usb: gadget: Gadget directory cleanup - group usb functions

The drivers/usb/gadget directory contains many files.
Files which are related can be distributed into separate directories.
This patch moves the USB functions implementations into a separate directory.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 0 insertions, 1347 deletions

diff --git a/drivers/usb/gadget/u_serial.c b/drivers/usb/gadget/u_serial.c
deleted file mode 100644
index ad0aca812002..000000000000
--- a/drivers/usb/gadget/u_serial.c
+++ /dev/null
@@ -1,1347 +0,0 @@
-/*
- * u_serial.c - utilities for USB gadget "serial port"/TTY support
- *
- * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
- * Copyright (C) 2008 David Brownell
- * Copyright (C) 2008 by Nokia Corporation
- *
- * This code also borrows from usbserial.c, which is
- * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
- * Copyright (C) 2000 Peter Berger (pberger@brimson.com)
- * Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com)
- *
- * This software is distributed under the terms of the GNU General
- * Public License ("GPL") as published by the Free Software Foundation,
- * either version 2 of that License or (at your option) any later version.
- */
-
-/* #define VERBOSE_DEBUG */
-
-#include <linux/kernel.h>
-#include <linux/sched.h>
-#include <linux/interrupt.h>
-#include <linux/device.h>
-#include <linux/delay.h>
-#include <linux/tty.h>
-#include <linux/tty_flip.h>
-#include <linux/slab.h>
-#include <linux/export.h>
-#include <linux/module.h>
-
-#include "u_serial.h"
-
-
-/*
- * This component encapsulates the TTY layer glue needed to provide basic
- * "serial port" functionality through the USB gadget stack.  Each such
- * port is exposed through a /dev/ttyGS* node.
- *
- * After this module has been loaded, the individual TTY port can be requested
- * (gserial_alloc_line()) and it will stay available until they are removed
- * (gserial_free_line()). Each one may be connected to a USB function
- * (gserial_connect), or disconnected (with gserial_disconnect) when the USB
- * host issues a config change event. Data can only flow when the port is
- * connected to the host.
- *
- * A given TTY port can be made available in multiple configurations.
- * For example, each one might expose a ttyGS0 node which provides a
- * login application.  In one case that might use CDC ACM interface 0,
- * while another configuration might use interface 3 for that.  The
- * work to handle that (including descriptor management) is not part
- * of this component.
- *
- * Configurations may expose more than one TTY port.  For example, if
- * ttyGS0 provides login service, then ttyGS1 might provide dialer access
- * for a telephone or fax link.  And ttyGS2 might be something that just
- * needs a simple byte stream interface for some messaging protocol that
- * is managed in userspace ... OBEX, PTP, and MTP have been mentioned.
- */
-
-#define PREFIX	"ttyGS"
-
-/*
- * gserial is the lifecycle interface, used by USB functions
- * gs_port is the I/O nexus, used by the tty driver
- * tty_struct links to the tty/filesystem framework
- *
- * gserial <---> gs_port ... links will be null when the USB link is
- * inactive; managed by gserial_{connect,disconnect}().  each gserial
- * instance can wrap its own USB control protocol.
- *	gserial->ioport == usb_ep->driver_data ... gs_port
- *	gs_port->port_usb ... gserial
- *
- * gs_port <---> tty_struct ... links will be null when the TTY file
- * isn't opened; managed by gs_open()/gs_close()
- *	gserial->port_tty ... tty_struct
- *	tty_struct->driver_data ... gserial
- */
-
-/* RX and TX queues can buffer QUEUE_SIZE packets before they hit the
- * next layer of buffering.  For TX that's a circular buffer; for RX
- * consider it a NOP.  A third layer is provided by the TTY code.
- */
-#define QUEUE_SIZE		16
-#define WRITE_BUF_SIZE		8192		/* TX only */
-
-/* circular buffer */
-struct gs_buf {
-	unsigned		buf_size;
-	char			*buf_buf;
-	char			*buf_get;
-	char			*buf_put;
-};
-
-/*
- * The port structure holds info for each port, one for each minor number
- * (and thus for each /dev/ node).
- */
-struct gs_port {
-	struct tty_port		port;
-	spinlock_t		port_lock;	/* guard port_* access */
-
-	struct gserial		*port_usb;
-
-	bool			openclose;	/* open/close in progress */
-	u8			port_num;
-
-	struct list_head	read_pool;
-	int read_started;
-	int read_allocated;
-	struct list_head	read_queue;
-	unsigned		n_read;
-	struct tasklet_struct	push;
-
-	struct list_head	write_pool;
-	int write_started;
-	int write_allocated;
-	struct gs_buf		port_write_buf;
-	wait_queue_head_t	drain_wait;	/* wait while writes drain */
-
-	/* REVISIT this state ... */
-	struct usb_cdc_line_coding port_line_coding;	/* 8-N-1 etc */
-};
-
-static struct portmaster {
-	struct mutex	lock;			/* protect open/close */
-	struct gs_port	*port;
-} ports[MAX_U_SERIAL_PORTS];
-
-#define GS_CLOSE_TIMEOUT		15		/* seconds */
-
-
-
-#ifdef VERBOSE_DEBUG
-#ifndef pr_vdebug
-#define pr_vdebug(fmt, arg...) \
-	pr_debug(fmt, ##arg)
-#endif /* pr_vdebug */
-#else
-#ifndef pr_vdebug
-#define pr_vdebug(fmt, arg...) \
-	({ if (0) pr_debug(fmt, ##arg); })
-#endif /* pr_vdebug */
-#endif
-
-/*-------------------------------------------------------------------------*/
-
-/* Circular Buffer */
-
-/*
- * gs_buf_alloc
- *
- * Allocate a circular buffer and all associated memory.
