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Commit e8770484 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: ftdi_sio: clean up SIO write support 



The original SIO devices require a control byte for every packet
written. Clean up the unnecessarily messy implementation of this.

Signed-off-by: default avatarJohan Hovold <jhovold@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent d3901a06

drivers/usb/serial/ftdi_sio.c

+13 −40
Original line number Diff line number Diff line
@@ -71,10 +71,6 @@ struct ftdi_private { 
				/* the last data state set - needed for doing

				 * a break

				 */

	int write_offset;       /* This is the offset in the usb data block to

				 * write the serial data - it varies between

				 * devices

				 */

	int flags;		/* some ASYNC_xxxx flags are supported */

	unsigned long last_dtr_rts;	/* saved modem control outputs */

	wait_queue_head_t delta_msr_wait; /* Used for TIOCMIWAIT */
@@ -1279,7 +1275,6 @@ static void ftdi_determine_type(struct usb_serial_port *port) 


	/* Assume it is not the original SIO device for now. */

	priv->baud_base = 48000000 / 2;

	priv->write_offset = 0;



	version = le16_to_cpu(udev->descriptor.bcdDevice);

	interfaces = udev->actconfig->desc.bNumInterfaces;
@@ -1321,7 +1316,6 @@ static void ftdi_determine_type(struct usb_serial_port *port) 
		/* Old device.  Assume it's the original SIO. */

		priv->chip_type = SIO;

		priv->baud_base = 12000000 / 16;

		priv->write_offset = 1;

	} else if (version < 0x400) {

		/* Assume it's an FT8U232AM (or FT8U245AM) */

		/* (It might be a BM because of the iSerialNumber bug,
@@ -1757,50 +1751,29 @@ static int ftdi_prepare_write_buffer(struct usb_serial_port *port, 
{

	struct ftdi_private *priv;

	unsigned char *buffer;

	int data_offset ;       /* will be 1 for the SIO and 0 otherwise */

	int transfer_size;

	int len;



	priv = usb_get_serial_port_data(port);



	data_offset = priv->write_offset;

	dbg("data_offset set to %d", data_offset);

	len = count;

	if (priv->chip_type == SIO && count != 0)

		len += ((count - 1) / (priv->max_packet_size - 1)) + 1;



	/* Determine total transfer size */

	transfer_size = count;

	if (data_offset > 0) {

		/* Original sio needs control bytes too... */

		transfer_size += (data_offset *

				((count + (priv->max_packet_size - 1 - data_offset)) /

				 (priv->max_packet_size - data_offset)));

	}



	buffer = kmalloc(transfer_size, GFP_ATOMIC);

	buffer = kmalloc(len, GFP_ATOMIC);

	if (!buffer) {

		dev_err(&port->dev, "%s - could not allocate buffer\n",

				__func__);

		return -ENOMEM;

	}



	/* Copy data */

	if (data_offset > 0) {

		/* Original sio requires control byte at start of

		   each packet. */

		int user_pktsz = priv->max_packet_size - data_offset;

		int todo = count;

		unsigned char *first_byte = buffer;

		const unsigned char *current_position = src;



		while (todo > 0) {

			if (user_pktsz > todo)

				user_pktsz = todo;

			/* Write the control byte at the front of the packet*/

			*first_byte = 1 | ((user_pktsz) << 2);

			/* Copy data for packet */

			memcpy(first_byte + data_offset,

				current_position, user_pktsz);

			first_byte += user_pktsz + data_offset;

			current_position += user_pktsz;

			todo -= user_pktsz;

	if (priv->chip_type == SIO) {

		int i, msg_len;



		for (i = 0; i < len; i += priv->max_packet_size) {

			msg_len = min_t(int, len - i, priv->max_packet_size) - 1;

			buffer[i] = (msg_len << 2) + 1;

			memcpy(&buffer[i + 1], src, msg_len);

			src += msg_len;

		}

	} else {

		memcpy(buffer, src, count);