[mirror_edk2.git] / InOsEmuPkg / TimerDxe / Timer.c

/*++ @file\r
  Emu Emulation Timer Architectural Protocol Driver as defined in DXE CIS\r
\r
  This Timer module uses an Emu Thread to simulate the timer-tick driven\r
  timer service.  In the future, the Thread creation should possibly be\r
  abstracted by the CPU architectural protocol\r
\r
Copyright (c) 2004, Intel Corporation. All rights reserved.<BR>\r
Portions copyright (c) 2010 - 2011, Apple Inc. All rights reserved.\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
#include <Protocol/Timer.h>\r
#include <Protocol/Cpu.h>\r
#include "Timer.h"\r
#include <Library/BaseLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/UefiLib.h>\r
#include <Library/UefiDriverEntryPoint.h>\r
#include <Library/MemoryAllocationLib.h>\r
#include <Library/UefiBootServicesTableLib.h>\r
#include <Library/EmuThunkLib.h>\r
\r
//\r
// Pointer to the CPU Architectural Protocol instance\r
//\r
EFI_CPU_ARCH_PROTOCOL   *mCpu;\r
\r
//\r
// The Timer Architectural Protocol that this driver produces\r
//\r
EFI_TIMER_ARCH_PROTOCOL mTimer = {\r
  EmuTimerDriverRegisterHandler,\r
  EmuTimerDriverSetTimerPeriod,\r
  EmuTimerDriverGetTimerPeriod,\r
  EmuTimerDriverGenerateSoftInterrupt\r
};\r
\r
//\r
// The notification function to call on every timer interrupt\r
//\r
EFI_TIMER_NOTIFY        mTimerNotifyFunction = NULL;\r
\r
//\r
// The current period of the timer interrupt\r
//\r
UINT64                  mTimerPeriodMs;\r
\r
\r
VOID\r
EFIAPI\r
TimerCallback (UINT64 DeltaMs)\r
{\r
  EFI_TPL           OriginalTPL;\r
  EFI_TIMER_NOTIFY  CallbackFunction;\r
\r
\r
  OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
\r
  if (OriginalTPL < TPL_HIGH_LEVEL) {\r
    CallbackFunction = mTimerNotifyFunction;\r
\r
    //\r
    // Only invoke the callback function if a Non-NULL handler has been\r
    // registered. Assume all other handlers are legal.\r
    //\r
    if (CallbackFunction != NULL) {\r
      CallbackFunction ((UINT64) (DeltaMs * 10000));\r
    }\r
  }\r
\r
  gBS->RestoreTPL (OriginalTPL);\r
\r
}\r
\r
EFI_STATUS\r
EFIAPI\r
EmuTimerDriverRegisterHandler (\r
  IN EFI_TIMER_ARCH_PROTOCOL           *This,\r
  IN EFI_TIMER_NOTIFY                  NotifyFunction\r
  )\r
/*++\r
\r
Routine Description:\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
Arguments:\r
\r
  This           - The EFI_TIMER_ARCH_PROTOCOL instance.\r
\r
  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
Returns:\r
\r
  EFI_SUCCESS           - The timer handler was registered.\r
\r
  EFI_UNSUPPORTED       - The platform does not support timer interrupts.\r
\r
  EFI_ALREADY_STARTED   - NotifyFunction is not NULL, and a handler is already\r
                          registered.\r
\r
  EFI_INVALID_PARAMETER - NotifyFunction is NULL, and a handler was not\r
                          previously registered.\r
\r
  EFI_DEVICE_ERROR      - The timer handler could not be registered.\r
\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
  if (NotifyFunction == NULL) {\r
    /* Disable timer.  */\r
    gEmuThunk->SetTimer (0, TimerCallback);\r
  } else if (mTimerNotifyFunction == NULL) {\r
    /* Enable Timer.  */\r
    gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);\r
  }\r
  mTimerNotifyFunction = NotifyFunction;\r
\r
  return EFI_SUCCESS;\r
}\r
\r
EFI_STATUS\r
EFIAPI\r
EmuTimerDriverSetTimerPeriod (\r
  IN EFI_TIMER_ARCH_PROTOCOL  *This,\r
  IN UINT64                   TimerPeriod\r
  )\r
/*++\r
\r
Routine Description:\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
Arguments:\r
\r
  This        - The EFI_TIMER_ARCH_PROTOCOL instance.\r
