NFC: nfcsim: Make use of the Digital layer
authorThierry Escande <thierry.escande@collabora.com>
Thu, 23 Jun 2016 09:20:26 +0000 (11:20 +0200)
committerSamuel Ortiz <sameo@linux.intel.com>
Mon, 4 Jul 2016 10:36:30 +0000 (12:36 +0200)
With this complete rewrite, the loopback nfcsim driver now relies on the
Digital layer of the nfc stack. As with the previous version, 2 nfc
devices are declared when the driver is initialized. The driver supports
the NFC_DEP protocol in NFC-A and NFC-F technologies.

The 2 devices are using a pair of virtual links for sk_buff exchange.
The out-link of one device is the in-link of the other and conversely.

To receive data, a device calls nfcsim_link_recv_skb() on its in-link
and waits for incoming data on a wait queue. To send data, a device
calls nfcsim_link_send_skb() on its out-link which stores the passed skb
and signals its wait queue. If the peer device was in the
nfcsim_link_recv_skb() call, it will be signaled and will be able to
pass the received sk_buff up to the Digital layer.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
drivers/nfc/nfcsim.c

index 93aaca5868580dc2430b4dfdac10c937ce703721..40b4846509f419be81a5fe01a8785729d08f9f67 100644 (file)
 #include <linux/module.h>
 #include <linux/nfc.h>
 #include <net/nfc/nfc.h>
+#include <net/nfc/digital.h>
 
-#define DEV_ERR(_dev, fmt, args...) nfc_err(&_dev->nfc_dev->dev, \
-                                               "%s: " fmt, __func__, ## args)
+#define NFCSIM_ERR(d, fmt, args...) nfc_err(&d->nfc_digital_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_DBG(d, fmt, args...) dev_dbg(&d->nfc_digital_dev->nfc_dev->dev, \
+                                           "%s: " fmt, __func__, ## args)
 
-#define NFCSIM_VERSION "0.1"
+#define NFCSIM_VERSION "0.2"
 
-#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)
+#define NFCSIM_MODE_NONE       0
+#define NFCSIM_MODE_INITIATOR  1
+#define NFCSIM_MODE_TARGET     2
 
-#define RX_DEFAULT_DELAY       5
+#define NFCSIM_CAPABILITIES (NFC_DIGITAL_DRV_CAPS_IN_CRC   | \
+                            NFC_DIGITAL_DRV_CAPS_TG_CRC)
 
 struct nfcsim {
-       struct nfc_dev *nfc_dev;
+       struct nfc_digital_dev *nfc_digital_dev;
 
-       struct mutex lock;
-
-       struct delayed_work recv_work;
+       struct work_struct recv_work;
+       struct delayed_work send_work;
 
-       struct sk_buff *clone_skb;
+       struct nfcsim_link *link_in;
+       struct nfcsim_link *link_out;
 
-       struct delayed_work poll_work;
-       u8 polling_mode;
-       u8 curr_polling_mode;
+       bool up;
+       u8 mode;
+       u8 rf_tech;
 
-       u8 shutting_down;
+       u16 recv_timeout;
 
-       u8 up;
+       nfc_digital_cmd_complete_t cb;
+       void *arg;
+};
 
-       u8 initiator;
+struct nfcsim_link {
+       struct mutex lock;
 
-       u32 rx_delay;
+       u8 rf_tech;
+       u8 mode;
 
-       data_exchange_cb_t cb;
-       void *cb_context;
+       u8 shutdown;
 
-       struct nfcsim *peer_dev;
+       struct sk_buff *skb;
+       wait_queue_head_t recv_wait;
+       u8 cond;
 };
 
-static struct nfcsim *dev0;
-static struct nfcsim *dev1;
-
-static struct workqueue_struct *wq;
-
-static void nfcsim_cleanup_dev(struct nfcsim *dev, u8 shutdown)
+static struct nfcsim_link *nfcsim_link_new(void)
 {
-       DEV_DBG(dev, "shutdown=%d\n", shutdown);
-
-       mutex_lock(&dev->lock);
+       struct nfcsim_link *link;
 
-       dev->polling_mode = NFCSIM_POLL_NONE;
-       dev->shutting_down = shutdown;
-       dev->cb = NULL;
-       dev_kfree_skb(dev->clone_skb);
-       dev->clone_skb = NULL;
+       link = kzalloc(sizeof(struct nfcsim_link), GFP_KERNEL);
+       if (!link)
+               return NULL;
 
-       mutex_unlock(&dev->lock);
+       mutex_init(&link->lock);
+       init_waitqueue_head(&link->recv_wait);
 
