[mirror_edk2.git] / OvmfPkg / XenTimerDxe / XenTimerDxe.c

/** @file\r
  Timer Architectural Protocol as defined in the DXE CIS\r
\r
Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>\r
Copyright (c) 2019, Citrix Systems, Inc.\r
\r
SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include "XenTimerDxe.h"\r
\r
//\r
// The handle onto which the Timer Architectural Protocol will be installed\r
//\r
EFI_HANDLE  mTimerHandle = NULL;\r
\r
//\r
// The Timer Architectural Protocol that this driver produces\r
//\r
EFI_TIMER_ARCH_PROTOCOL  mTimer = {\r
  TimerDriverRegisterHandler,\r
  TimerDriverSetTimerPeriod,\r
  TimerDriverGetTimerPeriod,\r
  TimerDriverGenerateSoftInterrupt\r
};\r
\r
//\r
// Pointer to the CPU Architectural Protocol instance\r
//\r
EFI_CPU_ARCH_PROTOCOL  *mCpu;\r
\r
//\r
// The notification function to call on every timer interrupt.\r
// A bug in the compiler prevents us from initializing this here.\r
//\r
EFI_TIMER_NOTIFY  mTimerNotifyFunction;\r
\r
//\r
// The current period of the timer interrupt\r
//\r
volatile UINT64  mTimerPeriod = 0;\r
\r
//\r
// Worker Functions\r
//\r
\r
/**\r
  Interrupt Handler.\r
\r
  @param InterruptType    The type of interrupt that occurred\r
  @param SystemContext    A pointer to the system context when the interrupt occurred\r
**/\r
VOID\r
EFIAPI\r
TimerInterruptHandler (\r
  IN EFI_EXCEPTION_TYPE  InterruptType,\r
  IN EFI_SYSTEM_CONTEXT  SystemContext\r
  )\r
{\r
  EFI_TPL  OriginalTPL;\r
\r
  OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
\r
  if (mTimerNotifyFunction != NULL) {\r
    //\r
    // @bug : This does not handle missed timer interrupts\r
    //\r
    mTimerNotifyFunction (mTimerPeriod);\r
  }\r
\r
  gBS->RestoreTPL (OriginalTPL);\r
\r
  DisableInterrupts ();\r
  SendApicEoi ();\r
}\r
\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
\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
\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
  //\r
  // Check for invalid parameters\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
\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
\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
  @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  TimerCount;\r
  UINT32  TimerFrequency;\r
  UINT32  DivideValue = 1;\r
\r
  if (TimerPeriod == 0) {\r
    //\r
    // Disable timer interrupt for a TimerPeriod of 0\r
    //\r
    DisableApicTimerInterrupt ();\r
  } else {\r
    TimerFrequency = PcdGet32 (PcdFSBClock) / DivideValue;\r
\r
    //\r
    // Convert TimerPeriod into local APIC counts\r
    //\r
    // TimerPeriod is in 100ns\r
    // TimerPeriod/10000000 will be in seconds.\r
    TimerCount = DivU64x32 (\r
                   MultU64x32 (TimerPeriod, TimerFrequency),\r
                   10000000\r
                   );\r
\r
    // Check for overflow\r
    if (TimerCount > MAX_UINT32) {\r
      TimerCount = MAX_UINT32;\r
      /* TimerPeriod = (MAX_UINT32 / TimerFrequency) * 10000000; */\r
      TimerPeriod = 429496730;\r
    }\r
\r
    //\r
    // Program the timer with the new count value\r
    //\r
    InitializeApicTimer (DivideValue, (UINT32)TimerCount, TRUE, LOCAL_APIC_TIMER_VECTOR);\r
\r
    //\r
    // Enable timer interrupt\r
    //\r
    EnableApicTimerInterrupt ();\r
  }\r
\r
  //\r
  // Save the new timer period\r
  //\r
  mTimerPeriod = TimerPeriod;\r
\r
  return EFI_SUCCESS;\r
}\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
\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
  @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
\r
  return EFI_SUCCESS;\r
}\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
\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
