[mirror_edk2.git] / ArmPlatformPkg / Drivers / SP805WatchdogDxe / SP805Watchdog.c

/** @file
*
*  Copyright (c) 2011, ARM Limited. All rights reserved.
*
*  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/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/IoLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
#include <Library/UefiLib.h>

#include <Protocol/WatchdogTimer.h>
#include <Drivers/SP805Watchdog.h>

EFI_EVENT                           EfiExitBootServicesEvent = (EFI_EVENT)NULL;

BOOLEAN                             mSP805Initialized = FALSE;

EFI_STATUS
SP805Identify (
  VOID
  )
{
  // Check if this is a PrimeCell Peripheral
  if (    (MmioRead8 (SP805_WDOG_PCELL_ID0) != 0x0D)
      ||  (MmioRead8 (SP805_WDOG_PCELL_ID1) != 0xF0)
      ||  (MmioRead8 (SP805_WDOG_PCELL_ID2) != 0x05)
      ||  (MmioRead8 (SP805_WDOG_PCELL_ID3) != 0xB1)) {
    return EFI_NOT_FOUND;
  }

  // Check if this PrimeCell Peripheral is the SP805 Watchdog Timer
  if (    (MmioRead8 (SP805_WDOG_PERIPH_ID0) != 0x05)
      ||  (MmioRead8 (SP805_WDOG_PERIPH_ID1) != 0x18)
      || ((MmioRead8 (SP805_WDOG_PERIPH_ID2) & 0x0000000F) != 0x04)
      ||  (MmioRead8 (SP805_WDOG_PERIPH_ID3) != 0x00)) {
    return EFI_NOT_FOUND;
  }

  return EFI_SUCCESS;
}

/**
  Make sure the SP805 registers are unlocked for writing.

  Note: The SP805 Watchdog Timer supports locking of its registers,
  i.e. it inhibits all writes to avoid rogue software accidentally
  corrupting their contents.
**/
inline
VOID
SP805Unlock (
  VOID
  )
{
  if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_LOCKED ) {
    MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_SPECIAL_UNLOCK_CODE);
  }
}

/**
  Make sure the SP805 registers are locked and can not be overwritten.

  Note: The SP805 Watchdog Timer supports locking of its registers,
  i.e. it inhibits all writes to avoid rogue software accidentally
  corrupting their contents.
**/
inline
VOID
SP805Lock (
  VOID
  )
{
  if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_UNLOCKED ) {
    // To lock it, just write in any number (except the special unlock code).
    MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_LOCK_IS_LOCKED);
  }
}

/**
  Stop the SP805 watchdog timer from counting down by disabling interrupts.
**/
inline
VOID
SP805Stop (
  VOID
  )
{
  // Disable interrupts
  if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) != 0 ) {
    MmioAnd32(SP805_WDOG_CONTROL_REG, ~SP805_WDOG_CTRL_INTEN);
  }
}

/**
  Starts the SP805 counting down by enabling interrupts.
  The count down will start from the value stored in the Load register,
  not from the value where it was previously stopped.
**/
inline
VOID
SP805Start (
  VOID
  )
{
  // Enable interrupts
  if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) {
    MmioOr32(SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_INTEN);
  }
}

/**
    On exiting boot services we must make sure the SP805 Watchdog Timer
    is stopped.
**/
VOID
EFIAPI
ExitBootServicesEvent (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  SP805Unlock();
  SP805Stop();
  SP805Lock();
}

/**
  This function registers the handler NotifyFunction so it is called every time
  the watchdog timer expires.  It also passes the amount of time since the last
  handler call to the NotifyFunction.
  If NotifyFunction is not NULL and a handler is not already registered,
  then the new handler is registered and EFI_SUCCESS is returned.
  If NotifyFunction is NULL, and a handler is already registered,
  then that handler is unregistered.
  If an attempt is made to register a handler when a handler is already registered,
  then EFI_ALREADY_STARTED is returned.
  If an attempt is made to unregister a handler when a handler is not registered,
  then EFI_INVALID_PARAMETER is returned.

  @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
  @param  NotifyFunction   The function to call when a timer interrupt fires. This
                           function executes at TPL_HIGH_LEVEL. The DXE Core will
                           register a handler for the timer interrupt, so it can know
                           how much time has passed. This information is used to
                           signal timer based events. NULL will unregister the handler.

