[mirror_edk2.git] / ArmPkg / Drivers / TimerDxe / TimerDxe.c

/** @file\r
  Timer Architecture Protocol driver of the ARM flavor\r
\r
  Copyright (c) 2011-2013 ARM Ltd. All rights reserved.<BR>\r
\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
\r
#include <PiDxe.h>\r
\r
#include <Library/ArmLib.h>\r
#include <Library/BaseLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/BaseMemoryLib.h>\r
#include <Library/UefiBootServicesTableLib.h>\r
#include <Library/UefiLib.h>\r
#include <Library/PcdLib.h>\r
#include <Library/IoLib.h>\r
#include <Library/ArmGenericTimerCounterLib.h>\r
\r
#include <Protocol/Timer.h>\r
#include <Protocol/HardwareInterrupt.h>\r
\r
// The notification function to call on every timer interrupt.\r
EFI_TIMER_NOTIFY      mTimerNotifyFunction     = (EFI_TIMER_NOTIFY)NULL;\r
EFI_EVENT             EfiExitBootServicesEvent = (EFI_EVENT)NULL;\r
\r
// The current period of the timer interrupt\r
UINT64 mTimerPeriod = 0;\r
// The latest Timer Tick calculated for mTimerPeriod\r
UINT64 mTimerTicks = 0;\r
// Number of elapsed period since the last Timer interrupt\r
UINT64 mElapsedPeriod = 1;\r
\r
// Cached copy of the Hardware Interrupt protocol instance\r
EFI_HARDWARE_INTERRUPT_PROTOCOL *gInterrupt = NULL;\r
\r
/**\r
  This function registers the handler NotifyFunction so it is called every time\r
  the timer interrupt fires.  It also passes the amount of time since the last\r
  handler call to the NotifyFunction.  If NotifyFunction is NULL, then the\r
  handler is unregistered.  If the handler is registered, then EFI_SUCCESS is\r
  returned.  If the CPU does not support registering a timer interrupt handler,\r
  then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler\r
  when a handler is already registered, then EFI_ALREADY_STARTED is returned.\r
  If an attempt is made to unregister a handler when a handler is not registered,\r
  then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to\r
  register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR\r
  is returned.\r
\r
  @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.\r
  @param  NotifyFunction   The function to call when a timer interrupt fires. This\r
                           function executes at TPL_HIGH_LEVEL. The DXE Core will\r
                           register a handler for the timer interrupt, so it can know\r
                           how much time has passed. This information is used to\r
                           signal timer based events. NULL will unregister the handler.\r
  @retval EFI_SUCCESS           The timer handler was registered.\r
  @retval EFI_UNSUPPORTED       The platform does not support timer interrupts.\r
  @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already\r
                                registered.\r
  @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not\r
                                previously registered.\r
  @retval EFI_DEVICE_ERROR      The timer handler could not be registered.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
TimerDriverRegisterHandler (\r
  IN EFI_TIMER_ARCH_PROTOCOL  *This,\r
  IN EFI_TIMER_NOTIFY         NotifyFunction\r
  )\r
{\r
  if ((NotifyFunction == NULL) && (mTimerNotifyFunction == NULL)) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  if ((NotifyFunction != NULL) && (mTimerNotifyFunction != NULL)) {\r
    return EFI_ALREADY_STARTED;\r
  }\r
\r
  mTimerNotifyFunction = NotifyFunction;\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
    Disable the timer\r
**/\r
VOID\r
EFIAPI\r
ExitBootServicesEvent (\r
  IN EFI_EVENT  Event,\r
  IN VOID       *Context\r
  )\r
{\r
  ArmGenericTimerDisableTimer ();\r
}\r
\r
/**\r
\r
  This function adjusts the period of timer interrupts to the value specified\r
  by TimerPeriod.  If the timer period is updated, then the selected timer\r
  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If\r
  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.\r
  If an error occurs while attempting to update the timer period, then the\r
