On Thu, Apr 23, 2020 at 12:02:16 +0000, Pankaj Bansal (OSS) wrote:
>
>
> > -----Original Message-----
> > From: Leif Lindholm <[email protected]>
> > Sent: Thursday, April 23, 2020 5:27 PM
> > To: Pankaj Bansal (OSS) <[email protected]>
> > Cc: Meenakshi Aggarwal <[email protected]>; Michael D Kinney
> > <[email protected]>; [email protected]; Varun Sethi
> > <[email protected]>; Samer El-Haj-Mahmoud <Samer.El-Haj-
> > [email protected]>; Jon Nettleton <[email protected]>; Ard Biesheuvel
> > <[email protected]>
> > Subject: Re: [PATCH edk2-platforms v3 16/24] Silicon/NXP: Add Chassis2
> > Package
> >
> > On Thu, Apr 23, 2020 at 11:38:12 +0000, Pankaj Bansal (OSS) wrote:
> > > > > +
> > > > > + @return The value read.
> > > > > +**/
> > > > > +UINT32
> > > > > +EFIAPI
> > > > > +DcfgRead32 (
> > > > > + IN UINTN Address
> > > > > + )
> > > > > +{
> > > > > + MMIO_OPERATIONS_32 *DcfgOps;
> > > > > +
> > > > > + DcfgOps = GetMmioOperations32 (FeaturePcdGet (PcdDcfgBigEndian));
> > > > > +
> > > > > + return DcfgOps->Read32 (Address);
> > > > > +}
> > > >
> > > > The intended usage model for IoAccessLib is to retrieve the function
> > > > pointer struct once and then always refer to it. Since this is a
> > > > library, we could have a CONSTRUCTOR function (specified in the .inf)
> > >
> > > I had thought of this, but decided against it because of this reason:
> > > The order of Library constructor call for a module cannot be
> > > guaranteed.
> > > https://edk2.groups.io/g/devel/message/57254 is an good example of
> > > this.
> > > BaseDebugLibSerialPortConstructor would need to depend on
> > ChassisLibConstructor,
> > > to retrieve the UART clock frequency. If the constructor calls are not
> > guaranteed, BaseDebugLibSerialPortConstructor
> > > would fail and it would cause ASSERT due to ASSERT_RETURN_ERROR
> > (Status)
> >
> > If this is a problem (and I recall Ard pointing out some shortcomings
> > in the dependency handling in the past), we can solve this with an
> > explicit initialisation call in the SoC or platform init code.
>
> You mean put ChassisLibConstructor() call in SerialPortInitialize () ?
Or before the call to SerialPortInitialize in ChassisInit.
/
Leif
>
> >
> > /
> > Leif
> >
> > >
> > > > and do something like:
> > > >
> > > > STATIC MMIO_OPERATIONS mDcfgOps;
> > > >
> > > > /**
> > > > Read Dcfg register
> > > >
> > > > @param Address The MMIO register to read.
> > > >
> > > > @return The value read.
> > > > **/
> > > > UINT32
> > > > EFIAPI
> > > > DcfgRead32 (
> > > > IN UINTN Address
> > > > )
> > > > {
> > > > return mDcfgOps->Read32 (Address);
> > > > }
> > > >
> > > > /**
> > > > Write Dcfg register
> > > >
> > > > @param Address The MMIO register to write.
> > > > @param Value The value to write to the MMIO register.
> > > >
> > > > @return Value.
> > > >
> > > > **/
> > > > UINT32
> > > > EFIAPI
> > > > DcfgWrite32 (
> > > > IN UINTN Address,
> > > > IN UINT32 Value
> > > > )
> > > > {
> > > > return mDcfgOps->Write32 (Address, Value);
> > > > }
> > > >
> > > > ...
> > > >
> > > > /**
> > > > The constructor function initializes the IoAccessLib
> > > > function pointer structure.
> > > >
> > > > @retval RETURN_SUCCESS The constructor always returns EFI_SUCCESS.
> > > >
> > > > **/
> > > > EFI_STATUS
> > > > EFIAPI
> > > > ChassisLibConstructor (
> > > > VOID
> > > > )
> > > > {
> > > > mDcfgOps = GetMmioOperations (FeaturePcdGet (PcdDcfgBigEndian));
> > > >
> > > > return EFI_SUCCESS;
> > > > }
> > > >
> > > > /
> > > > Leif
> > > >
> > >
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