linux/drivers/usb/serial/generic.c

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/*
* USB Serial Converter Generic functions
*
* Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.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.
*
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/sysrq.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/uaccess.h>
#include <linux/kfifo.h>
#include <linux/serial.h>
static int debug;
#ifdef CONFIG_USB_SERIAL_GENERIC
static int generic_probe(struct usb_interface *interface,
const struct usb_device_id *id);
static __u16 vendor = 0x05f9;
static __u16 product = 0xffff;
module_param(vendor, ushort, 0);
MODULE_PARM_DESC(vendor, "User specified USB idVendor");
module_param(product, ushort, 0);
MODULE_PARM_DESC(product, "User specified USB idProduct");
static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
/* we want to look at all devices, as the vendor/product id can change
* depending on the command line argument */
static const struct usb_device_id generic_serial_ids[] = {
{.driver_info = 42},
{}
};
static struct usb_driver generic_driver = {
.name = "usbserial_generic",
.probe = generic_probe,
.disconnect = usb_serial_disconnect,
.id_table = generic_serial_ids,
.no_dynamic_id = 1,
};
/* All of the device info needed for the Generic Serial Converter */
struct usb_serial_driver usb_serial_generic_device = {
.driver = {
.owner = THIS_MODULE,
.name = "generic",
},
.id_table = generic_device_ids,
.usb_driver = &generic_driver,
.num_ports = 1,
.disconnect = usb_serial_generic_disconnect,
.release = usb_serial_generic_release,
.throttle = usb_serial_generic_throttle,
.unthrottle = usb_serial_generic_unthrottle,
.resume = usb_serial_generic_resume,
};
static int generic_probe(struct usb_interface *interface,
const struct usb_device_id *id)
{
const struct usb_device_id *id_pattern;
id_pattern = usb_match_id(interface, generic_device_ids);
if (id_pattern != NULL)
return usb_serial_probe(interface, id);
return -ENODEV;
}
#endif
int usb_serial_generic_register(int _debug)
{
int retval = 0;
debug = _debug;
#ifdef CONFIG_USB_SERIAL_GENERIC
generic_device_ids[0].idVendor = vendor;
generic_device_ids[0].idProduct = product;
generic_device_ids[0].match_flags =
USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
/* register our generic driver with ourselves */
retval = usb_serial_register(&usb_serial_generic_device);
if (retval)
goto exit;
retval = usb_register(&generic_driver);
if (retval)
usb_serial_deregister(&usb_serial_generic_device);
exit:
#endif
return retval;
}
void usb_serial_generic_deregister(void)
{
#ifdef CONFIG_USB_SERIAL_GENERIC
/* remove our generic driver */
usb_deregister(&generic_driver);
usb_serial_deregister(&usb_serial_generic_device);
#endif
}
int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
{
int result = 0;
unsigned long flags;
dbg("%s - port %d", __func__, port->number);
/* clear the throttle flags */
spin_lock_irqsave(&port->lock, flags);
port->throttled = 0;
port->throttle_req = 0;
spin_unlock_irqrestore(&port->lock, flags);
/* if we have a bulk endpoint, start reading from it */
if (port->bulk_in_size)
result = usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
return result;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_open);
static void generic_cleanup(struct usb_serial_port *port)
{
struct usb_serial *serial = port->serial;
unsigned long flags;
dbg("%s - port %d", __func__, port->number);
if (serial->dev) {
/* shutdown any bulk transfers that might be going on */
if (port->bulk_out_size) {
usb_kill_urb(port->write_urb);
spin_lock_irqsave(&port->lock, flags);
kfifo_reset_out(&port->write_fifo);
spin_unlock_irqrestore(&port->lock, flags);
}
if (port->bulk_in_size)
usb_kill_urb(port->read_urb);
}
}
void usb_serial_generic_close(struct usb_serial_port *port)
{
dbg("%s - port %d", __func__, port->number);
generic_cleanup(port);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_close);
static int usb_serial_multi_urb_write(struct tty_struct *tty,
struct usb_serial_port *port, const unsigned char *buf, int count)
{
unsigned long flags;
struct urb *urb;
unsigned char *buffer;
int status;
int towrite;
int bwrite = 0;
dbg("%s - port %d", __func__, port->number);
if (count == 0)
dbg("%s - write request of 0 bytes", __func__);
while (count > 0) {
towrite = (count > port->bulk_out_size) ?
