Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 839 insertions, 0 deletions

diff --git a/drivers/usb/misc/uss720.c b/drivers/usb/misc/uss720.c
new file mode 100644
index 000000000..bd0ad7c32
--- /dev/null
+++ b/drivers/usb/misc/uss720.c
@@ -0,0 +1,839 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*****************************************************************************/
+
+/*
+ *	uss720.c  --  USS720 USB Parport Cable.
+ *
+ *	Copyright (C) 1999, 2005, 2010
+ *	    Thomas Sailer (t.sailer@alumni.ethz.ch)
+ *
+ *  Based on parport_pc.c
+ *
+ *  History:
+ *   0.1  04.08.1999  Created
+ *   0.2  07.08.1999  Some fixes mainly suggested by Tim Waugh
+ *		      Interrupt handling currently disabled because
+ *		      usb_request_irq crashes somewhere within ohci.c
+ *		      for no apparent reason (that is for me, anyway)
+ *		      ECP currently untested
+ *   0.3  10.08.1999  fixing merge errors
+ *   0.4  13.08.1999  Added Vendor/Product ID of Brad Hard's cable
+ *   0.5  20.09.1999  usb_control_msg wrapper used
+ *        Nov01.2000  usb_device_table support by Adam J. Richter
+ *        08.04.2001  Identify version on module load.  gb
+ *   0.6  02.09.2005  Fix "scheduling in interrupt" problem by making save/restore
+ *                    context asynchronous
+ *
+ */
+
+/*****************************************************************************/
+
+#include <linux/module.h>
+#include <linux/socket.h>
+#include <linux/parport.h>
+#include <linux/init.h>
+#include <linux/usb.h>
+#include <linux/delay.h>
+#include <linux/completion.h>
+#include <linux/kref.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+
+#define DRIVER_AUTHOR "Thomas M. Sailer, t.sailer@alumni.ethz.ch"
+#define DRIVER_DESC "USB Parport Cable driver for Cables using the Lucent Technologies USS720 Chip"
+
+/* --------------------------------------------------------------------- */
+
+struct parport_uss720_private {
+	struct usb_device *usbdev;
+	struct parport *pp;
+	struct kref ref_count;
+	__u8 reg[7];  /* USB registers */
+	struct list_head asynclist;
+	spinlock_t asynclock;
+};
+
+struct uss720_async_request {
+	struct parport_uss720_private *priv;
+	struct kref ref_count;
+	struct list_head asynclist;
+	struct completion compl;
+	struct urb *urb;
+	struct usb_ctrlrequest *dr;
+	__u8 reg[7];
+};
+
+/* --------------------------------------------------------------------- */
+
+static void destroy_priv(struct kref *kref)
+{
+	struct parport_uss720_private *priv = container_of(kref, struct parport_uss720_private, ref_count);
+
+	dev_dbg(&priv->usbdev->dev, "destroying priv datastructure\n");
+	usb_put_dev(priv->usbdev);
+	priv->usbdev = NULL;
+	kfree(priv);
+}
+
+static void destroy_async(struct kref *kref)
+{
+	struct uss720_async_request *rq = container_of(kref, struct uss720_async_request, ref_count);
+	struct parport_uss720_private *priv = rq->priv;
+	unsigned long flags;
+
+	if (likely(rq->urb))
+		usb_free_urb(rq->urb);
+	kfree(rq->dr);
+	spin_lock_irqsave(&priv->asynclock, flags);
+	list_del_init(&rq->asynclist);
+	spin_unlock_irqrestore(&priv->asynclock, flags);
+	kfree(rq);
+	kref_put(&priv->ref_count, destroy_priv);
+}
+
