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56a1df46c1
Return immediately from generic process_read_urb if urb is empty. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
521 lines
13 KiB
C
521 lines
13 KiB
C
/*
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* USB Serial Converter Generic functions
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*
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* Copyright (C) 2010 Johan Hovold (jhovold@gmail.com)
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* Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/sysrq.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/usb.h>
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#include <linux/usb/serial.h>
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#include <linux/uaccess.h>
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#include <linux/kfifo.h>
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#include <linux/serial.h>
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static int debug;
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#ifdef CONFIG_USB_SERIAL_GENERIC
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static int generic_probe(struct usb_interface *interface,
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const struct usb_device_id *id);
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static __u16 vendor = 0x05f9;
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static __u16 product = 0xffff;
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module_param(vendor, ushort, 0);
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MODULE_PARM_DESC(vendor, "User specified USB idVendor");
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module_param(product, ushort, 0);
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MODULE_PARM_DESC(product, "User specified USB idProduct");
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static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
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/* we want to look at all devices, as the vendor/product id can change
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* depending on the command line argument */
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static const struct usb_device_id generic_serial_ids[] = {
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{.driver_info = 42},
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{}
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};
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static struct usb_driver generic_driver = {
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.name = "usbserial_generic",
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.probe = generic_probe,
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.disconnect = usb_serial_disconnect,
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.id_table = generic_serial_ids,
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.no_dynamic_id = 1,
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};
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/* All of the device info needed for the Generic Serial Converter */
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struct usb_serial_driver usb_serial_generic_device = {
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.driver = {
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.owner = THIS_MODULE,
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.name = "generic",
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},
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.id_table = generic_device_ids,
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.usb_driver = &generic_driver,
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.num_ports = 1,
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.disconnect = usb_serial_generic_disconnect,
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.release = usb_serial_generic_release,
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.throttle = usb_serial_generic_throttle,
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.unthrottle = usb_serial_generic_unthrottle,
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.resume = usb_serial_generic_resume,
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};
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static int generic_probe(struct usb_interface *interface,
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const struct usb_device_id *id)
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{
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const struct usb_device_id *id_pattern;
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id_pattern = usb_match_id(interface, generic_device_ids);
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if (id_pattern != NULL)
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return usb_serial_probe(interface, id);
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return -ENODEV;
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}
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#endif
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int usb_serial_generic_register(int _debug)
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{
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int retval = 0;
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debug = _debug;
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#ifdef CONFIG_USB_SERIAL_GENERIC
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generic_device_ids[0].idVendor = vendor;
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generic_device_ids[0].idProduct = product;
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generic_device_ids[0].match_flags =
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USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
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/* register our generic driver with ourselves */
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retval = usb_serial_register(&usb_serial_generic_device);
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if (retval)
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goto exit;
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retval = usb_register(&generic_driver);
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if (retval)
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usb_serial_deregister(&usb_serial_generic_device);
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exit:
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#endif
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return retval;
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}
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void usb_serial_generic_deregister(void)
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{
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#ifdef CONFIG_USB_SERIAL_GENERIC
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/* remove our generic driver */
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usb_deregister(&generic_driver);
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usb_serial_deregister(&usb_serial_generic_device);
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#endif
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}
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int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
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{
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int result = 0;
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unsigned long flags;
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dbg("%s - port %d", __func__, port->number);
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/* clear the throttle flags */
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spin_lock_irqsave(&port->lock, flags);
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port->throttled = 0;
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port->throttle_req = 0;
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spin_unlock_irqrestore(&port->lock, flags);
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/* if we have a bulk endpoint, start reading from it */
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if (port->bulk_in_size)
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result = usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
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return result;
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_open);
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static void generic_cleanup(struct usb_serial_port *port)
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{
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struct usb_serial *serial = port->serial;
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unsigned long flags;
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int i;
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dbg("%s - port %d", __func__, port->number);
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if (serial->dev) {
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/* shutdown any bulk transfers that might be going on */
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if (port->bulk_out_size) {
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usb_kill_urb(port->write_urb);
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for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
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usb_kill_urb(port->write_urbs[i]);
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spin_lock_irqsave(&port->lock, flags);
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kfifo_reset_out(&port->write_fifo);
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spin_unlock_irqrestore(&port->lock, flags);
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}
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if (port->bulk_in_size)
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usb_kill_urb(port->read_urb);
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}
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}
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void usb_serial_generic_close(struct usb_serial_port *port)
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{
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dbg("%s - port %d", __func__, port->number);
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generic_cleanup(port);
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_close);
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int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
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void *dest, size_t size)
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{
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return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
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}
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/**
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* usb_serial_generic_write_start - kick off an URB write