  @retval EFI_SUCCESS           The watchdog timer handler was registered.
  @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already
                                registered.
  @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
                                previously registered.

**/
EFI_STATUS
EFIAPI
SP805RegisterHandler (
  IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL   *This,
  IN EFI_WATCHDOG_TIMER_NOTIFY                NotifyFunction
  )
{
  // ERROR: This function is not supported.
  // The hardware watchdog will reset the board
  return EFI_INVALID_PARAMETER;
}

/**

  This function adjusts the period of timer interrupts to the value specified
  by TimerPeriod.  If the timer period is updated, then the selected timer
  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
  If an error occurs while attempting to update the timer period, then the
  timer hardware will be put back in its state prior to this call, and
  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
  is disabled.  This is not the same as disabling the CPU's interrupts.
  Instead, it must either turn off the timer hardware, or it must adjust the
  interrupt controller so that a CPU interrupt is not generated when the timer
  interrupt fires.

  @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
  @param  TimerPeriod      The rate to program the timer interrupt in 100 nS units. If
                           the timer hardware is not programmable, then EFI_UNSUPPORTED is
                           returned. If the timer is programmable, then the timer period
                           will be rounded up to the nearest timer period that is supported
                           by the timer hardware. If TimerPeriod is set to 0, then the
                           timer interrupts will be disabled.


  @retval EFI_SUCCESS           The timer period was changed.
  @retval EFI_UNSUPPORTED       The platform cannot change the period of the timer interrupt.
  @retval EFI_DEVICE_ERROR      The timer period could not be changed due to a device error.

**/
EFI_STATUS
EFIAPI
SP805SetTimerPeriod (
  IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL   *This,
  IN UINT64                                   TimerPeriod   // In 100ns units
  )
{
  EFI_STATUS  Status = EFI_SUCCESS;
  UINT64      Ticks64bit;

  // Initialize the hardware if not already done
  if( !mSP805Initialized ) {
    Status = SP805Initialize();
    if (EFI_ERROR(Status)) {
      goto EXIT;
    }
  }

  SP805Unlock();

  if( TimerPeriod == 0 ) {
    // This is a watchdog stop request
    SP805Stop();
    goto EXIT;
  } else {
    // Calculate the Watchdog ticks required for a delay of (TimerTicks * 100) nanoseconds
    // The SP805 will count down to ZERO once, generate an interrupt and
    // then it will again reload the initial value and start again.
    // On the second time when it reaches ZERO, it will actually reset the board.
    // Therefore, we need to load half the required delay.
    //
    // WatchdogTicks = ((TimerPeriod * 100 * SP805_CLOCK_FREQUENCY) / 1GHz) / 2 ;
    //
    // i.e.:
    //
    // WatchdogTicks = (TimerPeriod * SP805_CLOCK_FREQUENCY) / 20 MHz ;

    Ticks64bit = DivU64x32(MultU64x32(TimerPeriod, (UINTN)PcdGet32(PcdSP805WatchdogClockFrequencyInHz)), 20000000);

    // The registers in the SP805 are only 32 bits
    if(Ticks64bit > (UINT64)0xFFFFFFFF) {
      // We could load the watchdog with the maximum supported value but
      // if a smaller value was requested, this could have the watchdog
      // triggering before it was intended.
      // Better generate an error to let the caller know.
      Status = EFI_DEVICE_ERROR;
      goto EXIT;
    }

    // Update the watchdog with a 32-bit value.
    MmioWrite32(SP805_WDOG_LOAD_REG, (UINT32)Ticks64bit);

    // Start the watchdog
    SP805Start();
  }

  EXIT:
  // Ensure the watchdog is locked before exiting.
  SP805Lock();
  return Status;
}

/**
  This function retrieves the period of timer interrupts in 100 ns units,
  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
  returned, then the timer is currently disabled.

  @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
  @param  TimerPeriod      A pointer to the timer period to retrieve in 100 ns units. If
                           0 is returned, then the timer is currently disabled.


  @retval EFI_SUCCESS           The timer period was returned in TimerPeriod.
  @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.

