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

/** @file\r
*\r
*  Copyright (c) 2011-2012, ARM Limited. All rights reserved.\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/BaseLib.h>\r
#include <Library/BaseMemoryLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/IoLib.h>\r
#include <Library/PcdLib.h>\r
#include <Library/UefiBootServicesTableLib.h>\r
#include <Library/UefiRuntimeServicesTableLib.h>\r
#include <Library/UefiLib.h>\r
\r
#include <Protocol/WatchdogTimer.h>\r
#include <Drivers/SP805Watchdog.h>\r
\r
EFI_EVENT                           EfiExitBootServicesEvent = (EFI_EVENT)NULL;\r
\r
/**\r
  Make sure the SP805 registers are unlocked for writing.\r
\r
  Note: The SP805 Watchdog Timer supports locking of its registers,\r
  i.e. it inhibits all writes to avoid rogue software accidentally\r
  corrupting their contents.\r
**/\r
inline\r
VOID\r
SP805Unlock (\r
  VOID\r
  )\r
{\r
  if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_LOCKED ) {\r
    MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_SPECIAL_UNLOCK_CODE);\r
  }\r
}\r
\r
/**\r
  Make sure the SP805 registers are locked and can not be overwritten.\r
\r
  Note: The SP805 Watchdog Timer supports locking of its registers,\r
  i.e. it inhibits all writes to avoid rogue software accidentally\r
  corrupting their contents.\r
**/\r
inline\r
VOID\r
SP805Lock (\r
  VOID\r
  )\r
{\r
  if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_UNLOCKED ) {\r
    // To lock it, just write in any number (except the special unlock code).\r
    MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_LOCK_IS_LOCKED);\r
  }\r
}\r
\r
/**\r
  Stop the SP805 watchdog timer from counting down by disabling interrupts.\r
**/\r
inline\r
VOID\r
SP805Stop (\r
  VOID\r
  )\r
{\r
  // Disable interrupts\r
  if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) != 0 ) {\r
    MmioAnd32(SP805_WDOG_CONTROL_REG, ~SP805_WDOG_CTRL_INTEN);\r
  }\r
}\r
\r
/**\r
  Starts the SP805 counting down by enabling interrupts.\r
  The count down will start from the value stored in the Load register,\r
  not from the value where it was previously stopped.\r
**/\r
inline\r
VOID\r
SP805Start (\r
  VOID\r
  )\r
{\r
  // Enable interrupts\r
  if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) {\r
    MmioOr32(SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_INTEN);\r
  }\r
}\r
\r
/**\r
    On exiting boot services we must make sure the SP805 Watchdog Timer\r
    is stopped.\r
**/\r
VOID\r
EFIAPI\r
ExitBootServicesEvent (\r
  IN EFI_EVENT  Event,\r
  IN VOID       *Context\r
  )\r
{\r
  SP805Unlock();\r
  SP805Stop();\r
  SP805Lock();\r
}\r
\r
/**\r
  This function registers the handler NotifyFunction so it is called every time\r
  the watchdog timer expires.  It also passes the amount of time since the last\r
  handler call to the NotifyFunction.\r
  If NotifyFunction is not NULL and a handler is not already registered,\r
  then the new handler is registered and EFI_SUCCESS is returned.\r
  If NotifyFunction is NULL, and a handler is already registered,\r
  then that handler is unregistered.\r
  If an attempt is made to register a handler when a handler is already registered,\r
  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.\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 watchdog timer handler was registered.\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
\r
**/\r
EFI_STATUS\r
EFIAPI\r
SP805RegisterHandler (\r
  IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL   *This,\r
  IN EFI_WATCHDOG_TIMER_NOTIFY                NotifyFunction\r
  )\r
{\r
  // ERROR: This function is not supported.\r
  // The hardware watchdog will reset the board\r
  return EFI_INVALID_PARAMETER;\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
SP805SetTimerPeriod (\r
  IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL   *This,\r
  IN UINT64                                   TimerPeriod   // In 100ns units\r
  )\r
{\r
  EFI_STATUS  Status = EFI_SUCCESS;\r
  UINT64      Ticks64bit;\r
\r
  SP805Unlock();\r
\r
  if( TimerPeriod == 0 ) {\r
    // This is a watchdog stop request\r
    SP805Stop();\r
    goto EXIT;\r
  } else {\r
    // Calculate the Watchdog ticks required for a delay of (TimerTicks * 100) nanoseconds\r
    // The SP805 will count down to ZERO once, generate an interrupt and\r
    // then it will again reload the initial value and start again.\r
    // On the second time when it reaches ZERO, it will actually reset the board.\r
    // Therefore, we need to load half the required delay.\r
    //\r
    // WatchdogTicks = ((TimerPeriod * 100 * SP805_CLOCK_FREQUENCY) / 1GHz) / 2 ;\r
    //\r
    // i.e.:\r
    //\r
    // WatchdogTicks = (TimerPeriod * SP805_CLOCK_FREQUENCY) / 20 MHz ;\r
\r
    Ticks64bit = DivU64x32(MultU64x32(TimerPeriod, (UINTN)PcdGet32(PcdSP805WatchdogClockFrequencyInHz)), 20000000);\r
\r
    // The registers in the SP805 are only 32 bits\r
    if(Ticks64bit > (UINT64)0xFFFFFFFF) {\r
      // We could load the watchdog with the maximum supported value but\r
      // if a smaller value was requested, this could have the watchdog\r
      // triggering before it was intended.\r
      // Better generate an error to let the caller know.\r
      Status = EFI_DEVICE_ERROR;\r
      goto EXIT;\r
    }\r
\r
    // Update the watchdog with a 32-bit value.\r
    MmioWrite32(SP805_WDOG_LOAD_REG, (UINT32)Ticks64bit);\r
\r
    // Start the watchdog\r
    SP805Start();\r
  }\r
\r
  EXIT:\r
  // Ensure the watchdog is locked before exiting.\r
  SP805Lock();\r
  return Status;\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
SP805GetTimerPeriod (\r
  IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL   *This,\r
  OUT UINT64                                  *TimerPeriod\r
  )\r
{\r
  EFI_STATUS  Status = EFI_SUCCESS;\r
  UINT64      ReturnValue;\r
\r
  if (TimerPeriod == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  // Check if the watchdog is stopped\r
  if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) {\r
    // It is stopped, so return zero.\r
    ReturnValue = 0;\r
  } else {\r
    // Convert the Watchdog ticks into TimerPeriod\r
    // Ensure 64bit arithmetic throughout because the Watchdog ticks may already\r
    // be at the maximum 32 bit value and we still need to multiply that by 600.\r
    ReturnValue = MultU64x32( MmioRead32(SP805_WDOG_LOAD_REG), 600 );\r
  }\r
\r
  *TimerPeriod = ReturnValue;\r
\r
  return Status;\r
}\r
\r
/**\r
  Interface structure for the Watchdog Architectural Protocol.\r
\r
  @par Protocol Description:\r
  This protocol provides a service to set the amount of time to wait\r
  before firing the watchdog timer, and it also provides a service to\r
  register a handler that is invoked when the watchdog timer fires.\r
\r
  @par When the watchdog timer fires, control will be passed to a handler\r
  if one has been registered.  If no handler has been registered,\r
  or the registered handler returns, then the system will be\r
  reset by calling the Runtime Service ResetSystem().\r
\r
  @param RegisterHandler\r
  Registers a handler that will be called each time the\r
  watchdogtimer 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
  NOTE: If the watchdog resets the system in hardware, then\r
        this function will not have any chance of executing.\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
  @param GetTimerPeriod\r
  Retrieves the period of the timer interrupt in 100 nS units.\r
\r
**/\r
EFI_WATCHDOG_TIMER_ARCH_PROTOCOL    gWatchdogTimer = {\r
  (EFI_WATCHDOG_TIMER_REGISTER_HANDLER) SP805RegisterHandler,\r
  (EFI_WATCHDOG_TIMER_SET_TIMER_PERIOD) SP805SetTimerPeriod,\r
