2017-11-03 04:28:30 -06:00
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// SPDX-License-Identifier: GPL-2.0
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2005-04-16 16:20:36 -06:00
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/*
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2006-08-14 19:44:29 -06:00
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* USB Skeleton driver - 2.2
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2005-04-16 16:20:36 -06:00
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*
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* Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
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*
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2006-08-14 19:44:29 -06:00
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* This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
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2006-07-01 20:06:36 -06:00
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* but has been rewritten to be easier to read and use.
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2005-04-16 16:20:36 -06:00
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/kref.h>
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2009-09-11 17:07:30 -06:00
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#include <linux/uaccess.h>
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2005-04-16 16:20:36 -06:00
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#include <linux/usb.h>
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2006-07-01 20:06:36 -06:00
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#include <linux/mutex.h>
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2005-04-16 16:20:36 -06:00
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/* Define these values to match your devices */
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#define USB_SKEL_VENDOR_ID 0xfff0
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#define USB_SKEL_PRODUCT_ID 0xfff0
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/* table of devices that work with this driver */
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2010-01-10 07:33:33 -07:00
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static const struct usb_device_id skel_table[] = {
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2005-04-16 16:20:36 -06:00
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{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
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{ } /* Terminating entry */
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};
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2006-08-14 19:44:29 -06:00
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MODULE_DEVICE_TABLE(usb, skel_table);
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2005-04-16 16:20:36 -06:00
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/* Get a minor range for your devices from the usb maintainer */
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#define USB_SKEL_MINOR_BASE 192
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2005-12-21 11:27:29 -07:00
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/* our private defines. if this grows any larger, use your own .h file */
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2006-08-14 19:44:29 -06:00
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#define MAX_TRANSFER (PAGE_SIZE - 512)
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2007-03-01 06:31:02 -07:00
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/* MAX_TRANSFER is chosen so that the VM is not stressed by
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allocations > PAGE_SIZE and the number of packets in a page
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is an integer 512 is the largest possible packet on EHCI */
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2005-12-21 11:27:29 -07:00
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#define WRITES_IN_FLIGHT 8
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2007-03-01 06:31:02 -07:00
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/* arbitrarily chosen */
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2005-12-21 11:27:29 -07:00
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2005-04-16 16:20:36 -06:00
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/* Structure to hold all of our device specific stuff */
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struct usb_skel {
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2007-03-01 06:31:02 -07:00
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struct usb_device *udev; /* the usb device for this device */
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struct usb_interface *interface; /* the interface for this device */
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2005-12-21 11:27:29 -07:00
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struct semaphore limit_sem; /* limiting the number of writes in progress */
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2007-05-25 05:42:56 -06:00
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struct usb_anchor submitted; /* in case we need to retract our submissions */
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2009-09-09 09:06:53 -06:00
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struct urb *bulk_in_urb; /* the urb to read data with */
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2006-08-14 19:44:29 -06:00
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unsigned char *bulk_in_buffer; /* the buffer to receive data */
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2005-04-16 16:20:36 -06:00
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size_t bulk_in_size; /* the size of the receive buffer */
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2009-09-09 09:06:53 -06:00
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size_t bulk_in_filled; /* number of bytes in the buffer */
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size_t bulk_in_copied; /* already copied to user space */
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2005-04-16 16:20:36 -06:00
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__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
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__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
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2007-05-25 05:42:56 -06:00
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int errors; /* the last request tanked */
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2009-09-09 09:06:53 -06:00
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bool ongoing_read; /* a read is going on */
