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So I have found this source code of a usb pen driver, I inserted the vendor id and product id of my device then I mad the make file I ...
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  1. #1
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    Post How to transfer data to a usb stick using a home coded driver


    So I have found this source code of a usb pen driver, I inserted the vendor id and product id of my device then I mad the make file I inserted the module (using insmod module.ko) after removing the usb-storage module (using rmmod usb-storage) but I don't know how to transfer data to my usb pen, any ideas?
    this is the source code:
    Code:
      #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/uaccess.h>
      #include <linux/usb.h>
      #include <linux/mutex.h> 
    
    /* Define these values to match your devices */
        #define USB_SKEL_VENDOR_ID       0x14cd 
        #define USB_SKEL_PRODUCT_ID      0x125c
        
        /* table of devices that work with this driver */
        static const 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     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 */
                struct urb              *bulk_in_urb;           /* the urb to read data with */
                unsigned char           *bulk_in_buffer;        /* the buffer to receive data */
                size_t                  bulk_in_size;           /* the size of the receive buffer */
                size_t                  bulk_in_filled;         /* number of bytes in the buffer */
                size_t                  bulk_in_copied;         /* already copied to user space */
                __u8                     bulk_in_endpointAddr;   /* the address of the bulk in endpoint */
                __u8                     bulk_out_endpointAddr;  /* the address of the bulk out endpoint */
                int                     errors;                 /* the last request tanked */
                bool                    ongoing_read;           /* a read is going on */
                spinlock_t              err_lock;               /* lock for errors */
                struct kref             kref;
                struct mutex            io_mutex;               /* synchronize I/O with disconnect */
                wait_queue_head_t       bulk_in_wait;           /* to wait for an ongoing read */
        };
        #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_free_urb(dev->bulk_in_urb);
                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) {
                        pr_err("%s - error, can't find device for minor %d\n",__func__, subminor);
                        retval = -ENODEV;
                        goto exit;
                }
        
                dev = usb_get_intfdata(interface);
                if (!dev) {
                        retval = -ENODEV;
                        goto exit;
                }
        
                retval = usb_autopm_get_interface(interface);
                if (retval)
                        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 = file->private_data;
                if (dev == NULL)
                        return -ENODEV;
        
                /* allow the device to be autosuspended */
                mutex_lock(&dev->io_mutex);
                if (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);
                return 0;
        }
        
        static int skel_flush(struct file *file, fl_owner_t id)
        {
                struct usb_skel *dev;
                int res;
        
                dev = 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 void skel_read_bulk_callback(struct urb *urb)
        {
                struct usb_skel *dev;
        
                dev = urb->context;
        
                spin_lock(&dev->err_lock);
                /* sync/async unlink faults aren't errors */
                if (urb->status) {
                        if (!(urb->status == -ENOENT ||
                            urb->status == -ECONNRESET ||
                            urb->status == -ESHUTDOWN))
                                dev_err(&dev->interface->dev,
                                        "%s - nonzero write bulk status received: %d\n",
                                        __func__, urb->status);
        
                        dev->errors = urb->status;
                } else {
                        dev->bulk_in_filled = urb->actual_length;
                }
                dev->ongoing_read = 0;
                spin_unlock(&dev->err_lock);
        
                wake_up_interruptible(&dev->bulk_in_wait);
        }
        
        static int skel_do_read_io(struct usb_skel *dev, size_t count)
        {
                int rv;
        
                /* prepare a read */
                usb_fill_bulk_urb(dev->bulk_in_urb,
                                dev->udev,
                                usb_rcvbulkpipe(dev->udev,
                                        dev->bulk_in_endpointAddr),
                                dev->bulk_in_buffer,
                                min(dev->bulk_in_size, count),
                                skel_read_bulk_callback,
                                dev);
                /* tell everybody to leave the URB alone */
                spin_lock_irq(&dev->err_lock);
                dev->ongoing_read = 0;
                spin_unlock_irq(&dev->err_lock);
        
