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

commit 3a928e98a833e1a470a60d2fedf3c55502185fb7 upstream.

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>
Cc: Claudius Heine <claudius.heine.ext@siemens.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
index b61025ee07de17a541b7acd2465a181fa708bcdc..e4154b2a23ce2db710a5d9f88ce7089e16f83207 100644 (file)
--- 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);