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Commit 6ff73fd2 authored by Samuel Ortiz's avatar Samuel Ortiz Committed by John W. Linville
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NFC: pn533 Rx chaining support 



When buffers on the receiption path exceed 262 bytes, the pn533 uses
a chaining mechanism where the initiator has to send NULL data frames
to fetch the remaining frames.
We do that from a workqueue context while holding the cmd lock. Once the
MI bit is gone, we aggregate the queued received skbs.

Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 4849f85e

drivers/nfc/pn533.c

+128 −16
Original line number Diff line number Diff line
@@ -266,8 +266,11 @@ struct pn533 { 
	int in_maxlen;

	struct pn533_frame *in_frame;



	struct sk_buff_head resp_q;



	struct workqueue_struct	*wq;

	struct work_struct cmd_work;

	struct work_struct mi_work;

	struct pn533_frame *wq_in_frame;

	int wq_in_error;
@@ -1256,6 +1259,8 @@ static void pn533_deactivate_target(struct nfc_dev *nfc_dev, u32 target_idx) 


	dev->tgt_active_prot = 0;



	skb_queue_purge(&dev->resp_q);



	pn533_tx_frame_init(dev->out_frame, PN533_CMD_IN_RELEASE);



	tg = 1;
@@ -1454,11 +1459,49 @@ struct pn533_data_exchange_arg { 
	void *cb_context;

};



static struct sk_buff *pn533_build_response(struct pn533 *dev)

{

	struct sk_buff *skb, *tmp, *t;

	unsigned int skb_len = 0, tmp_len = 0;



	nfc_dev_dbg(&dev->interface->dev, "%s\n", __func__);



	if (skb_queue_empty(&dev->resp_q))

		return NULL;



	if (skb_queue_len(&dev->resp_q) == 1) {

		skb = skb_dequeue(&dev->resp_q);

		goto out;

	}



	skb_queue_walk_safe(&dev->resp_q, tmp, t)

		skb_len += tmp->len;



	nfc_dev_dbg(&dev->interface->dev, "%s total length %d\n",

		    __func__, skb_len);



	skb = alloc_skb(skb_len, GFP_KERNEL);

	if (skb == NULL)

		goto out;



	skb_put(skb, skb_len);



	skb_queue_walk_safe(&dev->resp_q, tmp, t) {

		memcpy(skb->data + tmp_len, tmp->data, tmp->len);

		tmp_len += tmp->len;

	}



out:

	skb_queue_purge(&dev->resp_q);



	return skb;

}



static int pn533_data_exchange_complete(struct pn533 *dev, void *_arg,

						u8 *params, int params_len)

{

	struct pn533_data_exchange_arg *arg = _arg;

	struct sk_buff *skb_resp = arg->skb_resp;

	struct sk_buff *skb = NULL, *skb_resp = arg->skb_resp;

	struct pn533_frame *in_frame = (struct pn533_frame *) skb_resp->data;

	int err = 0;

	u8 status;
@@ -1466,15 +1509,13 @@ static int pn533_data_exchange_complete(struct pn533 *dev, void *_arg, 


	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);



	dev_kfree_skb_irq(arg->skb_out);

	dev_kfree_skb(arg->skb_out);



	if (params_len < 0) { /* error */

		err = params_len;

		goto error;

	}



	skb_put(skb_resp, PN533_FRAME_SIZE(in_frame));



	status = params[0];



	cmd_ret = status & PN533_CMD_RET_MASK;
@@ -1485,25 +1526,27 @@ static int pn533_data_exchange_complete(struct pn533 *dev, void *_arg, 
		goto error;

	}



	skb_put(skb_resp, PN533_FRAME_SIZE(in_frame));

	skb_pull(skb_resp, PN533_CMD_DATAEXCH_HEAD_LEN);

	skb_trim(skb_resp, skb_resp->len - PN533_FRAME_TAIL_SIZE);

	skb_queue_tail(&dev->resp_q, skb_resp);



	if (status & PN533_CMD_MI_MASK) {

		/* TODO: Implement support to multi-part data exchange */

		nfc_dev_err(&dev->interface->dev, "Multi-part message not yet"

								" supported");

		/* Prevent the other messages from controller */

		pn533_send_ack(dev, GFP_ATOMIC);

		err = -ENOSYS;

		goto error;

		queue_work(dev->wq, &dev->mi_work);

		return -EINPROGRESS;

	}



	skb_pull(skb_resp, PN533_CMD_DATAEXCH_HEAD_LEN);

	skb_trim(skb_resp, skb_resp->len - PN533_FRAME_TAIL_SIZE);

	skb = pn533_build_response(dev);

	if (skb == NULL)

		goto error;



	arg->cb(arg->cb_context, skb_resp, 0);

	arg->cb(arg->cb_context, skb, 0);

	kfree(arg);

	return 0;



error:

	dev_kfree_skb_irq(skb_resp);

	skb_queue_purge(&dev->resp_q);

	dev_kfree_skb(skb_resp);

	arg->cb(arg->cb_context, NULL, err);

	kfree(arg);

	return 0;
@@ -1578,6 +1621,68 @@ error: 
	return rc;

}



static void pn533_wq_mi_recv(struct work_struct *work)

{

	struct pn533 *dev = container_of(work, struct pn533, mi_work);

	struct sk_buff *skb_cmd;

	struct pn533_data_exchange_arg *arg = dev->cmd_complete_arg;

	struct pn533_frame *out_frame, *in_frame;

	struct sk_buff *skb_resp;

	int skb_resp_len;

	int rc;



	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);



	/* This is a zero payload size skb */

	skb_cmd = alloc_skb(PN533_CMD_DATAEXCH_HEAD_LEN + PN533_FRAME_TAIL_SIZE,

			    GFP_KERNEL);

	if (skb_cmd == NULL)

		goto error_cmd;



	skb_reserve(skb_cmd, PN533_CMD_DATAEXCH_HEAD_LEN);



	rc = pn533_data_exchange_tx_frame(dev, skb_cmd);

	if (rc)

		goto error_frame;



	skb_resp_len = PN533_CMD_DATAEXCH_HEAD_LEN +

			PN533_CMD_DATAEXCH_DATA_MAXLEN +

			PN533_FRAME_TAIL_SIZE;

	skb_resp = alloc_skb(skb_resp_len, GFP_KERNEL);

	if (!skb_resp) {

		rc = -ENOMEM;

		goto error_frame;

	}



	in_frame = (struct pn533_frame *) skb_resp->data;

	out_frame = (struct pn533_frame *) skb_cmd->data;



	arg->skb_resp = skb_resp;

	arg->skb_out = skb_cmd;



	rc = __pn533_send_cmd_frame_async(dev, out_frame, in_frame,

					  skb_resp_len,

					  pn533_data_exchange_complete,

					  dev->cmd_complete_arg, GFP_KERNEL);

	if (!rc)

		return;



	nfc_dev_err(&dev->interface->dev, "Error %d when trying to"

						" perform data_exchange", rc);



	kfree_skb(skb_resp);



error_frame:

	kfree_skb(skb_cmd);



error_cmd:

	pn533_send_ack(dev, GFP_KERNEL);



	kfree(arg);



	up(&dev->cmd_lock);

}



static int pn533_set_configuration(struct pn533 *dev, u8 cfgitem, u8 *cfgdata,

								u8 cfgdata_len)

{
@@ -1676,10 +1781,15 @@ static int pn533_probe(struct usb_interface *interface, 
			pn533_send_complete, dev);



	INIT_WORK(&dev->cmd_work, pn533_wq_cmd_complete);

	dev->wq = create_singlethread_workqueue("pn533");

	INIT_WORK(&dev->mi_work, pn533_wq_mi_recv);

	dev->wq = alloc_workqueue("pn533",

				  WQ_NON_REENTRANT | WQ_UNBOUND | WQ_MEM_RECLAIM,

				  1);

	if (dev->wq == NULL)

		goto error;



	skb_queue_head_init(&dev->resp_q);



	usb_set_intfdata(interface, dev);



	pn533_tx_frame_init(dev->out_frame, PN533_CMD_GET_FIRMWARE_VERSION);
@@ -1756,6 +1866,8 @@ static void pn533_disconnect(struct usb_interface *interface) 


	destroy_workqueue(dev->wq);



	skb_queue_purge(&dev->resp_q);



	kfree(dev->in_frame);

	usb_free_urb(dev->in_urb);

	kfree(dev->out_frame);