/** @file
  The PEI Library Implements OcWdt Support.

Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Library/DebugLib.h>
#include <Library/PeiServicesLib.h>
#include <Ppi/Wdt.h>
#include <Library/PchWdtCommonLib.h>
#include <PchAccess.h>
#include <Library/PchCycleDecodingLib.h>
#include <Library/IoLib.h>

static WDT_PPI mWdtPpi = {
  WdtReloadAndStart,
  WdtCheckStatus,
  WdtDisable,
  WdtAllowKnownReset,
  IsWdtRequired,
  IsWdtEnabled
};

static EFI_PEI_PPI_DESCRIPTOR  mInstallWdtPpi = {
  (EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
  &gWdtPpiGuid,
  &mWdtPpi
};

/**
  Reads PCH registers to check if platform wakes from S3/S4

  @retval TRUE                    if platfrom wakes from S3/S4
  @retval FALSE                   otherwise
**/
BOOLEAN
IsWakeFromS3S4 (
  VOID
  )
{
  UINT16  ABase;
  UINT16  SleepType;

  PchAcpiBaseGet (&ABase);

  if (IoRead16 (ABase + R_PCH_ACPI_PM1_STS) & B_PCH_ACPI_PM1_STS_WAK) {
    SleepType = IoRead16 (ABase + R_PCH_ACPI_PM1_CNT) & B_PCH_ACPI_PM1_CNT_SLP_TYP;
    if ((SleepType == V_PCH_ACPI_PM1_CNT_S3) || (SleepType == V_PCH_ACPI_PM1_CNT_S4)) {
      return TRUE;
    }
  }

  return FALSE;
}

/**
  Check for unexpected reset.
  If there was an unexpected reset, enforces WDT expiration.
**/
VOID
OcWdtResetCheck (
  VOID
  )
{
  UINT32      Readback;

  Readback = IoRead32 (WdtGetAddress ());

  DEBUG ((DEBUG_ERROR, "(WDT) OcWdtResetCheck\n"));

  ///
  /// If there was a WDT expiration, set Failure Status and clear timeout status bits
  /// Timeout status bits are cleared by writing '1'
  ///
  if (Readback & (B_PCH_OC_WDT_CTL_ICCSURV_STS | B_PCH_OC_WDT_CTL_NO_ICCSURV_STS)) {
    DEBUG ((DEBUG_ERROR, "(WDT) Expiration detected.\n", Readback));
    Readback |= B_PCH_OC_WDT_CTL_FAILURE_STS;
    Readback |= (B_PCH_OC_WDT_CTL_ICCSURV_STS | B_PCH_OC_WDT_CTL_NO_ICCSURV_STS);
    Readback &= ~(B_PCH_OC_WDT_CTL_UNXP_RESET_STS);
  } else {
    ///
    /// If there was unexpected reset but no WDT expiration and no resume from S3/S4,
    /// clear unexpected reset status and enforce expiration. This is to inform Firmware
    /// which has no access to unexpected reset status bit, that something went wrong.
    ///
    if ((Readback & B_PCH_OC_WDT_CTL_UNXP_RESET_STS) && !IsWakeFromS3S4 ()) {
#ifndef MDEPKG_NDEBUG
      DEBUG ((DEBUG_ERROR, "(WDT) Unexpected reset detected and ignored.\n"));
      Readback &= ~(B_PCH_OC_WDT_CTL_FAILURE_STS | B_PCH_OC_WDT_CTL_UNXP_RESET_STS);
      Readback |= (B_PCH_OC_WDT_CTL_ICCSURV_STS | B_PCH_OC_WDT_CTL_NO_ICCSURV_STS);
#else
      DEBUG ((DEBUG_ERROR, "(WDT) Unexpected reset detected. Enforcing Wdt expiration.\n"));
      WdtReloadAndStart (1);
      ///
      /// wait for reboot caused by WDT expiration
      ///
      CpuDeadLoop ();
#endif
    } else {
      ///
      /// No WDT expiration and no unexpected reset - clear Failure status
      ///
      DEBUG ((DEBUG_INFO, "(WDT) Status OK.\n", Readback));
      Readback &= ~(B_PCH_OC_WDT_CTL_FAILURE_STS);
      Readback |= (B_PCH_OC_WDT_CTL_ICCSURV_STS | B_PCH_OC_WDT_CTL_NO_ICCSURV_STS);
    }
  }

  IoWrite32 (WdtGetAddress (), Readback);
}

/**
  This function install WDT PPI

  @retval EFI_STATUS  Results of the installation of the WDT PPI
**/
EFI_STATUS
EFIAPI
OcWdtInit (
  VOID
  )
{
  EFI_STATUS  Status;

  Status = PeiServicesInstallPpi (&mInstallWdtPpi);
  ASSERT_EFI_ERROR (Status);

  return Status;
}