ArmPkg: Fix bug in Generic Watchdog driver

In ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c, the following
functions:

  WatchdogWriteOffsetRegister()
  WatchdogWriteCompareRegister()
  WatchdogEnable()
  WatchdogDisable()

provide write access to ARM Generic Watchdog registers and use the values
returned by MmioWrite32() and MmioWrite64() as EFI_STATUS return codes.

Because MmioWriteXY() return the value passed as its write parameter,
Generic Watchdog access functions can spuriously return error codes which
are different from EFI_SUCCESS, e.g. the following call

    Status = WatchdogWriteOffsetRegister (MAX_UINT32);
    if (EFI_ERROR (Status)) {
      return Status;
    }

will return MAX_UINT32 defined in MdePkg/Include/Base.h as

 #define MAX_UINT32  ((UINT32)0xFFFFFFFF)

This commit declares all the functions listed above as VOID
and removes the code for checking their return values.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Alexei Fedorov <alexei.fedorov@arm.com>
Reviewed-by: Evan Lloyd <evan.lloyd@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

1 files changed, 16 insertions, 21 deletions

diff --git a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
index 252ba5bf32..3180f01125 100644
--- a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
+++ b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
@@ -1,6 +1,6 @@
 /** @file

 *

-*  Copyright (c) 2013-2017, ARM Limited. All rights reserved.

+*  Copyright (c) 2013-2018, ARM Limited. All rights reserved.

 *

 *  This program and the accompanying materials

 *  are licensed and made available under the terms and conditions of the BSD

@@ -43,36 +43,36 @@ UINT64 mNumTimerTicks = 0;
 

 EFI_HARDWARE_INTERRUPT2_PROTOCOL *mInterruptProtocol;

 

-EFI_STATUS

+VOID

 WatchdogWriteOffsetRegister (

   UINT32  Value

   )

 {

-  return MmioWrite32 (GENERIC_WDOG_OFFSET_REG, Value);

+  MmioWrite32 (GENERIC_WDOG_OFFSET_REG, Value);

 }

 

-EFI_STATUS

+VOID

 WatchdogWriteCompareRegister (

   UINT64  Value

   )

 {

-  return MmioWrite64 (GENERIC_WDOG_COMPARE_VALUE_REG, Value);

+  MmioWrite64 (GENERIC_WDOG_COMPARE_VALUE_REG, Value);

 }

 

-EFI_STATUS

+VOID

 WatchdogEnable (

   VOID

   )

 {

-  return MmioWrite32 (GENERIC_WDOG_CONTROL_STATUS_REG, GENERIC_WDOG_ENABLED);

+  MmioWrite32 (GENERIC_WDOG_CONTROL_STATUS_REG, GENERIC_WDOG_ENABLED);

 }

 

-EFI_STATUS

+VOID

 WatchdogDisable (

   VOID

   )

 {

-  return MmioWrite32 (GENERIC_WDOG_CONTROL_STATUS_REG, GENERIC_WDOG_DISABLED);

+  MmioWrite32 (GENERIC_WDOG_CONTROL_STATUS_REG, GENERIC_WDOG_DISABLED);

 }

 

 /** On exiting boot services we must make sure the Watchdog Timer

@@ -163,9 +163,7 @@ WatchdogRegisterHandler (
                            then the watchdog timer is disabled.

 

   @retval EFI_SUCCESS           The watchdog timer has been programmed to fire

-                                in Time  100ns units.

-  @retval EFI_DEVICE_ERROR      A watchdog timer could not be programmed due

-                                to a device error.

+                                in TimerPeriod 100ns units.

 

 **/

 EFI_STATUS

@@ -176,12 +174,12 @@ WatchdogSetTimerPeriod (
   )

 {

   UINTN       SystemCount;

-  EFI_STATUS  Status;

 

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

   if (TimerPeriod == 0) {

     mNumTimerTicks = 0;

-    return WatchdogDisable ();

+    WatchdogDisable ();

+    return EFI_SUCCESS;

   }

 

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

@@ -195,19 +193,16 @@ WatchdogSetTimerPeriod (
        because enabling the watchdog causes an "explicit refresh", which

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

        trigger an interrupt, set the offset to max. */

-    Status = WatchdogWriteOffsetRegister (MAX_UINT32);

-    if (EFI_ERROR (Status)) {

-      return Status;

-    }

+    WatchdogWriteOffsetRegister (MAX_UINT32);

     WatchdogEnable ();

     SystemCount = ArmGenericTimerGetSystemCount ();

-    Status      = WatchdogWriteCompareRegister (SystemCount + mNumTimerTicks);

+    WatchdogWriteCompareRegister (SystemCount + mNumTimerTicks);

   } else {

-    Status = WatchdogWriteOffsetRegister ((UINT32)mNumTimerTicks);

+    WatchdogWriteOffsetRegister ((UINT32)mNumTimerTicks);

     WatchdogEnable ();

   }

 

-  return Status;

+  return EFI_SUCCESS;

 }

 

 /**