- */
-static int gs_buf_alloc(struct gs_buf *gb, unsigned size)
-{
-	gb->buf_buf = kmalloc(size, GFP_KERNEL);
-	if (gb->buf_buf == NULL)
-		return -ENOMEM;
-
-	gb->buf_size = size;
-	gb->buf_put = gb->buf_buf;
-	gb->buf_get = gb->buf_buf;
-
-	return 0;
-}
-
-/*
- * gs_buf_free
- *
- * Free the buffer and all associated memory.
- */
-static void gs_buf_free(struct gs_buf *gb)
-{
-	kfree(gb->buf_buf);
-	gb->buf_buf = NULL;
-}
-
-/*
- * gs_buf_clear
- *
- * Clear out all data in the circular buffer.
- */
-static void gs_buf_clear(struct gs_buf *gb)
-{
-	gb->buf_get = gb->buf_put;
-	/* equivalent to a get of all data available */
-}
-
-/*
- * gs_buf_data_avail
- *
- * Return the number of bytes of data written into the circular
- * buffer.
- */
-static unsigned gs_buf_data_avail(struct gs_buf *gb)
-{
-	return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size;
-}
-
-/*
- * gs_buf_space_avail
- *
- * Return the number of bytes of space available in the circular
- * buffer.
- */
-static unsigned gs_buf_space_avail(struct gs_buf *gb)
-{
-	return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size;
-}
-
-/*
- * gs_buf_put
- *
- * Copy data data from a user buffer and put it into the circular buffer.
- * Restrict to the amount of space available.
- *
- * Return the number of bytes copied.
- */
-static unsigned
-gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count)
-{
-	unsigned len;
-
-	len  = gs_buf_space_avail(gb);
-	if (count > len)
-		count = len;
-
-	if (count == 0)
-		return 0;
-
-	len = gb->buf_buf + gb->buf_size - gb->buf_put;
-	if (count > len) {
-		memcpy(gb->buf_put, buf, len);
-		memcpy(gb->buf_buf, buf+len, count - len);
-		gb->buf_put = gb->buf_buf + count - len;
-	} else {
-		memcpy(gb->buf_put, buf, count);
-		if (count < len)
-			gb->buf_put += count;
-		else /* count == len */
-			gb->buf_put = gb->buf_buf;
-	}
-
-	return count;
-}
-
-/*
- * gs_buf_get
- *
- * Get data from the circular buffer and copy to the given buffer.
- * Restrict to the amount of data available.
- *
- * Return the number of bytes copied.
- */
-static unsigned
-gs_buf_get(struct gs_buf *gb, char *buf, unsigned count)
-{
-	unsigned len;
-
-	len = gs_buf_data_avail(gb);
-	if (count > len)
-		count = len;
-
-	if (count == 0)
-		return 0;
-
-	len = gb->buf_buf + gb->buf_size - gb->buf_get;
-	if (count > len) {
-		memcpy(buf, gb->buf_get, len);
-		memcpy(buf+len, gb->buf_buf, count - len);
-		gb->buf_get = gb->buf_buf + count - len;
-	} else {
-		memcpy(buf, gb->buf_get, count);
-		if (count < len)
-			gb->buf_get += count;
-		else /* count == len */
-			gb->buf_get = gb->buf_buf;
-	}
-
-	return count;
-}
-
-/*-------------------------------------------------------------------------*/
-
-/* I/O glue between TTY (upper) and USB function (lower) driver layers */
-
-/*
- * gs_alloc_req
- *
- * Allocate a usb_request and its buffer.  Returns a pointer to the
- * usb_request or NULL if there is an error.
- */
-struct usb_request *
-gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags)
-{
-	struct usb_request *req;
-
-	req = usb_ep_alloc_request(ep, kmalloc_flags);
-
-	if (req != NULL) {
-		req->length = len;
-		req->buf = kmalloc(len, kmalloc_flags);
-		if (req->buf == NULL) {
-			usb_ep_free_request(ep, req);
-			return NULL;
-		}
-	}
-
-	return req;
-}
-EXPORT_SYMBOL_GPL(gs_alloc_req);
-
-/*
- * gs_free_req
- *
- * Free a usb_request and its buffer.
- */
-void gs_free_req(struct usb_ep *ep, struct usb_request *req)
-{
-	kfree(req->buf);
-	usb_ep_free_request(ep, req);
-}
-EXPORT_SYMBOL_GPL(gs_free_req);
-
-/*
- * gs_send_packet
- *
- * If there is data to send, a packet is built in the given
- * buffer and the size is returned.  If there is no data to
- * send, 0 is returned.
- *
- * Called with port_lock held.
