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Diffstat (limited to '')
| -rw-r--r-- | drivers/nfc/virtual_ncidev.c | 223 |
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>"); |