summaryrefslogtreecommitdiff
path: root/drivers/nfc/virtual_ncidev.c
blob: 85c06dbb2c4498008e785ff52df039ab7d1f0c11 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Virtual NCI device simulation driver
 *
 * Copyright (C) 2020 Samsung Electrnoics
 * Bongsu Jeon <bongsu.jeon@samsung.com>
 */

#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);
		kfree_skb(skb);
		return 0;
	}

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

	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 <bongsu.jeon@samsung.com>");