  timer hardware will be put back in its state prior to this call, and\r
  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt\r
  is disabled.  This is not the same as disabling the CPU's interrupts.\r
  Instead, it must either turn off the timer hardware, or it must adjust the\r
  interrupt controller so that a CPU interrupt is not generated when the timer\r
  interrupt fires.\r
\r
  @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.\r
  @param  TimerPeriod      The rate to program the timer interrupt in 100 nS units. If\r
                           the timer hardware is not programmable, then EFI_UNSUPPORTED is\r
                           returned. If the timer is programmable, then the timer period\r
                           will be rounded up to the nearest timer period that is supported\r
                           by the timer hardware. If TimerPeriod is set to 0, then the\r
                           timer interrupts will be disabled.\r
\r
\r
  @retval EFI_SUCCESS           The timer period was changed.\r
  @retval EFI_UNSUPPORTED       The platform cannot change the period of the timer interrupt.\r
  @retval EFI_DEVICE_ERROR      The timer period could not be changed due to a device error.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
TimerDriverSetTimerPeriod (\r
  IN EFI_TIMER_ARCH_PROTOCOL  *This,\r
  IN UINT64                   TimerPeriod\r
  )\r
{\r
  UINT64      CounterValue;\r
  UINT64      TimerTicks;\r
  EFI_TPL     OriginalTPL;\r
\r
  // Always disable the timer\r
  ArmGenericTimerDisableTimer ();\r
\r
  if (TimerPeriod != 0) {\r
    // mTimerTicks = TimerPeriod in 1ms unit x Frequency.10^-3\r
    //             = TimerPeriod.10^-4 x Frequency.10^-3\r
    //             = (TimerPeriod x Frequency) x 10^-7\r
    TimerTicks = MultU64x32 (TimerPeriod, ArmGenericTimerGetTimerFreq ());\r
    TimerTicks = DivU64x32 (TimerTicks, 10000000U);\r
\r
    // Raise TPL to update the mTimerTicks and mTimerPeriod to ensure these values\r
    // are coherent in the interrupt handler\r
    OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
\r
    mTimerTicks    = TimerTicks;\r
    mTimerPeriod   = TimerPeriod;\r
    mElapsedPeriod = 1;\r
\r
    gBS->RestoreTPL (OriginalTPL);\r
\r
    // Get value of the current timer\r
    CounterValue = ArmGenericTimerGetSystemCount ();\r
    // Set the interrupt in Current Time + mTimerTick\r
    ArmGenericTimerSetCompareVal (CounterValue + mTimerTicks);\r
\r
    // Enable the timer\r
    ArmGenericTimerEnableTimer ();\r
  } else {\r
    // Save the new timer period\r
    mTimerPeriod   = TimerPeriod;\r
    // Reset the elapsed period\r
    mElapsedPeriod = 1;\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  This function retrieves the period of timer interrupts in 100 ns units,\r
  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod\r
  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is\r
  returned, then the timer is currently disabled.\r
\r
  @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.\r
  @param  TimerPeriod      A pointer to the timer period to retrieve in 100 ns units. If\r
                           0 is returned, then the timer is currently disabled.\r
\r
\r
  @retval EFI_SUCCESS           The timer period was returned in TimerPeriod.\r
  @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
TimerDriverGetTimerPeriod (\r
  IN EFI_TIMER_ARCH_PROTOCOL   *This,\r
  OUT UINT64                   *TimerPeriod\r
  )\r
{\r
  if (TimerPeriod == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  *TimerPeriod = mTimerPeriod;\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  This function generates a soft timer interrupt. If the platform does not support soft\r
  timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.\r
  If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()\r
  service, then a soft timer interrupt will be generated. If the timer interrupt is\r
  enabled when this service is called, then the registered handler will be invoked. The\r
