[linux.git] / drivers / nfc / virtual_ncidev.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Virtual NCI device simulation driver
 *
 * Copyright (C) 2020 Samsung Electrnoics
 * Bongsu Jeon <[email protected]>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/mutex.h>
#include <linux/wait.h>
#include <net/nfc/nci_core.h>

enum virtual_ncidev_mode {
	virtual_ncidev_enabled,
	virtual_ncidev_disabled,
	virtual_ncidev_disabling,
};

#define IOCTL_GET_NCIDEV_IDX    0
#define VIRTUAL_NFC_PROTOCOLS	(NFC_PROTO_JEWEL_MASK | \
				 NFC_PROTO_MIFARE_MASK | \
				 NFC_PROTO_FELICA_MASK | \
				 NFC_PROTO_ISO14443_MASK | \
				 NFC_PROTO_ISO14443_B_MASK | \
				 NFC_PROTO_ISO15693_MASK)

static enum virtual_ncidev_mode state;
static DECLARE_WAIT_QUEUE_HEAD(wq);
static struct miscdevice miscdev;
static struct sk_buff *send_buff;
static struct nci_dev *ndev;
static DEFINE_MUTEX(nci_mutex);

static int virtual_nci_open(struct nci_dev *ndev)
{
	return 0;
}

static int virtual_nci_close(struct nci_dev *ndev)
{
	mutex_lock(&nci_mutex);
	kfree_skb(send_buff);
	send_buff = NULL;
	mutex_unlock(&nci_mutex);

	return 0;
}

static int virtual_nci_send(struct nci_dev *ndev, struct sk_buff *skb)
{
	mutex_lock(&nci_mutex);
	if (state != virtual_ncidev_enabled) {
		mutex_unlock(&nci_mutex);
		return 0;
	}

	if (send_buff) {
		mutex_unlock(&nci_mutex);
		return -1;
	}
	send_buff = skb_copy(skb, GFP_KERNEL);
	mutex_unlock(&nci_mutex);
	wake_up_interruptible(&wq);

	return 0;
}

static const struct nci_ops virtual_nci_ops = {
	.open = virtual_nci_open,
	.close = virtual_nci_close,
	.send = virtual_nci_send
};

static ssize_t virtual_ncidev_read(struct file *file, char __user *buf,
				   size_t count, loff_t *ppos)
{
	size_t actual_len;

	mutex_lock(&nci_mutex);
	while (!send_buff) {
		mutex_unlock(&nci_mutex);
		if (wait_event_interruptible(wq, send_buff))
			return -EFAULT;
		mutex_lock(&nci_mutex);
	}

	actual_len = min_t(size_t, count, send_buff->len);

	if (copy_to_user(buf, send_buff->data, actual_len)) {
		mutex_unlock(&nci_mutex);
		return -EFAULT;
	}

	skb_pull(send_buff, actual_len);
	if (send_buff->len == 0) {
		consume_skb(send_buff);
		send_buff = NULL;
	}
	mutex_unlock(&nci_mutex);

	return actual_len;
}

static ssize_t virtual_ncidev_write(struct file *file,
				    const char __user *buf,
				    size_t count, loff_t *ppos)
{
	struct sk_buff *skb;

	skb = alloc_skb(count, GFP_KERNEL);
	if (!skb)
		return -ENOMEM;

	if (copy_from_user(skb_put(skb, count), buf, count)) {
		kfree_skb(skb);
		return -EFAULT;
	}

	nci_recv_frame(ndev, skb);
	return count;
}

static int virtual_ncidev_open(struct inode *inode, struct file *file)
{
	int ret = 0;

	mutex_lock(&nci_mutex);
	if (state != virtual_ncidev_disabled) {
		mutex_unlock(&nci_mutex);
		return -EBUSY;
	}

	ndev = nci_allocate_device(&virtual_nci_ops, VIRTUAL_NFC_PROTOCOLS,
				   0, 0);
	if (!ndev) {
		mutex_unlock(&nci_mutex);
		return -ENOMEM;
	}

	ret = nci_register_device(ndev);
	if (ret < 0) {
		nci_free_device(ndev);
		mutex_unlock(&nci_mutex);
		return ret;
	}
	state = virtual_ncidev_enabled;
	mutex_unlock(&nci_mutex);

	return 0;
}

static int virtual_ncidev_close(struct inode *inode, struct file *file)
{
	mutex_lock(&nci_mutex);

	if (state == virtual_ncidev_enabled) {
		state = virtual_ncidev_disabling;
		mutex_unlock(&nci_mutex);

		nci_unregister_device(ndev);
		nci_free_device(ndev);

		mutex_lock(&nci_mutex);
	}

	state = virtual_ncidev_disabled;
	mutex_unlock(&nci_mutex);

