sh-sci.c

/*
 * drivers/serial/sh-sci.c
 *
 * SuperH on-chip serial module support.  (SCI with no FIFO / with FIFO)
 *
 *  Copyright (C) 2002 - 2006  Paul Mundt
 *
 * 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).
 *
 * 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.
 */

#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>

#ifdef CONFIG_CPU_FREQ
#include <linux/notifier.h>
#include <linux/cpufreq.h>
#endif

#if defined(CONFIG_SUPERH) && !defined(CONFIG_SUPERH64)
#include <asm/clock.h>
#include <asm/sh_bios.h>
#include <asm/kgdb.h>
#endif

#include <asm/sci.h>

#if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#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_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_out(port, SCxTDR, c);
	sci_in(port, SCxSR);            /* Dummy read */
	sci_out(port, SCxSR, SCxSR_TDxE_CLEAR(port));

	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 && (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 = highhex(c);
			l = lowhex(c);
			put_char(port, h);
			put_char(port, l);
			checksum += h + l;
		}
		put_char(port, '#');
		put_char(port, highhex(checksum));
		put_char(port, lowhex(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)) < 0)
		cpu_relax();

        return c;
}

static inline void kgdb_sci_putchar(int c)
{
        put_char(kgdb_sci_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(SCI_ONLY) || defined(SCI_AND_SCIF) && \
    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

#ifdef SCI_ONLY
#define sci_init_pins_scif NULL
#endif

#if defined(SCIF_ONLY) || defined(SCI_AND_SCIF)
#if defined(CONFIG_CPU_SUBTYPE_SH7300) || defined(CONFIG_CPU_SUBTYPE_SH7710)
/* SH7300 doesn't use RTS/CTS */
static void sci_init_pins_scif(struct uart_port *port, unsigned int cflag)
{
	sci_out(port, SCFCR, 0);
}
#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);
}
#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 {
#ifdef CONFIG_CPU_SUBTYPE_SH7343
		/* Nothing */
#elif defined(CONFIG_CPU_SUBTYPE_SH7780)
		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)
static inline int scif_txroom(struct uart_port *port)
{
	return SCIF_TXROOM_MAX - (sci_in(port, SCTFDR) & 0x7f);
}

static inline int scif_rxroom(struct uart_port *port)
{
	return sci_in(port, SCRFDR) & 0x7f;
}
#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
#endif /* SCIF_ONLY || SCI_AND_SCIF */

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;
	}

#ifndef SCI_ONLY
	if (port->type == PORT_SCIF)
		count = scif_txroom(port);
	else
#endif
		count = sci_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 !defined(SCI_ONLY)
		if (port->type == PORT_SCIF) {
			sci_in(port, SCxSR); /* Dummy read */
			sci_out(port, SCxSR, SCxSR_TDxE_CLEAR(port));
		}
#endif

		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 pt_regs *regs)
{
	struct sci_port *sci_port = (struct sci_port *)port;
	struct tty_struct *tty = port->info->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 !defined(SCI_ONLY)
		if (port->type == PORT_SCIF)
			count = scif_rxroom(port);
		else
#endif
			count = sci_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, regs) || 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, regs)) {
					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->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->tty;
	struct sci_port *s = &sci_ports[port->line];

	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_SCIF && (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, struct pt_regs *regs)
{
	/* 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, regs);

	return IRQ_HANDLED;
}

static irqreturn_t sci_tx_interrupt(int irq, void *ptr, struct pt_regs *regs)
{
	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 pt_regs *regs)
{
	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->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, regs);
	}

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

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

	return IRQ_HANDLED;
}

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

	/* Handle BREAKs */
	sci_handle_breaks(port);

