[PATCH] PCI Express Hotplug: clear sticky power-fault bit

Per the PCI Express spec, the power-fault-detected bit in the
slot status register can be set anytime hardware detects a power
fault, regardless of whether the slot has a device populated in
it or not. This bit is sticky and must be explicitly cleared.
This patch is needed to allow hot-add after such a power fault
has been detected.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 11 insertions, 15 deletions

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index c42b68d3aa24..6a61b9f286e1 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -59,7 +59,6 @@ struct slot {
         struct slot *next;
         u8 bus;
         u8 device;
-        u16 status;
         u32 number;
         u8 state;
         struct timer_list task_event;
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 5e582eca21d8..83c4b865718a 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -207,7 +207,6 @@ u8 pciehp_handle_power_fault(u8 hp_slot, void *inst_id)
                  * power fault Cleared
                  */
                 info("Power fault cleared on Slot(%d)\n", ctrl->first_slot + hp_slot);
-                p_slot->status = 0x00;
                 taskInfo->event_type = INT_POWER_FAULT_CLEAR;
         } else {
                 /*
@@ -215,8 +214,6 @@ u8 pciehp_handle_power_fault(u8 hp_slot, void *inst_id)
                  */
                 info("Power fault on Slot(%d)\n", ctrl->first_slot + hp_slot);
                 taskInfo->event_type = INT_POWER_FAULT;
-                /* set power fault status for this board */
-                p_slot->status = 0xFF;
                 info("power fault bit %x set\n", hp_slot);
         }
         if (rc)
@@ -317,13 +314,10 @@ static int board_added(struct slot *p_slot)
                 return rc;
         }
 
-        dbg("%s: slot status = %x\n", __FUNCTION__, p_slot->status);
-
         /* Check for a power fault */
-        if (p_slot->status == 0xFF) {
-                /* power fault occurred, but it was benign */
+        if (p_slot->hpc_ops->query_power_fault(p_slot)) {
+                dbg("%s: power fault detected\n", __FUNCTION__);
                 rc = POWER_FAILURE;
-                p_slot->status = 0;
                 goto err_exit;
         }
 
@@ -334,8 +328,6 @@ static int board_added(struct slot *p_slot)
                 goto err_exit;
         }
 
-        p_slot->status = 0;
-
         /*
          * Some PCI Express root ports require fixup after hot-plug operation.
          */
@@ -382,9 +374,6 @@ static int remove_board(struct slot *p_slot)
 
         dbg("In %s, hp_slot = %d\n", __FUNCTION__, hp_slot);
 
-        /* Change status to shutdown */
-        p_slot->status = 0x01;
-
         /* Wait for exclusive access to hardware */
         down(&ctrl->crit_sect);
 
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 2387e75da0fe..0b8b26beb163 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -750,7 +750,7 @@ static int hpc_power_on_slot(struct slot * slot)
 {
         struct php_ctlr_state_s *php_ctlr = slot->ctrl->hpc_ctlr_handle;
         u16 slot_cmd;
-        u16 slot_ctrl;
+        u16 slot_ctrl, slot_status;
 
         int retval = 0;
 
@@ -767,6 +767,14 @@ static int hpc_power_on_slot(struct slot * slot)
                 return -1;
         }
 
+        /* Clear sticky power-fault bit from previous power failures */
+        hp_register_read_word(php_ctlr->pci_dev,
+                        SLOT_STATUS(slot->ctrl->cap_base), slot_status);
+        slot_status &= PWR_FAULT_DETECTED;
+        if (slot_status)
+                hp_register_write_word(php_ctlr->pci_dev,
+                        SLOT_STATUS(slot->ctrl->cap_base), slot_status);
+
         retval = hp_register_read_word(php_ctlr->pci_dev, SLOT_CTRL(slot->ctrl->cap_base), slot_ctrl);
 
         if (retval) {