b507cc9710
Nobody should be using the generic usb-serial for anything other than testing. Still, it's not a good thing that it's easy to lock up. There is a traceback from NMI oopser here: https://bugzilla.redhat.com/show_bug.cgi?id=431379 But in short, if a line discipline has a chance to echo anything, input can loop back a write method. So, don't call tty_flip_buffer_push from under a lock taken on write path. Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
423 lines
11 KiB
C
423 lines
11 KiB
C
/*
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* USB Serial Converter Generic functions
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*
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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/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 <asm/uaccess.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 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_interrupt_in = NUM_DONT_CARE,
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.num_bulk_in = NUM_DONT_CARE,
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.num_bulk_out = NUM_DONT_CARE,
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.num_ports = 1,
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.shutdown = usb_serial_generic_shutdown,
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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 = 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 usb_serial_port *port, struct file *filp)
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{
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struct usb_serial *serial = port->serial;
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int result = 0;
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unsigned long flags;
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dbg("%s - port %d", __FUNCTION__, port->number);
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/* force low_latency on so that our tty_push actually forces the data through,
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otherwise it is scheduled, and with high data rates (like with OHCI) data
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can get lost. */
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if (port->tty)
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port->tty->low_latency = 1;
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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 (serial->num_bulk_in) {
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/* Start reading from the device */
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usb_fill_bulk_urb (port->read_urb, serial->dev,
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usb_rcvbulkpipe(serial->dev, port->bulk_in_endpointAddress),
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port->read_urb->transfer_buffer,
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port->read_urb->transfer_buffer_length,
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((serial->type->read_bulk_callback) ?
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serial->type->read_bulk_callback :
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usb_serial_generic_read_bulk_callback),
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port);
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result = usb_submit_urb(port->read_urb, GFP_KERNEL);
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if (result)
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dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, 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_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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dbg("%s - port %d", __FUNCTION__, port->number);
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if (serial->dev) {
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/* shutdown any bulk reads that might be going on */
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if (serial->num_bulk_out)
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usb_kill_urb(port->write_urb);
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if (serial->num_bulk_in)
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usb_kill_urb(port->read_urb);
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}
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}
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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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#ifdef CONFIG_PM
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/*
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* If this is an autoresume, don't submit URBs.
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* They will be submitted in the open function instead.
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*/
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if (serial->dev->auto_pm)
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return 0;
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#endif
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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 (port->open_count && 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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}
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return c ? -EIO : 0;
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}
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void usb_serial_generic_close (struct usb_serial_port *port, struct file * filp)
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{
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dbg("%s - port %d", __FUNCTION__, port->number);
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generic_cleanup (port);
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}
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int usb_serial_generic_write(struct usb_serial_port *port, const unsigned char *buf, int count)
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{
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struct usb_serial *serial = port->serial;
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int result;
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unsigned char *data;
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dbg("%s - port %d", __FUNCTION__, port->number);
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if (count == 0) {
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dbg("%s - write request of 0 bytes", __FUNCTION__);
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return (0);
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}
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/* only do something if we have a bulk out endpoint */
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if (serial->num_bulk_out) {
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unsigned long flags;
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spin_lock_irqsave(&port->lock, flags);
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if (port->write_urb_busy) {
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spin_unlock_irqrestore(&port->lock, flags);
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dbg("%s - already writing", __FUNCTION__);
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return 0;
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}
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port->write_urb_busy = 1;
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spin_unlock_irqrestore(&port->lock, flags);
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count = (count > port->bulk_out_size) ? port->bulk_out_size : count;
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memcpy (port->write_urb->transfer_buffer, buf, count);
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data = port->write_urb->transfer_buffer;
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usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, data);
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/* set up our urb */
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usb_fill_bulk_urb (port->write_urb, serial->dev,
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usb_sndbulkpipe (serial->dev,
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port->bulk_out_endpointAddress),
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port->write_urb->transfer_buffer, count,
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((serial->type->write_bulk_callback) ?
