pciehp: workaround against Bad DLLP during power off

[linux-2.6-omap-h63xx.git] / drivers / pci / hotplug / pciehp_hpc.c

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index b2cde04ede1ad793a1c58d0a0cfcaa6691e75d33..6eba9b2cfb90b359fc1fb92b45408846b4694f6f 100644 (file)
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -636,15 +636,57 @@ static int hpc_power_on_slot(struct slot * slot)
        return retval;
 }
 
+static inline int pcie_mask_bad_dllp(struct controller *ctrl)
+{
+       struct pci_dev *dev = ctrl->pci_dev;
+       int pos;
+       u32 reg;
+
+       pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
+       if (!pos)
+               return 0;
+       pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, &reg);
+       if (reg & PCI_ERR_COR_BAD_DLLP)
+               return 0;
+       reg |= PCI_ERR_COR_BAD_DLLP;
+       pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, reg);
+       return 1;
+}
+
+static inline void pcie_unmask_bad_dllp(struct controller *ctrl)
+{
+       struct pci_dev *dev = ctrl->pci_dev;
+       u32 reg;
+       int pos;
+
+       pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
+       if (!pos)
+               return;
+       pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, &reg);
+       if (!(reg & PCI_ERR_COR_BAD_DLLP))
+               return;
+       reg &= ~PCI_ERR_COR_BAD_DLLP;
+       pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, reg);
+}
+
 static int hpc_power_off_slot(struct slot * slot)
 {
        struct controller *ctrl = slot->ctrl;
        u16 slot_cmd;
        u16 cmd_mask;
        int retval = 0;
+       int changed;
 
        dbg("%s: slot->hp_slot %x\n", __FUNCTION__, slot->hp_slot);
 
+       /*
+        * Set Bad DLLP Mask bit in Correctable Error Mask
+        * Register. This is the workaround against Bad DLLP error
+        * that sometimes happens during turning power off the slot
+        * which conforms to PCI Express 1.0a spec.
+        */
+       changed = pcie_mask_bad_dllp(ctrl);
+
        slot_cmd = POWER_OFF;
        cmd_mask = PWR_CTRL;
        /*
@@ -681,6 +723,9 @@ static int hpc_power_off_slot(struct slot * slot)
         */
        msleep(1000);
 
+       if (changed)
+               pcie_unmask_bad_dllp(ctrl);
+
        return retval;
 }