diff options
| author |   Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
|---|---|---|
| committer | Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
| commit | af1a266670d040d2f4083ff309d732d648afba2a (patch) | |
| tree | 2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/edk2/MdeModulePkg/Universal/Metronome/Metronome.c | |
| parent | e02cda008591317b1625707ff8e115a4841aa889 (diff) | |
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/edk2/MdeModulePkg/Universal/Metronome/Metronome.c')
| -rw-r--r-- | roms/edk2/MdeModulePkg/Universal/Metronome/Metronome.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/roms/edk2/MdeModulePkg/Universal/Metronome/Metronome.c b/roms/edk2/MdeModulePkg/Universal/Metronome/Metronome.c new file mode 100644 index 000000000..fdee1e39a --- /dev/null +++ b/roms/edk2/MdeModulePkg/Universal/Metronome/Metronome.c @@ -0,0 +1,119 @@ +/** @file
+ Produces the Metronome Architectural Protocol on top of Timer Library.
+
+ This is a generic implementation of the Metronome Architectural Protocol that
+ layers on top of an instance of the Timer Library. The Timer Library provides
+ functions for nanosecond and microsecond delays. This generic implementation
+ produces a fixed TickPeriod of 1 100ns unit, and when the WaitForTick() service
+ is called, the number of ticks passed in is converted to either nanosecond or
+ microsecond units. If the number of ticks is small, then nanoseconds are used.
+ If the number of ticks is large, then microseconds are used. This prevents
+ overflows that could occur for long delays if only nanoseconds were used and also
+ provides the greatest accuracy for small delays.
+
+Copyright (c) 2008 - 2018, Intel Corporation. All rights reserved.<BR>
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include "Metronome.h"
+
+//
+// Handle for the Metronome Architectural Protocol instance produced by this driver
+//
+EFI_HANDLE mMetronomeHandle = NULL;
+
+//
+// The Metronome Architectural Protocol instance produced by this driver
+//
+EFI_METRONOME_ARCH_PROTOCOL mMetronome = {
+ WaitForTick,
+ 1 // TickPeriod = 1*100 ns units
+};
+
+/**
+ Waits for the specified number of ticks.
+
+ This function implements EFI_METRONOME_ARCH_PROTOCOL.WaitForTick().
+ The WaitForTick() function waits for the number of ticks specified by
+ TickNumber from a known time source in the platform. If TickNumber of
+ ticks are detected, then EFI_SUCCESS is returned. The actual time passed
+ between entry of this function and the first tick is between 0 and
+ TickPeriod 100 nS units. If you want to guarantee that at least TickPeriod
+ time has elapsed, wait for two ticks. This function waits for a hardware
+ event to determine when a tick occurs. It is possible for interrupt
+ processing, or exception processing to interrupt the execution of the
+ WaitForTick() function. Depending on the hardware source for the ticks, it
+ is possible for a tick to be missed. This function cannot guarantee that
+ ticks will not be missed. If a timeout occurs waiting for the specified
+ number of ticks, then EFI_TIMEOUT is returned.
+
+ @param This The EFI_METRONOME_ARCH_PROTOCOL instance.
+ @param TickNumber Number of ticks to wait.
+
+ @retval EFI_SUCCESS The wait for the number of ticks specified by TickNumber
+ succeeded.
+ @retval EFI_TIMEOUT A timeout occurred waiting for the specified number of ticks.
+
+**/
+EFI_STATUS
+EFIAPI
+WaitForTick (
+ IN EFI_METRONOME_ARCH_PROTOCOL *This,
+ IN UINT32 TickNumber
+ )
+{
+ //
+ // Check the value of TickNumber, so a 32-bit overflow can be avoided
+ // when TickNumber of converted to nanosecond units
+ //
+ if (TickNumber < 10000000) {
+ //
+ // If TickNumber is small, then use NanoSecondDelay()
+ //
+ NanoSecondDelay (TickNumber * 100);
+ } else {
+ //
+ // If TickNumber is large, then use MicroSecondDelay()
+ //
+ MicroSecondDelay (TickNumber / 10);
+ }
+ return EFI_SUCCESS;
+}
+
+/**
+ The user Entry Point for module Metronome. The user code starts with this function.
+
+ @param[in] ImageHandle The firmware allocated handle for the EFI image.
+ @param[in] SystemTable A pointer to the EFI System Table.
+
+ @retval EFI_SUCCESS The entry point is executed successfully.
+ @retval other Some error occurs when executing this entry point.
+
+**/
+EFI_STATUS
+EFIAPI
+InstallMetronome (
+ IN EFI_HANDLE ImageHandle,
+ IN EFI_SYSTEM_TABLE *SystemTable
+ )
+{
+ EFI_STATUS Status;
+
+ //
+ // Make sure the Metronome Architectural Protocol is not already installed in the system
+ //
+ ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiMetronomeArchProtocolGuid);
+
+ //
+ // Install on a new handle
+ //
+ Status = gBS->InstallMultipleProtocolInterfaces (
+ &mMetronomeHandle,
+ &gEfiMetronomeArchProtocolGuid, &mMetronome,
+ NULL
+ );
+ ASSERT_EFI_ERROR (Status);
+
+ return Status;
+}
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