1 files changed, 136 insertions, 4 deletions

diff --git a/net/nfc/core.c b/net/nfc/core.c
index 32a7b61..3192c3f 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -33,6 +33,8 @@
 
 #define VERSION "0.1"
 
+#define NFC_CHECK_PRES_FREQ_MS	2000
+
 int nfc_devlist_generation;
 DEFINE_MUTEX(nfc_devlist_mutex);
 
@@ -95,7 +97,7 @@ int nfc_dev_down(struct nfc_dev *dev)
 		goto error;
 	}
 
-	if (dev->polling || dev->remote_activated) {
+	if (dev->polling || dev->activated_target_idx != NFC_TARGET_IDX_NONE) {
 		rc = -EBUSY;
 		goto error;
 	}
@@ -211,6 +213,8 @@ int nfc_dep_link_up(struct nfc_dev *dev, int target_index, u8 comm_mode)
 	}
 
 	rc = dev->ops->dep_link_up(dev, target_index, comm_mode, gb, gb_len);
+	if (!rc)
+		dev->activated_target_idx = target_index;
 
 error:
 	device_unlock(&dev->dev);
@@ -246,6 +250,7 @@ int nfc_dep_link_down(struct nfc_dev *dev)
 	rc = dev->ops->dep_link_down(dev);
 	if (!rc) {
 		dev->dep_link_up = false;
+		dev->activated_target_idx = NFC_TARGET_IDX_NONE;
 		nfc_llcp_mac_is_down(dev);
 		nfc_genl_dep_link_down_event(dev);
 	}
@@ -289,8 +294,13 @@ int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
 	}
 
 	rc = dev->ops->activate_target(dev, target_idx, protocol);
-	if (!rc)
-		dev->remote_activated = true;
+	if (!rc) {
+		dev->activated_target_idx = target_idx;
+
+		if (dev->ops->check_presence)
+			mod_timer(&dev->check_pres_timer, jiffies +
+				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
+	}
 
 error:
 	device_unlock(&dev->dev);
@@ -317,8 +327,11 @@ int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx)
 		goto error;
 	}
 
+	if (dev->ops->check_presence)
+		del_timer_sync(&dev->check_pres_timer);
+
 	dev->ops->deactivate_target(dev, target_idx);
-	dev->remote_activated = false;
+	dev->activated_target_idx = NFC_TARGET_IDX_NONE;
 
 error:
 	device_unlock(&dev->dev);
@@ -352,8 +365,27 @@ int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx, struct sk_buff *skb,
 		goto error;
 	}
 
+	if (dev->activated_target_idx == NFC_TARGET_IDX_NONE) {
+		rc = -ENOTCONN;
+		kfree_skb(skb);
+		goto error;
+	}
+
+	if (target_idx != dev->activated_target_idx) {
+		rc = -EADDRNOTAVAIL;
+		kfree_skb(skb);
+		goto error;
+	}
+
+	if (dev->ops->check_presence)
+		del_timer_sync(&dev->check_pres_timer);
+
 	rc = dev->ops->data_exchange(dev, target_idx, skb, cb, cb_context);
 
+	if (!rc && dev->ops->check_presence)
+		mod_timer(&dev->check_pres_timer, jiffies +
+			  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
+
 error:
 	device_unlock(&dev->dev);
 	return rc;
@@ -428,10 +460,15 @@ EXPORT_SYMBOL(nfc_alloc_recv_skb);
 int nfc_targets_found(struct nfc_dev *dev,
 		      struct nfc_target *targets, int n_targets)
 {
+	int i;
+
 	pr_debug("dev_name=%s n_targets=%d\n", dev_name(&dev->dev), n_targets);
 
 	dev->polling = false;
 
+	for (i = 0; i < n_targets; i++)
+		targets[i].idx = dev->target_next_idx++;
+
 	spin_lock_bh(&dev->targets_lock);
 
 	dev->targets_generation++;
@@ -455,17 +492,92 @@ int nfc_targets_found(struct nfc_dev *dev,
 }
 EXPORT_SYMBOL(nfc_targets_found);
 