+/* --------------------------------------------------------------------- */
+
+static void async_complete(struct urb *urb)
+{
+	struct uss720_async_request *rq;
+	struct parport *pp;
+	struct parport_uss720_private *priv;
+	int status = urb->status;
+
+	rq = urb->context;
+	priv = rq->priv;
+	pp = priv->pp;
+	if (status) {
+		dev_err(&urb->dev->dev, "async_complete: urb error %d\n",
+			status);
+	} else if (rq->dr->bRequest == 3) {
+		memcpy(priv->reg, rq->reg, sizeof(priv->reg));
+#if 0
+		dev_dbg(&priv->usbdev->dev, "async_complete regs %7ph\n",
+			priv->reg);
+#endif
+		/* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
+		if (rq->reg[2] & rq->reg[1] & 0x10 && pp)
+			parport_generic_irq(pp);
+	}
+	complete(&rq->compl);
+	kref_put(&rq->ref_count, destroy_async);
+}
+
+static struct uss720_async_request *submit_async_request(struct parport_uss720_private *priv,
+							 __u8 request, __u8 requesttype, __u16 value, __u16 index,
+							 gfp_t mem_flags)
+{
+	struct usb_device *usbdev;
+	struct uss720_async_request *rq;
+	unsigned long flags;
+	int ret;
+
+	if (!priv)
+		return NULL;
+	usbdev = priv->usbdev;
+	if (!usbdev)
+		return NULL;
+	rq = kzalloc_obj(struct uss720_async_request, mem_flags);
+	if (!rq)
+		return NULL;
+	kref_init(&rq->ref_count);
+	INIT_LIST_HEAD(&rq->asynclist);
+	init_completion(&rq->compl);
+	kref_get(&priv->ref_count);
+	rq->priv = priv;
+	rq->urb = usb_alloc_urb(0, mem_flags);
+	if (!rq->urb) {
+		kref_put(&rq->ref_count, destroy_async);
+		return NULL;
+	}
+	rq->dr = kmalloc_obj(*rq->dr, mem_flags);
+	if (!rq->dr) {
+		kref_put(&rq->ref_count, destroy_async);
+		return NULL;
+	}
+	rq->dr->bRequestType = requesttype;
+	rq->dr->bRequest = request;
+	rq->dr->wValue = cpu_to_le16(value);
+	rq->dr->wIndex = cpu_to_le16(index);
+	rq->dr->wLength = cpu_to_le16((request == 3) ? sizeof(rq->reg) : 0);
+	usb_fill_control_urb(rq->urb, usbdev, (requesttype & 0x80) ? usb_rcvctrlpipe(usbdev, 0) : usb_sndctrlpipe(usbdev, 0),
+			     (unsigned char *)rq->dr,
+			     (request == 3) ? rq->reg : NULL, (request == 3) ? sizeof(rq->reg) : 0, async_complete, rq);
+	/* rq->urb->transfer_flags |= URB_ASYNC_UNLINK; */
+	spin_lock_irqsave(&priv->asynclock, flags);
+	list_add_tail(&rq->asynclist, &priv->asynclist);
+	spin_unlock_irqrestore(&priv->asynclock, flags);
+	kref_get(&rq->ref_count);
+	ret = usb_submit_urb(rq->urb, mem_flags);
+	if (!ret)
+		return rq;
+	destroy_async(&rq->ref_count);
+	dev_err(&usbdev->dev, "submit_async_request submit_urb failed with %d\n", ret);
+	return NULL;
+}
+
+static unsigned int kill_all_async_requests_priv(struct parport_uss720_private *priv)
+{
+	struct uss720_async_request *rq;
+	unsigned long flags;
+	unsigned int ret = 0;
+
+	spin_lock_irqsave(&priv->asynclock, flags);
+	list_for_each_entry(rq, &priv->asynclist, asynclist) {
+		usb_unlink_urb(rq->urb);
+		ret++;
+	}
+	spin_unlock_irqrestore(&priv->asynclock, flags);
+	return ret;
+}
+
+/* --------------------------------------------------------------------- */
+
+static int get_1284_register(struct parport *pp, unsigned char reg, unsigned char *val, gfp_t mem_flags)
+{
+	struct parport_uss720_private *priv;
+	struct uss720_async_request *rq;
