ftdi_sio.c

NP-Convert,usb4口转换器的驱动开发示例.面向Linux.

	/* 3. Convert baudrate to device-specific divisor */

	if (!baud) baud = 9600;	
	switch(priv->chip_type) {
	case SIO: /* SIO chip */
		chip_name = "SIO";
		switch(baud) {
		case 300: div_value = ftdi_sio_b300; break;
		case 600: div_value = ftdi_sio_b600; break;
		case 1200: div_value = ftdi_sio_b1200; break;
		case 2400: div_value = ftdi_sio_b2400; break;
		case 4800: div_value = ftdi_sio_b4800; break;
		case 9600: div_value = ftdi_sio_b9600; break;
		case 19200: div_value = ftdi_sio_b19200; break;
		case 38400: div_value = ftdi_sio_b38400; break;
		case 57600: div_value = ftdi_sio_b57600;  break;
		case 115200: div_value = ftdi_sio_b115200; break;
		} /* baud */
		if (div_value == 0) {
  			dbg("%s - Baudrate (%d) requested is not supported", __FUNCTION__,  baud);
			div_value = ftdi_sio_b9600;
			div_okay = 0;
		}
		break;
	case FT8U232AM: /* 8U232AM chip */
		chip_name = "FT8U232AM";
		if (baud <= 3000000) {
			div_value = ftdi_232am_baud_to_divisor(baud);
		} else {
	                dbg("%s - Baud rate too high!", __FUNCTION__);
			div_value = ftdi_232am_baud_to_divisor(9600);
			div_okay = 0;
		}
		break;
	case FT232BM: /* FT232BM chip */
	case FT2232C: /* FT2232C chip */
	case FT232R: /* FT232R chip */
		if (priv->chip_type == FT232R) {
			chip_name = "FT232R";
		} else if (priv->chip_type == FT2232C) {
			chip_name = "FT2232C";
		} else {
			chip_name = "FT232BM";
		}
		if (baud <= 3000000) {
			div_value = ftdi_232bm_baud_to_divisor(baud);
		} else {
	                dbg("%s - Baud rate too high!", __FUNCTION__);
			div_value = ftdi_232bm_baud_to_divisor(9600);
			div_okay = 0;
		}
		break;
	} /* priv->chip_type */

	if (div_okay) {
		dbg("%s - Baud rate set to %d (divisor 0x%lX) on chip %s",
			__FUNCTION__, baud, (unsigned long)div_value, chip_name);
	}

	return(div_value);
}


static int get_serial_info(struct usb_serial_port * port, struct serial_struct * retinfo)
{
	struct ftdi_private * priv = (struct ftdi_private*) port->private;
	struct serial_struct tmp;

	if (!retinfo)
		return -EFAULT;
	memset(&tmp, 0, sizeof(tmp));
	tmp.flags = priv->flags;
	tmp.baud_base = priv->baud_base;
	tmp.custom_divisor = priv->custom_divisor;
	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
		return -EFAULT;
	return 0;
} /* get_serial_info */


static int set_serial_info(struct usb_serial_port * port, struct serial_struct * newinfo)
{ /* set_serial_info */
	struct ftdi_private * priv = (struct ftdi_private *) port->private;
	struct serial_struct new_serial;
	struct ftdi_private old_priv;

	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
		return -EFAULT;
	old_priv = * priv;

	/* Do error checking and permission checking */

	if (!capable(CAP_SYS_ADMIN)) {
		if (((new_serial.flags & ~ASYNC_USR_MASK) !=
		     (priv->flags & ~ASYNC_USR_MASK)))
			return -EPERM;
		priv->flags = ((priv->flags & ~ASYNC_USR_MASK) |
			       (new_serial.flags & ASYNC_USR_MASK));
		priv->custom_divisor = new_serial.custom_divisor;
		goto check_and_exit;
	}

	if ((new_serial.baud_base != priv->baud_base) &&
	    (new_serial.baud_base < 9600))
		return -EINVAL;