  (EFI_WATCHDOG_TIMER_GET_TIMER_PERIOD) SP805GetTimerPeriod\r
};\r
\r
/**\r
  Initialize the state information for the Watchdog Timer Architectural Protocol.\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
SP805Initialize (\r
  IN EFI_HANDLE         ImageHandle,\r
  IN EFI_SYSTEM_TABLE   *SystemTable\r
  )\r
{\r
  EFI_STATUS  Status;\r
  EFI_HANDLE  Handle;\r
\r
  // Unlock access to the SP805 registers\r
  SP805Unlock ();\r
\r
  // Stop the watchdog from triggering unexpectedly\r
  SP805Stop ();\r
\r
  // Set the watchdog to reset the board when triggered\r
  if ((MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_RESEN) == 0) {\r
    MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_RESEN);\r
  }\r
\r
  // Prohibit any rogue access to SP805 registers\r
  SP805Lock();\r
  \r
  //\r
  // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.\r
  // This will avoid conflicts with the universal watchdog\r
  //\r
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);\r
\r
  // Register for an ExitBootServicesEvent\r
  Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent);\r
  if (EFI_ERROR(Status)) {\r
    Status = EFI_OUT_OF_RESOURCES;\r
    goto EXIT;\r
  }\r
\r
  // Install the Timer Architectural Protocol onto a new handle\r
  Handle = NULL;\r
  Status = gBS->InstallMultipleProtocolInterfaces(\r
                  &Handle,\r
                  &gEfiWatchdogTimerArchProtocolGuid, &gWatchdogTimer,\r
                  NULL\r
                  );\r
  if (EFI_ERROR(Status)) {\r
    Status = EFI_OUT_OF_RESOURCES;\r
    goto EXIT;\r
  }\r
\r
EXIT:\r
  if(EFI_ERROR(Status)) {\r
    // The watchdog failed to initialize\r
    ASSERT(FALSE);\r
  }\r
  return Status;\r
}\r
Commit	Line	Data
1e57a462	1	/** @file\r
	2	*\r
	3	* Copyright (c) 2011-2012, ARM Limited. All rights reserved.\r
	4	*\r
	5	* This program and the accompanying materials\r
	6	* are licensed and made available under the terms and conditions of the BSD License\r
	7	* which accompanies this distribution. The full text of the license may be found at\r
	8	* http://opensource.org/licenses/bsd-license.php\r
	9	*\r
	10	* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	11	* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	12	*\r
	13	**/\r
	14	\r
	15	\r
	16	#include <PiDxe.h>\r
	17	\r
	18	#include <Library/BaseLib.h>\r
	19	#include <Library/BaseMemoryLib.h>\r
	20	#include <Library/DebugLib.h>\r
	21	#include <Library/IoLib.h>\r
	22	#include <Library/PcdLib.h>\r
	23	#include <Library/UefiBootServicesTableLib.h>\r
	24	#include <Library/UefiRuntimeServicesTableLib.h>\r
	25	#include <Library/UefiLib.h>\r
	26	\r
	27	#include <Protocol/WatchdogTimer.h>\r
	28	#include <Drivers/SP805Watchdog.h>\r
	29	\r
	30	EFI_EVENT EfiExitBootServicesEvent = (EFI_EVENT)NULL;\r
	31	\r
	32	/**\r
	33	Make sure the SP805 registers are unlocked for writing.\r
	34	\r
	35	Note: The SP805 Watchdog Timer supports locking of its registers,\r
	36	i.e. it inhibits all writes to avoid rogue software accidentally\r
	37	corrupting their contents.\r
	38	**/\r
	39	inline\r
	40	VOID\r
	41	SP805Unlock (\r
	42	VOID\r
	43	)\r
	44	{\r
	45	if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_LOCKED ) {\r
	46	MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_SPECIAL_UNLOCK_CODE);\r
	47	}\r
	48	}\r
	49	\r
	50	/**\r
	51	Make sure the SP805 registers are locked and can not be overwritten.\r
	52	\r
	53	Note: The SP805 Watchdog Timer supports locking of its registers,\r
	54	i.e. it inhibits all writes to avoid rogue software accidentally\r
	55	corrupting their contents.\r
	56	**/\r
	57	inline\r
	58	VOID\r
	59	SP805Lock (\r
	60	VOID\r
	61	)\r
	62	{\r
	63	if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_UNLOCKED ) {\r
	64	// To lock it, just write in any number (except the special unlock code).\r