	return 0;
}

static long virtual_ncidev_ioctl(struct file *flip, unsigned int cmd,
				 unsigned long arg)
{
	const struct nfc_dev *nfc_dev = ndev->nfc_dev;
	void __user *p = (void __user *)arg;

	if (cmd != IOCTL_GET_NCIDEV_IDX)
		return -ENOTTY;

	if (copy_to_user(p, &nfc_dev->idx, sizeof(nfc_dev->idx)))
		return -EFAULT;

	return 0;
}

static const struct file_operations virtual_ncidev_fops = {
	.owner = THIS_MODULE,
	.read = virtual_ncidev_read,
	.write = virtual_ncidev_write,
	.open = virtual_ncidev_open,
	.release = virtual_ncidev_close,
	.unlocked_ioctl = virtual_ncidev_ioctl
};

static int __init virtual_ncidev_init(void)
{
	state = virtual_ncidev_disabled;
	miscdev.minor = MISC_DYNAMIC_MINOR;
	miscdev.name = "virtual_nci";
	miscdev.fops = &virtual_ncidev_fops;
	miscdev.mode = 0600;

	return misc_register(&miscdev);
}

static void __exit virtual_ncidev_exit(void)
{
	misc_deregister(&miscdev);
}

module_init(virtual_ncidev_init);
module_exit(virtual_ncidev_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Virtual NCI device simulation driver");
MODULE_AUTHOR("Bongsu Jeon <[email protected]>");
Commit	Line	Data
e624e6c3 BJ	1	// SPDX-License-Identifier: GPL-2.0-or-later
	2	/*
	3	* Virtual NCI device simulation driver
	4	*
	5	* Copyright (C) 2020 Samsung Electrnoics
	6	* Bongsu Jeon <[email protected]>
	7	*/
	8
	9	#include <linux/kernel.h>
	10	#include <linux/module.h>
	11	#include <linux/miscdevice.h>
	12	#include <linux/mutex.h>
8675569d	13	#include <linux/wait.h>
e624e6c3 BJ	14	#include <net/nfc/nci_core.h>
	15
	16	enum virtual_ncidev_mode {
	17	virtual_ncidev_enabled,
	18	virtual_ncidev_disabled,
	19	virtual_ncidev_disabling,
	20	};
	21
	22	#define IOCTL_GET_NCIDEV_IDX 0
	23	#define VIRTUAL_NFC_PROTOCOLS (NFC_PROTO_JEWEL_MASK \| \
	24	NFC_PROTO_MIFARE_MASK \| \
	25	NFC_PROTO_FELICA_MASK \| \
	26	NFC_PROTO_ISO14443_MASK \| \
	27	NFC_PROTO_ISO14443_B_MASK \| \
	28	NFC_PROTO_ISO15693_MASK)
	29
	30	static enum virtual_ncidev_mode state;
8675569d	31	static DECLARE_WAIT_QUEUE_HEAD(wq);
e624e6c3 BJ	32	static struct miscdevice miscdev;
	33	static struct sk_buff *send_buff;
	34	static struct nci_dev *ndev;
	35	static DEFINE_MUTEX(nci_mutex);
	36
	37	static int virtual_nci_open(struct nci_dev *ndev)
	38	{
	39	return 0;
	40	}
	41
	42	static int virtual_nci_close(struct nci_dev *ndev)
	43	{
	44	mutex_lock(&nci_mutex);
	45	kfree_skb(send_buff);
	46	send_buff = NULL;
	47	mutex_unlock(&nci_mutex);
	48
	49	return 0;
	50	}
	51
	52	static int virtual_nci_send(struct nci_dev ndev, struct sk_buff skb)
	53	{
	54	mutex_lock(&nci_mutex);
	55	if (state != virtual_ncidev_enabled) {
	56	mutex_unlock(&nci_mutex);
	57	return 0;
	58	}
	59
	60	if (send_buff) {
	61	mutex_unlock(&nci_mutex);
	62	return -1;
	63	}
	64	send_buff = skb_copy(skb, GFP_KERNEL);
	65	mutex_unlock(&nci_mutex);
8675569d	66	wake_up_interruptible(&wq);
e624e6c3 BJ	67
	68	return 0;
	69	}
	70
b9c28286	71	static const struct nci_ops virtual_nci_ops = {
e624e6c3 BJ	72	.open = virtual_nci_open,
	73	.close = virtual_nci_close,
	74	.send = virtual_nci_send
	75	};
	76
	77	static ssize_t virtual_ncidev_read(struct file file, char __user buf,
	78	size_t count, loff_t *ppos)
	79	{
	80	size_t actual_len;
	81
	82	mutex_lock(&nci_mutex);
8675569d	83	while (!send_buff) {
e624e6c3	84	mutex_unlock(&nci_mutex);
