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![Oliver Neukum](/assets/img/avatar_default.png)
many serial subdrivers are clearly written as if throttle/unthrottle cannot sleep. This leads to unneeded atomic submissions. This patch converts affected drivers in a way to makes very clear that throttle/unthrottle can sleep. Thus future misdesigns can be avoided and efficiency and reliability improved. This removes any such assumption using GFP_KERNEL and spin_lock_irq() Signed-off-by: Oliver Neukum <oliver@neukum.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
548 lines
14 KiB
C
548 lines
14 KiB
C
/*
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* USB Empeg empeg-car player driver
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*
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* Copyright (C) 2000, 2001
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* Gary Brubaker (xavyer@ix.netcom.com)
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*
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* Copyright (C) 1999 - 2001
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* 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 modify
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* it under the terms of the GNU General Public License, as published by
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* the Free Software Foundation, version 2.
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*
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* See Documentation/usb/usb-serial.txt for more information on using this
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* driver
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*
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* (07/16/2001) gb
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* remove unused code in empeg_close() (thanks to Oliver Neukum for
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* pointing this out) and rewrote empeg_set_termios().
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*
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* (05/30/2001) gkh
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* switched from using spinlock to a semaphore, which fixes lots of
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* problems.
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*
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* (04/08/2001) gb
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* Identify version on module load.
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*
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* (01/22/2001) gb
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* Added write_room() and chars_in_buffer() support.
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*
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* (12/21/2000) gb
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* Moved termio stuff inside the port->active check.
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* Moved MOD_DEC_USE_COUNT to end of empeg_close().
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*
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* (12/03/2000) gb
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* Added tty->ldisc.set_termios(port, tty, NULL) to empeg_open().
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* This notifies the tty driver that the termios have changed.
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*
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* (11/13/2000) gb
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* Moved tty->low_latency = 1 from empeg_read_bulk_callback() to
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* empeg_open() (It only needs to be set once - Doh!)
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*
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* (11/11/2000) gb
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* Updated to work with id_table structure.
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*
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* (11/04/2000) gb
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* Forked this from visor.c, and hacked it up to work with an
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* Empeg ltd. empeg-car player. Constructive criticism welcomed.
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* I would like to say, 'Thank You' to Greg Kroah-Hartman for the
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* use of his code, and for his guidance, advice and patience. :)
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* A 'Thank You' is in order for John Ripley of Empeg ltd for his
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* advice, and patience too.
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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/init.h>
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#include <linux/slab.h>
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#include <linux/tty_flip.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include <linux/usb.h>
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#include <linux/usb/serial.h>
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static int debug;
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/*
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* Version Information
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*/
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#define DRIVER_VERSION "v1.2"
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#define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@kroah.com>, Gary Brubaker <xavyer@ix.netcom.com>"
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#define DRIVER_DESC "USB Empeg Mark I/II Driver"
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#define EMPEG_VENDOR_ID 0x084f
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#define EMPEG_PRODUCT_ID 0x0001
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/* function prototypes for an empeg-car player */
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static int empeg_open(struct tty_struct *tty, struct usb_serial_port *port);
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static void empeg_close(struct usb_serial_port *port);
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static int empeg_write(struct tty_struct *tty, struct usb_serial_port *port,
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const unsigned char *buf,
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int count);
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static int empeg_write_room(struct tty_struct *tty);
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static int empeg_chars_in_buffer(struct tty_struct *tty);
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static void empeg_throttle(struct tty_struct *tty);
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static void empeg_unthrottle(struct tty_struct *tty);
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static int empeg_startup(struct usb_serial *serial);
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static void empeg_init_termios(struct tty_struct *tty);
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static void empeg_write_bulk_callback(struct urb *urb);
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static void empeg_read_bulk_callback(struct urb *urb);
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static struct usb_device_id id_table [] = {
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{ USB_DEVICE(EMPEG_VENDOR_ID, EMPEG_PRODUCT_ID) },
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{ } /* Terminating entry */
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};
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MODULE_DEVICE_TABLE(usb, id_table);
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static struct usb_driver empeg_driver = {
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.name = "empeg",
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.probe = usb_serial_probe,
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.disconnect = usb_serial_disconnect,
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.id_table = id_table,
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.no_dynamic_id = 1,
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};
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static struct usb_serial_driver empeg_device = {
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.driver = {
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.owner = THIS_MODULE,
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.name = "empeg",
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},
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.id_table = id_table,
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.usb_driver = &empeg_driver,
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.num_ports = 1,
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.open = empeg_open,
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.close = empeg_close,
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.throttle = empeg_throttle,
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.unthrottle = empeg_unthrottle,
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.attach = empeg_startup,
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.init_termios = empeg_init_termios,
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.write = empeg_write,
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.write_room = empeg_write_room,
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.chars_in_buffer = empeg_chars_in_buffer,
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.write_bulk_callback = empeg_write_bulk_callback,
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.read_bulk_callback = empeg_read_bulk_callback,
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};
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#define NUM_URBS 16
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#define URB_TRANSFER_BUFFER_SIZE 4096
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static struct urb *write_urb_pool[NUM_URBS];
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static spinlock_t write_urb_pool_lock;
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static int bytes_in;
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static int bytes_out;
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/******************************************************************************
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* Empeg specific driver functions
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******************************************************************************/
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static int empeg_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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dbg("%s - port %d", __func__, port->number);
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bytes_in = 0;
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bytes_out = 0;
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/* Start reading from the device */
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usb_fill_bulk_urb(
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port->read_urb,
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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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empeg_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 submitting read urb, error %d\n",
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__func__, result);
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return result;
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}
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static void empeg_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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/* shutdown our bulk read */
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usb_kill_urb(port->read_urb);
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/* Uncomment the following line if you want to see some statistics in your syslog */
