sh-sci.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,633 行 · 第 1/3 页

/*
 * drivers/serial/sh-sci.c
 *
 * SuperH on-chip serial module support.  (SCI with no FIFO / with FIFO)
 *
 *  Copyright (C) 2002, 2003  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.
 */

#define DEBUG
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.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/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/console.h>

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

#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/bitops.h>

#include <linux/generic_serial.h>

#ifdef CONFIG_SH_STANDARD_BIOS
#include <asm/sh_bios.h>
#endif

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

#include "sh-sci.h"

#ifdef CONFIG_SH_KGDB
#include <asm/kgdb.h>

static int kgdb_get_char(struct sci_port *port);
static void kgdb_put_char(struct sci_port *port, char c);
static void kgdb_handle_error(struct sci_port *port);
static struct sci_port *kgdb_sci_port;
#endif /* CONFIG_SH_KGDB */

#ifdef CONFIG_SERIAL_SH_SCI_CONSOLE
static struct sci_port *serial_console_port = 0;
#endif /* CONFIG_SERIAL_SH_SCI_CONSOLE */

/* Function prototypes */
static void sci_stop_tx(struct uart_port *port, unsigned int tty_stop);
static void sci_start_tx(struct uart_port *port, unsigned int tty_start);
static void sci_start_rx(struct uart_port *port, unsigned int tty_start);
static void sci_stop_rx(struct uart_port *port);
static int sci_request_irq(struct sci_port *port);
static void sci_free_irq(struct sci_port *port);

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

#if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)

static 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;

	local_irq_save(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));
	local_irq_restore(flags);

	return c;
}

/* Taken from sh-stub.c of GDB 4.18 */
static const char hexchars[] = "0123456789abcdef";

static __inline__ char highhex(int  x)
{
	return hexchars[(x >> 4) & 0xf];
}

static __inline__ char lowhex(int  x)
{
	return hexchars[x & 0xf];
}

#endif /* CONFIG_SH_STANDARD_BIOS || CONFIG_SH_KGDB */

/*
 * Send the packet in buffer.  The host gets one chance to read it.
 * This routine does not wait for a positive acknowledge.
 */

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

	local_irq_save(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));

	local_irq_restore(flags);
}

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

/* Is the SCI ready, ie is there a char waiting? */
static int kgdb_is_char_ready(struct sci_port *port)
{
        unsigned short status = sci_in(port, SCxSR);

        if (status & (SCxSR_ERRORS(port) | SCxSR_BRK(port)))
                kgdb_handle_error(port);

        return (status & SCxSR_RDxF(port));
}

/* Write a char */
static void kgdb_put_char(struct sci_port *port, char c)
{
        unsigned short status;

        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));
}

/* Get a char if there is one, else ret -1 */
static int kgdb_get_char(struct sci_port *port)
{
        int c;

        if (kgdb_is_char_ready(port) == 0)
                c = -1;
        else {
                c = sci_in(port, SCxRDR);
                sci_in(port, SCxSR);    /* Dummy read */
                sci_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
        }

        return c;
}

/* Called from kgdbstub.c to get a character, i.e. is blocking */
static int kgdb_sci_getchar(void)
{
        volatile int c;

        /* Keep trying to read a character, this could be neater */
        while ((c = kgdb_get_char(kgdb_sci_port)) < 0);

        return c;
}

/* Called from kgdbstub.c to put a character, just a wrapper */
static void kgdb_sci_putchar(int c)
{

        kgdb_put_char(kgdb_sci_port, c);
}

/* Clear any errors on the SCI */
static void kgdb_handle_error(struct sci_port *port)
{
        sci_out(port, SCxSR, SCxSR_ERROR_CLEAR(port));  /* Clear error flags */
}

/* Breakpoint if there's a break sent on the serial port */
static void kgdb_break_interrupt(int irq, void *ptr, struct pt_regs *regs)
{
        struct sci_port *port = ptr;
        unsigned short status = sci_in(port, SCxSR);

        if (status & SCxSR_BRK(port)) {

                /* Break into the debugger if a break is detected */
                BREAKPOINT();

                /* Clear */
                sci_out(port, SCxSR, SCxSR_BREAK_CLEAR(port));
        }
}

#endif /* CONFIG_SH_KGDB */

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

static void h8300_sci_enable(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;
	}
}
#endif

#if defined(SCI_ONLY) || defined(SCI_AND_SCIF)
#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
static void sci_init_pins_sci(struct uart_port *port, unsigned int cflag)
{
}
#endif
#endif

#if defined(SCIF_ONLY) || defined(SCI_AND_SCIF)
#if defined(CONFIG_CPU_SH3)
/* For SH7707, SH7709, SH7709A, SH7729, SH7300*/
static void sci_init_pins_scif(struct uart_port *port, unsigned int cflag)
{
	unsigned int fcr_val = 0;
#if !defined(CONFIG_CPU_SUBTYPE_SH7300) /* SH7300 doesn't use RTS/CTS */
	{
		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 {
		unsigned short data;

		/* 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);
	}
#endif
	sci_out(port, SCFCR, fcr_val);
}

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

/* 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 {
		ctrl_outw(0x0080, SCSPTR2); /* Set RTS = 1 */
	}
	sci_out(port, SCFCR, fcr_val);
}

#endif
#endif /* SCIF_ONLY || SCI_AND_SCIF */

/* ********************************************************************** *
 *                   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 long flags;
	unsigned short status;
	unsigned short ctrl;
	int count, txroom;

	status = sci_in(port, SCxSR);
	if (!(status & SCxSR_TDxE(port))) {
		local_irq_save(flags);
		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);
		local_irq_restore(flags);
		return;
	}

#if !defined(SCI_ONLY)
	if (port->type == PORT_SCIF) {
		txroom = SCIF_TXROOM_MAX - (sci_in(port, SCFDR)>>8);
	} else {
		txroom = (sci_in(port, SCxSR) & SCI_TDRE)?1:0;
	}
#else
	txroom = (sci_in(port, SCxSR) & SCI_TDRE)?1:0;
#endif

	count = txroom;

	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, 0);
	} else {
		local_irq_save(flags);
		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);
		local_irq_restore(flags);
	}
}

/* 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 tty_struct *tty = port->info->tty;
	int i, count, copied = 0;
	unsigned short status;

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

	while (1) {
#if !defined(SCI_ONLY)
		if (port->type == PORT_SCIF) {
			count = sci_in(port, SCFDR)&SCIF_RFDC_MASK ;
		} else {
			count = (sci_in(port, SCxSR)&SCxSR_RDxF(port))?1:0;
		}
#else
		count = (sci_in(port, SCxSR)&SCxSR_RDxF(port))?1:0;
#endif

		/* Don't copy more bytes than there is room for in the buffer */
		if (tty->flip.count + count > TTY_FLIPBUF_SIZE)
			count = TTY_FLIPBUF_SIZE - tty->flip.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(((struct sci_port *)port)->break_flag
			    || uart_handle_sysrq_char(port, c, regs)) {
				count = 0;
			} else {
			    tty->flip.char_buf_ptr[0] = c;
			    tty->flip.flag_buf_ptr[0] = 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 (((struct sci_port *)port)->break_flag) {
					if ((c == 0) &&
					    (status & SCxSR_FER(port))) {
						count--; i--;
						continue;
					}
					/* Nonzero => end-of-break */
					pr_debug("scif: debounce<%02x>\n", c);
					((struct sci_port *)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 */
				tty->flip.char_buf_ptr[i] = c;
				if (status&SCxSR_FER(port)) {