\r
  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
Returns:\r
\r
  EFI_SUCCESS      - The timer period was changed.\r
\r
  EFI_UNSUPPORTED  - The platform cannot change the period of the timer interrupt.\r
\r
  EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.\r
\r
**/\r
{\r
\r
  //\r
  // If TimerPeriod is 0, then the timer thread should be canceled\r
  // If the TimerPeriod is valid, then create and/or adjust the period of the timer thread\r
  //\r
  if (TimerPeriod == 0\r
      || ((TimerPeriod > TIMER_MINIMUM_VALUE)\r
    && (TimerPeriod < TIMER_MAXIMUM_VALUE))) {\r
    mTimerPeriodMs = DivU64x32 (TimerPeriod + 5000, 10000);\r
\r
    gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
\r
EFI_STATUS\r
EFIAPI\r
EmuTimerDriverGetTimerPeriod (\r
  IN EFI_TIMER_ARCH_PROTOCOL            *This,\r
  OUT UINT64                            *TimerPeriod\r
  )\r
/*++\r
\r
Routine Description:\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
Arguments:\r
\r
  This        - The EFI_TIMER_ARCH_PROTOCOL instance.\r
\r
  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
Returns:\r
\r
  EFI_SUCCESS           - The timer period was returned in TimerPeriod.\r
\r
  EFI_INVALID_PARAMETER - TimerPeriod is NULL.\r
\r
**/\r
{\r
  if (TimerPeriod == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  *TimerPeriod = mTimerPeriodMs * 10000;\r
\r
  return EFI_SUCCESS;\r
}\r
\r
EFI_STATUS\r
EFIAPI\r
EmuTimerDriverGenerateSoftInterrupt (\r
  IN EFI_TIMER_ARCH_PROTOCOL  *This\r
  )\r
/*++\r
\r
Routine Description:\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
Arguments:\r
\r
  This  -  The EFI_TIMER_ARCH_PROTOCOL instance.\r
\r
Returns:\r
\r
  EFI_SUCCESS       - The soft timer interrupt was generated.\r
\r
  EFI_UNSUPPORTEDT  - The platform does not support the generation of soft timer interrupts.\r
\r
**/\r
{\r
  return EFI_UNSUPPORTED;\r
}\r
\r
EFI_STATUS\r
EFIAPI\r
EmuTimerDriverInitialize (\r
  IN EFI_HANDLE        ImageHandle,\r
  IN EFI_SYSTEM_TABLE  *SystemTable\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  Initialize the Timer Architectural Protocol driver\r
\r
Arguments:\r
\r
  ImageHandle - ImageHandle of the loaded driver\r
\r
  SystemTable - Pointer to the System Table\r
\r
Returns:\r
\r
  EFI_SUCCESS           - Timer Architectural Protocol created\r
\r
  EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.\r
\r
  EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.\r
\r
**/\r
{\r
  EFI_STATUS  Status;\r
  EFI_HANDLE  Handle;\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
  // Get the CPU Architectural Protocol instance\r
  //\r
  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (void *)&mCpu);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // Install the Timer Architectural Protocol onto a new handle\r
  //\r
  Handle = NULL;\r
  Status = gBS->InstallProtocolInterface (\r
                  &Handle,\r
                  &gEfiTimerArchProtocolGuid,\r
                  EFI_NATIVE_INTERFACE,\r
                  &mTimer\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  //\r
  // Start the timer thread at the default timer period\r
  //\r
  Status = mTimer.SetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
Commit	Line	Data
949f388f	1	/*++ @file\r
	2	Emu Emulation Timer Architectural Protocol Driver as defined in DXE CIS\r
	3	\r
	4	This Timer module uses an Emu Thread to simulate the timer-tick driven\r
	5	timer service. In the future, the Thread creation should possibly be\r
	6	abstracted by the CPU architectural protocol\r
	7	\r
	8	Copyright (c) 2004, Intel Corporation. All rights reserved.<BR>\r