  registered handler should not be able to distinguish a hardware-generated timer\r
  interrupt from a software-generated timer interrupt.\r
\r
  @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.\r
\r
  @retval EFI_SUCCESS           The soft timer interrupt was generated.\r
  @retval EFI_UNSUPPORTED       The platform does not support the generation of soft timer interrupts.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
TimerDriverGenerateSoftInterrupt (\r
  IN EFI_TIMER_ARCH_PROTOCOL  *This\r
  )\r
{\r
  return EFI_UNSUPPORTED;\r
}\r
\r
/**\r
  Interface structure for the Timer Architectural Protocol.\r
\r
  @par Protocol Description:\r
  This protocol provides the services to initialize a periodic timer\r
  interrupt, and to register a handler that is called each time the timer\r
  interrupt fires.  It may also provide a service to adjust the rate of the\r
  periodic timer interrupt.  When a timer interrupt occurs, the handler is\r
  passed the amount of time that has passed since the previous timer\r
  interrupt.\r
\r
  @param RegisterHandler\r
  Registers a handler that will be called each time the\r
  timer interrupt fires.  TimerPeriod defines the minimum\r
  time between timer interrupts, so TimerPeriod will also\r
  be the minimum time between calls to the registered\r
  handler.\r
\r
  @param SetTimerPeriod\r
  Sets the period of the timer interrupt in 100 nS units.\r
  This function is optional, and may return EFI_UNSUPPORTED.\r
  If this function is supported, then the timer period will\r
  be rounded up to the nearest supported timer period.\r
\r
\r
  @param GetTimerPeriod\r
  Retrieves the period of the timer interrupt in 100 nS units.\r
\r
  @param GenerateSoftInterrupt\r
  Generates a soft timer interrupt that simulates the firing of\r
  the timer interrupt. This service can be used to invoke the   registered handler if the timer interrupt has been masked for\r
  a period of time.\r
\r
**/\r
EFI_TIMER_ARCH_PROTOCOL   gTimer = {\r
  TimerDriverRegisterHandler,\r
  TimerDriverSetTimerPeriod,\r
  TimerDriverGetTimerPeriod,\r
  TimerDriverGenerateSoftInterrupt\r
};\r
\r
/**\r
\r
  C Interrupt Handler called in the interrupt context when Source interrupt is active.\r
\r
\r
  @param Source         Source of the interrupt. Hardware routing off a specific platform defines\r
                        what source means.\r
\r
  @param SystemContext  Pointer to system register context. Mostly used by debuggers and will\r
                        update the system context after the return from the interrupt if\r
                        modified. Don't change these values unless you know what you are doing\r
\r
**/\r
VOID\r
EFIAPI\r
TimerInterruptHandler (\r
  IN  HARDWARE_INTERRUPT_SOURCE   Source,\r
  IN  EFI_SYSTEM_CONTEXT          SystemContext\r
  )\r
{\r
  EFI_TPL      OriginalTPL;\r
  UINT64       CurrentValue;\r
  UINT64       CompareValue;\r
\r
  //\r
  // DXE core uses this callback for the EFI timer tick. The DXE core uses locks\r
  // that raise to TPL_HIGH and then restore back to current level. Thus we need\r
  // to make sure TPL level is set to TPL_HIGH while we are handling the timer tick.\r
  //\r
  OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
\r
  // Signal end of interrupt early to help avoid losing subsequent ticks\r
  // from long duration handlers\r
  gInterrupt->EndOfInterrupt (gInterrupt, Source);\r
\r
  // Check if the timer interrupt is active\r
  if ((ArmGenericTimerGetTimerCtrlReg () ) & ARM_ARCH_TIMER_ISTATUS) {\r
\r
    if (mTimerNotifyFunction) {\r
      mTimerNotifyFunction (mTimerPeriod * mElapsedPeriod);\r
    }\r
\r
    //\r
    // Reload the Timer\r
    //\r
\r
    // Get current counter value\r
    CurrentValue = ArmGenericTimerGetSystemCount ();\r
    // Get the counter value to compare with\r
    CompareValue = ArmGenericTimerGetCompareVal ();\r
\r
    // This loop is needed in case we missed interrupts (eg: case when the interrupt handling\r
    // has taken longer than mTickPeriod).\r
    // Note: Physical Counter is counting up\r
