pciehp: block new requests from the device before power off

Disable Bus Master, SERR# and INTx to ensure that no new Requests will
be generated from the device before turning power off, in accordance
with the specification.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 21 insertions, 12 deletions

diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
index bc87d64a33f1..dd50713966d1 100644
--- a/drivers/pci/hotplug/pciehp_pci.c
+++ b/drivers/pci/hotplug/pciehp_pci.c
@@ -243,9 +243,13 @@ int pciehp_unconfigure_device(struct slot *p_slot)
         u8 bctl = 0;
         u8 presence = 0;
         struct pci_bus *parent = p_slot->ctrl->pci_dev->subordinate;
+        u16 command;
 
         dbg("%s: bus/dev = %x/%x\n", __FUNCTION__, p_slot->bus,
                                 p_slot->device);
+        ret = p_slot->hpc_ops->get_adapter_status(p_slot, &presence);
+        if (ret)
+                presence = 0;
 
         for (j = 0; j < 8; j++) {
                 struct pci_dev* temp = pci_get_slot(parent,
@@ -258,21 +262,26 @@ int pciehp_unconfigure_device(struct slot *p_slot)
                         pci_dev_put(temp);
                         continue;
                 }
-                if (temp->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
-                        ret = p_slot->hpc_ops->get_adapter_status(p_slot,
-                                                                &presence);
-                        if (!ret && presence) {
-                                pci_read_config_byte(temp, PCI_BRIDGE_CONTROL,
-                                        &bctl);
-                                if (bctl & PCI_BRIDGE_CTL_VGA) {
-                                        err("Cannot remove display device %s\n",
-                                                pci_name(temp));
-                                        pci_dev_put(temp);
-                                        continue;
-                                }
+                if (temp->hdr_type == PCI_HEADER_TYPE_BRIDGE && presence) {
+                        pci_read_config_byte(temp, PCI_BRIDGE_CONTROL, &bctl);
+                        if (bctl & PCI_BRIDGE_CTL_VGA) {
+                                err("Cannot remove display device %s\n",
+                                    pci_name(temp));
+                                pci_dev_put(temp);
+                                continue;
                         }
                 }
                 pci_remove_bus_device(temp);
+                /*
+                 * Ensure that no new Requests will be generated from
+                 * the device.
+                 */
+                if (presence) {
+                        pci_read_config_word(temp, PCI_COMMAND, &command);
+                        command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
+                        command |= PCI_COMMAND_INTX_DISABLE;
+                        pci_write_config_word(temp, PCI_COMMAND, command);
+                }
                 pci_dev_put(temp);
         }
         /*