iowarrior.c

linux 内核源代码

/*
 *  Native support for the I/O-Warrior USB devices
 *
 *  Copyright (c) 2003-2005  Code Mercenaries GmbH
 *  written by Christian Lucht <[e-mail]>
 *
 *  based on

 *  usb-skeleton.c by Greg Kroah-Hartman  <[e-mail]>
 *  brlvger.c by Stephane Dalton  <[e-mail]>
 *           and St�hane Doyon   <[e-mail]>
 *
 *  Released under the GPLv2.
 */

#include <linux/module.h>
#include <linux/usb.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/version.h>
#include <linux/usb/iowarrior.h>

/* Version Information */
#define DRIVER_VERSION "v0.4.0"
#define DRIVER_AUTHOR "Christian Lucht <[e-mail]>"
#define DRIVER_DESC "USB IO-Warrior driver (Linux 2.6.x)"

#define USB_VENDOR_ID_CODEMERCS		1984
/* low speed iowarrior */
#define USB_DEVICE_ID_CODEMERCS_IOW40	0x1500
#define USB_DEVICE_ID_CODEMERCS_IOW24	0x1501
#define USB_DEVICE_ID_CODEMERCS_IOWPV1	0x1511
#define USB_DEVICE_ID_CODEMERCS_IOWPV2	0x1512
/* full speed iowarrior */
#define USB_DEVICE_ID_CODEMERCS_IOW56	0x1503

/* Get a minor range for your devices from the usb maintainer */
#ifdef CONFIG_USB_DYNAMIC_MINORS
#define IOWARRIOR_MINOR_BASE	0
#else
#define IOWARRIOR_MINOR_BASE	208	// SKELETON_MINOR_BASE 192 + 16, not offical yet
#endif

/* interrupt input queue size */
#define MAX_INTERRUPT_BUFFER 16
/*
   maximum number of urbs that are submitted for writes at the same time,
   this applies to the IOWarrior56 only!
   IOWarrior24 and IOWarrior40 use synchronous usb_control_msg calls.
*/
#define MAX_WRITES_IN_FLIGHT 4

/* Use our own dbg macro */
#undef dbg
#define dbg( format, arg... ) do { if( debug ) printk( KERN_DEBUG __FILE__ ": " format "\n" , ## arg ); } while ( 0 )

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/* Module parameters */
static int debug = 0;
module_param(debug, bool, 0644);
MODULE_PARM_DESC(debug, "debug=1 enables debugging messages");

static struct usb_driver iowarrior_driver;
static DEFINE_MUTEX(iowarrior_open_disc_lock);

/*--------------*/
/*     data     */
/*--------------*/

/* Structure to hold all of our device specific stuff */
struct iowarrior {
	struct mutex mutex;			/* locks this structure */
	struct usb_device *udev;		/* save off the usb device pointer */
	struct usb_interface *interface;	/* the interface for this device */
	unsigned char minor;			/* the starting minor number for this device */
	struct usb_endpoint_descriptor *int_out_endpoint;	/* endpoint for reading (needed for IOW56 only) */
	struct usb_endpoint_descriptor *int_in_endpoint;	/* endpoint for reading */
	struct urb *int_in_urb;		/* the urb for reading data */
	unsigned char *int_in_buffer;	/* buffer for data to be read */
	unsigned char serial_number;	/* to detect lost packages */
	unsigned char *read_queue;	/* size is MAX_INTERRUPT_BUFFER * packet size */
	wait_queue_head_t read_wait;
	wait_queue_head_t write_wait;	/* wait-queue for writing to the device */
	atomic_t write_busy;		/* number of write-urbs submitted */
	atomic_t read_idx;
	atomic_t intr_idx;
	spinlock_t intr_idx_lock;	/* protects intr_idx */
	atomic_t overflow_flag;		/* signals an index 'rollover' */
	int present;			/* this is 1 as long as the device is connected */
	int opened;			/* this is 1 if the device is currently open */
	char chip_serial[9];		/* the serial number string of the chip connected */
	int report_size;		/* number of bytes in a report */
	u16 product_id;
};

/*--------------*/
/*    globals   */
/*--------------*/

/*
 *  USB spec identifies 5 second timeouts.
 */
#define GET_TIMEOUT 5
#define USB_REQ_GET_REPORT  0x01
//#if 0
static int usb_get_report(struct usb_device *dev,
			  struct usb_host_interface *inter, unsigned char type,
			  unsigned char id, void *buf, int size)
{
	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
			       USB_REQ_GET_REPORT,
			       USB_DIR_IN | USB_TYPE_CLASS |
			       USB_RECIP_INTERFACE, (type << 8) + id,
			       inter->desc.bInterfaceNumber, buf, size,
			       GET_TIMEOUT*HZ);
}
//#endif