    mElapsedPeriod = 0;\r
    do {\r
      CompareValue += mTimerTicks;\r
      mElapsedPeriod++;\r
    } while (CompareValue < CurrentValue);\r
\r
    // Set next compare value\r
    ArmGenericTimerSetCompareVal (CompareValue);\r
    ArmGenericTimerReenableTimer ();\r
    ArmInstructionSynchronizationBarrier ();\r
  }\r
\r
  gBS->RestoreTPL (OriginalTPL);\r
}\r
\r
\r
/**\r
  Initialize the state information for the Timer Architectural Protocol and\r
  the Timer Debug support protocol that allows the debugger to break into a\r
  running program.\r
\r
  @param  ImageHandle   of the loaded driver\r
  @param  SystemTable   Pointer to the System Table\r
\r
  @retval EFI_SUCCESS           Protocol registered\r
  @retval EFI_OUT_OF_RESOURCES  Cannot allocate protocol data structure\r
  @retval EFI_DEVICE_ERROR      Hardware problems\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
TimerInitialize (\r
  IN EFI_HANDLE         ImageHandle,\r
  IN EFI_SYSTEM_TABLE   *SystemTable\r
  )\r
{\r
  EFI_HANDLE  Handle = NULL;\r
  EFI_STATUS  Status;\r
  UINTN       TimerCtrlReg;\r
  UINT32      TimerHypIntrNum;\r
\r
  if (ArmIsArchTimerImplemented () == 0) {\r
    DEBUG ((EFI_D_ERROR, "ARM Architectural Timer is not available in the CPU, hence cann't use this Driver \n"));\r
    ASSERT (0);\r
  }\r
\r
  // Find the interrupt controller protocol.  ASSERT if not found.\r
  Status = gBS->LocateProtocol (&gHardwareInterruptProtocolGuid, NULL, (VOID **)&gInterrupt);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  // Disable the timer\r
  TimerCtrlReg = ArmGenericTimerGetTimerCtrlReg ();\r
  TimerCtrlReg |= ARM_ARCH_TIMER_IMASK;\r
  TimerCtrlReg &= ~ARM_ARCH_TIMER_ENABLE;\r
  ArmGenericTimerSetTimerCtrlReg (TimerCtrlReg);\r
  Status = TimerDriverSetTimerPeriod (&gTimer, 0);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  // Install secure and Non-secure interrupt handlers\r
  // Note: Because it is not possible to determine the security state of the\r
  // CPU dynamically, we just install interrupt handler for both sec and non-sec\r
  // timer PPI\r
  Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerVirtIntrNum), TimerInterruptHandler);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // The hypervisor timer interrupt may be omitted by implementations that\r
  // execute under virtualization.\r
  //\r
  TimerHypIntrNum = PcdGet32 (PcdArmArchTimerHypIntrNum);\r
  if (TimerHypIntrNum != 0) {\r
    Status = gInterrupt->RegisterInterruptSource (gInterrupt, TimerHypIntrNum, TimerInterruptHandler);\r
    ASSERT_EFI_ERROR (Status);\r
  }\r
\r
  Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerSecIntrNum), TimerInterruptHandler);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerIntrNum), TimerInterruptHandler);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  // Set up default timer\r
  Status = TimerDriverSetTimerPeriod (&gTimer, FixedPcdGet32(PcdTimerPeriod)); // TIMER_DEFAULT_PERIOD\r
  ASSERT_EFI_ERROR (Status);\r
\r
  // Install the Timer Architectural Protocol onto a new handle\r
  Status = gBS->InstallMultipleProtocolInterfaces(\r
                  &Handle,\r
                  &gEfiTimerArchProtocolGuid,      &gTimer,\r
                  NULL\r
                  );\r
  ASSERT_EFI_ERROR(Status);\r
\r
  // Everything is ready, unmask and enable timer interrupts\r
  TimerCtrlReg = ARM_ARCH_TIMER_ENABLE;\r
  ArmGenericTimerSetTimerCtrlReg (TimerCtrlReg);\r
\r
  // Register for an ExitBootServicesEvent\r
  Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  return Status;\r
}\r
Commit	Line	Data
	1	/** @file\r
	2	Timer Architecture Protocol driver of the ARM flavor\r
	3	\r
	4	Copyright (c) 2011-2013 ARM Ltd. All rights reserved.<BR>\r
	5	\r
	6	This program and the accompanying materials\r
	7	are licensed and made available under the terms and conditions of the BSD License\r
	8	which accompanies this distribution. The full text of the license may be found at\r
	9	http://opensource.org/licenses/bsd-license.php\r
	10	\r
