Re: [PATCH 3/3] MdeModulePkg/PciHostBridge: Add RESOURCE_VALID() to simplify code

[Laszlo Ersek <lersek@redhat.com>]

On 09/21/18 09:25, Ruiyu Ni wrote:
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Star Zeng <star.zeng@intel.com>
> ---
>  .../Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c     | 26 ++++++++++------------
>  1 file changed, 12 insertions(+), 14 deletions(-)
> 
> diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> index f6234b5d11..916709e276 100644
> --- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> +++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> @@ -21,6 +21,8 @@ extern EDKII_IOMMU_PROTOCOL        *mIoMmuProtocol;
>  
>  #define NO_MAPPING  (VOID *) (UINTN) -1
>  
> +#define RESOURCE_VALID(R) ((R).Base <= (R).Limit)
> +
>  //
>  // Lookup table for increment values based on transfer widths
>  //
> @@ -122,25 +124,25 @@ CreateRootBridge (
>    //
>    // Make sure Mem and MemAbove4G apertures are valid
>    //
> -  if (Bridge->Mem.Base <= Bridge->Mem.Limit) {
> +  if (RESOURCE_VALID (Bridge->Mem)) {
>      ASSERT (Bridge->Mem.Limit < SIZE_4GB);
>      if (Bridge->Mem.Limit >= SIZE_4GB) {
>        return NULL;
>      }
>    }
> -  if (Bridge->MemAbove4G.Base <= Bridge->MemAbove4G.Limit) {
> +  if (RESOURCE_VALID (Bridge->MemAbove4G)) {
>      ASSERT (Bridge->MemAbove4G.Base >= SIZE_4GB);
>      if (Bridge->MemAbove4G.Base < SIZE_4GB) {
>        return NULL;
>      }
>    }
> -  if (Bridge->PMem.Base <= Bridge->PMem.Limit) {
> +  if (RESOURCE_VALID (Bridge->PMem)) {
>      ASSERT (Bridge->PMem.Limit < SIZE_4GB);
>      if (Bridge->PMem.Limit >= SIZE_4GB) {
>        return NULL;
>      }
>    }
> -  if (Bridge->PMemAbove4G.Base <= Bridge->PMemAbove4G.Limit) {
> +  if (RESOURCE_VALID (Bridge->PMemAbove4G)) {
>      ASSERT (Bridge->PMemAbove4G.Base >= SIZE_4GB);
>      if (Bridge->PMemAbove4G.Base < SIZE_4GB) {
>        return NULL;
> @@ -157,11 +159,9 @@ CreateRootBridge (
>        // support separate windows for Non-prefetchable and Prefetchable
>        // memory.
>        //
> -      ASSERT (Bridge->PMem.Base > Bridge->PMem.Limit);
> -      ASSERT (Bridge->PMemAbove4G.Base > Bridge->PMemAbove4G.Limit);
> -      if ((Bridge->PMem.Base <= Bridge->PMem.Limit) ||
> -          (Bridge->PMemAbove4G.Base <= Bridge->PMemAbove4G.Limit)
> -          ) {
> +      ASSERT (!RESOURCE_VALID (Bridge->PMem));
> +      ASSERT (!RESOURCE_VALID (Bridge->PMemAbove4G));
> +      if (RESOURCE_VALID (Bridge->PMem) || RESOURCE_VALID (Bridge->PMemAbove4G)) {
>          return NULL;
>        }
>      }
> @@ -171,11 +171,9 @@ CreateRootBridge (
>        // If this bit is not set, then the PCI Root Bridge does not support
>        // 64 bit memory windows.
>        //
> -      ASSERT (Bridge->MemAbove4G.Base > Bridge->MemAbove4G.Limit);
> -      ASSERT (Bridge->PMemAbove4G.Base > Bridge->PMemAbove4G.Limit);
> -      if ((Bridge->MemAbove4G.Base <= Bridge->MemAbove4G.Limit) ||
> -          (Bridge->PMemAbove4G.Base <= Bridge->PMemAbove4G.Limit)
> -          ) {
> +      ASSERT (!RESOURCE_VALID (Bridge->MemAbove4G));
> +      ASSERT (!RESOURCE_VALID (Bridge->PMemAbove4G));
> +      if (RESOURCE_VALID (Bridge->MemAbove4G) || RESOURCE_VALID (Bridge->PMemAbove4G)) {
>          return NULL;
>        }
>      }
> 

Two superficial comments:

- edk2 prefers long parameter names, so I suggest replacing "R" in the
macro definition with "Resource"

- taking the parameter as a pointer is frequently considered more flexible.

#define RESOURCE_VALID(Resource) ((Resource)->Base <= (Resource)->Limit)
...
if (RESOURCE_VALID (&Bridge->Mem)) {
...

Up to you -- if you like these, feel free to update the patch before
pushing it (from my side anyway; you do need MdeModulePkg maintainer
review as well).

With or without changes:

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks
Laszlo