+int nfc_target_lost(struct nfc_dev *dev, u32 target_idx)
+{
+	struct nfc_target *tg;
+	int i;
+
+	pr_debug("dev_name %s n_target %d\n", dev_name(&dev->dev), target_idx);
+
+	spin_lock_bh(&dev->targets_lock);
+
+	for (i = 0; i < dev->n_targets; i++) {
+		tg = &dev->targets[i];
+		if (tg->idx == target_idx)
+			break;
+	}
+
+	if (i == dev->n_targets) {
+		spin_unlock_bh(&dev->targets_lock);
+		return -EINVAL;
+	}
+
+	dev->targets_generation++;
+	dev->n_targets--;
+	dev->activated_target_idx = NFC_TARGET_IDX_NONE;
+
+	if (dev->n_targets) {
+		memcpy(&dev->targets[i], &dev->targets[i + 1],
+		       (dev->n_targets - i) * sizeof(struct nfc_target));
+	} else {
+		kfree(dev->targets);
+		dev->targets = NULL;
+	}
+
+	spin_unlock_bh(&dev->targets_lock);
+
+	nfc_genl_target_lost(dev, target_idx);
+
+	return 0;
+}
+EXPORT_SYMBOL(nfc_target_lost);
+
 static void nfc_release(struct device *d)
 {
 	struct nfc_dev *dev = to_nfc_dev(d);
 
 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 
+	if (dev->ops->check_presence) {
+		del_timer_sync(&dev->check_pres_timer);
+		destroy_workqueue(dev->check_pres_wq);
+	}
+
 	nfc_genl_data_exit(&dev->genl_data);
 	kfree(dev->targets);
 	kfree(dev);
 }
 
+static void nfc_check_pres_work(struct work_struct *work)
+{
+	struct nfc_dev *dev = container_of(work, struct nfc_dev,
+					   check_pres_work);
+	int rc;
+
+	device_lock(&dev->dev);
+
+	if (dev->activated_target_idx != NFC_TARGET_IDX_NONE &&
+	    timer_pending(&dev->check_pres_timer) == 0) {
+		rc = dev->ops->check_presence(dev, dev->activated_target_idx);
+		if (!rc) {
+			mod_timer(&dev->check_pres_timer, jiffies +
+				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
+		} else {
+			nfc_target_lost(dev, dev->activated_target_idx);
+			dev->activated_target_idx = NFC_TARGET_IDX_NONE;
+		}
+	}
+
+	device_unlock(&dev->dev);
+}
+
+static void nfc_check_pres_timeout(unsigned long data)
+{
+	struct nfc_dev *dev = (struct nfc_dev *)data;
+
+	queue_work(dev->check_pres_wq, &dev->check_pres_work);
+}
+
 struct class nfc_class = {
 	.name = "nfc",
 	.dev_release = nfc_release,
@@ -531,6 +643,26 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
 	/* first generation must not be 0 */
 	dev->targets_generation = 1;
 
+	dev->activated_target_idx = NFC_TARGET_IDX_NONE;
+
+	if (ops->check_presence) {
+		char name[32];
+		init_timer(&dev->check_pres_timer);
+		dev->check_pres_timer.data = (unsigned long)dev;
+		dev->check_pres_timer.function = nfc_check_pres_timeout;
+
+		INIT_WORK(&dev->check_pres_work, nfc_check_pres_work);
+		snprintf(name, sizeof(name), "nfc%d_check_pres_wq", dev->idx);
+		dev->check_pres_wq = alloc_workqueue(name, WQ_NON_REENTRANT |
+						     WQ_UNBOUND |
+						     WQ_MEM_RECLAIM, 1);
+		if (dev->check_pres_wq == NULL) {
+			kfree(dev);
+			return NULL;
+		}
+	}
+
+
 	return dev;
 }
 EXPORT_SYMBOL(nfc_allocate_device);