	/* Make the changes - these are privileged changes! */

	priv->flags = ((priv->flags & ~ASYNC_FLAGS) |
	               (new_serial.flags & ASYNC_FLAGS));	
	priv->custom_divisor = new_serial.custom_divisor;

	port->tty->low_latency = (priv->flags & ASYNC_LOW_LATENCY) ? 1 : 0;

check_and_exit:
	if ((old_priv.flags & ASYNC_SPD_MASK) !=
	     (priv->flags & ASYNC_SPD_MASK)) {
		if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
			port->tty->alt_speed = 57600;
		else if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
			port->tty->alt_speed = 115200;
		else if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
			port->tty->alt_speed = 230400;
		else if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
			port->tty->alt_speed = 460800;
		else
			port->tty->alt_speed = 0;
	}
	if (((old_priv.flags & ASYNC_SPD_MASK) !=
	     (priv->flags & ASYNC_SPD_MASK)) ||
	    (((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST) &&
	     (old_priv.custom_divisor != priv->custom_divisor))) {
		change_speed(port);
	}
	
	return (0);

} /* set_serial_info */

/*
 * ***************************************************************************
 * FTDI driver specific functions
 * ***************************************************************************
 */

/* Common startup subroutine */
/* Called from ftdi_SIO_startup, etc. */
static int ftdi_common_startup (struct usb_serial *serial)
{
	struct usb_serial_port *port = &serial->port[0];
	struct ftdi_private *priv;
	int i ;
	struct urb *urb; 
	
	dbg("%s",__FUNCTION__);

	priv = kmalloc(sizeof(struct ftdi_private), GFP_KERNEL);
	if (!priv){
		err("%s- kmalloc(%Zd) failed.", __FUNCTION__, sizeof(struct ftdi_private));
		return -ENOMEM;
	}
	memset(priv, 0, sizeof(*priv));
	
        init_waitqueue_head(&priv->delta_msr_wait);
	/* This will push the characters through immediately rather
	   than queue a task to deliver them */
	priv->flags = ASYNC_LOW_LATENCY;

	/* Increase the size of read buffers */
	if (port->bulk_in_buffer) {
		kfree (port->bulk_in_buffer);
	}
	port->bulk_in_buffer = kmalloc (BUFSZ, GFP_KERNEL);
	if (!port->bulk_in_buffer) {
		kfree (priv);
		return -ENOMEM;
	}
	if (port->read_urb) {
		port->read_urb->transfer_buffer = port->bulk_in_buffer;
		port->read_urb->transfer_buffer_length = BUFSZ;
	}

	/* Free port's existing write urb and transfer buffer. */
	if (port->write_urb) {
		usb_free_urb (port->write_urb);
		port->write_urb = NULL;
	}
	if (port->bulk_out_buffer) {
		kfree (port->bulk_out_buffer);
		port->bulk_out_buffer = NULL;
	}

	/* create our write urb pool and transfer buffers */ 
	spin_lock_init (&priv->write_urb_pool_lock);
	for (i = 0; i < NUM_URBS; ++i) {
		urb = usb_alloc_urb(0);
		priv->write_urb_pool[i] = urb;
		if (urb == NULL) {
			err("Unable to create new urb in urb pool");
			break;
		}

		urb->transfer_buffer = kmalloc (URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
		if (!urb->transfer_buffer) {
			err("%s - out of memory for urb buffers.", 
			    __FUNCTION__);
			continue;
		}
	}