	9	Portions copyright (c) 2010 - 2011, Apple Inc. All rights reserved.\r
	10	This program and the accompanying materials\r
	11	are licensed and made available under the terms and conditions of the BSD License\r
	12	which accompanies this distribution. The full text of the license may be found at\r
	13	http://opensource.org/licenses/bsd-license.php\r
	14	\r
	15	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	16	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	17	\r
	18	\r
	19	**/\r
	20	\r
	21	#include "PiDxe.h"\r
	22	#include <Protocol/Timer.h>\r
	23	#include <Protocol/Cpu.h>\r
	24	#include "Timer.h"\r
	25	#include <Library/BaseLib.h>\r
	26	#include <Library/DebugLib.h>\r
	27	#include <Library/UefiLib.h>\r
	28	#include <Library/UefiDriverEntryPoint.h>\r
	29	#include <Library/MemoryAllocationLib.h>\r
	30	#include <Library/UefiBootServicesTableLib.h>\r
	31	#include <Library/EmuThunkLib.h>\r
	32	\r
	33	//\r
	34	// Pointer to the CPU Architectural Protocol instance\r
	35	//\r
	36	EFI_CPU_ARCH_PROTOCOL *mCpu;\r
	37	\r
	38	//\r
	39	// The Timer Architectural Protocol that this driver produces\r
	40	//\r
	41	EFI_TIMER_ARCH_PROTOCOL mTimer = {\r
	42	EmuTimerDriverRegisterHandler,\r
	43	EmuTimerDriverSetTimerPeriod,\r
	44	EmuTimerDriverGetTimerPeriod,\r
	45	EmuTimerDriverGenerateSoftInterrupt\r
	46	};\r
	47	\r
	48	//\r
	49	// The notification function to call on every timer interrupt\r
	50	//\r
	51	EFI_TIMER_NOTIFY mTimerNotifyFunction = NULL;\r
	52	\r
	53	//\r
	54	// The current period of the timer interrupt\r
	55	//\r
	56	UINT64 mTimerPeriodMs;\r
	57	\r
	58	\r
	59	VOID\r
	60	EFIAPI\r
	61	TimerCallback (UINT64 DeltaMs)\r
	62	{\r
	63	EFI_TPL OriginalTPL;\r
	64	EFI_TIMER_NOTIFY CallbackFunction;\r
65	\r
66	\r
67	OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
68	\r
69	if (OriginalTPL < TPL_HIGH_LEVEL) {\r
70	CallbackFunction = mTimerNotifyFunction;\r
71	\r
72	//\r
73	// Only invoke the callback function if a Non-NULL handler has been\r
74	// registered. Assume all other handlers are legal.\r
75	//\r
76	if (CallbackFunction != NULL) {\r
77	CallbackFunction ((UINT64) (DeltaMs * 10000));\r
78	}\r
79	}\r
80	\r
81	gBS->RestoreTPL (OriginalTPL);\r
82	\r
83	}\r
84	\r
85	EFI_STATUS\r
86	EFIAPI\r
87	EmuTimerDriverRegisterHandler (\r
88	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
89	IN EFI_TIMER_NOTIFY NotifyFunction\r
90	)\r
91	/*++\r
92	\r
93	Routine Description:\r
94	\r
95	This function registers the handler NotifyFunction so it is called every time\r
96	the timer interrupt fires. It also passes the amount of time since the last\r
97	handler call to the NotifyFunction. If NotifyFunction is NULL, then the\r
98	handler is unregistered. If the handler is registered, then EFI_SUCCESS is\r
99	returned. If the CPU does not support registering a timer interrupt handler,\r
100	then EFI_UNSUPPORTED is returned. If an attempt is made to register a handler\r
101	when a handler is already registered, then EFI_ALREADY_STARTED is returned.\r
102	If an attempt is made to unregister a handler when a handler is not registered,\r
103	then EFI_INVALID_PARAMETER is returned. If an error occurs attempting to\r
104	register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR\r
105	is returned.\r
106	\r
107	Arguments:\r
108	\r
109	This - The EFI_TIMER_ARCH_PROTOCOL instance.\r
110	\r
111	NotifyFunction - The function to call when a timer interrupt fires. This\r
112	function executes at TPL_HIGH_LEVEL. The DXE Core will\r
113	register a handler for the timer interrupt, so it can know\r
114	how much time has passed. This information is used to\r
