static int pn533_dep_link_up()

in pn533/pn533.c [1956:2036]

• 62 lines of code
• 12 McCabe index (conditional complexity)

static int pn533_dep_link_up(struct nfc_dev *nfc_dev, struct nfc_target *target,
			     u8 comm_mode, u8 *gb, size_t gb_len)
{
	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
	struct sk_buff *skb;
	int rc, skb_len;
	u8 *next, *arg, nfcid3[NFC_NFCID3_MAXSIZE];
	u8 passive_data[PASSIVE_DATA_LEN] = {0x00, 0xff, 0xff, 0x00, 0x3};

	if (dev->poll_mod_count) {
		nfc_err(dev->dev,
			"Cannot bring the DEP link up while polling\n");
		return -EBUSY;
	}

	if (dev->tgt_active_prot) {
		nfc_err(dev->dev,
			"There is already an active target\n");
		return -EBUSY;
	}

	skb_len = 3 + gb_len; /* ActPass + BR + Next */
	skb_len += PASSIVE_DATA_LEN;

	/* NFCID3 */
	skb_len += NFC_NFCID3_MAXSIZE;
	if (target && !target->nfcid2_len) {
		nfcid3[0] = 0x1;
		nfcid3[1] = 0xfe;
		get_random_bytes(nfcid3 + 2, 6);
	}

	skb = pn533_alloc_skb(dev, skb_len);
	if (!skb)
		return -ENOMEM;

	skb_put_u8(skb, !comm_mode);  /* ActPass */
	skb_put_u8(skb, 0x02);  /* 424 kbps */

	next = skb_put(skb, 1);  /* Next */
	*next = 0;

	/* Copy passive data */
	skb_put_data(skb, passive_data, PASSIVE_DATA_LEN);
	*next |= 1;

	/* Copy NFCID3 (which is NFCID2 from SENSF_RES) */
	if (target && target->nfcid2_len)
		memcpy(skb_put(skb, NFC_NFCID3_MAXSIZE), target->nfcid2,
		       target->nfcid2_len);
	else
		skb_put_data(skb, nfcid3, NFC_NFCID3_MAXSIZE);
	*next |= 2;

	if (gb != NULL && gb_len > 0) {
		skb_put_data(skb, gb, gb_len);
		*next |= 4; /* We have some Gi */
	} else {
		*next = 0;
	}

	arg = kmalloc(sizeof(*arg), GFP_KERNEL);
	if (!arg) {
		dev_kfree_skb(skb);
		return -ENOMEM;
	}

	*arg = !comm_mode;

	pn533_rf_field(dev->nfc_dev, 0);

	rc = pn533_send_cmd_async(dev, PN533_CMD_IN_JUMP_FOR_DEP, skb,
				  pn533_in_dep_link_up_complete, arg);

	if (rc < 0) {
		dev_kfree_skb(skb);
		kfree(arg);
	}

	return rc;
}