// SPDX-License-Identifier: GPL-2.0-or-later/* * Virtual NCI device simulation driver * * Copyright (C) 2020 Samsung Electronics * Bongsu Jeon <bongsu.jeon@samsung.com> */ #include <linux/kernel.h>#include <linux/module.h>#include <linux/miscdevice.h>#include <linux/mutex.h>#include <linux/wait.h>#include <net/nfc/nci_core.h> #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) struct virtual_nci_dev {	struct nci_dev *ndev;	struct mutex mtx;	struct sk_buff *send_buff;	struct wait_queue_head wq;	bool running;}; static int virtual_nci_open(struct nci_dev *ndev){	struct virtual_nci_dev *vdev = nci_get_drvdata(ndev); 	vdev->running = true;	return 0;} static int virtual_nci_close(struct nci_dev *ndev){	struct virtual_nci_dev *vdev = nci_get_drvdata(ndev); 	mutex_lock(&vdev->mtx);	kfree_skb(vdev->send_buff);	vdev->send_buff = NULL;	vdev->running = false;	mutex_unlock(&vdev->mtx); 	return 0;} static int virtual_nci_send(struct nci_dev *ndev, struct sk_buff *skb){	struct virtual_nci_dev *vdev = nci_get_drvdata(ndev); 	mutex_lock(&vdev->mtx);	if (vdev->send_buff || !vdev->running) {		mutex_unlock(&vdev->mtx);		kfree_skb(skb);		return -1;	}	vdev->send_buff = skb_copy(skb, GFP_KERNEL);	if (!vdev->send_buff) {		mutex_unlock(&vdev->mtx);		kfree_skb(skb);		return -1;	}	mutex_unlock(&vdev->mtx);	wake_up_interruptible(&vdev->wq);	consume_skb(skb); 	return 0;} static const 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){	struct virtual_nci_dev *vdev = file->private_data;	size_t actual_len; 	mutex_lock(&vdev->mtx);	while (!vdev->send_buff) {		mutex_unlock(&vdev->mtx);		if (wait_event_interruptible(vdev->wq, vdev->send_buff))			return -EFAULT;		mutex_lock(&vdev->mtx);	} 	actual_len = min_t(size_t, count, vdev->send_buff->len); 	if (copy_to_user(buf, vdev->send_buff->data, actual_len)) {		mutex_unlock(&vdev->mtx);		return -EFAULT;	} 	skb_pull(vdev->send_buff, actual_len);	if (vdev->send_buff->len == 0) {		consume_skb(vdev->send_buff);		vdev->send_buff = NULL;	}	mutex_unlock(&vdev->mtx); 	return actual_len;} static ssize_t virtual_ncidev_write(struct file *file,				    const char __user *buf,				    size_t count, loff_t *ppos){	struct virtual_nci_dev *vdev = file->private_data;	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(vdev->ndev, skb);	return count;} static int virtual_ncidev_open(struct inode *inode, struct file *file){	int ret = 0;	struct virtual_nci_dev *vdev; 	vdev = kzalloc_obj(*vdev);	if (!vdev)		return -ENOMEM;	vdev->ndev = nci_allocate_device(&virtual_nci_ops,		VIRTUAL_NFC_PROTOCOLS, 0, 0);	if (!vdev->ndev) {		kfree(vdev);		return -ENOMEM;	} 	mutex_init(&vdev->mtx);	init_waitqueue_head(&vdev->wq);	file->private_data = vdev;	nci_set_drvdata(vdev->ndev, vdev); 	ret = nci_register_device(vdev->ndev);	if (ret < 0) {		nci_free_device(vdev->ndev);		mutex_destroy(&vdev->mtx);		kfree(vdev);		return ret;	} 	return 0;} static int virtual_ncidev_close(struct inode *inode, struct file *file){	struct virtual_nci_dev *vdev = file->private_data; 	nci_unregister_device(vdev->ndev);	nci_free_device(vdev->ndev);	mutex_destroy(&vdev->mtx);	kfree(vdev); 	return 0;} static long virtual_ncidev_ioctl(struct file *file, unsigned int cmd,				 unsigned long arg){	struct virtual_nci_dev *vdev = file->private_data;	const struct nfc_dev *nfc_dev = vdev->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 struct miscdevice miscdev = {	.minor = MISC_DYNAMIC_MINOR,	.name = "virtual_nci",	.fops = &virtual_ncidev_fops,	.mode = 0600,}; module_misc_device(miscdev); MODULE_LICENSE("GPL");MODULE_DESCRIPTION("Virtual NCI device simulation driver");MODULE_AUTHOR("Bongsu Jeon <bongsu.jeon@samsung.com>");