65	MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_LOCK_IS_LOCKED);\r
66	}\r
67	}\r
68	\r
69	/**\r
70	Stop the SP805 watchdog timer from counting down by disabling interrupts.\r
71	**/\r
72	inline\r
73	VOID\r
74	SP805Stop (\r
75	VOID\r
76	)\r
77	{\r
78	// Disable interrupts\r
79	if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) != 0 ) {\r
80	MmioAnd32(SP805_WDOG_CONTROL_REG, ~SP805_WDOG_CTRL_INTEN);\r
81	}\r
82	}\r
83	\r
84	/**\r
85	Starts the SP805 counting down by enabling interrupts.\r
86	The count down will start from the value stored in the Load register,\r
87	not from the value where it was previously stopped.\r
88	**/\r
89	inline\r
90	VOID\r
91	SP805Start (\r
92	VOID\r
93	)\r
94	{\r
95	// Enable interrupts\r
96	if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) {\r
97	MmioOr32(SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_INTEN);\r
98	}\r
99	}\r
100	\r
101	/**\r
102	On exiting boot services we must make sure the SP805 Watchdog Timer\r
103	is stopped.\r
104	**/\r
105	VOID\r
106	EFIAPI\r
107	ExitBootServicesEvent (\r
108	IN EFI_EVENT Event,\r
109	IN VOID *Context\r
110	)\r
111	{\r
112	SP805Unlock();\r
113	SP805Stop();\r
114	SP805Lock();\r
115	}\r
116	\r
117	/**\r
118	This function registers the handler NotifyFunction so it is called every time\r
119	the watchdog timer expires. It also passes the amount of time since the last\r
120	handler call to the NotifyFunction.\r
121	If NotifyFunction is not NULL and a handler is not already registered,\r
122	then the new handler is registered and EFI_SUCCESS is returned.\r
123	If NotifyFunction is NULL, and a handler is already registered,\r
124	then that handler is unregistered.\r
125	If an attempt is made to register a handler when a handler is already registered,\r
126	then EFI_ALREADY_STARTED is returned.\r
127	If an attempt is made to unregister a handler when a handler is not registered,\r
128	then EFI_INVALID_PARAMETER is returned.\r
129	\r
130	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
131	@param NotifyFunction The function to call when a timer interrupt fires. This\r
132	function executes at TPL_HIGH_LEVEL. The DXE Core will\r
133	register a handler for the timer interrupt, so it can know\r
134	how much time has passed. This information is used to\r
135	signal timer based events. NULL will unregister the handler.\r
136	\r
137	@retval EFI_SUCCESS The watchdog timer handler was registered.\r
138	@retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already\r
139	registered.\r
140	@retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not\r
141	previously registered.\r
142	\r
143	**/\r
144	EFI_STATUS\r
145	EFIAPI\r
146	SP805RegisterHandler (\r
147	IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,\r
148	IN EFI_WATCHDOG_TIMER_NOTIFY NotifyFunction\r
149	)\r
150	{\r
151	// ERROR: This function is not supported.\r
152	// The hardware watchdog will reset the board\r
153	return EFI_INVALID_PARAMETER;\r
154	}\r
155	\r
156	/**\r
157	\r
158	This function adjusts the period of timer interrupts to the value specified\r
159	by TimerPeriod. If the timer period is updated, then the selected timer\r
160	period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If\r
161	the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.\r
162	If an error occurs while attempting to update the timer period, then the\r
163	timer hardware will be put back in its state prior to this call, and\r
164	EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt\r
165	is disabled. This is not the same as disabling the CPU's interrupts.\r
166	Instead, it must either turn off the timer hardware, or it must adjust the\r
167	interrupt controller so that a CPU interrupt is not generated when the timer\r
168	interrupt fires.\r
169	\r
170	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
