NFC: pn533: Add support for incoming fragmented frame in target mode

This code processes, for Target Mode, incoming fragmented frames.
If the MI bit is present, we start a working queue to grab and aggregate
all the parts (using TmGetData between each parts). On the last one, as
there's no more MI bit, we jump on the usual behavior.

Signed-off-by: Olivier Guiter <olivier.guiter@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/nfc/pn533.c

@@ -373,6 +373,7 @@ struct pn533 {
 	struct delayed_work poll_work;
 	struct work_struct mi_rx_work;
 	struct work_struct mi_tx_work;
+	struct work_struct mi_tm_rx_work;
 	struct work_struct tg_work;
 	struct work_struct rf_work;
 
@@ -1624,27 +1625,81 @@ static struct sk_buff *pn533_alloc_poll_tg_frame(struct pn533 *dev)
 
 #define PN533_CMD_DATAEXCH_HEAD_LEN 1
 #define PN533_CMD_DATAEXCH_DATA_MAXLEN 262
+static void pn533_wq_tm_mi_recv(struct work_struct *work);
+static struct sk_buff *pn533_build_response(struct pn533 *dev);
+
 static int pn533_tm_get_data_complete(struct pn533 *dev, void *arg,
 				      struct sk_buff *resp)
 {
-	u8 status;
+	struct sk_buff *skb;
+	u8 status, ret, mi;
+	int rc;
 
 	dev_dbg(&dev->interface->dev, "%s\n", __func__);
 
-	if (IS_ERR(resp))
+	if (IS_ERR(resp)) {
+		skb_queue_purge(&dev->resp_q);
 		return PTR_ERR(resp);
+	}
 
 	status = resp->data[0];
+
+	ret = status & PN533_CMD_RET_MASK;
+	mi = status & PN533_CMD_MI_MASK;
+
 	skb_pull(resp, sizeof(status));
 
-	if (status != 0) {
-		nfc_tm_deactivated(dev->nfc_dev);
-		dev->tgt_mode = 0;
-		dev_kfree_skb(resp);
-		return 0;
+	if (ret != PN533_CMD_RET_SUCCESS) {
+		rc = -EIO;
+		goto error;
+	}
+
+	skb_queue_tail(&dev->resp_q, resp);
+
+	if (mi) {
+		queue_work(dev->wq, &dev->mi_tm_rx_work);
+		return -EINPROGRESS;
+	}
+
+	skb = pn533_build_response(dev);
+	if (!skb) {
+		rc = -EIO;
+		goto error;
 	}
 
-	return nfc_tm_data_received(dev->nfc_dev, resp);
+	return nfc_tm_data_received(dev->nfc_dev, skb);
+
+error:
+	nfc_tm_deactivated(dev->nfc_dev);
+	dev->tgt_mode = 0;
+	skb_queue_purge(&dev->resp_q);
+	dev_kfree_skb(resp);
+
+	return rc;
+}
+
+static void pn533_wq_tm_mi_recv(struct work_struct *work)
+{
+	struct pn533 *dev = container_of(work, struct pn533, mi_tm_rx_work);
+	struct sk_buff *skb;
+	int rc;
+
+	dev_dbg(&dev->interface->dev, "%s\n", __func__);
+
+	skb = pn533_alloc_skb(dev, 0);
+	if (!skb)
+		return;
+
+	rc = pn533_send_cmd_direct_async(dev,
+					PN533_CMD_TG_GET_DATA,
+					skb,
+					pn533_tm_get_data_complete,
+					NULL);
+
+	if (rc < 0)
+		dev_kfree_skb(skb);
+
+	return;
 }
 
 static void pn533_wq_tg_get_data(struct work_struct *work)
@@ -3055,6 +3110,7 @@ static int pn533_probe(struct usb_interface *interface,
 	INIT_WORK(&dev->mi_rx_work, pn533_wq_mi_recv);
 	INIT_WORK(&dev->mi_tx_work, pn533_wq_mi_send);
 	INIT_WORK(&dev->tg_work, pn533_wq_tg_get_data);
+	INIT_WORK(&dev->mi_tm_rx_work, pn533_wq_tm_mi_recv);
 	INIT_DELAYED_WORK(&dev->poll_work, pn533_wq_poll);
 	INIT_WORK(&dev->rf_work, pn533_wq_rf);
 	dev->wq = alloc_ordered_workqueue("pn533", 0);