PCI: pciehp: Add Disable/enable link functions

Will use it during power off/on of slots

Signed-off-by: Yinghai Lu <yinghai.lu@oracle.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 4ebdc1de2cb4..db33688af588 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -352,6 +352,42 @@ int pciehp_check_link_status(struct controller *ctrl)
         return retval;
 }
 
+static int __pciehp_link_set(struct controller *ctrl, bool enable)
+{
+        u16 lnk_ctrl;
+        int retval = 0;
+
+        retval = pciehp_readw(ctrl, PCI_EXP_LNKCTL, &lnk_ctrl);
+        if (retval) {
+                ctrl_err(ctrl, "Cannot read LNKCTRL register\n");
+                return retval;
+        }
+
+        if (enable)
+                lnk_ctrl &= ~PCI_EXP_LNKCTL_LD;
+        else
+                lnk_ctrl |= PCI_EXP_LNKCTL_LD;
+
+        retval = pciehp_writew(ctrl, PCI_EXP_LNKCTL, lnk_ctrl);
+        if (retval) {
+                ctrl_err(ctrl, "Cannot write LNKCTRL register\n");
+                return retval;
+        }
+        ctrl_dbg(ctrl, "%s: lnk_ctrl = %x\n", __func__, lnk_ctrl);
+
+        return retval;
+}
+
+static int pciehp_link_enable(struct controller *ctrl)
+{
+        return __pciehp_link_set(ctrl, true);
+}
+
+static int pciehp_link_disable(struct controller *ctrl)
+{
+        return __pciehp_link_set(ctrl, false);
+}
+
 int pciehp_get_attention_status(struct slot *slot, u8 *status)
 {
         struct controller *ctrl = slot->ctrl;