3 files changed, 56 insertions, 12 deletions

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 80fc98acf097..2c05f2f7d1c0 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -779,9 +779,7 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 	/* Start LTSSM. */
 	imx6_pcie_ltssm_enable(dev);
 
-	ret = dw_pcie_wait_for_link(pci);
-	if (ret)
-		goto err_reset_phy;
+	dw_pcie_wait_for_link(pci);
 
 	if (pci->link_gen == 2) {
 		/* Allow Gen2 mode after the link is up. */
@@ -817,11 +815,7 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 		}
 
 		/* Make sure link training is finished as well! */
-		ret = dw_pcie_wait_for_link(pci);
-		if (ret) {
-			dev_err(dev, "Failed to bring link up!\n");
-			goto err_reset_phy;
-		}
+		dw_pcie_wait_for_link(pci);
 	} else {
 		dev_info(dev, "Link: Gen2 disabled\n");
 	}
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index a945f0c0e73d..3254f60d1713 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -671,10 +671,11 @@ void dw_pcie_iatu_detect(struct dw_pcie *pci)
 		if (!pci->atu_base) {
 			struct resource *res =
 				platform_get_resource_byname(pdev, IORESOURCE_MEM, "atu");
-			if (res)
+			if (res) {
 				pci->atu_size = resource_size(res);
-			pci->atu_base = devm_ioremap_resource(dev, res);
-			if (IS_ERR(pci->atu_base))
+				pci->atu_base = devm_ioremap_resource(dev, res);
+			}
+			if (!pci->atu_base || IS_ERR(pci->atu_base))
 				pci->atu_base = pci->dbi_base + DEFAULT_DBI_ATU_OFFSET;
 		}
 
diff --git a/drivers/pci/controller/dwc/pcie-fu740.c b/drivers/pci/controller/dwc/pcie-fu740.c
index 00cde9a248b5..78d002be4f82 100644
--- a/drivers/pci/controller/dwc/pcie-fu740.c
+++ b/drivers/pci/controller/dwc/pcie-fu740.c
@@ -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)