duart_serial.c

powerpc内核mpc8241linux系统下char驱动程序

/*
 *  linux/drivers/char/serial.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Extensively rewritten by Theodore Ts'o, 8/16/92 -- 9/14/92.  Now
 *  much more extensible to support other serial cards based on the
 *  16450/16550A UART's.  Added support for the AST FourPort and the
 *  Accent Async board.  
 *
 *  set_serial_info fixed to set the flags, custom divisor, and uart
 * 	type fields.  Fix suggested by Michael K. Johnson 12/12/92.
 *
 *  11/95: TIOCMIWAIT, TIOCGICOUNT by Angelo Haritsis <[e-mail]>
 *
 *  03/96: Modularised by Angelo Haritsis <[e-mail]>
 *
 *  rs_set_termios fixed to look also for changes of the input
 *      flags INPCK, BRKINT, PARMRK, IGNPAR and IGNBRK.
 *                                            Bernd Anh鋟pl 05/17/96.
 *
 *  1/97:  Extended dumb serial ports are a config option now.  
 *         Saves 4k.   Michael A. Griffith <[e-mail]>
 * 
 *  8/97: Fix bug in rs_set_termios with RTS
 *        Stanislav V. Voronyi <[e-mail]>
 *
 *  3/98: Change the IRQ detection, use of probe_irq_o*(),
 *	  supress TIOCSERGWILD and TIOCSERSWILD
 *	  Etienne Lorrain <[e-mail]>
 *
 *  4/98: Added changes to support the ARM architecture proposed by
 * 	  Russell King
 *
 * This module exports the following rs232 io functions:
 *
 *	int rs_init(void);
 */

/*
 * Serial driver configuration section.  Here are the various options:
 *
 * CONFIG_HUB6
 *		Enables support for the venerable Bell Technologies
 *		HUB6 card.
 *
 * CONFIG_SERIAL_MANY_PORTS
 * 		Enables support for ports beyond the standard, stupid
 * 		COM 1/2/3/4.
 *
 * CONFIG_SERIAL_MULTIPORT
 * 		Enables support for special multiport board support.
 *
 * CONFIG_SERIAL_SHARE_IRQ
 * 		Enables support for multiple serial ports on one IRQ
 *
 * CONFIG_SERIAL_DETECT_IRQ
 *		Enable the autodetection of IRQ on standart ports
 *
 * SERIAL_PARANOIA_CHECK
 * 		Check the magic number for the async_structure where
 * 		ever possible.
 */

#undef SERIAL_PARANOIA_CHECK
#define CONFIG_SERIAL_NOPAUSE_IO
#define SERIAL_DO_RESTART

#if 0
/* Normally these defines are controlled by the autoconf.h */

#define CONFIG_SERIAL_MANY_PORTS
#define CONFIG_SERIAL_SHARE_IRQ
#define CONFIG_SERIAL_DETECT_IRQ
#define CONFIG_SERIAL_MULTIPORT
#define CONFIG_HUB6
#endif

/* Sanity checks */

#ifdef CONFIG_SERIAL_MULTIPORT
#ifndef CONFIG_SERIAL_SHARE_IRQ
#define CONFIG_SERIAL_SHARE_IRQ
#endif
#endif

#ifdef CONFIG_HUB6
#ifndef CONFIG_SERIAL_MANY_PORTS
#define CONFIG_SERIAL_MANY_PORTS
#endif
#ifndef CONFIG_SERIAL_SHARE_IRQ
#define CONFIG_SERIAL_SHARE_IRQ
#endif
#endif

/* Set of debugging defines */

#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW
#undef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
/*ebony*/
#define RS_STROBE_TIME (0*HZ)

#define RS_ISR_PASS_LIMIT 256

#define IRQ_T(info) ((info->flags & ASYNC_SHARE_IRQ) ? SA_SHIRQ : SA_INTERRUPT)

#define SERIAL_INLINE
  
#if defined(MODULE) && defined(SERIAL_DEBUG_MCOUNT)
#define DBG_CNT(s) printk("(%s): [%x] refc=%d, serc=%d, ttyc=%d -> %s\n", \
 kdevname(tty->device), (info->flags), serial_refcount,info->count,tty->count,s)
#else
#define DBG_CNT(s)
#endif


#define CONFIG_ADDR                 0xfec00000
#define CONFIG_DATA                 0xfee00000
#define BAUD_CLKIN                  (GetFreq()*1000*1000) /* 100MHz or 66MHz */

/*
 * End of serial driver configuration section.
 */

#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/serial_reg.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/malloc.h>
#include <linux/init.h>
#include <linux/delay.h>
#ifdef CONFIG_SERIAL_CONSOLE
#include <linux/console.h>
#endif

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


#ifdef SERIAL_INLINE
#define _INLINE_ inline
#endif
	
static char *serial_name = "Serial driver";
static char *serial_version = "4.27";

static DECLARE_TASK_QUEUE(tq_serial);

static struct tty_driver serial_driver, callout_driver;
static int serial_refcount;