	/* Need at least one write urb in the pool */
	if (i == 0) {
		kfree (priv);
		return -ENOMEM;
	}

	port->private = priv;
	
	return (0);
}


/* Startup for the SIO chip */
/* Called from usbserial:serial_probe */
static int ftdi_SIO_startup (struct usb_serial *serial)
{
	struct ftdi_private *priv;
	int err;

	dbg("%s",__FUNCTION__);

	err = ftdi_common_startup(serial);
	if (err){
		return (err);
	}

	priv = serial->port->private;
	priv->chip_type = SIO;
	priv->baud_base = 12000000 / 16;
	priv->write_offset = 1;
	
	return (0);
}

/* Startup for the 8U232AM chip */
/* Called from usbserial:serial_probe */
static int ftdi_8U232AM_startup (struct usb_serial *serial)
{ /* ftdi_8U232AM_startup */
	struct ftdi_private *priv;
	int err;

	dbg("%s",__FUNCTION__);
	err = ftdi_common_startup(serial);
	if (err){
		return (err);
	}

	priv = serial->port->private;
	priv->chip_type = FT8U232AM;
	priv->baud_base = 48000000 / 2; /* Would be / 16, but FTDI supports 0.125, 0.25 and 0.5 divisor fractions! */
	
	return (0);
} /* ftdi_8U232AM_startup */

/* Startup for the FT232BM chip */
/* Called from usbserial:serial_probe */
static int ftdi_FT232BM_startup (struct usb_serial *serial)
{ /* ftdi_FT232BM_startup */
	struct ftdi_private *priv;
	int err;

	dbg("%s",__FUNCTION__);
	err = ftdi_common_startup(serial);
	if (err){
		return (err);
	}

	priv = serial->port->private;
	priv->chip_type = FT232BM;
	priv->baud_base = 48000000 / 2; /* Would be / 16, but FT232BM supports multiple of 0.125 divisor fractions! */
	
	return (0);
} /* ftdi_FT232BM_startup */

/* Startup for the FT2232C chip */
/* Called from usbserial:serial_probe */
static int ftdi_FT2232C_startup (struct usb_serial *serial)
{ /* ftdi_FT2232C_startup */
	struct ftdi_private *priv;
	int err;
	int inter;

	dbg("%s",__FUNCTION__);
	err = ftdi_common_startup(serial);
	if (err){
		return (err);
	}

	priv = serial->port->private;
	priv->chip_type = FT2232C;
	inter = serial->interface->altsetting->bInterfaceNumber;

	if(inter) {
		priv->interface = INTERFACE_B;
	}
	else  {
		priv->interface = INTERFACE_A;
	}
	priv->baud_base = 48000000 / 2; /* Would be / 16, but FT232BM supports multiple of 0.125 divisor fractions! */
	
	return (0);
} /* ftdi_FT2232C_startup */

/* Startup for the FT232R chip */
/* Called from usbserial:serial_probe */
static int ftdi_FT232R_startup (struct usb_serial *serial)
{ /* ftdi_FT232R_startup */
	struct ftdi_private *priv;
	int err;

	dbg("%s",__FUNCTION__);
	err = ftdi_common_startup(serial);
	if (err){
		return (err);
	}

	priv = serial->port->private;
	priv->chip_type = FT232R;
	priv->baud_base = 48000000 / 2; /* Would be / 16, but FT232BM supports multiple of 0.125 divisor fractions! */
	
	return (0);
} /* ftdi_FT232R_startup */

/* Startup for the USB-UIRT device, which requires hardwired baudrate (38400 gets mapped to 312500) */
/* Called from usbserial:serial_probe */
static int ftdi_USB_UIRT_startup (struct usb_serial *serial)
{ /* ftdi_USB_UIRT_startup */
	struct ftdi_private *priv;
	int err;

	dbg("%s",__FUNCTION__);
	err = ftdi_8U232AM_startup(serial);
	if (err){
		return (err);
	}

	priv = serial->port->private;
	priv->flags |= ASYNC_SPD_CUST;
	priv->custom_divisor = 77;
	priv->force_baud = B38400;
	
	return (0);
} /* ftdi_USB_UIRT_startup */

/* Startup for the HE-TIRA1 device, which requires hardwired