- */
-static unsigned
-gs_send_packet(struct gs_port *port, char *packet, unsigned size)
-{
-	unsigned len;
-
-	len = gs_buf_data_avail(&port->port_write_buf);
-	if (len < size)
-		size = len;
-	if (size != 0)
-		size = gs_buf_get(&port->port_write_buf, packet, size);
-	return size;
-}
-
-/*
- * gs_start_tx
- *
- * This function finds available write requests, calls
- * gs_send_packet to fill these packets with data, and
- * continues until either there are no more write requests
- * available or no more data to send.  This function is
- * run whenever data arrives or write requests are available.
- *
- * Context: caller owns port_lock; port_usb is non-null.
- */
-static int gs_start_tx(struct gs_port *port)
-/*
-__releases(&port->port_lock)
-__acquires(&port->port_lock)
-*/
-{
-	struct list_head	*pool = &port->write_pool;
-	struct usb_ep		*in = port->port_usb->in;
-	int			status = 0;
-	bool			do_tty_wake = false;
-
-	while (!list_empty(pool)) {
-		struct usb_request	*req;
-		int			len;
-
-		if (port->write_started >= QUEUE_SIZE)
-			break;
-
-		req = list_entry(pool->next, struct usb_request, list);
-		len = gs_send_packet(port, req->buf, in->maxpacket);
-		if (len == 0) {
-			wake_up_interruptible(&port->drain_wait);
-			break;
-		}
-		do_tty_wake = true;
-
-		req->length = len;
-		list_del(&req->list);
-		req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0);
-
-		pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n",
-				port->port_num, len, *((u8 *)req->buf),
-				*((u8 *)req->buf+1), *((u8 *)req->buf+2));
-
-		/* Drop lock while we call out of driver; completions
-		 * could be issued while we do so.  Disconnection may
-		 * happen too; maybe immediately before we queue this!
-		 *
-		 * NOTE that we may keep sending data for a while after
-		 * the TTY closed (dev->ioport->port_tty is NULL).
-		 */
-		spin_unlock(&port->port_lock);
-		status = usb_ep_queue(in, req, GFP_ATOMIC);
-		spin_lock(&port->port_lock);
-
-		if (status) {
-			pr_debug("%s: %s %s err %d\n",
-					__func__, "queue", in->name, status);
-			list_add(&req->list, pool);
-			break;
-		}
-
-		port->write_started++;
-
-		/* abort immediately after disconnect */
-		if (!port->port_usb)
-			break;
-	}
-
-	if (do_tty_wake && port->port.tty)
-		tty_wakeup(port->port.tty);
-	return status;
-}
-
-/*
- * Context: caller owns port_lock, and port_usb is set
- */
-static unsigned gs_start_rx(struct gs_port *port)
-/*
-__releases(&port->port_lock)
-__acquires(&port->port_lock)
-*/
-{
-	struct list_head	*pool = &port->read_pool;
-	struct usb_ep		*out = port->port_usb->out;
-
-	while (!list_empty(pool)) {
-		struct usb_request	*req;
-		int			status;
-		struct tty_struct	*tty;
-
-		/* no more rx if closed */
-		tty = port->port.tty;
-		if (!tty)
-			break;
-
-		if (port->read_started >= QUEUE_SIZE)
-			break;
-
-		req = list_entry(pool->next, struct usb_request, list);
-		list_del(&req->list);
-		req->length = out->maxpacket;
-
-		/* drop lock while we call out; the controller driver
-		 * may need to call us back (e.g. for disconnect)
-		 */
-		spin_unlock(&port->port_lock);
-		status = usb_ep_queue(out, req, GFP_ATOMIC);
-		spin_lock(&port->port_lock);
-
-		if (status) {
-			pr_debug("%s: %s %s err %d\n",
-					__func__, "queue", out->name, status);
-			list_add(&req->list, pool);
-			break;
-		}
-		port->read_started++;
-
-		/* abort immediately after disconnect */
-		if (!port->port_usb)
-			break;
-	}
-	return port->read_started;
-}
-
-/*
- * RX tasklet takes data out of the RX queue and hands it up to the TTY
- * layer until it refuses to take any more data (or is throttled back).
- * Then it issues reads for any further data.
- *
- * If the RX queue becomes full enough that no usb_request is queued,
- * the OUT endpoint may begin NAKing as soon as its FIFO fills up.
- * So QUEUE_SIZE packets plus however many the FIFO holds (usually two)
- * can be buffered before the TTY layer's buffers (currently 64 KB).
