static int pn533_start_poll()

in pn533/pn533.c [1626:1739]

• 90 lines of code
• 22 McCabe index (conditional complexity)

static int pn533_start_poll(struct nfc_dev *nfc_dev,
			    u32 im_protocols, u32 tm_protocols)
{
	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
	struct pn533_poll_modulations *cur_mod;
	struct sk_buff *skb;
	u8 rand_mod;
	int rc;

	dev_dbg(dev->dev,
		"%s: im protocols 0x%x tm protocols 0x%x\n",
		__func__, im_protocols, tm_protocols);

	if (dev->tgt_active_prot) {
		nfc_err(dev->dev,
			"Cannot poll with a target already activated\n");
		return -EBUSY;
	}

	if (dev->tgt_mode) {
		nfc_err(dev->dev,
			"Cannot poll while already being activated\n");
		return -EBUSY;
	}

	if (tm_protocols) {
		dev->gb = nfc_get_local_general_bytes(nfc_dev, &dev->gb_len);
		if (dev->gb == NULL)
			tm_protocols = 0;
	}

	dev->poll_protocols = im_protocols;
	dev->listen_protocols = tm_protocols;
	if (dev->device_type == PN533_DEVICE_PN532_AUTOPOLL) {
		skb = pn533_alloc_skb(dev, 4 + 6);
		if (!skb)
			return -ENOMEM;

		*((u8 *)skb_put(skb, sizeof(u8))) =
			PN532_AUTOPOLL_POLLNR_INFINITE;
		*((u8 *)skb_put(skb, sizeof(u8))) = PN532_AUTOPOLL_PERIOD;

		if ((im_protocols & NFC_PROTO_MIFARE_MASK) &&
				(im_protocols & NFC_PROTO_ISO14443_MASK) &&
				(im_protocols & NFC_PROTO_NFC_DEP_MASK))
			*((u8 *)skb_put(skb, sizeof(u8))) =
				PN532_AUTOPOLL_TYPE_GENERIC_106;
		else {
			if (im_protocols & NFC_PROTO_MIFARE_MASK)
				*((u8 *)skb_put(skb, sizeof(u8))) =
					PN532_AUTOPOLL_TYPE_MIFARE;

			if (im_protocols & NFC_PROTO_ISO14443_MASK)
				*((u8 *)skb_put(skb, sizeof(u8))) =
					PN532_AUTOPOLL_TYPE_ISOA;

			if (im_protocols & NFC_PROTO_NFC_DEP_MASK) {
				*((u8 *)skb_put(skb, sizeof(u8))) =
					PN532_AUTOPOLL_TYPE_DEP_PASSIVE_106;
				*((u8 *)skb_put(skb, sizeof(u8))) =
					PN532_AUTOPOLL_TYPE_DEP_PASSIVE_212;
				*((u8 *)skb_put(skb, sizeof(u8))) =
					PN532_AUTOPOLL_TYPE_DEP_PASSIVE_424;
			}
		}

		if (im_protocols & NFC_PROTO_FELICA_MASK ||
				im_protocols & NFC_PROTO_NFC_DEP_MASK) {
			*((u8 *)skb_put(skb, sizeof(u8))) =
				PN532_AUTOPOLL_TYPE_FELICA212;
			*((u8 *)skb_put(skb, sizeof(u8))) =
				PN532_AUTOPOLL_TYPE_FELICA424;
		}

		if (im_protocols & NFC_PROTO_JEWEL_MASK)
			*((u8 *)skb_put(skb, sizeof(u8))) =
				PN532_AUTOPOLL_TYPE_JEWEL;

		if (im_protocols & NFC_PROTO_ISO14443_B_MASK)
			*((u8 *)skb_put(skb, sizeof(u8))) =
				PN532_AUTOPOLL_TYPE_ISOB;

		if (tm_protocols)
			*((u8 *)skb_put(skb, sizeof(u8))) =
				PN532_AUTOPOLL_TYPE_DEP_ACTIVE_106;

		rc = pn533_send_cmd_async(dev, PN533_CMD_IN_AUTOPOLL, skb,
				pn533_autopoll_complete, NULL);

		if (rc < 0)
			dev_kfree_skb(skb);
		else
			dev->poll_mod_count++;

		return rc;
	}

	pn533_poll_create_mod_list(dev, im_protocols, tm_protocols);

	/* Do not always start polling from the same modulation */
	get_random_bytes(&rand_mod, sizeof(rand_mod));
	rand_mod %= dev->poll_mod_count;
	dev->poll_mod_curr = rand_mod;

	cur_mod = dev->poll_mod_active[dev->poll_mod_curr];

	rc = pn533_send_poll_frame(dev);

	/* Start listen timer */
	if (!rc && cur_mod->len == 0 && dev->poll_mod_count > 1)
		mod_timer(&dev->listen_timer, jiffies + PN533_LISTEN_TIME * HZ);

	return rc;
}