1 files changed, 541 insertions, 0 deletions
diff --git a/drivers/nfc/nfcsim.c b/drivers/nfc/nfcsim.c
new file mode 100644
index 000000000000..c5c30fb1d7bf
--- /dev/null
+++ b/drivers/nfc/nfcsim.c
@@ -0,0 +1,541 @@
+/*
+ * 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_dev_err(&_dev->nfc_dev->dev, \
+						"%s: " fmt, __func__, ## args)
+
+#define DEV_DBG(_dev, fmt, args...) nfc_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;
+
+struct workqueue_struct *wq;
+
+static void nfcsim_cleanup_dev(struct nfcsim *dev, u8 shutdown)
+{
+	DEV_DBG(dev, "shutdown=%d", 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, "");
+
+	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, "");
+
+	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, "");
+
+	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");
+
+		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");
+		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, "");
+
+	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");
+		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");
+		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", 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");
+
+	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, "");
+
+	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, "");
+}
+
+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");
+			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");
+		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");
+		goto unlock;
+	}
+
+	DEV_DBG(dev, "Polling as %s",
+		dev->curr_polling_mode == NFCSIM_POLL_INITIATOR ?
+		"initiator" : "target");
+
+	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);
+}
+
+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;
+}
+
+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");