ActivateHpetSupport.c

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#include <Uefi.h>
 
#include <IndustryStandard/Pci.h>
 
#include <Protocol/PciIo.h>
 
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/IoLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/OcDeviceMiscLib.h>
 
#include "PciExtInternal.h"
 
VOID
ActivateHpetSupport (
  VOID
  )
{
  EFI_STATUS           Status;
  UINTN                HandleCount;
  EFI_HANDLE           *HandleBuffer;
  UINTN                Index;
  EFI_PCI_IO_PROTOCOL  *PciIo;
  PCI_CLASSCODE        ClassCode;
  UINT32               Rcba;
  UINT32               Hptc;
 
  Status = gBS->LocateHandleBuffer (
                  ByProtocol,
                  &gEfiPciIoProtocolGuid,
                  NULL,
                  &HandleCount,
                  &HandleBuffer
                  );
 
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_INFO, "OCDM: No PCI devices for HPET support - %r\n", Status));
    return;
  }
 
  for (Index = 0; Index < HandleCount; ++Index) {
    Status = gBS->HandleProtocol (
                    HandleBuffer[Index],
                    &gEfiPciIoProtocolGuid,
                    (VOID **)&PciIo
                    );
 
    if (EFI_ERROR (Status)) {
      continue;
    }
 
    Status = PciIo->Pci.Read (
                          PciIo,
                          EfiPciIoWidthUint8,
                          PCI_CLASSCODE_OFFSET,
                          sizeof (PCI_CLASSCODE) / sizeof (UINT8),
                          &ClassCode
                          );
    if (EFI_ERROR (Status)) {
      continue;
    }
 
    if ((ClassCode.BaseCode == PCI_CLASS_BRIDGE) && (ClassCode.SubClassCode == PCI_CLASS_BRIDGE_ISA)) {
      Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint32, PCI_BRIDGE_RCBA_OFFSET, 1, &Rcba);
      if (EFI_ERROR (Status)) {
        continue;
      }
 
      DEBUG ((
        DEBUG_INFO,
        "OCDM: Discovered RCBA device at %u/%u at 0x%X\n",
        (UINT32)(Index + 1),
        (UINT32)HandleCount,
        Rcba
        ));
 
      //
      // Disabled completely. Ignore.
      //
      if ((Rcba & PCI_BRIDGE_RCBA_ADDRESS_MASK) == 0) {
        continue;
      }
 
      //
      // Disabled access. Try to enable.
      //
      if ((Rcba & PCI_BRIDGE_RCBA_ACCESS_ENABLE) == 0) {
        Rcba |= PCI_BRIDGE_RCBA_ACCESS_ENABLE;
        PciIo->Pci.Write (PciIo, EfiPciIoWidthUint32, PCI_BRIDGE_RCBA_OFFSET, 1, &Rcba);
      }
 
      Rcba &= PCI_BRIDGE_RCBA_ADDRESS_MASK;
 
      Hptc = MmioRead32 (Rcba + RCBA_HTPC_REGISTER);
 
      DEBUG ((
        DEBUG_INFO,
        "OCDM: Discovered HPTC register with 0x%X value\n",
        Hptc
        ));
 
      if ((Hptc & RCBA_HTPC_HPET_ENABLE) == 0) {
        MmioWrite32 (Rcba + RCBA_HTPC_REGISTER, Hptc | RCBA_HTPC_HPET_ENABLE);
        Hptc = MmioRead32 (Rcba + RCBA_HTPC_REGISTER);
 
        DEBUG ((
          DEBUG_INFO,
          "OCDM: Updated HPTC register with HPET has 0x%X value\n",
          Hptc
          ));
      }
    }
  }
}