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* @port: Pointer to the &struct usb_serial_port data
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*
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* Returns zero on success, or a negative errno value
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*/
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static int usb_serial_generic_write_start(struct usb_serial_port *port)
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{
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struct urb *urb;
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int count, result;
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unsigned long flags;
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int i;
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if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
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return 0;
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retry:
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spin_lock_irqsave(&port->lock, flags);
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if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
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clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
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spin_unlock_irqrestore(&port->lock, flags);
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return 0;
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}
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i = (int)find_first_bit(&port->write_urbs_free,
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ARRAY_SIZE(port->write_urbs));
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spin_unlock_irqrestore(&port->lock, flags);
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urb = port->write_urbs[i];
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count = port->serial->type->prepare_write_buffer(port,
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urb->transfer_buffer,
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port->bulk_out_size);
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urb->transfer_buffer_length = count;
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usb_serial_debug_data(debug, &port->dev, __func__, count,
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urb->transfer_buffer);
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result = usb_submit_urb(urb, GFP_ATOMIC);
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if (result) {
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dev_err(&port->dev, "%s - error submitting urb: %d\n",
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__func__, result);
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clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
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return result;
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}
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clear_bit(i, &port->write_urbs_free);
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spin_lock_irqsave(&port->lock, flags);
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port->tx_bytes += count;
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spin_unlock_irqrestore(&port->lock, flags);
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/* Try sending off another urb, unless in irq context (in which case
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* there will be no free urb). */
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if (!in_irq())
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goto retry;
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clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
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return 0;
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}
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/**
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* usb_serial_generic_write - generic write function for serial USB devices
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* @tty: Pointer to &struct tty_struct for the device
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* @port: Pointer to the &usb_serial_port structure for the device
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* @buf: Pointer to the data to write
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* @count: Number of bytes to write
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*
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* Returns the number of characters actually written, which may be anything
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* from zero to @count. If an error occurs, it returns the negative errno
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* value.
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*/
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int usb_serial_generic_write(struct tty_struct *tty,
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struct usb_serial_port *port, const unsigned char *buf, int count)
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{
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int result;
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dbg("%s - port %d", __func__, port->number);
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/* only do something if we have a bulk out endpoint */
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if (!port->bulk_out_size)
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return -ENODEV;
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if (!count)
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return 0;
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count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
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result = usb_serial_generic_write_start(port);
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if (result)
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return result;
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return count;
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_write);
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int usb_serial_generic_write_room(struct tty_struct *tty)
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{
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struct usb_serial_port *port = tty->driver_data;
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unsigned long flags;
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int room;
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dbg("%s - port %d", __func__, port->number);
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if (!port->bulk_out_size)
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return 0;
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spin_lock_irqsave(&port->lock, flags);
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room = kfifo_avail(&port->write_fifo);
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spin_unlock_irqrestore(&port->lock, flags);
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dbg("%s - returns %d", __func__, room);
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return room;
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}
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int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
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{
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struct usb_serial_port *port = tty->driver_data;
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unsigned long flags;
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int chars;
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dbg("%s - port %d", __func__, port->number);
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if (!port->bulk_out_size)
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return 0;
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spin_lock_irqsave(&port->lock, flags);
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chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
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spin_unlock_irqrestore(&port->lock, flags);
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dbg("%s - returns %d", __func__, chars);
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return chars;
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}
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int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
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gfp_t mem_flags)
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{
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int result;
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result = usb_submit_urb(port->read_urb, mem_flags);
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if (result && result != -EPERM) {
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dev_err(&port->dev, "%s - error submitting urb: %d\n",
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__func__, result);
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}
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return result;
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urb);
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void usb_serial_generic_process_read_urb(struct urb *urb)
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{
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struct usb_serial_port *port = urb->context;
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struct tty_struct *tty;
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char *ch = (char *)urb->transfer_buffer;
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int i;
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if (!urb->actual_length)
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return;
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tty = tty_port_tty_get(&port->port);
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if (!tty)
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return;
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/* The per character mucking around with sysrq path it too slow for
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stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
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where the USB serial is not a console anyway */
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if (!port->port.console || !port->sysrq)
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tty_insert_flip_string(tty, ch, urb->actual_length);
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else {
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for (i = 0; i < urb->actual_length; i++, ch++) {
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if (!usb_serial_handle_sysrq_char(tty, port, *ch))
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tty_insert_flip_char(tty, *ch, TTY_NORMAL);
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}
