ldusb.c

linux-2.6.15.6

/**
 * Generic USB driver for report based interrupt in/out devices
 * like LD Didactic's USB devices. LD Didactic's USB devices are
 * HID devices which do not use HID report definitons (they use
 * raw interrupt in and our reports only for communication).
 *
 * This driver uses a ring buffer for time critical reading of
 * interrupt in reports and provides read and write methods for
 * raw interrupt reports (similar to the Windows HID driver).
 * Devices based on the book USB COMPLETE by Jan Axelson may need
 * such a compatibility to the Windows HID driver.
 *
 * Copyright (C) 2005 Michael Hund <[e-mail]>
 *
 *	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 Lego USB Tower driver
 * Copyright (C) 2003 David Glance <[e-mail]>
 *		 2001-2004 Juergen Stuber <[e-mail]>
 *
 * V0.1  (mh) Initial version
 * V0.11 (mh) Added raw support for HID 1.0 devices (no interrupt out endpoint)
 * V0.12 (mh) Added kmalloc check for string buffer
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>

#include <asm/uaccess.h>
#include <linux/input.h>
#include <linux/usb.h>
#include <linux/poll.h>

/* Define these values to match your devices */
#define USB_VENDOR_ID_LD		0x0f11	/* USB Vendor ID of LD Didactic GmbH */
#define USB_DEVICE_ID_CASSY		0x1000	/* USB Product ID for all CASSY-S modules */
#define USB_DEVICE_ID_POCKETCASSY	0x1010	/* USB Product ID for Pocket-CASSY */
#define USB_DEVICE_ID_MOBILECASSY	0x1020	/* USB Product ID for Mobile-CASSY */
#define USB_DEVICE_ID_JWM		0x1080	/* USB Product ID for Joule and Wattmeter */
#define USB_DEVICE_ID_DMMP		0x1081	/* USB Product ID for Digital Multimeter P (reserved) */
#define USB_DEVICE_ID_UMIP		0x1090	/* USB Product ID for UMI P */
#define USB_DEVICE_ID_VIDEOCOM		0x1200	/* USB Product ID for VideoCom */
#define USB_DEVICE_ID_COM3LAB		0x2000	/* USB Product ID for COM3LAB */
#define USB_DEVICE_ID_TELEPORT		0x2010	/* USB Product ID for Terminal Adapter */
#define USB_DEVICE_ID_NETWORKANALYSER	0x2020	/* USB Product ID for Network Analyser */
#define USB_DEVICE_ID_POWERCONTROL	0x2030	/* USB Product ID for Controlling device for Power Electronics */

#define USB_VENDOR_ID_VERNIER		0x08f7
#define USB_DEVICE_ID_VERNIER_LABPRO	0x0001
#define USB_DEVICE_ID_VERNIER_GOTEMP	0x0002
#define USB_DEVICE_ID_VERNIER_SKIP	0x0003
#define USB_DEVICE_ID_VERNIER_CYCLOPS	0x0004


#ifdef CONFIG_USB_DYNAMIC_MINORS
#define USB_LD_MINOR_BASE	0
#else
#define USB_LD_MINOR_BASE	176
#endif

/* table of devices that work with this driver */
static struct usb_device_id ld_usb_table [] = {
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_CASSY) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_POCKETCASSY) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_MOBILECASSY) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_JWM) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_DMMP) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_UMIP) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_VIDEOCOM) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_COM3LAB) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_TELEPORT) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_NETWORKANALYSER) },
	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_POWERCONTROL) },
	{ USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_LABPRO) },
	{ USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_GOTEMP) },
	{ USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_SKIP) },
	{ USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_CYCLOPS) },
	{ }					/* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, ld_usb_table);
MODULE_VERSION("V0.12");
MODULE_AUTHOR("Michael Hund <[e-mail]>");
MODULE_DESCRIPTION("LD USB Driver");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("LD USB Devices");

#ifdef CONFIG_USB_DEBUG
	static int debug = 1;
#else
	static int debug = 0;
#endif

/* Use our own dbg macro */
#define dbg_info(dev, format, arg...) do { if (debug) dev_info(dev , format , ## arg); } while (0)

