esp.c

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

	/*
	 * Set up the tty->alt_speed kludge
	 */
	if (info->tty) {
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
			info->tty->alt_speed = 57600;
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
			info->tty->alt_speed = 115200;
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
			info->tty->alt_speed = 230400;
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
			info->tty->alt_speed = 460800;
	}
	
	/*
	 * set the speed of the serial port
	 */
	change_speed(info);

	info->flags |= ASYNC_INITIALIZED;
	retval = 0;
out:	restore_flags(flags);
	return retval;
}

/*
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 */
static void shutdown(struct esp_struct * info)
{
	unsigned long	flags, f;

	if (!(info->flags & ASYNC_INITIALIZED))
		return;

#ifdef SERIAL_DEBUG_OPEN
	printk("Shutting down serial port %d (irq %d)....", info->line,
	       info->irq);
#endif
	
	save_flags(flags); cli(); /* Disable interrupts */

	/*
	 * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
	 * here so the queue might never be waken up
	 */
	wake_up_interruptible(&info->delta_msr_wait);
	wake_up_interruptible(&info->break_wait);

	/* stop a DMA transfer on the port being closed */
	   
	if (info->stat_flags & (ESP_STAT_DMA_RX | ESP_STAT_DMA_TX)) {
		f=claim_dma_lock();
		disable_dma(dma);
		clear_dma_ff(dma);
		release_dma_lock(f);
		
		dma_bytes = 0;
	}
	
	/*
	 * Free the IRQ
	 */
	free_irq(info->irq, info);

	if (dma_buffer) {
		struct esp_struct *current_port = ports;

		while (current_port) {
			if ((current_port != info) &&
			    (current_port->flags & ASYNC_INITIALIZED))
				break;

			current_port = current_port->next_port;
		}

		if (!current_port) {
			free_dma(dma);
			free_pages((unsigned long)dma_buffer,
				   get_order(DMA_BUFFER_SZ));
			dma_buffer = 0;
		}		
	}

	if (info->xmit_buf) {
		free_page((unsigned long) info->xmit_buf);
		info->xmit_buf = 0;
	}

	info->IER = 0;
	serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
	serial_out(info, UART_ESI_CMD2, 0x00);

	if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
		info->MCR &= ~(UART_MCR_DTR|UART_MCR_RTS);

	info->MCR &= ~UART_MCR_OUT2;
	serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
	serial_out(info, UART_ESI_CMD2, UART_MCR);
	serial_out(info, UART_ESI_CMD2, info->MCR);

	if (info->tty)
		set_bit(TTY_IO_ERROR, &info->tty->flags);
	
	info->flags &= ~ASYNC_INITIALIZED;
	restore_flags(flags);
}

/*
 * This routine is called to set the UART divisor registers to match
 * the specified baud rate for a serial port.
 */
static void change_speed(struct esp_struct *info)
{
	unsigned short port;
	int	quot = 0;
	unsigned cflag,cval;
	int	baud, bits;
	unsigned char flow1 = 0, flow2 = 0;
	unsigned long flags;

	if (!info->tty || !info->tty->termios)
		return;
	cflag = info->tty->termios->c_cflag;
	port = info->port;
	
	/* byte size and parity */
	switch (cflag & CSIZE) {
	      case CS5: cval = 0x00; bits = 7; break;
	      case CS6: cval = 0x01; bits = 8; break;
	      case CS7: cval = 0x02; bits = 9; break;
	      case CS8: cval = 0x03; bits = 10; break;
	      default:  cval = 0x00; bits = 7; break;
	}
	if (cflag & CSTOPB) {
		cval |= 0x04;
		bits++;
	}
	if (cflag & PARENB) {
		cval |= UART_LCR_PARITY;
		bits++;
	}
	if (!(cflag & PARODD))
		cval |= UART_LCR_EPAR;
#ifdef CMSPAR
	if (cflag & CMSPAR)
		cval |= UART_LCR_SPAR;
#endif

	baud = tty_get_baud_rate(info->tty);
	if (baud == 38400 &&
	    ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST))
		quot = info->custom_divisor;
	else {
		if (baud == 134)
			/* Special case since 134 is really 134.5 */
			quot = (2*BASE_BAUD / 269);
		else if (baud)
			quot = BASE_BAUD / baud;
	}
	/* If the quotient is ever zero, default to 9600 bps */
	if (!quot)
		quot = BASE_BAUD / 9600;
	
	info->timeout = ((1024 * HZ * bits * quot) / BASE_BAUD) + (HZ / 50);