171	@param TimerPeriod The rate to program the timer interrupt in 100 nS units. If\r
172	the timer hardware is not programmable, then EFI_UNSUPPORTED is\r
173	returned. If the timer is programmable, then the timer period\r
174	will be rounded up to the nearest timer period that is supported\r
175	by the timer hardware. If TimerPeriod is set to 0, then the\r
176	timer interrupts will be disabled.\r
177	\r
178	\r
179	@retval EFI_SUCCESS The timer period was changed.\r
180	@retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.\r
181	@retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.\r
182	\r
183	**/\r
184	EFI_STATUS\r
185	EFIAPI\r
186	SP805SetTimerPeriod (\r
187	IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,\r
188	IN UINT64 TimerPeriod // In 100ns units\r
189	)\r
190	{\r
191	EFI_STATUS Status = EFI_SUCCESS;\r
192	UINT64 Ticks64bit;\r
193	\r
194	SP805Unlock();\r
195	\r
196	if( TimerPeriod == 0 ) {\r
197	// This is a watchdog stop request\r
198	SP805Stop();\r
199	goto EXIT;\r
200	} else {\r
201	// Calculate the Watchdog ticks required for a delay of (TimerTicks * 100) nanoseconds\r
202	// The SP805 will count down to ZERO once, generate an interrupt and\r
203	// then it will again reload the initial value and start again.\r
204	// On the second time when it reaches ZERO, it will actually reset the board.\r
205	// Therefore, we need to load half the required delay.\r
206	//\r
207	// WatchdogTicks = ((TimerPeriod * 100 * SP805_CLOCK_FREQUENCY) / 1GHz) / 2 ;\r
208	//\r
209	// i.e.:\r
210	//\r
211	// WatchdogTicks = (TimerPeriod * SP805_CLOCK_FREQUENCY) / 20 MHz ;\r
212	\r
213	Ticks64bit = DivU64x32(MultU64x32(TimerPeriod, (UINTN)PcdGet32(PcdSP805WatchdogClockFrequencyInHz)), 20000000);\r
214	\r
215	// The registers in the SP805 are only 32 bits\r
216	if(Ticks64bit > (UINT64)0xFFFFFFFF) {\r
217	// We could load the watchdog with the maximum supported value but\r
218	// if a smaller value was requested, this could have the watchdog\r
219	// triggering before it was intended.\r
220	// Better generate an error to let the caller know.\r
221	Status = EFI_DEVICE_ERROR;\r
222	goto EXIT;\r
223	}\r
224	\r
225	// Update the watchdog with a 32-bit value.\r
226	MmioWrite32(SP805_WDOG_LOAD_REG, (UINT32)Ticks64bit);\r
227	\r
228	// Start the watchdog\r
229	SP805Start();\r
230	}\r
231	\r
232	EXIT:\r
233	// Ensure the watchdog is locked before exiting.\r
234	SP805Lock();\r
235	return Status;\r
236	}\r
237	\r
238	/**\r
239	This function retrieves the period of timer interrupts in 100 ns units,\r
240	returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod\r
241	is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is\r
242	returned, then the timer is currently disabled.\r
243	\r
244	@param This The EFI_TIMER_ARCH_PROTOCOL instance.\r
245	@param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If\r
246	0 is returned, then the timer is currently disabled.\r
247	\r
248	\r
249	@retval EFI_SUCCESS The timer period was returned in TimerPeriod.\r
250	@retval EFI_INVALID_PARAMETER TimerPeriod is NULL.\r
251	\r
252	**/\r
253	EFI_STATUS\r
254	EFIAPI\r
255	SP805GetTimerPeriod (\r
256	IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,\r
257	OUT UINT64 *TimerPeriod\r
258	)\r
259	{\r
260	EFI_STATUS Status = EFI_SUCCESS;\r
261	UINT64 ReturnValue;\r
262	\r
263	if (TimerPeriod == NULL) {\r
264	return EFI_INVALID_PARAMETER;\r
265	}\r
266	\r
267	// Check if the watchdog is stopped\r
268	if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) {\r
269	// It is stopped, so return zero.\r
270	ReturnValue = 0;\r
271	} else {\r
272	// Convert the Watchdog ticks into TimerPeriod\r
273	// Ensure 64bit arithmetic throughout because the Watchdog ticks may already\r
274	// be at the maximum 32 bit value and we still need to multiply that by 600.\r
