--- /dev/null
+/*
+ * NFC hardware simulation driver
+ * Copyright (c) 2013, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/nfc.h>
+#include <net/nfc/nfc.h>
+
+#define DEV_ERR(_dev, fmt, args...) nfc_err(&_dev->nfc_dev->dev, \
+ "%s: " fmt, __func__, ## args)
+
+#define DEV_DBG(_dev, fmt, args...) dev_dbg(&_dev->nfc_dev->dev, \
+ "%s: " fmt, __func__, ## args)
+
+#define NFCSIM_VERSION "0.1"
+
+#define NFCSIM_POLL_NONE 0
+#define NFCSIM_POLL_INITIATOR 1
+#define NFCSIM_POLL_TARGET 2
+#define NFCSIM_POLL_DUAL (NFCSIM_POLL_INITIATOR | NFCSIM_POLL_TARGET)
+
+struct nfcsim {
+ struct nfc_dev *nfc_dev;
+
+ struct mutex lock;
+
+ struct delayed_work recv_work;
+
+ struct sk_buff *clone_skb;
+
+ struct delayed_work poll_work;
+ u8 polling_mode;
+ u8 curr_polling_mode;
+
+ u8 shutting_down;
+
+ u8 up;
+
+ u8 initiator;
+
+ data_exchange_cb_t cb;
+ void *cb_context;
+
+ struct nfcsim *peer_dev;
+};
+
+static struct nfcsim *dev0;
+static struct nfcsim *dev1;
+
+static struct workqueue_struct *wq;
+
+static void nfcsim_cleanup_dev(struct nfcsim *dev, u8 shutdown)
+{
+ DEV_DBG(dev, "shutdown=%d\n", shutdown);
+
+ mutex_lock(&dev->lock);
+
+ dev->polling_mode = NFCSIM_POLL_NONE;
+ dev->shutting_down = shutdown;
+ dev->cb = NULL;
+ dev_kfree_skb(dev->clone_skb);
+ dev->clone_skb = NULL;
+
+ mutex_unlock(&dev->lock);
+
+ cancel_delayed_work_sync(&dev->poll_work);
+ cancel_delayed_work_sync(&dev->recv_work);
+}
+
+static int nfcsim_target_found(struct nfcsim *dev)
+{
+ struct nfc_target nfc_tgt;
+
+ DEV_DBG(dev, "\n");
+
+ memset(&nfc_tgt, 0, sizeof(struct nfc_target));
+
+ nfc_tgt.supported_protocols = NFC_PROTO_NFC_DEP_MASK;
+ nfc_targets_found(dev->nfc_dev, &nfc_tgt, 1);
+
+ return 0;
+}
+
+static int nfcsim_dev_up(struct nfc_dev *nfc_dev)
+{
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+
+ DEV_DBG(dev, "\n");
+
+ mutex_lock(&dev->lock);
+
+ dev->up = 1;
+
+ mutex_unlock(&dev->lock);
+
+ return 0;
+}
+
+static int nfcsim_dev_down(struct nfc_dev *nfc_dev)
+{
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+
+ DEV_DBG(dev, "\n");
+
+ mutex_lock(&dev->lock);
+
+ dev->up = 0;
+
+ mutex_unlock(&dev->lock);
+
+ return 0;
+}
+
+static int nfcsim_dep_link_up(struct nfc_dev *nfc_dev,
+ struct nfc_target *target,
+ u8 comm_mode, u8 *gb, size_t gb_len)
+{
+ int rc;
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+ struct nfcsim *peer = dev->peer_dev;
+ u8 *remote_gb;
+ size_t remote_gb_len;
+
+ DEV_DBG(dev, "target_idx: %d, comm_mode: %d\n", target->idx, comm_mode);
+
+ mutex_lock(&peer->lock);
+
+ nfc_tm_activated(peer->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
+ NFC_COMM_ACTIVE, gb, gb_len);
+
+ remote_gb = nfc_get_local_general_bytes(peer->nfc_dev, &remote_gb_len);
+ if (!remote_gb) {
+ DEV_ERR(peer, "Can't get remote general bytes\n");
+
+ mutex_unlock(&peer->lock);
+ return -EINVAL;
+ }
+
+ mutex_unlock(&peer->lock);
+
+ mutex_lock(&dev->lock);
+
+ rc = nfc_set_remote_general_bytes(nfc_dev, remote_gb, remote_gb_len);
+ if (rc) {
+ DEV_ERR(dev, "Can't set remote general bytes\n");
+ mutex_unlock(&dev->lock);
+ return rc;
+ }
+
+ rc = nfc_dep_link_is_up(nfc_dev, target->idx, NFC_COMM_ACTIVE,
+ NFC_RF_INITIATOR);
+
