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linux/drivers/usb/serial/aircable.c

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/*
* AIRcable USB Bluetooth Dongle Driver.
*
* Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com)
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation.
*
* The device works as an standard CDC device, it has 2 interfaces, the first
* one is for firmware access and the second is the serial one.
* The protocol is very simply, there are two posibilities reading or writing.
* When writing the first urb must have a Header that starts with 0x20 0x29 the
* next two bytes must say how much data will be sended.
* When reading the process is almost equal except that the header starts with
* 0x00 0x20.
*
* The device simply need some stuff to understand data comming from the usb
* buffer: The First and Second byte is used for a Header, the Third and Fourth
* tells the device the amount of information the package holds.
* Packages are 60 bytes long Header Stuff.
* When writing to the device the first two bytes of the header are 0x20 0x29
* When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange
* situation, when too much data arrives to the device because it sends the data
* but with out the header. I will use a simply hack to override this situation,
* if there is data coming that does not contain any header, then that is data
* that must go directly to the tty, as there is no documentation about if there
* is any other control code, I will simply check for the first
* one.
*
* The driver registers himself with the USB-serial core and the USB Core. I had
* to implement a probe function agains USB-serial, because other way, the
* driver was attaching himself to both interfaces. I have tryed with different
* configurations of usb_serial_driver with out exit, only the probe function
* could handle this correctly.
*
* I have taken some info from a Greg Kroah-Hartman article:
* http://www.linuxjournal.com/article/6573
* And from Linux Device Driver Kit CD, which is a great work, the authors taken
* the work to recompile lots of information an knowladge in drivers development
* and made it all avaible inside a cd.
* URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/
*
*/
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/circ_buf.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
static int debug;
/* Vendor and Product ID */
#define AIRCABLE_VID 0x16CA
#define AIRCABLE_USB_PID 0x1502
/* write buffer size defines */
#define AIRCABLE_BUF_SIZE 2048
/* Protocol Stuff */
#define HCI_HEADER_LENGTH 0x4
#define TX_HEADER_0 0x20
#define TX_HEADER_1 0x29
#define RX_HEADER_0 0x00
#define RX_HEADER_1 0x20
#define MAX_HCI_FRAMESIZE 60
#define HCI_COMPLETE_FRAME 64
/* rx_flags */
#define THROTTLED 0x01
#define ACTUALLY_THROTTLED 0x02
/*
* Version Information
*/
#define DRIVER_VERSION "v1.0b2"
#define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>"
#define DRIVER_DESC "AIRcable USB Driver"
/* ID table that will be registered with USB core */
static struct usb_device_id id_table [] = {
{ USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) },
{ },
};
MODULE_DEVICE_TABLE(usb, id_table);
/* Internal Structure */
struct aircable_private {
spinlock_t rx_lock; /* spinlock for the receive lines */
struct circ_buf *tx_buf; /* write buffer */
struct circ_buf *rx_buf; /* read buffer */
int rx_flags; /* for throttilng */
struct work_struct rx_work; /* work cue for the receiving line */
struct usb_serial_port *port; /* USB port with which associated */
};
/* Private methods */
/* Circular Buffer Methods, code from ti_usb_3410_5052 used */
/*
* serial_buf_clear
*
* Clear out all data in the circular buffer.
*/
static void serial_buf_clear(struct circ_buf *cb)
{
cb->head = cb->tail = 0;
}
/*
* serial_buf_alloc
*
* Allocate a circular buffer and all associated memory.
*/
static struct circ_buf *serial_buf_alloc(void)
{
struct circ_buf *cb;
cb = kmalloc(sizeof(struct circ_buf), GFP_KERNEL);
if (cb == NULL)
return NULL;
cb->buf = kmalloc(AIRCABLE_BUF_SIZE, GFP_KERNEL);
if (cb->buf == NULL) {
kfree(cb);
return NULL;
}
serial_buf_clear(cb);
return cb;
}
/*
* serial_buf_free
*
* Free the buffer and all associated memory.
*/
static void serial_buf_free(struct circ_buf *cb)
{
kfree(cb->buf);
kfree(cb);
}
/*
* serial_buf_data_avail
*
* Return the number of bytes of data available in the circular
* buffer.
