garmin USB: linux USB host驅動

以garmin usb為例：

1）編譯生成garmin_usb.ko檔案，使用insmod命令安裝模組

2）使用lsmod命令可檢視核心已經安裝好模組：garmin_usb

3）插入USB裝置後，使用ls /dev，會發現多了skel0裝置節點檔案（該裝置檔案在代 碼中使用device_create()自動產生，不需要再單獨使用mknod命令產生）

4）編寫應用程式，使用open、read、write來操作讀寫資料

 

注： device端需要有相應的端點描述符。否者在probe過程中會失敗。

 

原始碼：

1. garmin_usb.c

/*
 * USB Skeleton driver - 2.2
 *
 * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
 *
 *	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, version 2.
 *
 * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
 * but has been rewritten to be easier to read and use.
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
#include <asm/uaccess.h>
#include <linux/usb.h>
#include <linux/mutex.h>

#define info printk

/* Define these values to match your devices */
#define USB_SKEL_VENDOR_ID	0x0471
#define USB_SKEL_PRODUCT_ID	0x0999

#if 1 //kernel
#define BULK_IN_EP 0x82
#define BULK_OUT_EP 0x02
#define INT_IN_EP 0x83
#endif



/* table of devices that work with this driver */
static struct usb_device_id skel_table [] = {
	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
	{ }					/* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, skel_table);


/* Get a minor range for your devices from the usb maintainer */
#define USB_SKEL_MINOR_BASE	192

/* our private defines. if this grows any larger, use your own .h file */
#define MAX_TRANSFER		(PAGE_SIZE - 512)
/* MAX_TRANSFER is chosen so that the VM is not stressed by
   allocations > PAGE_SIZE and the number of packets in a page
   is an integer 512 is the largest possible packet on EHCI */
#define WRITES_IN_FLIGHT	8
/* arbitrarily chosen */

/* Structure to hold all of our device specific stuff */
struct usb_skel {
	struct usb_device	*udev;			/* the usb device for this device */
	struct usb_interface	*interface;		/* the interface for this device */
	struct semaphore	limit_sem;		/* limiting the number of writes in progress */
	struct usb_anchor	submitted;		/* in case we need to retract our submissions */
	unsigned char           *bulk_in_buffer;	/* the buffer to receive data */
	unsigned char 		*int_in_buffer;
	size_t			bulk_in_size;		/* the size of the receive buffer */
	size_t			int_in_size;
	__u8			bulk_in_endpointAddr;	/* the address of the bulk in endpoint */
	__u8			bulk_out_endpointAddr;	/* the address of the bulk out endpoint */
	__u8			int_in_endpointAddr;	/* the address of the int in endpoint */
	int			errors;			/* the last request tanked */
	int			open_count;		/* count the number of openers */
	spinlock_t		err_lock;		/* lock for errors */
	struct kref		kref;
	struct mutex		io_mutex;		/* synchronize I/O with disconnect */
};
#define to_skel_dev(d) container_of(d, struct usb_skel, kref)

static struct usb_driver skel_driver;
static void skel_draw_down(struct usb_skel *dev);

static void skel_delete(struct kref *kref)
{
	struct usb_skel *dev = to_skel_dev(kref);

	usb_put_dev(dev->udev);
	kfree(dev->bulk_in_buffer);
	kfree(dev);
}

static int skel_open(struct inode *inode, struct file *file)
{
	info("skel_open ok.");
	
	struct usb_skel *dev;
	struct usb_interface *interface;
	int subminor;
	int retval = 0;

	subminor = iminor(inode);

	interface = usb_find_interface(&skel_driver, subminor);
	if (!interface) {
		printk("%s - error, can't find device for minor %d",
		     __func__, subminor);
		retval = -ENODEV;
		goto exit;
	}

	dev = usb_get_intfdata(interface);
	if (!dev) {
		retval = -ENODEV;
		goto exit;
	}

	/* increment our usage count for the device */
	kref_get(&dev->kref);

	/* lock the device to allow correctly handling errors
	 * in resumption */
	mutex_lock(&dev->io_mutex);

	if (!dev->open_count++) {
		retval = usb_autopm_get_interface(interface);
			if (retval) {
				dev->open_count--;
				mutex_unlock(&dev->io_mutex);
				kref_put(&dev->kref, skel_delete);
				goto exit;
			}
	} /* else { //uncomment this block if you want exclusive open
		retval = -EBUSY;
		dev->open_count--;
		mutex_unlock(&dev->io_mutex);
		kref_put(&dev->kref, skel_delete);
		goto exit;
	} */
	/* prevent the device from being autosuspended */

