jpt_driver.c

这是一个LINUX下多串口驱动程序

		info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE - 1);
		info->wbl[i & 3] = c;
		tbuf[i] = c;
	}
	

	spin_lock_irqsave(&info->lock, flags);
	nuart_write_buf(info->base, buf_pos, tbuf, wbl_pos + count);
	spin_unlock_irqrestore(&info->lock, flags);

	info->xmit_cnt -= count;

	info->twp += count;
	
	spin_lock_irqsave(&info->lock, flags);
	nuart_set_twp(info->base, &info->reg, info->twp);
	spin_unlock_irqrestore(&info->lock, flags);

	if(info->xmit_cnt < WAKEUP_CHARS)
	{
		set_bit(NUART_EVENT_TXLOW, &info->event);	
		schedule_work(&info->tqueue);
	}

	return;
}
static void nuart16_transmit_chars(struct nuart_struct *info)
{
	int count, i;
	int wbl_pos;
	int buf_pos;
	char  tbuf[256];
	int c;
	unsigned long flags = 0;

	count = 120 - ((info->twp - info->trp) & 0x7f);
	count = MIN(info->xmit_cnt, count);

	if(count <= 0)
		return;

	wbl_pos = info->twp & 3;
	buf_pos = info->twp & (~3);
	if(wbl_pos)
		memcpy(tbuf,info->wbl,wbl_pos);
	
	for(i = wbl_pos;i < count + wbl_pos; i++)
	{
		c = info->xmit_buf[info->xmit_tail++];
		info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE - 1);
		info->wbl[i & 3] = c;
		tbuf[i] = c;
	}
	

	spin_lock_irqsave(&info->lock, flags);
	nuart_write_buf(info->base, buf_pos, tbuf, wbl_pos + count);
	spin_unlock_irqrestore(&info->lock, flags);

	info->xmit_cnt -= count;

	info->twp += count;
	
	spin_lock_irqsave(&info->lock, flags);
	nuart_set_twp(info->base, &info->reg, info->twp);
	spin_unlock_irqrestore(&info->lock, flags);

	if(info->xmit_cnt < WAKEUP_CHARS)
	{
		set_bit(NUART_EVENT_TXLOW, &info->event);	
		schedule_work(&info->tqueue);
	}

	return;
}

static void nuart_timeout_port(struct nuart_struct * info)
{
	unsigned long	status, flags;

	spin_lock_irqsave(&info->lock, flags);
	status = nuart_get_stat(info->base);
	spin_unlock_irqrestore(&info->lock, flags);

	info->rwp = ((status & 0xff00) >> 8) & 0xff;
	info->trp = status & 0xff;

	if((status & (NUART_RI | NUART_DSR | NUART_DCD | NUART_CTS)) != 
		(info->reg.mpr & (NUART_RI | NUART_DSR | NUART_DCD | NUART_CTS)))
		nuart_check_modem_status(info, status);

	nuart_receive_chars(info, status);
	info->reg.mpr = status;

	if (info->xmit_cnt && !info->tty->stopped && !info->tty->hw_stopped)
		nuart_transmit_chars(info);
		
}
static void nuart_timeout_single(int board, struct nuart_hwconf *hwconf)
{
	struct nuart_struct *info;
	int i, n;

	n = board * NUART_PORTS_PER_BOARD;
	info = &nuvar_table[n];

	for (i = 0; i < hwconf->ports; i++, n++, info++) 
	{
		if(info->port != n)
			continue;
		if (info->flags & ASYNC_INITIALIZED)
			nuart_timeout_port(info);
	}
}

static void nuart_timeout(unsigned long ptr)
{
	int i;

	for (i = 0; i < NUART_BOARDS; i++) 
	{
		if (nuartcfg[i].board_type == -1)
			continue;

		nuart_timeout_single(i, &nuartcfg[i]);
	}

	nuart_timer.function = nuart_timeout;
	nuart_timer.data = (unsigned long)0;
	nuart_timer.expires = jiffies + 1;  /* 1ms */

	add_timer(&nuart_timer);
	return;
}

static int nuart_open(struct tty_struct *tty, struct file *filp)
{
	struct nuart_struct *info;
	int retval, line;
	unsigned long page;