  EFI_TPL  OriginalTPL;\r
\r
  if (GetApicTimerInterruptState ()) {\r
    //\r
    // Invoke the registered handler\r
    //\r
    OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
\r
    if (mTimerNotifyFunction != NULL) {\r
      //\r
      // @bug : This does not handle missed timer interrupts\r
      //\r
      mTimerNotifyFunction (mTimerPeriod);\r
    }\r
\r
    gBS->RestoreTPL (OriginalTPL);\r
  } else {\r
    return EFI_UNSUPPORTED;\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Initialize the Timer Architectural Protocol driver\r
\r
  @param ImageHandle     ImageHandle of the loaded driver\r
  @param SystemTable     Pointer to the System Table\r
\r
  @retval EFI_SUCCESS            Timer Architectural Protocol created\r
  @retval EFI_OUT_OF_RESOURCES   Not enough resources available to initialize driver.\r
  @retval EFI_DEVICE_ERROR       A device error occurred attempting to initialize the driver.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
TimerDriverInitialize (\r
  IN EFI_HANDLE        ImageHandle,\r
  IN EFI_SYSTEM_TABLE  *SystemTable\r
  )\r
{\r
  EFI_STATUS  Status;\r
\r
  //\r
  // Initialize the pointer to our notify function.\r
  //\r
  mTimerNotifyFunction = NULL;\r
\r
  //\r
  // Make sure the Timer Architectural Protocol is not already installed in the system\r
  //\r
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);\r
\r
  //\r
  // Find the CPU architectural protocol.\r
  //\r
  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **)&mCpu);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // Force the timer to be disabled\r
  //\r
  Status = TimerDriverSetTimerPeriod (&mTimer, 0);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // Install interrupt handler for Local APIC Timer\r
  //\r
  Status = mCpu->RegisterInterruptHandler (\r
                   mCpu,\r
                   LOCAL_APIC_TIMER_VECTOR,\r
                   TimerInterruptHandler\r
                   );\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // Force the timer to be enabled at its default period\r
  //\r
  Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // Install the Timer Architectural Protocol onto a new handle\r
  //\r
  Status = gBS->InstallMultipleProtocolInterfaces (\r
                  &mTimerHandle,\r
                  &gEfiTimerArchProtocolGuid,\r
                  &mTimer,\r
                  NULL\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
\r
  return Status;\r
}\r
Commit	Line	Data
d668c8bc AP	1	/** @file\r
	2	Timer Architectural Protocol as defined in the DXE CIS\r
	3	\r
	4	Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>\r
	5	Copyright (c) 2019, Citrix Systems, Inc.\r
	6	\r
	7	SPDX-License-Identifier: BSD-2-Clause-Patent\r
	8	\r
	9	**/\r
	10	\r
	11	#include "XenTimerDxe.h"\r
	12	\r
	13	//\r
	14	// The handle onto which the Timer Architectural Protocol will be installed\r
	15	//\r
ac0a286f	16	EFI_HANDLE mTimerHandle = NULL;\r
d668c8bc AP	17	\r
	18	//\r
	19	// The Timer Architectural Protocol that this driver produces\r
	20	//\r
ac0a286f	21	EFI_TIMER_ARCH_PROTOCOL mTimer = {\r
d668c8bc AP	22	TimerDriverRegisterHandler,\r
	23	TimerDriverSetTimerPeriod,\r
	24	TimerDriverGetTimerPeriod,\r
	25	TimerDriverGenerateSoftInterrupt\r
	26	};\r
	27	\r
	28	//\r
	29	// Pointer to the CPU Architectural Protocol instance\r
	30	//\r
ac0a286f	31	EFI_CPU_ARCH_PROTOCOL *mCpu;\r
d668c8bc AP	32	\r
	33	//\r
	34	// The notification function to call on every timer interrupt.\r
	35	// A bug in the compiler prevents us from initializing this here.\r
	36	//\r
ac0a286f	37	EFI_TIMER_NOTIFY mTimerNotifyFunction;\r
d668c8bc AP	38	\r
	39	//\r
	40	// The current period of the timer interrupt\r