115	signal timer based events. NULL will unregister the handler.\r
116	\r
117	Returns:\r
118	\r
119	EFI_SUCCESS - The timer handler was registered.\r
120	\r
121	EFI_UNSUPPORTED - The platform does not support timer interrupts.\r
122	\r
123	EFI_ALREADY_STARTED - NotifyFunction is not NULL, and a handler is already\r
124	registered.\r
125	\r
126	EFI_INVALID_PARAMETER - NotifyFunction is NULL, and a handler was not\r
127	previously registered.\r
128	\r
129	EFI_DEVICE_ERROR - The timer handler could not be registered.\r
130	\r
131	**/\r
132	{\r
133	//\r
134	// Check for invalid parameters\r
135	//\r
136	if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) {\r
137	return EFI_INVALID_PARAMETER;\r
138	}\r
139	\r
140	if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {\r
141	return EFI_ALREADY_STARTED;\r
142	}\r
143	\r
144	if (NotifyFunction == NULL) {\r
145	/* Disable timer. */\r
146	gEmuThunk->SetTimer (0, TimerCallback);\r
147	} else if (mTimerNotifyFunction == NULL) {\r
148	/* Enable Timer. */\r
149	gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);\r
150	}\r
151	mTimerNotifyFunction = NotifyFunction;\r
152	\r
153	return EFI_SUCCESS;\r
154	}\r
155	\r
156	EFI_STATUS\r
157	EFIAPI\r
158	EmuTimerDriverSetTimerPeriod (\r
159	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
160	IN UINT64 TimerPeriod\r
161	)\r
162	/*++\r
163	\r
164	Routine Description:\r
165	\r
166	This function adjusts the period of timer interrupts to the value specified\r
167	by TimerPeriod. If the timer period is updated, then the selected timer\r
168	period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If\r
169	the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.\r
170	If an error occurs while attempting to update the timer period, then the\r
171	timer hardware will be put back in its state prior to this call, and\r
172	EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt\r
173	is disabled. This is not the same as disabling the CPU's interrupts.\r
174	Instead, it must either turn off the timer hardware, or it must adjust the\r
175	interrupt controller so that a CPU interrupt is not generated when the timer\r
176	interrupt fires.\r
177	\r
178	Arguments:\r
179	\r
180	This - The EFI_TIMER_ARCH_PROTOCOL instance.\r
181	\r
182	TimerPeriod - The rate to program the timer interrupt in 100 nS units. If\r
183	the timer hardware is not programmable, then EFI_UNSUPPORTED is\r
184	returned. If the timer is programmable, then the timer period\r
185	will be rounded up to the nearest timer period that is supported\r
186	by the timer hardware. If TimerPeriod is set to 0, then the\r
187	timer interrupts will be disabled.\r
188	\r
189	Returns:\r
190	\r
191	EFI_SUCCESS - The timer period was changed.\r
192	\r
193	EFI_UNSUPPORTED - The platform cannot change the period of the timer interrupt.\r
194	\r
195	EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.\r
196	\r
197	**/\r
198	{\r
199	\r
200	//\r
201	// If TimerPeriod is 0, then the timer thread should be canceled\r
202	// If the TimerPeriod is valid, then create and/or adjust the period of the timer thread\r
203	//\r
204	if (TimerPeriod == 0\r
205	\|\| ((TimerPeriod > TIMER_MINIMUM_VALUE)\r
206	&& (TimerPeriod < TIMER_MAXIMUM_VALUE))) {\r
207	mTimerPeriodMs = DivU64x32 (TimerPeriod + 5000, 10000);\r
208	\r
209	gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);\r
210	}\r
211	\r
212	return EFI_SUCCESS;\r
213	}\r
214	\r
215	EFI_STATUS\r
216	EFIAPI\r
217	EmuTimerDriverGetTimerPeriod (\r
218	IN EFI_TIMER_ARCH_PROTOCOL *This,\r
219	OUT UINT64 *TimerPeriod\r
220	)\r
221	/*++\r
222	\r
223	Routine Description:\r
