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 31 static int virtual_nci_open(struct nci_dev *ndev) 32 { 33 return 0; 34 } 35 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 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 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 } 107 108 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 } 127 128 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 } 158 159 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 } 170 171 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 static int __init virtual_ncidev_init(void) 204 { 205 return misc_register(&miscdev); 206 } 207 208 static void __exit virtual_ncidev_exit(void) 209 { 210 misc_deregister(&miscdev); 211 } 212 213 module_init(virtual_ncidev_init); 214 module_exit(virtual_ncidev_exit); 215 216 MODULE_LICENSE("GPL"); 217 MODULE_DESCRIPTION("Virtual NCI device simulation driver"); 218 MODULE_AUTHOR("Bongsu Jeon <bongsu.jeon@samsung.com>"); 219