/** @file

  Copyright (c) 2017, Linaro, Ltd. All rights reserved.<BR>

  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which 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.

**/

#include <PiDxe.h>
#include <Library/DebugLib.h>
#include <Library/IoLib.h>
#include <Library/RealTimeClockLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>
#include <Library/UefiRuntimeLib.h>
#include <Protocol/I2cMaster.h>

#define SLAVE_ADDRESS             (FixedPcdGet8 (PcdI2cSlaveAddress))
#define PCF8563_DATA_REG_OFFSET   0x2

#define PCF8563_SECONDS_MASK      0x7f
#define PCF8563_MINUTES_MASK      0x7f
#define PCF8563_HOURS_MASK        0x3f
#define PCF8563_DAYS_MASK         0x3f
#define PCF8563_WEEKDAYS_MASK     0x07
#define PCF8563_MONTHS_MASK       0x1f
#define PCF8563_CENTURY_MASK      0x80

//
// The PCF8563 has a 'century' flag, which means it could theoretically span
// 200 years. However, it treats all years divisible by 4 as leap years,
// including the years 1900 and 2100 (which are not leap years), so the only
// sane base year is 2000 (which was a leap year).
//
#define EPOCH_BASE                2000

STATIC EFI_HANDLE                 mI2cMasterHandle;
STATIC VOID                       *mI2cMasterEventRegistration;
STATIC EFI_I2C_MASTER_PROTOCOL    *mI2cMaster;
STATIC EFI_EVENT                  mRtcVirtualAddrChangeEvent;

#pragma pack(1)
typedef struct {
  UINT8                           VL_seconds;
  UINT8                           Minutes;
  UINT8                           Hours;
  UINT8                           Days;
  UINT8                           Weekdays;
  UINT8                           Century_months;
  UINT8                           Years;
} RTC_DATETIME;

typedef struct {
  UINT8                           Reg;
  RTC_DATETIME                    DateTime;
} RTC_SET_DATETIME_PACKET;
#pragma pack()

typedef struct {
  UINTN                           OperationCount;
  EFI_I2C_OPERATION               SetAddressOp;
  EFI_I2C_OPERATION               GetDateTimeOp;
} RTC_GET_I2C_REQUEST;

typedef EFI_I2C_REQUEST_PACKET    RTC_SET_I2C_REQUEST;
/**
  Returns the current time and date information, and the time-keeping
  capabilities of the hardware platform.

  @param  Time                  A pointer to storage to receive a snapshot of
                                the current time.
  @param  Capabilities          An optional pointer to a buffer to receive the
                                real time clock device's capabilities.

  @retval EFI_SUCCESS           The operation completed successfully.
  @retval EFI_INVALID_PARAMETER Time is NULL.
  @retval EFI_DEVICE_ERROR      The time could not be retrieved due to hardware
                                error.

**/
EFI_STATUS
EFIAPI
LibGetTime (
  OUT EFI_TIME                *Time,
  OUT EFI_TIME_CAPABILITIES   *Capabilities
  )
{
  RTC_GET_I2C_REQUEST         Op;
  RTC_DATETIME                DateTime;
  EFI_STATUS                  Status;
  UINT8                       Reg;

  if (Time == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (mI2cMaster == NULL) {
    return EFI_DEVICE_ERROR;
  }

  Reg = PCF8563_DATA_REG_OFFSET;

  Op.OperationCount = 2;

  Op.SetAddressOp.Flags = 0;
  Op.SetAddressOp.LengthInBytes = 1;
  Op.SetAddressOp.Buffer = &Reg;

  Op.GetDateTimeOp.Flags = I2C_FLAG_READ;
  Op.GetDateTimeOp.LengthInBytes = sizeof (RTC_DATETIME);
  Op.GetDateTimeOp.Buffer = (VOID *)&DateTime;

  Status = mI2cMaster->StartRequest (mI2cMaster, SLAVE_ADDRESS,
                         (VOID *)&Op, NULL, NULL);
  if (EFI_ERROR (Status)) {
    return EFI_DEVICE_ERROR;
  }

  Time->Second  = BcdToDecimal8 (DateTime.VL_seconds & PCF8563_SECONDS_MASK);
  Time->Minute  = BcdToDecimal8 (DateTime.Minutes & PCF8563_MINUTES_MASK);
  Time->Hour    = BcdToDecimal8 (DateTime.Hours & PCF8563_HOURS_MASK);
  Time->Day     = BcdToDecimal8 (DateTime.Days & PCF8563_DAYS_MASK);
  Time->Month   = BcdToDecimal8 (DateTime.Century_months & PCF8563_MONTHS_MASK);
  Time->Year    = BcdToDecimal8 (DateTime.Years) + EPOCH_BASE;

  if (DateTime.Century_months & PCF8563_CENTURY_MASK) {
    Time->Year += 100;
  }

  if (Capabilities != NULL) {
    Capabilities->Resolution = 1;
    Capabilities->Accuracy = 0;
    Capabilities->SetsToZero = TRUE;
  }
  return EFI_SUCCESS;
}


/**
  Sets the current local time and date information.