	/* save our object in the file's private structure */
	file->private_data = dev;
	mutex_unlock(&dev->io_mutex);

exit:
	return retval;
}

static int skel_release(struct inode *inode, struct file *file)
{
	struct usb_skel *dev;

	dev = (struct usb_skel *)file->private_data;
	if (dev == NULL)
		return -ENODEV;

	/* allow the device to be autosuspended */
	mutex_lock(&dev->io_mutex);
	if (!--dev->open_count && dev->interface)
		usb_autopm_put_interface(dev->interface);
	mutex_unlock(&dev->io_mutex);

	/* decrement the count on our device */
	kref_put(&dev->kref, skel_delete);
	printk(KERN_ALERT "I't no error\n");
	return 0;
}

static int skel_flush(struct file *file, fl_owner_t id)
{
	struct usb_skel *dev;
	int res;

	dev = (struct usb_skel *)file->private_data;
	if (dev == NULL)
		return -ENODEV;

	/* wait for io to stop */
	mutex_lock(&dev->io_mutex);
	skel_draw_down(dev);

	/* read out errors, leave subsequent opens a clean slate */
	spin_lock_irq(&dev->err_lock);
	res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
	dev->errors = 0;
	spin_unlock_irq(&dev->err_lock);

	mutex_unlock(&dev->io_mutex);

	return res;
}

static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
{
	info("skel_read ok.");
	
	struct usb_skel *dev;
	int retval;
	int bytes_read;

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

	mutex_lock(&dev->io_mutex);
	if (!dev->interface) {		/* disconnect() was called */
		retval = -ENODEV;
		goto exit;
	}

	/* do a blocking bulk read to get data from the device */
	retval = usb_bulk_msg(dev->udev,
			      usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
			      dev->bulk_in_buffer,
			      min(dev->bulk_in_size, count),
			      &bytes_read, 5000);

	/* if the read was successful, copy the data to userspace */
	if (!retval) {
		if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
			retval = -EFAULT;
		else
			retval = bytes_read;
	}

exit:
	mutex_unlock(&dev->io_mutex);
	if (retval < 0)
		retval = 0;
	return retval;
}

static void skel_write_bulk_callback(struct urb *urb)
{
	struct usb_skel *dev;

	dev = urb->context;

	/* sync/async unlink faults aren't errors */
	if (urb->status) {
		if(!(urb->status == -ENOENT ||
		    urb->status == -ECONNRESET ||
		    urb->status == -ESHUTDOWN))
			printk("%s - nonzero write bulk status received: %d",
			    __func__, urb->status);

		spin_lock(&dev->err_lock);
		dev->errors = urb->status;
		spin_unlock(&dev->err_lock);
	}

	/* free up our allocated buffer */
	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
			urb->transfer_buffer, urb->transfer_dma);
	up(&dev->limit_sem);
}

static ssize_t skel_write(struct file *file, const char *user_buffer, size_t count, loff_t *ppos)
{
	info("skel_write ok.");
	
	struct usb_skel *dev;
	int retval = 0;
	struct urb *urb = NULL;
	char *buf = NULL;
	size_t writesize = min(count, (size_t)MAX_TRANSFER);

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

	/* verify that we actually have some data to write */
	if (count == 0)
		goto exit;

	/* limit the number of URBs in flight to stop a user from using up all RAM */
	if (down_interruptible(&dev->limit_sem)) {
		retval = -ERESTARTSYS;
		goto exit;
	}

	spin_lock_irq(&dev->err_lock);
	if ((retval = dev->errors) < 0) {
		/* any error is reported once */
		dev->errors = 0;
		/* to preserve notifications about reset */
		retval = (retval == -EPIPE) ? retval : -EIO;
	}
	spin_unlock_irq(&dev->err_lock);
	if (retval < 0)
		goto error;

	/* create a urb, and a buffer for it, and copy the data to the urb */
	urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!urb) {
		retval = -ENOMEM;
		goto error;
	}

	buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
	if (!buf) {
		retval = -ENOMEM;
		goto error;
	}

	if (copy_from_user(buf, user_buffer, writesize)) {
		retval = -EFAULT;
		goto error;
	}

	/* this lock makes sure we don't submit URBs to gone devices */
	mutex_lock(&dev->io_mutex);
	if (!dev->interface) {		/* disconnect() was called */
		mutex_unlock(&dev->io_mutex);
		retval = -ENODEV;
		goto error;
	}

	/* initialize the urb properly */
	usb_fill_bulk_urb(urb, dev->udev,
			  usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
			  buf, writesize, skel_write_bulk_callback, dev);
	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
	usb_anchor_urb(urb, &dev->submitted);

	/* send the data out the bulk port */
	retval = usb_submit_urb(urb, GFP_KERNEL);
	mutex_unlock(&dev->io_mutex);
	if (retval) {
		printk("%s - failed submitting write urb, error %d", __func__, retval);
		goto error_unanchor;
	}

