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WSL2-Linux-Kernel/drivers/hid/usbhid/hiddev.c

993 строки
24 KiB
C
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/*
* Copyright (c) 2001 Paul Stewart
* Copyright (c) 2001 Vojtech Pavlik
*
* HID char devices, giving access to raw HID device events.
*
*/
/*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Should you need to contact me, the author, you can do so either by
* e-mail - mail your message to Paul Stewart <stewart@wetlogic.net>
*/
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/input.h>
#include <linux/usb.h>
#include <linux/hid.h>
#include <linux/hiddev.h>
#include <linux/compat.h>
#include "usbhid.h"
#ifdef CONFIG_USB_DYNAMIC_MINORS
#define HIDDEV_MINOR_BASE 0
#define HIDDEV_MINORS 256
#else
#define HIDDEV_MINOR_BASE 96
#define HIDDEV_MINORS 16
#endif
#define HIDDEV_BUFFER_SIZE 2048
struct hiddev {
int exist;
int open;
struct mutex existancelock;
wait_queue_head_t wait;
struct hid_device *hid;
struct list_head list;
spinlock_t list_lock;
};
struct hiddev_list {
struct hiddev_usage_ref buffer[HIDDEV_BUFFER_SIZE];
int head;
int tail;
unsigned flags;
struct fasync_struct *fasync;
struct hiddev *hiddev;
struct list_head node;
struct mutex thread_lock;
};
static struct hiddev *hiddev_table[HIDDEV_MINORS];
/*
* Find a report, given the report's type and ID. The ID can be specified
* indirectly by REPORT_ID_FIRST (which returns the first report of the given
* type) or by (REPORT_ID_NEXT | old_id), which returns the next report of the
* given type which follows old_id.
*/
static struct hid_report *
hiddev_lookup_report(struct hid_device *hid, struct hiddev_report_info *rinfo)
{
unsigned int flags = rinfo->report_id & ~HID_REPORT_ID_MASK;
unsigned int rid = rinfo->report_id & HID_REPORT_ID_MASK;
struct hid_report_enum *report_enum;
struct hid_report *report;
struct list_head *list;
if (rinfo->report_type < HID_REPORT_TYPE_MIN ||
rinfo->report_type > HID_REPORT_TYPE_MAX)
return NULL;
report_enum = hid->report_enum +
(rinfo->report_type - HID_REPORT_TYPE_MIN);
switch (flags) {
case 0: /* Nothing to do -- report_id is already set correctly */
break;
case HID_REPORT_ID_FIRST:
if (list_empty(&report_enum->report_list))
return NULL;
list = report_enum->report_list.next;
report = list_entry(list, struct hid_report, list);
rinfo->report_id = report->id;
break;
case HID_REPORT_ID_NEXT:
report = report_enum->report_id_hash[rid];
if (!report)
return NULL;
list = report->list.next;
if (list == &report_enum->report_list)
return NULL;
report = list_entry(list, struct hid_report, list);
rinfo->report_id = report->id;
break;
default:
return NULL;
}
return report_enum->report_id_hash[rinfo->report_id];
}
/*
* Perform an exhaustive search of the report table for a usage, given its
* type and usage id.
