Merge branch 'pci/controller/cadence'

- Wait for link retrain to complete when working around the J721E i2085
  erratum with Gen2 mode (Siddharth Vadapalli)

* pci/controller/cadence:
  PCI: cadence: Fix Gen2 Link Retraining process

Author: bjorn-helgaas

drivers/pci/controller/cadence/pcie-cadence-host.c

@@ -12,6 +12,8 @@
 
 #include "pcie-cadence.h"
 
+#define LINK_RETRAIN_TIMEOUT HZ
+
 static u64 bar_max_size[] = {
 	[RP_BAR0] = _ULL(128 * SZ_2G),
 	[RP_BAR1] = SZ_2G,
@@ -77,6 +79,27 @@ static struct pci_ops cdns_pcie_host_ops = {
 	.write		= pci_generic_config_write,
 };
 
+static int cdns_pcie_host_training_complete(struct cdns_pcie *pcie)
+{
+	u32 pcie_cap_off = CDNS_PCIE_RP_CAP_OFFSET;
+	unsigned long end_jiffies;
+	u16 lnk_stat;
+
+	/* Wait for link training to complete. Exit after timeout. */
+	end_jiffies = jiffies + LINK_RETRAIN_TIMEOUT;
+	do {
+		lnk_stat = cdns_pcie_rp_readw(pcie, pcie_cap_off + PCI_EXP_LNKSTA);
+		if (!(lnk_stat & PCI_EXP_LNKSTA_LT))
+			break;
+		usleep_range(0, 1000);
+	} while (time_before(jiffies, end_jiffies));
+
+	if (!(lnk_stat & PCI_EXP_LNKSTA_LT))
+		return 0;
+
+	return -ETIMEDOUT;
+}
+
 static int cdns_pcie_host_wait_for_link(struct cdns_pcie *pcie)
 {
 	struct device *dev = pcie->dev;
@@ -118,6 +141,10 @@ static int cdns_pcie_retrain(struct cdns_pcie *pcie)
 		cdns_pcie_rp_writew(pcie, pcie_cap_off + PCI_EXP_LNKCTL,
 				    lnk_ctl);
 
+		ret = cdns_pcie_host_training_complete(pcie);
+		if (ret)
+			return ret;
+
 		ret = cdns_pcie_host_wait_for_link(pcie);
 	}
 	return ret;