	/* release our reference to this urb, the USB core will eventually free it entirely */
	usb_free_urb(urb);


	return writesize;

error_unanchor:
	usb_unanchor_urb(urb);
error:
	if (urb) {
		usb_free_coherent(dev->udev, writesize, buf, urb->transfer_dma);
		usb_free_urb(urb);
	}
	up(&dev->limit_sem);

exit:
	return retval;
}

static const struct file_operations skel_fops = {
	.owner =	THIS_MODULE,
	.read =		skel_read,
	.write =	skel_write,
	.open =		skel_open,
	.release =	skel_release,
	.flush =	skel_flush,
};

/*
 * usb class driver info in order to get a minor number from the usb core,
 * and to have the device registered with the driver core
 */
static struct usb_class_driver skel_class = {
	.name =		"skel%d",	// /dev/skeln ,device name
	.fops =		&skel_fops,
	.minor_base =	USB_SKEL_MINOR_BASE,
};

static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
	struct usb_skel *dev;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	size_t buffer_size;
	int i;
	int retval = -ENOMEM;

	/* allocate memory for our device state and initialize it */
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev) {
		printk("Out of memory");
		goto error;
	}
	kref_init(&dev->kref);
	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
	mutex_init(&dev->io_mutex);
	spin_lock_init(&dev->err_lock);
	init_usb_anchor(&dev->submitted);

	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	dev->interface = interface;

	/* set up the endpoint information */
	/* use only the first bulk-in and bulk-out endpoints */
	iface_desc = interface->cur_altsetting;
	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
		endpoint = &iface_desc->endpoint[i].desc;

		printk(KERN_ALERT "find endpoint: 0x%x, size: %d\n", endpoint->bEndpointAddress, endpoint->wMaxPacketSize);

		if (!dev->bulk_in_endpointAddr &&
		    usb_endpoint_is_bulk_in(endpoint) && endpoint->bEndpointAddress == BULK_IN_EP) {
			/* we found a bulk in endpoint */
			buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
			dev->bulk_in_size = buffer_size;
			dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
			dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
			if (!dev->bulk_in_buffer) {
				printk("Could not allocate bulk_in_buffer");
				goto error;
			}
			info("Find bulk in addr: %d, size: %d\n", dev->bulk_in_endpointAddr, dev->bulk_in_size);
		}

		if (!dev->bulk_out_endpointAddr &&
		    usb_endpoint_is_bulk_out(endpoint) && endpoint->bEndpointAddress == BULK_OUT_EP) {
			/* we found a bulk out endpoint */
			dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
			info("Find bulk out addr: %d, size: %d\n", dev->bulk_out_endpointAddr, le16_to_cpu(endpoint->wMaxPacketSize));
		}

		if (!dev->int_in_endpointAddr &&
		    usb_endpoint_is_int_in(endpoint) && endpoint->bEndpointAddress == INT_IN_EP) {
			buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
			dev->int_in_size = buffer_size;
			dev->int_in_endpointAddr = endpoint->bEndpointAddress;
			dev->int_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
			if (!dev->int_in_buffer) {
				printk("Could not allocate int_in_buffer");
				goto error;
			}
			info("Find int in addr: %d, size: %d\n", dev->int_in_endpointAddr, dev->int_in_size);
		}
	}
	if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr && dev->int_in_endpointAddr)) {
		printk("Could not find both bulk-in and bulk-out endpoints");
		goto error;
	}

	/* save our data pointer in this interface device */
	usb_set_intfdata(interface, dev);

	/* we can register the device now, as it is ready */
	retval = usb_register_dev(interface, &skel_class);
	if (retval) {
		/* something prevented us from registering this driver */
		printk("Not able to get a minor for this device.");
		usb_set_intfdata(interface, NULL);
		goto error;
	}

	/* let the user know what node this device is now attached to */
	info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
	return 0;

error:
	if (dev)
		/* this frees allocated memory */
		kref_put(&dev->kref, skel_delete);
	return retval;
}

static void skel_disconnect(struct usb_interface *interface)
{
	struct usb_skel *dev;
	int minor = interface->minor;

	dev = usb_get_intfdata(interface);
	usb_set_intfdata(interface, NULL);

	/* give back our minor */
	usb_deregister_dev(interface, &skel_class);

	/* prevent more I/O from starting */
	mutex_lock(&dev->io_mutex);
	dev->interface = NULL;
	mutex_unlock(&dev->io_mutex);

	usb_kill_anchored_urbs(&dev->submitted);