	11	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	12	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	13	\r
	14	**/\r
	15	\r
	16	\r
	17	#include <PiDxe.h>\r
	18	\r
	19	#include <Library/ArmLib.h>\r
	20	#include <Library/BaseLib.h>\r
	21	#include <Library/DebugLib.h>\r
	22	#include <Library/BaseMemoryLib.h>\r
	23	#include <Library/UefiBootServicesTableLib.h>\r
	24	#include <Library/UefiLib.h>\r
	25	#include <Library/PcdLib.h>\r
	26	#include <Library/IoLib.h>\r
	27	#include <Library/ArmGenericTimerCounterLib.h>\r
	28	\r
	29	#include <Protocol/Timer.h>\r
	30	#include <Protocol/HardwareInterrupt.h>\r
	31	\r
	32	// The notification function to call on every timer interrupt.\r
	33	EFI_TIMER_NOTIFY mTimerNotifyFunction = (EFI_TIMER_NOTIFY)NULL;\r
	34	EFI_EVENT EfiExitBootServicesEvent = (EFI_EVENT)NULL;\r
	35	\r
	36	// The current period of the timer interrupt\r
	37	UINT64 mTimerPeriod = 0;\r
	38	// The latest Timer Tick calculated for mTimerPeriod\r
	39	UINT64 mTimerTicks = 0;\r
	40	// Number of elapsed period since the last Timer interrupt\r
	41	UINT64 mElapsedPeriod = 1;\r
	42	\r
	43	// Cached copy of the Hardware Interrupt protocol instance\r
	44	EFI_HARDWARE_INTERRUPT_PROTOCOL *gInterrupt = NULL;\r
	45	\r
	46	/**\r
	47	This function registers the handler NotifyFunction so it is called every time\r
	48	the timer interrupt fires. It also passes the amount of time since the last\r
	49	handler call to the NotifyFunction. If NotifyFunction is NULL, then the\r
	50	handler is unregistered. If the handler is registered, then EFI_SUCCESS is\r
	51	returned. If the CPU does not support registering a timer interrupt handler,\r
	52	then EFI_UNSUPPORTED is returned. If an attempt is made to register a handler\r
	53	when a handler is already registered, then EFI_ALREADY_STARTED is returned.\r
	54	If an attempt is made to unregister a handler when a handler is not registered,\r
	55	then EFI_INVALID_PARAMETER is returned. If an error occurs attempting to\r
	56	register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR\r
	57	is returned.\r
	58	\r
	59	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
	60	@param NotifyFunction The function to call when a timer interrupt fires. This\r
	61	function executes at TPL_HIGH_LEVEL. The DXE Core will\r
	62	register a handler for the timer interrupt, so it can know\r
	63	how much time has passed. This information is used to\r
	64	signal timer based events. NULL will unregister the handler.\r
	65	@retval EFI_SUCCESS The timer handler was registered.\r
	66	@retval EFI_UNSUPPORTED The platform does not support timer interrupts.\r
	67	@retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already\r
	68	registered.\r
	69	@retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not\r
	70	previously registered.\r
	71	@retval EFI_DEVICE_ERROR The timer handler could not be registered.\r
	72	\r
	73	**/\r
	74	EFI_STATUS\r
	75	EFIAPI\r
	76	TimerDriverRegisterHandler (\r
	77	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
	78	IN EFI_TIMER_NOTIFY NotifyFunction\r
	79	)\r
	80	{\r
	81	if ((NotifyFunction == NULL) && (mTimerNotifyFunction == NULL)) {\r
	82	return EFI_INVALID_PARAMETER;\r
	83	}\r
	84	\r
	85	if ((NotifyFunction != NULL) && (mTimerNotifyFunction != NULL)) {\r
	86	return EFI_ALREADY_STARTED;\r
	87	}\r
	88	\r
	89	mTimerNotifyFunction = NotifyFunction;\r
	90	\r
	91	return EFI_SUCCESS;\r
	92	}\r
	93	\r
	94	/**\r
	95	Disable the timer\r
	96	**/\r
	97	VOID\r
	98	EFIAPI\r
	99	ExitBootServicesEvent (\r
	100	IN EFI_EVENT Event,\r
	101	IN VOID *Context\r
	102	)\r
	103	{\r
	104	ArmGenericTimerDisableTimer ();\r
	105	}\r
	106	\r
	107	/**\r
	108	\r
	109	This function adjusts the period of timer interrupts to the value specified\r
	110	by TimerPeriod. If the timer period is updated, then the selected timer\r
	111	period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If\r
	112	the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.\r
	113	If an error occurs while attempting to update the timer period, then the\r