-       cancel_delayed_work_sync(&dev->poll_work);
-       cancel_delayed_work_sync(&dev->recv_work);
+       return link;
 }
 
-static int nfcsim_target_found(struct nfcsim *dev)
+static void nfcsim_link_free(struct nfcsim_link *link)
 {
-       struct nfc_target nfc_tgt;
+       dev_kfree_skb(link->skb);
+       kfree(link);
+}
 
-       DEV_DBG(dev, "\n");
+static void nfcsim_link_recv_wake(struct nfcsim_link *link)
+{
+       link->cond = 1;
+       wake_up_interruptible(&link->recv_wait);
+}
 
-       memset(&nfc_tgt, 0, sizeof(struct nfc_target));
+static void nfcsim_link_set_skb(struct nfcsim_link *link, struct sk_buff *skb,
+                               u8 rf_tech, u8 mode)
+{
+       mutex_lock(&link->lock);
 
-       nfc_tgt.supported_protocols = NFC_PROTO_NFC_DEP_MASK;
-       nfc_targets_found(dev->nfc_dev, &nfc_tgt, 1);
+       dev_kfree_skb(link->skb);
+       link->skb = skb;
+       link->rf_tech = rf_tech;
+       link->mode = mode;
 
-       return 0;
+       mutex_unlock(&link->lock);
 }
 
-static int nfcsim_dev_up(struct nfc_dev *nfc_dev)
+static void nfcsim_link_recv_cancel(struct nfcsim_link *link)
 {
-       struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+       mutex_lock(&link->lock);
 
-       DEV_DBG(dev, "\n");
+       link->mode = NFCSIM_MODE_NONE;
 
-       mutex_lock(&dev->lock);
+       mutex_unlock(&link->lock);
 
-       dev->up = 1;
-
-       mutex_unlock(&dev->lock);
-
-       return 0;
+       nfcsim_link_recv_wake(link);
 }
 
-static int nfcsim_dev_down(struct nfc_dev *nfc_dev)
+static void nfcsim_link_shutdown(struct nfcsim_link *link)
 {
-       struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
-
-       DEV_DBG(dev, "\n");
+       mutex_lock(&link->lock);
 
-       mutex_lock(&dev->lock);
+       link->shutdown = 1;
+       link->mode = NFCSIM_MODE_NONE;
 
-       dev->up = 0;
+       mutex_unlock(&link->lock);
 
-       mutex_unlock(&dev->lock);
-
-       return 0;
+       nfcsim_link_recv_wake(link);
 }
 
-static int nfcsim_dep_link_up(struct nfc_dev *nfc_dev,
-                             struct nfc_target *target,
-                             u8 comm_mode, u8 *gb, size_t gb_len)
+static struct sk_buff *nfcsim_link_recv_skb(struct nfcsim_link *link,
+                                           int timeout, u8 rf_tech, u8 mode)
 {
        int rc;
-       struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
-       struct nfcsim *peer = dev->peer_dev;
-       u8 *remote_gb;
-       size_t remote_gb_len;
+       struct sk_buff *skb;
 
-       DEV_DBG(dev, "target_idx: %d, comm_mode: %d\n", target->idx, comm_mode);
+       rc = wait_event_interruptible_timeout(link->recv_wait,
+                                             link->cond,
+                                             msecs_to_jiffies(timeout));
 
-       mutex_lock(&peer->lock);
+       mutex_lock(&link->lock);
 
-       nfc_tm_activated(peer->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
-                        NFC_COMM_ACTIVE, gb, gb_len);
+       skb = link->skb;
+       link->skb = NULL;
 
-       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");
+       if (!rc) {
+               rc = -ETIMEDOUT;
+               goto done;
+       }
 
-               mutex_unlock(&peer->lock);
-               return -EINVAL;
+       if (!skb || link->rf_tech != rf_tech || link->mode == mode) {
+               rc = -EINVAL;
+               goto done;
        }
 
-       mutex_unlock(&peer->lock);
+       if (link->shutdown) {
+               rc = -ENODEV;
+               goto done;
+       }
 
-       mutex_lock(&dev->lock);
+done:
+       mutex_unlock(&link->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;
+       if (rc < 0) {
+               dev_kfree_skb(skb);
+               skb = ERR_PTR(rc);
        }
 
-       rc = nfc_dep_link_is_up(nfc_dev, target->idx, NFC_COMM_ACTIVE,
-                               NFC_RF_INITIATOR);
-
-       mutex_unlock(&dev->lock);
+       link->cond = 0;
 
