[DNM] MdeModulePkg: PciBusDxe: Drop RemoveRejectedPciDevices()

There is an assumption in `IsPciDeviceRejected()` (at least for I/O) that a BAR with all read-write bits set is invalid. However, this is not the case: when a resource is size-aligned down from the top, this may also be the case. This code causes the rejection of the iGPU (and therefore, display) in some cases with the UefiPayloadPkg, when the coreboot ESOURCE_ALLOCATION_TOP_DOWN config is enabled. It remains to be seen whether this code addresses some other issue. Signed-off-by: Benjamin Doron <[email protected]>
Dasharo · Jun 14, 2024 · 6a6d410 · 6a6d410
1 parent 9756808
commit 6a6d410
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diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
@@ -2525,11 +2525,6 @@ PciEnumeratorLight (
 
     if (!EFI_ERROR (Status)) {
 
-      //
-      // Remove those PCI devices which are rejected when full enumeration
-      //
-      RemoveRejectedPciDevices (RootBridgeDev->Handle, RootBridgeDev);
-
       if (!PcdGetBool (PcdPciDisableBusEnumeration)) {
         //
         // Process option rom light
@@ -2652,117 +2647,6 @@ StartManagingRootBridge (
 
 }
 
-/**
-  This routine can be used to check whether a PCI device should be rejected when light enumeration.
-
-  @param PciIoDevice  Pci device instance.
-
-  @retval TRUE      This device should be rejected.
-  @retval FALSE     This device shouldn't be rejected.
-
-**/
-BOOLEAN
-IsPciDeviceRejected (
-  IN PCI_IO_DEVICE *PciIoDevice
-  )
-{
-  EFI_STATUS  Status;
-  UINT32      TestValue;
-  UINT32      OldValue;
-  UINT32      Mask;
-  UINT8       BarOffset;
-
-  //
-  // PPB should be skip!
-  //
-  if (IS_PCI_BRIDGE (&PciIoDevice->Pci)) {
-    return FALSE;
-  }
-
-  if (IS_CARDBUS_BRIDGE (&PciIoDevice->Pci)) {
-    //
-    // Only test base registers for P2C
-    //
-    for (BarOffset = 0x1C; BarOffset <= 0x38; BarOffset += 2 * sizeof (UINT32)) {
-
-      Mask    = (BarOffset < 0x2C) ? 0xFFFFF000 : 0xFFFFFFFC;
-      Status  = BarExisted (PciIoDevice, BarOffset, &TestValue, &OldValue);
-      if (EFI_ERROR (Status)) {
-        continue;
-      }
-
-      TestValue = TestValue & Mask;
-      if ((TestValue != 0) && (TestValue == (OldValue & Mask))) {
-        //
-        // The bar isn't programed, so it should be rejected
-        //
-        return TRUE;
-      }
-    }
-
-    return FALSE;
-  }
-
-  for (BarOffset = 0x14; BarOffset <= 0x24; BarOffset += sizeof (UINT32)) {
-    //
-    // Test PCI devices
-    //
-    Status = BarExisted (PciIoDevice, BarOffset, &TestValue, &OldValue);
-    if (EFI_ERROR (Status)) {
-      continue;
-    }
-
-    if ((TestValue & 0x01) != 0) {
-
-      //
-      // IO Bar
-      //
-      Mask      = 0xFFFFFFFC;
-      TestValue = TestValue & Mask;
-      if ((TestValue != 0) && (TestValue == (OldValue & Mask))) {
-        return TRUE;
-      }
-
-    } else {
-
-      //
-      // Mem Bar
-      //
-      Mask      = 0xFFFFFFF0;
-      TestValue = TestValue & Mask;
-
-      if ((TestValue & 0x07) == 0x04) {
-
-        //
-        // Mem64 or PMem64
-        //
-        BarOffset += sizeof (UINT32);
-        if ((TestValue != 0) && (TestValue == (OldValue & Mask))) {
-
-          //
-          // Test its high 32-Bit BAR
-          //
-          Status = BarExisted (PciIoDevice, BarOffset, &TestValue, &OldValue);
-          if (TestValue == OldValue) {
-            return TRUE;
-          }
-        }
-
-      } else {
-
-        //
-        // Mem32 or PMem32
-        //
-        if ((TestValue != 0) && (TestValue == (OldValue & Mask))) {
-          return TRUE;
-        }
-      }
-    }
-  }
-
-  return FALSE;
-}
-
 /**
   Reset all bus number from specific bridge.
 