+	static const unsigned char regindex[9] = {
+		4, 0, 1, 5, 5, 0, 2, 3, 6
+	};
+	int ret;
+
+	if (!pp)
+		return -EIO;
+	priv = pp->private_data;
+	rq = submit_async_request(priv, 3, 0xc0, ((unsigned int)reg) << 8, 0, mem_flags);
+	if (!rq) {
+		dev_err(&priv->usbdev->dev, "get_1284_register(%u) failed",
+			(unsigned int)reg);
+		return -EIO;
+	}
+	if (!val) {
+		kref_put(&rq->ref_count, destroy_async);
+		return 0;
+	}
+	if (wait_for_completion_timeout(&rq->compl, HZ)) {
+		ret = rq->urb->status;
+		*val = priv->reg[(reg >= 9) ? 0 : regindex[reg]];
+		if (ret)
+			printk(KERN_WARNING "get_1284_register: "
+			       "usb error %d\n", ret);
+		kref_put(&rq->ref_count, destroy_async);
+		return ret;
+	}
+	printk(KERN_WARNING "get_1284_register timeout\n");
+	kill_all_async_requests_priv(priv);
+	kref_put(&rq->ref_count, destroy_async);
+	return -EIO;
+}
+
+static int set_1284_register(struct parport *pp, unsigned char reg, unsigned char val, gfp_t mem_flags)
+{
+	struct parport_uss720_private *priv;
+	struct uss720_async_request *rq;
+
+	if (!pp)
+		return -EIO;
+	priv = pp->private_data;
+	rq = submit_async_request(priv, 4, 0x40, (((unsigned int)reg) << 8) | val, 0, mem_flags);
+	if (!rq) {
+		dev_err(&priv->usbdev->dev, "set_1284_register(%u,%u) failed",
+			(unsigned int)reg, (unsigned int)val);
+		return -EIO;
+	}
+	kref_put(&rq->ref_count, destroy_async);
+	return 0;
+}
+
+/* --------------------------------------------------------------------- */
+
+/* ECR modes */
+#define ECR_SPP 00
+#define ECR_PS2 01
+#define ECR_PPF 02
+#define ECR_ECP 03
+#define ECR_EPP 04
+
+/* Safely change the mode bits in the ECR */
+static int change_mode(struct parport *pp, int m)
+{
+	struct parport_uss720_private *priv = pp->private_data;
+	int mode;
+	__u8 reg;
+
+	if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
+		return -EIO;
+	/* Bits <7:5> contain the mode. */
+	mode = (priv->reg[2] >> 5) & 0x7;
+	if (mode == m)
+		return 0;
+	/* We have to go through mode 000 or 001 */
+	if (mode > ECR_PS2 && m > ECR_PS2)
+		if (change_mode(pp, ECR_PS2))
+			return -EIO;
+
+	if (m <= ECR_PS2 && !(priv->reg[1] & 0x20)) {
+		/* This mode resets the FIFO, so we may
+		 * have to wait for it to drain first. */
+		unsigned long expire = jiffies + pp->physport->cad->timeout;
+		switch (mode) {
+		case ECR_PPF: /* Parallel Port FIFO mode */
+		case ECR_ECP: /* ECP Parallel Port mode */
+			/* Poll slowly. */
+			for (;;) {
+				if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
+					return -EIO;
+				if (priv->reg[2] & 0x01)
+					break;
+				if (time_after_eq (jiffies, expire))
+					/* The FIFO is stuck. */
+					return -EBUSY;
+				msleep_interruptible(10);
+				if (signal_pending (current))
+					break;
+			}
+		}
+	}
+	/* Set the mode. */
+	if (set_1284_register(pp, 6, m << 5, GFP_KERNEL))
+		return -EIO;
+	if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
+		return -EIO;
+	return 0;
+}
+
+/*
+ * Clear TIMEOUT BIT in EPP MODE
+ */
+static int clear_epp_timeout(struct parport *pp)
+{
+	unsigned char stat;
+
+	if (get_1284_register(pp, 1, &stat, GFP_KERNEL))
+		return 1;
+	return stat & 1;
+}
+
+/*
+ * Access functions.