#define USB_REQ_SET_REPORT 0x09

static int usb_set_report(struct usb_interface *intf, unsigned char type,
			  unsigned char id, void *buf, int size)
{
	return usb_control_msg(interface_to_usbdev(intf),
			       usb_sndctrlpipe(interface_to_usbdev(intf), 0),
			       USB_REQ_SET_REPORT,
			       USB_TYPE_CLASS | USB_RECIP_INTERFACE,
			       (type << 8) + id,
			       intf->cur_altsetting->desc.bInterfaceNumber, buf,
			       size, HZ);
}

/*---------------------*/
/* driver registration */
/*---------------------*/
/* table of devices that work with this driver */
static struct usb_device_id iowarrior_ids[] = {
	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
	{}			/* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, iowarrior_ids);

/*
 * USB callback handler for reading data
 */
static void iowarrior_callback(struct urb *urb)
{
	struct iowarrior *dev = (struct iowarrior *)urb->context;
	int intr_idx;
	int read_idx;
	int aux_idx;
	int offset;
	int status = urb->status;
	int retval;

	switch (status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		return;
	default:
		goto exit;
	}

	spin_lock(&dev->intr_idx_lock);
	intr_idx = atomic_read(&dev->intr_idx);
	/* aux_idx become previous intr_idx */
	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
	read_idx = atomic_read(&dev->read_idx);

	/* queue is not empty and it's interface 0 */
	if ((intr_idx != read_idx)
	    && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
		/* + 1 for serial number */
		offset = aux_idx * (dev->report_size + 1);
		if (!memcmp
		    (dev->read_queue + offset, urb->transfer_buffer,
		     dev->report_size)) {
			/* equal values on interface 0 will be ignored */
			spin_unlock(&dev->intr_idx_lock);
			goto exit;
		}
	}

	/* aux_idx become next intr_idx */
	aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
	if (read_idx == aux_idx) {
		/* queue full, dropping oldest input */
		read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
		atomic_set(&dev->read_idx, read_idx);
		atomic_set(&dev->overflow_flag, 1);
	}

	/* +1 for serial number */
	offset = intr_idx * (dev->report_size + 1);
	memcpy(dev->read_queue + offset, urb->transfer_buffer,
	       dev->report_size);
	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;

	atomic_set(&dev->intr_idx, aux_idx);
	spin_unlock(&dev->intr_idx_lock);
	/* tell the blocking read about the new data */
	wake_up_interruptible(&dev->read_wait);

exit:
	retval = usb_submit_urb(urb, GFP_ATOMIC);
	if (retval)
		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d\n",
			__FUNCTION__, retval);

}

/*
 * USB Callback handler for write-ops
 */
static void iowarrior_write_callback(struct urb *urb)
{
	struct iowarrior *dev;
	int status = urb->status;

	dev = (struct iowarrior *)urb->context;
	/* sync/async unlink faults aren't errors */
	if (status &&
	    !(status == -ENOENT ||
	      status == -ECONNRESET || status == -ESHUTDOWN)) {
		dbg("%s - nonzero write bulk status received: %d",
		    __func__, status);
	}
	/* free up our allocated buffer */
	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
			urb->transfer_buffer, urb->transfer_dma);
	/* tell a waiting writer the interrupt-out-pipe is available again */
	atomic_dec(&dev->write_busy);
	wake_up_interruptible(&dev->write_wait);
}

/**
 *	iowarrior_delete
 */
static inline void iowarrior_delete(struct iowarrior *dev)
{
	dbg("%s - minor %d", __func__, dev->minor);
	kfree(dev->int_in_buffer);
	usb_free_urb(dev->int_in_urb);
	kfree(dev->read_queue);
	kfree(dev);
}

/*---------------------*/
/* fops implementation */
/*---------------------*/

static int read_index(struct iowarrior *dev)
{
	int intr_idx, read_idx;

	read_idx = atomic_read(&dev->read_idx);
	intr_idx = atomic_read(&dev->intr_idx);

	return (read_idx == intr_idx ? -1 : read_idx);
}

/**
 *  iowarrior_read
 */
static ssize_t iowarrior_read(struct file *file, char __user *buffer,
			      size_t count, loff_t *ppos)
{
	struct iowarrior *dev;
	int read_idx;
	int offset;

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

	/* verify that the device wasn't unplugged */
	if (dev == NULL || !dev->present)
		return -ENODEV;

	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);

	/* read count must be packet size (+ time stamp) */
	if ((count != dev->report_size)
	    && (count != (dev->report_size + 1)))
		return -EINVAL;

