From: Vitaliy Ivanov <vitalivanov@...>
Subject: [linux-usb-devel] [2.4 patch] Port of adutux driver from 2.6 kernel to 2.4.
Date: Oct 14, 1:37 pm 2007

Hello Willy, Greg and list,

I have ported adutux driver for ADU series device list from 2.6 to 2.4. 
More on devices:
http://www.ontrak.net/products.htm#Table%205

Once I needed to make ADU200 work under 2.4 enterprise kernel and wasn't able to do this.
My organization decided to use another device for our private purposes.

I was always interested in kernel hacking and thought it's a good point to start it from.
Just to add I'm not related to Ontrak in anyway. Also I'm not a Google person.
Did it just for fun.

A few technical notes:
- I was trying to leave as much as possible adutux driver code from 2.6 as it's in the 2.6 mainline for a long time and seems like it works OK there.
- Used one shot interrupt urbs that's why all intervals are 0.
- Reused 67 minor number from 2.6 kernel for this device.
- All 2.4 related changes are taken/reused from usb-skeleton.

Patch is based on the latest 2.4.35.3.

Performed a lot of tests but only under UHCI controller and ADU200 and all seems to be OK.

I would like someone to perform code review as it's my first attempt to the kernel programming. 
Any comments, propositions are welcome.

Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Tested-by: Vitaliy Ivanov <vitalivanov@gmail.com>

--

diff -uprN -X dontdiff KERNELS/linux-2.4.35.3/Documentation/Configure.help linux-2.4.35.3.build/Documentation/Configure.help
-- KERNELS/linux-2.4.35.3/Documentation/Configure.help	2007-09-24 01:02:58.000000000 +0300
+++ linux-2.4.35.3.build/Documentation/Configure.help	2007-10-14 19:19:06.000000000 +0300
@@ -16123,6 +16123,17 @@ CONFIG_USB_RIO500
   The module will be called rio500.o. If you want to compile it as
   a module, say M here and read <file:Documenatation/modules.txt>.
 
+Ontrak Control Systems ADU devices support
+CONFIG_USB_ADUTUX
+  Say Y here if you want to connect ADU 100/200 series devices to your
+  computer's USB port. 
+  Details at: <http://www.ontrak.net/products.htm#Table%205>
+
+  This code is also available as a module ( = code which can be
+  inserted in and removed from the running kernel whenever you want).
+  The module will be called adutux.o. If you want to compile it as
+  a module, say M here and read <file:Documenatation/modules.txt>.
+
 Auerswald device support
 CONFIG_USB_AUERSWALD
   Say Y here if you want to connect an Auerswald USB ISDN Device
diff -uprN -X dontdiff KERNELS/linux-2.4.35.3/drivers/usb/adutux.c linux-2.4.35.3.build/drivers/usb/adutux.c
-- KERNELS/linux-2.4.35.3/drivers/usb/adutux.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.4.35.3.build/drivers/usb/adutux.c	2007-10-14 19:08:59.000000000 +0300
@@ -0,0 +1,1035 @@
+/*
+ * This is a 2.4.* kernel version of adutux driver that
+ * was originaly created by John Homppi for 2.6.* kernels.
+ * 
+ * Copyright (c) 2007 Vitaliy Ivanov (vitalivanov@gmail.com)
+ *
+ * Original note:
+ *
+ * adutux - driver for ADU devices from Ontrak Control Systems
+ * This is an experimental driver. Use at your own risk.
+ * This driver is not supported by Ontrak Control Systems.
+ *
+ * Copyright (c) 2003 John Homppi (SCO, leave this notice here)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * derived from the Lego USB Tower driver 0.56:
+ * Copyright (c) 2003 David Glance <davidgsf@sourceforge.net>
+ *               2001 Juergen Stuber <stuber@loria.fr>
+ * that was derived from USB Skeleton driver - 0.5
+ * Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/usb.h>
+#include <asm/uaccess.h>
+
+#ifdef CONFIG_USB_DEBUG
+static int debug = 5;
+#else
+static int debug = 1;
+#endif
+
+/* Use our own dbg macro */
+#undef dbg
+#define dbg(lvl, format, arg...) 					\
+do { 									\
+	if (debug >= lvl)						\
+		printk(KERN_DEBUG __FILE__ " : " format " \n", ## arg);	\
+} while (0)
+
+
+/* Version Information */
+#define DRIVER_VERSION "v0.0.1"
+#define DRIVER_AUTHOR "Vitaliy Ivanov"
+#define DRIVER_DESC "adutux (see www.ontrak.net)"
+
+/* Module parameters */
+module_param(debug, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Debug enabled or not");
+
+/* Define these values to match your device */
+#define ADU_VENDOR_ID 0x0a07
+#define ADU_PRODUCT_ID 0x0064
+
+/* table of devices that work with this driver */
+static struct usb_device_id device_table [] = {
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },		/* ADU100 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) },	/* ADU120 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) },	/* ADU130 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },	/* ADU200 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },	/* ADU208 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },	/* ADU218 */
+	{ }/* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, device_table);
+
+#define ADU_MINOR_BASE	67
+
+/* we can have up to this number of device plugged in at once */
+#define MAX_DEVICES	16
+
+#define COMMAND_TIMEOUT	(2*HZ)	/* 60 second timeout for a command */
+
+/* Structure to hold all of our device specific stuff */
+struct adu_device {
+	struct semaphore	sem;	/* locks this structure */
+	struct usb_device*	udev;	/* save off the usb device pointer */
+	//struct usb_interface*	interface;
+	devfs_handle_t		devfs;	/* devfs device node */
+	unsigned char		minor;	/* the starting minor number for this device */
+
+	int			open_count;	/* number of times this port has been opened */
+
+	char*			read_buffer_primary;
+	int			read_buffer_length;
+	char*			read_buffer_secondary;
+	int			secondary_head;
+	int			secondary_tail;
+	spinlock_t		buflock;
+
+	wait_queue_head_t	read_wait;
+	wait_queue_head_t	write_wait;
+
+	char*			interrupt_in_buffer;
+	struct usb_endpoint_descriptor*	interrupt_in_endpoint;
+	struct urb*		interrupt_in_urb;
+	int			read_urb_finished;
+
+	char*			interrupt_out_buffer;
+	struct usb_endpoint_descriptor*	interrupt_out_endpoint;
+	struct urb*		interrupt_out_urb;
+};
+
+/* the global usb devfs handle */
+extern devfs_handle_t	usb_devfs_handle;
+
+/* local function prototypes */
+static ssize_t adu_read(struct file *file, char *buffer, size_t count, loff_t *ppos);
+static ssize_t adu_write(struct file *file, const char *buffer, size_t count, loff_t *ppos);
+static void adu_delete(struct adu_device *dev);
+static int adu_open(struct inode *inode, struct file *file);
+static int adu_release(struct inode *inode, struct file *file);
+static int adu_release_internal(struct adu_device *dev);
+static void adu_interrupt_in_callback(struct urb *urb);
+static void adu_interrupt_out_callback(struct urb *urb);
+static void *adu_probe(struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *id);
+static void adu_disconnect(struct usb_device *dev, void *ptr);
+
+/* array of pointers to our devices that are currently connected */
+static struct adu_device	*minor_table[MAX_DEVICES];
+
+/* lock to protect the minor_table structure */
+static DECLARE_MUTEX(minor_table_mutex);
+
+/* file operations needed when we register this driver */
+static struct file_operations adu_fops = {
+	owner:		THIS_MODULE,
+	read:		adu_read,
+	write:		adu_write,
+	open:		adu_open,
+	release:	adu_release,
+};
+
+/* usb specific object needed to register this driver with the usb subsystem */
+static struct usb_driver adu_driver = {
+	name:		"adutux",
+	probe:		adu_probe,
+	disconnect:	adu_disconnect,
+	fops:		&adu_fops,
+	minor:		ADU_MINOR_BASE,
+	id_table:	device_table,
+};
+
+/**
+ *  adu_debug_data
+ */
+static void adu_debug_data(int level, const char *function, int size,
+			   const unsigned char *data)
+{
+	int i;
+
+	if (debug < level)
+		return;
+
+	printk(KERN_DEBUG __FILE__": %s - length = %d, data = ",
+	       function, size);
+	for (i = 0; i < size; ++i)
+		printk("%.2x ", data[i]);
+	printk("\n");
+}
+
+/**
+ * adu_abort_transfers
+ *      aborts transfers and frees associated data structures
+ */
+static void adu_abort_transfers(struct adu_device *dev)
+{
+	dbg(2," %s : enter", __FUNCTION__);
+
+	if (dev == NULL) {
+		dbg(1," %s : dev is null", __FUNCTION__);
+		goto exit;
+	}
+
+	if (dev->udev == NULL) {
+		dbg(1," %s : udev is null", __FUNCTION__);
+		goto exit;
+	}
+
+	/* shutdown transfer */
+	usb_unlink_urb(dev->interrupt_in_urb);
+	usb_unlink_urb(dev->interrupt_out_urb);
+
+exit:
+	dbg(2," %s : leave", __FUNCTION__);
+}
+
+/**
+ *  adu_delete
+ */
+static void adu_delete(struct adu_device *dev)
+{
+	dbg(2, "%s enter", __FUNCTION__);
+
+	minor_table[dev->minor] = NULL;
+	adu_abort_transfers(dev);
+
+	/* free data structures */
+	if (dev->interrupt_in_urb != NULL) {
+		usb_free_urb(dev->interrupt_in_urb);
+	}
+	if (dev->interrupt_out_urb != NULL) {
+		usb_free_urb(dev->interrupt_out_urb);
+	}
+	if (dev->read_buffer_primary != NULL) {
+		kfree(dev->read_buffer_primary);
+	}
+	if (dev->read_buffer_secondary != NULL) {
+		kfree(dev->read_buffer_secondary);
+	}
+	if (dev->interrupt_in_buffer != NULL) {
+		kfree(dev->interrupt_in_buffer);
+	}
+	if (dev->interrupt_out_buffer != NULL) {
+		kfree(dev->interrupt_out_buffer);
+	}
+	kfree(dev);
+
+	dbg(2, "%s : leave", __FUNCTION__);
+}
+
+/**
+ *  adu_interrupt_in_callback
+ */
+static void adu_interrupt_in_callback(struct urb *urb)
+{
+	struct adu_device *dev = urb->context;
+
+	dbg(4," %s : enter, status %d", __FUNCTION__, urb->status);
+	adu_debug_data(5, __FUNCTION__, urb->actual_length,
+		       urb->transfer_buffer);
+
+	spin_lock(&dev->buflock);
+
+	if (urb->status != 0) {
+		if ((urb->status != -ENOENT) && (urb->status != -ECONNRESET) &&
+			(urb->status != -ESHUTDOWN)) {
+			dbg(1," %s : nonzero status received: %d",
+			    __FUNCTION__, urb->status);
+		}
+		goto exit;
+	}
+
+	if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
+		if (dev->read_buffer_length <
+		    (4 * le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize)) -
+		     (urb->actual_length)) {
+			memcpy (dev->read_buffer_primary +
+				dev->read_buffer_length,
+				dev->interrupt_in_buffer, urb->actual_length);
+
+			dev->read_buffer_length += urb->actual_length;
+			dbg(2," %s reading  %d ", __FUNCTION__,
+			    urb->actual_length);
+		} else {
+			dbg(1," %s : read_buffer overflow", __FUNCTION__);
+		}
+	}
+
+exit:
+	dev->read_urb_finished = 1;
+	spin_unlock(&dev->buflock);
+	/* always wake up so we recover from errors */
+	wake_up_interruptible(&dev->read_wait);
+	adu_debug_data(5, __FUNCTION__, urb->actual_length,
+		       urb->transfer_buffer);
+	dbg(4," %s : leave, status %d", __FUNCTION__, urb->status);
+}
+
+/**
+ *  adu_interrupt_out_callback
+ */
+static void adu_interrupt_out_callback(struct urb *urb)
+{
+	struct adu_device *dev = urb->context;
+
+	dbg(4," %s : enter, status %d", __FUNCTION__, urb->status);
+	adu_debug_data(5,__FUNCTION__, urb->actual_length, urb->transfer_buffer);
+
+	if (urb->status != 0) {
+		if ((urb->status != -ENOENT) &&
+		    (urb->status != -ECONNRESET)) {
+			dbg(1, " %s :nonzero status received: %d",
+			    __FUNCTION__, urb->status);
+		}
+		goto exit;
+	}
+
+	wake_up_interruptible(&dev->write_wait);
+exit:
+
+	adu_debug_data(5, __FUNCTION__, urb->actual_length,
+		       urb->transfer_buffer);
+	dbg(4," %s : leave, status %d", __FUNCTION__, urb->status);
+}
+
+/**
+ *  adu_open
+ */
+static int adu_open(struct inode *inode, struct file *file)
+{
+	struct adu_device *dev = NULL;
+	int subminor;
+	int retval = 0;
+
+	dbg(2,"%s : enter", __FUNCTION__);
+
+	subminor = MINOR (inode->i_rdev) - ADU_MINOR_BASE;
+	if ((subminor < 0) ||
+	    (subminor >= MAX_DEVICES)) {
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	/* lock our minor table and get our local data for this minor */
+	down (&minor_table_mutex);
+	dev = minor_table[subminor];
+	if (dev == NULL) {
+		retval = -ENODEV;
+		goto unlock_minor_table_exit;
+	}
+
+	/* lock this device */
+	down (&dev->sem);
+
+	/* increment our usage count for the device */
+	++dev->open_count;
+	dbg(2,"%s : open count %d", __FUNCTION__, dev->open_count);
+
+	/* check that nobody else is using the device */
+	/* NOTE: the cleanup code will decrement the count to 1 */
+	if (dev->open_count > 1) {
+		retval = -EBUSY;
+		goto error;
+	}
+
+	/* save device in the file's private structure */
+	file->private_data = dev;
+
+	/* initialize in direction */
+	dev->read_buffer_length = 0;
+
+	/* fixup first read by having urb waiting for it */
+	FILL_INT_URB(dev->interrupt_in_urb,
+		     dev->udev,
+		     usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
+		     dev->interrupt_in_buffer,
+		     le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
+		     adu_interrupt_in_callback,
+		     dev,
+		     0);
+
+	/* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
+	dev->read_urb_finished = 0;
+	retval = usb_submit_urb(dev->interrupt_in_urb);
+	if (retval != 0) {
+		err("Couldn't submit interrupt_in_urb");
+		goto error;
+	}
+	/* end of fixup for first read */
+
+	goto unlock_exit;
+
+error:
+	adu_release_internal(dev);
+
+unlock_exit:
+	/* unlock this device */
+	up(&dev->sem);
+
+unlock_minor_table_exit:
+	/* unlock the minor table */
+	up(&minor_table_mutex);
+
+exit:
+	dbg(2, " %s : leave, return value %d", __FUNCTION__, retval);
+
+	return retval;
+}
+
+/**
+ *	adu_release_internal
+ */
+static int adu_release_internal(struct adu_device *dev)
+{
+	int retval = 0;
+
+	dbg(2," %s : enter", __FUNCTION__);
+
+	if (dev->udev == NULL) {
+		/* the device was unplugged before the file was released */
+		adu_delete(dev);
+		goto exit;
+	}
+
+	/* decrement our usage count for the device */
+	--dev->open_count;
+	dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
+	if (dev->open_count <= 0) {
+		adu_abort_transfers(dev);
+		dev->open_count = 0;
+	}
+
+exit:
+	dbg(2," %s : leave", __FUNCTION__);
+	return retval;
+}
+
+/**
+ *	adu_release
+ */
+static int adu_release(struct inode *inode, struct file *file)
+{
+	struct adu_device *dev = NULL;
+	int retval = 0;
+
+	dbg(2," %s : enter", __FUNCTION__);
+
+	if (file == NULL) {
+		dbg(1," %s : file is NULL", __FUNCTION__);
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	dev = file->private_data;
+
+	if (dev == NULL) {
+		dbg(1," %s : object is NULL", __FUNCTION__);
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	/* lock our minor table */
+	down(&minor_table_mutex);
+
+	/* lock our device */
+	down(&dev->sem);
+
+	if (dev->open_count <= 0) {
+		dbg(1," %s : device not opened", __FUNCTION__);
+		up(&dev->sem);
+		up(&minor_table_mutex);
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	/* do the work */
+	retval = adu_release_internal(dev);
+
+	/* unlocking device */
+	up(&dev->sem);
+	up(&minor_table_mutex);
+
+exit:
+	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
+	return retval;
+}
+
+/**
+ *	adu_read
+ */
+static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
+			loff_t *ppos)
+{
+	struct adu_device *dev;
+	size_t bytes_read = 0;
+	size_t bytes_to_read = count;
+	int i;
+	int retval = 0;
+	int timeout = 0;
+	int should_submit = 0;
+	unsigned long flags;
+	DECLARE_WAITQUEUE(wait, current);
+
+	dbg(2," %s : enter, count = %Zd, file=%p", __FUNCTION__, count, file);
+
+	dev = file->private_data;
+	dbg(2," %s : dev=%p", __FUNCTION__, dev);
+	/* lock this object */
+	if (down_interruptible(&dev->sem))
+		return -ERESTARTSYS;
+
+	/* verify that the device wasn't unplugged */
+	if (dev->udev == NULL) {
+		retval = -ENODEV;
+		err("No device or device unplugged %d", retval);
+		goto exit;
+	}
+
+	/* verify that some data was requested */
+	if (count == 0) {
+		dbg(1," %s : read request of 0 bytes", __FUNCTION__);
+		goto exit;
+	}
+
+	timeout = COMMAND_TIMEOUT;
+	dbg(2," %s : about to start looping", __FUNCTION__);
+	while (bytes_to_read) {
+		int data_in_secondary = dev->secondary_tail - dev->secondary_head;
+		dbg(2," %s : while, data_in_secondary=%d, status=%d",
+		    __FUNCTION__, data_in_secondary,
+		    dev->interrupt_in_urb->status);
+
+		if (data_in_secondary) {
+			/* drain secondary buffer */
+			int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
+			i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
+			if (i < 0) {
+				retval = -EFAULT;
+				goto exit;
+			}
+			dev->secondary_head += (amount - i);
+			bytes_read += (amount - i);
+			bytes_to_read -= (amount - i);
+			if (i) {
+				retval = bytes_read ? bytes_read : -EFAULT;
+				goto exit;
+			}
+		} else {
+			/* we check the primary buffer */
+			spin_lock_irqsave (&dev->buflock, flags);
+			if (dev->read_buffer_length) {
+				/* we secure access to the primary */
+				char *tmp;
+				dbg(2," %s : swap, read_buffer_length = %d",
+				    __FUNCTION__, dev->read_buffer_length);
+				tmp = dev->read_buffer_secondary;
+				dev->read_buffer_secondary = dev->read_buffer_primary;
+				dev->read_buffer_primary = tmp;
+				dev->secondary_head = 0;
+				dev->secondary_tail = dev->read_buffer_length;
+				dev->read_buffer_length = 0;
+				spin_unlock_irqrestore(&dev->buflock, flags);
+				/* we have a free buffer so use it */
+				should_submit = 1;
+			} else {
+				/* even the primary was empty - we may need to do IO */
+				if (dev->interrupt_in_urb->status == -EINPROGRESS) {
+					/* somebody is doing IO */
+					spin_unlock_irqrestore(&dev->buflock, flags);
+					dbg(2," %s : submitted already", __FUNCTION__);
+				} else {
+					/* we must initiate input */
+					dbg(2," %s : initiate input", __FUNCTION__);
+					dev->read_urb_finished = 0;
+
+					FILL_INT_URB(dev->interrupt_in_urb,
+						     dev->udev,
+						     usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
+						     dev->interrupt_in_buffer,
+						     le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
+						     adu_interrupt_in_callback,
+						     dev,
+						     0);
+
+					retval = usb_submit_urb(dev->interrupt_in_urb);
+					if (!retval) {
+						spin_unlock_irqrestore(&dev->buflock, flags);
+						dbg(2," %s : submitted OK", __FUNCTION__);
+					} else {
+						if (retval == -ENOMEM) {
+							retval = bytes_read ? bytes_read : -ENOMEM;
+						}
+						spin_unlock_irqrestore(&dev->buflock, flags);
+						dbg(2," %s : submit failed", __FUNCTION__);
+						goto exit;
+					}
+				}
+
+				/* we wait for I/O to complete */
+				set_current_state(TASK_INTERRUPTIBLE);
+				add_wait_queue(&dev->read_wait, &wait);
+				if (!dev->read_urb_finished)
+					timeout = schedule_timeout(COMMAND_TIMEOUT);
+				else
+					set_current_state(TASK_RUNNING);
+				remove_wait_queue(&dev->read_wait, &wait);
+
+				if (timeout <= 0) {
+					dbg(2," %s : timeout", __FUNCTION__);
+					retval = bytes_read ? bytes_read : -ETIMEDOUT;
+					goto exit;
+				}
+
+				if (signal_pending(current)) {
+					dbg(2," %s : signal pending", __FUNCTION__);
+					retval = bytes_read ? bytes_read : -EINTR;
+					goto exit;
+				}
+			}
+		}
+	}
+
+	retval = bytes_read;
+	/* if the primary buffer is empty then use it */
+	if (should_submit && !dev->interrupt_in_urb->status==-EINPROGRESS) {
+		FILL_INT_URB(dev->interrupt_in_urb,
+			     dev->udev,
+			     usb_rcvintpipe(dev->udev,dev->interrupt_in_endpoint->bEndpointAddress),
+			     dev->interrupt_in_buffer,
+			     le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
+			     adu_interrupt_in_callback,
+			     dev,
+			     0);
+
+		/* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
+		dev->read_urb_finished = 0;
+		usb_submit_urb(dev->interrupt_in_urb);
+		/* we ignore failure */
+	}
+
+exit:
+	/* unlock the device */
+	up(&dev->sem);
+
+	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
+	return retval;
+}
+
+/**
+ *	adu_write
+ */
+static ssize_t adu_write(struct file *file, const __user char *buffer,
+			 size_t count, loff_t *ppos)
+{
+	struct adu_device *dev;
+	size_t bytes_written = 0;
+	size_t bytes_to_write;
+	size_t buffer_size;
+	int retval = 0;
+	int timeout = 0;
+
+	dbg(2," %s : enter, count = %Zd", __FUNCTION__, count);
+
+	dev = file->private_data;
+
+	/* lock this object */
+	down_interruptible(&dev->sem);
+
+	/* verify that the device wasn't unplugged */
+	if (dev->udev == NULL) {
+		retval = -ENODEV;
+		err("No device or device unplugged %d", retval);
+		goto exit;
+	}
+
+	/* verify that we actually have some data to write */
+	if (count == 0) {
+		dbg(1," %s : write request of 0 bytes", __FUNCTION__);
+		goto exit;
+	}
+
+
+	while (count > 0) {
+		if (dev->interrupt_out_urb->status == -EINPROGRESS) {
+			timeout = COMMAND_TIMEOUT;
+
+			while (timeout > 0) {
+				if (signal_pending(current)) {
+				dbg(1," %s : interrupted", __FUNCTION__);
+				retval = -EINTR;
+				goto exit;
+			}
+			up(&dev->sem);
+			timeout = interruptible_sleep_on_timeout(&dev->write_wait, timeout);
+			down_interruptible(&dev->sem);
+			if (timeout > 0) {
+				break;
+			}
+			dbg(1," %s : interrupted timeout: %d", __FUNCTION__, timeout);
+		}
+
+
+		dbg(1," %s : final timeout: %d", __FUNCTION__, timeout);
+
+		if (timeout == 0) {
+			dbg(1, "%s - command timed out.", __FUNCTION__);
+			retval = -ETIMEDOUT;
+			goto exit;
+		}
+
+		dbg(4," %s : in progress, count = %Zd", __FUNCTION__, count);
+
+		} else {
+			dbg(4," %s : sending, count = %Zd", __FUNCTION__, count);
+
+			/* write the data into interrupt_out_buffer from userspace */
+			buffer_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);
+			bytes_to_write = count > buffer_size ? buffer_size : count;
+			dbg(4," %s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd",
+			    __FUNCTION__, buffer_size, count, bytes_to_write);
+
+			if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
+				retval = -EFAULT;
+				goto exit;
+			}
+
+			/* send off the urb */
+			FILL_INT_URB(
+				     dev->interrupt_out_urb,
+				     dev->udev,
+				     usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
+				     dev->interrupt_out_buffer,
+				     bytes_to_write,
+				     adu_interrupt_out_callback,
+				     dev,
+				     0);
+
+			/* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
+			dev->interrupt_out_urb->actual_length = bytes_to_write;
+			retval = usb_submit_urb(dev->interrupt_out_urb);
+			if (retval < 0) {
+				err("Couldn't submit interrupt_out_urb %d", retval);
+				goto exit;
+			}
+
+			buffer += bytes_to_write;
+			count -= bytes_to_write;
+
+			bytes_written += bytes_to_write;
+		}
+	}
+
+	retval = bytes_written;
+
+exit:
+	/* unlock the device */
+	up(&dev->sem);
+
+	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
+
+	return retval;
+}
+
+/**
+ * adu_probe
+ *
+ * Called by the usb core when a new device is connected that it thinks
+ * this driver might be interested in.
+ */
+static void *adu_probe(struct usb_device *udev, 
+		       unsigned int ifnum, const struct usb_device_id *id)
+{
+	struct adu_device *dev = NULL;
+	struct usb_interface *interface;
+	struct usb_interface_descriptor *iface_desc;
+	struct usb_endpoint_descriptor *endpoint;
+	int minor;
+	int in_end_size;
+	int out_end_size;
+	int i;
+	char name[10];
+	void *retval = NULL;
+
+	dbg(2, " %s : enter", __FUNCTION__);
+
+	if (udev == NULL) {
+		info ("udev is NULL.");
+		goto exit;
+	}
+
+	if (ifnum != 0) {
+		info ("Strange interface number %d.", ifnum);
+		goto exit;
+	}
+
+	/* select a "subminor" number (part of a minor number) */
+	down (&minor_table_mutex);
+	for (minor = 0; minor < MAX_DEVICES; ++minor) {
+		if (minor_table[minor] == NULL)
+			break;
+	}
+	if (minor >= MAX_DEVICES) {
+		info ("Too many devices plugged in, can not handle this device.");
+		goto unlock_minor_exit;
+	}
+
+	/* allocate memory for our device state and intialize it */
+	dev = kmalloc(sizeof(struct adu_device), GFP_KERNEL);
+	if (dev == NULL) {
+		err ("Out of memory");
+		goto unlock_minor_exit;
+	}
+	memset (dev, 0x00, sizeof (*dev));
+
+	init_MUTEX(&dev->sem);
+	spin_lock_init(&dev->buflock);
+	down(&dev->sem);
+	dev->udev = udev;
+
+	interface = &dev->udev->actconfig->interface[0];
+	iface_desc = &interface->altsetting[0];
+
+	//dev->interface = interface;
+	dev->minor = minor;
+	dev->open_count = 0;
+
+	dev->read_buffer_primary = NULL;
+	dev->read_buffer_secondary = NULL;
+	dev->read_buffer_length = 0;
+
+	dev->secondary_head = 0;
+	dev->secondary_tail = 0;
+
+	init_waitqueue_head(&dev->read_wait);
+	init_waitqueue_head(&dev->write_wait);
+
+	dev->interrupt_in_buffer = NULL;
+	dev->interrupt_in_endpoint = NULL;
+	dev->interrupt_in_urb = NULL;
+
+	dev->interrupt_out_buffer = NULL;
+	dev->interrupt_out_endpoint = NULL;
+	dev->interrupt_out_urb = NULL;
+
+	dev->read_urb_finished = 0;
+
+	/* set up the endpoint information */
+	for (i = 0; i < iface_desc->bNumEndpoints; ++i) {
+		endpoint = &iface_desc->endpoint[i];
+
+		/** 
+		 * Check if the endpoint has IN direction
+		 * and check if the endpoint has interrupt transfer type
+		 */
+		if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN) &&
+		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
+			/* we found an interrupt in endpoint */
+			dev->interrupt_in_endpoint = endpoint;
+		}
+
+		/** 
+		 * Check if the endpoint has OUT direction
+		 * and check if the endpoint has interrupt transfer type
+		 */
+		if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT) &&
+		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
+			/* we found an interrupt out endpoint */
+			dev->interrupt_out_endpoint = endpoint;
+		}
+	}
+
+	if(dev->interrupt_in_endpoint == NULL) {
+		err("interrupt in endpoint not found");
+		goto error;
+	}
+	if (dev->interrupt_out_endpoint == NULL) {
+		err("interrupt out endpoint not found");
+		goto error;
+	}
+
+	in_end_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
+	out_end_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);
+
+	dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
+	if (!dev->read_buffer_primary) {
+		err("Couldn't allocate read_buffer_primary");
+		goto error;
+	}
+
+	/* debug code prime the buffer */
+	memset(dev->read_buffer_primary, 'a', in_end_size);
+	memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
+	memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
+	memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
+
+	dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
+	if (!dev->read_buffer_secondary) {
+		err("Couldn't allocate read_buffer_secondary");
+		goto error;
+	}
+
+	/* debug code prime the buffer */
+	memset(dev->read_buffer_secondary, 'e', in_end_size);
+	memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
+	memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
+	memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
+
+	dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
+	if (!dev->interrupt_in_buffer) {
+		err("Couldn't allocate interrupt_in_buffer");
+		goto error;
+	}
+
+	/* debug code prime the buffer */
+	memset(dev->interrupt_in_buffer, 'i', in_end_size);
+
+	dev->interrupt_in_urb = usb_alloc_urb(0);
+	if (!dev->interrupt_in_urb) {
+		err("Couldn't allocate interrupt_in_urb");
+		goto error;
+	}
+	dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
+	if (!dev->interrupt_out_buffer) {
+		err("Couldn't allocate interrupt_out_buffer");
+		goto error;
+	}
+	dev->interrupt_out_urb = usb_alloc_urb(0);
+	if (!dev->interrupt_out_urb) {
+		err("Couldn't allocate interrupt_out_urb");
+		goto error;
+	}
+
+	/* put dev in interface->private_data for disconnect */
+	udev->actconfig->interface[0].private_data = dev;
+
+	/* publish it */
+	minor_table[minor] = dev;
+
+	/* initialize the devfs node for this device and register it */
+	sprintf(name, "adutux%d", dev->minor);
+
+	dev->devfs = devfs_register(usb_devfs_handle, name,
+				    DEVFS_FL_DEFAULT, USB_MAJOR,
+				    ADU_MINOR_BASE + dev->minor,
+				    S_IFCHR | S_IRUSR | S_IWUSR | 
+				    S_IRGRP | S_IWGRP | S_IROTH, 
+				    &adu_fops, NULL);
+
+	/* let the user know what node this device is now attached to */
+	info ("ADU%d now attached to /dev/usb/adutux%d", udev->descriptor.idProduct, dev->minor);
+
+	retval = dev;
+	/* unlock device */
+	up(&dev->sem);
+	goto unlock_minor_exit;
+
+error:
+	/* unlock device */
+	up(&dev->sem);
+	adu_delete(dev);
+	dev = NULL;
+
+unlock_minor_exit:
+	up(&minor_table_mutex);
+
+exit:
+	dbg(2," %s : leave, return value 0x%.8lx (dev)", __FUNCTION__, (dev)?(long)dev:0);
+
+	return retval;
+}
+
+/**
+ * adu_disconnect
+ *
+ * Called by the usb core when the device is removed from the system.
+ */
+static void adu_disconnect(struct usb_device *udev, void *ptr)
+{
+	struct adu_device *dev;
+	int minor;
+
+	dbg(2," %s : enter", __FUNCTION__);
+
+	dev = (struct adu_device *)ptr;
+
+	down (&minor_table_mutex);
+	down (&dev->sem);
+
+	minor = dev->minor;
+
+	/* remove our devfs node */
+	devfs_unregister(dev->devfs);
+
+	/* if the device is not opened, then we clean up right now */
+	dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
+	if (!dev->open_count) {
+		up (&dev->sem);
+		adu_delete(dev);
+	} else {
+		dev->udev = NULL;
+		up (&dev->sem);
+	}
+
+	up (&minor_table_mutex);    
+	info("ADU device adutux%d now disconnected", minor);
+
+	dbg(2," %s : leave", __FUNCTION__);
+}
+
+/**
+ *	adu_init
+ */
+static int __init adu_init(void)
+{
+	int result;
+
+	dbg(2," %s : enter", __FUNCTION__);
+
+	/* register this driver with the USB subsystem */
+	result = usb_register(&adu_driver);
+	if (result < 0) {
+		err("usb_register failed for the "__FILE__" driver. "
+		    "Error number %d", result);
+		goto exit;
+	}
+
+	info("adutux " DRIVER_DESC " " DRIVER_VERSION);
+	info("adutux is an experimental driver. Use at your own risk");
+
+exit:
+	dbg(2," %s : leave, return value %d", __FUNCTION__, result);
+
+	return result;
+}
+
+/**
+ *	adu_exit
+ */
+static void __exit adu_exit(void)
+{
+	dbg(2," %s : enter", __FUNCTION__);
+	/* deregister this driver with the USB subsystem */
+	usb_deregister(&adu_driver);
+	dbg(2," %s : leave", __FUNCTION__);
+}
+
+module_init(adu_init);
+module_exit(adu_exit);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
diff -uprN -X dontdiff KERNELS/linux-2.4.35.3/drivers/usb/Config.in linux-2.4.35.3.build/drivers/usb/Config.in
-- KERNELS/linux-2.4.35.3/drivers/usb/Config.in	2007-09-24 01:02:58.000000000 +0300
+++ linux-2.4.35.3.build/drivers/usb/Config.in	2007-10-10 19:49:19.000000000 +0300
@@ -102,6 +102,7 @@ if [ "$CONFIG_USB" = "y" -o  "$CONFIG_US
 