                /* submit bulk in urb, which means no data to deliver */
                dev->bulk_in_filled =  0;
                dev->bulk_in_copied =  0;
        
                /* do it */
                rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL);
                if (rv < 0) {
                        dev_err(&dev->interface->dev,
                                "%s - failed submitting read urb, error %d\n",
                                __func__, rv);
                        rv = (rv == -ENOMEM) ? rv : -EIO;
                        spin_lock_irq(&dev->err_lock);
                        dev->ongoing_read = 0;
                        spin_unlock_irq(&dev->err_lock);
                }
        
                return rv;
        }
        
        static ssize_t skel_read(struct file *file, char *buffer, size_t count,
                                 loff_t *ppos)
        {
                struct usb_skel *dev;
                int rv;
                bool ongoing_io;
        
                dev = file->private_data;
        
                /* if we cannot read at all, return EOF */
                if (!dev->bulk_in_urb || !count)
                        return 0 ;
        
                /* no concurrent readers */
                rv = mutex_lock_interruptible(&dev->io_mutex);
                if (rv < 0 )
                        return rv;
        
                if (!dev->interface) {          /* disconnect() was called */
                        rv = -ENODEV;
                        goto exit;
                }
        
                /* if IO is under way, we must not touch things */
        retry:
                spin_lock_irq(&dev->err_lock);
                ongoing_io = dev->ongoing_read;
                spin_unlock_irq(&dev->err_lock);
        
                if (ongoing_io) {
                        /* nonblocking IO shall not wait */
                        if (file->f_flags & O_NONBLOCK) {
                                rv = -EAGAIN;
                                goto exit;
                        }
                        /*
                         * IO may take forever
                         * hence wait in an interruptible state
                         */
                        rv = wait_event_interruptible(dev->bulk_in_wait, (!dev->ongoing_read));
                        if (rv < 0)
                                goto exit;
                }
        
                /* errors must be reported */
                rv = dev->errors;
                if (rv < 0 ) {
                        /* any error is reported once */
                        dev->errors = 0;
                        /* to preserve notifications about reset */
                        rv = (rv == -EPIPE) ? rv : -EIO;
                        /* report it */
                        goto exit;
                }
        
                /*
                 * if the buffer is filled we may satisfy the read
                 * else we need to start IO
                 */
        
                if (dev->bulk_in_filled) {
                        /* we had read data */
                        size_t available = dev->bulk_in_filled - dev->bulk_in_copied;
                        size_t chunk = min(available, count);
        
                        if (!available) {
                                /*
                                 * all data has been used
                                 * actual IO needs to be done
                                 */
                                rv = skel_do_read_io(dev, count);
                                if (rv < 0 )
                                        goto exit;
                                else
                                        goto retry;
                        }
                        /*
                         * data is available
                         * chunk tells us how much shall be copied
                         */
        
                        if (copy_to_user(buffer,
                                         dev->bulk_in_buffer + dev->bulk_in_copied,
                                         chunk))
                                rv = -EFAULT;
                        else
                                rv = chunk;
        
                        dev->bulk_in_copied += chunk;
        
                        /*
                         * if we are asked for more than we have,
                         * we start IO but don't wait
                         */
                        if (available < count)
                                skel_do_read_io(dev, count - chunk);
                } else {
                        /* no data in the buffer */
                        rv = skel_do_read_io(dev, count);
                        if (rv < 0)
                                goto exit;
                        else if (!(file->f_flags & O_NONBLOCK))
                                goto retry;
                        rv = -EAGAIN;
                }
        exit:
                mutex_unlock(&dev->io_mutex);
                return rv;
        }
        
        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))
                                dev_err(&dev->interface->dev,
                                        "%s - nonzero write bulk status received: %d\n",
                                        __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)
        {
                struct usb_skel *dev;
                int retval = 0;
                struct urb *urb = NULL;
                char *buf = NULL;
                size_t writesize = min(count, (size_t)MAX_TRANSFER);
        
                dev = 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 (!(file->f_flags & O_NONBLOCK)) {
                        if (down_interruptible(&dev->limit_sem)) {
                                retval = -ERESTARTSYS;
                                goto exit;
                        }
                } else {
                        if (down_trylock(&dev->limit_sem)) {
                                retval = -EAGAIN;
                                goto exit;
                        }
                }
        
                spin_lock_irq(&dev->err_lock);
                retval = dev->errors;
                if (retval < 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) {
                        dev_err(&dev->interface->dev,
                                "%s - failed submitting write urb, error %d\n",
                                __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,
                .llseek =       noop_llseek,
        };
        
        /*
         * 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",
                .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) {
                        dev_err(&interface->dev, "Out of memory\n");
                        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);
                init_waitqueue_head(&dev->bulk_in_wait);
        
                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 &&
                            usb_endpoint_is_bulk_in(endpoint)) {
                                /* we found a bulk in endpoint */
                                buffer_size = usb_endpoint_maxp(endpoint);
                                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) {
                                        dev_err(&interface->dev,
                                                "Could not allocate bulk_in_buffer\n");
                                        goto error;
                                }
                                dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL);
                                if (!dev->bulk_in_urb) {
                                        dev_err(&interface->dev,
                                                "Could not allocate bulk_in_urb\n");
                                        goto error;
                                }
                        }
        
                        if (!dev->bulk_out_endpointAddr &&
                            usb_endpoint_is_bulk_out(endpoint)) {
                                /* we found a bulk out endpoint */
                                dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
                        }
                }
                if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
                        dev_err(&interface->dev,
                                "Could not find both bulk-in and bulk-out endpoints\n");
                        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 */
                        dev_err(&interface->dev,
                                "Not able to get a minor for this device.\n");
                        usb_set_intfdata(interface, NULL);
                        goto error;
                }
        
                /* let the user know what node this device is now attached to */
                dev_info(&interface->dev,
                         "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);
        
                dev_info(&interface->dev, "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,1000);
                if (!time)
                        usb_kill_anchored_urbs(&dev->submitted);
                usb_kill_urb(dev->bulk_in_urb);
        }
        
        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 =         "kingston",
                .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,
        };
        
        module_usb_driver(skel_driver);
        
        MODULE_LICENSE("GPL");
    Last edited by atreyu; 10-10-2013 at 04:13 AM. Reason: added CODE tags to aid in readability

  2. #2
    Trusted Penguin
    Join Date
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    4,353
    hello and welcome, takisho!

    does your USB pen drive not already work under Linux? or are you trying to intentionally access it using your own driver? in any case, i think you'd still need the usb storage module, unless the driver code you posted (i did not look at it) replaces all of its functionality (which I doubt). Something has to create and manage a virtual block device (like /dev/sdb) which the kernel uses to read to and write from the drive.

  3. #3
    Just Joined!
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    oops I think I made a mistake, I think this code is for a char device and usb pen is a block device, but anyway can you please tell me how to adapte this code to manipulate a char device such as a mouse or any other device that you propose, my main goal is to experience the practical part of device drivers programming and not staying only in the theoretical part.
    Thank you in advance atreyu

  4. $spacer_open
    $spacer_close
  5. #4
    Trusted Penguin
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    Quote Originally Posted by takisho View Post
    but anyway can you please tell me how to adapte this code to manipulate a char device such as a mouse or any other device that you propose
    sry, that's a bit too broad for a forum discussion (and besides that, I wouldn't be of much help to you anyway). i'd recommend picking up a good book on writing Linux Kernel drivers.

  6. #5
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    ok thanks alot for your help atreyu.

  7. #6
    Trusted Penguin
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    np. do come back around when you've got a specific question, though!

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