+ */
+#if 0
+static int uss720_irq(int usbstatus, void *buffer, int len, void *dev_id)
+{
+	struct parport *pp = (struct parport *)dev_id;
+	struct parport_uss720_private *priv = pp->private_data;	
+
+	if (usbstatus != 0 || len < 4 || !buffer)
+		return 1;
+	memcpy(priv->reg, buffer, 4);
+	/* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
+	if (priv->reg[2] & priv->reg[1] & 0x10)
+		parport_generic_irq(pp);
+	return 1;
+}
+#endif
+
+static void parport_uss720_write_data(struct parport *pp, unsigned char d)
+{
+	set_1284_register(pp, 0, d, GFP_KERNEL);
+}
+
+static unsigned char parport_uss720_read_data(struct parport *pp)
+{
+	unsigned char ret;
+
+	if (get_1284_register(pp, 0, &ret, GFP_KERNEL))
+		return 0;
+	return ret;
+}
+
+static void parport_uss720_write_control(struct parport *pp, unsigned char d)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+
+	d = (d & 0xf) | (priv->reg[1] & 0xf0);
+	if (set_1284_register(pp, 2, d, GFP_KERNEL))
+		return;
+	priv->reg[1] = d;
+}
+
+static unsigned char parport_uss720_read_control(struct parport *pp)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	return priv->reg[1] & 0xf; /* Use soft copy */
+}
+
+static unsigned char parport_uss720_frob_control(struct parport *pp, unsigned char mask, unsigned char val)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	unsigned char d;
+
+	mask &= 0x0f;
+	val &= 0x0f;
+	d = (priv->reg[1] & (~mask)) ^ val;
+	if (set_1284_register(pp, 2, d, GFP_ATOMIC))
+		return 0;
+	priv->reg[1] = d;
+	return d & 0xf;
+}
+
+static unsigned char parport_uss720_read_status(struct parport *pp)
+{
+	unsigned char ret;
+
+	if (get_1284_register(pp, 1, &ret, GFP_ATOMIC))
+		return 0;
+	return ret & 0xf8;
+}
+
+static void parport_uss720_disable_irq(struct parport *pp)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	unsigned char d;
+
+	d = priv->reg[1] & ~0x10;
+	if (set_1284_register(pp, 2, d, GFP_KERNEL))
+		return;
+	priv->reg[1] = d;
+}
+
+static void parport_uss720_enable_irq(struct parport *pp)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	unsigned char d;
+
+	d = priv->reg[1] | 0x10;
+	if (set_1284_register(pp, 2, d, GFP_KERNEL))
+		return;
+	priv->reg[1] = d;
+}
+
+static void parport_uss720_data_forward (struct parport *pp)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	unsigned char d;
+
+	d = priv->reg[1] & ~0x20;
+	if (set_1284_register(pp, 2, d, GFP_KERNEL))
+		return;
+	priv->reg[1] = d;
+}
+
+static void parport_uss720_data_reverse (struct parport *pp)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	unsigned char d;
+
+	d = priv->reg[1] | 0x20;
+	if (set_1284_register(pp, 2, d, GFP_KERNEL))
+		return;
+	priv->reg[1] = d;
+}
+
+static void parport_uss720_init_state(struct pardevice *dev, struct parport_state *s)
+{
+	s->u.pc.ctr = 0xc | (dev->irq_func ? 0x10 : 0x0);
+	s->u.pc.ecr = 0x24;
+}
+
+static void parport_uss720_save_state(struct parport *pp, struct parport_state *s)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+
+#if 0
+	if (get_1284_register(pp, 2, NULL, GFP_ATOMIC))
+		return;
+#endif
+	s->u.pc.ctr = priv->reg[1];
+	s->u.pc.ecr = priv->reg[2];
+}
+
+static void parport_uss720_restore_state(struct parport *pp, struct parport_state *s)
+{
+	struct parport_uss720_private *priv = pp->private_data;
+
+	set_1284_register(pp, 2, s->u.pc.ctr, GFP_ATOMIC);
+	set_1284_register(pp, 6, s->u.pc.ecr, GFP_ATOMIC);
+	get_1284_register(pp, 2, NULL, GFP_ATOMIC);
+	priv->reg[1] = s->u.pc.ctr;
+	priv->reg[2] = s->u.pc.ecr;
+}
+
+static size_t parport_uss720_epp_read_data(struct parport *pp, void *buf, size_t length, int flags)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	size_t got = 0;