	41	//\r
ac0a286f	42	volatile UINT64 mTimerPeriod = 0;\r
d668c8bc AP	43	\r
	44	//\r
	45	// Worker Functions\r
	46	//\r
ac0a286f	47	\r
d668c8bc AP	48	/**\r
	49	Interrupt Handler.\r
	50	\r
	51	@param InterruptType The type of interrupt that occurred\r
	52	@param SystemContext A pointer to the system context when the interrupt occurred\r
	53	**/\r
	54	VOID\r
	55	EFIAPI\r
	56	TimerInterruptHandler (\r
ac0a286f MK	57	IN EFI_EXCEPTION_TYPE InterruptType,\r
ac0a286f MK	58	IN EFI_SYSTEM_CONTEXT SystemContext\r
d668c8bc AP	59	)\r
d668c8bc AP	60	{\r
ac0a286f	61	EFI_TPL OriginalTPL;\r
d668c8bc AP	62	\r
	63	OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
	64	\r
d668c8bc AP	65	if (mTimerNotifyFunction != NULL) {\r
	66	//\r
	67	// @bug : This does not handle missed timer interrupts\r
	68	//\r
	69	mTimerNotifyFunction (mTimerPeriod);\r
	70	}\r
	71	\r
	72	gBS->RestoreTPL (OriginalTPL);\r
239b50a8 ID	73	\r
	74	DisableInterrupts ();\r
	75	SendApicEoi ();\r
d668c8bc AP	76	}\r
	77	\r
	78	/**\r
	79	\r
	80	This function registers the handler NotifyFunction so it is called every time\r
	81	the timer interrupt fires. It also passes the amount of time since the last\r
	82	handler call to the NotifyFunction. If NotifyFunction is NULL, then the\r
	83	handler is unregistered. If the handler is registered, then EFI_SUCCESS is\r
	84	returned. If the CPU does not support registering a timer interrupt handler,\r
	85	then EFI_UNSUPPORTED is returned. If an attempt is made to register a handler\r
	86	when a handler is already registered, then EFI_ALREADY_STARTED is returned.\r
	87	If an attempt is made to unregister a handler when a handler is not registered,\r
	88	then EFI_INVALID_PARAMETER is returned. If an error occurs attempting to\r
	89	register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR\r
	90	is returned.\r
	91	\r
	92	\r
	93	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
	94	@param NotifyFunction The function to call when a timer interrupt fires. This\r
	95	function executes at TPL_HIGH_LEVEL. The DXE Core will\r
	96	register a handler for the timer interrupt, so it can know\r
	97	how much time has passed. This information is used to\r
	98	signal timer based events. NULL will unregister the handler.\r
	99	\r
	100	@retval EFI_SUCCESS The timer handler was registered.\r
	101	@retval EFI_UNSUPPORTED The platform does not support timer interrupts.\r
	102	@retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already\r
	103	registered.\r
	104	@retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not\r
	105	previously registered.\r
	106	@retval EFI_DEVICE_ERROR The timer handler could not be registered.\r
	107	\r
	108	**/\r
	109	EFI_STATUS\r
	110	EFIAPI\r
	111	TimerDriverRegisterHandler (\r
	112	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
	113	IN EFI_TIMER_NOTIFY NotifyFunction\r
	114	)\r
	115	{\r
	116	//\r
	117	// Check for invalid parameters\r
	118	//\r
ac0a286f	119	if ((NotifyFunction == NULL) && (mTimerNotifyFunction == NULL)) {\r
d668c8bc AP	120	return EFI_INVALID_PARAMETER;\r
	121	}\r
	122	\r
ac0a286f	123	if ((NotifyFunction != NULL) && (mTimerNotifyFunction != NULL)) {\r
d668c8bc AP	124	return EFI_ALREADY_STARTED;\r
	125	}\r
	126	\r
	127	mTimerNotifyFunction = NotifyFunction;\r
	128	\r
	129	return EFI_SUCCESS;\r
	130	}\r
	131	\r
	132	/**\r
	133	\r
	134	This function adjusts the period of timer interrupts to the value specified\r
	135	by TimerPeriod. If the timer period is updated, then the selected timer\r
	136	period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If\r
	137	the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.\r
	138	If an error occurs while attempting to update the timer period, then the\r