- */
-static void gs_rx_push(unsigned long _port)
-{
-	struct gs_port		*port = (void *)_port;
-	struct tty_struct	*tty;
-	struct list_head	*queue = &port->read_queue;
-	bool			disconnect = false;
-	bool			do_push = false;
-
-	/* hand any queued data to the tty */
-	spin_lock_irq(&port->port_lock);
-	tty = port->port.tty;
-	while (!list_empty(queue)) {
-		struct usb_request	*req;
-
-		req = list_first_entry(queue, struct usb_request, list);
-
-		/* leave data queued if tty was rx throttled */
-		if (tty && test_bit(TTY_THROTTLED, &tty->flags))
-			break;
-
-		switch (req->status) {
-		case -ESHUTDOWN:
-			disconnect = true;
-			pr_vdebug(PREFIX "%d: shutdown\n", port->port_num);
-			break;
-
-		default:
-			/* presumably a transient fault */
-			pr_warning(PREFIX "%d: unexpected RX status %d\n",
-					port->port_num, req->status);
-			/* FALLTHROUGH */
-		case 0:
-			/* normal completion */
-			break;
-		}
-
-		/* push data to (open) tty */
-		if (req->actual) {
-			char		*packet = req->buf;
-			unsigned	size = req->actual;
-			unsigned	n;
-			int		count;
-
-			/* we may have pushed part of this packet already... */
-			n = port->n_read;
-			if (n) {
-				packet += n;
-				size -= n;
-			}
-
-			count = tty_insert_flip_string(&port->port, packet,
-					size);
-			if (count)
-				do_push = true;
-			if (count != size) {
-				/* stop pushing; TTY layer can't handle more */
-				port->n_read += count;
-				pr_vdebug(PREFIX "%d: rx block %d/%d\n",
-						port->port_num,
-						count, req->actual);
-				break;
-			}
-			port->n_read = 0;
-		}
-
-		list_move(&req->list, &port->read_pool);
-		port->read_started--;
-	}
-
-	/* Push from tty to ldisc; this is handled by a workqueue,
-	 * so we won't get callbacks and can hold port_lock
-	 */
-	if (do_push)
-		tty_flip_buffer_push(&port->port);
-
-
-	/* We want our data queue to become empty ASAP, keeping data
-	 * in the tty and ldisc (not here).  If we couldn't push any
-	 * this time around, there may be trouble unless there's an
-	 * implicit tty_unthrottle() call on its way...
-	 *
-	 * REVISIT we should probably add a timer to keep the tasklet
-	 * from starving ... but it's not clear that case ever happens.
-	 */
-	if (!list_empty(queue) && tty) {
-		if (!test_bit(TTY_THROTTLED, &tty->flags)) {
-			if (do_push)
-				tasklet_schedule(&port->push);
-			else
-				pr_warning(PREFIX "%d: RX not scheduled?\n",
-					port->port_num);
-		}
-	}
-
-	/* If we're still connected, refill the USB RX queue. */
-	if (!disconnect && port->port_usb)
-		gs_start_rx(port);
-
-	spin_unlock_irq(&port->port_lock);
-}
-
-static void gs_read_complete(struct usb_ep *ep, struct usb_request *req)
-{
-	struct gs_port	*port = ep->driver_data;
-
-	/* Queue all received data until the tty layer is ready for it. */
-	spin_lock(&port->port_lock);
-	list_add_tail(&req->list, &port->read_queue);
-	tasklet_schedule(&port->push);
-	spin_unlock(&port->port_lock);
-}
-
-static void gs_write_complete(struct usb_ep *ep, struct usb_request *req)
-{
-	struct gs_port	*port = ep->driver_data;
-
-	spin_lock(&port->port_lock);
-	list_add(&req->list, &port->write_pool);
-	port->write_started--;
-
-	switch (req->status) {
-	default:
-		/* presumably a transient fault */
-		pr_warning("%s: unexpected %s status %d\n",
-				__func__, ep->name, req->status);
-		/* FALL THROUGH */
-	case 0:
-		/* normal completion */
-		gs_start_tx(port);
-		break;
-
-	case -ESHUTDOWN:
-		/* disconnect */
-		pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
-		break;
-	}
-
-	spin_unlock(&port->port_lock);
-}
-
-static void gs_free_requests(struct usb_ep *ep, struct list_head *head,
-							 int *allocated)
-{
-	struct usb_request	*req;
-
-	while (!list_empty(head)) {
-		req = list_entry(head->next, struct usb_request, list);
-		list_del(&req->list);
-		gs_free_req(ep, req);
-		if (allocated)
-			(*allocated)--;
-	}
-}
-
-static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head,
-		void (*fn)(struct usb_ep *, struct usb_request *),
-		int *allocated)
-{
-	int			i;
-	struct usb_request	*req;
-	int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE;
-
-	/* Pre-allocate up to QUEUE_SIZE transfers, but if we can't
-	 * do quite that many this time, don't fail ... we just won't
-	 * be as speedy as we might otherwise be.
-	 */
-	for (i = 0; i < n; i++) {
-		req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC);
-		if (!req)
-			return list_empty(head) ? -ENOMEM : 0;
-		req->complete = fn;
-		list_add_tail(&req->list, head);
-		if (allocated)
-			(*allocated)++;
-	}
-	return 0;
-}
-
-/**
- * gs_start_io - start USB I/O streams
- * @dev: encapsulates endpoints to use
- * Context: holding port_lock; port_tty and port_usb are non-null
- *
- * We only start I/O when something is connected to both sides of
- * this port.  If nothing is listening on the host side, we may
- * be pointlessly filling up our TX buffers and FIFO.
- */
-static int gs_start_io(struct gs_port *port)
-{
-	struct list_head	*head = &port->read_pool;
-	struct usb_ep		*ep = port->port_usb->out;
-	int			status;
-	unsigned		started;
-
-	/* Allocate RX and TX I/O buffers.  We can't easily do this much
-	 * earlier (with GFP_KERNEL) because the requests are coupled to
-	 * endpoints, as are the packet sizes we'll be using.  Different
-	 * configurations may use different endpoints with a given port;
-	 * and high speed vs full speed changes packet sizes too.