*/
static struct hid_field *
hiddev_lookup_usage(struct hid_device *hid, struct hiddev_usage_ref *uref)
{
int i, j;
struct hid_report *report;
struct hid_report_enum *report_enum;
struct hid_field *field;
if (uref->report_type < HID_REPORT_TYPE_MIN ||
uref->report_type > HID_REPORT_TYPE_MAX)
return NULL;
report_enum = hid->report_enum +
(uref->report_type - HID_REPORT_TYPE_MIN);
list_for_each_entry(report, &report_enum->report_list, list) {
for (i = 0; i < report->maxfield; i++) {
field = report->field[i];
for (j = 0; j < field->maxusage; j++) {
if (field->usage[j].hid == uref->usage_code) {
uref->report_id = report->id;
uref->field_index = i;
uref->usage_index = j;
return field;
}
}
}
}
return NULL;
}
static void hiddev_send_event(struct hid_device *hid,
struct hiddev_usage_ref *uref)
{
struct hiddev *hiddev = hid->hiddev;
struct hiddev_list *list;
unsigned long flags;
spin_lock_irqsave(&hiddev->list_lock, flags);
list_for_each_entry(list, &hiddev->list, node) {
if (uref->field_index != HID_FIELD_INDEX_NONE ||
(list->flags & HIDDEV_FLAG_REPORT) != 0) {
list->buffer[list->head] = *uref;
list->head = (list->head + 1) &
(HIDDEV_BUFFER_SIZE - 1);
kill_fasync(&list->fasync, SIGIO, POLL_IN);
}
}
spin_unlock_irqrestore(&hiddev->list_lock, flags);
wake_up_interruptible(&hiddev->wait);
}
/*
* This is where hid.c calls into hiddev to pass an event that occurred over
* the interrupt pipe
*/
void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
struct hid_usage *usage, __s32 value)
{
unsigned type = field->report_type;
struct hiddev_usage_ref uref;
uref.report_type =
(type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
uref.report_id = field->report->id;
uref.field_index = field->index;
uref.usage_index = (usage - field->usage);
uref.usage_code = usage->hid;
uref.value = value;
hiddev_send_event(hid, &uref);
}
EXPORT_SYMBOL_GPL(hiddev_hid_event);
void hiddev_report_event(struct hid_device *hid, struct hid_report *report)
{
unsigned type = report->type;
struct hiddev_usage_ref uref;
memset(&uref, 0, sizeof(uref));
uref.report_type =
(type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
uref.report_id = report->id;
uref.field_index = HID_FIELD_INDEX_NONE;
hiddev_send_event(hid, &uref);
}
/*
* fasync file op
*/
static int hiddev_fasync(int fd, struct file *file, int on)
{
struct hiddev_list *list = file->private_data;
return fasync_helper(fd, file, on, &list->fasync);
}
/*
* release file op
*/
static int hiddev_release(struct inode * inode, struct file * file)
{
struct hiddev_list *list = file->private_data;
unsigned long flags;
spin_lock_irqsave(&list->hiddev->list_lock, flags);
list_del(&list->node);
spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
if (!--list->hiddev->open) {
if (list->hiddev->exist) {
usbhid_close(list->hiddev->hid);
usbhid_put_power(list->hiddev->hid);
} else {
kfree(list->hiddev);
}
}
kfree(list);
return 0;
}
/*
* open file op
*/
static int hiddev_open(struct inode *inode, struct file *file)
{
struct hiddev_list *list;
int res, i;
/* See comment in hiddev_connect() for BKL explanation */
lock_kernel();
i = iminor(inode) - HIDDEV_MINOR_BASE;
if (i >= HIDDEV_MINORS || i < 0 || !hiddev_table[i])
return -ENODEV;
if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
return -ENOMEM;
mutex_init(&list->thread_lock);
list->hiddev = hiddev_table[i];
file->private_data = list;
/*
* no need for locking because the USB major number
* is shared which usbcore guards against disconnect
*/
if (list->hiddev->exist) {
if (!list->hiddev->open++) {
res = usbhid_open(hiddev_table[i]->hid);
if (res < 0) {
res = -EIO;
goto bail;
}
}
} else {
res = -ENODEV;
goto bail;
}
spin_lock_irq(&list->hiddev->list_lock);
list_add_tail(&list->node, &hiddev_table[i]->list);
