Re: [Xen-devel] [PATCH v2 08/29] ArmVirtualizationPkg: add padding to FDT allocation

["Olivier Martin" <olivier.martin@xxxxxxx>]

Same question as last time, would it not be better to have a PCD instead of
hardcoded value?
Some platforms might want to have a larger FDT padding.


> -----Original Message-----
> From: Ard Biesheuvel [mailto:ard.biesheuvel@xxxxxxxxxx]
> Sent: 26 January 2015 19:03
> To: edk2-devel@xxxxxxxxxxxxxxxxxxxxx; lersek@xxxxxxxxxx; Olivier
> Martin; roy.franz@xxxxxxxxxx; leif.lindholm@xxxxxxxxxx;
> stefano.stabellini@xxxxxxxxxxxxx; Ian.Campbell@xxxxxxxxxx;
> anthony.perard@xxxxxxxxxx; christoffer.dall@xxxxxxxxxx; xen-
> devel@xxxxxxxxxxxxx; ilias.biris@xxxxxxxxxx
> Cc: Ard Biesheuvel
> Subject: [PATCH v2 08/29] ArmVirtualizationPkg: add padding to FDT
> allocation
> 
> Our primary user QEMU/mach-virt presents us with a FDT blob padded
> to 64 KB with plenty of room to set additional properties. However,
> in the general case, we should only add properties after making sure
> there is enough room available.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
> 
> ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPeiL
> ib.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git
> a/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
> iLib.c
> b/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
> iLib.c
> index c500d5964b25..42a87309aebe 100644
> ---
> a/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
> iLib.c
> +++
> b/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
> iLib.c
> @@ -24,6 +24,15 @@
>  #include <Guid/EarlyPL011BaseAddress.h>
>  #include <Guid/FdtHob.h>
> 
> +//
> +// We may want to apply some changes to the device tree before passing
> it
> +// to the OS: for instance, if we find a PL031 RTC node and attach our
> +// runtime driver to it, we should disable it in the device tree by
> setting
> +// its status property to "disabled". Add some padding to make sure
> this is
> +// possible.
> +//
> +#define FDT_PADDING   256
> +
>  EFI_STATUS
>  EFIAPI
>  PlatformPeim (
> @@ -33,6 +42,7 @@ PlatformPeim (
>    VOID               *Base;
>    VOID               *NewBase;
>    UINTN              FdtSize;
> +  UINTN              FdtPages;
>    UINT64             *FdtHobData;
>    UINT64             *UartHobData;
>    INT32              Node, Prev;
> @@ -47,10 +57,11 @@ PlatformPeim (
>    ASSERT (Base != NULL);
>    ASSERT (fdt_check_header (Base) == 0);
> 
> -  FdtSize = fdt_totalsize (Base);
> -  NewBase = AllocatePages (EFI_SIZE_TO_PAGES (FdtSize));
> +  FdtSize = fdt_totalsize (Base) + FDT_PADDING;
> +  FdtPages = EFI_SIZE_TO_PAGES (FdtSize);
> +  NewBase = AllocatePages (FdtPages);
>    ASSERT (NewBase != NULL);
> -  CopyMem (NewBase, Base, FdtSize);
> +  fdt_open_into (Base, NewBase, EFI_PAGES_TO_SIZE (FdtPages));
> 
>    FdtHobData = BuildGuidHob (&gFdtHobGuid, sizeof *FdtHobData);
>    ASSERT (FdtHobData != NULL);
> --
> 1.8.3.2
> 





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