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