8675569d BJ	85	if (wait_event_interruptible(wq, send_buff))
	86	return -EFAULT;
	87	mutex_lock(&nci_mutex);
e624e6c3 BJ	88	}
	89
	90	actual_len = min_t(size_t, count, send_buff->len);
	91
	92	if (copy_to_user(buf, send_buff->data, actual_len)) {
	93	mutex_unlock(&nci_mutex);
	94	return -EFAULT;
	95	}
	96
	97	skb_pull(send_buff, actual_len);
	98	if (send_buff->len == 0) {
	99	consume_skb(send_buff);
	100	send_buff = NULL;
	101	}
	102	mutex_unlock(&nci_mutex);
	103
	104	return actual_len;
	105	}
	106
	107	static ssize_t virtual_ncidev_write(struct file *file,
	108	const char __user *buf,
	109	size_t count, loff_t *ppos)
	110	{
	111	struct sk_buff *skb;
	112
	113	skb = alloc_skb(count, GFP_KERNEL);
	114	if (!skb)
	115	return -ENOMEM;
	116
	117	if (copy_from_user(skb_put(skb, count), buf, count)) {
	118	kfree_skb(skb);
	119	return -EFAULT;
	120	}
	121
	122	nci_recv_frame(ndev, skb);
	123	return count;
	124	}
	125
	126	static int virtual_ncidev_open(struct inode inode, struct file file)
	127	{
	128	int ret = 0;
	129
	130	mutex_lock(&nci_mutex);
	131	if (state != virtual_ncidev_disabled) {
	132	mutex_unlock(&nci_mutex);
	133	return -EBUSY;
	134	}
	135
	136	ndev = nci_allocate_device(&virtual_nci_ops, VIRTUAL_NFC_PROTOCOLS,
	137	0, 0);
	138	if (!ndev) {
	139	mutex_unlock(&nci_mutex);
	140	return -ENOMEM;
	141	}
	142
	143	ret = nci_register_device(ndev);
	144	if (ret < 0) {
	145	nci_free_device(ndev);
	146	mutex_unlock(&nci_mutex);
	147	return ret;
	148	}
	149	state = virtual_ncidev_enabled;
	150	mutex_unlock(&nci_mutex);
	151
152	return 0;
153	}
154
155	static int virtual_ncidev_close(struct inode inode, struct file file)
156	{
157	mutex_lock(&nci_mutex);
158
159	if (state == virtual_ncidev_enabled) {
160	state = virtual_ncidev_disabling;
161	mutex_unlock(&nci_mutex);
162
163	nci_unregister_device(ndev);
164	nci_free_device(ndev);
165
166	mutex_lock(&nci_mutex);
167	}
168
169	state = virtual_ncidev_disabled;
170	mutex_unlock(&nci_mutex);
171
172	return 0;
173	}
174
175	static long virtual_ncidev_ioctl(struct file *flip, unsigned int cmd,
176	unsigned long arg)
177	{
83428dbb	178	const struct nfc_dev *nfc_dev = ndev->nfc_dev;
e624e6c3 BJ	179	void __user p = (void __user )arg;
	180
	181	if (cmd != IOCTL_GET_NCIDEV_IDX)
	182	return -ENOTTY;
	183
	184	if (copy_to_user(p, &nfc_dev->idx, sizeof(nfc_dev->idx)))
	185	return -EFAULT;
	186
	187	return 0;
	188	}
	189
	190	static const struct file_operations virtual_ncidev_fops = {
	191	.owner = THIS_MODULE,
	192	.read = virtual_ncidev_read,
	193	.write = virtual_ncidev_write,
	194	.open = virtual_ncidev_open,
	195	.release = virtual_ncidev_close,
	196	.unlocked_ioctl = virtual_ncidev_ioctl
	197	};
	198
	199	static int __init virtual_ncidev_init(void)
	200	{
	201	state = virtual_ncidev_disabled;
	202	miscdev.minor = MISC_DYNAMIC_MINOR;
	203	miscdev.name = "virtual_nci";
	204	miscdev.fops = &virtual_ncidev_fops;
c26381f9	205	miscdev.mode = 0600;
e624e6c3 BJ	206
	207	return misc_register(&miscdev);
	208	}
	209
	210	static void __exit virtual_ncidev_exit(void)
	211	{
	212	misc_deregister(&miscdev);
	213	}
	214
	215	module_init(virtual_ncidev_init);
	216	module_exit(virtual_ncidev_exit);
	217
	218	MODULE_LICENSE("GPL");
	219	MODULE_DESCRIPTION("Virtual NCI device simulation driver");
	220	MODULE_AUTHOR("Bongsu Jeon <[email protected]>");