[deliverable/linux.git] / 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/compat.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_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_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 int uhid_hid_output_report(struct hid_device *hid, __u8 *buf,
				  size_t count)
{
	struct uhid_device *uhid = hid->driver_data;
	unsigned long flags;
	struct uhid_event *ev;

	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 = UHID_OUTPUT_REPORT;
	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,
	.parse = uhid_hid_parse,
	.output_report = uhid_hid_output_report,
};

#ifdef CONFIG_COMPAT

/* Apparently we haven't stepped on these rakes enough times yet. */
struct uhid_create_req_compat {
	__u8 name[128];
	__u8 phys[64];
	__u8 uniq[64];

	compat_uptr_t rd_data;
	__u16 rd_size;

	__u16 bus;
	__u32 vendor;
	__u32 product;
	__u32 version;
	__u32 country;
} __attribute__((__packed__));

static int uhid_event_from_user(const char __user *buffer, size_t len,
				struct uhid_event *event)
{
	if (is_compat_task()) {
		u32 type;

		if (get_user(type, buffer))
			return -EFAULT;

		if (type == UHID_CREATE) {
			/*
			 * This is our messed up request with compat pointer.
			 * It is largish (more than 256 bytes) so we better
			 * allocate it from the heap.
			 */
			struct uhid_create_req_compat *compat;

			compat = kzalloc(sizeof(*compat), GFP_KERNEL);
			if (!compat)
				return -ENOMEM;

			buffer += sizeof(type);
			len -= sizeof(type);
			if (copy_from_user(compat, buffer,
					   min(len, sizeof(*compat)))) {
				kfree(compat);
				return -EFAULT;
			}

			/* Shuffle the data over to proper structure */
			event->type = type;

			memcpy(event->u.create.name, compat->name,
				sizeof(compat->name));
			memcpy(event->u.create.phys, compat->phys,
				sizeof(compat->phys));
			memcpy(event->u.create.uniq, compat->uniq,
				sizeof(compat->uniq));

			event->u.create.rd_data = compat_ptr(compat->rd_data);
			event->u.create.rd_size = compat->rd_size;

			event->u.create.bus = compat->bus;
			event->u.create.vendor = compat->vendor;
			event->u.create.product = compat->product;
			event->u.create.version = compat->version;
			event->u.create.country = compat->country;

			kfree(compat);
			return 0;
		}
		/* All others can be copied directly */
	}

	if (copy_from_user(event, buffer, min(len, sizeof(*event))))
		return -EFAULT;

	return 0;
}
#else
static int uhid_event_from_user(const char __user *buffer, size_t len,
				struct uhid_event *event)
{
	if (copy_from_user(event, buffer, min(len, sizeof(*event))))
		return -EFAULT;

	return 0;
}
#endif

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_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));

	ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
	if (ret)
		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		= UHID_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");
MODULE_ALIAS_MISCDEV(UHID_MINOR);
MODULE_ALIAS("devname:" UHID_NAME);
Commit	Line	Data
1ccd7a2a DH	1	/*
	2	* User-space I/O driver support for HID subsystem
	3	* Copyright (c) 2012 David Herrmann
	4	*/
	5
	6	/*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms of the GNU General Public License as published by the Free
	9	* Software Foundation; either version 2 of the License, or (at your option)
	10	* any later version.
	11	*/
	12
	13	#include <linux/atomic.h>
befde022	14	#include <linux/compat.h>
1ccd7a2a DH	15	#include <linux/device.h>
	16	#include <linux/fs.h>
	17	#include <linux/hid.h>
	18	#include <linux/input.h>
	19	#include <linux/miscdevice.h>
	20	#include <linux/module.h>
	21	#include <linux/mutex.h>
	22	#include <linux/poll.h>
	23	#include <linux/sched.h>
	24	#include <linux/spinlock.h>
	25	#include <linux/uhid.h>
	26	#include <linux/wait.h>
	27
	28	#define UHID_NAME "uhid"
ace3d861 DH	29	#define UHID_BUFSIZE 32
	30
	31	struct uhid_device {
d937ae5f	32	struct mutex devlock;
d365c6cf DH	33	bool running;
	34
	35	__u8 *rd_data;
	36	uint rd_size;
	37
ace3d861	38	struct hid_device *hid;
6664ef72	39	struct uhid_event input_buf;
ace3d861 DH	40
	41	wait_queue_head_t waitq;
	42	spinlock_t qlock;
	43	__u8 head;
	44	__u8 tail;
	45	struct uhid_event *outq[UHID_BUFSIZE];
fcfcf0de DH	46
	47	struct mutex report_lock;
	48	wait_queue_head_t report_wait;
	49	atomic_t report_done;
	50	atomic_t report_id;
	51	struct uhid_event report_buf;
ace3d861	52	};
1ccd7a2a DH	53
	54	static struct miscdevice uhid_misc;
	55
ace3d861 DH	56	static void uhid_queue(struct uhid_device uhid, struct uhid_event ev)
	57	{
	58	__u8 newhead;
	59
	60	newhead = (uhid->head + 1) % UHID_BUFSIZE;
	61
	62	if (newhead != uhid->tail) {
	63	uhid->outq[uhid->head] = ev;
	64	uhid->head = newhead;
	65	wake_up_interruptible(&uhid->waitq);
	66	} else {
	67	hid_warn(uhid->hid, "Output queue is full\n");
	68	kfree(ev);
	69	}
	70	}
	71
	72	static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
	73	{
	74	unsigned long flags;
	75	struct uhid_event *ev;
	76
	77	ev = kzalloc(sizeof(*ev), GFP_KERNEL);
	78	if (!ev)
	79	return -ENOMEM;
	80
	81	ev->type = event;
	82
	83	spin_lock_irqsave(&uhid->qlock, flags);
	84	uhid_queue(uhid, ev);
	85	spin_unlock_irqrestore(&uhid->qlock, flags);
	86
	87	return 0;
	88	}
	89
d365c6cf DH	90	static int uhid_hid_start(struct hid_device *hid)
d365c6cf DH	91	{
ec4b7dea DH	92	struct uhid_device *uhid = hid->driver_data;
	93
	94	return uhid_queue_event(uhid, UHID_START);
d365c6cf DH	95	}
	96
	97	static void uhid_hid_stop(struct hid_device *hid)
	98	{
ec4b7dea DH	99	struct uhid_device *uhid = hid->driver_data;
	100
	101	hid->claimed = 0;
	102	uhid_queue_event(uhid, UHID_STOP);
d365c6cf DH	103	}
	104
	105	static int uhid_hid_open(struct hid_device *hid)
	106	{
e7191474 DH	107	struct uhid_device *uhid = hid->driver_data;
	108
	109	return uhid_queue_event(uhid, UHID_OPEN);
d365c6cf DH	110	}
	111
	112	static void uhid_hid_close(struct hid_device *hid)
	113	{