	/* decrement our usage count */
	kref_put(&dev->kref, skel_delete);

	info("USB Skeleton #%d now disconnected", minor);
}

static void skel_draw_down(struct usb_skel *dev)
{
	int time;

	time = usb_wait_anchor_empty_timeout(&dev->submitted, 10000);
	if (!time)
		usb_kill_anchored_urbs(&dev->submitted);
}

static int skel_suspend(struct usb_interface *intf, pm_message_t message)
{
	struct usb_skel *dev = usb_get_intfdata(intf);

	if (!dev)
		return 0;
	skel_draw_down(dev);
	return 0;
}

static int skel_resume (struct usb_interface *intf)
{
	return 0;
}

static int skel_pre_reset(struct usb_interface *intf)
{
	struct usb_skel *dev = usb_get_intfdata(intf);

	mutex_lock(&dev->io_mutex);
	skel_draw_down(dev);

	return 0;
}

static int skel_post_reset(struct usb_interface *intf)
{
	struct usb_skel *dev = usb_get_intfdata(intf);

	/* we are sure no URBs are active - no locking needed */
	dev->errors = -EPIPE;
	mutex_unlock(&dev->io_mutex);

	return 0;
}

static struct usb_driver skel_driver = {
	.name =		"skeleton",
	.probe =	skel_probe,
	.disconnect =	skel_disconnect,
	.suspend =	skel_suspend,
	.resume =	skel_resume,
	.pre_reset =	skel_pre_reset,
	.post_reset =	skel_post_reset,
	.id_table =	skel_table,
	.supports_autosuspend = 1,
};

static int __init usb_skel_init(void)
{
	int result;

	/* register this driver with the USB subsystem */
	result = usb_register(&skel_driver);
	if (result)
		printk("usb_register failed. Error number %d", result);
	else
		printk("usb_register suss.");

	return result;
}

static void __exit usb_skel_exit(void)
{
	/* deregister this driver with the USB subsystem */
	usb_deregister(&skel_driver);
}

module_init(usb_skel_init);
module_exit(usb_skel_exit);

MODULE_LICENSE("GPL");

2. usb.c

#include <stdio.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/select.h>
#include <errno.h>
#include <pthread.h>


#define USB_NODE "/dev/skel0"


int fd;
int rev_size;
int send_size;

char *send_buf;
char *rev_buf;

void *bulk_rev(void *arg)
{

	int ret = 0;
	fd_set read_fd;	
	struct timeval tv;
	
	tv.tv_sec = 10;
	tv.tv_usec = 0;
	
	printf("rev thread created.\n");
	
    while(1)
    {
		FD_ZERO(&read_fd);
		FD_SET(fd, &read_fd);		
		ret = select(fd+1, &read_fd, NULL, NULL, NULL);		
		if (ret < 0) {
			perror("select");
			exit(1);
		}

		
		if (FD_ISSET(fd, &read_fd)) {
			ret = read(fd, (void*)rev_buf, rev_size);
			if (ret < 0) {
				perror("read");
				close(fd);
				exit(1);
			}
			
			*(rev_buf+ret) = '\0';
			
			printf("read %d bytes\n", ret);
			printf("rev data:%s \n\n", rev_buf);
			fflush(NULL);

		}
    }

	
}



int main(int argc, char **argv)
{
	printf("linux skeleton program test . ---by baoli \n\n");
	
	if (argc != 3) {
		fprintf(stderr, "Usage: %s [node] [read_total_size]\n", argv[0]);
		exit(1);
	}
	
	int ret = 0;
    pthread_t a_thread;	
	fd_set write_fd;
	
	rev_size  = atoi(argv[1]);	
	send_size = atoi(argv[2]);
	fd = open(USB_NODE, O_RDWR);	//open usb

	if (fd == -1) {
		printf("usb Open faild! errno:%d\n", errno);
		perror("open");
		exit(1);
	}
	printf("Open usb OK\n");
	
	send_buf = (char*)malloc(send_size+1);
	if (send_buf == NULL) {
		perror("malloc");
		exit(1);
	}	
	rev_buf = (char*)malloc(rev_size+1);
	if (rev_buf == NULL) {
		perror("malloc");
		exit(1);
	}

	memset((void*)send_buf, '2', send_size);
	
	//send data
	ret = write(fd, send_buf, send_size);
	if(ret <= 0)	
		printf("write err, ret: %d \n", ret);
	else
		printf("write sucss, ret: %d \n", ret);	
		
	
    //new thread,usb rev data
    ret = pthread_create(&a_thread, NULL, bulk_rev, NULL);
    if(ret !=0 )
    {
        perror("thread creation faild\n");
    }
	
	
	while(1){	
		printf("\n ---i am runing---\n");
		sleep(2);
	}
	
	free(send_buf);
	free(rev_buf);

	close(fd);
	return 0;
}