-	 */
-	status = gs_alloc_requests(ep, head, gs_read_complete,
-		&port->read_allocated);
-	if (status)
-		return status;
-
-	status = gs_alloc_requests(port->port_usb->in, &port->write_pool,
-			gs_write_complete, &port->write_allocated);
-	if (status) {
-		gs_free_requests(ep, head, &port->read_allocated);
-		return status;
-	}
-
-	/* queue read requests */
-	port->n_read = 0;
-	started = gs_start_rx(port);
-
-	/* unblock any pending writes into our circular buffer */
-	if (started) {
-		tty_wakeup(port->port.tty);
-	} else {
-		gs_free_requests(ep, head, &port->read_allocated);
-		gs_free_requests(port->port_usb->in, &port->write_pool,
-			&port->write_allocated);
-		status = -EIO;
-	}
-
-	return status;
-}
-
-/*-------------------------------------------------------------------------*/
-
-/* TTY Driver */
-
-/*
- * gs_open sets up the link between a gs_port and its associated TTY.
- * That link is broken *only* by TTY close(), and all driver methods
- * know that.
- */
-static int gs_open(struct tty_struct *tty, struct file *file)
-{
-	int		port_num = tty->index;
-	struct gs_port	*port;
-	int		status;
-
-	do {
-		mutex_lock(&ports[port_num].lock);
-		port = ports[port_num].port;
-		if (!port)
-			status = -ENODEV;
-		else {
-			spin_lock_irq(&port->port_lock);
-
-			/* already open?  Great. */
-			if (port->port.count) {
-				status = 0;
-				port->port.count++;
-
-			/* currently opening/closing? wait ... */
-			} else if (port->openclose) {
-				status = -EBUSY;
-
-			/* ... else we do the work */
-			} else {
-				status = -EAGAIN;
-				port->openclose = true;
-			}
-			spin_unlock_irq(&port->port_lock);
-		}
-		mutex_unlock(&ports[port_num].lock);
-
-		switch (status) {
-		default:
-			/* fully handled */
-			return status;
-		case -EAGAIN:
-			/* must do the work */
-			break;
-		case -EBUSY:
-			/* wait for EAGAIN task to finish */
-			msleep(1);
-			/* REVISIT could have a waitchannel here, if
-			 * concurrent open performance is important
-			 */
-			break;
-		}
-	} while (status != -EAGAIN);
-
-	/* Do the "real open" */
-	spin_lock_irq(&port->port_lock);
-
-	/* allocate circular buffer on first open */
-	if (port->port_write_buf.buf_buf == NULL) {
-
-		spin_unlock_irq(&port->port_lock);
-		status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE);
-		spin_lock_irq(&port->port_lock);
-
-		if (status) {
-			pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n",
-				port->port_num, tty, file);
-			port->openclose = false;
-			goto exit_unlock_port;
-		}
-	}
-
-	/* REVISIT if REMOVED (ports[].port NULL), abort the open
-	 * to let rmmod work faster (but this way isn't wrong).
-	 */
-
-	/* REVISIT maybe wait for "carrier detect" */
-
-	tty->driver_data = port;
-	port->port.tty = tty;
-
-	port->port.count = 1;
-	port->openclose = false;
-
-	/* if connected, start the I/O stream */
-	if (port->port_usb) {
-		struct gserial	*gser = port->port_usb;
-
-		pr_debug("gs_open: start ttyGS%d\n", port->port_num);
-		gs_start_io(port);
-
-		if (gser->connect)
-			gser->connect(gser);
-	}
-
-	pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file);
-
-	status = 0;
-
-exit_unlock_port:
-	spin_unlock_irq(&port->port_lock);
-	return status;
-}
-
-static int gs_writes_finished(struct gs_port *p)
-{
-	int cond;
-
-	/* return true on disconnect or empty buffer */
-	spin_lock_irq(&p->port_lock);
-	cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf);
-	spin_unlock_irq(&p->port_lock);
-
-	return cond;
-}
-
-static void gs_close(struct tty_struct *tty, struct file *file)
-{
-	struct gs_port *port = tty->driver_data;
-	struct gserial	*gser;
-
-	spin_lock_irq(&port->port_lock);
-
-	if (port->port.count != 1) {
-		if (port->port.count == 0)
-			WARN_ON(1);
-		else
-			--port->port.count;
-		goto exit;
-	}
-
-	pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file);
-
-	/* mark port as closing but in use; we can drop port lock
-	 * and sleep if necessary
-	 */
-	port->openclose = true;
-	port->port.count = 0;
-
-	gser = port->port_usb;
-	if (gser && gser->disconnect)
-		gser->disconnect(gser);
-
-	/* wait for circular write buffer to drain, disconnect, or at
-	 * most GS_CLOSE_TIMEOUT seconds; then discard the rest
-	 */
-	if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) {
-		spin_unlock_irq(&port->port_lock);
-		wait_event_interruptible_timeout(port->drain_wait,
-					gs_writes_finished(port),
-					GS_CLOSE_TIMEOUT * HZ);
-		spin_lock_irq(&port->port_lock);
-		gser = port->port_usb;
-	}
-
-	/* Iff we're disconnected, there can be no I/O in flight so it's
-	 * ok to free the circular buffer; else just scrub it.  And don't
-	 * let the push tasklet fire again until we're re-opened.
