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USB: ftdi_sio: clean up SIO write support

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

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Johan Hovold 2010-05-05 23:45:01 +02:00 committed by Greg Kroah-Hartman
parent d3901a064c
commit e877048417
1 changed files with 12 additions and 39 deletions
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51
drivers/usb/serial/ftdi_sio.c
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@ -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;
if (priv->chip_type == SIO) {
int i, msg_len;
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;
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);