static int idt_scan_ports()

in hw/idt/ntb_hw_idt.c [480:540]

• 38 lines of code
• 9 McCabe index (conditional complexity)

static int idt_scan_ports(struct idt_ntb_dev *ndev)
{
	unsigned char pidx, port, part;
	u32 data, portsts, partsts;

	/* Retrieve the local port number */
	data = idt_nt_read(ndev, IDT_NT_PCIELCAP);
	ndev->port = GET_FIELD(PCIELCAP_PORTNUM, data);

	/* Retrieve the local partition number */
	portsts = idt_sw_read(ndev, portdata_tbl[ndev->port].sts);
	ndev->part = GET_FIELD(SWPORTxSTS_SWPART, portsts);

	/* Initialize port/partition -> index tables with invalid values */
	memset(ndev->port_idx_map, -EINVAL, sizeof(ndev->port_idx_map));
	memset(ndev->part_idx_map, -EINVAL, sizeof(ndev->part_idx_map));

	/*
	 * Walk over all the possible ports checking whether any of them has
	 * NT-function activated
	 */
	ndev->peer_cnt = 0;
	for (pidx = 0; pidx < ndev->swcfg->port_cnt; pidx++) {
		port = ndev->swcfg->ports[pidx];
		/* Skip local port */
		if (port == ndev->port)
			continue;

		/* Read the port status register to get it partition */
		portsts = idt_sw_read(ndev, portdata_tbl[port].sts);
		part = GET_FIELD(SWPORTxSTS_SWPART, portsts);

		/* Retrieve the partition status */
		partsts = idt_sw_read(ndev, partdata_tbl[part].sts);
		/* Check if partition state is active and port has NTB */
		if (IS_FLD_SET(SWPARTxSTS_STATE, partsts, ACT) &&
		    (IS_FLD_SET(SWPORTxSTS_MODE, portsts, NT) ||
		     IS_FLD_SET(SWPORTxSTS_MODE, portsts, USNT) ||
		     IS_FLD_SET(SWPORTxSTS_MODE, portsts, USNTDMA) ||
		     IS_FLD_SET(SWPORTxSTS_MODE, portsts, NTDMA))) {
			/* Save the port and partition numbers */
			ndev->peers[ndev->peer_cnt].port = port;
			ndev->peers[ndev->peer_cnt].part = part;
			/* Fill in the port/partition -> index tables */
			ndev->port_idx_map[port] = ndev->peer_cnt;
			ndev->part_idx_map[part] = ndev->peer_cnt;
			ndev->peer_cnt++;
		}
	}

	dev_dbg(&ndev->ntb.pdev->dev, "Local port: %hhu, num of peers: %hhu\n",
		ndev->port, ndev->peer_cnt);

	/* It's useless to have this driver loaded if there is no any peer */
	if (ndev->peer_cnt == 0) {
		dev_warn(&ndev->ntb.pdev->dev, "No active peer found\n");
		return -ENODEV;
	}

	return 0;
}