-	 */
-	if (gser == NULL)
-		gs_buf_free(&port->port_write_buf);
-	else
-		gs_buf_clear(&port->port_write_buf);
-
-	tty->driver_data = NULL;
-	port->port.tty = NULL;
-
-	port->openclose = false;
-
-	pr_debug("gs_close: ttyGS%d (%p,%p) done!\n",
-			port->port_num, tty, file);
-
-	wake_up(&port->port.close_wait);
-exit:
-	spin_unlock_irq(&port->port_lock);
-}
-
-static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count)
-{
-	struct gs_port	*port = tty->driver_data;
-	unsigned long	flags;
-	int		status;
-
-	pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n",
-			port->port_num, tty, count);
-
-	spin_lock_irqsave(&port->port_lock, flags);
-	if (count)
-		count = gs_buf_put(&port->port_write_buf, buf, count);
-	/* treat count == 0 as flush_chars() */
-	if (port->port_usb)
-		status = gs_start_tx(port);
-	spin_unlock_irqrestore(&port->port_lock, flags);
-
-	return count;
-}
-
-static int gs_put_char(struct tty_struct *tty, unsigned char ch)
-{
-	struct gs_port	*port = tty->driver_data;
-	unsigned long	flags;
-	int		status;
-
-	pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %pf\n",
-		port->port_num, tty, ch, __builtin_return_address(0));
-
-	spin_lock_irqsave(&port->port_lock, flags);
-	status = gs_buf_put(&port->port_write_buf, &ch, 1);
-	spin_unlock_irqrestore(&port->port_lock, flags);
-
-	return status;
-}
-
-static void gs_flush_chars(struct tty_struct *tty)
-{
-	struct gs_port	*port = tty->driver_data;
-	unsigned long	flags;
-
-	pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty);
-
-	spin_lock_irqsave(&port->port_lock, flags);
-	if (port->port_usb)
-		gs_start_tx(port);
-	spin_unlock_irqrestore(&port->port_lock, flags);
-}
-
-static int gs_write_room(struct tty_struct *tty)
-{
-	struct gs_port	*port = tty->driver_data;
-	unsigned long	flags;
-	int		room = 0;
-
-	spin_lock_irqsave(&port->port_lock, flags);
-	if (port->port_usb)
-		room = gs_buf_space_avail(&port->port_write_buf);
-	spin_unlock_irqrestore(&port->port_lock, flags);
-
-	pr_vdebug("gs_write_room: (%d,%p) room=%d\n",
-		port->port_num, tty, room);
-
-	return room;
-}
-
-static int gs_chars_in_buffer(struct tty_struct *tty)
-{
-	struct gs_port	*port = tty->driver_data;
-	unsigned long	flags;
-	int		chars = 0;
-
-	spin_lock_irqsave(&port->port_lock, flags);
-	chars = gs_buf_data_avail(&port->port_write_buf);
-	spin_unlock_irqrestore(&port->port_lock, flags);
-
-	pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n",
-		port->port_num, tty, chars);
-
-	return chars;
-}
-
-/* undo side effects of setting TTY_THROTTLED */
-static void gs_unthrottle(struct tty_struct *tty)
-{
-	struct gs_port		*port = tty->driver_data;
-	unsigned long		flags;
-
-	spin_lock_irqsave(&port->port_lock, flags);
-	if (port->port_usb) {
-		/* Kickstart read queue processing.  We don't do xon/xoff,
-		 * rts/cts, or other handshaking with the host, but if the
-		 * read queue backs up enough we'll be NAKing OUT packets.