*/
static int serial_buf_data_avail(struct circ_buf *cb)
{
return CIRC_CNT(cb->head,cb->tail,AIRCABLE_BUF_SIZE);
}
/*
* serial_buf_put
*
* Copy data data from a user buffer and put it into the circular buffer.
* Restrict to the amount of space available.
*
* Return the number of bytes copied.
*/
static int serial_buf_put(struct circ_buf *cb, const char *buf, int count)
{
int c, ret = 0;
while (1) {
c = CIRC_SPACE_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
if (count < c)
c = count;
if (c <= 0)
break;
memcpy(cb->buf + cb->head, buf, c);
cb->head = (cb->head + c) & (AIRCABLE_BUF_SIZE-1);
buf += c;
count -= c;
ret= c;
}
return ret;
}
/*
* serial_buf_get
*
* Get data from the circular buffer and copy to the given buffer.
* Restrict to the amount of data available.
*
* Return the number of bytes copied.
*/
static int serial_buf_get(struct circ_buf *cb, char *buf, int count)
{
int c, ret = 0;
while (1) {
c = CIRC_CNT_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
if (count < c)
c = count;
if (c <= 0)
break;
memcpy(buf, cb->buf + cb->tail, c);
cb->tail = (cb->tail + c) & (AIRCABLE_BUF_SIZE-1);
buf += c;
count -= c;
ret= c;
}
return ret;
}
/* End of circula buffer methods */
static void aircable_send(struct usb_serial_port *port)
{
int count, result;
struct aircable_private *priv = usb_get_serial_port_data(port);
unsigned char* buf;
__le16 *dbuf;
dbg("%s - port %d", __func__, port->number);
if (port->write_urb_busy)
return;
count = min(serial_buf_data_avail(priv->tx_buf), MAX_HCI_FRAMESIZE);
if (count == 0)
return;
buf = kzalloc(count + HCI_HEADER_LENGTH, GFP_ATOMIC);
if (!buf) {
err("%s- kzalloc(%d) failed.", __func__,
count + HCI_HEADER_LENGTH);
return;
}
buf[0] = TX_HEADER_0;
buf[1] = TX_HEADER_1;
dbuf = (__le16 *)&buf[2];
*dbuf = cpu_to_le16((u16)count);
serial_buf_get(priv->tx_buf,buf + HCI_HEADER_LENGTH, MAX_HCI_FRAMESIZE);
memcpy(port->write_urb->transfer_buffer, buf,
count + HCI_HEADER_LENGTH);
kfree(buf);
port->write_urb_busy = 1;
usb_serial_debug_data(debug, &port->dev, __func__,
count + HCI_HEADER_LENGTH,
port->write_urb->transfer_buffer);
port->write_urb->transfer_buffer_length = count + HCI_HEADER_LENGTH;
port->write_urb->dev = port->serial->dev;
result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
if (result) {
dev_err(&port->dev,
"%s - failed submitting write urb, error %d\n",
__func__, result);
port->write_urb_busy = 0;
}
schedule_work(&port->work);
}
static void aircable_read(struct work_struct *work)
{
struct aircable_private *priv =
container_of(work, struct aircable_private, rx_work);
struct usb_serial_port *port = priv->port;
struct tty_struct *tty;
unsigned char *data;
int count;
if (priv->rx_flags & THROTTLED){
if (priv->rx_flags & ACTUALLY_THROTTLED)
schedule_work(&priv->rx_work);
return;
}
/* By now I will flush data to the tty in packages of no more than
* 64 bytes, to ensure I do not get throttled.
* Ask USB mailing list for better aproach.
*/
tty = port->tty;
if (!tty) {
schedule_work(&priv->rx_work);
err("%s - No tty available", __func__);
return ;
}
count = min(64, serial_buf_data_avail(priv->rx_buf));
if (count <= 0)
return; //We have finished sending everything.
