usb-skeleton.c

/** USB Skeleton driver - 2.0** 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 easy to read and use, as no locks are now* needed anymore.**/#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/kref.h>
#include <linux/smp_lock.h>
#include <linux/usb.h>
#include <asm/uaccess.h>/* Define these values to match your devices */
#define USB_SKEL_VENDOR_ID  0xfff0
#define USB_SKEL_PRODUCT_ID 0xfff0/* 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/* 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 */unsigned char *      bulk_in_buffer;     /* the buffer to receive data */size_t          bulk_in_size;       /* the size of the receive buffer */__u8            bulk_in_endpointAddr;   /* the address of the bulk in endpoint */__u8           bulk_out_endpointAddr;  /* the address of the bulk out endpoint */struct kref       kref;
};
#define to_skel_dev(d) container_of(d, struct usb_skel, kref)static struct usb_driver skel_driver;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)
{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) {err ("%s - error, can't find device for minor %d",__FUNCTION__, 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);/* save our object in the file's private structure */file->private_data = dev;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;/* decrement the count on our device */kref_put(&dev->kref, skel_delete);return 0;
}static ssize_t skel_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{struct usb_skel *dev;int retval = 0;dev = (struct usb_skel *)file->private_data;/* 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),&count, HZ*10);/* if the read was successful, copy the data to userspace */if (!retval) {if (copy_to_user(buffer, dev->bulk_in_buffer, count))retval = -EFAULT;elseretval = count;}return retval;
}static void skel_write_bulk_callback(struct urb *urb, struct pt_regs *regs)
{/* sync/async unlink faults aren't errors */if (urb->status && !(urb->status == -ENOENT || urb->status == -ECONNRESET ||urb->status == -ESHUTDOWN)) {dbg("%s - nonzero write bulk status received: %d",__FUNCTION__, urb->status);}/* free up our allocated buffer */usb_buffer_free(urb->dev, urb->transfer_buffer_length, urb->transfer_buffer, urb->transfer_dma);
}static ssize_t skel_write(struct file *file, const char __user *user_buffer, size_t count, loff_t *ppos)
{struct usb_skel *dev;int retval = 0;struct urb *urb = NULL;char *buf = NULL;dev = (struct usb_skel *)file->private_data;/* verify that we actually have some data to write */if (count == 0)goto exit;/* 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_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);if (!buf) {retval = -ENOMEM;goto error;}if (copy_from_user(buf, user_buffer, count)) {retval = -EFAULT;goto error;}/* initialize the urb properly */usb_fill_bulk_urb(urb, dev->udev,usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),buf, count, skel_write_bulk_callback, dev);urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;/* send the data out the bulk port */retval = usb_submit_urb(urb, GFP_KERNEL);if (retval) {err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);goto error;}/* release our reference to this urb, the USB core will eventually free it entirely */usb_free_urb(urb);exit:return count;error:usb_buffer_free(dev->udev, count, buf, urb->transfer_dma);usb_free_urb(urb);kfree(buf);return retval;
}static struct file_operations skel_fops = {.owner =  THIS_MODULE,.read =        skel_read,.write = skel_write,.open =     skel_open,.release =   skel_release,
};/* * 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 skel_class = {.name = "usb/skel%d",.fops = &skel_fops,.mode = S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH,.minor_base = USB_SKEL_MINOR_BASE,
};static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
{struct usb_skel *dev = NULL;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 = kmalloc(sizeof(struct usb_skel), GFP_KERNEL);if (dev == NULL) {err("Out of memory");goto error;}memset(dev, 0x00, sizeof (*dev));kref_init(&dev->kref);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;if (!dev->bulk_in_endpointAddr &&(endpoint->bEndpointAddress & USB_DIR_IN) &&((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)== USB_ENDPOINT_XFER_BULK)) {/* we found a bulk in endpoint */buffer_size = 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) {err("Could not allocate bulk_in_buffer");goto error;}}if (!dev->bulk_out_endpointAddr &&!(endpoint->bEndpointAddress & USB_DIR_IN) &&((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)== USB_ENDPOINT_XFER_BULK)) {/* we found a bulk out endpoint */dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;}}if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {err("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 */err("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)kref_put(&dev->kref, skel_delete);return retval;
}static void skel_disconnect(struct usb_interface *interface)
{struct usb_skel *dev;int minor = interface->minor;/* prevent skel_open() from racing skel_disconnect() */lock_kernel();dev = usb_get_intfdata(interface);usb_set_intfdata(interface, NULL);/* give back our minor */usb_deregister_dev(interface, &skel_class);unlock_kernel();/* decrement our usage count */kref_put(&dev->kref, skel_delete);info("USB Skeleton #%d now disconnected", minor);
}static struct usb_driver skel_driver = {.owner = THIS_MODULE,.name = "skeleton",.id_table = skel_table,.probe = skel_probe,.disconnect = skel_disconnect,
};static int __init usb_skel_init(void)
{int result;/* register this driver with the USB subsystem */result = usb_register(&skel_driver);if (result)err("usb_register failed. Error number %d", result);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");

makefile

obj-m    := usb-skeleton.oKERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD       := $(shell pwd)all:$(MAKE) -C $(KERNELDIR) M=$(PWD)clean:rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions

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一个Linux USB驱动：USB Skeleton driver - 2.0

usb-skeleton.c

makefile

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