#ifdef CONFIG_SH_KGDB
	/* Break into the debugger if a break is detected */
	BREAKPOINT();
#endif

	sci_out(port, SCxSR, SCxSR_BREAK_CLEAR(port));

	return IRQ_HANDLED;
}

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

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

	/* Tx Interrupt */
        if ((ssr_status & 0x0020) && (scr_status & 0x0080))
                sci_tx_interrupt(irq, ptr, regs);
	/* Rx Interrupt */
        if ((ssr_status & 0x0002) && (scr_status & 0x0040))
                sci_rx_interrupt(irq, ptr, regs);
	/* Error Interrupt */
        if ((ssr_status & 0x0080) && (scr_status & 0x0400))
                sci_er_interrupt(irq, ptr, regs);
	/* Break Interrupt */
        if ((ssr_status & 0x0010) && (scr_status & 0x0200))
                sci_br_interrupt(irq, ptr, regs);

	return IRQ_HANDLED;
}

#ifdef CONFIG_CPU_FREQ
/*
 * 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("module_clk");
			port->uartclk = clk_get_rate(clk) * 16;
			clk_put(clk);
		}

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

	return NOTIFY_OK;
}

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

static int sci_request_irq(struct sci_port *port)
{
	int i;
	irqreturn_t (*handlers[4])(int irq, void *ptr, struct pt_regs *regs) = {
		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,
				SA_INTERRUPT, "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],
					SA_INTERRUPT, 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);

	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);
}

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

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

	switch (baud) {
		case 0:
			t = -1;
			break;
		default:
		{
#if defined(CONFIG_SUPERH) && !defined(CONFIG_SUPERH64)
			struct clk *clk = clk_get("module_clk");
			t = SCBRR_VALUE(baud, clk_get_rate(clk));
			clk_put(clk);
#else
			t = SCBRR_VALUE(baud);
#endif
		}
			break;
	}

	spin_lock_irqsave(&port->lock, flags);

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

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

#if !defined(SCI_ONLY)
	if (port->type == PORT_SCIF)
		sci_out(port, SCFCR, SCFCR_RFRST | SCFCR_TFRST);
#endif

	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);

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

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";
	}

	return 0;
}

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:
		s->init_pins = sci_init_pins_scif;
		break;
	case PORT_IRDA:
		s->init_pins = sci_init_pins_irda;
		break;
	}

#if defined(CONFIG_CPU_SUBTYPE_SH5_101) || defined(CONFIG_CPU_SUBTYPE_SH5_103)
	if (port->mapbase == 0)
		port->mapbase = onchip_remap(SCIF_ADDR_SH5, 1024, "SCIF");

	port->membase = (void __iomem *)port->mapbase;
#endif
}

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_SUPERH64)
		sci_ports[i].port.uartclk = current_cpu_data.module_clock * 16;
#else
		/*
		 * XXX: We should use a proper SCI/SCIF clock
		 */
		{
			struct clk *clk = clk_get("module_clk");
			sci_ports[i].port.uartclk = clk_get_rate(clk) * 16;
			clk_put(clk);
		}
#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;

	spin_lock_init(&port->lock);

	port->type = serial_console_port->type;

	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
/*
 * 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';

	spin_lock_init(&port->lock);

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

	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);
}
#endif /* CONFIG_SH_KGDB */

#ifdef CONFIG_SH_KGDB_CONSOLE
static struct console kgdb_console = {
        .name		= "ttySC",
        .write		= kgdb_console_write,
        .setup		= kgdb_console_setup,
        .flags		= CON_PRINTBUFFER | CON_ENABLED,
        .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;

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

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

		/*
		 * For the simple (and majority of) cases where we don't need
		 * to do any remapping, just cast the cookie directly.
		 */
		if (p->mapbase && !p->membase && !(p->flags & UPF_IOREMAP))
			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);
	}

#ifdef CONFIG_CPU_FREQ
	cpufreq_register_notifier(&sci_nb, CPUFREQ_TRANSITION_NOTIFIER);
	dev_info(&dev->dev, "sci: CPU frequency notifier registered\n");
#endif

#ifdef CONFIG_SH_STANDARD_BIOS
	sh_bios_gdb_detach();
#endif

	return 0;
}

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");