spin_unlock_irq(&list->hiddev->list_lock);
if (!list->hiddev->open++)
if (list->hiddev->exist) {
struct hid_device *hid = hiddev_table[i]->hid;
res = usbhid_get_power(hid);
if (res < 0) {
res = -EIO;
goto bail;
}
usbhid_open(hid);
}
unlock_kernel();
return 0;
bail:
file->private_data = NULL;
kfree(list);
unlock_kernel();
return res;
}
/*
* "write" file op
*/
static ssize_t hiddev_write(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
{
return -EINVAL;
}
/*
* "read" file op
*/
static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
{
DEFINE_WAIT(wait);
struct hiddev_list *list = file->private_data;
int event_size;
int retval;
event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
if (count < event_size)
return 0;
/* lock against other threads */
retval = mutex_lock_interruptible(&list->thread_lock);
if (retval)
return -ERESTARTSYS;
while (retval == 0) {
if (list->head == list->tail) {
prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
while (list->head == list->tail) {
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
break;
}
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
if (!list->hiddev->exist) {
retval = -EIO;
break;
}
/* let O_NONBLOCK tasks run */
mutex_unlock(&list->thread_lock);
schedule();
if (mutex_lock_interruptible(&list->thread_lock))
return -EINTR;
set_current_state(TASK_INTERRUPTIBLE);
}
finish_wait(&list->hiddev->wait, &wait);
}
if (retval) {
mutex_unlock(&list->thread_lock);
return retval;
}
while (list->head != list->tail &&
retval + event_size <= count) {
if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) {
struct hiddev_event event;
event.hid = list->buffer[list->tail].usage_code;
event.value = list->buffer[list->tail].value;
if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) {
mutex_unlock(&list->thread_lock);
return -EFAULT;
}
retval += sizeof(struct hiddev_event);
}
} else {
if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
(list->flags & HIDDEV_FLAG_REPORT) != 0) {
if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) {
mutex_unlock(&list->thread_lock);
return -EFAULT;
}
retval += sizeof(struct hiddev_usage_ref);
}
}
list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
}
}
mutex_unlock(&list->thread_lock);
return retval;
}
/*
* "poll" file op
* No kernel lock - fine
*/
static unsigned int hiddev_poll(struct file *file, poll_table *wait)
{
struct hiddev_list *list = file->private_data;
poll_wait(file, &list->hiddev->wait, wait);
if (list->head != list->tail)
return POLLIN | POLLRDNORM;
if (!list->hiddev->exist)
return POLLERR | POLLHUP;
return 0;
}
/*
* "ioctl" file op
*/
static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
{
struct hid_device *hid = hiddev->hid;
struct hiddev_report_info rinfo;
struct hiddev_usage_ref_multi *uref_multi = NULL;
struct hiddev_usage_ref *uref;
struct hid_report *report;
struct hid_field *field;
int i;
uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
if (!uref_multi)
return -ENOMEM;
uref = &uref_multi->uref;
if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
if (copy_from_user(uref_multi, user_arg,
sizeof(*uref_multi)))
goto fault;
} else {
if (copy_from_user(uref, user_arg, sizeof(*uref)))
goto fault;
}
switch (cmd) {
case HIDIOCGUCODE:
rinfo.report_type = uref->report_type;
rinfo.report_id = uref->report_id;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
goto inval;
if (uref->field_index >= report->maxfield)
goto inval;
field = report->field[uref->field_index];
if (uref->usage_index >= field->maxusage)
goto inval;
uref->usage_code = field->usage[uref->usage_index].hid;
if (copy_to_user(user_arg, uref, sizeof(*uref)))
goto fault;
goto goodreturn;
default:
if (cmd != HIDIOCGUSAGE &&
cmd != HIDIOCGUSAGES &&
uref->report_type == HID_REPORT_TYPE_INPUT)
goto inval;