tty_prepare_flip_string(tty, &data, count);
if (!data){
err("%s- kzalloc(%d) failed.", __func__, count);
return;
}
serial_buf_get(priv->rx_buf, data, count);
tty_flip_buffer_push(tty);
if (serial_buf_data_avail(priv->rx_buf))
schedule_work(&priv->rx_work);
return;
}
/* End of private methods */
static int aircable_probe(struct usb_serial *serial,
const struct usb_device_id *id)
{
struct usb_host_interface *iface_desc = serial->interface->cur_altsetting;
struct usb_endpoint_descriptor *endpoint;
int num_bulk_out=0;
int i;
for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
endpoint = &iface_desc->endpoint[i].desc;
if (usb_endpoint_is_bulk_out(endpoint)) {
dbg("found bulk out on endpoint %d", i);
++num_bulk_out;
}
}
if (num_bulk_out == 0) {
dbg("Invalid interface, discarding");
return -ENODEV;
}
return 0;
}
static int aircable_attach (struct usb_serial *serial)
{
struct usb_serial_port *port = serial->port[0];
struct aircable_private *priv;
priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL);
if (!priv){
err("%s- kmalloc(%Zd) failed.", __func__,
sizeof(struct aircable_private));
return -ENOMEM;
}
/* Allocation of Circular Buffers */
priv->tx_buf = serial_buf_alloc();
if (priv->tx_buf == NULL) {
kfree(priv);
return -ENOMEM;
}
priv->rx_buf = serial_buf_alloc();
if (priv->rx_buf == NULL) {
kfree(priv->tx_buf);
kfree(priv);
return -ENOMEM;
}
priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
priv->port = port;
INIT_WORK(&priv->rx_work, aircable_read);
usb_set_serial_port_data(serial->port[0], priv);
return 0;
}
static void aircable_shutdown(struct usb_serial *serial)
{
struct usb_serial_port *port = serial->port[0];
struct aircable_private *priv = usb_get_serial_port_data(port);
dbg("%s", __func__);
if (priv) {
serial_buf_free(priv->tx_buf);
serial_buf_free(priv->rx_buf);
usb_set_serial_port_data(port, NULL);
kfree(priv);
}
}
static int aircable_write_room(struct usb_serial_port *port)
{
struct aircable_private *priv = usb_get_serial_port_data(port);
return serial_buf_data_avail(priv->tx_buf);
}
static int aircable_write(struct usb_serial_port *port,
const unsigned char *source, int count)
{
struct aircable_private *priv = usb_get_serial_port_data(port);
int temp;
dbg("%s - port %d, %d bytes", __func__, port->number, count);
usb_serial_debug_data(debug, &port->dev, __func__, count, source);
if (!count){
dbg("%s - write request of 0 bytes", __func__);
return count;
}
temp = serial_buf_put(priv->tx_buf, source, count);
aircable_send(port);
if (count > AIRCABLE_BUF_SIZE)
count = AIRCABLE_BUF_SIZE;
return count;
}
static void aircable_write_bulk_callback(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
int status = urb->status;
int result;
dbg("%s - urb status: %d", __func__ , status);
/* This has been taken from cypress_m8.c cypress_write_int_callback */
switch (status) {
case 0:
/* success */
break;
case -ECONNRESET:
case -ENOENT:
case -ESHUTDOWN:
/* this urb is terminated, clean up */
dbg("%s - urb shutting down with status: %d",
__func__, status);
port->write_urb_busy = 0;
return;
default:
/* error in the urb, so we have to resubmit it */
dbg("%s - Overflow in write", __func__);
dbg("%s - nonzero write bulk status received: %d",
__func__, status);
port->write_urb->transfer_buffer_length = 1;
port->write_urb->dev = port->serial->dev;
result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
if (result)
dev_err(&urb->dev->dev,
"%s - failed resubmitting write urb, error %d\n",
__func__, result);
else
return;
}
port->write_urb_busy = 0;
aircable_send(port);
}
static void aircable_read_bulk_callback(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
struct aircable_private *priv = usb_get_serial_port_data(port);
struct tty_struct *tty;
unsigned long no_packages, remaining, package_length, i;
int result, shift = 0;
unsigned char *temp;
int status = urb->status;
dbg("%s - port %d", __func__, port->number);
if (status) {
dbg("%s - urb status = %d", __func__, status);
if (!port->open_count) {
dbg("%s - port is closed, exiting.", __func__);