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}
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tty_flip_buffer_push(tty);
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tty_kref_put(tty);
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
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void usb_serial_generic_read_bulk_callback(struct urb *urb)
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{
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struct usb_serial_port *port = urb->context;
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unsigned char *data = urb->transfer_buffer;
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int status = urb->status;
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unsigned long flags;
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dbg("%s - port %d", __func__, port->number);
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if (unlikely(status != 0)) {
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dbg("%s - nonzero read bulk status received: %d",
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__func__, status);
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return;
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}
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usb_serial_debug_data(debug, &port->dev, __func__,
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urb->actual_length, data);
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port->serial->type->process_read_urb(urb);
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/* Throttle the device if requested by tty */
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spin_lock_irqsave(&port->lock, flags);
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port->throttled = port->throttle_req;
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if (!port->throttled) {
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spin_unlock_irqrestore(&port->lock, flags);
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usb_serial_generic_submit_read_urb(port, GFP_ATOMIC);
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} else
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spin_unlock_irqrestore(&port->lock, flags);
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
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void usb_serial_generic_write_bulk_callback(struct urb *urb)
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{
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unsigned long flags;
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struct usb_serial_port *port = urb->context;
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int status = urb->status;
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int i;
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dbg("%s - port %d", __func__, port->number);
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for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
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if (port->write_urbs[i] == urb)
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break;
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spin_lock_irqsave(&port->lock, flags);
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port->tx_bytes -= urb->transfer_buffer_length;
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set_bit(i, &port->write_urbs_free);
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spin_unlock_irqrestore(&port->lock, flags);
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if (status) {
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dbg("%s - non-zero urb status: %d", __func__, status);
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spin_lock_irqsave(&port->lock, flags);
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kfifo_reset_out(&port->write_fifo);
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spin_unlock_irqrestore(&port->lock, flags);
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} else {
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usb_serial_generic_write_start(port);
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}
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usb_serial_port_softint(port);
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
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void usb_serial_generic_throttle(struct tty_struct *tty)
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{
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struct usb_serial_port *port = tty->driver_data;
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unsigned long flags;
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dbg("%s - port %d", __func__, port->number);
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/* Set the throttle request flag. It will be picked up
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* by usb_serial_generic_read_bulk_callback(). */
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spin_lock_irqsave(&port->lock, flags);
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port->throttle_req = 1;
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spin_unlock_irqrestore(&port->lock, flags);
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
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void usb_serial_generic_unthrottle(struct tty_struct *tty)
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{
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struct usb_serial_port *port = tty->driver_data;
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int was_throttled;
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dbg("%s - port %d", __func__, port->number);
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/* Clear the throttle flags */
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spin_lock_irq(&port->lock);
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was_throttled = port->throttled;
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port->throttled = port->throttle_req = 0;
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spin_unlock_irq(&port->lock);
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if (was_throttled)
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usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
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#ifdef CONFIG_MAGIC_SYSRQ
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int usb_serial_handle_sysrq_char(struct tty_struct *tty,
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struct usb_serial_port *port, unsigned int ch)
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{
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if (port->sysrq && port->port.console) {
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if (ch && time_before(jiffies, port->sysrq)) {
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handle_sysrq(ch, tty);
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port->sysrq = 0;
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return 1;
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}
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port->sysrq = 0;
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}
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return 0;
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}
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#else
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int usb_serial_handle_sysrq_char(struct tty_struct *tty,
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struct usb_serial_port *port, unsigned int ch)
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{
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return 0;
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}
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#endif
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EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
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int usb_serial_handle_break(struct usb_serial_port *port)
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{
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if (!port->sysrq) {
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port->sysrq = jiffies + HZ*5;
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return 1;
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}
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port->sysrq = 0;
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return 0;
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}
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EXPORT_SYMBOL_GPL(usb_serial_handle_break);
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int usb_serial_generic_resume(struct usb_serial *serial)
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{
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struct usb_serial_port *port;
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int i, c = 0, r;
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for (i = 0; i < serial->num_ports; i++) {
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port = serial->port[i];
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if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
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continue;
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if (port->read_urb) {
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r = usb_submit_urb(port->read_urb, GFP_NOIO);
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if (r < 0)
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c++;
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}
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if (port->bulk_out_size) {
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r = usb_serial_generic_write_start(port);
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if (r < 0)
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c++;
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}
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}
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return c ? -EIO : 0;
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
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void usb_serial_generic_disconnect(struct usb_serial *serial)
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{
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int i;
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dbg("%s", __func__);
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/* stop reads and writes on all ports */
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for (i = 0; i < serial->num_ports; ++i)
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generic_cleanup(serial->port[i]);
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}
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void usb_serial_generic_release(struct usb_serial *serial)
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|
{
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|
dbg("%s", __func__);
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|
}
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