port->bulk_out_size : count;
spin_lock_irqsave(&port->lock, flags);
if (port->urbs_in_flight >
port->serial->type->max_in_flight_urbs) {
spin_unlock_irqrestore(&port->lock, flags);
dbg("%s - write limit hit", __func__);
return bwrite;
}
port->tx_bytes_flight += towrite;
port->urbs_in_flight++;
spin_unlock_irqrestore(&port->lock, flags);
buffer = kmalloc(towrite, GFP_ATOMIC);
if (!buffer) {
dev_err(&port->dev,
"%s ran out of kernel memory for urb ...\n", __func__);
goto error_no_buffer;
}
urb = usb_alloc_urb(0, GFP_ATOMIC);
if (!urb) {
dev_err(&port->dev, "%s - no more free urbs\n",
__func__);
goto error_no_urb;
}
/* Copy data */
memcpy(buffer, buf + bwrite, towrite);
usb_serial_debug_data(debug, &port->dev, __func__,
towrite, buffer);
/* fill the buffer and send it */
usb_fill_bulk_urb(urb, port->serial->dev,
usb_sndbulkpipe(port->serial->dev,
port->bulk_out_endpointAddress),
buffer, towrite,
usb_serial_generic_write_bulk_callback, port);
status = usb_submit_urb(urb, GFP_ATOMIC);
if (status) {
dev_err(&port->dev,
"%s - failed submitting write urb, error %d\n",
__func__, status);
goto error;
}
/* This urb is the responsibility of the host driver now */
usb_free_urb(urb);
dbg("%s write: %d", __func__, towrite);
count -= towrite;
bwrite += towrite;
}
return bwrite;
error:
usb_free_urb(urb);
error_no_urb:
kfree(buffer);
error_no_buffer:
spin_lock_irqsave(&port->lock, flags);
port->urbs_in_flight--;
port->tx_bytes_flight -= towrite;
spin_unlock_irqrestore(&port->lock, flags);
return bwrite;
}
/**
* usb_serial_generic_write_start - kick off an URB write
* @port: Pointer to the &struct usb_serial_port data
*
* Returns the number of bytes queued on success. This will be zero if there
* was nothing to send. Otherwise, it returns a negative errno value
*/
static int usb_serial_generic_write_start(struct usb_serial_port *port)
{
unsigned char *data;
int result;
int count;
unsigned long flags;
bool start_io;
/* Atomically determine whether we can and need to start a USB
* operation. */
spin_lock_irqsave(&port->lock, flags);
if (port->write_urb_busy)
start_io = false;
else {
start_io = (kfifo_len(&port->write_fifo) != 0);
port->write_urb_busy = start_io;
}
spin_unlock_irqrestore(&port->lock, flags);
if (!start_io)
return 0;
data = port->write_urb->transfer_buffer;
count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
usb_serial_debug_data(debug, &port->dev, __func__, count, data);
port->write_urb->transfer_buffer_length = count;
/* send the data out the bulk port */
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);
/* don't have to grab the lock here, as we will
retry if != 0 */
port->write_urb_busy = 0;
return result;
}
spin_lock_irqsave(&port->lock, flags);
port->tx_bytes_flight += count;
spin_unlock_irqrestore(&port->lock, flags);
return count;
}
/**
* usb_serial_generic_write - generic write function for serial USB devices
* @tty: Pointer to &struct tty_struct for the device
* @port: Pointer to the &usb_serial_port structure for the device
* @buf: Pointer to the data to write
* @count: Number of bytes to write
*
* Returns the number of characters actually written, which may be anything
* from zero to @count. If an error occurs, it returns the negative errno
* value.
*/
int usb_serial_generic_write(struct tty_struct *tty,
struct usb_serial_port *port, const unsigned char *buf, int count)
{
struct usb_serial *serial = port->serial;
int result;
dbg("%s - port %d", __func__, port->number);
/* only do something if we have a bulk out endpoint */
if (!port->bulk_out_size)
return -ENODEV;
if (count == 0) {
dbg("%s - write request of 0 bytes", __func__);
return 0;
}
if (serial->type->max_in_flight_urbs)
return usb_serial_multi_urb_write(tty, port,
buf, count);
count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
result = usb_serial_generic_write_start(port);
if (result >= 0)
result = count;
return result;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_write);
int usb_serial_generic_write_room(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
struct usb_serial *serial = port->serial;
unsigned long flags;
int room = 0;
dbg("%s - port %d", __func__, port->number);
if (!port->bulk_out_size)
return 0;
spin_lock_irqsave(&port->lock, flags);
if (serial->type->max_in_flight_urbs) {
if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
room = port->bulk_out_size *
(serial->type->max_in_flight_urbs -
port->urbs_in_flight);
} else {
room = kfifo_avail(&port->write_fifo);
}
spin_unlock_irqrestore(&port->lock, flags);
dbg("%s - returns %d", __func__, room);
return room;
}
int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
struct usb_serial *serial = port->serial;
unsigned long flags;
int chars;
dbg("%s - port %d", __func__, port->number);
if (!port->bulk_out_size)
return 0;
spin_lock_irqsave(&port->lock, flags);
if (serial->type->max_in_flight_urbs)
chars = port->tx_bytes_flight;
else
chars = kfifo_len(&port->write_fifo) + port->tx_bytes_flight;
spin_unlock_irqrestore(&port->lock, flags);
dbg("%s - returns %d", __func__, chars);
return chars;
}
int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
gfp_t mem_flags)
{
int result;
result = usb_submit_urb(port->read_urb, mem_flags);
if (result && result != -EPERM) {
dev_err(&port->dev,
"%s - failed submitting read urb, error %d\n",
__func__, result);
}
return result;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urb);
/* Push data to tty layer and resubmit the bulk read URB */
static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
{
struct urb *urb = port->read_urb;
struct tty_struct *tty = tty_port_tty_get(&port->port);
char *ch = (char *)urb->transfer_buffer;
int i;
if (!tty)
goto done;
/* The per character mucking around with sysrq path it too slow for
stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
where the USB serial is not a console anyway */
if (!port->port.console || !port->sysrq)
tty_insert_flip_string(tty, ch, urb->actual_length);
else {
/* Push data to tty */
for (i = 0; i < urb->actual_length; i++, ch++) {
if (!usb_serial_handle_sysrq_char(tty, port, *ch))
tty_insert_flip_char(tty, *ch, TTY_NORMAL);
}
}
tty_flip_buffer_push(tty);
tty_kref_put(tty);
done:
usb_serial_generic_submit_read_urb(port, GFP_ATOMIC);
}
void usb_serial_generic_read_bulk_callback(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
unsigned char *data = urb->transfer_buffer;
int status = urb->status;
unsigned long flags;
dbg("%s - port %d", __func__, port->number);
if (unlikely(status != 0)) {
dbg("%s - nonzero read bulk status received: %d",
__func__, status);
return;
}
usb_serial_debug_data(debug, &port->dev, __func__,
urb->actual_length, data);
/* Throttle the device if requested by tty */
spin_lock_irqsave(&port->lock, flags);