  @param  Time                  A pointer to the current time.

  @retval EFI_SUCCESS           The operation completed successfully.
  @retval EFI_INVALID_PARAMETER A time field is out of range.
  @retval EFI_DEVICE_ERROR      The time could not be set due due to hardware
                                error.

**/
EFI_STATUS
EFIAPI
LibSetTime (
  IN EFI_TIME                *Time
  )
{
  RTC_SET_I2C_REQUEST         Op;
  RTC_SET_DATETIME_PACKET     Packet;
  EFI_STATUS                  Status;

  if (mI2cMaster == NULL) {
    return EFI_DEVICE_ERROR;
  }

  Packet.DateTime.VL_seconds          = DecimalToBcd8 (Time->Second);
  Packet.DateTime.Minutes             = DecimalToBcd8 (Time->Minute);
  Packet.DateTime.Hours               = DecimalToBcd8 (Time->Hour);
  Packet.DateTime.Days                = DecimalToBcd8 (Time->Day);
  Packet.DateTime.Weekdays            = 0;
  Packet.DateTime.Century_months      = DecimalToBcd8 (Time->Month);
  Packet.DateTime.Years               = DecimalToBcd8 (Time->Year % 100);
  if (Time->Year >= EPOCH_BASE + 100) {
    if (Time->Year >= EPOCH_BASE + 200) {
      return EFI_DEVICE_ERROR;
    }
    Packet.DateTime.Century_months    |= PCF8563_CENTURY_MASK;
  }

  Packet.Reg = PCF8563_DATA_REG_OFFSET;

  Op.OperationCount                   = 1;
  Op.Operation[0].Flags               = 0;
  Op.Operation[0].LengthInBytes       = sizeof (RTC_SET_DATETIME_PACKET);
  Op.Operation[0].Buffer              = (VOID *)&Packet;

  Status = mI2cMaster->StartRequest (mI2cMaster, SLAVE_ADDRESS,
                         (VOID *)&Op, NULL, NULL);
  if (EFI_ERROR (Status)) {
    return EFI_DEVICE_ERROR;
  }
  return EFI_SUCCESS;
}


/**
  Returns the current wakeup alarm clock setting.

  @param  Enabled               Indicates if the alarm is currently enabled or
                                disabled.
  @param  Pending               Indicates if the alarm signal is pending and
                                requires acknowledgement.
  @param  Time                  The current alarm setting.

  @retval EFI_SUCCESS           The alarm settings were returned.
  @retval EFI_INVALID_PARAMETER Any parameter is NULL.
  @retval EFI_DEVICE_ERROR      The wakeup time could not be retrieved due to a
                                hardware error.
  @retval EFI_UNSUPPORTED       A wakeup timer is not supported on this
                                platform.

**/
EFI_STATUS
EFIAPI
LibGetWakeupTime (
  OUT BOOLEAN     *Enabled,
  OUT BOOLEAN     *Pending,
  OUT EFI_TIME    *Time
  )
{
  //
  // Currently unimplemented. The PCF8563 does not support setting the alarm
  // for an arbitrary date/time, but only for a minute/hour/day/weekday
  // combination. It should also depend on a platform specific setting that
  // indicates whether the PCF8563's interrupt line is connected in a way that
  // allows it to power up the system in the first place.
  //
  return EFI_UNSUPPORTED;
}


/**
  Sets the system wakeup alarm clock time.

  @param  Enabled               Enable or disable the wakeup alarm.
  @param  Time                  If Enable is TRUE, the time to set the wakeup
                                alarm for.

  @retval EFI_SUCCESS           If Enable is TRUE, then the wakeup alarm was
                                enabled. If Enable is FALSE, then the wakeup
                                alarm was disabled.
  @retval EFI_INVALID_PARAMETER A time field is out of range.
  @retval EFI_DEVICE_ERROR      The wakeup time could not be set due to a
                                hardware error.
  @retval EFI_UNSUPPORTED       A wakeup timer is not supported on this
                                platform.