	line = PORTNO(tty);
	if ((line < 0) || (line >= NUART_PORTS))
		return (-ENODEV);

	info = &nuvar_table[line];
	if (!info->base)
		return (-ENODEV);

	tty->driver_data = info;
	info->tty = tty;

	if (!nuvar_tmp_buf) {
		page = get_zeroed_page(GFP_KERNEL);
		if (!page)
			return (-ENOMEM);
		if (nuvar_tmp_buf)
			free_page(page);
		else
			nuvar_tmp_buf = (unsigned char *) page;
	}
	/*
	 * Start up serial port
	 */
	info->count++;
	retval = nuart_startup(info);
	if (retval)
		return (retval);

	return nuart_block_til_ready(tty, filp, info);
}

static int nuart_get_line(struct file * f, char * buf, ssize_t size, loff_t * off)
{
	int n, i;
	loff_t offset = *off;

	n = f->f_op->read(f, buf, size, &offset);

	if(n <= 0)
		return 0;

	for(i = 0; i < n ; i++)
	{
		if(buf[i] == 0xa)
			break;
	}

	buf[i] = 0;
	i++;
	*off += i;	

	return i;
}

static int nuart_atoi(char * s)
{
	int n = 0;
	char * p = s;

	while((*p == ' ') || (*p == '\t'))
		p ++;

	while((*p >= '0') && (*p <= '9'))
	{
		n *= 10;
		n += *p - '0';
		p ++;
	}
	return n;
} 

static void nuart_get_mode(struct nuart_struct * info)
{
	struct file * f;	
	char	buf[256];
	char	*s;
	mm_segment_t fs;
	loff_t offset = 0;

	if(info->type == NUART_BOARD_RS232)
	{
		info->mode = NUART_PORT_RS232;
		return;
	}

	f = filp_open("/etc/jpt.conf",O_RDWR, 0600);
	if(IS_ERR(f))
	{
		printk("WARNING : /etc/jpt.conf does not exist\n");
		info->mode = -1;
	}
	else
	{
		info->mode = -1;
		fs = get_fs();
		set_fs(KERNEL_DS);
		while(nuart_get_line(f, buf, sizeof(buf), &offset))
		{
			if(memcmp(buf, "ttyn", 4))
				continue;

			s = buf + 4;

			if(nuart_atoi(s) != info->port)
				continue;

			while((*s != ' ') && (*s != '\t'))
				s++;
		
			info->mode = nuart_atoi(s);
			break;
		}
		set_fs(fs);

		filp_close(f, NULL);
	}


	switch(info->type)
	{
	case NUART_BOARD_RS232:
		break;
	case NUART_BOARD_RS485:
		if((info->mode != NUART_PORT_RS485F) && (info->mode != NUART_PORT_RS485H))
		{
			printk("WARNING : set ttyn%d to default mode(rs_485 full)\n", info->port);
			info->mode = NUART_PORT_RS485F;
		}
		break;
	case NUART_BOARD_RS422_RS485:
		if((info->mode != NUART_PORT_RS422) && (info->mode != NUART_PORT_RS485F) && (info->mode != NUART_PORT_RS485H))
		{
			printk("WARNING : set ttyn%d to default mode(rs_485 full)\n", info->port);
			info->mode = NUART_PORT_RS485F;
		}
		break;
	case NUART_BOARD_RS232_RS422_RS485:
		if((info->mode != NUART_PORT_RS232) && (info->mode != NUART_PORT_RS422) && (info->mode != NUART_PORT_RS485F) && (info->mode != NUART_PORT_RS485H))
		{
			printk("WARNING : set ttyn%d to default mode(rs_232)\n", info->port);
			info->mode = NUART_PORT_RS232;
		}
		break;
	default:
		printk("WARNING : set ttyn%d to default mode(rs_232)\n", info->port);
		info->mode = NUART_PORT_RS232;
	}

	return;
}

static int nuart_startup(struct nuart_struct *info)
{
	unsigned long flags = 0;
	unsigned long page;

	page = get_zeroed_page(GFP_KERNEL);
	if (!page)
		return (-ENOMEM);

	spin_lock_irqsave(&info->lock, flags);
	if (info->flags & ASYNC_INITIALIZED) {
		free_page(page);
		spin_unlock_irqrestore(&info->lock, flags);
		return (0);
	}

	if (!info->base) 
	{
		if (info->tty)
			set_bit(TTY_IO_ERROR, &info->tty->flags);
		free_page(page);
		spin_unlock_irqrestore(&info->lock, flags);
		return (0);
	}
	if (info->xmit_buf)
		free_page(page);
	else
		info->xmit_buf = (unsigned char *) page;
	