**/
EFI_STATUS
EFIAPI
SP805GetTimerPeriod (
  IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL   *This,
  OUT UINT64                                  *TimerPeriod
  )
{
  EFI_STATUS  Status = EFI_SUCCESS;
  UINT64      ReturnValue;

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

  // Initialize the hardware if not already done
  if( !mSP805Initialized ) {
    Status = SP805Initialize();
    if (EFI_ERROR(Status)) {
      goto EXIT;
    }
  }

  // Check if the watchdog is stopped
  if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) {
    // It is stopped, so return zero.
    ReturnValue = 0;
  } else {
    // Convert the Watchdog ticks into TimerPeriod
    // Ensure 64bit arithmetic throughout because the Watchdog ticks may already
    // be at the maximum 32 bit value and we still need to multiply that by 600.
    ReturnValue = MultU64x32( MmioRead32(SP805_WDOG_LOAD_REG), 600 );
  }

  *TimerPeriod = ReturnValue;

  return Status;
}

/**
  Interface structure for the Watchdog Architectural Protocol.

  @par Protocol Description:
  This protocol provides a service to set the amount of time to wait
  before firing the watchdog timer, and it also provides a service to
  register a handler that is invoked when the watchdog timer fires.

  @par When the watchdog timer fires, control will be passed to a handler
  if one has been registered.  If no handler has been registered,
  or the registered handler returns, then the system will be
  reset by calling the Runtime Service ResetSystem().

  @param RegisterHandler
  Registers a handler that will be called each time the
  watchdogtimer interrupt fires.  TimerPeriod defines the minimum
  time between timer interrupts, so TimerPeriod will also
  be the minimum time between calls to the registered
  handler.
  NOTE: If the watchdog resets the system in hardware, then
        this function will not have any chance of executing.

  @param SetTimerPeriod
  Sets the period of the timer interrupt in 100 nS units.
  This function is optional, and may return EFI_UNSUPPORTED.
  If this function is supported, then the timer period will
  be rounded up to the nearest supported timer period.

  @param GetTimerPeriod
  Retrieves the period of the timer interrupt in 100 nS units.

**/
EFI_WATCHDOG_TIMER_ARCH_PROTOCOL    gWatchdogTimer = {
  (EFI_WATCHDOG_TIMER_REGISTER_HANDLER) SP805RegisterHandler,
  (EFI_WATCHDOG_TIMER_SET_TIMER_PERIOD) SP805SetTimerPeriod,
  (EFI_WATCHDOG_TIMER_GET_TIMER_PERIOD) SP805GetTimerPeriod
};

/**
  Initialize the state information for the Watchdog Timer Architectural Protocol.

  @param  ImageHandle   of the loaded driver
  @param  SystemTable   Pointer to the System Table

  @retval EFI_SUCCESS           Protocol registered
  @retval EFI_OUT_OF_RESOURCES  Cannot allocate protocol data structure
  @retval EFI_DEVICE_ERROR      Hardware problems

**/
EFI_STATUS
SP805Initialize (
  VOID
  )
{
  EFI_STATUS  Status;

  // Check if the SP805 hardware watchdog module exists on board
  Status = SP805Identify();
  if (EFI_ERROR(Status)) {
    Status = EFI_DEVICE_ERROR;
    goto EXIT;
  }

  // Unlock access to the SP805 registers
  SP805Unlock ();

  // Stop the watchdog from triggering unexpectedly
  SP805Stop ();

  // Set the watchdog to reset the board when triggered
  if ((MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_RESEN) == 0) {
    MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_RESEN);
  }

  // Prohibit any rogue access to SP805 registers
  SP805Lock();

  mSP805Initialized = TRUE;

  EXIT:
  return Status;
}

EFI_STATUS
EFIAPI
SP805InstallProtocol (
  IN EFI_HANDLE         ImageHandle,
  IN EFI_SYSTEM_TABLE   *SystemTable
  )
{
  EFI_STATUS  Status;
  EFI_HANDLE  Handle;

  //
  // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
  // This will avoid conflicts with the universal watchdog
  //
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);

  // Register for an ExitBootServicesEvent
  Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent);
  if (EFI_ERROR(Status)) {
    Status = EFI_OUT_OF_RESOURCES;
    goto EXIT;
  }

