Omap35xxPkg/InterruptDxe: replace CPU Arch Protocol depex with notify

In a later patch, we'll modify the depex of
"ArmPkg/Drivers/CpuDxe/CpuDxe.inf" (currently "AFTER gArmGicDxeFileGuid")
to "gHardwareInterruptProtocolGuid OR gHardwareInterrupt2ProtocolGuid".

Considering platforms that include "ArmPkg/Drivers/CpuDxe/CpuDxe.inf",
there are two classes:

(1) The platform gets its gHardwareInterruptProtocolGuid or
    gHardwareInterrupt2ProtocolGuid instance from
    "ArmPkg/Drivers/ArmGic/ArmGicDxe.inf". For such platforms, the
    upcoming CpuDxe change is not a problem, because commit 61a7b0ec63
    made ArmGicDxe wait for the CPU Arch Protocol with a protocol notify.

(2) The platform gets its hardware interrupt protocol(s) from a different
    driver that has a hard depex on the CPU Arch Protocol. The upcoming
    CpuDxe change would lead to a loop in the DXE dispatch order.

In the edk2 tree, only "BeagleBoardPkg/BeagleBoardPkg.dsc" falls in class
(2), and the driver in question is "Omap35xxPkg/InterruptDxe". Port (most
of) commit 61a7b0ec63 to it.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Supreeth Venkatesh <Supreeth.Venkatesh@arm.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

Omap35xxPkg/InterruptDxe/HardwareInterrupt.c

@@ -296,6 +296,54 @@ EFI_HARDWARE_INTERRUPT_PROTOCOL gHardwareInterruptProtocol = {
   EndOfInterrupt
 };
 
+STATIC VOID *mCpuArchProtocolNotifyEventRegistration;
+
+STATIC
+VOID
+EFIAPI
+CpuArchEventProtocolNotify (
+  IN  EFI_EVENT       Event,
+  IN  VOID            *Context
+  )
+{
+  EFI_CPU_ARCH_PROTOCOL   *Cpu;
+  EFI_STATUS              Status;
+
+  //
+  // Get the CPU protocol that this driver requires.
+  //
+  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **)&Cpu);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "%a: gBS->LocateProtocol() - %r\n", __FUNCTION__,
+      Status));
+    ASSERT (FALSE);
+    return;
+  }
+
+  //
+  // Unregister the default exception handler.
+  //
+  Status = Cpu->RegisterInterruptHandler (Cpu, EXCEPT_ARM_IRQ, NULL);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "%a: Cpu->RegisterInterruptHandler() - %r\n",
+      __FUNCTION__, Status));
+    ASSERT (FALSE);
+    return;
+  }
+
+  //
+  // Register to receive interrupts
+  //
+  Status = Cpu->RegisterInterruptHandler (Cpu, EXCEPT_ARM_IRQ,
+                  IrqInterruptHandler);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "%a: Cpu->RegisterInterruptHandler() - %r\n",
+      __FUNCTION__, Status));
+    ASSERT (FALSE);
+    return;
+  }
+}
+
 /**
   Initialize the state information for the CPU Architectural Protocol
 
@@ -314,7 +362,7 @@ InterruptDxeInitialize (
   )
 {
   EFI_STATUS  Status;
-  EFI_CPU_ARCH_PROTOCOL   *Cpu;
+  EFI_EVENT   CpuArchEvent;
 
   // Make sure the Interrupt Controller Protocol is not already installed in the system.
   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gHardwareInterruptProtocolGuid);
@@ -331,26 +379,23 @@ InterruptDxeInitialize (
   ASSERT_EFI_ERROR(Status);
 
   //
-  // Get the CPU protocol that this driver requires.
+  // Install the interrupt handler as soon as the CPU arch protocol appears.
   //
-  Status = gBS->LocateProtocol(&gEfiCpuArchProtocolGuid, NULL, (VOID **)&Cpu);
-  ASSERT_EFI_ERROR(Status);
-
-  //
-  // Unregister the default exception handler.
-  //
-  Status = Cpu->RegisterInterruptHandler(Cpu, EXCEPT_ARM_IRQ, NULL);
-  ASSERT_EFI_ERROR(Status);
-
-  //
-  // Register to receive interrupts
-  //
-  Status = Cpu->RegisterInterruptHandler(Cpu, EXCEPT_ARM_IRQ, IrqInterruptHandler);
-  ASSERT_EFI_ERROR(Status);
+  CpuArchEvent = EfiCreateProtocolNotifyEvent (
+                   &gEfiCpuArchProtocolGuid,
+                   TPL_CALLBACK,
+                   CpuArchEventProtocolNotify,
+                   NULL,
+                   &mCpuArchProtocolNotifyEventRegistration
+                   );
+  ASSERT (CpuArchEvent != NULL);
 
   // Register for an ExitBootServicesEvent
   Status = gBS->CreateEvent(EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent);
-  ASSERT_EFI_ERROR(Status);
+  if (EFI_ERROR (Status)) {
+    ASSERT_EFI_ERROR (Status);
+    gBS->CloseEvent (CpuArchEvent);
+  }
 
   return Status;
 }

Omap35xxPkg/InterruptDxe/InterruptDxe.inf

@@ -44,11 +44,11 @@
   ArmLib
 
 [Protocols]
-  gHardwareInterruptProtocolGuid
-  gEfiCpuArchProtocolGuid
+  gHardwareInterruptProtocolGuid  ## PRODUCES
+  gEfiCpuArchProtocolGuid         ## CONSUMES ## NOTIFY
 
 [FixedPcd.common]
   gEmbeddedTokenSpaceGuid.PcdInterruptBaseAddress
 
 [Depex]
-  gEfiCpuArchProtocolGuid
+  TRUE