	/* CTS flow control flag and modem status interrupts */
	/* info->IER &= ~UART_IER_MSI; */
	if (cflag & CRTSCTS) {
		info->flags |= ASYNC_CTS_FLOW;
		/* info->IER |= UART_IER_MSI; */
		flow1 = 0x04;
		flow2 = 0x10;
	} else
		info->flags &= ~ASYNC_CTS_FLOW;
	if (cflag & CLOCAL)
		info->flags &= ~ASYNC_CHECK_CD;
	else {
		info->flags |= ASYNC_CHECK_CD;
		/* info->IER |= UART_IER_MSI; */
	}

	/*
	 * Set up parity check flag
	 */
#define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))

	info->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
	if (I_INPCK(info->tty))
		info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
	if (I_BRKINT(info->tty) || I_PARMRK(info->tty))
		info->read_status_mask |= UART_LSR_BI;
	
	info->ignore_status_mask = 0;
#if 0
	/* This should be safe, but for some broken bits of hardware... */
	if (I_IGNPAR(info->tty)) {
		info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
		info->read_status_mask |= UART_LSR_PE | UART_LSR_FE;
	}
#endif
	if (I_IGNBRK(info->tty)) {
		info->ignore_status_mask |= UART_LSR_BI;
		info->read_status_mask |= UART_LSR_BI;
		/*
		 * If we're ignore parity and break indicators, ignore 
		 * overruns too.  (For real raw support).
		 */
		if (I_IGNPAR(info->tty)) {
			info->ignore_status_mask |= UART_LSR_OE | \
				UART_LSR_PE | UART_LSR_FE;
			info->read_status_mask |= UART_LSR_OE | \
				UART_LSR_PE | UART_LSR_FE;
		}
	}

	if (I_IXOFF(info->tty))
		flow1 |= 0x81;

	save_flags(flags); cli();
	/* set baud */
	serial_out(info, UART_ESI_CMD1, ESI_SET_BAUD);
	serial_out(info, UART_ESI_CMD2, quot >> 8);
	serial_out(info, UART_ESI_CMD2, quot & 0xff);

	/* set data bits, parity, etc. */
	serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
	serial_out(info, UART_ESI_CMD2, UART_LCR);
	serial_out(info, UART_ESI_CMD2, cval);

	/* Enable flow control */
	serial_out(info, UART_ESI_CMD1, ESI_SET_FLOW_CNTL);
	serial_out(info, UART_ESI_CMD2, flow1);
	serial_out(info, UART_ESI_CMD2, flow2);

	/* set flow control characters (XON/XOFF only) */
	if (I_IXOFF(info->tty)) {
		serial_out(info, UART_ESI_CMD1, ESI_SET_FLOW_CHARS);
		serial_out(info, UART_ESI_CMD2, START_CHAR(info->tty));
		serial_out(info, UART_ESI_CMD2, STOP_CHAR(info->tty));
		serial_out(info, UART_ESI_CMD2, 0x10);
		serial_out(info, UART_ESI_CMD2, 0x21);
		switch (cflag & CSIZE) {
			case CS5:
				serial_out(info, UART_ESI_CMD2, 0x1f);
				break;
			case CS6:
				serial_out(info, UART_ESI_CMD2, 0x3f);
				break;
			case CS7:
			case CS8:
				serial_out(info, UART_ESI_CMD2, 0x7f);
				break;
			default:
				serial_out(info, UART_ESI_CMD2, 0xff);
				break;
		}
	}

	/* Set high/low water */
	serial_out(info, UART_ESI_CMD1, ESI_SET_FLOW_LVL);
	serial_out(info, UART_ESI_CMD2, info->config.flow_off >> 8);
	serial_out(info, UART_ESI_CMD2, info->config.flow_off);
	serial_out(info, UART_ESI_CMD2, info->config.flow_on >> 8);
	serial_out(info, UART_ESI_CMD2, info->config.flow_on);

	restore_flags(flags);
}

static void rs_put_char(struct tty_struct *tty, unsigned char ch)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
	unsigned long flags;

	if (serial_paranoia_check(info, tty->device, "rs_put_char"))
		return;

	if (!tty || !info->xmit_buf)
		return;

	save_flags(flags); cli();
	if (info->xmit_cnt >= ESP_XMIT_SIZE - 1) {
		restore_flags(flags);
		return;
	}

	info->xmit_buf[info->xmit_head++] = ch;
	info->xmit_head &= ESP_XMIT_SIZE-1;
	info->xmit_cnt++;
	restore_flags(flags);
}

static void rs_flush_chars(struct tty_struct *tty)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
	unsigned long flags;
				
	if (serial_paranoia_check(info, tty->device, "rs_flush_chars"))
		return;

	if (info->xmit_cnt <= 0 || tty->stopped || !info->xmit_buf)
		return;

	save_flags(flags); cli();
	if (!(info->IER & UART_IER_THRI)) {
		info->IER |= UART_IER_THRI;
		serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
		serial_out(info, UART_ESI_CMD2, info->IER);
	}
	restore_flags(flags);
}

static int rs_write(struct tty_struct * tty, int from_user,
		    const unsigned char *buf, int count)
{
	int	c, t, ret = 0;
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
	unsigned long flags;

	if (serial_paranoia_check(info, tty->device, "rs_write"))
		return 0;

	if (!tty || !info->xmit_buf || !tmp_buf)
		return 0;
	    
	if (from_user)
		down(&tmp_buf_sem);

	while (1) {
		/* Thanks to R. Wolff for suggesting how to do this with */
		/* interrupts enabled */

		c = count;
		t = ESP_XMIT_SIZE - info->xmit_cnt - 1;
		
		if (t < c)
			c = t;

		t = ESP_XMIT_SIZE - info->xmit_head;
		
		if (t < c)
			c = t;

		if (c <= 0)
			break;

		if (from_user) {
			c -= copy_from_user(tmp_buf, buf, c);

			if (!c) {
				if (!ret)
					ret = -EFAULT;
				break;
			}

			memcpy(info->xmit_buf + info->xmit_head, tmp_buf, c);
		} else
			memcpy(info->xmit_buf + info->xmit_head, buf, c);

		info->xmit_head = (info->xmit_head + c) & (ESP_XMIT_SIZE-1);
		info->xmit_cnt += c;
		buf += c;
		count -= c;
		ret += c;
	}

	if (from_user)
		up(&tmp_buf_sem);
	
	save_flags(flags); cli();

	if (info->xmit_cnt && !tty->stopped && !(info->IER & UART_IER_THRI)) {
		info->IER |= UART_IER_THRI;
		serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
		serial_out(info, UART_ESI_CMD2, info->IER);
	}

	restore_flags(flags);
	return ret;
}

static int rs_write_room(struct tty_struct *tty)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
	int	ret;
				
	if (serial_paranoia_check(info, tty->device, "rs_write_room"))
		return 0;
	ret = ESP_XMIT_SIZE - info->xmit_cnt - 1;
	if (ret < 0)
		ret = 0;
	return ret;
}

static int rs_chars_in_buffer(struct tty_struct *tty)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
				
	if (serial_paranoia_check(info, tty->device, "rs_chars_in_buffer"))
		return 0;
	return info->xmit_cnt;
}

static void rs_flush_buffer(struct tty_struct *tty)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
				
	if (serial_paranoia_check(info, tty->device, "rs_flush_buffer"))
		return;
	cli();
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	sti();
	wake_up_interruptible(&tty->write_wait);
	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
	    tty->ldisc.write_wakeup)
		(tty->ldisc.write_wakeup)(tty);
}

/*
 * ------------------------------------------------------------
 * rs_throttle()
 * 
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void rs_throttle(struct tty_struct * tty)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
#ifdef SERIAL_DEBUG_THROTTLE
	char	buf[64];
	
	printk("throttle %s: %d....\n", tty_name(tty, buf),
	       tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_throttle"))
		return;
	
	cli();
	info->IER &= ~UART_IER_RDI;
	serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
	serial_out(info, UART_ESI_CMD2, info->IER);
	serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
	serial_out(info, UART_ESI_CMD2, 0x00);
	sti();
}

static void rs_unthrottle(struct tty_struct * tty)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
#ifdef SERIAL_DEBUG_THROTTLE
	char	buf[64];
	
	printk("unthrottle %s: %d....\n", tty_name(tty, buf),
	       tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_unthrottle"))
		return;
	
	cli();
	info->IER |= UART_IER_RDI;
	serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
	serial_out(info, UART_ESI_CMD2, info->IER);
	serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
	serial_out(info, UART_ESI_CMD2, info->config.rx_timeout);
	sti();
}

/*
 * ------------------------------------------------------------
 * rs_ioctl() and friends
 * ------------------------------------------------------------
 */

static int get_serial_info(struct esp_struct * info,
			   struct serial_struct * retinfo)
{
	struct serial_struct tmp;
  
	if (!retinfo)
		return -EFAULT;
	memset(&tmp, 0, sizeof(tmp));
	tmp.type = PORT_16550A;
	tmp.line = info->line;
	tmp.port = info->port;
	tmp.irq = info->irq;