NFC: pn533: Add a new pn533_send_cmd_async iface

This is intendend to replace pn533_send_cmd_frame_async() which
requires from the caller to create a complete frame.

The new function constructs a frame and sends it out which hides the
frame logic and avoid code duplication.

The caller has to allocate skb and put its payload there, and finally
provide the skb together with a complete cb to pn533_send_cmd_async().

Response skb is allocated by the core part and pass to the caller cb.
Next, the caller has to free it when is not needed anymore or pass it
up to the stack.

Signed-off-by: Waldemar Rymarkiewicz <waldemar.rymarkiewicz@tieto.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/nfc/pn533.c

@@ -117,6 +117,7 @@ MODULE_DEVICE_TABLE(usb, pn533_table);
 #define PN533_CMD_TG_INIT_AS_TARGET 0x8c
 #define PN533_CMD_TG_GET_DATA 0x86
 #define PN533_CMD_TG_SET_DATA 0x8e
+#define PN533_CMD_UNDEF 0xff
 
 #define PN533_CMD_RESPONSE(cmd) (cmd + 1)
 
@@ -130,6 +131,9 @@ struct pn533;
 typedef int (*pn533_cmd_complete_t) (struct pn533 *dev, void *arg,
 					u8 *params, int params_len);
 
+typedef int (*pn533_send_async_complete_t) (struct pn533 *dev, void *arg,
+					struct sk_buff *resp);
+
 /* structs for pn533 commands */
 
 /* PN533_CMD_GET_FIRMWARE_VERSION */
@@ -390,6 +394,9 @@ struct pn533_cmd {
 	struct pn533_frame *out_frame;
 	struct pn533_frame *in_frame;
 	int in_frame_len;
+	u8 cmd_code;
+	struct sk_buff *req;
+	struct sk_buff *resp;
 	pn533_cmd_complete_t cmd_complete;
 	void *arg;
 };
@@ -678,6 +685,151 @@ static int __pn533_send_cmd_frame_async(struct pn533 *dev,
 	return rc;
 }
 
