static int intel_ntb4_link_enable()

in hw/intel/ntb_hw_gen4.c [416:478]

• 43 lines of code
• 5 McCabe index (conditional complexity)

static int intel_ntb4_link_enable(struct ntb_dev *ntb,
		enum ntb_speed max_speed, enum ntb_width max_width)
{
	struct intel_ntb_dev *ndev;
	u32 ntb_ctl, ppd0;
	u16 lnkctl;

	ndev = container_of(ntb, struct intel_ntb_dev, ntb);

	dev_dbg(&ntb->pdev->dev,
			"Enabling link with max_speed %d max_width %d\n",
			max_speed, max_width);

	if (max_speed != NTB_SPEED_AUTO)
		dev_dbg(&ntb->pdev->dev,
				"ignoring max_speed %d\n", max_speed);
	if (max_width != NTB_WIDTH_AUTO)
		dev_dbg(&ntb->pdev->dev,
				"ignoring max_width %d\n", max_width);

	if (!(ndev->hwerr_flags & NTB_HWERR_LTR_BAD)) {
		u32 ltr;

		/* Setup active snoop LTR values */
		ltr = NTB_LTR_ACTIVE_REQMNT | NTB_LTR_ACTIVE_VAL | NTB_LTR_ACTIVE_LATSCALE;
		/* Setup active non-snoop values */
		ltr = (ltr << NTB_LTR_NS_SHIFT) | ltr;
		iowrite32(ltr, ndev->self_mmio + GEN4_LTR_ACTIVE_OFFSET);

		/* Setup idle snoop LTR values */
		ltr = NTB_LTR_IDLE_VAL | NTB_LTR_IDLE_LATSCALE | NTB_LTR_IDLE_REQMNT;
		/* Setup idle non-snoop values */
		ltr = (ltr << NTB_LTR_NS_SHIFT) | ltr;
		iowrite32(ltr, ndev->self_mmio + GEN4_LTR_IDLE_OFFSET);

		/* setup PCIe LTR to active */
		iowrite8(NTB_LTR_SWSEL_ACTIVE, ndev->self_mmio + GEN4_LTR_SWSEL_OFFSET);
	}

	ntb_ctl = NTB_CTL_E2I_BAR23_SNOOP | NTB_CTL_I2E_BAR23_SNOOP;
	ntb_ctl |= NTB_CTL_E2I_BAR45_SNOOP | NTB_CTL_I2E_BAR45_SNOOP;
	iowrite32(ntb_ctl, ndev->self_mmio + ndev->reg->ntb_ctl);

	lnkctl = ioread16(ndev->self_mmio + GEN4_LINK_CTRL_OFFSET);
	lnkctl &= ~GEN4_LINK_CTRL_LINK_DISABLE;
	iowrite16(lnkctl, ndev->self_mmio + GEN4_LINK_CTRL_OFFSET);

	/* start link training in PPD0 */
	ppd0 = ioread32(ndev->self_mmio + GEN4_PPD0_OFFSET);
	ppd0 |= GEN4_PPD_LINKTRN;
	iowrite32(ppd0, ndev->self_mmio + GEN4_PPD0_OFFSET);

	/* make sure link training has started */
	ppd0 = ioread32(ndev->self_mmio + GEN4_PPD0_OFFSET);
	if (!(ppd0 & GEN4_PPD_LINKTRN)) {
		dev_warn(&ntb->pdev->dev, "Link is not training\n");
		return -ENXIO;
	}

	ndev->dev_up = 1;

	return 0;
}