- 根目录:
- drivers
- hid
- uhid.c
/*
* User-space I/O driver support for HID subsystem
* Copyright (c) 2012 David Herrmann
*/
/*
* 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.
*/
#include <linux/atomic.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/hid.h>
#include <linux/input.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/uhid.h>
#include <linux/wait.h>
#define UHID_NAME "uhid"
#define UHID_BUFSIZE 32
struct uhid_device {
struct mutex devlock;
bool running;
__u8 *rd_data;
uint rd_size;
struct hid_device *hid;
struct uhid_event input_buf;
wait_queue_head_t waitq;
spinlock_t qlock;
__u8 head;
__u8 tail;
struct uhid_event *outq[UHID_BUFSIZE];
struct mutex report_lock;
wait_queue_head_t report_wait;
atomic_t report_done;
atomic_t report_id;
struct uhid_event report_buf;
};
static struct miscdevice uhid_misc;
static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
{
__u8 newhead;
newhead = (uhid->head + 1) % UHID_BUFSIZE;
if (newhead != uhid->tail) {
uhid->outq[uhid->head] = ev;
uhid->head = newhead;
wake_up_interruptible(&uhid->waitq);
} else {
hid_warn(uhid->hid, "Output queue is full\n");
kfree(ev);
}
}
static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
{
unsigned long flags;
struct uhid_event *ev;
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
if (!ev)
return -ENOMEM;
ev->type = event;
spin_lock_irqsave(&uhid->qlock, flags);
uhid_queue(uhid, ev);
spin_unlock_irqrestore(&uhid->qlock, flags);
return 0;
}
static int uhid_hid_start(struct hid_device *hid)
{
struct uhid_device *uhid = hid->driver_data;
return uhid_queue_event(uhid, UHID_START);
}
static void uhid_hid_stop(struct hid_device *hid)
{
struct uhid_device *uhid = hid->driver_data;
hid->claimed = 0;
uhid_queue_event(uhid, UHID_STOP);
}
static int uhid_hid_open(struct hid_device *hid)
{
struct uhid_device *uhid = hid->driver_data;
return uhid_queue_event(uhid, UHID_OPEN);
}
static void uhid_hid_close(struct hid_device *hid)
{
struct uhid_device *uhid = hid->driver_data;
uhid_queue_event(uhid, UHID_CLOSE);
}
static int uhid_hid_input(struct input_dev *input, unsigned int type,
unsigned int code, int value)
{
struct hid_device *hid = input_get_drvdata(input);
struct uhid_device *uhid = hid->driver_data;
unsigned long flags;
struct uhid_event *ev;
ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
if (!ev)
return -ENOMEM;
ev->type = UHID_OUTPUT_EV;
ev->u.output_ev.type = type;
ev->u.output_ev.code = code;
ev->u.output_ev.value = value;
spin_lock_irqsave(&uhid->qlock, flags);
uhid_queue(uhid, ev);
spin_unlock_irqrestore(&uhid->qlock, flags);
return 0;
}
static int uhid_hid_parse(struct hid_device *hid)
{
struct uhid_device *uhid = hid->driver_data;
return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
}
static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
__u8 *buf, size_t count, unsigned char rtype)
{
struct uhid_device *uhid = hid->driver_data;
__u8 report_type;
struct uhid_event *ev;
unsigned long flags;
int ret;
size_t uninitialized_var(len);
struct uhid_feature_answer_req *req;
if (!uhid->running)
return -EIO;
switch (rtype) {
case HID_FEATURE_REPORT:
report_type = UHID_FEATURE_REPORT;
break;
case HID_OUTPUT_REPORT:
report_type = UHID_OUTPUT_REPORT;
break;
case HID_INPUT_REPORT:
report_type = UHID_INPUT_REPORT;
break;
default:
return -EINVAL;
}
ret = mutex_lock_interruptible(&uhid->report_lock);
if (ret)
return ret;
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
if (!ev) {
ret = -ENOMEM;
goto unlock;
}
spin_lock_irqsave(&uhid->qlock, flags);
ev->type = UHID_FEATURE;
ev->u.feature.id = atomic_inc_return(&uhid->report_id);
ev->u.feature.rnum = rnum;
ev->u.feature.rtype = report_type;
atomic_set(&uhid->report_done, 0);
uhid_queue(uhid, ev);
spin_unlock_irqrestore(&uhid->qlock, flags);
ret = wait_event_interruptible_timeout(uhid->report_wait,
atomic_read(&uhid->report_done), 5 * HZ);
/*
* Make sure "uhid->running" is cleared on shutdown before
* "uhid->report_done" is set.
