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path: root/drivers/nfc/virtual_ncidev.c
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Diffstat (limited to 'drivers/nfc/virtual_ncidev.c')
-rw-r--r--drivers/nfc/virtual_ncidev.c223
1 files changed, 223 insertions, 0 deletions
diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
new file mode 100644
index 000000000..85c06dbb2
--- /dev/null
+++ b/drivers/nfc/virtual_ncidev.c
@@ -0,0 +1,223 @@
+// 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 <linux/wait.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 DECLARE_WAIT_QUEUE_HEAD(wq);
+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);
+ kfree_skb(skb);
+ return 0;
+ }
+
+ if (send_buff) {
+ mutex_unlock(&nci_mutex);
+ kfree_skb(skb);
+ return -1;
+ }
+ send_buff = skb_copy(skb, GFP_KERNEL);
+ mutex_unlock(&nci_mutex);
+ wake_up_interruptible(&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)
+{
+ size_t actual_len;
+
+ mutex_lock(&nci_mutex);
+ while (!send_buff) {
+ mutex_unlock(&nci_mutex);
+ if (wait_event_interruptible(wq, send_buff))
+ return -EFAULT;
+ mutex_lock(&nci_mutex);
+ }
+
+ 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)
+{
+ const 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 = 0600;
+
+ 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>");