[PATCH] PcAtChipsetPkg/IsaAcpiDxe: Restore PCI attributes correctly

[Ruiyu Ni <ruiyu.ni@intel.com>]

The original code enables some BITs in PCI attributes in Start(),
but wrongly to disable these BITs in Stop().

The correct behavior is to save the original PCI attributes before
enables some BITs in Start(), and restore to original value
in Stop().

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
---
 PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.c | 44 +++++++++++++++++----------------
 PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.h |  3 ++-
 2 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.c b/PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.c
index 32381b112d..60d2fb5a5b 100644
--- a/PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.c
+++ b/PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.c
@@ -172,6 +172,7 @@ PcatIsaAcpiDriverBindingStart (
   EFI_PCI_IO_PROTOCOL  *PciIo;
   PCAT_ISA_ACPI_DEV    *PcatIsaAcpiDev;
   UINT64               Supports;
+  UINT64               OriginalAttributes;
   BOOLEAN              Enabled;
 
   Enabled = FALSE;
@@ -210,9 +211,18 @@ PcatIsaAcpiDriverBindingStart (
   if (Supports == 0 || Supports == (EFI_PCI_IO_ATTRIBUTE_ISA_IO | EFI_PCI_IO_ATTRIBUTE_ISA_IO_16)) {
     Status = EFI_UNSUPPORTED;
     goto Done;
-  }  
+  }
+
+  Status = PciIo->Attributes (
+                    PciIo,
+                    EfiPciIoAttributeOperationGet,
+                    0,
+                    &OriginalAttributes
+                    );
+  if (EFI_ERROR (Status)) {
+    goto Done;
+  }
 
-  Enabled = TRUE;
   Status = PciIo->Attributes (
                     PciIo, 
                     EfiPciIoAttributeOperationEnable, 
@@ -222,7 +232,8 @@ PcatIsaAcpiDriverBindingStart (
   if (EFI_ERROR (Status)) {
     goto Done;
   }
-  
+
+  Enabled = TRUE;
   //
   // Allocate memory for the PCAT ISA ACPI Device structure
   //
@@ -239,9 +250,10 @@ PcatIsaAcpiDriverBindingStart (
   //
   // Initialize the PCAT ISA ACPI Device structure
   //
-  PcatIsaAcpiDev->Signature = PCAT_ISA_ACPI_DEV_SIGNATURE;
-  PcatIsaAcpiDev->Handle    = Controller;
-  PcatIsaAcpiDev->PciIo     = PciIo;
+  PcatIsaAcpiDev->Signature         = PCAT_ISA_ACPI_DEV_SIGNATURE;
+  PcatIsaAcpiDev->Handle            = Controller;
+  PcatIsaAcpiDev->PciIo             = PciIo;
+  PcatIsaAcpiDev->OriginalAttribute = OriginalAttributes;
 
   //
   // Initialize PcatIsaAcpiDeviceList
@@ -274,8 +286,8 @@ Done:
     if (PciIo != NULL && Enabled) {
       PciIo->Attributes (
                PciIo, 
-               EfiPciIoAttributeOperationDisable, 
-               EFI_PCI_DEVICE_ENABLE | Supports | EFI_PCI_IO_ATTRIBUTE_ISA_MOTHERBOARD_IO,
+               EfiPciIoAttributeOperationSet, 
+               OriginalAttributes,
                NULL 
                );
     }
@@ -321,7 +333,6 @@ PcatIsaAcpiDriverBindingStop (
   EFI_STATUS             Status;
   EFI_ISA_ACPI_PROTOCOL  *IsaAcpi;
   PCAT_ISA_ACPI_DEV      *PcatIsaAcpiDev;
-  UINT64                 Supports;
   
   //
   // Get the ISA ACPI Protocol Interface
@@ -348,23 +359,14 @@ PcatIsaAcpiDriverBindingStop (
   //
   Status = PcatIsaAcpiDev->PciIo->Attributes (
                                     PcatIsaAcpiDev->PciIo,
-                                    EfiPciIoAttributeOperationSupported,
-                                    0,
-                                    &Supports
+                                    EfiPciIoAttributeOperationSet,
+                                    PcatIsaAcpiDev->OriginalAttribute,
+                                    0
                                     );
   if (EFI_ERROR (Status)) {
     return Status;
   }
 
-  Supports &= (UINT64) (EFI_PCI_IO_ATTRIBUTE_ISA_IO | EFI_PCI_IO_ATTRIBUTE_ISA_IO_16);
-
-  PcatIsaAcpiDev->PciIo->Attributes (
-                           PcatIsaAcpiDev->PciIo, 
-                           EfiPciIoAttributeOperationDisable, 
-                           EFI_PCI_DEVICE_ENABLE | Supports | EFI_PCI_IO_ATTRIBUTE_ISA_MOTHERBOARD_IO,
-                           NULL 
-                           );
- 
   //
   // Uninstall protocol interface: EFI_ISA_ACPI_PROTOCOL
   //
diff --git a/PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.h b/PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.h
index 0671127644..3ad3a3f313 100644
--- a/PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.h
+++ b/PcAtChipsetPkg/IsaAcpiDxe/PcatIsaAcpi.h
@@ -1,7 +1,7 @@
 /** @file
   EFI PCAT ISA ACPI Driver for a Generic PC Platform
 
-Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials                          
 are licensed and made available under the terms and conditions of the BSD License         
 which accompanies this distribution.  The full text of the license may be found at        
@@ -43,6 +43,7 @@ typedef struct {
   EFI_HANDLE             Handle;    
   EFI_ISA_ACPI_PROTOCOL  IsaAcpi;
   EFI_PCI_IO_PROTOCOL    *PciIo;
+  UINT64                 OriginalAttribute;
 } PCAT_ISA_ACPI_DEV;
 
 #define PCAT_ISA_ACPI_DEV_FROM_THIS(a) BASE_CR(a, PCAT_ISA_ACPI_DEV, IsaAcpi)
-- 
2.12.2.windows.2