275	ReturnValue = MultU64x32( MmioRead32(SP805_WDOG_LOAD_REG), 600 );\r
276	}\r
277	\r
278	*TimerPeriod = ReturnValue;\r
279	\r
280	return Status;\r
281	}\r
282	\r
283	/**\r
284	Interface structure for the Watchdog Architectural Protocol.\r
285	\r
286	@par Protocol Description:\r
287	This protocol provides a service to set the amount of time to wait\r
288	before firing the watchdog timer, and it also provides a service to\r
289	register a handler that is invoked when the watchdog timer fires.\r
290	\r
291	@par When the watchdog timer fires, control will be passed to a handler\r
292	if one has been registered. If no handler has been registered,\r
293	or the registered handler returns, then the system will be\r
294	reset by calling the Runtime Service ResetSystem().\r
295	\r
296	@param RegisterHandler\r
297	Registers a handler that will be called each time the\r
298	watchdogtimer interrupt fires. TimerPeriod defines the minimum\r
299	time between timer interrupts, so TimerPeriod will also\r
300	be the minimum time between calls to the registered\r
301	handler.\r
302	NOTE: If the watchdog resets the system in hardware, then\r
303	this function will not have any chance of executing.\r
304	\r
305	@param SetTimerPeriod\r
306	Sets the period of the timer interrupt in 100 nS units.\r
307	This function is optional, and may return EFI_UNSUPPORTED.\r
308	If this function is supported, then the timer period will\r
309	be rounded up to the nearest supported timer period.\r
310	\r
311	@param GetTimerPeriod\r
312	Retrieves the period of the timer interrupt in 100 nS units.\r
313	\r
314	**/\r
315	EFI_WATCHDOG_TIMER_ARCH_PROTOCOL gWatchdogTimer = {\r
316	(EFI_WATCHDOG_TIMER_REGISTER_HANDLER) SP805RegisterHandler,\r
317	(EFI_WATCHDOG_TIMER_SET_TIMER_PERIOD) SP805SetTimerPeriod,\r
318	(EFI_WATCHDOG_TIMER_GET_TIMER_PERIOD) SP805GetTimerPeriod\r
319	};\r
320	\r
321	/**\r
322	Initialize the state information for the Watchdog Timer Architectural Protocol.\r
323	\r
324	@param ImageHandle of the loaded driver\r
325	@param SystemTable Pointer to the System Table\r
326	\r
327	@retval EFI_SUCCESS Protocol registered\r
328	@retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure\r
329	@retval EFI_DEVICE_ERROR Hardware problems\r
330	\r
331	**/\r
332	EFI_STATUS\r
333	EFIAPI\r
334	SP805Initialize (\r
335	IN EFI_HANDLE ImageHandle,\r
336	IN EFI_SYSTEM_TABLE *SystemTable\r
337	)\r
338	{\r
339	EFI_STATUS Status;\r
340	EFI_HANDLE Handle;\r
341	\r
342	// Unlock access to the SP805 registers\r
343	SP805Unlock ();\r
344	\r
345	// Stop the watchdog from triggering unexpectedly\r
346	SP805Stop ();\r
347	\r
348	// Set the watchdog to reset the board when triggered\r
349	if ((MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_RESEN) == 0) {\r
350	MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_RESEN);\r
351	}\r
352	\r
353	// Prohibit any rogue access to SP805 registers\r
354	SP805Lock();\r
355	\r
356	//\r
357	// Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.\r
358	// This will avoid conflicts with the universal watchdog\r
359	//\r
360	ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);\r
361	\r
362	// Register for an ExitBootServicesEvent\r
363	Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent);\r
364	if (EFI_ERROR(Status)) {\r
365	Status = EFI_OUT_OF_RESOURCES;\r
366	goto EXIT;\r
367	}\r
368	\r
369	// Install the Timer Architectural Protocol onto a new handle\r
370	Handle = NULL;\r
371	Status = gBS->InstallMultipleProtocolInterfaces(\r
372	&Handle,\r
373	&gEfiWatchdogTimerArchProtocolGuid, &gWatchdogTimer,\r
374	NULL\r
375	);\r
376	if (EFI_ERROR(Status)) {\r
377	Status = EFI_OUT_OF_RESOURCES;\r
378	goto EXIT;\r
379	}\r
380	\r
381	EXIT:\r
382	if(EFI_ERROR(Status)) {\r
383	// The watchdog failed to initialize\r
384	ASSERT(FALSE);\r
385	}\r
386	return Status;\r
387	}\r