*/
smp_rmb();
if (!ret || !uhid->running) {
ret = -EIO;
} else if (ret < 0) {
ret = -ERESTARTSYS;
} else {
spin_lock_irqsave(&uhid->qlock, flags);
req = &uhid->report_buf.u.feature_answer;
if (req->err) {
ret = -EIO;
} else {
ret = 0;
len = min(count,
min_t(size_t, req->size, UHID_DATA_MAX));
memcpy(buf, req->data, len);
}
spin_unlock_irqrestore(&uhid->qlock, flags);
}
atomic_set(&uhid->report_done, 1);
unlock:
mutex_unlock(&uhid->report_lock);
return ret ? ret : len;
}
static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
unsigned char report_type)
{
struct uhid_device *uhid = hid->driver_data;
__u8 rtype;
unsigned long flags;
struct uhid_event *ev;
switch (report_type) {
case HID_FEATURE_REPORT:
rtype = UHID_FEATURE_REPORT;
break;
case HID_OUTPUT_REPORT:
rtype = UHID_OUTPUT_REPORT;
break;
default:
return -EINVAL;
}
if (count < 1 || count > UHID_DATA_MAX)
return -EINVAL;
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
if (!ev)
return -ENOMEM;
ev->type = UHID_OUTPUT;
ev->u.output.size = count;
ev->u.output.rtype = rtype;
memcpy(ev->u.output.data, buf, count);
spin_lock_irqsave(&uhid->qlock, flags);
uhid_queue(uhid, ev);
spin_unlock_irqrestore(&uhid->qlock, flags);
return count;
}
static struct hid_ll_driver uhid_hid_driver = {
.start = uhid_hid_start,
.stop = uhid_hid_stop,
.open = uhid_hid_open,
.close = uhid_hid_close,
.hidinput_input_event = uhid_hid_input,
.parse = uhid_hid_parse,
};
static int uhid_dev_create(struct uhid_device *uhid,
const struct uhid_event *ev)
{
struct hid_device *hid;
int ret;
if (uhid->running)
return -EALREADY;
uhid->rd_size = ev->u.create.rd_size;
if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
return -EINVAL;
uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
if (!uhid->rd_data)
return -ENOMEM;
if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
uhid->rd_size)) {
ret = -EFAULT;
goto err_free;
}
hid = hid_allocate_device();
if (IS_ERR(hid)) {
ret = PTR_ERR(hid);
goto err_free;
}
strncpy(hid->name, ev->u.create.name, 127);
hid->name[127] = 0;
strncpy(hid->phys, ev->u.create.phys, 63);
hid->phys[63] = 0;
strncpy(hid->uniq, ev->u.create.uniq, 63);
hid->uniq[63] = 0;
hid->ll_driver = &uhid_hid_driver;
hid->hid_get_raw_report = uhid_hid_get_raw;
hid->hid_output_raw_report = uhid_hid_output_raw;
hid->bus = ev->u.create.bus;
hid->vendor = ev->u.create.vendor;
hid->product = ev->u.create.product;
hid->version = ev->u.create.version;
hid->country = ev->u.create.country;
hid->driver_data = uhid;
hid->dev.parent = uhid_misc.this_device;
uhid->hid = hid;
uhid->running = true;
ret = hid_add_device(hid);
if (ret) {
hid_err(hid, "Cannot register HID device\n");
goto err_hid;
}
return 0;
err_hid:
hid_destroy_device(hid);
uhid->hid = NULL;
uhid->running = false;
err_free:
kfree(uhid->rd_data);
return ret;
}
static int uhid_dev_destroy(struct uhid_device *uhid)
{
if (!uhid->running)
return -EINVAL;
/* clear "running" before setting "report_done" */
uhid->running = false;
smp_wmb();
atomic_set(&uhid->report_done, 1);
wake_up_interruptible(&uhid->report_wait);
hid_destroy_device(uhid->hid);
kfree(uhid->rd_data);
return 0;
}
static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
{
if (!uhid->running)
return -EINVAL;
hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
return 0;
}
static int uhid_dev_feature_answer(struct uhid_device *uhid,
struct uhid_event *ev)
{
unsigned long flags;
if (!uhid->running)
return -EINVAL;
spin_lock_irqsave(&uhid->qlock, flags);
/* id for old report; drop it silently */
if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id)
goto unlock;
if (atomic_read(&uhid->report_done))
goto unlock;