	114	timer hardware will be put back in its state prior to this call, and\r
	115	EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt\r
	116	is disabled. This is not the same as disabling the CPU's interrupts.\r
	117	Instead, it must either turn off the timer hardware, or it must adjust the\r
	118	interrupt controller so that a CPU interrupt is not generated when the timer\r
	119	interrupt fires.\r
	120	\r
	121	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
	122	@param TimerPeriod The rate to program the timer interrupt in 100 nS units. If\r
	123	the timer hardware is not programmable, then EFI_UNSUPPORTED is\r
	124	returned. If the timer is programmable, then the timer period\r
	125	will be rounded up to the nearest timer period that is supported\r
	126	by the timer hardware. If TimerPeriod is set to 0, then the\r
	127	timer interrupts will be disabled.\r
	128	\r
	129	\r
	130	@retval EFI_SUCCESS The timer period was changed.\r
	131	@retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.\r
	132	@retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.\r
	133	\r
	134	**/\r
	135	EFI_STATUS\r
	136	EFIAPI\r
	137	TimerDriverSetTimerPeriod (\r
	138	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
	139	IN UINT64 TimerPeriod\r
	140	)\r
	141	{\r
	142	UINT64 CounterValue;\r
	143	UINT64 TimerTicks;\r
	144	EFI_TPL OriginalTPL;\r
	145	\r
	146	// Always disable the timer\r
	147	ArmGenericTimerDisableTimer ();\r
	148	\r
	149	if (TimerPeriod != 0) {\r
	150	// mTimerTicks = TimerPeriod in 1ms unit x Frequency.10^-3\r
	151	// = TimerPeriod.10^-4 x Frequency.10^-3\r
	152	// = (TimerPeriod x Frequency) x 10^-7\r
	153	TimerTicks = MultU64x32 (TimerPeriod, ArmGenericTimerGetTimerFreq ());\r
	154	TimerTicks = DivU64x32 (TimerTicks, 10000000U);\r
	155	\r
	156	// Raise TPL to update the mTimerTicks and mTimerPeriod to ensure these values\r
	157	// are coherent in the interrupt handler\r
	158	OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
	159	\r
	160	mTimerTicks = TimerTicks;\r
	161	mTimerPeriod = TimerPeriod;\r
	162	mElapsedPeriod = 1;\r
	163	\r
	164	gBS->RestoreTPL (OriginalTPL);\r
	165	\r
	166	// Get value of the current timer\r
	167	CounterValue = ArmGenericTimerGetSystemCount ();\r
	168	// Set the interrupt in Current Time + mTimerTick\r
	169	ArmGenericTimerSetCompareVal (CounterValue + mTimerTicks);\r
	170	\r
	171	// Enable the timer\r
	172	ArmGenericTimerEnableTimer ();\r
	173	} else {\r
	174	// Save the new timer period\r
	175	mTimerPeriod = TimerPeriod;\r
	176	// Reset the elapsed period\r
	177	mElapsedPeriod = 1;\r
	178	}\r
	179	\r
	180	return EFI_SUCCESS;\r
	181	}\r
	182	\r
	183	/**\r
	184	This function retrieves the period of timer interrupts in 100 ns units,\r
	185	returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod\r
	186	is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is\r
	187	returned, then the timer is currently disabled.\r
	188	\r
	189	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
	190	@param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If\r
	191	0 is returned, then the timer is currently disabled.\r
	192	\r
	193	\r
	194	@retval EFI_SUCCESS The timer period was returned in TimerPeriod.\r
	195	@retval EFI_INVALID_PARAMETER TimerPeriod is NULL.\r
	196	\r
	197	**/\r
	198	EFI_STATUS\r
	199	EFIAPI\r
	200	TimerDriverGetTimerPeriod (\r
	201	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
	202	OUT UINT64 *TimerPeriod\r
	203	)\r
	204	{\r
	205	if (TimerPeriod == NULL) {\r
	206	return EFI_INVALID_PARAMETER;\r
	207	}\r
	208	\r
	209	*TimerPeriod = mTimerPeriod;\r
	210	return EFI_SUCCESS;\r
	211	}\r
	212	\r
	213	/**\r
	214	This function generates a soft timer interrupt. If the platform does not support soft\r
	215	timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.\r
	216	If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()\r
	217	service, then a soft timer interrupt will be generated. If the timer interrupt is\r
	218	enabled when this service is called, then the registered handler will be invoked. The\r