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2007-05-25 05:42:56 -06:00
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spinlock_t err_lock; /* lock for errors */
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2005-04-16 16:20:36 -06:00
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struct kref kref;
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2006-07-01 20:06:36 -06:00
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struct mutex io_mutex; /* synchronize I/O with disconnect */
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2013-03-20 06:47:46 -06:00
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wait_queue_head_t bulk_in_wait; /* to wait for an ongoing read */
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2005-04-16 16:20:36 -06:00
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};
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#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
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static struct usb_driver skel_driver;
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2007-05-25 05:42:56 -06:00
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static void skel_draw_down(struct usb_skel *dev);
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2005-04-16 16:20:36 -06:00
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static void skel_delete(struct kref *kref)
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2006-08-14 19:44:29 -06:00
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{
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2005-04-16 16:20:36 -06:00
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struct usb_skel *dev = to_skel_dev(kref);
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2009-09-09 09:06:53 -06:00
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usb_free_urb(dev->bulk_in_urb);
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2005-04-16 16:20:36 -06:00
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usb_put_dev(dev->udev);
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2006-08-14 19:44:29 -06:00
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kfree(dev->bulk_in_buffer);
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kfree(dev);
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2005-04-16 16:20:36 -06:00
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}
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static int skel_open(struct inode *inode, struct file *file)
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{
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struct usb_skel *dev;
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struct usb_interface *interface;
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int subminor;
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int retval = 0;
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subminor = iminor(inode);
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interface = usb_find_interface(&skel_driver, subminor);
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if (!interface) {
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2012-04-27 12:24:45 -06:00
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pr_err("%s - error, can't find device for minor %d\n",
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__func__, subminor);
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2005-04-16 16:20:36 -06:00
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retval = -ENODEV;
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goto exit;
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}
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dev = usb_get_intfdata(interface);
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if (!dev) {
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retval = -ENODEV;
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goto exit;
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}
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2011-12-16 07:20:44 -07:00
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retval = usb_autopm_get_interface(interface);
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if (retval)
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2012-10-10 08:14:00 -06:00
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goto exit;
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/* increment our usage count for the device */
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kref_get(&dev->kref);
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2005-04-16 16:20:36 -06:00
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/* save our object in the file's private structure */
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file->private_data = dev;
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exit:
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return retval;
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}
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static int skel_release(struct inode *inode, struct file *file)
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{
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struct usb_skel *dev;
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2010-07-12 14:50:13 -06:00
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dev = file->private_data;
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2005-04-16 16:20:36 -06:00
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if (dev == NULL)
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return -ENODEV;
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2006-08-30 13:47:18 -06:00
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/* allow the device to be autosuspended */
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mutex_lock(&dev->io_mutex);
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2011-12-16 07:20:44 -07:00
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if (dev->interface)
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2006-08-30 13:47:18 -06:00
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usb_autopm_put_interface(dev->interface);
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mutex_unlock(&dev->io_mutex);
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2005-04-16 16:20:36 -06:00
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/* decrement the count on our device */
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kref_put(&dev->kref, skel_delete);
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return 0;
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}
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2007-05-25 05:42:56 -06:00
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static int skel_flush(struct file *file, fl_owner_t id)
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{
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struct usb_skel *dev;
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int res;
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2010-07-12 14:50:13 -06:00
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dev = file->private_data;
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2007-05-25 05:42:56 -06:00
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if (dev == NULL)
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return -ENODEV;
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/* wait for io to stop */
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mutex_lock(&dev->io_mutex);
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skel_draw_down(dev);
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/* read out errors, leave subsequent opens a clean slate */
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spin_lock_irq(&dev->err_lock);
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res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
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dev->errors = 0;
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spin_unlock_irq(&dev->err_lock);
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mutex_unlock(&dev->io_mutex);
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return res;
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}
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2009-09-09 09:06:53 -06:00
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static void skel_read_bulk_callback(struct urb *urb)
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{
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struct usb_skel *dev;
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dev = urb->context;
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spin_lock(&dev->err_lock);
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/* sync/async unlink faults aren't errors */
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if (urb->status) {
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2009-09-11 17:07:30 -06:00
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if (!(urb->status == -ENOENT ||
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2009-09-09 09:06:53 -06:00
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urb->status == -ECONNRESET ||
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urb->status == -ESHUTDOWN))
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2012-04-27 12:24:45 -06:00
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dev_err(&dev->interface->dev,
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"%s - nonzero write bulk status received: %d\n",
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__func__, urb->status);
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2009-09-09 09:06:53 -06:00
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dev->errors = urb->status;
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} else {
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dev->bulk_in_filled = urb->actual_length;
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}
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dev->ongoing_read = 0;
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spin_unlock(&dev->err_lock);
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2013-03-20 06:47:46 -06:00
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wake_up_interruptible(&dev->bulk_in_wait);
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2009-09-09 09:06:53 -06:00
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}
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static int skel_do_read_io(struct usb_skel *dev, size_t count)
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{
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int rv;
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/* prepare a read */
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usb_fill_bulk_urb(dev->bulk_in_urb,
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dev->udev,
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usb_rcvbulkpipe(dev->udev,
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dev->bulk_in_endpointAddr),
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dev->bulk_in_buffer,
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min(dev->bulk_in_size, count),
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skel_read_bulk_callback,
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dev);
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/* tell everybody to leave the URB alone */
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spin_lock_irq(&dev->err_lock);
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dev->ongoing_read = 1;
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spin_unlock_irq(&dev->err_lock);
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2013-03-20 06:47:46 -06:00
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/* submit bulk in urb, which means no data to deliver */
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dev->bulk_in_filled = 0;
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dev->bulk_in_copied = 0;
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2009-09-09 09:06:53 -06:00
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/* do it */
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rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL);
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if (rv < 0) {
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2012-04-27 12:24:45 -06:00
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dev_err(&dev->interface->dev,
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"%s - failed submitting read urb, error %d\n",
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2009-09-09 09:06:53 -06:00
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__func__, rv);
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rv = (rv == -ENOMEM) ? rv : -EIO;
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spin_lock_irq(&dev->err_lock);
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dev->ongoing_read = 0;
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spin_unlock_irq(&dev->err_lock);
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}
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return rv;
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}
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2009-09-11 17:07:30 -06:00
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static ssize_t skel_read(struct file *file, char *buffer, size_t count,
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loff_t *ppos)
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2005-04-16 16:20:36 -06:00
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{
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struct usb_skel *dev;
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2009-09-09 09:06:53 -06:00
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int rv;
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bool ongoing_io;
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2005-04-16 16:20:36 -06:00
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2010-07-12 14:50:13 -06:00
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dev = file->private_data;
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2006-07-01 20:06:36 -06:00
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2009-09-09 09:06:53 -06:00
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/* if we cannot read at all, return EOF */
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if (!dev->bulk_in_urb || !count)
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return 0;
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/* no concurrent readers */
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rv = mutex_lock_interruptible(&dev->io_mutex);
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if (rv < 0)
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return rv;
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2006-07-01 20:06:36 -06:00
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if (!dev->interface) { /* disconnect() was called */
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2009-09-09 09:06:53 -06:00
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rv = -ENODEV;
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2006-07-01 20:06:36 -06:00
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goto exit;
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}
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2009-09-09 09:06:53 -06:00
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/* if IO is under way, we must not touch things */
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retry:
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spin_lock_irq(&dev->err_lock);
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ongoing_io = dev->ongoing_read;
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spin_unlock_irq(&dev->err_lock);
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if (ongoing_io) {
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2009-09-09 09:08:50 -06:00
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/* nonblocking IO shall not wait */
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if (file->f_flags & O_NONBLOCK) {
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rv = -EAGAIN;
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goto exit;
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}
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2009-09-09 09:06:53 -06:00
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/*
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* IO may take forever
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* hence wait in an interruptible state
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*/
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2013-03-20 06:47:46 -06:00
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rv = wait_event_interruptible(dev->bulk_in_wait, (!dev->ongoing_read));
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2009-09-09 09:06:53 -06:00
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if (rv < 0)
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goto exit;
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2005-04-16 16:20:36 -06:00
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}
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2009-09-09 09:06:53 -06:00
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/* errors must be reported */
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2009-09-11 17:07:30 -06:00
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rv = dev->errors;
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if (rv < 0) {
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2009-09-09 09:06:53 -06:00
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/* any error is reported once */
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dev->errors = 0;
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/* to preserve notifications about reset */
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rv = (rv == -EPIPE) ? rv : -EIO;
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/* report it */
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goto exit;
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}
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/*
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* if the buffer is filled we may satisfy the read
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* else we need to start IO
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*/
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if (dev->bulk_in_filled) {
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/* we had read data */
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size_t available = dev->bulk_in_filled - dev->bulk_in_copied;
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size_t chunk = min(available, count);
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if (!available) {
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/*
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* all data has been used
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* actual IO needs to be done
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*/
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rv = skel_do_read_io(dev, count);
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if (rv < 0)
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goto exit;
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else
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goto retry;
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}
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/*
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* data is available
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* chunk tells us how much shall be copied
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*/
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if (copy_to_user(buffer,
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dev->bulk_in_buffer + dev->bulk_in_copied,
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chunk))
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rv = -EFAULT;
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else
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rv = chunk;
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dev->bulk_in_copied += chunk;
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/*
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* if we are asked for more than we have,
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* we start IO but don't wait
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*/
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if (available < count)
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skel_do_read_io(dev, count - chunk);
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} else {
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/* no data in the buffer */
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|
rv = skel_do_read_io(dev, count);
|
|
|
|
if (rv < 0)
|
|
|
|
goto exit;
|
2013-07-18 20:15:18 -06:00
|
|
|
else
|
2009-09-09 09:06:53 -06:00
|
|
|
goto retry;
|
|
|
|
}
|
2006-07-01 20:06:36 -06:00
|
|
|
exit:
|
|
|
|
mutex_unlock(&dev->io_mutex);
|
2009-09-09 09:06:53 -06:00
|
|
|
return rv;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 07:55:46 -06:00
|
|
|
static void skel_write_bulk_callback(struct urb *urb)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
struct usb_skel *dev;
|
|
|
|
|
2008-02-24 03:41:47 -07:00
|
|
|
dev = urb->context;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
/* sync/async unlink faults aren't errors */
|
2007-05-25 05:42:56 -06:00
|
|
|
if (urb->status) {
|
2009-09-11 17:07:30 -06:00
|
|
|
if (!(urb->status == -ENOENT ||
|
2007-05-25 05:42:56 -06:00
|
|
|
urb->status == -ECONNRESET ||
|
|
|
|
urb->status == -ESHUTDOWN))
|
2012-04-27 12:24:45 -06:00
|
|
|
dev_err(&dev->interface->dev,
|
|
|
|
"%s - nonzero write bulk status received: %d\n",
|
|
|
|
__func__, urb->status);
|
2007-05-25 05:42:56 -06:00
|
|
|
|
|
|
|
spin_lock(&dev->err_lock);
|
|
|
|
dev->errors = urb->status;
|
|
|
|
spin_unlock(&dev->err_lock);
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
/* free up our allocated buffer */
|
2010-04-12 05:17:25 -06:00
|
|
|
usb_free_coherent(urb->dev, urb->transfer_buffer_length,
|
|
|
|
urb->transfer_buffer, urb->transfer_dma);
|
2005-12-21 11:27:29 -07:00
|
|
|
up(&dev->limit_sem);
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
2009-09-11 17:07:30 -06:00
|
|
|
static ssize_t skel_write(struct file *file, const char *user_buffer,
|
|
|
|
size_t count, loff_t *ppos)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
struct usb_skel *dev;
|
|
|
|
int retval = 0;
|
|
|
|
struct urb *urb = NULL;
|
|
|
|
char *buf = NULL;
|
2005-12-22 17:11:02 -07:00
|
|
|
size_t writesize = min(count, (size_t)MAX_TRANSFER);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2010-07-12 14:50:13 -06:00
|
|
|
dev = file->private_data;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
/* verify that we actually have some data to write */
|
|
|
|
if (count == 0)
|
|
|
|
goto exit;
|
|
|
|
|
2009-09-11 17:07:30 -06:00
|
|
|
/*
|
|
|
|
* limit the number of URBs in flight to stop a user from using up all
|
|
|
|
* RAM
|
|
|
|
*/
|
2009-09-19 01:13:43 -06:00
|
|
|
if (!(file->f_flags & O_NONBLOCK)) {
|
2009-09-09 02:23:35 -06:00
|
|
|
if (down_interruptible(&dev->limit_sem)) {
|
|
|
|
retval = -ERESTARTSYS;
|
|
|
|
goto exit;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
if (down_trylock(&dev->limit_sem)) {
|
|
|
|
retval = -EAGAIN;
|
|
|
|
goto exit;
|
|
|
|
}
|
2005-12-22 17:11:02 -07:00
|
|
|
}
|
2005-12-21 11:27:29 -07:00
|
|
|
|
2007-05-25 05:42:56 -06:00
|
|
|
spin_lock_irq(&dev->err_lock);
|
2009-09-11 17:07:30 -06:00
|
|
|
retval = dev->errors;
|
|
|
|
if (retval < 0) {
|
2007-05-25 05:42:56 -06:00
|
|
|
/* 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;
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
/* 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;
|
|
|
|
}
|
|
|
|
|
2010-04-12 05:17:25 -06:00
|
|
|
buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL,
|
|
|
|
&urb->transfer_dma);
|
2005-04-16 16:20:36 -06:00
|
|
|
if (!buf) {
|
|
|
|
retval = -ENOMEM;
|
|
|
|
goto error;
|
|
|
|
}
|
|
|
|
|
2005-12-21 11:27:29 -07:00
|
|
|
if (copy_from_user(buf, user_buffer, writesize)) {
|
2005-04-16 16:20:36 -06:00
|
|
|
retval = -EFAULT;
|
|
|
|
goto error;
|
|
|
|
}
|
|
|
|
|
2007-03-01 06:31:02 -07:00
|
|
|
/* 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;
|
|
|
|
}
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
/* initialize the urb properly */
|
|
|
|
usb_fill_bulk_urb(urb, dev->udev,
|
|
|
|
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
|
2005-12-21 11:27:29 -07:00
|
|
|
buf, writesize, skel_write_bulk_callback, dev);
|
2005-04-16 16:20:36 -06:00
|
|
|
urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
|
2007-05-25 05:42:56 -06:00
|
|
|
usb_anchor_urb(urb, &dev->submitted);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
/* send the data out the bulk port */
|
|
|
|
retval = usb_submit_urb(urb, GFP_KERNEL);
|
2007-03-01 06:31:02 -07:00
|
|
|
mutex_unlock(&dev->io_mutex);
|
2005-04-16 16:20:36 -06:00
|
|
|
if (retval) {
|
2012-04-27 12:24:45 -06:00
|
|
|
dev_err(&dev->interface->dev,
|
|
|
|
"%s - failed submitting write urb, error %d\n",
|
|
|
|
__func__, retval);
|
2007-05-25 05:42:56 -06:00
|
|
|
goto error_unanchor;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
2009-09-11 17:07:30 -06:00
|
|
|
/*
|
|
|
|
* release our reference to this urb, the USB core will eventually free
|
|
|
|
* it entirely
|
|
|
|
*/
|
2005-04-16 16:20:36 -06:00
|
|
|
usb_free_urb(urb);
|
|
|
|
|
2007-03-01 06:31:02 -07:00
|
|
|
|
2005-12-21 11:27:29 -07:00
|
|
|
return writesize;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2007-05-25 05:42:56 -06:00
|
|
|
error_unanchor:
|
|
|
|
usb_unanchor_urb(urb);
|
2005-04-16 16:20:36 -06:00
|
|
|
error:
|
2006-07-01 20:06:36 -06:00
|
|
|
if (urb) {
|
2010-04-12 05:17:25 -06:00
|
|
|
usb_free_coherent(dev->udev, writesize, buf, urb->transfer_dma);
|
2006-07-01 20:06:36 -06:00
|
|
|
usb_free_urb(urb);
|
|
|
|
}
|
2005-12-21 11:27:29 -07:00
|
|
|
up(&dev->limit_sem);
|
2006-07-01 20:06:36 -06:00
|
|
|
|
|
|
|
exit:
|
2005-04-16 16:20:36 -06:00
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
|
2006-08-05 17:37:11 -06:00
|
|
|
static const struct file_operations skel_fops = {
|
2005-04-16 16:20:36 -06:00
|
|
|
.owner = THIS_MODULE,
|
|
|
|
.read = skel_read,
|
|
|
|
.write = skel_write,
|
|
|
|
.open = skel_open,
|
|
|
|
.release = skel_release,
|
2007-05-25 05:42:56 -06:00
|
|
|
.flush = skel_flush,
|
llseek: automatically add .llseek fop
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.
The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.
New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.
The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.
Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.
Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.
===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}
@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}
@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}
@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}
@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};
@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};
@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};
@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};
@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};
// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};
@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};
// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};
// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};
// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};
@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};
// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////
@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};
@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};
@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};
@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-08-15 10:52:59 -06:00
|
|
|
.llseek = noop_llseek,
|
2005-04-16 16:20:36 -06:00
|
|
|
};
|
|
|
|
|
2006-08-14 19:44:29 -06:00
|
|
|
/*
|
2005-04-16 16:20:36 -06:00
|
|
|
* usb class driver info in order to get a minor number from the usb core,
|
2006-01-18 15:36:58 -07:00
|
|
|
* and to have the device registered with the driver core
|
2005-04-16 16:20:36 -06:00
|
|
|
*/
|
|
|
|
static struct usb_class_driver skel_class = {
|
2005-06-20 22:15:16 -06:00
|
|
|
.name = "skel%d",
|
2005-04-16 16:20:36 -06:00
|
|
|
.fops = &skel_fops,
|
|
|
|
.minor_base = USB_SKEL_MINOR_BASE,
|
|
|
|
};
|
|
|
|
|
2009-09-11 17:07:30 -06:00
|
|
|
static int skel_probe(struct usb_interface *interface,
|
|
|
|
const struct usb_device_id *id)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
2006-08-14 19:44:29 -06:00
|
|
|
struct usb_skel *dev;
|
2017-03-17 04:35:47 -06:00
|
|
|
struct usb_endpoint_descriptor *bulk_in, *bulk_out;
|
|
|
|
int retval;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
/* allocate memory for our device state and initialize it */
|
2005-12-21 11:27:29 -07:00
|
|
|
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
|
2016-08-25 11:39:33 -06:00
|
|
|
if (!dev)
|
2017-03-17 04:35:47 -06:00
|
|
|
return -ENOMEM;
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
kref_init(&dev->kref);
|
2005-12-21 11:27:29 -07:00
|
|
|
sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
|
2006-07-01 20:06:36 -06:00
|
|
|
mutex_init(&dev->io_mutex);
|
2007-05-25 05:42:56 -06:00
|
|
|
spin_lock_init(&dev->err_lock);
|
|
|
|
init_usb_anchor(&dev->submitted);
|
2013-03-20 06:47:46 -06:00
|
|
|
init_waitqueue_head(&dev->bulk_in_wait);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
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 */
|
2017-03-17 04:35:47 -06:00
|
|
|
retval = usb_find_common_endpoints(interface->cur_altsetting,
|
|
|
|
&bulk_in, &bulk_out, NULL, NULL);
|
|
|
|
if (retval) {
|
2012-04-27 12:24:45 -06:00
|
|
|
dev_err(&interface->dev,
|
|
|
|
"Could not find both bulk-in and bulk-out endpoints\n");
|
2005-04-16 16:20:36 -06:00
|
|
|
goto error;
|
|
|
|
}
|
|
|
|
|
2017-03-17 04:35:47 -06:00
|
|
|
dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
|
|
|
|
dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
|
|
|
|
dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
|
|
|
|
if (!dev->bulk_in_buffer) {
|
|
|
|
retval = -ENOMEM;
|
|
|
|
goto error;
|
|
|
|
}
|
|
|
|
dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL);
|
|
|
|
if (!dev->bulk_in_urb) {
|
|
|
|
retval = -ENOMEM;
|
|
|
|
goto error;
|
|
|
|
}
|
|
|
|
|
|
|
|
dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
/* 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 */
|
2012-04-27 12:24:45 -06:00
|
|
|
dev_err(&interface->dev,
|
|
|
|
"Not able to get a minor for this device.\n");
|
2005-04-16 16:20:36 -06:00
|
|
|
usb_set_intfdata(interface, NULL);
|
|
|
|
goto error;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* let the user know what node this device is now attached to */
|
2009-02-06 20:38:51 -07:00
|
|
|
dev_info(&interface->dev,
|
|
|
|
"USB Skeleton device now attached to USBSkel-%d",
|
|
|
|
interface->minor);
|
2005-04-16 16:20:36 -06:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
error:
|
2017-03-17 04:35:47 -06:00
|
|
|
/* this frees allocated memory */
|
|
|
|
kref_put(&dev->kref, skel_delete);
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void skel_disconnect(struct usb_interface *interface)
|
|
|
|
{
|
|
|
|
struct usb_skel *dev;
|
|
|
|
int minor = interface->minor;
|
|
|
|
|
|
|
|
dev = usb_get_intfdata(interface);
|
2012-01-24 13:02:38 -07:00
|
|
|
usb_set_intfdata(interface, NULL);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
/* give back our minor */
|
|
|
|
usb_deregister_dev(interface, &skel_class);
|
|
|
|
|
2006-07-01 20:06:36 -06:00
|
|
|
/* prevent more I/O from starting */
|
|
|
|
mutex_lock(&dev->io_mutex);
|
|
|
|
dev->interface = NULL;
|
|
|
|
mutex_unlock(&dev->io_mutex);
|
|
|
|
|
2007-06-11 06:54:02 -06:00
|
|
|
usb_kill_anchored_urbs(&dev->submitted);
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
/* decrement our usage count */
|
|
|
|
kref_put(&dev->kref, skel_delete);
|
|
|
|
|
2009-02-06 20:38:51 -07:00
|
|
|
dev_info(&interface->dev, "USB Skeleton #%d now disconnected", minor);
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
2007-05-25 05:42:56 -06:00
|
|
|
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);
|
2009-09-09 09:06:53 -06:00
|
|
|
usb_kill_urb(dev->bulk_in_urb);
|
2007-05-25 05:42:56 -06:00
|
|
|
}
|
|
|
|
|
2007-06-11 06:55:08 -06:00
|
|
|
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;
|
|
|
|
}
|
|
|
|
|
2009-09-11 17:07:30 -06:00
|
|
|
static int skel_resume(struct usb_interface *intf)
|
2007-06-11 06:55:08 -06:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-06-11 06:55:51 -06:00
|
|
|
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;
|
|
|
|
}
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
static struct usb_driver skel_driver = {
|
|
|
|
.name = "skeleton",
|
|
|
|
.probe = skel_probe,
|
|
|
|
.disconnect = skel_disconnect,
|
2007-06-11 06:55:08 -06:00
|
|
|
.suspend = skel_suspend,
|
|
|
|
.resume = skel_resume,
|
2007-06-11 06:55:51 -06:00
|
|
|
.pre_reset = skel_pre_reset,
|
|
|
|
.post_reset = skel_post_reset,
|
2005-04-16 16:20:36 -06:00
|
|
|
.id_table = skel_table,
|
2007-03-01 06:31:02 -07:00
|
|
|
.supports_autosuspend = 1,
|
2005-04-16 16:20:36 -06:00
|
|
|
};
|
|
|
|
|
2011-11-18 10:34:02 -07:00
|
|
|
module_usb_driver(skel_driver);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
MODULE_LICENSE("GPL");
|