+
+	if (change_mode(pp, ECR_EPP))
+		return 0;
+	for (; got < length; got++) {
+		if (get_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
+			break;
+		buf++;
+		if (priv->reg[0] & 0x01) {
+			clear_epp_timeout(pp);
+			break;
+		}
+	}
+	change_mode(pp, ECR_PS2);
+	return got;
+}
+
+static size_t parport_uss720_epp_write_data(struct parport *pp, const void *buf, size_t length, int flags)
+{
+#if 0
+	struct parport_uss720_private *priv = pp->private_data;	
+	size_t written = 0;
+
+	if (change_mode(pp, ECR_EPP))
+		return 0;
+	for (; written < length; written++) {
+		if (set_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
+			break;
+		((char*)buf)++;
+		if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
+			break;
+		if (priv->reg[0] & 0x01) {
+			clear_epp_timeout(pp);
+			break;
+		}
+	}
+	change_mode(pp, ECR_PS2);
+	return written;
+#else
+	struct parport_uss720_private *priv = pp->private_data;
+	struct usb_device *usbdev = priv->usbdev;
+	int rlen = 0;
+	int i;
+
+	if (!usbdev)
+		return 0;
+	if (change_mode(pp, ECR_EPP))
+		return 0;
+	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buf, length, &rlen, 20000);
+	if (i)
+		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %zu rlen %u\n", buf, length, rlen);
+	change_mode(pp, ECR_PS2);
+	return rlen;
+#endif
+}
+
+static size_t parport_uss720_epp_read_addr(struct parport *pp, void *buf, size_t length, int flags)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	size_t got = 0;
+
+	if (change_mode(pp, ECR_EPP))
+		return 0;
+	for (; got < length; got++) {
+		if (get_1284_register(pp, 3, (char *)buf, GFP_KERNEL))
+			break;
+		buf++;
+		if (priv->reg[0] & 0x01) {
+			clear_epp_timeout(pp);
+			break;
+		}
+	}
+	change_mode(pp, ECR_PS2);
+	return got;
+}
+
+static size_t parport_uss720_epp_write_addr(struct parport *pp, const void *buf, size_t length, int flags)
+{
+	struct parport_uss720_private *priv = pp->private_data;	
+	size_t written = 0;
+
+	if (change_mode(pp, ECR_EPP))
+		return 0;
+	for (; written < length; written++) {
+		if (set_1284_register(pp, 3, *(char *)buf, GFP_KERNEL))
+			break;
+		buf++;
+		if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
+			break;
+		if (priv->reg[0] & 0x01) {
+			clear_epp_timeout(pp);
+			break;
+		}
+	}
+	change_mode(pp, ECR_PS2);
+	return written;
+}
+
+static size_t parport_uss720_ecp_write_data(struct parport *pp, const void *buffer, size_t len, int flags)
+{
+	struct parport_uss720_private *priv = pp->private_data;
+	struct usb_device *usbdev = priv->usbdev;
+	int rlen = 0;
+	int i;
+
+	if (!usbdev)
+		return 0;
+	if (change_mode(pp, ECR_ECP))
+		return 0;
+	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buffer, len, &rlen, 20000);
+	if (i)
+		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %zu rlen %u\n", buffer, len, rlen);
+	change_mode(pp, ECR_PS2);
+	return rlen;
+}
+
+static size_t parport_uss720_ecp_read_data(struct parport *pp, void *buffer, size_t len, int flags)
+{
+	struct parport_uss720_private *priv = pp->private_data;
+	struct usb_device *usbdev = priv->usbdev;
+	int rlen = 0;
+	int i;
+
+	if (!usbdev)
+		return 0;
+	if (change_mode(pp, ECR_ECP))
+		return 0;
+	i = usb_bulk_msg(usbdev, usb_rcvbulkpipe(usbdev, 2), buffer, len, &rlen, 20000);
+	if (i)
+		printk(KERN_ERR "uss720: recvbulk ep 2 buf %p len %zu rlen %u\n", buffer, len, rlen);
+	change_mode(pp, ECR_PS2);
+	return rlen;
+}
+
+static size_t parport_uss720_ecp_write_addr(struct parport *pp, const void *buffer, size_t len, int flags)
