legousbtower.c

优龙2410linux2.6.8内核源代码

/*
 * LEGO USB Tower driver
 *
 * Copyright (C) 2003 David Glance <[e-mail]>
 *               2001-2004 Juergen Stuber <[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 USB Skeleton driver - 0.5
 * Copyright (C) 2001 Greg Kroah-Hartman ([e-mail])
 *
 * History:
 *
 * 2001-10-13 - 0.1 js
 *   - first version
 * 2001-11-03 - 0.2 js
 *   - simplified buffering, one-shot URBs for writing
 * 2001-11-10 - 0.3 js
 *   - removed IOCTL (setting power/mode is more complicated, postponed)
 * 2001-11-28 - 0.4 js
 *   - added vendor commands for mode of operation and power level in open
 * 2001-12-04 - 0.5 js
 *   - set IR mode by default (by oversight 0.4 set VLL mode)
 * 2002-01-11 - 0.5? pcchan
 *   - make read buffer reusable and work around bytes_to_write issue between
 *     uhci and legusbtower
 * 2002-09-23 - 0.52 david ([e-mail])
 *   - imported into lejos project
 *   - changed wake_up to wake_up_interruptible
 *   - changed to use lego0 rather than tower0
 *   - changed dbg() to use __func__ rather than deprecated __FUNCTION__
 * 2003-01-12 - 0.53 david ([e-mail])
 *   - changed read and write to write everything or
 *     timeout (from a patch by Chris Riesen and Brett Thaeler driver)
 *   - added ioctl functionality to set timeouts
 * 2003-07-18 - 0.54 davidgsf ([e-mail])
 *   - initial import into LegoUSB project
 *   - merge of existing LegoUSB.c driver
 * 2003-07-18 - 0.56 davidgsf ([e-mail])
 *   - port to 2.6 style driver
 * 2004-02-29 - 0.6 Juergen Stuber <[e-mail]>
 *   - fix locking
 *   - unlink read URBs which are no longer needed
 *   - allow increased buffer size, eliminates need for timeout on write
 *   - have read URB running continuously
 *   - added poll
 *   - forbid seeking
 *   - added nonblocking I/O
 *   - changed back __func__ to __FUNCTION__
 *   - read and log tower firmware version
 *   - reset tower on probe, avoids failure of first write
 * 2004-03-09 - 0.7 Juergen Stuber <[e-mail]>
 *   - timeout read now only after inactivity, shorten default accordingly
 * 2004-03-11 - 0.8 Juergen Stuber <[e-mail]>
 *   - log major, minor instead of possibly confusing device filename
 *   - whitespace cleanup
 * 2004-03-12 - 0.9 Juergen Stuber <[e-mail]>
 *   - normalize whitespace in debug messages
 *   - take care about endianness in control message responses
 * 2004-03-13 - 0.91 Juergen Stuber <[e-mail]>
 *   - make default intervals longer to accommodate current EHCI driver
 * 2004-03-19 - 0.92 Juergen Stuber <[e-mail]>
 *   - replaced atomic_t by memory barriers
 * 2004-04-21 - 0.93 Juergen Stuber <[e-mail]>
 *   - wait for completion of write urb in release (needed for remotecontrol)
 *   - corrected poll for write direction (missing negation)
 * 2004-04-22 - 0.94 Juergen Stuber <[e-mail]>
 *   - make device locking interruptible
 * 2004-04-30 - 0.95 Juergen Stuber <[e-mail]>
 *   - check for valid udev on resubmitting and unlinking urbs
 */

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


#ifdef CONFIG_USB_DEBUG
	static int debug = 4;
#else
	static int debug = 0;
#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 "v0.95"
#define DRIVER_AUTHOR "Juergen Stuber <[e-mail]>"
#define DRIVER_DESC "LEGO USB Tower Driver"

/* Module parameters */
MODULE_PARM(debug, "i");
MODULE_PARM_DESC(debug, "Debug enabled or not");

/* The defaults are chosen to work with the latest versions of leJOS and NQC.
 */

/* Some legacy software likes to receive packets in one piece.
 * In this case read_buffer_size should exceed the maximal packet length
 * (417 for datalog uploads), and packet_timeout should be set.
 */
static size_t read_buffer_size = 480;
MODULE_PARM(read_buffer_size, "i");
MODULE_PARM_DESC(read_buffer_size, "Read buffer size");

/* Some legacy software likes to send packets in one piece.
 * In this case write_buffer_size should exceed the maximal packet length
 * (417 for firmware and program downloads).
 * A problem with long writes is that the following read may time out
 * if the software is not prepared to wait long enough.
 */
static size_t write_buffer_size = 480;
MODULE_PARM(write_buffer_size, "i");
MODULE_PARM_DESC(write_buffer_size, "Write buffer size");