  // Install the Timer Architectural Protocol onto a new handle
  Handle = NULL;
  Status = gBS->InstallMultipleProtocolInterfaces(
                  &Handle,
                  &gEfiWatchdogTimerArchProtocolGuid, &gWatchdogTimer,
                  NULL
                  );
  if (EFI_ERROR(Status)) {
    Status = EFI_OUT_OF_RESOURCES;
    goto EXIT;
  }

  EXIT:
  if(EFI_ERROR(Status)) {
    // The watchdog failed to initialize
    ASSERT(FALSE);
  }
  return Status;
}
Commit	Line	Data
33e7c2ab	1	/** @file
	2	*
	3	* Copyright (c) 2011, ARM Limited. All rights reserved.
	4	*
	5	* This program and the accompanying materials
	6	* are licensed and made available under the terms and conditions of the BSD License
	7	* which accompanies this distribution. The full text of the license may be found at
	8	* http://opensource.org/licenses/bsd-license.php
	9	*
	10	* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
	11	* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
	12	*
	13	**/
	14
	15
	16	#include <PiDxe.h>
	17
	18	#include <Library/BaseLib.h>
33e7c2ab	19	#include <Library/BaseMemoryLib.h>
5cc45b70	20	#include <Library/DebugLib.h>
	21	#include <Library/IoLib.h>
	22	#include <Library/PcdLib.h>
33e7c2ab	23	#include <Library/UefiBootServicesTableLib.h>
	24	#include <Library/UefiRuntimeServicesTableLib.h>
	25	#include <Library/UefiLib.h>
33e7c2ab	26
33e7c2ab	27	#include <Protocol/WatchdogTimer.h>
33e7c2ab	28	#include <Drivers/SP805Watchdog.h>
33e7c2ab	29
33e7c2ab	30	EFI_EVENT EfiExitBootServicesEvent = (EFI_EVENT)NULL;
	31
	32	BOOLEAN mSP805Initialized = FALSE;
	33
	34	EFI_STATUS
	35	SP805Identify (
	36	VOID
	37	)
	38	{
	39	// Check if this is a PrimeCell Peripheral
5cc45b70	40	if ( (MmioRead8 (SP805_WDOG_PCELL_ID0) != 0x0D)
	41	\|\| (MmioRead8 (SP805_WDOG_PCELL_ID1) != 0xF0)
	42	\|\| (MmioRead8 (SP805_WDOG_PCELL_ID2) != 0x05)
	43	\|\| (MmioRead8 (SP805_WDOG_PCELL_ID3) != 0xB1)) {
33e7c2ab	44	return EFI_NOT_FOUND;
	45	}
	46
	47	// Check if this PrimeCell Peripheral is the SP805 Watchdog Timer
5cc45b70	48	if ( (MmioRead8 (SP805_WDOG_PERIPH_ID0) != 0x05)
	49	\|\| (MmioRead8 (SP805_WDOG_PERIPH_ID1) != 0x18)
	50	\|\| ((MmioRead8 (SP805_WDOG_PERIPH_ID2) & 0x0000000F) != 0x04)
	51	\|\| (MmioRead8 (SP805_WDOG_PERIPH_ID3) != 0x00)) {
33e7c2ab	52	return EFI_NOT_FOUND;
	53	}
	54
	55	return EFI_SUCCESS;
	56	}
	57
	58	/**
	59	Make sure the SP805 registers are unlocked for writing.
	60
	61	Note: The SP805 Watchdog Timer supports locking of its registers,
	62	i.e. it inhibits all writes to avoid rogue software accidentally
	63	corrupting their contents.
	64	**/
	65	inline
	66	VOID
	67	SP805Unlock (
	68	VOID
	69	)
	70	{
	71	if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_LOCKED ) {
	72	MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_SPECIAL_UNLOCK_CODE);
	73	}
	74	}
	75
	76	/**
	77	Make sure the SP805 registers are locked and can not be overwritten.
	78
	79	Note: The SP805 Watchdog Timer supports locking of its registers,
	80	i.e. it inhibits all writes to avoid rogue software accidentally
	81	corrupting their contents.
	82	**/
	83	inline
	84	VOID
	85	SP805Lock (
	86	VOID
	87	)
	88	{
	89	if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_UNLOCKED ) {
	90	// To lock it, just write in any number (except the special unlock code).
	91	MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_LOCK_IS_LOCKED);
	92	}
	93	}
	94
	95	/**
	96	Stop the SP805 watchdog timer from counting down by disabling interrupts.
	97	**/
	98	inline
	99	VOID
	100	SP805Stop (
	101	VOID
	102	)
	103	{
	104	// Disable interrupts
	105	if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) != 0 ) {
	106	MmioAnd32(SP805_WDOG_CONTROL_REG, ~SP805_WDOG_CTRL_INTEN);
	107	}
	108	}
	109
	110	/**
	111	Starts the SP805 counting down by enabling interrupts.