e7191474 DH	114	struct uhid_device *uhid = hid->driver_data;
	115
	116	uhid_queue_event(uhid, UHID_CLOSE);
d365c6cf DH	117	}
d365c6cf DH	118
d365c6cf DH	119	static int uhid_hid_parse(struct hid_device *hid)
d365c6cf DH	120	{
037c061b DH	121	struct uhid_device *uhid = hid->driver_data;
	122
	123	return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
d365c6cf DH	124	}
d365c6cf DH	125
d365c6cf DH	126	static int uhid_hid_output_raw(struct hid_device hid, __u8 buf, size_t count,
	127	unsigned char report_type)
	128	{
3b3baa82 DH	129	struct uhid_device *uhid = hid->driver_data;
	130	__u8 rtype;
	131	unsigned long flags;
	132	struct uhid_event *ev;
	133
	134	switch (report_type) {
	135	case HID_FEATURE_REPORT:
	136	rtype = UHID_FEATURE_REPORT;
	137	break;
	138	case HID_OUTPUT_REPORT:
	139	rtype = UHID_OUTPUT_REPORT;
	140	break;
	141	default:
	142	return -EINVAL;
	143	}
	144
	145	if (count < 1 \|\| count > UHID_DATA_MAX)
	146	return -EINVAL;
	147
	148	ev = kzalloc(sizeof(*ev), GFP_KERNEL);
	149	if (!ev)
	150	return -ENOMEM;
	151
	152	ev->type = UHID_OUTPUT;
	153	ev->u.output.size = count;
	154	ev->u.output.rtype = rtype;
	155	memcpy(ev->u.output.data, buf, count);
	156
	157	spin_lock_irqsave(&uhid->qlock, flags);
	158	uhid_queue(uhid, ev);
	159	spin_unlock_irqrestore(&uhid->qlock, flags);
	160
	161	return count;
d365c6cf DH	162	}
d365c6cf DH	163
596cfdd8 FP	164	static int uhid_hid_output_report(struct hid_device hid, __u8 buf,
	165	size_t count)
	166	{
	167	struct uhid_device *uhid = hid->driver_data;
	168	unsigned long flags;
	169	struct uhid_event *ev;
	170
	171	if (count < 1 \|\| count > UHID_DATA_MAX)
	172	return -EINVAL;
	173
	174	ev = kzalloc(sizeof(*ev), GFP_KERNEL);
	175	if (!ev)
	176	return -ENOMEM;
	177
	178	ev->type = UHID_OUTPUT;
	179	ev->u.output.size = count;
	180	ev->u.output.rtype = UHID_OUTPUT_REPORT;
	181	memcpy(ev->u.output.data, buf, count);
	182
	183	spin_lock_irqsave(&uhid->qlock, flags);
	184	uhid_queue(uhid, ev);
	185	spin_unlock_irqrestore(&uhid->qlock, flags);
	186
	187	return count;
	188	}
	189
d365c6cf DH	190	static struct hid_ll_driver uhid_hid_driver = {
	191	.start = uhid_hid_start,
	192	.stop = uhid_hid_stop,
	193	.open = uhid_hid_open,
	194	.close = uhid_hid_close,
d365c6cf	195	.parse = uhid_hid_parse,
596cfdd8	196	.output_report = uhid_hid_output_report,
d365c6cf DH	197	};
d365c6cf DH	198
befde022 DT	199	#ifdef CONFIG_COMPAT
	200
	201	/* Apparently we haven't stepped on these rakes enough times yet. */
	202	struct uhid_create_req_compat {
	203	__u8 name[128];
	204	__u8 phys[64];
	205	__u8 uniq[64];
	206
	207	compat_uptr_t rd_data;
	208	__u16 rd_size;
	209
	210	__u16 bus;
	211	__u32 vendor;
	212	__u32 product;
	213	__u32 version;
	214	__u32 country;
	215	} __attribute__((__packed__));
	216
	217	static int uhid_event_from_user(const char __user *buffer, size_t len,
	218	struct uhid_event *event)
	219	{
	220	if (is_compat_task()) {
	221	u32 type;
	222
	223	if (get_user(type, buffer))
	224	return -EFAULT;
	225
	226	if (type == UHID_CREATE) {
	227	/*
	228	* This is our messed up request with compat pointer.
	229	* It is largish (more than 256 bytes) so we better
	230	* allocate it from the heap.
