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![Joris van Rantwijk](/assets/img/avatar_default.png)
The generic usbserial driver in Linux 2.6.31 halts its receiving channel in response to throttle requests from the line discipline. Unfortunately it drops the contents of the first URB received after throttling takes effect. This patch corrects that problem. Signed-off-by: Joris van Rantwijk <jorispubl@xs4all.nl> Acked-by: Johan Hovold <jhovold@gmail.com> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
620 lines
16 KiB
C
620 lines
16 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 <linux/uaccess.h>
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#include <linux/kfifo.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_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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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", __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 (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,
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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,
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"%s - failed resubmitting read urb, error %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_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", __func__, 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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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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static int usb_serial_multi_urb_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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unsigned long flags;
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struct urb *urb;
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unsigned char *buffer;
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int status;
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int towrite;
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int bwrite = 0;
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dbg("%s - port %d", __func__, port->number);
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if (count == 0)
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dbg("%s - write request of 0 bytes", __func__);
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while (count > 0) {
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towrite = (count > port->bulk_out_size) ?
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port->bulk_out_size : count;
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spin_lock_irqsave(&port->lock, flags);
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if (port->urbs_in_flight >
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port->serial->type->max_in_flight_urbs) {
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spin_unlock_irqrestore(&port->lock, flags);
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dbg("%s - write limit hit\n", __func__);
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return bwrite;
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}
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port->tx_bytes_flight += towrite;
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port->urbs_in_flight++;
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spin_unlock_irqrestore(&port->lock, flags);
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buffer = kmalloc(towrite, GFP_ATOMIC);
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if (!buffer) {
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dev_err(&port->dev,
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"%s ran out of kernel memory for urb ...\n", __func__);
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goto error_no_buffer;
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}
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urb = usb_alloc_urb(0, GFP_ATOMIC);
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if (!urb) {
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dev_err(&port->dev, "%s - no more free urbs\n",
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__func__);
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goto error_no_urb;
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}
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/* Copy data */
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memcpy(buffer, buf + bwrite, towrite);
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usb_serial_debug_data(debug, &port->dev, __func__,
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towrite, buffer);
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/* fill the buffer and send it */
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usb_fill_bulk_urb(urb, port->serial->dev,
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usb_sndbulkpipe(port->serial->dev,
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port->bulk_out_endpointAddress),
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buffer, towrite,
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usb_serial_generic_write_bulk_callback, port);
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status = usb_submit_urb(urb, GFP_ATOMIC);
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if (status) {
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dev_err(&port->dev,
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"%s - failed submitting write urb, error %d\n",
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__func__, status);
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goto error;
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}
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/* This urb is the responsibility of the host driver now */
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usb_free_urb(urb);
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dbg("%s write: %d", __func__, towrite);
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count -= towrite;
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bwrite += towrite;
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}
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return bwrite;
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error:
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usb_free_urb(urb);
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error_no_urb:
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kfree(buffer);
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error_no_buffer:
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spin_lock_irqsave(&port->lock, flags);
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port->urbs_in_flight--;
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port->tx_bytes_flight -= towrite;
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spin_unlock_irqrestore(&port->lock, flags);
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return bwrite;
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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 the number of bytes queued on success. This will be zero if there
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* was nothing to send. Otherwise, it returns 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 usb_serial *serial = port->serial;
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unsigned char *data;
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int result;
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int count;
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unsigned long flags;
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bool start_io;
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/* Atomically determine whether we can and need to start a USB
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* operation. */
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spin_lock_irqsave(&port->lock, flags);
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if (port->write_urb_busy)
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start_io = false;
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else {
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start_io = (__kfifo_len(port->write_fifo) != 0);
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port->write_urb_busy = start_io;
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}
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spin_unlock_irqrestore(&port->lock, flags);
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if (!start_io)
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return 0;
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data = port->write_urb->transfer_buffer;
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count = kfifo_get(port->write_fifo, data, port->bulk_out_size);
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usb_serial_debug_data(debug, &port->dev, __func__, 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),
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port);
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/* send the data out the bulk port */
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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,
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"%s - failed submitting write urb, error %d\n",
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__func__, result);
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/* don't have to grab the lock here, as we will
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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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/**
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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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struct usb_serial *serial = port->serial;
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int result;
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dbg("%s - port %d", __func__, port->number);
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if (count == 0) {
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dbg("%s - write request of 0 bytes", __func__);
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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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return 0;
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if (serial->type->max_in_flight_urbs)
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return usb_serial_multi_urb_write(tty, port,
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buf, count);
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count = kfifo_put(port->write_fifo, buf, count);
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result = usb_serial_generic_write_start(port);
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if (result >= 0)
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result = count;
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return result;
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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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struct usb_serial *serial = port->serial;
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unsigned long flags;
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int room = 0;
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dbg("%s - port %d", __func__, port->number);
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spin_lock_irqsave(&port->lock, flags);
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if (serial->type->max_in_flight_urbs) {
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if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
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room = port->bulk_out_size *
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(serial->type->max_in_flight_urbs -
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port->urbs_in_flight);
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} else if (serial->num_bulk_out)
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room = port->write_fifo->size - __kfifo_len(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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struct usb_serial *serial = port->serial;
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int chars = 0;
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unsigned long flags;
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dbg("%s - port %d", __func__, port->number);
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if (serial->type->max_in_flight_urbs) {
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spin_lock_irqsave(&port->lock, flags);
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chars = port->tx_bytes_flight;
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spin_unlock_irqrestore(&port->lock, flags);
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} else if (serial->num_bulk_out)
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chars = kfifo_len(port->write_fifo);
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dbg("%s - returns %d", __func__, chars);
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return chars;
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}
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void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
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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,
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"%s - failed resubmitting read urb, error %d\n",
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__func__, result);
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}
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EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);
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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 = tty_port_tty_get(&port->port);
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char *ch = (char *)urb->transfer_buffer;
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int i;
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if (!tty)
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goto done;
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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->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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/* Push data to tty */
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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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done:
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usb_serial_generic_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 = 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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/* 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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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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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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dbg("%s - port %d", __func__, port->number);
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if (port->serial->type->max_in_flight_urbs) {
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spin_lock_irqsave(&port->lock, flags);
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--port->urbs_in_flight;
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port->tx_bytes_flight -= urb->transfer_buffer_length;
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if (port->urbs_in_flight < 0)
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port->urbs_in_flight = 0;
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spin_unlock_irqrestore(&port->lock, flags);
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if (status) {
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dbg("%s - nonzero multi-urb write bulk status "
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"received: %d", __func__, status);
|
|
return;
|
|
}
|
|
} else {
|
|
port->write_urb_busy = 0;
|
|
|
|
if (status) {
|
|
dbg("%s - nonzero multi-urb write bulk status "
|
|
"received: %d", __func__, status);
|
|
kfifo_reset(port->write_fifo);
|
|
} else
|
|
usb_serial_generic_write_start(port);
|
|
}
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
int usb_serial_handle_sysrq_char(struct tty_struct *tty,
|
|
struct usb_serial_port *port, unsigned int ch)
|
|
{
|
|
if (port->sysrq && port->console) {
|
|
if (ch && time_before(jiffies, port->sysrq)) {
|
|
handle_sysrq(ch, tty);
|
|
port->sysrq = 0;
|
|
return 1;
|
|
}
|
|
port->sysrq = 0;
|
|
}
|
|
return 0;
|
|
}
|
|
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 (!port->port.count)
|
|
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__);
|
|
}
|