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