1 files changed, 95 insertions, 0 deletions
diff --git a/Vlv2TbltDevicePkg/PlatformPei/Stall.c b/Vlv2TbltDevicePkg/PlatformPei/Stall.c
new file mode 100644
index 0000000000..8c2ab99f1c
--- /dev/null
+++ b/Vlv2TbltDevicePkg/PlatformPei/Stall.c
@@ -0,0 +1,95 @@
+/** @file
+
+  Copyright (c) 2004  - 2014, 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 that accompanies this distribution.  
+  The full text of the license may be found at                                     
+  http://opensource.org/licenses/bsd-license.php.                                  
+                                                                                   
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,            
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.    
+                                                                                   
+
+
+Module Name:
+
+  Stall.c
+
+Abstract:
+
+  Produce Stall Ppi.
+
+--*/
+
+
+#include "CommonHeader.h"
+#include "PlatformBaseAddresses.h"
+#include "PchRegs.h"
+
+/**
+  Waits for at least the given number of microseconds.
+
+  @param PeiServices     General purpose services available to every PEIM.
+  @param This            PPI instance structure.
+  @param Microseconds    Desired length of time to wait.
+
+  @retval EFI_SUCCESS    If the desired amount of time was passed.
+
+**/
+EFI_STATUS
+EFIAPI
+Stall (
+  IN CONST EFI_PEI_SERVICES   **PeiServices,
+  IN CONST EFI_PEI_STALL_PPI      *This,
+  IN UINTN              Microseconds
+  )
+{
+  UINTN   Ticks;
+  UINTN   Counts;
+  UINT32  CurrentTick;
+  UINT32  OriginalTick;
+  UINT32  RemainingTick;
+
+  if (Microseconds == 0) {
+    return EFI_SUCCESS;
+  }
+
+  OriginalTick = IoRead32 (ACPI_BASE_ADDRESS + R_PCH_ACPI_PM1_TMR);
+  OriginalTick &= (V_PCH_ACPI_PM1_TMR_MAX_VAL - 1);
+  CurrentTick = OriginalTick;
+
+  //
+  // The timer frequency is 3.579545MHz, so 1 ms corresponds to 3.58 clocks
+  //
+  Ticks = Microseconds * 358 / 100 + OriginalTick + 1;
+
+  //
+  // The loops needed for timer overflow
+  //
+  Counts = (UINTN)RShiftU64((UINT64)Ticks, 24);
+
+  //
+  // Remaining clocks within one loop
+  //
+  RemainingTick = Ticks & 0xFFFFFF;
+
+  //
+  // Do not intend to use TMROF_STS bit of register PM1_STS, because this add extra
+  // one I/O operation, and may generate SMI
+  //
+  while (Counts != 0) {
+    CurrentTick = IoRead32 (ACPI_BASE_ADDRESS + R_PCH_ACPI_PM1_TMR) & B_PCH_ACPI_PM1_TMR_VAL;
+    if (CurrentTick <= OriginalTick) {
+      Counts--;
+    }
+    OriginalTick = CurrentTick;
+  }
+
+  while ((RemainingTick > CurrentTick) && (OriginalTick <= CurrentTick)) {
+    OriginalTick  = CurrentTick;
+    CurrentTick   = IoRead32 (ACPI_BASE_ADDRESS + R_PCH_ACPI_PM1_TMR) & B_PCH_ACPI_PM1_TMR_VAL;
+  }
+
+  return EFI_SUCCESS;
+}