> -----Original Message-----
> From: Leif Lindholm <[email protected]>
> Sent: Thursday, April 23, 2020 5:36 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 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.
But SerialPortInitialize would be called from each module.
Each module that has SerialPort and ChassiLib linked to it would have a
local copy of mDcfgOps, which needs to be initialized.
>
> /
> 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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