224	\r
225	This function retrieves the period of timer interrupts in 100 ns units,\r
226	returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod\r
227	is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is\r
228	returned, then the timer is currently disabled.\r
229	\r
230	Arguments:\r
231	\r
232	This - The EFI_TIMER_ARCH_PROTOCOL instance.\r
233	\r
234	TimerPeriod - A pointer to the timer period to retrieve in 100 ns units. If\r
235	0 is returned, then the timer is currently disabled.\r
236	\r
237	Returns:\r
238	\r
239	EFI_SUCCESS - The timer period was returned in TimerPeriod.\r
240	\r
241	EFI_INVALID_PARAMETER - TimerPeriod is NULL.\r
242	\r
243	**/\r
244	{\r
245	if (TimerPeriod == NULL) {\r
246	return EFI_INVALID_PARAMETER;\r
247	}\r
248	\r
249	TimerPeriod = mTimerPeriodMs 10000;\r
250	\r
251	return EFI_SUCCESS;\r
252	}\r
253	\r
254	EFI_STATUS\r
255	EFIAPI\r
256	EmuTimerDriverGenerateSoftInterrupt (\r
257	IN EFI_TIMER_ARCH_PROTOCOL *This\r
258	)\r
259	/*++\r
260	\r
261	Routine Description:\r
262	\r
263	This function generates a soft timer interrupt. If the platform does not support soft\r
264	timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.\r
265	If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()\r
266	service, then a soft timer interrupt will be generated. If the timer interrupt is\r
267	enabled when this service is called, then the registered handler will be invoked. The\r
268	registered handler should not be able to distinguish a hardware-generated timer\r
269	interrupt from a software-generated timer interrupt.\r
270	\r
271	Arguments:\r
272	\r
273	This - The EFI_TIMER_ARCH_PROTOCOL instance.\r
274	\r
275	Returns:\r
276	\r
277	EFI_SUCCESS - The soft timer interrupt was generated.\r
278	\r
279	EFI_UNSUPPORTEDT - The platform does not support the generation of soft timer interrupts.\r
280	\r
281	**/\r
282	{\r
283	return EFI_UNSUPPORTED;\r
284	}\r
285	\r
286	EFI_STATUS\r
287	EFIAPI\r
288	EmuTimerDriverInitialize (\r
289	IN EFI_HANDLE ImageHandle,\r
290	IN EFI_SYSTEM_TABLE *SystemTable\r
291	)\r
292	/*++\r
293	\r
294	Routine Description:\r
295	\r
296	Initialize the Timer Architectural Protocol driver\r
297	\r
298	Arguments:\r
299	\r
300	ImageHandle - ImageHandle of the loaded driver\r
301	\r
302	SystemTable - Pointer to the System Table\r
303	\r
304	Returns:\r
305	\r
306	EFI_SUCCESS - Timer Architectural Protocol created\r
307	\r
308	EFI_OUT_OF_RESOURCES - Not enough resources available to initialize driver.\r
309	\r
310	EFI_DEVICE_ERROR - A device error occured attempting to initialize the driver.\r
311	\r
312	**/\r
313	{\r
314	EFI_STATUS Status;\r
315	EFI_HANDLE Handle;\r
316	\r
317	//\r
318	// Make sure the Timer Architectural Protocol is not already installed in the system\r
319	//\r
320	ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);\r
321	\r
322	//\r
323	// Get the CPU Architectural Protocol instance\r
324	//\r
325	Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (void *)&mCpu);\r
326	ASSERT_EFI_ERROR (Status);\r
327	\r
328	//\r
329	// Install the Timer Architectural Protocol onto a new handle\r
330	//\r
331	Handle = NULL;\r
332	Status = gBS->InstallProtocolInterface (\r
333	&Handle,\r
334	&gEfiTimerArchProtocolGuid,\r
335	EFI_NATIVE_INTERFACE,\r
336	&mTimer\r
337	);\r
338	if (EFI_ERROR (Status)) {\r
339	return Status;\r
340	}\r
341	\r
342	//\r
343	// Start the timer thread at the default timer period\r
344	//\r
345	Status = mTimer.SetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);\r
346	if (EFI_ERROR (Status)) {\r
347	return Status;\r
348	}\r
349	\r
350	return EFI_SUCCESS;\r
351	}\r