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/* dev_info (&port->dev, "Bytes In = %d Bytes Out = %d\n", bytes_in, bytes_out); */
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}
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static int empeg_write(struct tty_struct *tty, struct usb_serial_port *port,
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const unsigned char *buf, int count)
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{
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struct usb_serial *serial = port->serial;
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struct urb *urb;
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const unsigned char *current_position = buf;
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unsigned long flags;
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int status;
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int i;
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int bytes_sent = 0;
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int transfer_size;
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dbg("%s - port %d", __func__, port->number);
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while (count > 0) {
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/* try to find a free urb in our list of them */
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urb = NULL;
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spin_lock_irqsave(&write_urb_pool_lock, flags);
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for (i = 0; i < NUM_URBS; ++i) {
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if (write_urb_pool[i]->status != -EINPROGRESS) {
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urb = write_urb_pool[i];
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break;
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}
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}
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spin_unlock_irqrestore(&write_urb_pool_lock, flags);
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if (urb == NULL) {
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dbg("%s - no more free urbs", __func__);
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goto exit;
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}
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if (urb->transfer_buffer == NULL) {
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urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE, GFP_ATOMIC);
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if (urb->transfer_buffer == NULL) {
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dev_err(&port->dev,
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"%s no more kernel memory...\n",
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__func__);
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goto exit;
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}
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}
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transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);
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memcpy(urb->transfer_buffer, current_position, transfer_size);
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usb_serial_debug_data(debug, &port->dev, __func__, transfer_size, urb->transfer_buffer);
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/* build up our urb */
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usb_fill_bulk_urb(
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urb,
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serial->dev,
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usb_sndbulkpipe(serial->dev,
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port->bulk_out_endpointAddress),
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urb->transfer_buffer,
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transfer_size,
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empeg_write_bulk_callback,
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port);
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/* send it down the pipe */
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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, "%s - usb_submit_urb(write bulk) failed with status = %d\n", __func__, status);
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bytes_sent = status;
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break;
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}
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current_position += transfer_size;
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bytes_sent += transfer_size;
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count -= transfer_size;
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bytes_out += transfer_size;
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}
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exit:
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return bytes_sent;
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}
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static int empeg_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 i;
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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(&write_urb_pool_lock, flags);
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/* tally up the number of bytes available */
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for (i = 0; i < NUM_URBS; ++i) {
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if (write_urb_pool[i]->status != -EINPROGRESS)
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room += URB_TRANSFER_BUFFER_SIZE;
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}
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spin_unlock_irqrestore(&write_urb_pool_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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static int empeg_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 i;
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int chars = 0;
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dbg("%s - port %d", __func__, port->number);
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spin_lock_irqsave(&write_urb_pool_lock, flags);
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/* tally up the number of bytes waiting */
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for (i = 0; i < NUM_URBS; ++i) {
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if (write_urb_pool[i]->status == -EINPROGRESS)
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chars += URB_TRANSFER_BUFFER_SIZE;
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}
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spin_unlock_irqrestore(&write_urb_pool_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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static void empeg_write_bulk_callback(struct urb *urb)
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{
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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 (status) {
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dbg("%s - nonzero write 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_port_softint(port);
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}
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static void empeg_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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struct tty_struct *tty;
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unsigned char *data = urb->transfer_buffer;
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int result;
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int status = urb->status;
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dbg("%s - port %d", __func__, port->number);
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if (status) {
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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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tty = tty_port_tty_get(&port->port);
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if (urb->actual_length) {
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tty_buffer_request_room(tty, urb->actual_length);
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tty_insert_flip_string(tty, data, urb->actual_length);
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tty_flip_buffer_push(tty);
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bytes_in += urb->actual_length;
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}
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tty_kref_put(tty);
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/* Continue trying to always read */
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usb_fill_bulk_urb(
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port->read_urb,
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port->serial->dev,
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usb_rcvbulkpipe(port->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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empeg_read_bulk_callback,
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port);
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result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
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if (result)
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dev_err(&urb->dev->dev,
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"%s - failed resubmitting read urb, error %d\n",
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__func__, result);
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return;
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}
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static void empeg_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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dbg("%s - port %d", __func__, port->number);
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usb_kill_urb(port->read_urb);
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}
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static void empeg_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 result;
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dbg("%s - port %d", __func__, port->number);
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port->read_urb->dev = port->serial->dev;
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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 submitting read urb, error %d\n",
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__func__, result);
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}
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static int empeg_startup(struct usb_serial *serial)
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{
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int r;
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dbg("%s", __func__);
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if (serial->dev->actconfig->desc.bConfigurationValue != 1) {
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dev_err(&serial->dev->dev, "active config #%d != 1 ??\n",
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serial->dev->actconfig->desc.bConfigurationValue);
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return -ENODEV;
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}
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dbg("%s - reset config", __func__);
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r = usb_reset_configuration(serial->dev);
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/* continue on with initialization */
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return r;
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}
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static void empeg_init_termios(struct tty_struct *tty)
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{
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struct ktermios *termios = tty->termios;
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/*
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* The empeg-car player wants these particular tty settings.
