ArmPkg: Introduce global mTimerPeriod and remove calculation

The calculation of the timer period was broken. Introduce a global
mTimerPeriod so the calculation can be removed. Since mTimerFrequencyHz
is only used in one place, remove the global and make it a local
variable. Do the same with mNumTimerTicks.

Signed-off-by: Rebecca Cran <rebecca@os.amperecomputing.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

1 files changed, 14 insertions, 18 deletions

diff --git a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
index c96dc31dc6..fdcda2be1b 100644
--- a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
+++ b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
@@ -28,13 +28,10 @@
    in a second */

 #define TIME_UNITS_PER_SECOND  10000000

 

-// Tick frequency of the generic timer basis of the generic watchdog.

-STATIC UINTN  mTimerFrequencyHz = 0;

-

 /* In cases where the compare register was set manually, information about

    how long the watchdog was asked to wait cannot be retrieved from hardware.

    It is therefore stored here. 0 means the timer is not running. */

-STATIC UINT64  mNumTimerTicks = 0;

+STATIC UINT64  mTimerPeriod = 0;

 

 #define MAX_UINT48  0xFFFFFFFFFFFFULL

 

@@ -121,7 +118,7 @@ WatchdogExitBootServicesEvent (
   )

 {

   WatchdogDisable ();

-  mNumTimerTicks = 0;

+  mTimerPeriod = 0;

 }

 

 /* This function is called when the watchdog's first signal (WS0) goes high.

@@ -136,7 +133,6 @@ WatchdogInterruptHandler (
   )

 {

   STATIC CONST CHAR16  ResetString[] = L"The generic watchdog timer ran out.";

-  UINT64               TimerPeriod;

 

   WatchdogDisable ();

 

@@ -149,8 +145,7 @@ WatchdogInterruptHandler (
   // the timer period plus 1.

   //

   if (mWatchdogNotify != NULL) {

-    TimerPeriod = ((TIME_UNITS_PER_SECOND / mTimerFrequencyHz) * mNumTimerTicks);

-    mWatchdogNotify (TimerPeriod + 1);

+    mWatchdogNotify (mTimerPeriod + 1);

   }

 

   gRT->ResetSystem (

@@ -232,22 +227,27 @@ WatchdogSetTimerPeriod (
 {

   UINTN   SystemCount;

   UINT64  MaxWatchdogOffsetValue;

+  UINT64  TimerFrequencyHz;

+  UINT64  NumTimerTicks;

 

   // if TimerPeriod is 0, this is a request to stop the watchdog.

   if (TimerPeriod == 0) {

-    mNumTimerTicks = 0;

+    mTimerPeriod = 0;

     WatchdogDisable ();

     return EFI_SUCCESS;

   }

 

   // Work out how many timer ticks will equate to TimerPeriod

-  mNumTimerTicks = (mTimerFrequencyHz * TimerPeriod) / TIME_UNITS_PER_SECOND;

+  TimerFrequencyHz = ArmGenericTimerGetTimerFreq ();

+  ASSERT (TimerFrequencyHz != 0);

+  mTimerPeriod  = TimerPeriod;

+  NumTimerTicks = (TimerFrequencyHz * TimerPeriod) / TIME_UNITS_PER_SECOND;

 

   /* If the number of required ticks is greater than the max the watchdog's

      offset register (WOR) can hold, we need to manually compute and set

      the compare register (WCV) */

   MaxWatchdogOffsetValue = GetMaxWatchdogOffsetRegisterValue ();

-  if (mNumTimerTicks > MaxWatchdogOffsetValue) {

+  if (NumTimerTicks > MaxWatchdogOffsetValue) {

     /* We need to enable the watchdog *before* writing to the compare register,

        because enabling the watchdog causes an "explicit refresh", which

        clobbers the compare register (WCV). In order to make sure this doesn't

@@ -255,9 +255,9 @@ WatchdogSetTimerPeriod (
     WatchdogWriteOffsetRegister (MaxWatchdogOffsetValue);

     WatchdogEnable ();

     SystemCount = ArmGenericTimerGetSystemCount ();

-    WatchdogWriteCompareRegister (SystemCount + mNumTimerTicks);

+    WatchdogWriteCompareRegister (SystemCount + NumTimerTicks);

   } else {

-    WatchdogWriteOffsetRegister (mNumTimerTicks);

+    WatchdogWriteOffsetRegister (NumTimerTicks);

     WatchdogEnable ();

   }

 

@@ -292,7 +292,7 @@ WatchdogGetTimerPeriod (
     return EFI_INVALID_PARAMETER;

   }

 

-  *TimerPeriod = ((TIME_UNITS_PER_SECOND / mTimerFrequencyHz) * mNumTimerTicks);

+  *TimerPeriod = mTimerPeriod;

 

   return EFI_SUCCESS;

 }

@@ -359,9 +359,6 @@ GenericWatchdogEntry (
      This will avoid conflicts with the universal watchdog */

   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);

 

-  mTimerFrequencyHz = ArmGenericTimerGetTimerFreq ();

-  ASSERT (mTimerFrequencyHz != 0);

-

   // Install interrupt handler

   Status = mInterruptProtocol->RegisterInterruptSource (

                                  mInterruptProtocol,

@@ -403,7 +400,6 @@ GenericWatchdogEntry (
                   );

   ASSERT_EFI_ERROR (Status);

 

-  mNumTimerTicks = 0;

   WatchdogDisable ();

 

   return EFI_SUCCESS;