static int xeon_init_ntb()

in hw/intel/ntb_hw_gen1.c [1537:1641]

• 82 lines of code
• 14 McCabe index (conditional complexity)

static int xeon_init_ntb(struct intel_ntb_dev *ndev)
{
	struct device *dev = &ndev->ntb.pdev->dev;
	int rc;
	u32 ntb_ctl;

	if (ndev->bar4_split)
		ndev->mw_count = HSX_SPLIT_BAR_MW_COUNT;
	else
		ndev->mw_count = XEON_MW_COUNT;

	ndev->spad_count = XEON_SPAD_COUNT;
	ndev->db_count = XEON_DB_COUNT;
	ndev->db_link_mask = XEON_DB_LINK_BIT;

	switch (ndev->ntb.topo) {
	case NTB_TOPO_PRI:
		if (ndev->hwerr_flags & NTB_HWERR_SDOORBELL_LOCKUP) {
			dev_err(dev, "NTB Primary config disabled\n");
			return -EINVAL;
		}

		/* enable link to allow secondary side device to appear */
		ntb_ctl = ioread32(ndev->self_mmio + ndev->reg->ntb_ctl);
		ntb_ctl &= ~NTB_CTL_DISABLE;
		iowrite32(ntb_ctl, ndev->self_mmio + ndev->reg->ntb_ctl);

		/* use half the spads for the peer */
		ndev->spad_count >>= 1;
		ndev->self_reg = &xeon_pri_reg;
		ndev->peer_reg = &xeon_sec_reg;
		ndev->xlat_reg = &xeon_sec_xlat;
		break;

	case NTB_TOPO_SEC:
		if (ndev->hwerr_flags & NTB_HWERR_SDOORBELL_LOCKUP) {
			dev_err(dev, "NTB Secondary config disabled\n");
			return -EINVAL;
		}
		/* use half the spads for the peer */
		ndev->spad_count >>= 1;
		ndev->self_reg = &xeon_sec_reg;
		ndev->peer_reg = &xeon_pri_reg;
		ndev->xlat_reg = &xeon_pri_xlat;
		break;

	case NTB_TOPO_B2B_USD:
	case NTB_TOPO_B2B_DSD:
		ndev->self_reg = &xeon_pri_reg;
		ndev->peer_reg = &xeon_b2b_reg;
		ndev->xlat_reg = &xeon_sec_xlat;

		if (ndev->hwerr_flags & NTB_HWERR_SDOORBELL_LOCKUP) {
			ndev->peer_reg = &xeon_pri_reg;

			if (b2b_mw_idx < 0)
				ndev->b2b_idx = b2b_mw_idx + ndev->mw_count;
			else
				ndev->b2b_idx = b2b_mw_idx;

			if (ndev->b2b_idx >= ndev->mw_count) {
				dev_dbg(dev,
					"b2b_mw_idx %d invalid for mw_count %u\n",
					b2b_mw_idx, ndev->mw_count);
				return -EINVAL;
			}

			dev_dbg(dev, "setting up b2b mw idx %d means %d\n",
				b2b_mw_idx, ndev->b2b_idx);

		} else if (ndev->hwerr_flags & NTB_HWERR_B2BDOORBELL_BIT14) {
			dev_warn(dev, "Reduce doorbell count by 1\n");
			ndev->db_count -= 1;
		}

		if (ndev->ntb.topo == NTB_TOPO_B2B_USD) {
			rc = xeon_setup_b2b_mw(ndev,
					       &xeon_b2b_dsd_addr,
					       &xeon_b2b_usd_addr);
		} else {
			rc = xeon_setup_b2b_mw(ndev,
					       &xeon_b2b_usd_addr,
					       &xeon_b2b_dsd_addr);
		}
		if (rc)
			return rc;

		/* Enable Bus Master and Memory Space on the secondary side */
		iowrite16(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER,
			  ndev->self_mmio + XEON_SPCICMD_OFFSET);

		break;

	default:
		return -EINVAL;
	}

	ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1;

	ndev->reg->db_iowrite(ndev->db_valid_mask,
			      ndev->self_mmio +
			      ndev->self_reg->db_mask);

	return 0;
}