/** @file\r
\r
Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>\r
- \r
- This program and the accompanying materials\r
- are licensed and made available under the terms and conditions of the BSD License\r
- which accompanies this distribution. The full text of the license may be found at\r
- http://opensource.org/licenses/bsd-license.php\r
+ Copyright (c) 2013, ARM Ltd. All rights reserved.\r
\r
- THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
- WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+ SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
\r
#include <Protocol/Metronome.h>\r
\r
+EFI_STATUS\r
+EFIAPI\r
+WaitForTick (\r
+ IN EFI_METRONOME_ARCH_PROTOCOL *This,\r
+ IN UINT32 TickNumber\r
+ );\r
\r
+/**\r
+ Interface structure for the Metronome Architectural Protocol.\r
+\r
+ @par Protocol Description:\r
+ This protocol provides access to a known time source in the platform to the\r
+ core. The core uses this known time source to produce core services that\r
+ require calibrated delays.\r
+\r
+ @param WaitForTick\r
+ Waits for a specified number of ticks from a known time source\r
+ in the platform. The actual time passed between entry of this\r
+ function and the first tick is between 0 and TickPeriod 100 nS\r
+ units. If you want to guarantee that at least TickPeriod time\r
+ has elapsed, wait for two ticks.\r
+\r
+ @param TickPeriod\r
+ The period of platform's known time source in 100 nS units.\r
+ This value on any platform must not exceed 200 uS. The value in this field\r
+ is a constant that must not be modified after the Metronome architectural\r
+ protocol is installed. All consumers must treat this as a read-only field.\r
+\r
+**/\r
+EFI_METRONOME_ARCH_PROTOCOL gMetronome = {\r
+ WaitForTick,\r
+ FixedPcdGet32 (PcdMetronomeTickPeriod)\r
+};\r
\r
/**\r
- The WaitForTick() function waits for the number of ticks specified by \r
- TickNumber from a known time source in the platform. If TickNumber of \r
- ticks are detected, then EFI_SUCCESS is returned. The actual time passed \r
- between entry of this function and the first tick is between 0 and \r
- TickPeriod 100 nS units. If you want to guarantee that at least TickPeriod \r
- time has elapsed, wait for two ticks. This function waits for a hardware \r
- event to determine when a tick occurs. It is possible for interrupt \r
- processing, or exception processing to interrupt the execution of the \r
- WaitForTick() function. Depending on the hardware source for the ticks, it \r
- is possible for a tick to be missed. This function cannot guarantee that \r
- ticks will not be missed. If a timeout occurs waiting for the specified \r
+ The WaitForTick() function waits for the number of ticks specified by\r
+ TickNumber from a known time source in the platform. If TickNumber of\r
+ ticks are detected, then EFI_SUCCESS is returned. The actual time passed\r
+ between entry of this function and the first tick is between 0 and\r
+ TickPeriod 100 nS units. If you want to guarantee that at least TickPeriod\r
+ time has elapsed, wait for two ticks. This function waits for a hardware\r
+ event to determine when a tick occurs. It is possible for interrupt\r
+ processing, or exception processing to interrupt the execution of the\r
+ WaitForTick() function. Depending on the hardware source for the ticks, it\r
+ is possible for a tick to be missed. This function cannot guarantee that\r
+ ticks will not be missed. If a timeout occurs waiting for the specified\r
number of ticks, then EFI_TIMEOUT is returned.\r
\r
@param This The EFI_METRONOME_ARCH_PROTOCOL instance.\r
)\r
{\r
//\r
- // Fill me in\r
+ // Compute how long to stall the CPU.\r
+ // gMetronome.TickPeriod is in 100 ns units so it needs to be divided by 10\r
+ // to get it in microseconds units.\r
//\r
- MicroSecondDelay (10 * TickNumber);\r
- return EFI_UNSUPPORTED;\r
+ MicroSecondDelay (TickNumber * gMetronome.TickPeriod / 10);\r
+ return EFI_SUCCESS;\r
}\r
\r
-\r
-\r
-/**\r
- Interface structure for the Metronome Architectural Protocol.\r
-\r
- @par Protocol Description:\r
- This protocol provides access to a known time source in the platform to the\r
- core. The core uses this known time source to produce core services that \r
- require calibrated delays. \r
-\r
- @param WaitForTick\r
- Waits for a specified number of ticks from a known time source \r
- in the platform. The actual time passed between entry of this \r
- function and the first tick is between 0 and TickPeriod 100 nS \r
- units. If you want to guarantee that at least TickPeriod time \r
- has elapsed, wait for two ticks.\r
-\r
- @param TickPeriod\r
- The period of platform's known time source in 100 nS units. \r
- This value on any platform must be at least 10 uS, and must not \r
- exceed 200 uS. The value in this field is a constant that must \r
- not be modified after the Metronome architectural protocol is \r
- installed. All consumers must treat this as a read-only field.\r
-\r
-**/\r
-EFI_METRONOME_ARCH_PROTOCOL gMetronome = {\r
- WaitForTick,\r
- 100 \r
-};\r
-\r
-\r
EFI_HANDLE gMetronomeHandle = NULL;\r
\r
-\r
-\r
/**\r
Initialize the state information for the CPU Architectural Protocol\r
\r
\r
**/\r
EFI_STATUS\r
+EFIAPI\r
MetronomeInitialize (\r
- IN EFI_HANDLE ImageHandle,\r
- IN EFI_SYSTEM_TABLE *SystemTable\r
+ IN EFI_HANDLE ImageHandle,\r
+ IN EFI_SYSTEM_TABLE *SystemTable\r
)\r
{\r
EFI_STATUS Status;\r
- \r
+\r
//\r
// Do any hardware init required to make WaitForTick () to work here.\r
//\r
\r
Status = gBS->InstallMultipleProtocolInterfaces (\r
&gMetronomeHandle,\r
- &gEfiMetronomeArchProtocolGuid, &gMetronome,\r
+ &gEfiMetronomeArchProtocolGuid,\r
+ &gMetronome,\r
NULL\r
);\r
ASSERT_EFI_ERROR (Status);\r
\r
return Status;\r
}\r
-\r
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