return;
}
if (status == -EPROTO) {
dbg("%s - caught -EPROTO, resubmitting the urb",
__func__);
usb_fill_bulk_urb(port->read_urb, port->serial->dev,
usb_rcvbulkpipe(port->serial->dev,
port->bulk_in_endpointAddress),
port->read_urb->transfer_buffer,
port->read_urb->transfer_buffer_length,
aircable_read_bulk_callback, port);
result = usb_submit_urb(urb, GFP_ATOMIC);
if (result)
dev_err(&urb->dev->dev,
"%s - failed resubmitting read urb, error %d\n",
__func__, result);
return;
}
dbg("%s - unable to handle the error, exiting.", __func__);
return;
}
usb_serial_debug_data(debug, &port->dev, __func__,
urb->actual_length,urb->transfer_buffer);
tty = port->tty;
if (tty && urb->actual_length) {
if (urb->actual_length <= 2) {
/* This is an incomplete package */
serial_buf_put(priv->rx_buf, urb->transfer_buffer,
urb->actual_length);
} else {
temp = urb->transfer_buffer;
if (temp[0] == RX_HEADER_0)
shift = HCI_HEADER_LENGTH;
remaining = urb->actual_length;
no_packages = urb->actual_length / (HCI_COMPLETE_FRAME);
if (urb->actual_length % HCI_COMPLETE_FRAME != 0)
no_packages+=1;
for (i = 0; i < no_packages ;i++) {
if (remaining > (HCI_COMPLETE_FRAME))
package_length = HCI_COMPLETE_FRAME;
else
package_length = remaining;
remaining -= package_length;
serial_buf_put(priv->rx_buf,
urb->transfer_buffer + shift +
(HCI_COMPLETE_FRAME) * (i),
package_length - shift);
}
}
aircable_read(&priv->rx_work);
}
/* Schedule the next read _if_ we are still open */
if (port->open_count) {
usb_fill_bulk_urb(port->read_urb, port->serial->dev,
usb_rcvbulkpipe(port->serial->dev,
port->bulk_in_endpointAddress),
port->read_urb->transfer_buffer,
port->read_urb->transfer_buffer_length,
aircable_read_bulk_callback, port);
result = usb_submit_urb(urb, GFP_ATOMIC);
if (result)
dev_err(&urb->dev->dev,
"%s - failed resubmitting read urb, error %d\n",
__func__, result);
}
return;
}
/* Based on ftdi_sio.c throttle */
static void aircable_throttle(struct usb_serial_port *port)
{
struct aircable_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
dbg("%s - port %d", __func__, port->number);
spin_lock_irqsave(&priv->rx_lock, flags);
priv->rx_flags |= THROTTLED;
spin_unlock_irqrestore(&priv->rx_lock, flags);
}
/* Based on ftdi_sio.c unthrottle */
static void aircable_unthrottle(struct usb_serial_port *port)
{
struct aircable_private *priv = usb_get_serial_port_data(port);
int actually_throttled;
unsigned long flags;
dbg("%s - port %d", __func__, port->number);
spin_lock_irqsave(&priv->rx_lock, flags);
actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
spin_unlock_irqrestore(&priv->rx_lock, flags);
if (actually_throttled)
schedule_work(&priv->rx_work);
}
static struct usb_driver aircable_driver = {
.name = "aircable",
.probe = usb_serial_probe,
.disconnect = usb_serial_disconnect,
.id_table = id_table,
.no_dynamic_id = 1,
};
static struct usb_serial_driver aircable_device = {
.driver = {
.owner = THIS_MODULE,
.name = "aircable",
},
.usb_driver = &aircable_driver,
.id_table = id_table,
.num_ports = 1,
.attach = aircable_attach,
.probe = aircable_probe,
.shutdown = aircable_shutdown,
.write = aircable_write,
.write_room = aircable_write_room,
.write_bulk_callback = aircable_write_bulk_callback,
.read_bulk_callback = aircable_read_bulk_callback,
.throttle = aircable_throttle,
.unthrottle = aircable_unthrottle,
};
static int __init aircable_init (void)
{
int retval;
retval = usb_serial_register(&aircable_device);
if (retval)
goto failed_serial_register;
retval = usb_register(&aircable_driver);
if (retval)
goto failed_usb_register;
return 0;
failed_serial_register:
usb_serial_deregister(&aircable_device);
failed_usb_register:
return retval;
}
static void __exit aircable_exit (void)
{
usb_deregister(&aircable_driver);
usb_serial_deregister(&aircable_device);
}
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL");
module_init(aircable_init);
module_exit(aircable_exit);
module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
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