memcpy(&uhid->report_buf, ev, sizeof(*ev));
atomic_set(&uhid->report_done, 1);
wake_up_interruptible(&uhid->report_wait);
unlock:
spin_unlock_irqrestore(&uhid->qlock, flags);
return 0;
}
static int uhid_char_open(struct inode *inode, struct file *file)
{
struct uhid_device *uhid;
uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
if (!uhid)
return -ENOMEM;
mutex_init(&uhid->devlock);
mutex_init(&uhid->report_lock);
spin_lock_init(&uhid->qlock);
init_waitqueue_head(&uhid->waitq);
init_waitqueue_head(&uhid->report_wait);
uhid->running = false;
atomic_set(&uhid->report_done, 1);
file->private_data = uhid;
nonseekable_open(inode, file);
return 0;
}
static int uhid_char_release(struct inode *inode, struct file *file)
{
struct uhid_device *uhid = file->private_data;
unsigned int i;
uhid_dev_destroy(uhid);
for (i = 0; i < UHID_BUFSIZE; ++i)
kfree(uhid->outq[i]);
kfree(uhid);
return 0;
}
static ssize_t uhid_char_read(struct file *file, char __user *buffer,
size_t count, loff_t *ppos)
{
struct uhid_device *uhid = file->private_data;
int ret;
unsigned long flags;
size_t len;
/* they need at least the "type" member of uhid_event */
if (count < sizeof(__u32))
return -EINVAL;
try_again:
if (file->f_flags & O_NONBLOCK) {
if (uhid->head == uhid->tail)
return -EAGAIN;
} else {
ret = wait_event_interruptible(uhid->waitq,
uhid->head != uhid->tail);
if (ret)
return ret;
}
ret = mutex_lock_interruptible(&uhid->devlock);
if (ret)
return ret;
if (uhid->head == uhid->tail) {
mutex_unlock(&uhid->devlock);
goto try_again;
} else {
len = min(count, sizeof(**uhid->outq));
if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
ret = -EFAULT;
} else {
kfree(uhid->outq[uhid->tail]);
uhid->outq[uhid->tail] = NULL;
spin_lock_irqsave(&uhid->qlock, flags);
uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
spin_unlock_irqrestore(&uhid->qlock, flags);
}
}
mutex_unlock(&uhid->devlock);
return ret ? ret : len;
}
static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
struct uhid_device *uhid = file->private_data;
int ret;
size_t len;
/* we need at least the "type" member of uhid_event */
if (count < sizeof(__u32))
return -EINVAL;
ret = mutex_lock_interruptible(&uhid->devlock);
if (ret)
return ret;
memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
len = min(count, sizeof(uhid->input_buf));
if (copy_from_user(&uhid->input_buf, buffer, len)) {
ret = -EFAULT;
goto unlock;
}
switch (uhid->input_buf.type) {
case UHID_CREATE:
ret = uhid_dev_create(uhid, &uhid->input_buf);
break;
case UHID_DESTROY:
ret = uhid_dev_destroy(uhid);
break;
case UHID_INPUT:
ret = uhid_dev_input(uhid, &uhid->input_buf);
break;
case UHID_FEATURE_ANSWER:
ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
break;
default:
ret = -EOPNOTSUPP;
}
unlock:
mutex_unlock(&uhid->devlock);
/* return "count" not "len" to not confuse the caller */
return ret ? ret : count;
}
static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
{
struct uhid_device *uhid = file->private_data;
poll_wait(file, &uhid->waitq, wait);
if (uhid->head != uhid->tail)
return POLLIN | POLLRDNORM;
return 0;
}
static const struct file_operations uhid_fops = {
.owner = THIS_MODULE,
.open = uhid_char_open,
.release = uhid_char_release,
.read = uhid_char_read,
.write = uhid_char_write,
.poll = uhid_char_poll,
.llseek = no_llseek,
};
static struct miscdevice uhid_misc = {
.fops = &uhid_fops,
.minor = MISC_DYNAMIC_MINOR,
.name = UHID_NAME,
};
static int __init uhid_init(void)
{
return misc_register(&uhid_misc);
}
static void __exit uhid_exit(void)
{
misc_deregister(&uhid_misc);
}
module_init(uhid_init);
module_exit(uhid_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");