-       return rc;
+       return skb;
 }
 
-static int nfcsim_dep_link_down(struct nfc_dev *nfc_dev)
+static void nfcsim_send_wq(struct work_struct *work)
 {
-       struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+       struct nfcsim *dev = container_of(work, struct nfcsim, send_work.work);
 
-       DEV_DBG(dev, "\n");
-
-       nfcsim_cleanup_dev(dev, 0);
-
-       return 0;
+       /*
+        * To effectively send data, the device just wake up its link_out which
+        * is the link_in of the peer device. The exchanged skb has already been
+        * stored in the dev->link_out through nfcsim_link_set_skb().
+        */
+       nfcsim_link_recv_wake(dev->link_out);
 }
 
-static int nfcsim_start_poll(struct nfc_dev *nfc_dev,
-                            u32 im_protocols, u32 tm_protocols)
+static void nfcsim_recv_wq(struct work_struct *work)
 {
-       struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
-       int rc;
-
-       mutex_lock(&dev->lock);
+       struct nfcsim *dev = container_of(work, struct nfcsim, recv_work);
+       struct sk_buff *skb;
 
-       if (dev->polling_mode != NFCSIM_POLL_NONE) {
-               DEV_ERR(dev, "Already in polling mode\n");
-               rc = -EBUSY;
-               goto exit;
-       }
+       skb = nfcsim_link_recv_skb(dev->link_in, dev->recv_timeout,
+                                  dev->rf_tech, dev->mode);
 
-       if (im_protocols & NFC_PROTO_NFC_DEP_MASK)
-               dev->polling_mode |= NFCSIM_POLL_INITIATOR;
+       if (!dev->up) {
+               NFCSIM_ERR(dev, "Device is down\n");
 
-       if (tm_protocols & NFC_PROTO_NFC_DEP_MASK)
-               dev->polling_mode |= NFCSIM_POLL_TARGET;
+               if (!IS_ERR(skb))
+                       dev_kfree_skb(skb);
 
-       if (dev->polling_mode == NFCSIM_POLL_NONE) {
-               DEV_ERR(dev, "Unsupported polling mode\n");
-               rc = -EINVAL;
-               goto exit;
+               skb = ERR_PTR(-ENODEV);
        }
 
-       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;
+       dev->cb(dev->nfc_digital_dev, dev->arg, skb);
 }
 
-static void nfcsim_stop_poll(struct nfc_dev *nfc_dev)
+static int nfcsim_send(struct nfc_digital_dev *ddev, struct sk_buff *skb,
+                      u16 timeout, nfc_digital_cmd_complete_t cb, void *arg)
 {
-       struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+       struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
+       u8 delay;
 
-       DEV_DBG(dev, "Stop poll\n");
+       if (!dev->up) {
+               NFCSIM_ERR(dev, "Device is down\n");
+               return -ENODEV;
+       }
+
+       dev->recv_timeout = timeout;
+       dev->cb = cb;
+       dev->arg = arg;
 
-       mutex_lock(&dev->lock);
+       schedule_work(&dev->recv_work);
 
-       dev->polling_mode = NFCSIM_POLL_NONE;
+       if (skb) {
+               nfcsim_link_set_skb(dev->link_out, skb, dev->rf_tech,
+                                   dev->mode);
 
-       mutex_unlock(&dev->lock);
+               /* Add random delay (between 3 and 10 ms) before sending data */
+               get_random_bytes(&delay, 1);
+               delay = 3 + (delay & 0x07);
 
-       cancel_delayed_work_sync(&dev->poll_work);
+               schedule_delayed_work(&dev->send_work, msecs_to_jiffies(delay));
+       }
+
+       return 0;
 }
 
-static int nfcsim_activate_target(struct nfc_dev *nfc_dev,
-                                 struct nfc_target *target, u32 protocol)
+static void nfcsim_abort_cmd(struct nfc_digital_dev *ddev)
 {
-       struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
-
-       DEV_DBG(dev, "\n");
+       struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
 
-       return -ENOTSUPP;
+       nfcsim_link_recv_cancel(dev->link_in);
 }
 
-static void nfcsim_deactivate_target(struct nfc_dev *nfc_dev,
-                                    struct nfc_target *target, u8 mode)
+static int nfcsim_switch_rf(struct nfc_digital_dev *ddev, bool on)
 {
-       struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
+       struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
 
-       DEV_DBG(dev, "\n");
+       dev->up = on;
+
+       return 0;
 }
 
-static void nfcsim_wq_recv(struct work_struct *work)
+static int nfcsim_in_configure_hw(struct nfc_digital_dev *ddev,
+                                         int type, int param)
 {
-       struct nfcsim *dev = container_of(work, struct nfcsim,
-                                         recv_work.work);
+       struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
 