	231	*/
	232	struct uhid_create_req_compat *compat;
	233
80897aa7	234	compat = kzalloc(sizeof(*compat), GFP_KERNEL);
befde022 DT	235	if (!compat)
	236	return -ENOMEM;
	237
	238	buffer += sizeof(type);
	239	len -= sizeof(type);
	240	if (copy_from_user(compat, buffer,
	241	min(len, sizeof(*compat)))) {
	242	kfree(compat);
	243	return -EFAULT;
	244	}
	245
	246	/* Shuffle the data over to proper structure */
	247	event->type = type;
	248
	249	memcpy(event->u.create.name, compat->name,
	250	sizeof(compat->name));
	251	memcpy(event->u.create.phys, compat->phys,
	252	sizeof(compat->phys));
	253	memcpy(event->u.create.uniq, compat->uniq,
	254	sizeof(compat->uniq));
	255
	256	event->u.create.rd_data = compat_ptr(compat->rd_data);
	257	event->u.create.rd_size = compat->rd_size;
	258
	259	event->u.create.bus = compat->bus;
	260	event->u.create.vendor = compat->vendor;
	261	event->u.create.product = compat->product;
	262	event->u.create.version = compat->version;
	263	event->u.create.country = compat->country;
	264
	265	kfree(compat);
	266	return 0;
	267	}
	268	/* All others can be copied directly */
	269	}
	270
	271	if (copy_from_user(event, buffer, min(len, sizeof(*event))))
	272	return -EFAULT;
	273
	274	return 0;
	275	}
	276	#else
	277	static int uhid_event_from_user(const char __user *buffer, size_t len,
	278	struct uhid_event *event)
	279	{
	280	if (copy_from_user(event, buffer, min(len, sizeof(*event))))
	281	return -EFAULT;
	282
	283	return 0;
	284	}
	285	#endif
	286
d365c6cf DH	287	static int uhid_dev_create(struct uhid_device *uhid,
	288	const struct uhid_event *ev)
	289	{
	290	struct hid_device *hid;
	291	int ret;
	292
	293	if (uhid->running)
	294	return -EALREADY;
	295
	296	uhid->rd_size = ev->u.create.rd_size;
	297	if (uhid->rd_size <= 0 \|\| uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
	298	return -EINVAL;
	299
	300	uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
	301	if (!uhid->rd_data)
	302	return -ENOMEM;
	303
	304	if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
	305	uhid->rd_size)) {
	306	ret = -EFAULT;
	307	goto err_free;
	308	}
	309
	310	hid = hid_allocate_device();
	311	if (IS_ERR(hid)) {
	312	ret = PTR_ERR(hid);
	313	goto err_free;
	314	}
	315
	316	strncpy(hid->name, ev->u.create.name, 127);
	317	hid->name[127] = 0;
	318	strncpy(hid->phys, ev->u.create.phys, 63);
	319	hid->phys[63] = 0;
	320	strncpy(hid->uniq, ev->u.create.uniq, 63);
	321	hid->uniq[63] = 0;
	322
	323	hid->ll_driver = &uhid_hid_driver;
d365c6cf DH	324	hid->hid_output_raw_report = uhid_hid_output_raw;
	325	hid->bus = ev->u.create.bus;
	326	hid->vendor = ev->u.create.vendor;
	327	hid->product = ev->u.create.product;
	328	hid->version = ev->u.create.version;
	329	hid->country = ev->u.create.country;
	330	hid->driver_data = uhid;
	331	hid->dev.parent = uhid_misc.this_device;
	332
	333	uhid->hid = hid;
	334	uhid->running = true;
	335
	336	ret = hid_add_device(hid);
	337	if (ret) {
	338	hid_err(hid, "Cannot register HID device\n");
	339	goto err_hid;
	340	}
	341
	342	return 0;
	343
	344	err_hid:
	345	hid_destroy_device(hid);
	346	uhid->hid = NULL;
	347	uhid->running = false;
	348	err_free:
	349	kfree(uhid->rd_data);
