alder_lake_bios/Intel/AlderLake/AlderLakeChipsetPkg/Library/SmmHeciLib/HeciHpet.c

/** @file
  HPET timer definitions for HECI driver

@copyright
  INTEL CONFIDENTIAL
  Copyright 2006 - 2020 Intel Corporation.

  The source code contained or described herein and all documents related to the
  source code ("Material") are owned by Intel Corporation or its suppliers or
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  confidential information of Intel Corporation and its suppliers and licensors,
  and is protected by worldwide copyright and trade secret laws and treaty
  provisions. No part of the Material may be used, copied, reproduced, modified,
  published, uploaded, posted, transmitted, distributed, or disclosed in any way
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  No license under any patent, copyright, trade secret or other intellectual
  property right is granted to or conferred upon you by disclosure or delivery
  of the Materials, either expressly, by implication, inducement, estoppel or
  otherwise. Any license under such intellectual property rights must be
  express and approved by Intel in writing.

  Unless otherwise agreed by Intel in writing, you may not remove or alter
  this notice or any other notice embedded in Materials by Intel or
  Intel's suppliers or licensors in any way.

  This file contains an 'Intel Peripheral Driver' and is uniquely identified as
  "Intel Reference Module" and is licensed for Intel CPUs and chipsets under
  the terms of your license agreement with Intel or your vendor. This file may
  be modified by the user, subject to additional terms of the license agreement.

@par Specification Reference:
**/

#include <Base.h>
#include <Uefi.h>
#include <Library/IoLib.h>
#include <Library/PchCycleDecodingLib.h>
#include <Register/HeciRegs.h>
#include "HeciCore.h"
#include "HeciHpet.h"

GLOBAL_REMOVE_IF_UNREFERENCED UINT32 mHpetBaseAddr = 0;

/**
  Used for calculating timeouts

  @param[in] Start                Snapshot of the HPET timer
  @param[in] End                  Calculated time when timeout period will be done
  @param[in] Time                 Timeout period in microseconds

**/
VOID
SmmHeciStartTimer (
  OUT UINT32 *Start,
  OUT UINT32 *End,
  IN  UINT32 Time
  )
{
  UINT32 HpetTimer;

  ///
  /// Get the High Precision Event Timer base address
  ///
  if (mHpetBaseAddr == 0) {
    PchHpetBaseGet (&HpetTimer);
    mHpetBaseAddr = HpetTimer;
  } else {
    HpetTimer = mHpetBaseAddr;
  }

  ///
  /// Start the timer so it is up and running
  ///
  MmioOr32 ((UINTN)HpetTimer + HPET_GEN_CONFIG, HPET_START);

  ///
  /// Read current timer value into start time from HPET
  ///
  *Start = MmioRead32 ((UINTN)HpetTimer + HPET_MAIN_COUNTER);

  ///
  /// Convert microseconds into 41.6 ns timer ticks and compute end time
  ///
  *End = *Start + Time * HPET_TICKS_PER_MICRO;
}


/**
  Used to determine if a timeout has occured.

  @param[in] Start                Snapshot of the HPET timer when the timeout period started.
  @param[in] End                  Calculated time when timeout period will be done.
  @param[in] HpetTimer            The value of High Precision Event Timer

  @retval TRUE                    Timeout occured.
  @retval FALSE                   Timeout has not occured yet.
**/
BOOLEAN
IsHeciTimeout (
  IN UINT32 Start,
  IN UINT32 End
  )
{
  UINT32 Current;
  UINT32 HpetTimer;

  ///
  /// Get the High Precision Event Timer base address
  ///
  if (mHpetBaseAddr == 0) {
    PchHpetBaseGet (&HpetTimer);
    mHpetBaseAddr = HpetTimer;
  } else {
    HpetTimer = mHpetBaseAddr;
  }

  ///
  /// Read HPET and assign the value as the current time.
  ///
  Current = MmioRead32 ((UINTN)HpetTimer + HPET_MAIN_COUNTER);

  ///
  /// Test basic case (no overflow)
  ///
  if ((Start < End) && (End <= Current)) {
    return TRUE;
  }
  ///
  /// Test basic start/end conditions with overflowed timer
  ///
  if ((Start < End) && (Current < Start)) {
    return TRUE;
  }
  ///
  /// Test for overflowed start/end condition
  ///
  if ((Start > End) && ((Current < Start) && (Current > End))) {
    return TRUE;
  }
  ///
  /// Catch corner case of broken arguments
  ///
  if (Start == End) {
    return TRUE;
  }
  ///
  /// Else, we have not yet timed out
  ///
  return FALSE;
}