if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
field = hiddev_lookup_usage(hid, uref);
if (field == NULL)
goto inval;
} else {
rinfo.report_type = uref->report_type;
rinfo.report_id = uref->report_id;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
goto inval;
if (uref->field_index >= report->maxfield)
goto inval;
field = report->field[uref->field_index];
if (cmd == HIDIOCGCOLLECTIONINDEX) {
if (uref->usage_index >= field->maxusage)
goto inval;
} else if (uref->usage_index >= field->report_count)
goto inval;
else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
(uref_multi->num_values > HID_MAX_MULTI_USAGES ||
uref->usage_index + uref_multi->num_values > field->report_count))
goto inval;
}
switch (cmd) {
case HIDIOCGUSAGE:
uref->value = field->value[uref->usage_index];
if (copy_to_user(user_arg, uref, sizeof(*uref)))
goto fault;
goto goodreturn;
case HIDIOCSUSAGE:
field->value[uref->usage_index] = uref->value;
goto goodreturn;
case HIDIOCGCOLLECTIONINDEX:
i = field->usage[uref->usage_index].collection_index;
kfree(uref_multi);
return i;
case HIDIOCGUSAGES:
for (i = 0; i < uref_multi->num_values; i++)
uref_multi->values[i] =
field->value[uref->usage_index + i];
if (copy_to_user(user_arg, uref_multi,
sizeof(*uref_multi)))
goto fault;
goto goodreturn;
case HIDIOCSUSAGES:
for (i = 0; i < uref_multi->num_values; i++)
field->value[uref->usage_index + i] =
uref_multi->values[i];
goto goodreturn;
}
goodreturn:
kfree(uref_multi);
return 0;
fault:
kfree(uref_multi);
return -EFAULT;
inval:
kfree(uref_multi);
return -EINVAL;
}
}
static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
{
struct hid_device *hid = hiddev->hid;
struct usb_device *dev = hid_to_usb_dev(hid);
int idx, len;
char *buf;
if (get_user(idx, (int __user *)user_arg))
return -EFAULT;
if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
return -ENOMEM;
if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
kfree(buf);
return -EINVAL;
}
if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
kfree(buf);
return -EFAULT;
}
kfree(buf);
return len;
}
static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct hiddev_list *list = file->private_data;
struct hiddev *hiddev = list->hiddev;
struct hid_device *hid = hiddev->hid;
struct usb_device *dev = hid_to_usb_dev(hid);
struct hiddev_collection_info cinfo;
struct hiddev_report_info rinfo;
struct hiddev_field_info finfo;
struct hiddev_devinfo dinfo;
struct hid_report *report;
struct hid_field *field;
struct usbhid_device *usbhid = hid->driver_data;
void __user *user_arg = (void __user *)arg;
int i, r;
/* Called without BKL by compat methods so no BKL taken */
/* FIXME: Who or what stop this racing with a disconnect ?? */
if (!hiddev->exist)
return -EIO;
switch (cmd) {
case HIDIOCGVERSION:
return put_user(HID_VERSION, (int __user *)arg);
case HIDIOCAPPLICATION:
if (arg < 0 || arg >= hid->maxapplication)
return -EINVAL;
for (i = 0; i < hid->maxcollection; i++)
if (hid->collection[i].type ==
HID_COLLECTION_APPLICATION && arg-- == 0)
break;
if (i == hid->maxcollection)
return -EINVAL;
return hid->collection[i].usage;
case HIDIOCGDEVINFO:
dinfo.bustype = BUS_USB;
dinfo.busnum = dev->bus->busnum;
dinfo.devnum = dev->devnum;
dinfo.ifnum = usbhid->ifnum;
dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
dinfo.num_applications = hid->maxapplication;
if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
return -EFAULT;
return 0;
case HIDIOCGFLAG:
if (put_user(list->flags, (int __user *)arg))
return -EFAULT;
return 0;
case HIDIOCSFLAG:
{
int newflags;
if (get_user(newflags, (int __user *)arg))
return -EFAULT;
if ((newflags & ~HIDDEV_FLAGS) != 0 ||
((newflags & HIDDEV_FLAG_REPORT) != 0 &&
(newflags & HIDDEV_FLAG_UREF) == 0))
return -EINVAL;
list->flags = newflags;