-       mutex_lock(&dev->lock);
+       switch (type) {
+       case NFC_DIGITAL_CONFIG_RF_TECH:
+               dev->up = true;
+               dev->mode = NFCSIM_MODE_INITIATOR;
+               dev->rf_tech = param;
+               break;
 
-       if (dev->shutting_down || !dev->up || !dev->clone_skb) {
-               dev_kfree_skb(dev->clone_skb);
-               goto exit;
-       }
+       case NFC_DIGITAL_CONFIG_FRAMING:
+               break;
 
-       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);
+       default:
+               NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
+               return -EINVAL;
        }
 
-exit:
-       dev->clone_skb = NULL;
-
-       mutex_unlock(&dev->lock);
+       return 0;
 }
 
-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)
+static int nfcsim_in_send_cmd(struct nfc_digital_dev *ddev,
+                              struct sk_buff *skb, u16 timeout,
+                              nfc_digital_cmd_complete_t cb, void *arg)
 {
-       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;
+       return nfcsim_send(ddev, skb, timeout, cb, arg);
+}
 
-       mutex_unlock(&dev->lock);
+static int nfcsim_tg_configure_hw(struct nfc_digital_dev *ddev,
+                                         int type, int param)
+{
+       struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
 
-       mutex_lock(&peer->lock);
+       switch (type) {
+       case NFC_DIGITAL_CONFIG_RF_TECH:
+               dev->up = true;
+               dev->mode = NFCSIM_MODE_TARGET;
+               dev->rf_tech = param;
+               break;
 
-       peer->clone_skb = skb_clone(skb, GFP_KERNEL);
+       case NFC_DIGITAL_CONFIG_FRAMING:
+               break;
 
-       if (!peer->clone_skb) {
-               DEV_ERR(dev, "skb_clone failed\n");
-               mutex_unlock(&peer->lock);
-               err = -ENOMEM;
-               goto exit;
+       default:
+               NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
+               return -EINVAL;
        }
 
-       /* 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.
-        */
-       queue_delayed_work(wq, &peer->recv_work,
-                       msecs_to_jiffies(dev->rx_delay));
-
-       mutex_unlock(&peer->lock);
-
-       err = 0;
-exit:
-       dev_kfree_skb(skb);
-
-       return err;
+       return 0;
 }
 
-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)
+static int nfcsim_tg_send_cmd(struct nfc_digital_dev *ddev,
+                              struct sk_buff *skb, u16 timeout,
+                              nfc_digital_cmd_complete_t cb, void *arg)
 {
-       return nfcsim_tx(nfc_dev, target, skb, cb, cb_context);
+       return nfcsim_send(ddev, skb, timeout, cb, arg);
 }
 
-static int nfcsim_tm_send(struct nfc_dev *nfc_dev, struct sk_buff *skb)
+static int nfcsim_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
+                           nfc_digital_cmd_complete_t cb, void *arg)
 {
-       return nfcsim_tx(nfc_dev, NULL, skb, NULL, NULL);
+       return nfcsim_send(ddev, NULL, timeout, cb, arg);
 }
 
-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;
-       }
+static struct nfc_digital_ops nfcsim_digital_ops = {
+       .in_configure_hw = nfcsim_in_configure_hw,
+       .in_send_cmd = nfcsim_in_send_cmd,
 
-       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;
+       .tg_listen = nfcsim_tg_listen,
+       .tg_configure_hw = nfcsim_tg_configure_hw,
+       .tg_send_cmd = nfcsim_tg_send_cmd,
 
-               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;
-       }
-}
+       .abort_cmd = nfcsim_abort_cmd,
+       .switch_rf = nfcsim_switch_rf,
+};
 
-static void nfcsim_wq_poll(struct work_struct *work)
+static struct nfcsim *nfcsim_device_new(struct nfcsim_link *link_in,
+                                       struct nfcsim_link *link_out)
 {
-       struct nfcsim *dev = container_of(work, struct nfcsim, poll_work.work);
-       struct nfcsim *peer = dev->peer_dev;
+       struct nfcsim *dev;
+       int rc;
 
-       /* 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);
+       dev = kzalloc(sizeof(struct nfcsim), GFP_KERNEL);
+       if (!dev)
+               return ERR_PTR(-ENOMEM);
 
-       nfcsim_set_polling_mode(dev);
+       INIT_DELAYED_WORK(&dev->send_work, nfcsim_send_wq);
+       INIT_WORK(&dev->recv_work, nfcsim_recv_wq);
 
