PCI: altera: Poll for link up status after retraining the link

Some PCIe devices take a long time to reach link up state after retrain.
Poll for link up status after retraining the link.  This is to make sure
the link is up before we access configuration space.

[bhelgaas: changelog]
Signed-off-by: Ley Foon Tan <lftan@altera.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
index b61025ee07de..e4154b2a23ce 100644
--- a/drivers/pci/host/pcie-altera.c
+++ b/drivers/pci/host/pcie-altera.c
@@ -61,6 +61,8 @@
 #define TLP_LOOP                        500
 #define RP_DEVFN                        0
 
+#define LINK_UP_TIMEOUT                 5000
+
 #define INTX_NUM                        4
 
 #define DWORD_MASK                      3
@@ -101,6 +103,7 @@ static void altera_pcie_retrain(struct pci_dev *dev)
 {
         u16 linkcap, linkstat;
         struct altera_pcie *pcie = dev->bus->sysdata;
+        int timeout =  0;
 
         if (!altera_pcie_link_is_up(pcie))
                 return;
@@ -115,9 +118,16 @@ static void altera_pcie_retrain(struct pci_dev *dev)
                 return;
 
         pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &linkstat);
-        if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB)
+        if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) {
                 pcie_capability_set_word(dev, PCI_EXP_LNKCTL,
                                          PCI_EXP_LNKCTL_RL);
+                while (!altera_pcie_link_is_up(pcie)) {
+                        timeout++;
+                        if (timeout > LINK_UP_TIMEOUT)
+                                break;
+                        udelay(5);
+                }
+        }
 }
 DECLARE_PCI_FIXUP_EARLY(0x1172, PCI_ANY_ID, altera_pcie_retrain);