	219	registered handler should not be able to distinguish a hardware-generated timer\r
	220	interrupt from a software-generated timer interrupt.\r
	221	\r
	222	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
	223	\r
	224	@retval EFI_SUCCESS The soft timer interrupt was generated.\r
	225	@retval EFI_UNSUPPORTED The platform does not support the generation of soft timer interrupts.\r
	226	\r
	227	**/\r
	228	EFI_STATUS\r
	229	EFIAPI\r
	230	TimerDriverGenerateSoftInterrupt (\r
	231	IN EFI_TIMER_ARCH_PROTOCOL *This\r
	232	)\r
	233	{\r
	234	return EFI_UNSUPPORTED;\r
	235	}\r
	236	\r
	237	/**\r
	238	Interface structure for the Timer Architectural Protocol.\r
	239	\r
	240	@par Protocol Description:\r
	241	This protocol provides the services to initialize a periodic timer\r
	242	interrupt, and to register a handler that is called each time the timer\r
	243	interrupt fires. It may also provide a service to adjust the rate of the\r
	244	periodic timer interrupt. When a timer interrupt occurs, the handler is\r
	245	passed the amount of time that has passed since the previous timer\r
	246	interrupt.\r
	247	\r
	248	@param RegisterHandler\r
	249	Registers a handler that will be called each time the\r
	250	timer interrupt fires. TimerPeriod defines the minimum\r
	251	time between timer interrupts, so TimerPeriod will also\r
	252	be the minimum time between calls to the registered\r
	253	handler.\r
	254	\r
	255	@param SetTimerPeriod\r
	256	Sets the period of the timer interrupt in 100 nS units.\r
	257	This function is optional, and may return EFI_UNSUPPORTED.\r
	258	If this function is supported, then the timer period will\r
	259	be rounded up to the nearest supported timer period.\r
	260	\r
	261	\r
	262	@param GetTimerPeriod\r
	263	Retrieves the period of the timer interrupt in 100 nS units.\r
	264	\r
	265	@param GenerateSoftInterrupt\r
	266	Generates a soft timer interrupt that simulates the firing of\r
	267	the timer interrupt. This service can be used to invoke the registered handler if the timer interrupt has been masked for\r
	268	a period of time.\r
	269	\r
	270	**/\r
	271	EFI_TIMER_ARCH_PROTOCOL gTimer = {\r
	272	TimerDriverRegisterHandler,\r
	273	TimerDriverSetTimerPeriod,\r
	274	TimerDriverGetTimerPeriod,\r
	275	TimerDriverGenerateSoftInterrupt\r
	276	};\r
	277	\r
	278	/**\r
	279	\r
	280	C Interrupt Handler called in the interrupt context when Source interrupt is active.\r
	281	\r
	282	\r
	283	@param Source Source of the interrupt. Hardware routing off a specific platform defines\r
	284	what source means.\r
	285	\r
	286	@param SystemContext Pointer to system register context. Mostly used by debuggers and will\r
	287	update the system context after the return from the interrupt if\r
	288	modified. Don't change these values unless you know what you are doing\r
	289	\r
	290	**/\r
	291	VOID\r
	292	EFIAPI\r
	293	TimerInterruptHandler (\r
	294	IN HARDWARE_INTERRUPT_SOURCE Source,\r
	295	IN EFI_SYSTEM_CONTEXT SystemContext\r
	296	)\r
	297	{\r
	298	EFI_TPL OriginalTPL;\r
	299	UINT64 CurrentValue;\r
	300	UINT64 CompareValue;\r
	301	\r
	302	//\r
	303	// DXE core uses this callback for the EFI timer tick. The DXE core uses locks\r
	304	// that raise to TPL_HIGH and then restore back to current level. Thus we need\r
	305	// to make sure TPL level is set to TPL_HIGH while we are handling the timer tick.\r
	306	//\r
	307	OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
	308	\r
	309	// Signal end of interrupt early to help avoid losing subsequent ticks\r
	310	// from long duration handlers\r
	311	gInterrupt->EndOfInterrupt (gInterrupt, Source);\r
	312	\r
	313	// Check if the timer interrupt is active\r
	314	if ((ArmGenericTimerGetTimerCtrlReg () ) & ARM_ARCH_TIMER_ISTATUS) {\r
	315	\r
	316	if (mTimerNotifyFunction) {\r
	317	mTimerNotifyFunction (mTimerPeriod * mElapsedPeriod);\r
	318	}\r
	319	\r
	320	//\r
	321	// Reload the Timer\r
	322	//\r
	323	\r
	324	// Get current counter value\r
	325	CurrentValue = ArmGenericTimerGetSystemCount ();\r
	326	// Get the counter value to compare with\r