	/* initialize the port */ 
	nuart_get_mode(info);	
	nuart_port_enable_and_init(info->base, &info->reg, info->mode);
	nuart_dtr(info->base, &info->reg, 1);
	nuart_rts(info->base, &info->reg, 1);

	info->lflag = (NUART_LFLAG_RDI | NUART_LFLAG_MSI | NUART_LFLAG_THRI | NUART_LFLAG_RLSI);

	if (info->tty)
		test_and_clear_bit(TTY_IO_ERROR, &info->tty->flags);

	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;

	spin_unlock_irqrestore(&info->lock, flags);
	/*
	 * and set the speed of the serial port
	 */
	nuart_change_speed(info, 0);

	info->flags |= ASYNC_INITIALIZED;
	return (0);
}

static int nuart_change_speed(struct nuart_struct *info, struct termios *old_termios)
{
	unsigned cflag, cval;
	int i;
	int ret = 0;
	unsigned long flags;

	unsigned long quot = 0;
	unsigned long pcr = 0;
	unsigned long pcr_mask = 0;

	if (!info->tty || !info->tty->termios)
		return ret;
	cflag = info->tty->termios->c_cflag;
	if (!(info->base))
		return ret;


#ifndef B921600
#define B921600 (B460800 +1)
#endif
	switch (cflag & (CBAUD | CBAUDEX)) 
	{
	case B921600:
		i = 20;
		break;
	case B460800:
		i = 19;
		break;
	case B230400:
		i = 18;
		break;
	case B115200:
		i = 17;
		break;
	case B57600:
		i = 16;
		break;
	case B38400:
		i = 15;
		break;
	case B19200:
		i = 14;
		break;
	case B9600:
		i = 13;
		break;
	case B4800:
		i = 12;
		break;
	case B2400:
		i = 11;
		break;
	case B1800:
		i = 10;
		break;
	case B1200:
		i = 9;
		break;
	case B600:
		i = 8;
		break;
	case B300:
		i = 7;
		break;
	case B200:
		i = 6;
		break;
	case B150:
		i = 5;
		break;
	case B134:
		i = 4;
		break;
	case B110:
		i = 3;
		break;
	case B75:
		i = 2;
		break;
	case B50:
		i = 1;
		break;
	default:
		i = 0;
		break;
	}

	if(i == 15)
	{
		if((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
			i = 16;
		if((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
			i = 17;
#ifdef ASYNC_SPD_SHI
		if((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
			i = 18;
#endif
#ifdef ASYNC_SPD_WARP
		if((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
			i = 19;
#endif
	}

	if (nuart_baud_table[i]) 
		quot = info->baud_base / nuart_baud_table[i];
	else 
		quot = 0;

	if(quot)
		quot --;

	/* byte size and parity */
	pcr = 0;
	cval = 9;
	if (cflag & CSTOPB)
	{
		pcr |= NUART_SBITS;
	}

	if (cflag & PARENB)
	{
		pcr |= NUART_PEN;
		if (!(cflag & PARODD))
			pcr |= NUART_P_EVEN;
		cval -= 1;
	}

	switch (cflag & CSIZE) 
	{
	case CS5:
		pcr |= cval  - 5;;
		break;
	case CS6:
		pcr |= cval  - 6;;
		break;
	case CS7:
		pcr |= cval  - 7;
		break;
	case CS8:
		pcr |= cval  - 8;
		break;
	default:
		break;		/* too keep GCC shut... */
	}

	if (cflag & CRTSCTS) 
	{
		if(!(info->reg.pcr & NUART_RTSC_FLOW))
		{
			info->flags |= ASYNC_CTS_FLOW;
			pcr_mask |= NUART_RTSC_MASK;
			pcr |= (NUART_OCTS | NUART_RTSC_FLOW);