	350	return ret;
	351	}
	352
	353	static int uhid_dev_destroy(struct uhid_device *uhid)
	354	{
	355	if (!uhid->running)
	356	return -EINVAL;
	357
fcfcf0de	358	/* clear "running" before setting "report_done" */
d365c6cf	359	uhid->running = false;
fcfcf0de DH	360	smp_wmb();
	361	atomic_set(&uhid->report_done, 1);
	362	wake_up_interruptible(&uhid->report_wait);
d365c6cf DH	363
	364	hid_destroy_device(uhid->hid);
	365	kfree(uhid->rd_data);
	366
	367	return 0;
	368	}
	369
5e87a36a DH	370	static int uhid_dev_input(struct uhid_device uhid, struct uhid_event ev)
	371	{
	372	if (!uhid->running)
	373	return -EINVAL;
	374
	375	hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
	376	min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
	377
	378	return 0;
	379	}
	380
fcfcf0de DH	381	static int uhid_dev_feature_answer(struct uhid_device *uhid,
	382	struct uhid_event *ev)
	383	{
	384	unsigned long flags;
	385
	386	if (!uhid->running)
	387	return -EINVAL;
	388
	389	spin_lock_irqsave(&uhid->qlock, flags);
	390
	391	/* id for old report; drop it silently */
	392	if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id)
	393	goto unlock;
	394	if (atomic_read(&uhid->report_done))
	395	goto unlock;
	396
	397	memcpy(&uhid->report_buf, ev, sizeof(*ev));
	398	atomic_set(&uhid->report_done, 1);
	399	wake_up_interruptible(&uhid->report_wait);
	400
	401	unlock:
	402	spin_unlock_irqrestore(&uhid->qlock, flags);
	403	return 0;
	404	}
	405
1ccd7a2a DH	406	static int uhid_char_open(struct inode inode, struct file file)
1ccd7a2a DH	407	{
ace3d861 DH	408	struct uhid_device *uhid;
	409
	410	uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
	411	if (!uhid)
	412	return -ENOMEM;
	413
d937ae5f	414	mutex_init(&uhid->devlock);
fcfcf0de	415	mutex_init(&uhid->report_lock);
ace3d861 DH	416	spin_lock_init(&uhid->qlock);
ace3d861 DH	417	init_waitqueue_head(&uhid->waitq);
fcfcf0de	418	init_waitqueue_head(&uhid->report_wait);
d365c6cf	419	uhid->running = false;
fcfcf0de	420	atomic_set(&uhid->report_done, 1);
ace3d861 DH	421
	422	file->private_data = uhid;
	423	nonseekable_open(inode, file);
	424
1ccd7a2a DH	425	return 0;
	426	}
	427
	428	static int uhid_char_release(struct inode inode, struct file file)
	429	{
ace3d861 DH	430	struct uhid_device *uhid = file->private_data;
	431	unsigned int i;
	432
d365c6cf DH	433	uhid_dev_destroy(uhid);
d365c6cf DH	434
ace3d861 DH	435	for (i = 0; i < UHID_BUFSIZE; ++i)
	436	kfree(uhid->outq[i]);
	437
	438	kfree(uhid);
	439
1ccd7a2a DH	440	return 0;
	441	}
	442
	443	static ssize_t uhid_char_read(struct file file, char __user buffer,
	444	size_t count, loff_t *ppos)
	445	{
d937ae5f DH	446	struct uhid_device *uhid = file->private_data;
	447	int ret;
	448	unsigned long flags;
	449	size_t len;
	450
	451	/* they need at least the "type" member of uhid_event */
	452	if (count < sizeof(__u32))
	453	return -EINVAL;
	454
	455	try_again:
	456	if (file->f_flags & O_NONBLOCK) {
	457	if (uhid->head == uhid->tail)
	458	return -EAGAIN;
	459	} else {
	460	ret = wait_event_interruptible(uhid->waitq,
	461	uhid->head != uhid->tail);
	462	if (ret)
	463	return ret;
	464	}
	465
	466	ret = mutex_lock_interruptible(&uhid->devlock);
	467	if (ret)