+static void pn533_build_cmd_frame(u8 cmd_code, struct sk_buff *skb)
+{
+	struct pn533_frame *frame;
+	/* payload is already there, just update datalen */
+	int payload_len = skb->len;
+
+	skb_push(skb, PN533_FRAME_HEADER_LEN);
+	skb_put(skb, PN533_FRAME_TAIL_LEN);
+
+	frame = (struct pn533_frame *)skb->data;
+
+	pn533_tx_frame_init(frame, cmd_code);
+	frame->datalen += payload_len;
+	pn533_tx_frame_finish(frame);
+}
+
+struct pn533_send_async_complete_arg {
+	pn533_send_async_complete_t  complete_cb;
+	void *complete_cb_context;
+	struct sk_buff *resp;
+	struct sk_buff *req;
+};
+
+static int pn533_send_async_complete(struct pn533 *dev, void *_arg, u8 *params,
+				     int params_len)
+{
+	struct pn533_send_async_complete_arg *arg = _arg;
+
+	struct sk_buff *req = arg->req;
+	struct sk_buff *resp = arg->resp;
+
+	struct pn533_frame *frame = (struct pn533_frame *)resp->data;
+	int rc;
+
+	dev_kfree_skb(req);
+
+	if (params_len < 0) {
+		nfc_dev_err(&dev->interface->dev,
+			    "Error %d when starting as a target",
+			    params_len);
+
+		arg->complete_cb(dev, arg->complete_cb_context,
+				 ERR_PTR(params_len));
+		rc = params_len;
+		dev_kfree_skb(resp);
+		goto out;
+	}
+
+	skb_put(resp, PN533_FRAME_SIZE(frame));
+	skb_pull(resp, PN533_FRAME_HEADER_LEN);
+	skb_trim(resp, resp->len - PN533_FRAME_TAIL_LEN);
+
+	rc = arg->complete_cb(dev, arg->complete_cb_context, resp);
+
+out:
+	kfree(arg);
+	return rc;
+}
+
+static int __pn533_send_async(struct pn533 *dev, u8 cmd_code,
+			      struct sk_buff *req, struct sk_buff *resp,
+			      int resp_len,
+			      pn533_send_async_complete_t complete_cb,
+			      void *complete_cb_context)
+{
+	struct pn533_cmd *cmd;
+	struct pn533_send_async_complete_arg *arg;
+	int rc = 0;
+
+	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);
+
+	arg = kzalloc(sizeof(arg), GFP_KERNEL);
+	if (!arg)
+		return -ENOMEM;
+
+	arg->complete_cb = complete_cb;
+	arg->complete_cb_context = complete_cb_context;
+	arg->resp = resp;
+	arg->req = req;
+
+	pn533_build_cmd_frame(cmd_code, req);
+
+	mutex_lock(&dev->cmd_lock);
+
+	if (!dev->cmd_pending) {
+		rc = __pn533_send_cmd_frame_async(dev,
+						  (struct pn533_frame *)req->data,
+						  (struct pn533_frame *)resp->data,
+						  resp_len, pn533_send_async_complete,
+						  arg);
+		if (rc)
+			goto error;
+
+		dev->cmd_pending = 1;
+		goto unlock;
+	}
+
+	nfc_dev_dbg(&dev->interface->dev, "%s Queueing command", __func__);
+
+	cmd = kzalloc(sizeof(struct pn533_cmd), GFP_KERNEL);
+	if (!cmd) {
+		rc = -ENOMEM;
+		goto error;
+	}
+
+	INIT_LIST_HEAD(&cmd->queue);
+	cmd->cmd_code = cmd_code;
+	cmd->req = req;
+	cmd->resp = resp;
+	cmd->arg = arg;
+
+	list_add_tail(&cmd->queue, &dev->cmd_queue);
+
+	goto unlock;
+
+error:
+	kfree(arg);
+unlock:
+	mutex_unlock(&dev->cmd_lock);
+	return rc;
+}
+
+static int pn533_send_cmd_async(struct pn533 *dev, u8 cmd_code,
+				struct sk_buff *req,
+				pn533_send_async_complete_t complete_cb,
+				void *complete_cb_context)
+{
+	struct sk_buff *resp;
+	int rc;
+
+	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);
+
+	resp = alloc_skb(PN533_NORMAL_FRAME_MAX_LEN, GFP_KERNEL);
+	if (!resp)
+		return -ENOMEM;
+
+	rc = __pn533_send_async(dev, cmd_code, req, resp,
+				PN533_NORMAL_FRAME_MAX_LEN,
+				complete_cb, complete_cb_context);
+	if (rc)
+		dev_kfree_skb(resp);
+
+	return rc;
+}
+
 static void pn533_wq_cmd(struct work_struct *work)
 {
 	struct pn533 *dev = container_of(work, struct pn533, cmd_work);
@@ -697,9 +849,17 @@ static void pn533_wq_cmd(struct work_struct *work)
 
 	mutex_unlock(&dev->cmd_lock);
 
-	__pn533_send_cmd_frame_async(dev, cmd->out_frame, cmd->in_frame,
-				     cmd->in_frame_len, cmd->cmd_complete,
-				     cmd->arg);
+	if (cmd->cmd_code != PN533_CMD_UNDEF)
+		__pn533_send_cmd_frame_async(dev,
+					     (struct pn533_frame *)cmd->req->data,
+					     (struct pn533_frame *)cmd->resp->data,
+					     PN533_NORMAL_FRAME_MAX_LEN,
+					     pn533_send_async_complete,
+					     cmd->arg);
+	else
+		__pn533_send_cmd_frame_async(dev, cmd->out_frame, cmd->in_frame,
+					     cmd->in_frame_len,
+					     cmd->cmd_complete, cmd->arg);
 
 	kfree(cmd);
 }
@@ -740,6 +900,7 @@ static int pn533_send_cmd_frame_async(struct pn533 *dev,
 	cmd->out_frame = out_frame;
 	cmd->in_frame = in_frame;
 	cmd->in_frame_len = in_frame_len;
+	cmd->cmd_code = PN533_CMD_UNDEF;
 	cmd->cmd_complete = cmd_complete;
 	cmd->arg = arg;