/* Some legacy software expects reads to contain whole LASM packets.
 * To achieve this, characters which arrive before a packet timeout
 * occurs will be returned in a single read operation.
 * A problem with long reads is that the software may time out
 * if it is not prepared to wait long enough.
 * The packet timeout should be greater than the time between the
 * reception of subsequent characters, which should arrive about
 * every 5ms for the standard 2400 baud.
 * Set it to 0 to disable.
 */
static int packet_timeout = 50;
MODULE_PARM(packet_timeout, "i");
MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");

/* Some legacy software expects blocking reads to time out.
 * Timeout occurs after the specified time of read and write inactivity.
 * Set it to 0 to disable.
 */
static int read_timeout = 200;
MODULE_PARM(read_timeout, "i");
MODULE_PARM_DESC(read_timeout, "Read timeout in ms");

/* 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 8ms for out transfers,
 * which is fast enough for 2400 baud and allows a small additional load.
 * Increase the interval to allow more devices that do interrupt transfers,
 * or set to 0 to use the standard interval from the endpoint descriptors.
 */
static int interrupt_in_interval = 2;
MODULE_PARM(interrupt_in_interval, "i");
MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");

static int interrupt_out_interval = 8;
MODULE_PARM(interrupt_out_interval, "i");
MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");

/* Define these values to match your device */
#define LEGO_USB_TOWER_VENDOR_ID	0x0694
#define LEGO_USB_TOWER_PRODUCT_ID	0x0001

/* Vendor requests */
#define LEGO_USB_TOWER_REQUEST_RESET		0x04
#define LEGO_USB_TOWER_REQUEST_GET_VERSION	0xFD

struct tower_reset_reply {
	__u16 size;		/* little-endian */
	__u8 err_code;
	__u8 spare;
} __attribute__ ((packed));

struct tower_get_version_reply {
	__u16 size;		/* little-endian */
	__u8 err_code;
	__u8 spare;
	__u8 major;
	__u8 minor;
	__u16 build_no;		/* little-endian */
} __attribute__ ((packed));


/* table of devices that work with this driver */
static struct usb_device_id tower_table [] = {
	{ USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
	{ }					/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, tower_table);

#define LEGO_USB_TOWER_MINOR_BASE	160


/* Structure to hold all of our device specific stuff */
struct lego_usb_tower {
	struct semaphore	sem;		/* locks this structure */
	struct usb_device*	udev;		/* save off the usb device pointer */
	unsigned char		minor;		/* the starting minor number for this device */

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

	char*			read_buffer;
	size_t			read_buffer_length; /* this much came in */
	size_t			read_packet_length; /* this much will be returned on read */
	spinlock_t		read_buffer_lock;
	int			packet_timeout_jiffies;
	unsigned long		read_last_arrival;

	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;
	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;
	int			interrupt_out_busy;

};


/* local function prototypes */
static ssize_t tower_read	(struct file *file, char __user *buffer, size_t count, loff_t *ppos);
static ssize_t tower_write	(struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
static inline void tower_delete (struct lego_usb_tower *dev);
static int tower_open		(struct inode *inode, struct file *file);
static int tower_release	(struct inode *inode, struct file *file);
static unsigned int tower_poll	(struct file *file, poll_table *wait);
static loff_t tower_llseek	(struct file *file, loff_t off, int whence);

static void tower_abort_transfers (struct lego_usb_tower *dev);
static void tower_check_for_read_packet (struct lego_usb_tower *dev);
static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs);
static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs);

static int  tower_probe	(struct usb_interface *interface, const struct usb_device_id *id);
static void tower_disconnect	(struct usb_interface *interface);


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

/* file operations needed when we register this driver */
static struct file_operations tower_fops = {
	.owner =	THIS_MODULE,
	.read  =	tower_read,
	.write =	tower_write,
	.open =		tower_open,
	.release =	tower_release,
	.poll =		tower_poll,
	.llseek =	tower_llseek,
};

/*
 * usb class driver info in order to get a minor number from the usb core,
 * and to have the device registered with devfs and the driver core
 */
static struct usb_class_driver tower_class = {
	.name =		"usb/legousbtower%d",
	.fops =		&tower_fops,
	.mode =		S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH,
	.minor_base =	LEGO_USB_TOWER_MINOR_BASE,
};


/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver tower_driver = {
	.owner =	THIS_MODULE,
	.name =		"legousbtower",
	.probe =	tower_probe,
	.disconnect =	tower_disconnect,
	.id_table =	tower_table,
};