-		 */
-		tasklet_schedule(&port->push);
-		pr_vdebug(PREFIX "%d: unthrottle\n", port->port_num);
-	}
-	spin_unlock_irqrestore(&port->port_lock, flags);
-}
-
-static int gs_break_ctl(struct tty_struct *tty, int duration)
-{
-	struct gs_port	*port = tty->driver_data;
-	int		status = 0;
-	struct gserial	*gser;
-
-	pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n",
-			port->port_num, duration);
-
-	spin_lock_irq(&port->port_lock);
-	gser = port->port_usb;
-	if (gser && gser->send_break)
-		status = gser->send_break(gser, duration);
-	spin_unlock_irq(&port->port_lock);
-
-	return status;
-}
-
-static const struct tty_operations gs_tty_ops = {
-	.open =			gs_open,
-	.close =		gs_close,
-	.write =		gs_write,
-	.put_char =		gs_put_char,
-	.flush_chars =		gs_flush_chars,
-	.write_room =		gs_write_room,
-	.chars_in_buffer =	gs_chars_in_buffer,
-	.unthrottle =		gs_unthrottle,
-	.break_ctl =		gs_break_ctl,
-};
-
-/*-------------------------------------------------------------------------*/
-
-static struct tty_driver *gs_tty_driver;
-
-static int
-gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
-{
-	struct gs_port	*port;
-	int		ret = 0;
-
-	mutex_lock(&ports[port_num].lock);
-	if (ports[port_num].port) {
-		ret = -EBUSY;
-		goto out;
-	}
-
-	port = kzalloc(sizeof(struct gs_port), GFP_KERNEL);
-	if (port == NULL) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	tty_port_init(&port->port);
-	spin_lock_init(&port->port_lock);
-	init_waitqueue_head(&port->drain_wait);
-
-	tasklet_init(&port->push, gs_rx_push, (unsigned long) port);
-
-	INIT_LIST_HEAD(&port->read_pool);
-	INIT_LIST_HEAD(&port->read_queue);
-	INIT_LIST_HEAD(&port->write_pool);
-
-	port->port_num = port_num;
-	port->port_line_coding = *coding;
-
-	ports[port_num].port = port;
-out:
-	mutex_unlock(&ports[port_num].lock);
-	return ret;
-}
-
-static int gs_closed(struct gs_port *port)
-{
-	int cond;
-
-	spin_lock_irq(&port->port_lock);
-	cond = (port->port.count == 0) && !port->openclose;
-	spin_unlock_irq(&port->port_lock);
-	return cond;
-}
-
-static void gserial_free_port(struct gs_port *port)
-{
-	tasklet_kill(&port->push);
-	/* wait for old opens to finish */
-	wait_event(port->port.close_wait, gs_closed(port));
-	WARN_ON(port->port_usb != NULL);
-	tty_port_destroy(&port->port);
-	kfree(port);
-}
-
-void gserial_free_line(unsigned char port_num)
-{
-	struct gs_port	*port;
-
-	mutex_lock(&ports[port_num].lock);
-	if (WARN_ON(!ports[port_num].port)) {
-		mutex_unlock(&ports[port_num].lock);
-		return;
-	}
-	port = ports[port_num].port;
-	ports[port_num].port = NULL;
-	mutex_unlock(&ports[port_num].lock);
-
-	gserial_free_port(port);
-	tty_unregister_device(gs_tty_driver, port_num);
-}
-EXPORT_SYMBOL_GPL(gserial_free_line);
-
-int gserial_alloc_line(unsigned char *line_num)
-{
-	struct usb_cdc_line_coding	coding;
-	struct device			*tty_dev;
-	int				ret;
-	int				port_num;
-
-	coding.dwDTERate = cpu_to_le32(9600);
-	coding.bCharFormat = 8;
-	coding.bParityType = USB_CDC_NO_PARITY;
-	coding.bDataBits = USB_CDC_1_STOP_BITS;
-
-	for (port_num = 0; port_num < MAX_U_SERIAL_PORTS; port_num++) {
-		ret = gs_port_alloc(port_num, &coding);
-		if (ret == -EBUSY)
-			continue;
-		if (ret)
-			return ret;
-		break;
-	}
-	if (ret)
-		return ret;
-
-	/* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
-
-	tty_dev = tty_port_register_device(&ports[port_num].port->port,
-			gs_tty_driver, port_num, NULL);
-	if (IS_ERR(tty_dev)) {
-		struct gs_port	*port;
-		pr_err("%s: failed to register tty for port %d, err %ld\n",
-				__func__, port_num, PTR_ERR(tty_dev));
-
-		ret = PTR_ERR(tty_dev);
-		port = ports[port_num].port;
-		ports[port_num].port = NULL;
-		gserial_free_port(port);
-		goto err;
-	}
-	*line_num = port_num;
-err:
-	return ret;
-}
-EXPORT_SYMBOL_GPL(gserial_alloc_line);
-
-/**
- * gserial_connect - notify TTY I/O glue that USB link is active
- * @gser: the function, set up with endpoints and descriptors
- * @port_num: which port is active
- * Context: any (usually from irq)
- *
- * This is called activate endpoints and let the TTY layer know that
- * the connection is active ... not unlike "carrier detect".  It won't
- * necessarily start I/O queues; unless the TTY is held open by any
- * task, there would be no point.  However, the endpoints will be
- * activated so the USB host can perform I/O, subject to basic USB
- * hardware flow control.
- *
- * Caller needs to have set up the endpoints and USB function in @dev
- * before calling this, as well as the appropriate (speed-specific)
- * endpoint descriptors, and also have allocate @port_num by calling
- * @gserial_alloc_line().
- *
- * Returns negative errno or zero.
- * On success, ep->driver_data will be overwritten.
- */
-int gserial_connect(struct gserial *gser, u8 port_num)
-{
-	struct gs_port	*port;
-	unsigned long	flags;
-	int		status;
-
-	if (port_num >= MAX_U_SERIAL_PORTS)
-		return -ENXIO;
-
-	port = ports[port_num].port;
-	if (!port) {
-		pr_err("serial line %d not allocated.\n", port_num);
-		return -EINVAL;
-	}
-	if (port->port_usb) {
-		pr_err("serial line %d is in use.\n", port_num);
-		return -EBUSY;
-	}
-
-	/* activate the endpoints */
-	status = usb_ep_enable(gser->in);
-	if (status < 0)
-		return status;
-	gser->in->driver_data = port;
-
-	status = usb_ep_enable(gser->out);
-	if (status < 0)
-		goto fail_out;
-	gser->out->driver_data = port;
-
-	/* then tell the tty glue that I/O can work */
-	spin_lock_irqsave(&port->port_lock, flags);
-	gser->ioport = port;
-	port->port_usb = gser;
-
-	/* REVISIT unclear how best to handle this state...