+ mutex_unlock(&dev->lock);
+
+ return rc;
+}
+
+static int nfcsim_dep_link_down(struct nfc_dev *nfc_dev)
+{
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+
+ DEV_DBG(dev, "\n");
+
+ nfcsim_cleanup_dev(dev, 0);
+
+ return 0;
+}
+
+static int nfcsim_start_poll(struct nfc_dev *nfc_dev,
+ u32 im_protocols, u32 tm_protocols)
+{
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+ int rc;
+
+ mutex_lock(&dev->lock);
+
+ if (dev->polling_mode != NFCSIM_POLL_NONE) {
+ DEV_ERR(dev, "Already in polling mode\n");
+ rc = -EBUSY;
+ goto exit;
+ }
+
+ if (im_protocols & NFC_PROTO_NFC_DEP_MASK)
+ dev->polling_mode |= NFCSIM_POLL_INITIATOR;
+
+ if (tm_protocols & NFC_PROTO_NFC_DEP_MASK)
+ dev->polling_mode |= NFCSIM_POLL_TARGET;
+
+ if (dev->polling_mode == NFCSIM_POLL_NONE) {
+ DEV_ERR(dev, "Unsupported polling mode\n");
+ rc = -EINVAL;
+ goto exit;
+ }
+
+ dev->initiator = 0;
+ dev->curr_polling_mode = NFCSIM_POLL_NONE;
+
+ queue_delayed_work(wq, &dev->poll_work, 0);
+
+ DEV_DBG(dev, "Start polling: im: 0x%X, tm: 0x%X\n", im_protocols,
+ tm_protocols);
+
+ rc = 0;
+exit:
+ mutex_unlock(&dev->lock);
+
+ return rc;
+}
+
+static void nfcsim_stop_poll(struct nfc_dev *nfc_dev)
+{
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+
+ DEV_DBG(dev, "Stop poll\n");
+
+ mutex_lock(&dev->lock);
+
+ dev->polling_mode = NFCSIM_POLL_NONE;
+
+ mutex_unlock(&dev->lock);
+
+ cancel_delayed_work_sync(&dev->poll_work);
+}
+
+static int nfcsim_activate_target(struct nfc_dev *nfc_dev,
+ struct nfc_target *target, u32 protocol)
+{
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+
+ DEV_DBG(dev, "\n");
+
+ return -ENOTSUPP;
+}
+
+static void nfcsim_deactivate_target(struct nfc_dev *nfc_dev,
+ struct nfc_target *target)
+{
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+
+ DEV_DBG(dev, "\n");
+}
+
+static void nfcsim_wq_recv(struct work_struct *work)
+{
+ struct nfcsim *dev = container_of(work, struct nfcsim,
+ recv_work.work);
+
+ mutex_lock(&dev->lock);
+
+ if (dev->shutting_down || !dev->up || !dev->clone_skb) {
+ dev_kfree_skb(dev->clone_skb);
+ goto exit;
+ }
+
+ if (dev->initiator) {
+ if (!dev->cb) {
+ DEV_ERR(dev, "Null recv callback\n");
+ dev_kfree_skb(dev->clone_skb);
+ goto exit;
+ }
+
+ dev->cb(dev->cb_context, dev->clone_skb, 0);
+ dev->cb = NULL;
+ } else {
+ nfc_tm_data_received(dev->nfc_dev, dev->clone_skb);
+ }
+
+exit:
+ dev->clone_skb = NULL;
+
+ mutex_unlock(&dev->lock);
+}
+
+static int nfcsim_tx(struct nfc_dev *nfc_dev, struct nfc_target *target,
+ struct sk_buff *skb, data_exchange_cb_t cb,
+ void *cb_context)
+{
+ struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+ struct nfcsim *peer = dev->peer_dev;
+ int err;
+
+ mutex_lock(&dev->lock);
+
+ if (dev->shutting_down || !dev->up) {
+ mutex_unlock(&dev->lock);
+ err = -ENODEV;
+ goto exit;
+ }
+
+ dev->cb = cb;
+ dev->cb_context = cb_context;
+
+ mutex_unlock(&dev->lock);
+
+ mutex_lock(&peer->lock);
+
+ peer->clone_skb = skb_clone(skb, GFP_KERNEL);
+
+ if (!peer->clone_skb) {
+ DEV_ERR(dev, "skb_clone failed\n");
+ mutex_unlock(&peer->lock);
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ /* This simulates an arbitrary transmission delay between the 2 devices.