/* Module parameters */
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");

/* All interrupt in transfers are collected in a ring buffer to
 * avoid racing conditions and get better performance of the driver.
 */
static int ring_buffer_size = 128;
module_param(ring_buffer_size, int, 0);
MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");

/* The write_buffer can contain more than one interrupt out transfer.
 */
static int write_buffer_size = 10;
module_param(write_buffer_size, int, 0);
MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");

/* As of kernel version 2.6.4 ehci-hcd uses an
 * "only one interrupt transfer per frame" shortcut
 * to simplify the scheduling of periodic transfers.
 * This conflicts with our standard 1ms intervals for in and out URBs.
 * We use default intervals of 2ms for in and 2ms for out transfers,
 * which should be fast enough.
 * Increase the interval to allow more devices that do interrupt transfers,
 * or set to 1 to use the standard interval from the endpoint descriptors.
 */
static int min_interrupt_in_interval = 2;
module_param(min_interrupt_in_interval, int, 0);
MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");

static int min_interrupt_out_interval = 2;
module_param(min_interrupt_out_interval, int, 0);
MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");

/* Structure to hold all of our device specific stuff */
struct ld_usb {
	struct semaphore	sem;		/* locks this structure */
	struct usb_interface*	intf;		/* save off the usb interface pointer */

	int			open_count;	/* number of times this port has been opened */

	char*			ring_buffer;
	unsigned int		ring_head;
	unsigned int		ring_tail;

	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			interrupt_in_interval;
	size_t			interrupt_in_endpoint_size;
	int			interrupt_in_running;
	int			interrupt_in_done;

	char*			interrupt_out_buffer;
	struct usb_endpoint_descriptor* interrupt_out_endpoint;
	struct urb*		interrupt_out_urb;
	int			interrupt_out_interval;
	size_t			interrupt_out_endpoint_size;
	int			interrupt_out_busy;
};

/* prevent races between open() and disconnect() */
static DECLARE_MUTEX(disconnect_sem);

static struct usb_driver ld_usb_driver;

/**
 *	ld_usb_abort_transfers
 *      aborts transfers and frees associated data structures
 */
static void ld_usb_abort_transfers(struct ld_usb *dev)
{
	/* shutdown transfer */
	if (dev->interrupt_in_running) {
		dev->interrupt_in_running = 0;
		if (dev->intf)
			usb_kill_urb(dev->interrupt_in_urb);
	}
	if (dev->interrupt_out_busy)
		if (dev->intf)
			usb_kill_urb(dev->interrupt_out_urb);
}

/**
 *	ld_usb_delete
 */
static void ld_usb_delete(struct ld_usb *dev)
{
	ld_usb_abort_transfers(dev);

	/* free data structures */
	usb_free_urb(dev->interrupt_in_urb);
	usb_free_urb(dev->interrupt_out_urb);
	kfree(dev->ring_buffer);
	kfree(dev->interrupt_in_buffer);
	kfree(dev->interrupt_out_buffer);
	kfree(dev);
}

/**
 *	ld_usb_interrupt_in_callback
 */
static void ld_usb_interrupt_in_callback(struct urb *urb, struct pt_regs *regs)
{
	struct ld_usb *dev = urb->context;
	size_t *actual_buffer;
	unsigned int next_ring_head;
	int retval;

	if (urb->status) {
		if (urb->status == -ENOENT ||
		    urb->status == -ECONNRESET ||
		    urb->status == -ESHUTDOWN) {
			goto exit;
		} else {
			dbg_info(&dev->intf->dev, "%s: nonzero status received: %d\n",
				 __FUNCTION__, urb->status);
			goto resubmit; /* maybe we can recover */
		}
	}

	if (urb->actual_length > 0) {
		next_ring_head = (dev->ring_head+1) % ring_buffer_size;
		if (next_ring_head != dev->ring_tail) {
			actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_head*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
			/* actual_buffer gets urb->actual_length + interrupt_in_buffer */
			*actual_buffer = urb->actual_length;
			memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
			dev->ring_head = next_ring_head;
			dbg_info(&dev->intf->dev, "%s: received %d bytes\n",
				 __FUNCTION__, urb->actual_length);
		} else
			dev_warn(&dev->intf->dev,
				 "Ring buffer overflow, %d bytes dropped\n",
				 urb->actual_length);
	}

resubmit:
	/* resubmit if we're still running */
	if (dev->interrupt_in_running && dev->intf) {
		retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
		if (retval)
			dev_err(&dev->intf->dev,
				"usb_submit_urb failed (%d)\n", retval);
	}

exit:
	dev->interrupt_in_done = 1;
	wake_up_interruptible(&dev->read_wait);
}

/**
 *	ld_usb_interrupt_out_callback
 */
static void ld_usb_interrupt_out_callback(struct urb *urb, struct pt_regs *regs)
{
	struct ld_usb *dev = urb->context;

	/* sync/async unlink faults aren't errors */
	if (urb->status && !(urb->status == -ENOENT ||
			     urb->status == -ECONNRESET ||
			     urb->status == -ESHUTDOWN))
		dbg_info(&dev->intf->dev,
			 "%s - nonzero write interrupt status received: %d\n",
			 __FUNCTION__, urb->status);

	dev->interrupt_out_busy = 0;
	wake_up_interruptible(&dev->write_wait);
}

/**
 *	ld_usb_open
 */
static int ld_usb_open(struct inode *inode, struct file *file)
{
	struct ld_usb *dev;
	int subminor;
	int retval = 0;
	struct usb_interface *interface;

	nonseekable_open(inode, file);
	subminor = iminor(inode);

	down(&disconnect_sem);

	interface = usb_find_interface(&ld_usb_driver, subminor);

	if (!interface) {
		err("%s - error, can't find device for minor %d\n",
		     __FUNCTION__, subminor);
		retval = -ENODEV;
		goto unlock_disconnect_exit;
	}

	dev = usb_get_intfdata(interface);

	if (!dev) {
		retval = -ENODEV;
		goto unlock_disconnect_exit;
	}

	/* lock this device */
	if (down_interruptible(&dev->sem)) {
		retval = -ERESTARTSYS;
		goto unlock_disconnect_exit;
	}

	/* allow opening only once */
	if (dev->open_count) {
		retval = -EBUSY;
		goto unlock_exit;
	}
	dev->open_count = 1;

	/* initialize in direction */
	dev->ring_head = 0;
	dev->ring_tail = 0;
	usb_fill_int_urb(dev->interrupt_in_urb,
			 interface_to_usbdev(interface),
			 usb_rcvintpipe(interface_to_usbdev(interface),
					dev->interrupt_in_endpoint->bEndpointAddress),
			 dev->interrupt_in_buffer,
			 dev->interrupt_in_endpoint_size,
			 ld_usb_interrupt_in_callback,
			 dev,
			 dev->interrupt_in_interval);

	dev->interrupt_in_running = 1;
	dev->interrupt_in_done = 0;

	retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
	if (retval) {
		dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
		dev->interrupt_in_running = 0;
		dev->open_count = 0;
		goto unlock_exit;
	}

	/* save device in the file's private structure */
	file->private_data = dev;

unlock_exit:
	up(&dev->sem);

unlock_disconnect_exit:
	up(&disconnect_sem);

	return retval;
}

/**
 *	ld_usb_release
 */
static int ld_usb_release(struct inode *inode, struct file *file)
{
	struct ld_usb *dev;
	int retval = 0;

	dev = file->private_data;

	if (dev == NULL) {
		retval = -ENODEV;
		goto exit;
	}

	if (down_interruptible(&dev->sem)) {
		retval = -ERESTARTSYS;
		goto exit;
	}

	if (dev->open_count != 1) {
		retval = -ENODEV;
		goto unlock_exit;
	}
	if (dev->intf == NULL) {
		/* the device was unplugged before the file was released */
		up(&dev->sem);
		/* unlock here as ld_usb_delete frees dev */
		ld_usb_delete(dev);
		goto exit;
	}

	/* wait until write transfer is finished */
	if (dev->interrupt_out_busy)
		wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
	ld_usb_abort_transfers(dev);
	dev->open_count = 0;

unlock_exit:
	up(&dev->sem);

exit:
	return retval;
}