	/* repeat until no buffer overrun in callback handler occur */
	do {
		atomic_set(&dev->overflow_flag, 0);
		if ((read_idx = read_index(dev)) == -1) {
			/* queue emty */
			if (file->f_flags & O_NONBLOCK)
				return -EAGAIN;
			else {
				//next line will return when there is either new data, or the device is unplugged
				int r = wait_event_interruptible(dev->read_wait,
								 (!dev->present
								  || (read_idx =
								      read_index
								      (dev)) !=
								  -1));
				if (r) {
					//we were interrupted by a signal
					return -ERESTART;
				}
				if (!dev->present) {
					//The device was unplugged
					return -ENODEV;
				}
				if (read_idx == -1) {
					// Can this happen ???
					return 0;
				}
			}
		}

		offset = read_idx * (dev->report_size + 1);
		if (copy_to_user(buffer, dev->read_queue + offset, count)) {
			return -EFAULT;
		}
	} while (atomic_read(&dev->overflow_flag));

	read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
	atomic_set(&dev->read_idx, read_idx);
	return count;
}

/*
 * iowarrior_write
 */
static ssize_t iowarrior_write(struct file *file,
			       const char __user *user_buffer,
			       size_t count, loff_t *ppos)
{
	struct iowarrior *dev;
	int retval = 0;
	char *buf = NULL;	/* for IOW24 and IOW56 we need a buffer */
	struct urb *int_out_urb = NULL;

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

	mutex_lock(&dev->mutex);
	/* verify that the device wasn't unplugged */
	if (!dev->present) {
		retval = -ENODEV;
		goto exit;
	}
	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
	/* if count is 0 we're already done */
	if (count == 0) {
		retval = 0;
		goto exit;
	}
	/* We only accept full reports */
	if (count != dev->report_size) {
		retval = -EINVAL;
		goto exit;
	}
	switch (dev->product_id) {
	case USB_DEVICE_ID_CODEMERCS_IOW24:
	case USB_DEVICE_ID_CODEMERCS_IOWPV1:
	case USB_DEVICE_ID_CODEMERCS_IOWPV2:
	case USB_DEVICE_ID_CODEMERCS_IOW40:
		/* IOW24 and IOW40 use a synchronous call */
		buf = kmalloc(8, GFP_KERNEL);	/* 8 bytes are enough for both products */
		if (!buf) {
			retval = -ENOMEM;
			goto exit;
		}
		if (copy_from_user(buf, user_buffer, count)) {
			retval = -EFAULT;
			kfree(buf);
			goto exit;
		}
		retval = usb_set_report(dev->interface, 2, 0, buf, count);
		kfree(buf);
		goto exit;
		break;
	case USB_DEVICE_ID_CODEMERCS_IOW56:
		/* The IOW56 uses asynchronous IO and more urbs */
		if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
			/* Wait until we are below the limit for submitted urbs */
			if (file->f_flags & O_NONBLOCK) {
				retval = -EAGAIN;
				goto exit;
			} else {
				retval = wait_event_interruptible(dev->write_wait,
								  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
				if (retval) {
					/* we were interrupted by a signal */
					retval = -ERESTART;
					goto exit;
				}
				if (!dev->present) {
					/* The device was unplugged */
					retval = -ENODEV;
					goto exit;
				}
				if (!dev->opened) {
					/* We were closed while waiting for an URB */
					retval = -ENODEV;
					goto exit;
				}
			}
		}
		atomic_inc(&dev->write_busy);
		int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
		if (!int_out_urb) {
			retval = -ENOMEM;
			dbg("%s Unable to allocate urb ", __func__);
			goto error_no_urb;
		}
		buf = usb_buffer_alloc(dev->udev, dev->report_size,
				       GFP_KERNEL, &int_out_urb->transfer_dma);
		if (!buf) {
			retval = -ENOMEM;
			dbg("%s Unable to allocate buffer ", __func__);
			goto error_no_buffer;
		}
		usb_fill_int_urb(int_out_urb, dev->udev,
				 usb_sndintpipe(dev->udev,
						dev->int_out_endpoint->bEndpointAddress),
				 buf, dev->report_size,
				 iowarrior_write_callback, dev,
				 dev->int_out_endpoint->bInterval);
		int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
		if (copy_from_user(buf, user_buffer, count)) {
			retval = -EFAULT;
			goto error;
		}
		retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
		if (retval) {
			dbg("%s submit error %d for urb nr.%d", __func__,
			    retval, atomic_read(&dev->write_busy));
			goto error;
		}
		/* submit was ok */
		retval = count;
		usb_free_urb(int_out_urb);
		goto exit;
		break;
	default:
		/* what do we have here ? An unsupported Product-ID ? */
		dev_err(&dev->interface->dev, "%s - not supported for product=0x%x\n",
			__FUNCTION__, dev->product_id);
		retval = -EFAULT;
		goto exit;
		break;
	}
error:
	usb_buffer_free(dev->udev, dev->report_size, buf,
			int_out_urb->transfer_dma);
error_no_buffer: