linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * USB Skeleton driver - 2.2

 *

 * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)

 *

 * 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/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  0xfff0

#define USB_SKEL_PRODUCT_ID 0xfff0

​

/* 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 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 */

    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 */

};