	112	The count down will start from the value stored in the Load register,
	113	not from the value where it was previously stopped.
	114	**/
	115	inline
116	VOID
117	SP805Start (
118	VOID
119	)
120	{
121	// Enable interrupts
122	if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) {
123	MmioOr32(SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_INTEN);
124	}
125	}
126
127	/**
128	On exiting boot services we must make sure the SP805 Watchdog Timer
129	is stopped.
130	**/
131	VOID
132	EFIAPI
133	ExitBootServicesEvent (
134	IN EFI_EVENT Event,
135	IN VOID *Context
136	)
137	{
138	SP805Unlock();
139	SP805Stop();
140	SP805Lock();
141	}
142
143	/**
144	This function registers the handler NotifyFunction so it is called every time
145	the watchdog timer expires. It also passes the amount of time since the last
146	handler call to the NotifyFunction.
147	If NotifyFunction is not NULL and a handler is not already registered,
148	then the new handler is registered and EFI_SUCCESS is returned.
149	If NotifyFunction is NULL, and a handler is already registered,
150	then that handler is unregistered.
151	If an attempt is made to register a handler when a handler is already registered,
152	then EFI_ALREADY_STARTED is returned.
153	If an attempt is made to unregister a handler when a handler is not registered,
154	then EFI_INVALID_PARAMETER is returned.
155
156	@param This The EFI_TIMER_ARCH_PROTOCOL instance.
157	@param NotifyFunction The function to call when a timer interrupt fires. This
158	function executes at TPL_HIGH_LEVEL. The DXE Core will
159	register a handler for the timer interrupt, so it can know
160	how much time has passed. This information is used to
161	signal timer based events. NULL will unregister the handler.
162
163	@retval EFI_SUCCESS The watchdog timer handler was registered.
164	@retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already
165	registered.
166	@retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
167	previously registered.
168
169	**/
170	EFI_STATUS
171	EFIAPI
172	SP805RegisterHandler (
173	IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
174	IN EFI_WATCHDOG_TIMER_NOTIFY NotifyFunction
175	)
176	{
177	// ERROR: This function is not supported.
178	// The hardware watchdog will reset the board
179	return EFI_INVALID_PARAMETER;
180	}
181
182	/**
183
184	This function adjusts the period of timer interrupts to the value specified
185	by TimerPeriod. If the timer period is updated, then the selected timer
186	period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If
187	the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
188	If an error occurs while attempting to update the timer period, then the
189	timer hardware will be put back in its state prior to this call, and
190	EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt
191	is disabled. This is not the same as disabling the CPU's interrupts.
192	Instead, it must either turn off the timer hardware, or it must adjust the
193	interrupt controller so that a CPU interrupt is not generated when the timer
194	interrupt fires.
195
196	@param This The EFI_TIMER_ARCH_PROTOCOL instance.
197	@param TimerPeriod The rate to program the timer interrupt in 100 nS units. If
198	the timer hardware is not programmable, then EFI_UNSUPPORTED is
199	returned. If the timer is programmable, then the timer period
200	will be rounded up to the nearest timer period that is supported
201	by the timer hardware. If TimerPeriod is set to 0, then the
202	timer interrupts will be disabled.
203
204
205	@retval EFI_SUCCESS The timer period was changed.
206	@retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.
207	@retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.
208
209	**/
210	EFI_STATUS
211	EFIAPI
212	SP805SetTimerPeriod (