return 0;
}
case HIDIOCGSTRING:
mutex_lock(&hiddev->existancelock);
if (hiddev->exist)
r = hiddev_ioctl_string(hiddev, cmd, user_arg);
else
r = -ENODEV;
mutex_unlock(&hiddev->existancelock);
return r;
case HIDIOCINITREPORT:
mutex_lock(&hiddev->existancelock);
if (!hiddev->exist) {
mutex_unlock(&hiddev->existancelock);
return -ENODEV;
}
usbhid_init_reports(hid);
mutex_unlock(&hiddev->existancelock);
return 0;
case HIDIOCGREPORT:
if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
return -EFAULT;
if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
return -EINVAL;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
return -EINVAL;
mutex_lock(&hiddev->existancelock);
if (hiddev->exist) {
usbhid_submit_report(hid, report, USB_DIR_IN);
usbhid_wait_io(hid);
}
mutex_unlock(&hiddev->existancelock);
return 0;
case HIDIOCSREPORT:
if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
return -EFAULT;
if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
return -EINVAL;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
return -EINVAL;
mutex_lock(&hiddev->existancelock);
if (hiddev->exist) {
usbhid_submit_report(hid, report, USB_DIR_OUT);
usbhid_wait_io(hid);
}
mutex_unlock(&hiddev->existancelock);
return 0;
case HIDIOCGREPORTINFO:
if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
return -EFAULT;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
return -EINVAL;
rinfo.num_fields = report->maxfield;
if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))
return -EFAULT;
return 0;
case HIDIOCGFIELDINFO:
if (copy_from_user(&finfo, user_arg, sizeof(finfo)))
return -EFAULT;
rinfo.report_type = finfo.report_type;
rinfo.report_id = finfo.report_id;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
return -EINVAL;
if (finfo.field_index >= report->maxfield)
return -EINVAL;
field = report->field[finfo.field_index];
memset(&finfo, 0, sizeof(finfo));
finfo.report_type = rinfo.report_type;
finfo.report_id = rinfo.report_id;
finfo.field_index = field->report_count - 1;
finfo.maxusage = field->maxusage;
finfo.flags = field->flags;
finfo.physical = field->physical;
finfo.logical = field->logical;
finfo.application = field->application;
finfo.logical_minimum = field->logical_minimum;
finfo.logical_maximum = field->logical_maximum;
finfo.physical_minimum = field->physical_minimum;
finfo.physical_maximum = field->physical_maximum;
finfo.unit_exponent = field->unit_exponent;
finfo.unit = field->unit;
if (copy_to_user(user_arg, &finfo, sizeof(finfo)))
return -EFAULT;
return 0;
case HIDIOCGUCODE:
/* fall through */
case HIDIOCGUSAGE:
case HIDIOCSUSAGE:
case HIDIOCGUSAGES:
case HIDIOCSUSAGES:
case HIDIOCGCOLLECTIONINDEX:
mutex_lock(&hiddev->existancelock);
if (hiddev->exist)
r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
else
r = -ENODEV;
mutex_unlock(&hiddev->existancelock);
return r;
case HIDIOCGCOLLECTIONINFO:
if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))
return -EFAULT;
if (cinfo.index >= hid->maxcollection)
return -EINVAL;
cinfo.type = hid->collection[cinfo.index].type;
cinfo.usage = hid->collection[cinfo.index].usage;
cinfo.level = hid->collection[cinfo.index].level;
if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))
return -EFAULT;
return 0;
default:
if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
return -EINVAL;
if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
int len;
if (!hid->name)
return 0;
len = strlen(hid->name) + 1;
if (len > _IOC_SIZE(cmd))
len = _IOC_SIZE(cmd);
return copy_to_user(user_arg, hid->name, len) ?
-EFAULT : len;
}
if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
int len;
if (!hid->phys)
return 0;
len = strlen(hid->phys) + 1;
if (len > _IOC_SIZE(cmd))
len = _IOC_SIZE(cmd);
return copy_to_user(user_arg, hid->phys, len) ?