    comment 'USB Miscellaneous drivers'
    dep_tristate '  USB Diamond Rio500 support (EXPERIMENTAL)' CONFIG_USB_RIO500 $CONFIG_USB $CONFIG_EXPERIMENTAL
+   dep_tristate '  ADU devices from Ontrak Control Systems (EXPERIMENTAL)' CONFIG_USB_ADUTUX $CONFIG_USB $CONFIG_EXPERIMENTAL
    dep_tristate '  Auerswald device support' CONFIG_USB_AUERSWALD $CONFIG_USB
    dep_tristate '  Texas Instruments Graph Link USB (aka SilverLink) cable support' CONFIG_USB_TIGL $CONFIG_USB
    dep_tristate '  Tieman Voyager USB Braille display support (EXPERIMENTAL)' CONFIG_USB_BRLVGER $CONFIG_USB $CONFIG_EXPERIMENTAL
diff -uprN -X dontdiff KERNELS/linux-2.4.35.3/drivers/usb/Makefile linux-2.4.35.3.build/drivers/usb/Makefile
-- KERNELS/linux-2.4.35.3/drivers/usb/Makefile	2007-09-24 01:02:58.000000000 +0300
+++ linux-2.4.35.3.build/drivers/usb/Makefile	2007-10-10 19:49:19.000000000 +0300
@@ -112,6 +112,7 @@ obj-$(CONFIG_USB_CATC)		+= catc.o
 obj-$(CONFIG_USB_KAWETH)        += kaweth.o
 obj-$(CONFIG_USB_CDCETHER)	+= CDCEther.o
 obj-$(CONFIG_USB_RIO500)	+= rio500.o
+obj-$(CONFIG_USB_ADUTUX)	+= adutux.o
 obj-$(CONFIG_USB_TIGL)          += tiglusb.o
 obj-$(CONFIG_USB_DSBR)		+= dsbr100.o
 obj-$(CONFIG_USB_MICROTEK)	+= microtek.o