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* You could, for example, change the baud rate, however the
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* player only supports 115200 (currently), so there is really
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* no point in support for changes to the tty settings.
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* (at least for now)
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*
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* The default requirements for this device are:
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*/
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termios->c_iflag
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&= ~(IGNBRK /* disable ignore break */
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| BRKINT /* disable break causes interrupt */
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| PARMRK /* disable mark parity errors */
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| ISTRIP /* disable clear high bit of input characters */
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| INLCR /* disable translate NL to CR */
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| IGNCR /* disable ignore CR */
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| ICRNL /* disable translate CR to NL */
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| IXON); /* disable enable XON/XOFF flow control */
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termios->c_oflag
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&= ~OPOST; /* disable postprocess output characters */
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termios->c_lflag
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&= ~(ECHO /* disable echo input characters */
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| ECHONL /* disable echo new line */
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| ICANON /* disable erase, kill, werase, and rprnt special characters */
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| ISIG /* disable interrupt, quit, and suspend special characters */
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| IEXTEN); /* disable non-POSIX special characters */
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termios->c_cflag
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&= ~(CSIZE /* no size */
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| PARENB /* disable parity bit */
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| CBAUD); /* clear current baud rate */
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termios->c_cflag
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|= CS8; /* character size 8 bits */
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tty_encode_baud_rate(tty, 115200, 115200);
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}
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static int __init empeg_init(void)
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{
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struct urb *urb;
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int i, retval;
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/* create our write urb pool and transfer buffers */
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spin_lock_init(&write_urb_pool_lock);
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for (i = 0; i < NUM_URBS; ++i) {
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urb = usb_alloc_urb(0, GFP_KERNEL);
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write_urb_pool[i] = urb;
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if (urb == NULL) {
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printk(KERN_ERR "empeg: No more urbs???\n");
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continue;
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}
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urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
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GFP_KERNEL);
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if (!urb->transfer_buffer) {
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printk(KERN_ERR "empeg: %s - out of memory for urb "
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"buffers.", __func__);
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continue;
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}
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}
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retval = usb_serial_register(&empeg_device);
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if (retval)
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goto failed_usb_serial_register;
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retval = usb_register(&empeg_driver);
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if (retval)
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goto failed_usb_register;
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printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
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DRIVER_DESC "\n");
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return 0;
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failed_usb_register:
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usb_serial_deregister(&empeg_device);
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failed_usb_serial_register:
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for (i = 0; i < NUM_URBS; ++i) {
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if (write_urb_pool[i]) {
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kfree(write_urb_pool[i]->transfer_buffer);
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usb_free_urb(write_urb_pool[i]);
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}
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}
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return retval;
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}
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static void __exit empeg_exit(void)
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{
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int i;
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unsigned long flags;
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usb_deregister(&empeg_driver);
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usb_serial_deregister(&empeg_device);
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spin_lock_irqsave(&write_urb_pool_lock, flags);
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for (i = 0; i < NUM_URBS; ++i) {
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if (write_urb_pool[i]) {
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/* FIXME - uncomment the following usb_kill_urb call
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* when the host controllers get fixed to set urb->dev
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* = NULL after the urb is finished. Otherwise this
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* call oopses. */
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/* usb_kill_urb(write_urb_pool[i]); */
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kfree(write_urb_pool[i]->transfer_buffer);
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usb_free_urb(write_urb_pool[i]);
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}
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}
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spin_unlock_irqrestore(&write_urb_pool_lock, flags);
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}
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module_init(empeg_init);
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module_exit(empeg_exit);
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE("GPL");
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module_param(debug, bool, S_IRUGO | S_IWUSR);
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MODULE_PARM_DESC(debug, "Debug enabled or not");
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