-EFAULT : len;
}
}
return -EINVAL;
}
#ifdef CONFIG_COMPAT
static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
static const struct file_operations hiddev_fops = {
.owner = THIS_MODULE,
.read = hiddev_read,
.write = hiddev_write,
.poll = hiddev_poll,
.open = hiddev_open,
.release = hiddev_release,
.unlocked_ioctl = hiddev_ioctl,
.fasync = hiddev_fasync,
#ifdef CONFIG_COMPAT
.compat_ioctl = hiddev_compat_ioctl,
#endif
};
static char *hiddev_devnode(struct device *dev, mode_t *mode)
{
return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
}
static struct usb_class_driver hiddev_class = {
.name = "hiddev%d",
.devnode = hiddev_devnode,
.fops = &hiddev_fops,
.minor_base = HIDDEV_MINOR_BASE,
};
/*
* This is where hid.c calls us to connect a hid device to the hiddev driver
*/
int hiddev_connect(struct hid_device *hid, unsigned int force)
{
struct hiddev *hiddev;
struct usbhid_device *usbhid = hid->driver_data;
int retval;
if (!force) {
unsigned int i;
for (i = 0; i < hid->maxcollection; i++)
if (hid->collection[i].type ==
HID_COLLECTION_APPLICATION &&
!IS_INPUT_APPLICATION(hid->collection[i].usage))
break;
if (i == hid->maxcollection)
return -1;
}
if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
return -1;
init_waitqueue_head(&hiddev->wait);
INIT_LIST_HEAD(&hiddev->list);
spin_lock_init(&hiddev->list_lock);
mutex_init(&hiddev->existancelock);
hid->hiddev = hiddev;
hiddev->hid = hid;
hiddev->exist = 1;
/*
* BKL here is used to avoid race after usb_register_dev().
* Once the device node has been created, open() could happen on it.
* The code below will then fail, as hiddev_table hasn't been
* updated.
*
* The obvious fix -- introducing mutex to guard hiddev_table[]
* doesn't work, as usb_open() and usb_register_dev() both take
* minor_rwsem, thus we'll have ABBA deadlock.
*
* Before BKL pushdown, usb_open() had been acquiring it in right
* order, so _open() was safe to use it to protect from this race.
* Now the order is different, but AB-BA deadlock still doesn't occur
* as BKL is dropped on schedule() (i.e. while sleeping on
* minor_rwsem). Fugly.
*/
lock_kernel();
retval = usb_register_dev(usbhid->intf, &hiddev_class);
if (retval) {
err_hid("Not able to get a minor for this device.");
hid->hiddev = NULL;
unlock_kernel();
kfree(hiddev);
return -1;
} else {
hid->minor = usbhid->intf->minor;
hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
}
unlock_kernel();
return 0;
}
/*
* This is where hid.c calls us to disconnect a hiddev device from the
* corresponding hid device (usually because the usb device has disconnected)
*/
static struct usb_class_driver hiddev_class;
void hiddev_disconnect(struct hid_device *hid)
{
struct hiddev *hiddev = hid->hiddev;
struct usbhid_device *usbhid = hid->driver_data;
mutex_lock(&hiddev->existancelock);
hiddev->exist = 0;
mutex_unlock(&hiddev->existancelock);
hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL;
usb_deregister_dev(usbhid->intf, &hiddev_class);
if (hiddev->open) {
usbhid_close(hiddev->hid);
wake_up_interruptible(&hiddev->wait);
} else {
kfree(hiddev);
}
}
/* Currently this driver is a USB driver. It's not a conventional one in
* the sense that it doesn't probe at the USB level. Instead it waits to
* be connected by HID through the hiddev_connect / hiddev_disconnect
* routines. The reason to register as a USB device is to gain part of the
* minor number space from the USB major.
*
* In theory, should the HID code be generalized to more than one physical
* medium (say, IEEE 1384), this driver will probably need to register its
* own major number, and in doing so, no longer need to register with USB.
* At that point the probe routine and hiddev_driver struct below will no
* longer be useful.
*/
/* We never attach in this manner, and rely on HID to connect us. This
* is why there is no disconnect routine defined in the usb_driver either.
*/
static int hiddev_usbd_probe(struct usb_interface *intf,
const struct usb_device_id *hiddev_info)
{
return -ENODEV;
}
static /* const */ struct usb_driver hiddev_driver = {
.name = "hiddev",
.probe = hiddev_usbd_probe,
};
int __init hiddev_init(void)
{
return usb_register(&hiddev_driver);
}
void hiddev_exit(void)
{
usb_deregister(&hiddev_driver);
}
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