_unreg:
        for (i = i - 1; i >= 0; i--)
                uart_remove_one_port(&sci_uart_driver, &sci_ports[i].port);

        return ret;
}

static int __devexit sci_remove(struct platform_device *dev)
{
        int i;

        for (i = 0; i < SCI_NPORTS; i++)
                uart_remove_one_port(&sci_uart_driver, &sci_ports[i].port);

        return 0;
}

static int sci_suspend(struct platform_device *dev, pm_message_t state)
{
        int i;

        for (i = 0; i < SCI_NPORTS; i++) {
                struct sci_port *p = &sci_ports[i];

                if (p->type != PORT_UNKNOWN && p->port.dev == &dev->dev)
                        uart_suspend_port(&sci_uart_driver, &p->port);
        }

        return 0;
}

static int sci_resume(struct platform_device *dev)
{
        int i;

        for (i = 0; i < SCI_NPORTS; i++) {
                struct sci_port *p = &sci_ports[i];

                if (p->type != PORT_UNKNOWN && p->port.dev == &dev->dev)
                        uart_resume_port(&sci_uart_driver, &p->port);
        }

        return 0;
}

static struct platform_driver sci_driver = {
        .probe          = sci_probe,
        .remove         = __devexit_p(sci_remove),
        .suspend        = sci_suspend,
        .resume         = sci_resume,
        .driver         = {
                .name   = "sh-sci",
                .owner  = THIS_MODULE,
        },
};

static int __init sci_init(void)
{
        int ret;

        printk(banner);

        sci_init_ports();

        ret = uart_register_driver(&sci_uart_driver);
        if (likely(ret == 0)) {
                ret = platform_driver_register(&sci_driver);
                if (unlikely(ret))
                        uart_unregister_driver(&sci_uart_driver);
        }

        return ret;
}

static void __exit sci_exit(void)
{
        platform_driver_unregister(&sci_driver);
        uart_unregister_driver(&sci_uart_driver);
}

module_init(sci_init);
module_exit(sci_exit);

MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sh-sci");