	139	timer hardware will be put back in its state prior to this call, and\r
	140	EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt\r
	141	is disabled. This is not the same as disabling the CPU's interrupts.\r
	142	Instead, it must either turn off the timer hardware, or it must adjust the\r
	143	interrupt controller so that a CPU interrupt is not generated when the timer\r
	144	interrupt fires.\r
	145	\r
	146	\r
	147	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
	148	@param TimerPeriod The rate to program the timer interrupt in 100 nS units. If\r
	149	the timer hardware is not programmable, then EFI_UNSUPPORTED is\r
	150	returned. If the timer is programmable, then the timer period\r
	151	will be rounded up to the nearest timer period that is supported\r
	152	by the timer hardware. If TimerPeriod is set to 0, then the\r
	153	timer interrupts will be disabled.\r
	154	\r
	155	@retval EFI_SUCCESS The timer period was changed.\r
	156	@retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.\r
	157	@retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.\r
	158	\r
	159	**/\r
	160	EFI_STATUS\r
	161	EFIAPI\r
	162	TimerDriverSetTimerPeriod (\r
	163	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
	164	IN UINT64 TimerPeriod\r
	165	)\r
	166	{\r
	167	UINT64 TimerCount;\r
	168	UINT32 TimerFrequency;\r
a9255967	169	UINT32 DivideValue = 1;\r
d668c8bc AP	170	\r
	171	if (TimerPeriod == 0) {\r
	172	//\r
	173	// Disable timer interrupt for a TimerPeriod of 0\r
	174	//\r
ac0a286f	175	DisableApicTimerInterrupt ();\r
d668c8bc	176	} else {\r
ac0a286f	177	TimerFrequency = PcdGet32 (PcdFSBClock) / DivideValue;\r
d668c8bc AP	178	\r
	179	//\r
	180	// Convert TimerPeriod into local APIC counts\r
	181	//\r
	182	// TimerPeriod is in 100ns\r
	183	// TimerPeriod/10000000 will be in seconds.\r
ac0a286f MK	184	TimerCount = DivU64x32 (\r
	185	MultU64x32 (TimerPeriod, TimerFrequency),\r
	186	10000000\r
	187	);\r
d668c8bc AP	188	\r
	189	// Check for overflow\r
	190	if (TimerCount > MAX_UINT32) {\r
	191	TimerCount = MAX_UINT32;\r
	192	/* TimerPeriod = (MAX_UINT32 / TimerFrequency) * 10000000; */\r
	193	TimerPeriod = 429496730;\r
	194	}\r
	195	\r
	196	//\r
	197	// Program the timer with the new count value\r
	198	//\r
ac0a286f	199	InitializeApicTimer (DivideValue, (UINT32)TimerCount, TRUE, LOCAL_APIC_TIMER_VECTOR);\r
d668c8bc AP	200	\r
	201	//\r
	202	// Enable timer interrupt\r
	203	//\r
ac0a286f	204	EnableApicTimerInterrupt ();\r
d668c8bc	205	}\r
ac0a286f	206	\r
d668c8bc AP	207	//\r
	208	// Save the new timer period\r
	209	//\r
	210	mTimerPeriod = TimerPeriod;\r
	211	\r
	212	return EFI_SUCCESS;\r
	213	}\r
	214	\r
	215	/**\r
	216	\r
	217	This function retrieves the period of timer interrupts in 100 ns units,\r
	218	returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod\r
	219	is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is\r
	220	returned, then the timer is currently disabled.\r
	221	\r
	222	\r
	223	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
	224	@param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If\r
	225	0 is returned, then the timer is currently disabled.\r
	226	\r
	227	@retval EFI_SUCCESS The timer period was returned in TimerPeriod.\r
	228	@retval EFI_INVALID_PARAMETER TimerPeriod is NULL.\r
	229	\r
	230	**/\r
	231	EFI_STATUS\r
	232	EFIAPI\r
	233	TimerDriverGetTimerPeriod (\r
ac0a286f MK	234	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
ac0a286f MK	235	OUT UINT64 *TimerPeriod\r
d668c8bc AP	236	)\r
	237	{\r
	238	if (TimerPeriod == NULL) {\r
	239	return EFI_INVALID_PARAMETER;\r
	240	}\r
	241	\r
	242	*TimerPeriod = mTimerPeriod;\r
	243	\r
	244	return EFI_SUCCESS;\r