213	IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
214	IN UINT64 TimerPeriod // In 100ns units
215	)
216	{
217	EFI_STATUS Status = EFI_SUCCESS;
218	UINT64 Ticks64bit;
219
220	// Initialize the hardware if not already done
221	if( !mSP805Initialized ) {
222	Status = SP805Initialize();
223	if (EFI_ERROR(Status)) {
224	goto EXIT;
225	}
226	}
227
228	SP805Unlock();
229
230	if( TimerPeriod == 0 ) {
231	// This is a watchdog stop request
232	SP805Stop();
233	goto EXIT;
234	} else {
235	// Calculate the Watchdog ticks required for a delay of (TimerTicks * 100) nanoseconds
236	// The SP805 will count down to ZERO once, generate an interrupt and
237	// then it will again reload the initial value and start again.
238	// On the second time when it reaches ZERO, it will actually reset the board.
239	// Therefore, we need to load half the required delay.
240	//
241	// WatchdogTicks = ((TimerPeriod * 100 * SP805_CLOCK_FREQUENCY) / 1GHz) / 2 ;
242	//
243	// i.e.:
244	//
245	// WatchdogTicks = (TimerPeriod * SP805_CLOCK_FREQUENCY) / 20 MHz ;
246
3723a71a	247	Ticks64bit = DivU64x32(MultU64x32(TimerPeriod, (UINTN)PcdGet32(PcdSP805WatchdogClockFrequencyInHz)), 20000000);
33e7c2ab	248
33e7c2ab	249	// The registers in the SP805 are only 32 bits
3723a71a	250	if(Ticks64bit > (UINT64)0xFFFFFFFF) {
33e7c2ab	251	// We could load the watchdog with the maximum supported value but
	252	// if a smaller value was requested, this could have the watchdog
	253	// triggering before it was intended.
	254	// Better generate an error to let the caller know.
	255	Status = EFI_DEVICE_ERROR;
	256	goto EXIT;
	257	}
	258
	259	// Update the watchdog with a 32-bit value.
	260	MmioWrite32(SP805_WDOG_LOAD_REG, (UINT32)Ticks64bit);
	261
	262	// Start the watchdog
	263	SP805Start();
	264	}
	265
	266	EXIT:
	267	// Ensure the watchdog is locked before exiting.
	268	SP805Lock();
	269	return Status;
	270	}
	271
	272	/**
	273	This function retrieves the period of timer interrupts in 100 ns units,
	274	returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod
	275	is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is
	276	returned, then the timer is currently disabled.
	277
	278	@param This The EFI_TIMER_ARCH_PROTOCOL instance.
	279	@param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If
	280	0 is returned, then the timer is currently disabled.
	281
	282
	283	@retval EFI_SUCCESS The timer period was returned in TimerPeriod.
	284	@retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
	285
	286	**/
	287	EFI_STATUS
	288	EFIAPI
	289	SP805GetTimerPeriod (
	290	IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
	291	OUT UINT64 *TimerPeriod
	292	)
	293	{
	294	EFI_STATUS Status = EFI_SUCCESS;
	295	UINT64 ReturnValue;
	296
	297	if (TimerPeriod == NULL) {
	298	return EFI_INVALID_PARAMETER;
	299	}
	300
	301	// Initialize the hardware if not already done
	302	if( !mSP805Initialized ) {
	303	Status = SP805Initialize();
	304	if (EFI_ERROR(Status)) {
	305	goto EXIT;
	306	}
	307	}
	308
	309	// Check if the watchdog is stopped
	310	if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) {
	311	// It is stopped, so return zero.
	312	ReturnValue = 0;
	313	} else {
	314	// Convert the Watchdog ticks into TimerPeriod
315	// Ensure 64bit arithmetic throughout because the Watchdog ticks may already
316	// be at the maximum 32 bit value and we still need to multiply that by 600.
317	ReturnValue = MultU64x32( MmioRead32(SP805_WDOG_LOAD_REG), 600 );
318	}
319
320	*TimerPeriod = ReturnValue;
321
33e7c2ab	322	return Status;
	323	}
	324
a12da33b	325	/**
	326	Interface structure for the Watchdog Architectural Protocol.
	327
	328	@par Protocol Description:
	329	This protocol provides a service to set the amount of time to wait
	330	before firing the watchdog timer, and it also provides a service to
	331	register a handler that is invoked when the watchdog timer fires.
	332
	333	@par When the watchdog timer fires, control will be passed to a handler
	334	if one has been registered. If no handler has been registered,
	335	or the registered handler returns, then the system will be
	336	reset by calling the Runtime Service ResetSystem().
	337
	338	@param RegisterHandler
	339	Registers a handler that will be called each time the
	340	watchdogtimer interrupt fires. TimerPeriod defines the minimum
	341	time between timer interrupts, so TimerPeriod will also
	342	be the minimum time between calls to the registered
	343	handler.
	344	NOTE: If the watchdog resets the system in hardware, then
	345	this function will not have any chance of executing.
	346
	347	@param SetTimerPeriod
	348	Sets the period of the timer interrupt in 100 nS units.
	349	This function is optional, and may return EFI_UNSUPPORTED.
	350	If this function is supported, then the timer period will
	351	be rounded up to the nearest supported timer period.
	352
	353	@param GetTimerPeriod
	354	Retrieves the period of the timer interrupt in 100 nS units.
	355
	356	**/
	357	EFI_WATCHDOG_TIMER_ARCH_PROTOCOL gWatchdogTimer = {
	358	(EFI_WATCHDOG_TIMER_REGISTER_HANDLER) SP805RegisterHandler,
	359	(EFI_WATCHDOG_TIMER_SET_TIMER_PERIOD) SP805SetTimerPeriod,
	360	(EFI_WATCHDOG_TIMER_GET_TIMER_PERIOD) SP805GetTimerPeriod
	361	};
	362
33e7c2ab	363	/**
	364	Initialize the state information for the Watchdog Timer Architectural Protocol.
	365
	366	@param ImageHandle of the loaded driver
	367	@param SystemTable Pointer to the System Table
	368
	369	@retval EFI_SUCCESS Protocol registered
	370	@retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure
	371	@retval EFI_DEVICE_ERROR Hardware problems
	372
	373	**/
	374	EFI_STATUS
	375	SP805Initialize (
	376	VOID
	377	)
	378	{
	379	EFI_STATUS Status;
	380
	381	// Check if the SP805 hardware watchdog module exists on board
	382	Status = SP805Identify();
a12da33b	383	if (EFI_ERROR(Status)) {
33e7c2ab	384	Status = EFI_DEVICE_ERROR;
	385	goto EXIT;
	386	}
	387
	388	// Unlock access to the SP805 registers
a12da33b	389	SP805Unlock ();
33e7c2ab	390
33e7c2ab	391	// Stop the watchdog from triggering unexpectedly
a12da33b	392	SP805Stop ();
33e7c2ab	393
33e7c2ab	394	// Set the watchdog to reset the board when triggered
a12da33b	395	if ((MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_RESEN) == 0) {
a12da33b	396	MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_RESEN);
33e7c2ab	397	}
	398
	399	// Prohibit any rogue access to SP805 registers
	400	SP805Lock();
	401
	402	mSP805Initialized = TRUE;
	403
	404	EXIT:
	405	return Status;
	406	}
	407
	408	EFI_STATUS
	409	EFIAPI
	410	SP805InstallProtocol (
	411	IN EFI_HANDLE ImageHandle,
	412	IN EFI_SYSTEM_TABLE *SystemTable
	413	)
	414	{
	415	EFI_STATUS Status;
	416	EFI_HANDLE Handle;
	417
	418	//
	419	// Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
	420	// This will avoid conflicts with the universal watchdog
	421	//
	422	ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);
	423
	424	// Register for an ExitBootServicesEvent
	425	Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent);
	426	if (EFI_ERROR(Status)) {
	427	Status = EFI_OUT_OF_RESOURCES;
	428	goto EXIT;
	429	}
	430
	431	// Install the Timer Architectural Protocol onto a new handle
	432	Handle = NULL;
	433	Status = gBS->InstallMultipleProtocolInterfaces(
	434	&Handle,
	435	&gEfiWatchdogTimerArchProtocolGuid, &gWatchdogTimer,
	436	NULL
	437	);
	438	if (EFI_ERROR(Status)) {
	439	Status = EFI_OUT_OF_RESOURCES;
	440	goto EXIT;
	441	}
	442
	443	EXIT:
	444	if(EFI_ERROR(Status)) {
	445	// The watchdog failed to initialize
	446	ASSERT(FALSE);
	447	}
	448	return Status;
	449	}