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.h
@@ -427,20 +427,6 @@ StartManagingRootBridge (
   IN PCI_IO_DEVICE *RootBridgeDev
   );
 
-/**
-  This routine can be used to check whether a PCI device should be rejected when light enumeration.
-
-  @param PciIoDevice  Pci device instance.
-
-  @retval TRUE      This device should be rejected.
-  @retval FALSE     This device shouldn't be rejected.
-
-**/
-BOOLEAN
-IsPciDeviceRejected (
-  IN PCI_IO_DEVICE *PciIoDevice
-  );
-
 /**
   Reset all bus number from specific bridge.
 

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
@@ -138,67 +138,6 @@ GetBackPcCardBar (
   }
 }
 
-/**
-  Remove rejected pci device from specific root bridge
-  handle.
-
-  @param RootBridgeHandle  Specific parent root bridge handle.
-  @param Bridge            Bridge device instance.
-
-**/
-VOID
-RemoveRejectedPciDevices (
-  IN EFI_HANDLE        RootBridgeHandle,
-  IN PCI_IO_DEVICE     *Bridge
-  )
-{
-  PCI_IO_DEVICE   *Temp;
-  LIST_ENTRY      *CurrentLink;
-  LIST_ENTRY      *LastLink;
-
-  if (!FeaturePcdGet (PcdPciBusHotplugDeviceSupport)) {
-    return;
-  }
-
-  CurrentLink = Bridge->ChildList.ForwardLink;
-
-  while (CurrentLink != NULL && CurrentLink != &Bridge->ChildList) {
-
-    Temp = PCI_IO_DEVICE_FROM_LINK (CurrentLink);
-
-    if (IS_PCI_BRIDGE (&Temp->Pci)) {
-      //
-      // Remove rejected devices recusively
-      //
-      RemoveRejectedPciDevices (RootBridgeHandle, Temp);
-    } else {
-      //
-      // Skip rejection for all PPBs, while detect rejection for others
-      //
-      if (IsPciDeviceRejected (Temp)) {
-
-        //
-        // For P2C, remove all devices on it
-        //
-        if (!IsListEmpty (&Temp->ChildList)) {
-          RemoveAllPciDeviceOnBridge (RootBridgeHandle, Temp);
-        }
-
-        //
-        // Finally remove itself
-        //
-        LastLink = CurrentLink->BackLink;
-        RemoveEntryList (CurrentLink);
-        FreePciDevice (Temp);
-
-        CurrentLink = LastLink;
-      }
-    }
-
-    CurrentLink = CurrentLink->ForwardLink;
-  }
-}
-
 /**
   Dump the resourc map of the bridge device.
 

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.h
@@ -36,20 +36,6 @@ GetBackPcCardBar (
   IN  PCI_IO_DEVICE                  *PciIoDevice
   );
 
-/**
-  Remove rejected pci device from specific root bridge
-  handle.
-
-  @param RootBridgeHandle  Specific parent root bridge handle.
-  @param Bridge            Bridge device instance.
-
-**/
-VOID
-RemoveRejectedPciDevices (
-  IN EFI_HANDLE        RootBridgeHandle,
-  IN PCI_IO_DEVICE     *Bridge
-  );
-
 /**
   Submits the I/O and memory resource requirements for the specified PCI Host Bridge.