// 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 <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 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);		return 0;	} 	if (send_buff) {		mutex_unlock(&nci_mutex);		return -1;	}	send_buff = skb_copy(skb, GFP_KERNEL);	mutex_unlock(&nci_mutex); 	return 0;} static 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);	if (!send_buff) {		mutex_unlock(&nci_mutex);		return 0;	} 	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){	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 = S_IALLUGO; 	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>");