**/
EFI_STATUS
EFIAPI
LibSetWakeupTime (
  IN BOOLEAN      Enabled,
  OUT EFI_TIME    *Time
  )
{
  // see comment above
  return EFI_UNSUPPORTED;
}

STATIC
VOID
I2cMasterRegistrationEvent (
  IN  EFI_EVENT       Event,
  IN  VOID            *Context
  )
{
  EFI_HANDLE                Handle;
  UINTN                     BufferSize;
  EFI_STATUS                Status;
  EFI_I2C_MASTER_PROTOCOL   *I2cMaster;
  UINTN                     BusFrequency;

  //
  // Try to connect the newly registered driver to our handle.
  //
  do {
    BufferSize = sizeof (EFI_HANDLE);
    Status = gBS->LocateHandle (ByRegisterNotify,
                                &gEfiI2cMasterProtocolGuid,
                                mI2cMasterEventRegistration,
                                &BufferSize,
                                &Handle);
    if (EFI_ERROR (Status)) {
      if (Status != EFI_NOT_FOUND) {
        DEBUG ((DEBUG_WARN, "%a: gBS->LocateHandle () returned %r\n",
          __FUNCTION__, Status));
      }
      break;
    }

    if (Handle != mI2cMasterHandle) {
      continue;
    }

    DEBUG ((DEBUG_INFO, "%a: found I2C master!\n", __FUNCTION__));

    gBS->CloseEvent (Event);

    Status = gBS->OpenProtocol (mI2cMasterHandle, &gEfiI2cMasterProtocolGuid,
                    (VOID **)&I2cMaster, gImageHandle, NULL,
                    EFI_OPEN_PROTOCOL_EXCLUSIVE);
    ASSERT_EFI_ERROR (Status);

    Status = I2cMaster->Reset (I2cMaster);
    if (EFI_ERROR (Status)) {
      DEBUG ((DEBUG_ERROR, "%a: I2CMaster->Reset () failed - %r\n",
        __FUNCTION__, Status));
      break;
    }

    BusFrequency = FixedPcdGet16 (PcdI2cBusFrequency);
    Status = I2cMaster->SetBusFrequency (I2cMaster, &BusFrequency);
    if (EFI_ERROR (Status)) {
      DEBUG ((DEBUG_ERROR, "%a: I2CMaster->SetBusFrequency () failed - %r\n",
        __FUNCTION__, Status));
      break;
    }

    mI2cMaster = I2cMaster;
    break;
  } while (TRUE);
}

/**
  Fixup internal data so that EFI can be call in virtual mode.
  Call the passed in Child Notify event and convert any pointers in
  lib to virtual mode.

  @param[in]    Event   The Event that is being processed
  @param[in]    Context Event Context
**/
VOID
EFIAPI
LibRtcVirtualNotifyEvent (
  IN EFI_EVENT        Event,
  IN VOID             *Context
  )
{
  EfiConvertPointer (0x0, (VOID **)&mI2cMaster);
}

/**
  Library entry point

  @param  ImageHandle           Handle that identifies the loaded image.
  @param  SystemTable           System Table for this image.

  @retval EFI_SUCCESS           The operation completed successfully.

**/
EFI_STATUS
EFIAPI
LibRtcInitialize (
  IN EFI_HANDLE                            ImageHandle,
  IN EFI_SYSTEM_TABLE                      *SystemTable
  )
{
  EFI_STATUS          Status;
  UINTN               BufferSize;

  //
  // Find the handle that marks the controller
  // that will provide the I2C master protocol.
  //
  BufferSize = sizeof (EFI_HANDLE);
  Status = gBS->LocateHandle (ByProtocol,
                  &gPcf8563RealTimeClockLibI2cMasterProtocolGuid, NULL,
                  &BufferSize, &mI2cMasterHandle);
  ASSERT_EFI_ERROR (Status);

  //
  // Register a protocol registration notification callback on the I2C master
  // protocol. This will notify us even if the protocol instance we are looking
  // for has already been installed.
  //
  EfiCreateProtocolNotifyEvent (
    &gEfiI2cMasterProtocolGuid,
    TPL_CALLBACK,
    I2cMasterRegistrationEvent,
    NULL,
    &mI2cMasterEventRegistration);

  //
  // Register for the virtual address change event
  //
  Status = gBS->CreateEventEx (EVT_NOTIFY_SIGNAL, TPL_NOTIFY,
                  LibRtcVirtualNotifyEvent, NULL,
                  &gEfiEventVirtualAddressChangeGuid,
                  &mRtcVirtualAddrChangeEvent);
  ASSERT_EFI_ERROR (Status);

  return EFI_SUCCESS;
}