-	 * we don't really couple it with the Linux TTY.
-	 */
-	gser->port_line_coding = port->port_line_coding;
-
-	/* REVISIT if waiting on "carrier detect", signal. */
-
-	/* if it's already open, start I/O ... and notify the serial
-	 * protocol about open/close status (connect/disconnect).
-	 */
-	if (port->port.count) {
-		pr_debug("gserial_connect: start ttyGS%d\n", port->port_num);
-		gs_start_io(port);
-		if (gser->connect)
-			gser->connect(gser);
-	} else {
-		if (gser->disconnect)
-			gser->disconnect(gser);
-	}
-
-	spin_unlock_irqrestore(&port->port_lock, flags);
-
-	return status;
-
-fail_out:
-	usb_ep_disable(gser->in);
-	gser->in->driver_data = NULL;
-	return status;
-}
-EXPORT_SYMBOL_GPL(gserial_connect);
-/**
- * gserial_disconnect - notify TTY I/O glue that USB link is inactive
- * @gser: the function, on which gserial_connect() was called
- * Context: any (usually from irq)
- *
- * This is called to deactivate endpoints and let the TTY layer know
- * that the connection went inactive ... not unlike "hangup".
- *
- * On return, the state is as if gserial_connect() had never been called;
- * there is no active USB I/O on these endpoints.
- */
-void gserial_disconnect(struct gserial *gser)
-{
-	struct gs_port	*port = gser->ioport;
-	unsigned long	flags;
-
-	if (!port)
-		return;
-
-	/* tell the TTY glue not to do I/O here any more */
-	spin_lock_irqsave(&port->port_lock, flags);
-
-	/* REVISIT as above: how best to track this? */
-	port->port_line_coding = gser->port_line_coding;
-
-	port->port_usb = NULL;
-	gser->ioport = NULL;
-	if (port->port.count > 0 || port->openclose) {
-		wake_up_interruptible(&port->drain_wait);
-		if (port->port.tty)
-			tty_hangup(port->port.tty);
-	}
-	spin_unlock_irqrestore(&port->port_lock, flags);
-
-	/* disable endpoints, aborting down any active I/O */
-	usb_ep_disable(gser->out);
-	gser->out->driver_data = NULL;
-
-	usb_ep_disable(gser->in);
-	gser->in->driver_data = NULL;
-
-	/* finally, free any unused/unusable I/O buffers */
-	spin_lock_irqsave(&port->port_lock, flags);
-	if (port->port.count == 0 && !port->openclose)
-		gs_buf_free(&port->port_write_buf);
-	gs_free_requests(gser->out, &port->read_pool, NULL);
-	gs_free_requests(gser->out, &port->read_queue, NULL);
-	gs_free_requests(gser->in, &port->write_pool, NULL);
-
-	port->read_allocated = port->read_started =
-		port->write_allocated = port->write_started = 0;
-
-	spin_unlock_irqrestore(&port->port_lock, flags);
-}
-EXPORT_SYMBOL_GPL(gserial_disconnect);
-
-static int userial_init(void)
-{
-	unsigned			i;
-	int				status;
-
-	gs_tty_driver = alloc_tty_driver(MAX_U_SERIAL_PORTS);
-	if (!gs_tty_driver)
-		return -ENOMEM;
-
-	gs_tty_driver->driver_name = "g_serial";
-	gs_tty_driver->name = PREFIX;
-	/* uses dynamically assigned dev_t values */
-
-	gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
-	gs_tty_driver->subtype = SERIAL_TYPE_NORMAL;
-	gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
-	gs_tty_driver->init_termios = tty_std_termios;
-
-	/* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on
-	 * MS-Windows.  Otherwise, most of these flags shouldn't affect
-	 * anything unless we were to actually hook up to a serial line.
-	 */
-	gs_tty_driver->init_termios.c_cflag =
-			B9600 | CS8 | CREAD | HUPCL | CLOCAL;
-	gs_tty_driver->init_termios.c_ispeed = 9600;
-	gs_tty_driver->init_termios.c_ospeed = 9600;
-
-	tty_set_operations(gs_tty_driver, &gs_tty_ops);
-	for (i = 0; i < MAX_U_SERIAL_PORTS; i++)
-		mutex_init(&ports[i].lock);
-
-	/* export the driver ... */
-	status = tty_register_driver(gs_tty_driver);
-	if (status) {
-		pr_err("%s: cannot register, err %d\n",
-				__func__, status);
-		goto fail;
-	}
-
-	pr_debug("%s: registered %d ttyGS* device%s\n", __func__,
-			MAX_U_SERIAL_PORTS,
-			(MAX_U_SERIAL_PORTS == 1) ? "" : "s");
-
-	return status;
-fail:
-	put_tty_driver(gs_tty_driver);
-	gs_tty_driver = NULL;
-	return status;
-}
-module_init(userial_init);
-
-static void userial_cleanup(void)
-{
-	tty_unregister_driver(gs_tty_driver);
-	put_tty_driver(gs_tty_driver);
-	gs_tty_driver = NULL;
-}
-module_exit(userial_cleanup);
-
-MODULE_LICENSE("GPL");