	245	}\r
	246	\r
	247	/**\r
	248	\r
	249	This function generates a soft timer interrupt. If the platform does not support soft\r
	250	timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.\r
	251	If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()\r
	252	service, then a soft timer interrupt will be generated. If the timer interrupt is\r
	253	enabled when this service is called, then the registered handler will be invoked. The\r
	254	registered handler should not be able to distinguish a hardware-generated timer\r
	255	interrupt from a software-generated timer interrupt.\r
	256	\r
	257	\r
	258	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
	259	\r
	260	@retval EFI_SUCCESS The soft timer interrupt was generated.\r
	261	@retval EFI_UNSUPPORTED The platform does not support the generation of soft timer interrupts.\r
	262	\r
	263	**/\r
	264	EFI_STATUS\r
	265	EFIAPI\r
	266	TimerDriverGenerateSoftInterrupt (\r
	267	IN EFI_TIMER_ARCH_PROTOCOL *This\r
	268	)\r
	269	{\r
ac0a286f	270	EFI_TPL OriginalTPL;\r
d668c8bc	271	\r
ac0a286f	272	if (GetApicTimerInterruptState ()) {\r
d668c8bc AP	273	//\r
	274	// Invoke the registered handler\r
	275	//\r
	276	OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
	277	\r
	278	if (mTimerNotifyFunction != NULL) {\r
	279	//\r
	280	// @bug : This does not handle missed timer interrupts\r
	281	//\r
	282	mTimerNotifyFunction (mTimerPeriod);\r
	283	}\r
	284	\r
	285	gBS->RestoreTPL (OriginalTPL);\r
	286	} else {\r
	287	return EFI_UNSUPPORTED;\r
	288	}\r
	289	\r
	290	return EFI_SUCCESS;\r
	291	}\r
	292	\r
	293	/**\r
	294	Initialize the Timer Architectural Protocol driver\r
	295	\r
	296	@param ImageHandle ImageHandle of the loaded driver\r
	297	@param SystemTable Pointer to the System Table\r
	298	\r
	299	@retval EFI_SUCCESS Timer Architectural Protocol created\r
	300	@retval EFI_OUT_OF_RESOURCES Not enough resources available to initialize driver.\r
	301	@retval EFI_DEVICE_ERROR A device error occurred attempting to initialize the driver.\r
	302	\r
	303	**/\r
	304	EFI_STATUS\r
	305	EFIAPI\r
	306	TimerDriverInitialize (\r
	307	IN EFI_HANDLE ImageHandle,\r
	308	IN EFI_SYSTEM_TABLE *SystemTable\r
	309	)\r
	310	{\r
	311	EFI_STATUS Status;\r
	312	\r
	313	//\r
	314	// Initialize the pointer to our notify function.\r
	315	//\r
	316	mTimerNotifyFunction = NULL;\r
	317	\r
	318	//\r
	319	// Make sure the Timer Architectural Protocol is not already installed in the system\r
	320	//\r
	321	ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);\r
	322	\r
	323	//\r
	324	// Find the CPU architectural protocol.\r
	325	//\r
ac0a286f	326	Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **)&mCpu);\r
d668c8bc AP	327	ASSERT_EFI_ERROR (Status);\r
	328	\r
	329	//\r
	330	// Force the timer to be disabled\r
	331	//\r
	332	Status = TimerDriverSetTimerPeriod (&mTimer, 0);\r
	333	ASSERT_EFI_ERROR (Status);\r
	334	\r
	335	//\r
	336	// Install interrupt handler for Local APIC Timer\r
	337	//\r
ac0a286f MK	338	Status = mCpu->RegisterInterruptHandler (\r
	339	mCpu,\r
	340	LOCAL_APIC_TIMER_VECTOR,\r
	341	TimerInterruptHandler\r
	342	);\r
d668c8bc AP	343	ASSERT_EFI_ERROR (Status);\r
	344	\r
	345	//\r
	346	// Force the timer to be enabled at its default period\r
	347	//\r
	348	Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);\r
	349	ASSERT_EFI_ERROR (Status);\r
	350	\r
	351	//\r
	352	// Install the Timer Architectural Protocol onto a new handle\r
	353	//\r
	354	Status = gBS->InstallMultipleProtocolInterfaces (\r
	355	&mTimerHandle,\r
ac0a286f MK	356	&gEfiTimerArchProtocolGuid,\r
ac0a286f MK	357	&mTimer,\r
d668c8bc AP	358	NULL\r
	359	);\r
	360	ASSERT_EFI_ERROR (Status);\r
	361	\r
	362	return Status;\r
	363	}\r