+ * If packet transmission occurs immediately between them, we have a
+ * non-stop flow of several tens of thousands SYMM packets per second
+ * and a burning cpu.
+ *
+ * TODO: Add support for a sysfs entry to control this delay.
+ */
+ queue_delayed_work(wq, &peer->recv_work, msecs_to_jiffies(5));
+
+ mutex_unlock(&peer->lock);
+
+ err = 0;
+exit:
+ dev_kfree_skb(skb);
+
+ return err;
+}
+
+static int nfcsim_im_transceive(struct nfc_dev *nfc_dev,
+ struct nfc_target *target, struct sk_buff *skb,
+ data_exchange_cb_t cb, void *cb_context)
+{
+ return nfcsim_tx(nfc_dev, target, skb, cb, cb_context);
+}
+
+static int nfcsim_tm_send(struct nfc_dev *nfc_dev, struct sk_buff *skb)
+{
+ return nfcsim_tx(nfc_dev, NULL, skb, NULL, NULL);
+}
+
+static struct nfc_ops nfcsim_nfc_ops = {
+ .dev_up = nfcsim_dev_up,
+ .dev_down = nfcsim_dev_down,
+ .dep_link_up = nfcsim_dep_link_up,
+ .dep_link_down = nfcsim_dep_link_down,
+ .start_poll = nfcsim_start_poll,
+ .stop_poll = nfcsim_stop_poll,
+ .activate_target = nfcsim_activate_target,
+ .deactivate_target = nfcsim_deactivate_target,
+ .im_transceive = nfcsim_im_transceive,
+ .tm_send = nfcsim_tm_send,
+};
+
+static void nfcsim_set_polling_mode(struct nfcsim *dev)
+{
+ if (dev->polling_mode == NFCSIM_POLL_NONE) {
+ dev->curr_polling_mode = NFCSIM_POLL_NONE;
+ return;
+ }
+
+ if (dev->curr_polling_mode == NFCSIM_POLL_NONE) {
+ if (dev->polling_mode & NFCSIM_POLL_INITIATOR)
+ dev->curr_polling_mode = NFCSIM_POLL_INITIATOR;
+ else
+ dev->curr_polling_mode = NFCSIM_POLL_TARGET;
+
+ return;
+ }
+
+ if (dev->polling_mode == NFCSIM_POLL_DUAL) {
+ if (dev->curr_polling_mode == NFCSIM_POLL_TARGET)
+ dev->curr_polling_mode = NFCSIM_POLL_INITIATOR;
+ else
+ dev->curr_polling_mode = NFCSIM_POLL_TARGET;
+ }
+}
+
+static void nfcsim_wq_poll(struct work_struct *work)
+{
+ struct nfcsim *dev = container_of(work, struct nfcsim, poll_work.work);
+ struct nfcsim *peer = dev->peer_dev;
+
+ /* These work items run on an ordered workqueue and are therefore
+ * serialized. So we can take both mutexes without being dead locked.
+ */
+ mutex_lock(&dev->lock);
+ mutex_lock(&peer->lock);
+
+ nfcsim_set_polling_mode(dev);
+
+ if (dev->curr_polling_mode == NFCSIM_POLL_NONE) {
+ DEV_DBG(dev, "Not polling\n");
+ goto unlock;
+ }
+
+ DEV_DBG(dev, "Polling as %s",
+ dev->curr_polling_mode == NFCSIM_POLL_INITIATOR ?
