On 2 August 2018 at 22:50, Marcin Wojtas <[email protected]> wrote:
> According to the SBSA specification the Watchdog Compare
> Register is split into two separate 32bit registers.
> EDK2 code uses a single 64bit transaction to update
> them, which can be problematic, depending on the SoC
> implementation and could result in an unpredicted behavior.
>
> Fix this by modifying WatchdogWriteCompareRegister routine to
> use two consecutive 32bit writes to the Watchdog Compare Register
> Low and High, using new dedicated macros.
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Marcin Wojtas <[email protected]>
> Reviewed-by: Leif Lindholm <[email protected]>
Pushed as dd4cae4d82c7
Thanks
> ---
> Changelog v1 -> v2:
> - use separate macros for WCV register low and high
> - improve commit message
> - add Leif's RB
>
> ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdog.h | 3 ++-
> ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c | 3 ++-
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdog.h
> b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdog.h
> index 9e2aebc..4f42c56 100644
> --- a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdog.h
> +++ b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdog.h
> @@ -20,7 +20,8 @@
> // Control Frame:
> #define GENERIC_WDOG_CONTROL_STATUS_REG ((UINTN)FixedPcdGet64
> (PcdGenericWatchdogControlBase) + 0x000)
> #define GENERIC_WDOG_OFFSET_REG ((UINTN)FixedPcdGet64
> (PcdGenericWatchdogControlBase) + 0x008)
> -#define GENERIC_WDOG_COMPARE_VALUE_REG ((UINTN)FixedPcdGet64
> (PcdGenericWatchdogControlBase) + 0x010)
> +#define GENERIC_WDOG_COMPARE_VALUE_REG_LOW ((UINTN)FixedPcdGet64
> (PcdGenericWatchdogControlBase) + 0x010)
> +#define GENERIC_WDOG_COMPARE_VALUE_REG_HIGH ((UINTN)FixedPcdGet64
> (PcdGenericWatchdogControlBase) + 0x014)
>
> // Values of bit 0 of the Control/Status Register
> #define GENERIC_WDOG_ENABLED 1
> diff --git a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
> b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
> index 3180f01..8ccf153 100644
> --- a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
> +++ b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
> @@ -56,7 +56,8 @@ WatchdogWriteCompareRegister (
> UINT64 Value
> )
> {
> - MmioWrite64 (GENERIC_WDOG_COMPARE_VALUE_REG, Value);
> + MmioWrite32 (GENERIC_WDOG_COMPARE_VALUE_REG_LOW, Value & MAX_UINT32);
> + MmioWrite32 (GENERIC_WDOG_COMPARE_VALUE_REG_HIGH, (Value >> 32) &
> MAX_UINT32);
> }
>
> VOID
> --
> 2.7.4
>
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