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 | bool running; |
30 | }; |
31 | |
32 | static 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 | |
40 | static 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(skb: vdev->send_buff); |
46 | vdev->send_buff = NULL; |
47 | vdev->running = false; |
48 | mutex_unlock(lock: &vdev->mtx); |
49 | |
50 | return 0; |
51 | } |
52 | |
53 | static 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(lock: &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(lock: &vdev->mtx); |
66 | kfree_skb(skb); |
67 | return -1; |
68 | } |
69 | mutex_unlock(lock: &vdev->mtx); |
70 | wake_up_interruptible(&vdev->wq); |
71 | consume_skb(skb); |
72 | |
73 | return 0; |
74 | } |
75 | |
76 | static const struct nci_ops virtual_nci_ops = { |
77 | .open = virtual_nci_open, |
78 | .close = virtual_nci_close, |
79 | .send = virtual_nci_send |
80 | }; |
81 | |
82 | static 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(lock: &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(to: buf, from: vdev->send_buff->data, n: actual_len)) { |
99 | mutex_unlock(lock: &vdev->mtx); |
100 | return -EFAULT; |
101 | } |
102 | |
103 | skb_pull(skb: vdev->send_buff, len: actual_len); |
104 | if (vdev->send_buff->len == 0) { |
105 | consume_skb(skb: vdev->send_buff); |
106 | vdev->send_buff = NULL; |
107 | } |
108 | mutex_unlock(lock: &vdev->mtx); |
109 | |
110 | return actual_len; |
111 | } |
112 | |
113 | static 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(size: count, GFP_KERNEL); |
121 | if (!skb) |
122 | return -ENOMEM; |
123 | |
124 | if (copy_from_user(to: skb_put(skb, len: count), from: buf, n: count)) { |
125 | kfree_skb(skb); |
126 | return -EFAULT; |
127 | } |
128 | |
129 | nci_recv_frame(ndev: vdev->ndev, skb); |
130 | return count; |
131 | } |
132 | |
133 | static 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(size: sizeof(*vdev), GFP_KERNEL); |
139 | if (!vdev) |
140 | return -ENOMEM; |
141 | vdev->ndev = nci_allocate_device(ops: &virtual_nci_ops, |
142 | VIRTUAL_NFC_PROTOCOLS, tx_headroom: 0, tx_tailroom: 0); |
143 | if (!vdev->ndev) { |
144 | kfree(objp: 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(ndev: vdev->ndev, data: vdev); |
152 | |
153 | ret = nci_register_device(ndev: vdev->ndev); |
154 | if (ret < 0) { |
155 | nci_free_device(ndev: vdev->ndev); |
156 | mutex_destroy(lock: &vdev->mtx); |
157 | kfree(objp: vdev); |
158 | return ret; |
159 | } |
160 | |
161 | return 0; |
162 | } |
163 | |
164 | static 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(ndev: vdev->ndev); |
169 | nci_free_device(ndev: vdev->ndev); |
170 | mutex_destroy(lock: &vdev->mtx); |
171 | kfree(objp: vdev); |
172 | |
173 | return 0; |
174 | } |
175 | |
176 | static 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(to: p, from: &nfc_dev->idx, n: sizeof(nfc_dev->idx))) |
187 | return -EFAULT; |
188 | |
189 | return 0; |
190 | } |
191 | |
192 | static 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 | }; |
200 | |
201 | static struct miscdevice miscdev = { |
202 | .minor = MISC_DYNAMIC_MINOR, |
203 | .name = "virtual_nci" , |
204 | .fops = &virtual_ncidev_fops, |
205 | .mode = 0600, |
206 | }; |
207 | |
208 | module_misc_device(miscdev); |
209 | |
210 | MODULE_LICENSE("GPL" ); |
211 | MODULE_DESCRIPTION("Virtual NCI device simulation driver" ); |
212 | MODULE_AUTHOR("Bongsu Jeon <bongsu.jeon@samsung.com>" ); |
213 | |