/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256

/*
 * IRQ_timeout		- How long the timeout should be for each IRQ
 * 				should be after the IRQ has been active.
 */

static struct async_struct *IRQ_ports[NR_IRQS];
#ifdef CONFIG_SERIAL_MULTIPORT
static struct rs_multiport_struct rs_multiport[NR_IRQS];
#endif
static int IRQ_timeout[NR_IRQS];
#ifdef CONFIG_SERIAL_CONSOLE
static struct console sercons;
#endif

static unsigned detect_uart_irq (struct serial_state * state);
static void autoconfig(struct serial_state * info);
static void change_speed(struct async_struct *info, struct termios *old);
static void rs_wait_until_sent(struct tty_struct *tty, int timeout);

/*
 * Here we define the default xmit fifo size used for each type of
 * UART
 */
static struct serial_uart_config uart_config[] = {
	{ "unknown", 1, 0 }, 
	{ "8250", 1, 0 }, 
	{ "16450", 1, 0 }, 
	{ "16550", 1, 0 }, 
	{ "16550A", 16, UART_CLEAR_FIFO | UART_USE_FIFO }, 
	{ "cirrus", 1, 0 }, 
	{ "ST16650", 1, UART_CLEAR_FIFO | UART_STARTECH }, 
	{ "ST16650V2", 32, UART_CLEAR_FIFO | UART_USE_FIFO |
		  UART_STARTECH }, 
	{ "TI16750", 64, UART_CLEAR_FIFO | UART_USE_FIFO},
	{ 0, 0}
};

static struct serial_state rs_table[] = {
	SERIAL_PORT_DFNS	/* Defined in serial.h */
};

#define NR_PORTS	(sizeof(rs_table)/sizeof(struct serial_state))

static struct tty_struct *serial_table[NR_PORTS];
static struct termios *serial_termios[NR_PORTS];
static struct termios *serial_termios_locked[NR_PORTS];

#ifndef MIN
#define MIN(a,b)	((a) < (b) ? (a) : (b))
#endif


/********************* Read PCI Configuration, ebony*********/   

unsigned int ReadPCIConfig(int Devnum, int Reg)
{
        unsigned int *pInt;
        unsigned int Lval;

        pInt = (unsigned int *) CONFIG_ADDR;
        *pInt = ( Reg<<24 ) | (Devnum<<19) | 0x80; /* Reversed endian */
        pInt = (unsigned int *) CONFIG_DATA;
        Lval = *pInt;
        return Lval;
}


/*   GetFreq(), to get the memory clock for divisor --ebony */
int GetFreq()
{
  unsigned int pll;
  int freq,val_pll;
  pll=ReadPCIConfig(0,0xe2);
  val_pll=(pll&0x0000ff00)>>8;
  switch ( val_pll )
  {
    case 0x40:  freq=33;  break;
    case 0x20:  freq=66;  break;
    case 0x60:  freq=66;  break;
    case 0x70:  freq=66;  break;
    case 0xa0:  freq=66;  break;
    case 0xb0:  freq=66;  break;
    case 0xc0:  freq=83;  break;
    case 0x80:  freq=100; break;
 }

  return freq;
}









/*
 * tmp_buf is used as a temporary buffer by serial_write.  We need to
 * lock it in case the copy_from_user blocks while swapping in a page,
 * and some other program tries to do a serial write at the same time.
 * Since the lock will only come under contention when the system is
 * swapping and available memory is low, it makes sense to share one
 * buffer across all the serial ports, since it significantly saves
 * memory if large numbers of serial ports are open.
 */
static unsigned char *tmp_buf;
static struct semaphore tmp_buf_sem = MUTEX;

static inline int serial_paranoia_check(struct async_struct *info,
					kdev_t device, const char *routine)
{
#ifdef SERIAL_PARANOIA_CHECK
	static const char *badmagic =
		"Warning: bad magic number for serial struct (%s) in %s\n";
	static const char *badinfo =
		"Warning: null async_struct for (%s) in %s\n";

	if (!info) {
		printk(badinfo, kdevname(device), routine);
		return 1;
	}
	if (info->magic != SERIAL_MAGIC) {
		printk(badmagic, kdevname(device), routine);
		return 1;
	}
#endif
	return 0;
}

static inline unsigned int serial_in(struct async_struct *info, int offset)
{
#ifdef CONFIG_HUB6
    if (info->hub6) {
	eumb_outb(info->hub6 - 1 + offset, info->port);
	return eumb_inb(info->port+1);
    } else
#endif
	return eumb_inb(info->port + offset);
}

static inline unsigned int serial_inp(struct async_struct *info, int offset)
{
#ifdef CONFIG_HUB6
    if (info->hub6) {
	eumb_outb(info->hub6 - 1 + offset, info->port);
	return inb_p(info->port+1);
    } else
#endif
#ifdef CONFIG_SERIAL_NOPAUSE_IO
	return eumb_inb(info->port + offset);
#else
	return inb_p(info->port + offset);
#endif
}