	468	return ret;
	469
	470	if (uhid->head == uhid->tail) {
	471	mutex_unlock(&uhid->devlock);
	472	goto try_again;
	473	} else {
	474	len = min(count, sizeof(**uhid->outq));
adefb69b	475	if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
d937ae5f DH	476	ret = -EFAULT;
	477	} else {
	478	kfree(uhid->outq[uhid->tail]);
	479	uhid->outq[uhid->tail] = NULL;
	480
	481	spin_lock_irqsave(&uhid->qlock, flags);
	482	uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
	483	spin_unlock_irqrestore(&uhid->qlock, flags);
	484	}
	485	}
	486
	487	mutex_unlock(&uhid->devlock);
	488	return ret ? ret : len;
1ccd7a2a DH	489	}
	490
	491	static ssize_t uhid_char_write(struct file file, const char __user buffer,
	492	size_t count, loff_t *ppos)
	493	{
6664ef72 DH	494	struct uhid_device *uhid = file->private_data;
	495	int ret;
	496	size_t len;
	497
	498	/* we need at least the "type" member of uhid_event */
	499	if (count < sizeof(__u32))
	500	return -EINVAL;
	501
	502	ret = mutex_lock_interruptible(&uhid->devlock);
	503	if (ret)
	504	return ret;
	505
	506	memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
	507	len = min(count, sizeof(uhid->input_buf));
befde022 DT	508
	509	ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
	510	if (ret)
6664ef72	511	goto unlock;
6664ef72 DH	512
6664ef72 DH	513	switch (uhid->input_buf.type) {
d365c6cf DH	514	case UHID_CREATE:
	515	ret = uhid_dev_create(uhid, &uhid->input_buf);
	516	break;
	517	case UHID_DESTROY:
	518	ret = uhid_dev_destroy(uhid);
	519	break;
5e87a36a DH	520	case UHID_INPUT:
	521	ret = uhid_dev_input(uhid, &uhid->input_buf);
	522	break;
fcfcf0de DH	523	case UHID_FEATURE_ANSWER:
	524	ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
	525	break;
6664ef72 DH	526	default:
	527	ret = -EOPNOTSUPP;
	528	}
	529
	530	unlock:
	531	mutex_unlock(&uhid->devlock);
	532
	533	/* return "count" not "len" to not confuse the caller */
	534	return ret ? ret : count;
1ccd7a2a DH	535	}
	536
	537	static unsigned int uhid_char_poll(struct file file, poll_table wait)
	538	{
1f9dec1e DH	539	struct uhid_device *uhid = file->private_data;
	540
	541	poll_wait(file, &uhid->waitq, wait);
	542
	543	if (uhid->head != uhid->tail)
	544	return POLLIN \| POLLRDNORM;
	545
1ccd7a2a DH	546	return 0;
	547	}
	548
	549	static const struct file_operations uhid_fops = {
	550	.owner = THIS_MODULE,
	551	.open = uhid_char_open,
	552	.release = uhid_char_release,
	553	.read = uhid_char_read,
	554	.write = uhid_char_write,
	555	.poll = uhid_char_poll,
	556	.llseek = no_llseek,
	557	};
	558
	559	static struct miscdevice uhid_misc = {
	560	.fops = &uhid_fops,
19872d20	561	.minor = UHID_MINOR,
1ccd7a2a DH	562	.name = UHID_NAME,
	563	};
	564
	565	static int __init uhid_init(void)
	566	{
	567	return misc_register(&uhid_misc);
	568	}
	569
	570	static void __exit uhid_exit(void)
	571	{
	572	misc_deregister(&uhid_misc);
	573	}
	574
	575	module_init(uhid_init);
	576	module_exit(uhid_exit);
	577	MODULE_LICENSE("GPL");
	578	MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
	579	MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
19872d20	580	MODULE_ALIAS_MISCDEV(UHID_MINOR);
60cbd53e	581	MODULE_ALIAS("devname:" UHID_NAME);