+ "initiator\n" : "target\n");
+
+ if (dev->curr_polling_mode == NFCSIM_POLL_TARGET)
+ goto sched_work;
+
+ if (peer->curr_polling_mode == NFCSIM_POLL_TARGET) {
+ peer->polling_mode = NFCSIM_POLL_NONE;
+ dev->polling_mode = NFCSIM_POLL_NONE;
+
+ dev->initiator = 1;
+
+ nfcsim_target_found(dev);
+
+ goto unlock;
+ }
+
+sched_work:
+ /* This defines the delay for an initiator to check if the other device
+ * is polling in target mode.
+ * If the device starts in dual mode polling, it switches between
+ * initiator and target at every round.
+ * Because the wq is ordered and only 1 work item is executed at a time,
+ * we'll always have one device polling as initiator and the other as
+ * target at some point, even if both are started in dual mode.
+ */
+ queue_delayed_work(wq, &dev->poll_work, msecs_to_jiffies(200));
+
+unlock:
+ mutex_unlock(&peer->lock);
+ mutex_unlock(&dev->lock);
+}
+
+static struct nfcsim *nfcsim_init_dev(void)
+{
+ struct nfcsim *dev;
+ int rc = -ENOMEM;
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (dev == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ mutex_init(&dev->lock);
+
+ INIT_DELAYED_WORK(&dev->recv_work, nfcsim_wq_recv);
+ INIT_DELAYED_WORK(&dev->poll_work, nfcsim_wq_poll);
+
+ dev->nfc_dev = nfc_allocate_device(&nfcsim_nfc_ops,
+ NFC_PROTO_NFC_DEP_MASK,
+ 0, 0);
+ if (!dev->nfc_dev)
+ goto error;
+
+ nfc_set_drvdata(dev->nfc_dev, dev);
+
+ rc = nfc_register_device(dev->nfc_dev);
+ if (rc)
+ goto free_nfc_dev;
+
+ return dev;
+
+free_nfc_dev:
+ nfc_free_device(dev->nfc_dev);
+
+error:
+ kfree(dev);
+
+ return ERR_PTR(rc);
+}
+
+static void nfcsim_free_device(struct nfcsim *dev)
+{
+ nfc_unregister_device(dev->nfc_dev);
+
+ nfc_free_device(dev->nfc_dev);
+
+ kfree(dev);
+}
+
+static int __init nfcsim_init(void)
+{
+ int rc;
+
+ /* We need an ordered wq to ensure that poll_work items are executed
+ * one at a time.
+ */
+ wq = alloc_ordered_workqueue("nfcsim", 0);
+ if (!wq) {
+ rc = -ENOMEM;
+ goto exit;
+ }
+
+ dev0 = nfcsim_init_dev();
+ if (IS_ERR(dev0)) {
+ rc = PTR_ERR(dev0);
+ goto exit;
+ }
+
+ dev1 = nfcsim_init_dev();
+ if (IS_ERR(dev1)) {
+ kfree(dev0);
+
+ rc = PTR_ERR(dev1);
+ goto exit;
+ }
+
+ dev0->peer_dev = dev1;
+ dev1->peer_dev = dev0;
+
+ pr_debug("NFCsim " NFCSIM_VERSION " initialized\n");
+
+ rc = 0;
+exit:
+ if (rc)
+ pr_err("Failed to initialize nfcsim driver (%d)\n",
+ rc);
+
+ return rc;
+}
+
+static void __exit nfcsim_exit(void)
+{
+ nfcsim_cleanup_dev(dev0, 1);
+ nfcsim_cleanup_dev(dev1, 1);
+
+ nfcsim_free_device(dev0);
+ nfcsim_free_device(dev1);
+
+ destroy_workqueue(wq);
+}
+
+module_init(nfcsim_init);
+module_exit(nfcsim_exit);
+
+MODULE_DESCRIPTION("NFCSim driver ver " NFCSIM_VERSION);
+MODULE_VERSION(NFCSIM_VERSION);
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff