PCI: pciehp: change wait time for valid configuration access

Naoki Yanagimoto reported that configuration read on some hot-added
PCIe device returns invalid value. This patch fixes this problem.

According to the PCIe spec, software must wait for at least 1 second
to judge if the hot-added device is broken after Data Link Layer State
Changed Event. This patch changes pciehp driver to wait for 1 second
after the Data Link Layer State Changed Event is detected before
initiating a configuration access instead of 100 ms.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Naoki Yanagimoto <yanagimoto@np.css.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 5 insertions, 9 deletions

diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 085dbb5fc168..1e9c9aacc3a6 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -213,6 +213,9 @@ static int board_added(struct slot *p_slot)
                 goto err_exit;
         }
 
+        /* Wait for 1 second after checking link training status */
+        msleep(1000);
+
         /* Check for a power fault */
         if (ctrl->power_fault_detected || pciehp_query_power_fault(p_slot)) {
                 ctrl_err(ctrl, "Power fault on slot %s\n", slot_name(p_slot));
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 50a23da5d24d..96dc4734e4af 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -275,16 +275,9 @@ int pciehp_check_link_status(struct controller *ctrl)
          * hot-plug capable downstream port. But old controller might
          * not implement it. In this case, we wait for 1000 ms.
          */
-        if (ctrl->link_active_reporting){
-                /* Wait for Data Link Layer Link Active bit to be set */
+        if (ctrl->link_active_reporting)
                 pcie_wait_link_active(ctrl);
-                /*
-                 * We must wait for 100 ms after the Data Link Layer
-                 * Link Active bit reads 1b before initiating a
-                 * configuration access to the hot added device.
-                 */
-                msleep(100);
-        } else
+        else
                 msleep(1000);
 
         retval = pciehp_readw(ctrl, PCI_EXP_LNKSTA, &lnk_status);