+{
+	size_t written = 0;
+
+	if (change_mode(pp, ECR_ECP))
+		return 0;
+	for (; written < len; written++) {
+		if (set_1284_register(pp, 5, *(char *)buffer, GFP_KERNEL))
+			break;
+		buffer++;
+	}
+	change_mode(pp, ECR_PS2);
+	return written;
+}
+
+static size_t parport_uss720_write_compat(struct parport *pp, const void *buffer, size_t len, int flags)
+{
+	struct parport_uss720_private *priv = pp->private_data;
+	struct usb_device *usbdev = priv->usbdev;
+	int rlen = 0;
+	int i;
+
+	if (!usbdev)
+		return 0;
+	if (change_mode(pp, ECR_PPF))
+		return 0;
+	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buffer, len, &rlen, 20000);
+	if (i)
+		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %zu rlen %u\n", buffer, len, rlen);
+	change_mode(pp, ECR_PS2);
+	return rlen;
+}
+
+/* --------------------------------------------------------------------- */
+
+static struct parport_operations parport_uss720_ops = 
+{
+	.owner =		THIS_MODULE,
+	.write_data =		parport_uss720_write_data,
+	.read_data =		parport_uss720_read_data,
+
+	.write_control =	parport_uss720_write_control,
+	.read_control =		parport_uss720_read_control,
+	.frob_control =		parport_uss720_frob_control,
+
+	.read_status =		parport_uss720_read_status,
+
+	.enable_irq =		parport_uss720_enable_irq,
+	.disable_irq =		parport_uss720_disable_irq,
+
+	.data_forward =		parport_uss720_data_forward,
+	.data_reverse =		parport_uss720_data_reverse,
+
+	.init_state =		parport_uss720_init_state,
+	.save_state =		parport_uss720_save_state,
+	.restore_state =	parport_uss720_restore_state,
+
+	.epp_write_data =	parport_uss720_epp_write_data,
+	.epp_read_data =	parport_uss720_epp_read_data,
+	.epp_write_addr =	parport_uss720_epp_write_addr,
+	.epp_read_addr =	parport_uss720_epp_read_addr,
+
+	.ecp_write_data =	parport_uss720_ecp_write_data,
+	.ecp_read_data =	parport_uss720_ecp_read_data,
+	.ecp_write_addr =	parport_uss720_ecp_write_addr,
+
+	.compat_write_data =	parport_uss720_write_compat,
+	.nibble_read_data =	parport_ieee1284_read_nibble,
+	.byte_read_data =	parport_ieee1284_read_byte,
+};
+
+/* --------------------------------------------------------------------- */
+
+static int uss720_probe(struct usb_interface *intf,
+			const struct usb_device_id *id)
+{
+	struct usb_device *usbdev = usb_get_dev(interface_to_usbdev(intf));
+	struct usb_host_interface *interface;
+	struct usb_endpoint_descriptor *epd;
+	struct parport_uss720_private *priv;
+	struct parport *pp;
+	unsigned char reg;
+	int ret = -ENODEV;
+
+	dev_dbg(&intf->dev, "probe: vendor id 0x%x, device id 0x%x\n",
+		le16_to_cpu(usbdev->descriptor.idVendor),
+		le16_to_cpu(usbdev->descriptor.idProduct));
+
+	/* our known interfaces have 3 alternate settings */
+	if (intf->num_altsetting != 3)
+		goto bail_out_early;
+
+	ret = usb_set_interface(usbdev, intf->altsetting->desc.bInterfaceNumber, 2);
+	dev_dbg(&intf->dev, "set interface result %d\n", ret);
+
+	interface = intf->cur_altsetting;
+
+	if (interface->desc.bNumEndpoints < 2)
+		goto bail_out_early;
+
+	/*
+	 * Allocate parport interface 
+	 */
+	ret = -ENOMEM;
+	priv = kzalloc_obj(struct parport_uss720_private);
+	if (!priv)
+		goto bail_out_early;
+
+	priv->pp = NULL;
+	priv->usbdev = usbdev;
+	kref_init(&priv->ref_count);
+	spin_lock_init(&priv->asynclock);
+	INIT_LIST_HEAD(&priv->asynclist);
+	pp = parport_register_port(0, PARPORT_IRQ_NONE, PARPORT_DMA_NONE, &parport_uss720_ops);
+	if (!pp) {
+		printk(KERN_WARNING "uss720: could not register parport\n");
+		goto probe_abort;
+	}
+
+	priv->pp = pp;
+	pp->private_data = priv;
+	pp->modes = PARPORT_MODE_PCSPP | PARPORT_MODE_TRISTATE | PARPORT_MODE_EPP | PARPORT_MODE_COMPAT;
+	if (interface->desc.bNumEndpoints >= 3)
+		pp->modes |= PARPORT_MODE_ECP;
+	pp->dev = &usbdev->dev;
+
+	/* set the USS720 control register to manual mode, no ECP compression, enable all ints */
+	set_1284_register(pp, 7, 0x00, GFP_KERNEL);
+	set_1284_register(pp, 6, 0x30, GFP_KERNEL);  /* PS/2 mode */
+	set_1284_register(pp, 2, 0x0c, GFP_KERNEL);
+
+	/* The Belkin F5U002 Rev 2 P80453-B USB parallel port adapter shares the
+	 * device ID 050d:0002 with some other device that works with this
+	 * driver, but it itself does not. Detect and handle the bad cable
+	 * here. */
+	ret = get_1284_register(pp, 0, &reg, GFP_KERNEL);
+	dev_dbg(&intf->dev, "reg: %7ph\n", priv->reg);
+	if (ret < 0) {
+		priv->pp = NULL;
+		parport_del_port(pp);
+		goto probe_abort;
+	}
+
+	ret = usb_find_last_int_in_endpoint(interface, &epd);
+	if (!ret) {
+		dev_dbg(&intf->dev, "epaddr %d interval %d\n",
+				epd->bEndpointAddress, epd->bInterval);
+	}
+	parport_announce_port(pp);
+
+	usb_set_intfdata(intf, pp);
+	return 0;
+
+probe_abort:
+	kill_all_async_requests_priv(priv);
+	kref_put(&priv->ref_count, destroy_priv);
+	return -ENODEV;
+
+bail_out_early:
+	usb_put_dev(usbdev);
+	return ret;
+}
+
+static void uss720_disconnect(struct usb_interface *intf)
+{
+	struct parport *pp = usb_get_intfdata(intf);
+	struct parport_uss720_private *priv;
+
+	dev_dbg(&intf->dev, "disconnect\n");
+	usb_set_intfdata(intf, NULL);
+	if (pp) {
+		priv = pp->private_data;
+		priv->pp = NULL;
+		dev_dbg(&intf->dev, "parport_remove_port\n");
+		parport_remove_port(pp);
+		parport_put_port(pp);
+		kill_all_async_requests_priv(priv);
+		kref_put(&priv->ref_count, destroy_priv);
+	}
+	dev_dbg(&intf->dev, "disconnect done\n");
+}
+
+/* table of cables that work through this driver */
+static const struct usb_device_id uss720_table[] = {
+	{ USB_DEVICE(0x047e, 0x1001) }, /* Infowave 901-0030 */
+	{ USB_DEVICE(0x04b8, 0x0002) }, /* Epson CAEUL0002 ISD-103 */
+	{ USB_DEVICE(0x04b8, 0x0003) }, /* Epson ISD-101 */
+	{ USB_DEVICE(0x050d, 0x0002) },
+	{ USB_DEVICE(0x050d, 0x1202) }, /* Belkin F5U120-PC */
+	{ USB_DEVICE(0x0557, 0x2001) },
+	{ USB_DEVICE(0x05ab, 0x0002) }, /* Belkin F5U002 ISD-101 */
+	{ USB_DEVICE(0x05ab, 0x1001) }, /* Belkin F5U002 P80453-A */
+	{ USB_DEVICE(0x06c6, 0x0100) }, /* Infowave ISD-103 */
+	{ USB_DEVICE(0x0729, 0x1284) },
+	{ USB_DEVICE(0x1293, 0x0002) },
+	{ }						/* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE (usb, uss720_table);
+
+
+static struct usb_driver uss720_driver = {
+	.name =		"uss720",
+	.probe =	uss720_probe,
+	.disconnect =	uss720_disconnect,
+	.id_table =	uss720_table,
+};
+
+/* --------------------------------------------------------------------- */
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+static int __init uss720_init(void)
+{
+	int retval;
+	retval = usb_register(&uss720_driver);
+	if (retval)
+		goto out;
+
+	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "\n");
+	printk(KERN_INFO KBUILD_MODNAME ": NOTE: this is a special purpose "
+	       "driver to allow nonstandard\n");
+	printk(KERN_INFO KBUILD_MODNAME ": protocols (eg. bitbang) over "
+	       "USS720 usb to parallel cables\n");
+	printk(KERN_INFO KBUILD_MODNAME ": If you just want to connect to a "
+	       "printer, use usblp instead\n");
+out:
+	return retval;
+}
+
+static void __exit uss720_cleanup(void)
+{
+	usb_deregister(&uss720_driver);
+}
+
+module_init(uss720_init);
+module_exit(uss720_cleanup);
+
+/* --------------------------------------------------------------------- */