UefiCpuPkg/CpuDxe: Put CPU to sleep during Idle events

When the MdeModulePkg gCoreEventIdleGuid event is signaled,
CpuSleep is called.  This will cause the CPU to sleep until
the next interrupt occurs.

Signed-off-by: jljusten
Reviewed-by: mdkinney
Reviewed-by: rsun3

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11842 6f19259b-4bc3-4df7-8a09-765794883524

UefiCpuPkg/CpuDxe/CpuDxe.c

@@ -1154,6 +1154,25 @@ InitInterruptDescriptorTable (
 }
 
 
+/**
+  Callback function for idle events.
+ 
+  @param  Event                 Event whose notification function is being invoked.
+  @param  Context               The pointer to the notification function's context,
+                                which is implementation-dependent.
+
+**/
+VOID
+EFIAPI
+IdleLoopEventCallback (
+  IN EFI_EVENT                Event,
+  IN VOID                     *Context
+  )
+{
+  CpuSleep ();
+}
+
+
 /**
   Initialize the state information for the CPU Architectural Protocol.
 
@@ -1173,6 +1192,7 @@ InitializeCpu (
   )
 {
   EFI_STATUS  Status;
+  EFI_EVENT   IdleLoopEvent;
 
   //
   // Make sure interrupts are disabled
@@ -1204,6 +1224,19 @@ InitializeCpu (
   //
   RefreshGcdMemoryAttributes ();
 
+  //
+  // Setup a callback for idle events
+  //
+  Status = gBS->CreateEventEx (
+                  EVT_NOTIFY_SIGNAL,
+                  TPL_NOTIFY,
+                  IdleLoopEventCallback,
+                  NULL,
+                  &gIdleLoopEventGuid,
+                  &IdleLoopEvent
+                  );
+  ASSERT_EFI_ERROR (Status);
+
   return Status;
 }
 

UefiCpuPkg/CpuDxe/CpuDxe.h

@@ -1,7 +1,7 @@
 /** @file
   CPU DXE Module.
 
-  Copyright (c) 2008 - 2010, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2008 - 2011, 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
@@ -28,6 +28,7 @@
 #include <Library/MemoryAllocationLib.h>
 #include <Library/DebugLib.h>
 #include <Library/MtrrLib.h>
+#include <Guid/IdleLoopEvent.h>
 
 //
 //

UefiCpuPkg/CpuDxe/CpuDxe.inf

@@ -2,7 +2,7 @@
 #
 #    Component description file for simple CPU driver
 #
-#  Copyright (c) 2008 - 2010, Intel Corporation. All rights reserved.<BR>
+#  Copyright (c) 2008 - 2011, 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
@@ -24,6 +24,7 @@
 
 [Packages]
   MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
   UefiCpuPkg/UefiCpuPkg.dec
 
 [LibraryClasses]
@@ -59,6 +60,9 @@
 [Protocols]
   gEfiCpuArchProtocolGuid
 
+[Guids]
+  gIdleLoopEventGuid                            ## CONSUMES ## GUID
+
 [Depex]
   TRUE