Commit d93fefad authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'pci/host/fu740' 

- Drop redundant '-gpios' from DT GPIO lookup (Ben Dooks)

- Force 2.5GT/s for initial device probe to workaround enumeration issue on
  SiFive Unmatched board (Ben Dooks)

* pci/host/fu740:
  PCI: fu740: Force 2.5GT/s for initial device probe
  PCI: fu740: Drop redundant '-gpios' from DT GPIO lookup
parents a69e89ba a382c757

drivers/pci/controller/dwc/pcie-fu740.c

+52 −3
Original line number Diff line number Diff line
@@ -181,10 +181,59 @@ static int fu740_pcie_start_link(struct dw_pcie *pci) 
{

	struct device *dev = pci->dev;

	struct fu740_pcie *afp = dev_get_drvdata(dev);

	u8 cap_exp = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);

	int ret;

	u32 orig, tmp;



	/*

	 * Force 2.5GT/s when starting the link, due to some devices not

	 * probing at higher speeds. This happens with the PCIe switch

	 * on the Unmatched board when U-Boot has not initialised the PCIe.

	 * The fix in U-Boot is to force 2.5GT/s, which then gets cleared

	 * by the soft reset done by this driver.

	 */

	dev_dbg(dev, "cap_exp at %x\n", cap_exp);

	dw_pcie_dbi_ro_wr_en(pci);



	tmp = dw_pcie_readl_dbi(pci, cap_exp + PCI_EXP_LNKCAP);

	orig = tmp & PCI_EXP_LNKCAP_SLS;

	tmp &= ~PCI_EXP_LNKCAP_SLS;

	tmp |= PCI_EXP_LNKCAP_SLS_2_5GB;

	dw_pcie_writel_dbi(pci, cap_exp + PCI_EXP_LNKCAP, tmp);



	/* Enable LTSSM */

	writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_APP_LTSSM_ENABLE);

	return 0;



	ret = dw_pcie_wait_for_link(pci);

	if (ret) {

		dev_err(dev, "error: link did not start\n");

		goto err;

	}



	tmp = dw_pcie_readl_dbi(pci, cap_exp + PCI_EXP_LNKCAP);

	if ((tmp & PCI_EXP_LNKCAP_SLS) != orig) {

		dev_dbg(dev, "changing speed back to original\n");



		tmp &= ~PCI_EXP_LNKCAP_SLS;

		tmp |= orig;

		dw_pcie_writel_dbi(pci, cap_exp + PCI_EXP_LNKCAP, tmp);



		tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);

		tmp |= PORT_LOGIC_SPEED_CHANGE;

		dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp);



		ret = dw_pcie_wait_for_link(pci);

		if (ret) {

			dev_err(dev, "error: link did not start at new speed\n");

			goto err;

		}

	}



	ret = 0;

err:

	WARN_ON(ret);	/* we assume that errors will be very rare */

	dw_pcie_dbi_ro_wr_dis(pci);

	return ret;

}



static int fu740_pcie_host_init(struct pcie_port *pp)
@@ -259,11 +308,11 @@ static int fu740_pcie_probe(struct platform_device *pdev) 
		return PTR_ERR(afp->mgmt_base);



	/* Fetch GPIOs */

	afp->reset = devm_gpiod_get_optional(dev, "reset-gpios", GPIOD_OUT_LOW);

	afp->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);

	if (IS_ERR(afp->reset))

		return dev_err_probe(dev, PTR_ERR(afp->reset), "unable to get reset-gpios\n");



	afp->pwren = devm_gpiod_get_optional(dev, "pwren-gpios", GPIOD_OUT_LOW);

	afp->pwren = devm_gpiod_get_optional(dev, "pwren", GPIOD_OUT_LOW);

	if (IS_ERR(afp->pwren))

		return dev_err_probe(dev, PTR_ERR(afp->pwren), "unable to get pwren-gpios\n");