static inline void serial_out(struct async_struct *info, int offset, int value)
{
#ifdef CONFIG_HUB6
    if (info->hub6) {
	eumb_outb(info->hub6 - 1 + offset, info->port);
	eumb_outb(value, info->port+1);
    } else
#endif
	eumb_outb(value, info->port+offset);
}

static inline void serial_outp(struct async_struct *info, int offset,
			       int value)
{
#ifdef CONFIG_HUB6
    if (info->hub6) {
	eumb_outb(info->hub6 - 1 + offset, info->port);
	outb_p(value, info->port+1);
    } else
#endif
#ifdef CONFIG_SERIAL_NOPAUSE_IO
	eumb_outb(value, info->port+offset);
#else
    	outb_p(value, info->port+offset);
#endif
}

/*
 * ------------------------------------------------------------
 * rs_stop() and rs_start()
 *
 * This routines are called before setting or resetting tty->stopped.
 * They enable or disable transmitter interrupts, as necessary.
 * ------------------------------------------------------------
 */
static void rs_stop(struct tty_struct *tty)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;

	if (serial_paranoia_check(info, tty->device, "rs_stop"))
		return;
	
	save_flags(flags); cli();
	if (info->IER & UART_IER_THRI) {
		info->IER &= ~UART_IER_THRI;
		serial_out(info, UART_IER, info->IER);
	}
	restore_flags(flags);
}

static void rs_start(struct tty_struct *tty)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;
	
	if (serial_paranoia_check(info, tty->device, "rs_start"))
		return;
	
	save_flags(flags); cli();
	if (info->xmit_cnt && info->xmit_buf && !(info->IER & UART_IER_THRI)) {
		info->IER |= UART_IER_THRI;
		serial_out(info, UART_IER, info->IER);
	}
	restore_flags(flags);
}

/*
 * ----------------------------------------------------------------------
 *
 * Here starts the interrupt handling routines.  All of the following
 * subroutines are declared as inline and are folded into
 * rs_interrupt().  They were separated out for readability's sake.
 *
 * Note: rs_interrupt() is a "fast" interrupt, which means that it
 * runs with interrupts turned off.  People who may want to modify
 * rs_interrupt() should try to keep the interrupt handler as fast as
 * possible.  After you are done making modifications, it is not a bad
 * idea to do:
 * 
 * gcc -S -DKERNEL -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer serial.c
 *
 * and look at the resulting assemble code in serial.s.
 *
 * 				- Ted Ts'o ([e-mail]), 7-Mar-93
 * -----------------------------------------------------------------------
 */

/*
 * This routine is used by the interrupt handler to schedule
 * processing in the software interrupt portion of the driver.
 */
static _INLINE_ void rs_sched_event(struct async_struct *info,
				  int event)
{
	info->event |= 1 << event;
	queue_task(&info->tqueue, &tq_serial);
	mark_bh(SERIAL_BH);
}

static _INLINE_ void receive_chars(struct async_struct *info,
				 int *status)
{
	struct tty_struct *tty = info->tty;
	unsigned char ch;
	int ignored = 0;
	struct	async_icount *icount;

	icount = &info->state->icount;
	do {
		ch = serial_inp(info, UART_RX);
		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
			break;
		*tty->flip.char_buf_ptr = ch;
		icount->rx++;
		
#ifdef SERIAL_DEBUG_INTR
		printk("DR%02x:%02x...", ch, *status);
#endif
		*tty->flip.flag_buf_ptr = 0;
		if (*status & (UART_LSR_BI | UART_LSR_PE |
			       UART_LSR_FE | UART_LSR_OE)) {
			/*
			 * For statistics only
			 */
			if (*status & UART_LSR_BI) {
				*status &= ~(UART_LSR_FE | UART_LSR_PE);
				icount->brk++;
			} else if (*status & UART_LSR_PE)
				icount->parity++;
			else if (*status & UART_LSR_FE)
				icount->frame++;
			if (*status & UART_LSR_OE)
				icount->overrun++;

			/*
			 * Now check to see if character should be
			 * ignored, and mask off conditions which
			 * should be ignored.
			 */
			if (*status & info->ignore_status_mask) {
				if (++ignored > 100)
					break;
				goto ignore_char;
			}
			*status &= info->read_status_mask;
		
			if (*status & (UART_LSR_BI)) {
#ifdef SERIAL_DEBUG_INTR
				printk("handling break....");
#endif
				*tty->flip.flag_buf_ptr = TTY_BREAK;
				if (info->flags & ASYNC_SAK)
					do_SAK(tty);
			} else if (*status & UART_LSR_PE)
				*tty->flip.flag_buf_ptr = TTY_PARITY;
			else if (*status & UART_LSR_FE)
				*tty->flip.flag_buf_ptr = TTY_FRAME;
			if (*status & UART_LSR_OE) {
				/*
				 * Overrun is special, since it's
				 * reported immediately, and doesn't
				 * affect the current character
				 */
				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
					tty->flip.count++;