port->throttled = port->throttle_req;
if (!port->throttled) {
spin_unlock_irqrestore(&port->lock, flags);
flush_and_resubmit_read_urb(port);
} else
spin_unlock_irqrestore(&port->lock, flags);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
void usb_serial_generic_write_bulk_callback(struct urb *urb)
{
unsigned long flags;
struct usb_serial_port *port = urb->context;
int status = urb->status;
dbg("%s - port %d", __func__, port->number);
if (port->serial->type->max_in_flight_urbs) {
kfree(urb->transfer_buffer);
spin_lock_irqsave(&port->lock, flags);
--port->urbs_in_flight;
port->tx_bytes_flight -= urb->transfer_buffer_length;
if (port->urbs_in_flight < 0)
port->urbs_in_flight = 0;
spin_unlock_irqrestore(&port->lock, flags);
} else {
spin_lock_irqsave(&port->lock, flags);
port->tx_bytes_flight -= urb->transfer_buffer_length;
port->write_urb_busy = 0;
spin_unlock_irqrestore(&port->lock, flags);
if (status) {
spin_lock_irqsave(&port->lock, flags);
kfifo_reset_out(&port->write_fifo);
spin_unlock_irqrestore(&port->lock, flags);
} else {
usb_serial_generic_write_start(port);
}
}
if (status)
dbg("%s - non-zero urb status: %d", __func__, status);
usb_serial_port_softint(port);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
void usb_serial_generic_throttle(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
unsigned long flags;
dbg("%s - port %d", __func__, port->number);
/* Set the throttle request flag. It will be picked up
* by usb_serial_generic_read_bulk_callback(). */
spin_lock_irqsave(&port->lock, flags);
port->throttle_req = 1;
spin_unlock_irqrestore(&port->lock, flags);
}
void usb_serial_generic_unthrottle(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
int was_throttled;
unsigned long flags;
dbg("%s - port %d", __func__, port->number);
/* Clear the throttle flags */
spin_lock_irqsave(&port->lock, flags);
was_throttled = port->throttled;
port->throttled = port->throttle_req = 0;
spin_unlock_irqrestore(&port->lock, flags);
if (was_throttled) {
/* Resume reading from device */
flush_and_resubmit_read_urb(port);
}
}
#ifdef CONFIG_MAGIC_SYSRQ
int usb_serial_handle_sysrq_char(struct tty_struct *tty,
struct usb_serial_port *port, unsigned int ch)
{
if (port->sysrq && port->port.console) {
if (ch && time_before(jiffies, port->sysrq)) {
handle_sysrq(ch, tty);
port->sysrq = 0;
return 1;
}
port->sysrq = 0;
}
return 0;
}
#else
int usb_serial_handle_sysrq_char(struct tty_struct *tty,
struct usb_serial_port *port, unsigned int ch)
{
return 0;
}
#endif
EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
int usb_serial_handle_break(struct usb_serial_port *port)
{
if (!port->sysrq) {
port->sysrq = jiffies + HZ*5;
return 1;
}
port->sysrq = 0;
return 0;
}
EXPORT_SYMBOL_GPL(usb_serial_handle_break);
int usb_serial_generic_resume(struct usb_serial *serial)
{
struct usb_serial_port *port;
int i, c = 0, r;
for (i = 0; i < serial->num_ports; i++) {
port = serial->port[i];
if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
continue;
if (port->read_urb) {
r = usb_submit_urb(port->read_urb, GFP_NOIO);
if (r < 0)
c++;
}
if (port->write_urb) {
r = usb_serial_generic_write_start(port);
if (r < 0)
c++;
}
}
return c ? -EIO : 0;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
void usb_serial_generic_disconnect(struct usb_serial *serial)
{
int i;
dbg("%s", __func__);
/* stop reads and writes on all ports */
for (i = 0; i < serial->num_ports; ++i)
generic_cleanup(serial->port[i]);
}
void usb_serial_generic_release(struct usb_serial *serial)
{
dbg("%s", __func__);
}