Commit e624e6c3 authored by Bongsu Jeon's avatar Bongsu Jeon Committed by Jakub Kicinski
Browse files

nfc: Add a virtual nci device driver 



NCI virtual device simulates a NCI device to the user. It can be used to
validate the NCI module and applications. This driver supports
communication between the virtual NCI device and NCI module.

Signed-off-by: default avatarBongsu Jeon <bongsu.jeon@samsung.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 8c224751

drivers/nfc/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -49,6 +49,17 @@ config NFC_PORT100 


	  If unsure, say N.



config NFC_VIRTUAL_NCI

	tristate "NCI device simulator driver"

	depends on NFC_NCI

	help

	  NCI virtual device simulates a NCI device to the user.

	  It can be used to validate the NCI module and applications.

	  This driver supports communication between the virtual NCI device and

	  module.



	  If unsure, say N.



source "drivers/nfc/fdp/Kconfig"

source "drivers/nfc/pn544/Kconfig"

source "drivers/nfc/pn533/Kconfig"

drivers/nfc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -17,3 +17,4 @@ obj-$(CONFIG_NFC_ST_NCI) += st-nci/ 
obj-$(CONFIG_NFC_NXP_NCI)	+= nxp-nci/

obj-$(CONFIG_NFC_S3FWRN5)	+= s3fwrn5/

obj-$(CONFIG_NFC_ST95HF)	+= st95hf/

obj-$(CONFIG_NFC_VIRTUAL_NCI)	+= virtual_ncidev.o

drivers/nfc/virtual_ncidev.c

0 → 100644
+215 −0
Original line number Diff line number Diff line 
// 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>");