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serial->type->write_bulk_callback :
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usb_serial_generic_write_bulk_callback), port);
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/* send the data out the bulk port */
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port->write_urb_busy = 1;
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result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
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if (result) {
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dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__, result);
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/* don't have to grab the lock here, as we will retry if != 0 */
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port->write_urb_busy = 0;
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} else
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result = count;
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return result;
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}
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/* no bulk out, so return 0 bytes written */
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return 0;
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}
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int usb_serial_generic_write_room (struct usb_serial_port *port)
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{
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struct usb_serial *serial = port->serial;
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int room = 0;
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dbg("%s - port %d", __FUNCTION__, port->number);
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if (serial->num_bulk_out) {
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if (!(port->write_urb_busy))
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room = port->bulk_out_size;
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}
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dbg("%s - returns %d", __FUNCTION__, room);
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return (room);
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}
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int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port)
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{
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struct usb_serial *serial = port->serial;
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int chars = 0;
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dbg("%s - port %d", __FUNCTION__, port->number);
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if (serial->num_bulk_out) {
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if (port->write_urb_busy)
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chars = port->write_urb->transfer_buffer_length;
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}
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dbg("%s - returns %d", __FUNCTION__, chars);
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return (chars);
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}
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static void resubmit_read_urb(struct usb_serial_port *port, gfp_t mem_flags)
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{
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struct urb *urb = port->read_urb;
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struct usb_serial *serial = port->serial;
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int result;
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/* Continue reading from device */
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usb_fill_bulk_urb (urb, serial->dev,
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usb_rcvbulkpipe (serial->dev,
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port->bulk_in_endpointAddress),
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urb->transfer_buffer,
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urb->transfer_buffer_length,
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((serial->type->read_bulk_callback) ?
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serial->type->read_bulk_callback :
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usb_serial_generic_read_bulk_callback), port);
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result = usb_submit_urb(urb, mem_flags);
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if (result)
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dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
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}
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/* Push data to tty layer and resubmit the bulk read URB */
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static void flush_and_resubmit_read_urb (struct usb_serial_port *port)
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{
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struct urb *urb = port->read_urb;
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struct tty_struct *tty = port->tty;
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int room;
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/* Push data to tty */
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if (tty && urb->actual_length) {
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room = tty_buffer_request_room(tty, urb->actual_length);
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if (room) {
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tty_insert_flip_string(tty, urb->transfer_buffer, room);
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tty_flip_buffer_push(tty);
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}
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}
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resubmit_read_urb(port, GFP_ATOMIC);
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}
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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 = (struct usb_serial_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", __FUNCTION__, 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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__FUNCTION__, status);
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return;
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}
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usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);
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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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if (!(port->throttled = port->throttle_req)) {
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spin_unlock_irqrestore(&port->lock, flags);
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flush_and_resubmit_read_urb(port);
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} else {
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spin_unlock_irqrestore(&port->lock, flags);
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}
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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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struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
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int status = urb->status;
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dbg("%s - port %d", __FUNCTION__, port->number);
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port->write_urb_busy = 0;
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if (status) {
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dbg("%s - nonzero write bulk status received: %d",
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__FUNCTION__, status);
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return;
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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 usb_serial_port *port)
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{
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unsigned long flags;
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dbg("%s - port %d", __FUNCTION__, 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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void usb_serial_generic_unthrottle (struct usb_serial_port *port)
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{
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int was_throttled;
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unsigned long flags;
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dbg("%s - port %d", __FUNCTION__, port->number);
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/* Clear the throttle flags */
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spin_lock_irqsave(&port->lock, flags);
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was_throttled = port->throttled;
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port->throttled = port->throttle_req = 0;
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spin_unlock_irqrestore(&port->lock, flags);
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if (was_throttled) {
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/* Resume reading from device */
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resubmit_read_urb(port, GFP_KERNEL);
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}
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}
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void usb_serial_generic_shutdown (struct usb_serial *serial)
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{
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int i;
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dbg("%s", __FUNCTION__);
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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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}
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