summaryrefslogtreecommitdiff
path: root/Vlv2TbltDevicePkg/PlatformPei/Stall.c
diff options
context:
space:
mode:
Diffstat (limited to 'Vlv2TbltDevicePkg/PlatformPei/Stall.c')
-rw-r--r--Vlv2TbltDevicePkg/PlatformPei/Stall.c95
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;
+}