-       if (dev->curr_polling_mode == NFCSIM_POLL_NONE) {
-               DEV_DBG(dev, "Not polling\n");
-               goto unlock;
+       dev->nfc_digital_dev =
+                       nfc_digital_allocate_device(&nfcsim_digital_ops,
+                                                   NFC_PROTO_NFC_DEP_MASK,
+                                                   NFCSIM_CAPABILITIES,
+                                                   0, 0);
+       if (!dev->nfc_digital_dev) {
+               kfree(dev);
+               return ERR_PTR(-ENOMEM);
        }
 
-       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;
+       nfc_digital_set_drvdata(dev->nfc_digital_dev, dev);
 
-       if (peer->curr_polling_mode == NFCSIM_POLL_TARGET) {
-               peer->polling_mode = NFCSIM_POLL_NONE;
-               dev->polling_mode = NFCSIM_POLL_NONE;
+       dev->link_in = link_in;
+       dev->link_out = link_out;
 
-               dev->initiator = 1;
-
-               nfcsim_target_found(dev);
+       rc = nfc_digital_register_device(dev->nfc_digital_dev);
+       if (rc) {
+               pr_err("Could not register digital device (%d)\n", rc);
+               nfc_digital_free_device(dev->nfc_digital_dev);
+               kfree(dev);
 
-               goto unlock;
+               return ERR_PTR(rc);
        }
 
-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);
+       return dev;
 }
 
-static struct nfcsim *nfcsim_init_dev(void)
+static void nfcsim_device_free(struct nfcsim *dev)
 {
-       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_digital_unregister_device(dev->nfc_digital_dev);
 
-       nfc_set_drvdata(dev->nfc_dev, dev);
+       dev->up = false;
 
-       rc = nfc_register_device(dev->nfc_dev);
-       if (rc)
-               goto free_nfc_dev;
+       nfcsim_link_shutdown(dev->link_in);
 
-       dev->rx_delay = RX_DEFAULT_DELAY;
-       return dev;
+       cancel_delayed_work_sync(&dev->send_work);
+       cancel_work_sync(&dev->recv_work);
 
-free_nfc_dev:
-       nfc_free_device(dev->nfc_dev);
+       nfc_digital_free_device(dev->nfc_digital_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 struct nfcsim *dev0;
+static struct nfcsim *dev1;
 
 static int __init nfcsim_init(void)
 {
+       struct nfcsim_link *link0, *link1;
        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) {
+       link0 = nfcsim_link_new();
+       link1 = nfcsim_link_new();
+       if (!link0 || !link1) {
                rc = -ENOMEM;
-               goto exit;
+               goto exit_err;
        }
 
-       dev0 = nfcsim_init_dev();
+       dev0 = nfcsim_device_new(link0, link1);
        if (IS_ERR(dev0)) {
                rc = PTR_ERR(dev0);
-               goto exit;
+               goto exit_err;
        }
 
-       dev1 = nfcsim_init_dev();
+       dev1 = nfcsim_device_new(link1, link0);
        if (IS_ERR(dev1)) {
-               kfree(dev0);
+               nfcsim_device_free(dev0);
 
                rc = PTR_ERR(dev1);
-               goto exit;
+               goto exit_err;
        }
 
-       dev0->peer_dev = dev1;
-       dev1->peer_dev = dev0;
+       pr_info("nfcsim " NFCSIM_VERSION " initialized\n");
 
-       pr_debug("NFCsim " NFCSIM_VERSION " initialized\n");
+       return 0;
+
+exit_err:
+       pr_err("Failed to initialize nfcsim driver (%d)\n", rc);
 
-       rc = 0;
-exit:
-       if (rc)
-               pr_err("Failed to initialize nfcsim driver (%d)\n",
-                      rc);
+       nfcsim_link_free(link0);
+       nfcsim_link_free(link1);
 
        return rc;
 }
 
 static void __exit nfcsim_exit(void)
 {
-       nfcsim_cleanup_dev(dev0, 1);
-       nfcsim_cleanup_dev(dev1, 1);
+       struct nfcsim_link *link0, *link1;
+
+       link0 = dev0->link_in;
+       link1 = dev0->link_out;
 
-       nfcsim_free_device(dev0);
-       nfcsim_free_device(dev1);
+       nfcsim_device_free(dev0);
+       nfcsim_device_free(dev1);
 
-       destroy_workqueue(wq);
+       nfcsim_link_free(link0);
+       nfcsim_link_free(link1);
 }
 
 module_init(nfcsim_init);