	327	CompareValue = ArmGenericTimerGetCompareVal ();\r
	328	\r
	329	// This loop is needed in case we missed interrupts (eg: case when the interrupt handling\r
	330	// has taken longer than mTickPeriod).\r
	331	// Note: Physical Counter is counting up\r
	332	mElapsedPeriod = 0;\r
	333	do {\r
	334	CompareValue += mTimerTicks;\r
	335	mElapsedPeriod++;\r
	336	} while (CompareValue < CurrentValue);\r
	337	\r
	338	// Set next compare value\r
	339	ArmGenericTimerSetCompareVal (CompareValue);\r
	340	ArmGenericTimerReenableTimer ();\r
	341	ArmInstructionSynchronizationBarrier ();\r
	342	}\r
	343	\r
	344	gBS->RestoreTPL (OriginalTPL);\r
	345	}\r
	346	\r
	347	\r
	348	/**\r
	349	Initialize the state information for the Timer Architectural Protocol and\r
	350	the Timer Debug support protocol that allows the debugger to break into a\r
	351	running program.\r
	352	\r
	353	@param ImageHandle of the loaded driver\r
	354	@param SystemTable Pointer to the System Table\r
	355	\r
	356	@retval EFI_SUCCESS Protocol registered\r
	357	@retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure\r
	358	@retval EFI_DEVICE_ERROR Hardware problems\r
	359	\r
	360	**/\r
	361	EFI_STATUS\r
	362	EFIAPI\r
	363	TimerInitialize (\r
	364	IN EFI_HANDLE ImageHandle,\r
	365	IN EFI_SYSTEM_TABLE *SystemTable\r
	366	)\r
	367	{\r
	368	EFI_HANDLE Handle = NULL;\r
	369	EFI_STATUS Status;\r
	370	UINTN TimerCtrlReg;\r
	371	UINT32 TimerHypIntrNum;\r
	372	\r
	373	if (ArmIsArchTimerImplemented () == 0) {\r
	374	DEBUG ((EFI_D_ERROR, "ARM Architectural Timer is not available in the CPU, hence cann't use this Driver \n"));\r
	375	ASSERT (0);\r
	376	}\r
	377	\r
	378	// Find the interrupt controller protocol. ASSERT if not found.\r
	379	Status = gBS->LocateProtocol (&gHardwareInterruptProtocolGuid, NULL, (VOID **)&gInterrupt);\r
	380	ASSERT_EFI_ERROR (Status);\r
	381	\r
	382	// Disable the timer\r
	383	TimerCtrlReg = ArmGenericTimerGetTimerCtrlReg ();\r
	384	TimerCtrlReg \|= ARM_ARCH_TIMER_IMASK;\r
	385	TimerCtrlReg &= ~ARM_ARCH_TIMER_ENABLE;\r
	386	ArmGenericTimerSetTimerCtrlReg (TimerCtrlReg);\r
	387	Status = TimerDriverSetTimerPeriod (&gTimer, 0);\r
	388	ASSERT_EFI_ERROR (Status);\r
	389	\r
	390	// Install secure and Non-secure interrupt handlers\r
	391	// Note: Because it is not possible to determine the security state of the\r
	392	// CPU dynamically, we just install interrupt handler for both sec and non-sec\r
	393	// timer PPI\r
	394	Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerVirtIntrNum), TimerInterruptHandler);\r
	395	ASSERT_EFI_ERROR (Status);\r
	396	\r
	397	//\r
	398	// The hypervisor timer interrupt may be omitted by implementations that\r
	399	// execute under virtualization.\r
	400	//\r
	401	TimerHypIntrNum = PcdGet32 (PcdArmArchTimerHypIntrNum);\r
	402	if (TimerHypIntrNum != 0) {\r
	403	Status = gInterrupt->RegisterInterruptSource (gInterrupt, TimerHypIntrNum, TimerInterruptHandler);\r
	404	ASSERT_EFI_ERROR (Status);\r
	405	}\r
	406	\r
	407	Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerSecIntrNum), TimerInterruptHandler);\r
	408	ASSERT_EFI_ERROR (Status);\r
	409	\r
	410	Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerIntrNum), TimerInterruptHandler);\r
	411	ASSERT_EFI_ERROR (Status);\r
	412	\r
	413	// Set up default timer\r
	414	Status = TimerDriverSetTimerPeriod (&gTimer, FixedPcdGet32(PcdTimerPeriod)); // TIMER_DEFAULT_PERIOD\r
	415	ASSERT_EFI_ERROR (Status);\r
	416	\r
	417	// Install the Timer Architectural Protocol onto a new handle\r
	418	Status = gBS->InstallMultipleProtocolInterfaces(\r
	419	&Handle,\r
	420	&gEfiTimerArchProtocolGuid, &gTimer,\r
	421	NULL\r
	422	);\r
	423	ASSERT_EFI_ERROR(Status);\r
	424	\r
	425	// Everything is ready, unmask and enable timer interrupts\r
	426	TimerCtrlReg = ARM_ARCH_TIMER_ENABLE;\r
	427	ArmGenericTimerSetTimerCtrlReg (TimerCtrlReg);\r
	428	\r
	429	// Register for an ExitBootServicesEvent\r
	430	Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent);\r
	431	ASSERT_EFI_ERROR (Status);\r
	432	\r
	433	return Status;\r
	434	}\r