NFC: Add Core support to generate tag lost event

Some HW/drivers get notifications when a tag moves out of the radio field.
This notification is now forwarded to user space through netlink.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 71 insertions, 1 deletions

diff --git a/net/nfc/core.c b/net/nfc/core.c
index 44a701806ba..da353275fbc 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);
 
@@ -292,9 +294,14 @@ int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
         }
 
         rc = dev->ops->activate_target(dev, target_idx, protocol);
-        if (!rc)
+        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);
         return rc;
@@ -320,6 +327,9 @@ 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->activated_target_idx = NFC_TARGET_IDX_NONE;
 
@@ -367,8 +377,15 @@ int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx, struct sk_buff *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;
@@ -521,11 +538,46 @@ static void nfc_release(struct device *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,
@@ -593,6 +645,24 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
 
         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);