EDK2 carries an interesting quirk which dates back to the EFI 1.02 days,
where each protocol that is installed onto a handle during the execution
of a DXE driver's entrypoint is connected immediately (in the UEFI driver
model sense) after the entry point returns.

This means that, depending on the order that these drivers happen to end
up being dispatched, we may enter the BDS phase with the device's driver
stack fully connected, even if the device in question is not being used
to boot the machine.

Given the substantial delays that this might incur, let's work around
this 'feature' by deferring the registration of the network and eMMC
controllers to an EndOfDxe event handler.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
---
 Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c   | 37 ++++++++++++++------
 Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf |  1 +
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c
index b6e2789cb9d2..09200a918009 100644
--- a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c
+++ b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c
@@ -301,6 +301,28 @@ InstallAcpiTables (
   }
 }
 
+STATIC
+VOID
+EFIAPI
+RegisterDevices (
+  EFI_EVENT           Event,
+  VOID                *Context
+  )
+{
+  EFI_HANDLE                      Handle;
+  EFI_STATUS                      Status;
+
+  Handle = NULL;
+  Status = RegisterDevice (&gNetsecNonDiscoverableDeviceGuid, mNetsecDesc,
+             &Handle);
+  ASSERT_EFI_ERROR (Status);
+
+  if (mHiiSettings->EnableEmmc == EMMC_ENABLED) {
+    Status = RegisterEmmc ();
+    ASSERT_EFI_ERROR (Status);
+  }
+}
+
 EFI_STATUS
 EFIAPI
 PlatformDxeEntryPoint (
@@ -315,6 +337,7 @@ PlatformDxeEntryPoint (
   EFI_ACPI_DESCRIPTION_HEADER     *Ssdt;
   UINTN                           SsdtSize;
   UINTN                           Index;
+  EFI_EVENT                       EndOfDxeEvent;
 
   mHiiSettingsVal = PcdGet64 (PcdPlatformSettings);
   mHiiSettings = (SYNQUACER_PLATFORM_VARSTORE_DATA *)&mHiiSettingsVal;
@@ -344,11 +367,6 @@ PlatformDxeEntryPoint (
     }
   }
 
-  Handle = NULL;
-  Status = RegisterDevice (&gNetsecNonDiscoverableDeviceGuid, mNetsecDesc,
-             &Handle);
-  ASSERT_EFI_ERROR (Status);
-
   Handle = NULL;
   Status = RegisterDevice (&gSynQuacerNonDiscoverableRuntimeI2cMasterGuid,
              mI2c0Desc, &Handle);
@@ -387,11 +405,6 @@ PlatformDxeEntryPoint (
   Status = EnableSettingsForm ();
   ASSERT_EFI_ERROR (Status);
 
-  if (mHiiSettings->EnableEmmc == EMMC_ENABLED) {
-    Status = RegisterEmmc ();
-    ASSERT_EFI_ERROR (Status);
-  }
-
   if (mHiiSettings->AcpiPref == ACPIPREF_ACPI) {
     //
     // Load the SSDT tables from a raw section in this FFS file.
@@ -431,5 +444,9 @@ PlatformDxeEntryPoint (
     }
   }
 
+  Status = gBS->CreateEventEx (EVT_NOTIFY_SIGNAL, TPL_NOTIFY, RegisterDevices,
+                  NULL, &gEfiEndOfDxeEventGroupGuid, &EndOfDxeEvent);
+  ASSERT_EFI_ERROR (Status);
+
   return EFI_SUCCESS;
 }
diff --git a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf
index 57f2d071c14e..157f914ea85d 100644
--- a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf
+++ b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf
@@ -57,6 +57,7 @@ [LibraryClasses]
 [Guids]
   g96BoardsI2c0MasterGuid
   gEdkiiPlatformHasAcpiGuid
+  gEfiEndOfDxeEventGroupGuid
   gEfiHiiPlatformSetupFormsetGuid
   gFdtTableGuid
   gNetsecNonDiscoverableDeviceGuid
-- 
2.17.1


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