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From: Willy Tarreau <w@...>
Subject: Re: [linux-usb-devel] [2.4 patch] Port of adutux driver from 2.6 kernel to 2.4.
Date: Oct 14, 2:25 pm 2007

Hello Vitaliy,

On Sun, Oct 14, 2007 at 08:37:25PM +0300, Vitaliy Ivanov wrote:
> Hello Willy, Greg and list,
> 
> I have ported adutux driver for ADU series device list from 2.6 to 2.4. 
> More on devices:
> http://www.ontrak.net/products.htm#Table%205
> 
> Once I needed to make ADU200 work under 2.4 enterprise kernel and wasn't able to do this.
> My organization decided to use another device for our private purposes.
> 
> I was always interested in kernel hacking and thought it's a good point to start it from.
> Just to add I'm not related to Ontrak in anyway. Also I'm not a Google person.
> Did it just for fun.
> 
> A few technical notes:
> - I was trying to leave as much as possible adutux driver code from 2.6 as it's in the 2.6 mainline for a long time and seems like it works OK there.
> - Used one shot interrupt urbs that's why all intervals are 0.
> - Reused 67 minor number from 2.6 kernel for this device.
> - All 2.4 related changes are taken/reused from usb-skeleton.
> 
> Patch is based on the latest 2.4.35.3.
> 
> Performed a lot of tests but only under UHCI controller and ADU200 and all seems to be OK.
> 
> I would like someone to perform code review as it's my first attempt to the kernel programming. 
> Any comments, propositions are welcome.

At first glance, your backport looks clean. I have one comment however,
about the author and version. Since it's a backport from an existing
driver and not one you wrote yourself (eventhough you did the backporting
work), the MODULE_AUTHOR should not be changed (but I think you can add
yourself to it after a comma). The version should reflect the version you
derived it from, at least for bug tracking purposes.

Also, while I understand you would be very glad to get your work merged
(we all once had our first piece of code), I'd like to mention that you
seem to be the only user of this hardware under 2.4 (since it is currently
not supported). I'm not sure it's very reasonable to merge a driver in 2.4
right now for just one user. Even more, I understand that you finally moved
to other hardware, so my feeling is that you did this work as an exercice
(which was cleanly performed, BTW), but that it will not get any real use
in 2.4.

Since 2.4 is moving very slowly, there should be no problem applying
this patch to any version if you really need to use it. Maybe it would
even work with your 2.4 enterprise kernel.

Note that I'm not radically opposed to merge support for new drivers.
If you provide us with really good arguments for a merge, maybe I'll
change my opinion, but I doubt about it, since the only users of this
device must currently be running 2.6.

Thanks,
Willy


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From: Vitaliy Ivanov <vitalivanov@...>
Subject: Re: [linux-usb-devel] [2.4 patch] Port of adutux driver from 2.6 kernel to 2.4.
Date: Oct 14, 4:45 pm 2007

Willy,

On 10/14/07, Willy Tarreau <w@1wt.eu> wrote:
> Hello Vitaliy,
>
> On Sun, Oct 14, 2007 at 08:37:25PM +0300, Vitaliy Ivanov wrote:
> > Hello Willy, Greg and list,
> >
> > I have ported adutux driver for ADU series device list from 2.6 to 2.4.
> > More on devices:
> > http://www.ontrak.net/products.htm#Table%205
> >
> > Once I needed to make ADU200 work under 2.4 enterprise kernel and wasn't able to do this.
> > My organization decided to use another device for our private purposes.
> >
> > I was always interested in kernel hacking and thought it's a good point to start it from.
> > Just to add I'm not related to Ontrak in anyway. Also I'm not a Google person.
> > Did it just for fun.
> >
> > A few technical notes:
> > - I was trying to leave as much as possible adutux driver code from 2.6 as it's in the 2.6 mainline for a long time and seems like it works OK there.
> > - Used one shot interrupt urbs that's why all intervals are 0.
> > - Reused 67 minor number from 2.6 kernel for this device.
> > - All 2.4 related changes are taken/reused from usb-skeleton.
> >
> > Patch is based on the latest 2.4.35.3.
> >
> > Performed a lot of tests but only under UHCI controller and ADU200 and all seems to be OK.
> >
> > I would like someone to perform code review as it's my first attempt to the kernel programming.
> > Any comments, propositions are welcome.
>
> At first glance, your backport looks clean. I have one comment however,
> about the author and version. Since it's a backport from an existing
> driver and not one you wrote yourself (eventhough you did the backporting
> work), the MODULE_AUTHOR should not be changed (but I think you can add
> yourself to it after a comma). The version should reflect the version you
> derived it from, at least for bug tracking purposes.

Sounds good for me. Will correct it.

>
> Also, while I understand you would be very glad to get your work merged
> (we all once had our first piece of code), I'd like to mention that you
> seem to be the only user of this hardware under 2.4 (since it is currently
> not supported). I'm not sure it's very reasonable to merge a driver in 2.4
> right now for just one user. Even more, I understand that you finally moved
> to other hardware, so my feeling is that you did this work as an exercice
> (which was cleanly performed, BTW), but that it will not get any real use
> in 2.4.

Yes, I would like it to be merged... But not just to see my name in
the kernel sources.
I'm the only one user of this hardware under 2.4 because it's some
kind of trick to make it work under 2.4 w/o its support in the kernel.
We moved to the other hardware because of our reasons and some
customers can move to the other OS where this hardware will be
supported.
I'm sure that we're not the first who tried to make it work in 2.4.
Original driver was created for 2.5 and > because interrupt out urbs
were not supported in 2.4. Now it's not an issue.

>
> Since 2.4 is moving very slowly, there should be no problem applying
> this patch to any version if you really need to use it. Maybe it would
> even work with your 2.4 enterprise kernel.
>
> Note that I'm not radically opposed to merge support for new drivers.
> If you provide us with really good arguments for a merge, maybe I'll
> change my opinion, but I doubt about it, since the only users of this
> device must currently be running 2.6.

I'm not going to force you to do this, also I can't do this:). But
after going through the recent news where Greg proposed to create
drivers for companies for free it looks really reasonable. I
understand that we are talking about 2.4 but if you will simply run
diff for adutux of 2.4 and 2.6 you will see that changes are really
trivial.
Also IMHO the more drivers are in the tree the more users will use it.
Once it will be merged in the mainline then it will be backported to
enterprise kernels and would gain wide usage.

Best,
Vitaliy

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From: Willy Tarreau <w@...>
Subject: Re: [linux-usb-devel] [2.4 patch] Port of adutux driver from 2.6 kernel to 2.4.
Date: Oct 14, 6:39 pm 2007

On Sun, Oct 14, 2007 at 11:45:36PM +0300, Vitaliy Ivanov wrote:
> > Also, while I understand you would be very glad to get your work merged
> > (we all once had our first piece of code), I'd like to mention that you
> > seem to be the only user of this hardware under 2.4 (since it is currently
> > not supported). I'm not sure it's very reasonable to merge a driver in 2.4
> > right now for just one user. Even more, I understand that you finally moved
> > to other hardware, so my feeling is that you did this work as an exercice
> > (which was cleanly performed, BTW), but that it will not get any real use
> > in 2.4.
> 
> Yes, I would like it to be merged... But not just to see my name in
> the kernel sources.
> I'm the only one user of this hardware under 2.4 because it's some
> kind of trick to make it work under 2.4 w/o its support in the kernel.
> We moved to the other hardware because of our reasons and some
> customers can move to the other OS where this hardware will be
> supported.

But something's strange. If people were using 2.4, this hardware has
never worked for them, right ? Why suddenly would they decide that
they have to switch OS or hardware ? Or maybe this hardware replaces
an old one which was supported ?

> I'm sure that we're not the first who tried to make it work in 2.4.

Perhaps, but if you were the last, interest is pretty limited :-)

> Original driver was created for 2.5 and > because interrupt out urbs
> were not supported in 2.4. Now it's not an issue.
> 
> >
> > Since 2.4 is moving very slowly, there should be no problem applying
> > this patch to any version if you really need to use it. Maybe it would
> > even work with your 2.4 enterprise kernel.
> >
> > Note that I'm not radically opposed to merge support for new drivers.
> > If you provide us with really good arguments for a merge, maybe I'll
> > change my opinion, but I doubt about it, since the only users of this
> > device must currently be running 2.6.
> 
> I'm not going to force you to do this, also I can't do this:). But
> after going through the recent news where Greg proposed to create
> drivers for companies for free it looks really reasonable. I
> understand that we are talking about 2.4 but if you will simply run
> diff for adutux of 2.4 and 2.6 you will see that changes are really
> trivial.

That's what I've seen. I can propose you something (unless someone
else raises his hand saying "no") : you update your patch with a
short description of what the hardware module is supposed to be used
for, and you accept to step up as the maintainer for this backport,
which will imply that you put your name and mail in the MAINTAINERS
file. That way, if you're the only user, nobody will be annoyed, and
if there are other users and some of them have problems, I don't waste
my time on something I don't know at all. If you agree with this deal
(which I think is fair), then I'm willing to merge your patch into
2.4.36-pre.

> Also IMHO the more drivers are in the tree the more users will use it.

Not necessarily. 2.4 is currently used by people who already are in 2.4
and cannot/do not want to switch, and by people who are looking for close
to zero maintenance. Drivers are often a reason to switch away from 2.4,
but not to stay in 2.4.

> Once it will be merged in the mainline then it will be backported to
> enterprise kernels and would gain wide usage.

I don't believe that. Enterprise kernels will not evolve much and will
probably not enable it as long as they have not tested it.

Regards,
Willy


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From: Pete Zaitcev <zaitcev@...>
Subject: Re: [linux-usb-devel] [2.4 patch] Port of adutux driver from 2.6 kernel to 2.4.
Date: Oct 15, 1:30 pm 2007

On Sun, 14 Oct 2007 23:45:36 +0300, "Vitaliy Ivanov" <vitalivanov@gmail.com> wrote:

> Also IMHO the more drivers are in the tree the more users will use it.
> Once it will be merged in the mainline then it will be backported to
> enterprise kernels and would gain wide usage.

At least in case of RHEL, such backports never were automatic. In any
case, RHEL 2.1 and 3 do not receive new drivers anymore. We only do
bugfixes if something comes up. Realistically speaking, 2.4 kernels
are just too old for anyone to use. So, I think it would be best for
you to think in terms of Willy's tree only.

> +	in_end_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
> +	out_end_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);

Did you verify if this works? We use pre-swapped descriptors in 2.4.
I suspect you allocate 256 times more memory than necessary.

> +static void adu_delete(struct adu_device *dev)
> +	kfree(dev);

> +static int adu_release_internal(struct adu_device *dev)
> +	if (dev->udev == NULL) {
> +		adu_delete(dev);

> +static int adu_open(struct inode *inode, struct file *file)
> +	retval = adu_release_internal(dev);
> +	up(&dev->sem);

The above very clearly is a use-after-free, in case the device was
open across a disconnect. Solution: Use minor_table_mutex to lock
dev->open_count instead of dev->sem. There's no rule that the lock
has to live inside the same structure with members it locks.

-- Pete

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