/**
 *	lego_usb_tower_debug_data
 */
static inline void lego_usb_tower_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");
}


/**
 *	tower_delete
 */
static inline void tower_delete (struct lego_usb_tower *dev)
{
	dbg(2, "%s: enter", __FUNCTION__);

	tower_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);
	}
	kfree (dev->read_buffer);
	kfree (dev->interrupt_in_buffer);
	kfree (dev->interrupt_out_buffer);
	kfree (dev);

	dbg(2, "%s: leave", __FUNCTION__);
}


/**
 *	tower_open
 */
static int tower_open (struct inode *inode, struct file *file)
{
	struct lego_usb_tower *dev = NULL;
	int subminor;
	int retval = 0;
	struct usb_interface *interface;

	dbg(2, "%s: enter", __FUNCTION__);

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

	down (&disconnect_sem);

	interface = usb_find_interface (&tower_driver, subminor);

	if (!interface) {
		err ("%s - error, can't find device for minor %d",
		     __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->read_buffer_length = 0;
	dev->read_packet_length = 0;
	usb_fill_int_urb (dev->interrupt_in_urb,
			  dev->udev,
			  usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
			  dev->interrupt_in_buffer,
			  dev->interrupt_in_endpoint->wMaxPacketSize,
			  tower_interrupt_in_callback,
			  dev,
			  dev->interrupt_in_interval);

	dev->interrupt_in_running = 1;
	dev->interrupt_in_done = 0;
	mb();

	retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
	if (retval) {
		err("Couldn't submit interrupt_in_urb %d", 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);

	dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);

	return retval;
}

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

	dbg(2, "%s: enter", __FUNCTION__);

	dev = (struct lego_usb_tower *)file->private_data;

	if (dev == NULL) {
		dbg(1, "%s: object is NULL", __FUNCTION__);
		retval = -ENODEV;
		goto exit;
	}

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

	if (dev->open_count != 1) {
		dbg(1, "%s: device not opened exactly once", __FUNCTION__);
		retval = -ENODEV;
		goto unlock_exit;
	}
	if (dev->udev == NULL) {
		/* the device was unplugged before the file was released */
		up (&dev->sem);	/* unlock here as tower_delete frees dev */
		tower_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);
	}
	tower_abort_transfers (dev);
	dev->open_count = 0;

unlock_exit:
	up (&dev->sem);

exit:
	dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
	return retval;
}


/**
 *	tower_abort_transfers
 *      aborts transfers and frees associated data structures
 */
static void tower_abort_transfers (struct lego_usb_tower *dev)
{
	dbg(2, "%s: enter", __FUNCTION__);

	if (dev == NULL) {
		dbg(1, "%s: dev is null", __FUNCTION__);
		goto exit;
	}

	/* shutdown transfer */
	if (dev->interrupt_in_running) {
		dev->interrupt_in_running = 0;
		mb();
		if (dev->interrupt_in_urb != NULL && dev->udev) {
			usb_unlink_urb (dev->interrupt_in_urb);
		}
	}
	if (dev->interrupt_out_busy) {
		if (dev->interrupt_out_urb != NULL && dev->udev) {
			usb_unlink_urb (dev->interrupt_out_urb);
		}
	}

exit:
	dbg(2, "%s: leave", __FUNCTION__);
}


/**
 *	tower_check_for_read_packet
 *
 *      To get correct semantics for signals and non-blocking I/O
 *      with packetizing we pretend not to see any data in the read buffer
 *      until it has been there unchanged for at least
 *      dev->packet_timeout_jiffies, or until the buffer is full.
 */
static void tower_check_for_read_packet (struct lego_usb_tower *dev)
{
	spin_lock_irq (&dev->read_buffer_lock);
	if (!packet_timeout
	    || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
	    || dev->read_buffer_length == read_buffer_size) {
		dev->read_packet_length = dev->read_buffer_length;
	}
	dev->interrupt_in_done = 0;
	spin_unlock_irq (&dev->read_buffer_lock);
}


/**
 *	tower_poll
 */
static unsigned int tower_poll (struct file *file, poll_table *wait)
{
	struct lego_usb_tower *dev;
	unsigned int mask = 0;

	dbg(2, "%s: enter", __FUNCTION__);

	dev = file->private_data;

	poll_wait(file, &dev->read_wait, wait);
	poll_wait(file, &dev->write_wait, wait);

	tower_check_for_read_packet(dev);
	if (dev->read_packet_length > 0) {
		mask |= POLLIN | POLLRDNORM;
	}
	if (!dev->interrupt_out_busy) {
		mask |= POLLOUT | POLLWRNORM;
	}

	dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);