/** @file
  FDT client library for consumers of PCI related dynamic PCDs

  Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>

  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include <Uefi.h>

#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiBootServicesTableLib.h>

#include <Protocol/FdtClient.h>

//
// We expect the "ranges" property of "pci-host-ecam-generic" to consist of
// records like this.
//
#pragma pack (1)
typedef struct {
  UINT32 Type;
  UINT64 ChildBase;
  UINT64 CpuBase;
  UINT64 Size;
} DTB_PCI_HOST_RANGE_RECORD;
#pragma pack ()

#define DTB_PCI_HOST_RANGE_RELOCATABLE  BIT31
#define DTB_PCI_HOST_RANGE_PREFETCHABLE BIT30
#define DTB_PCI_HOST_RANGE_ALIASED      BIT29
#define DTB_PCI_HOST_RANGE_MMIO32       BIT25
#define DTB_PCI_HOST_RANGE_MMIO64       (BIT25 | BIT24)
#define DTB_PCI_HOST_RANGE_IO           BIT24
#define DTB_PCI_HOST_RANGE_TYPEMASK     (BIT31 | BIT30 | BIT29 | BIT25 | BIT24)

STATIC
RETURN_STATUS
GetPciIoTranslation (
  IN  FDT_CLIENT_PROTOCOL *FdtClient,
  IN  INT32               Node,
  OUT UINT64              *IoTranslation
  )
{
  UINT32        RecordIdx;
  CONST VOID    *Prop;
  UINT32        Len;
  EFI_STATUS    Status;
  UINT64        IoBase;

  //
  // Iterate over "ranges".
  //
  Status = FdtClient->GetNodeProperty (FdtClient, Node, "ranges", &Prop, &Len);
  if (EFI_ERROR (Status) || Len == 0 ||
      Len % sizeof (DTB_PCI_HOST_RANGE_RECORD) != 0) {
    DEBUG ((EFI_D_ERROR, "%a: 'ranges' not found or invalid\n", __FUNCTION__));
    return RETURN_PROTOCOL_ERROR;
  }

  for (RecordIdx = 0; RecordIdx < Len / sizeof (DTB_PCI_HOST_RANGE_RECORD);
       ++RecordIdx) {
    CONST DTB_PCI_HOST_RANGE_RECORD *Record;
    UINT32                          Type;

    Record = (CONST DTB_PCI_HOST_RANGE_RECORD *)Prop + RecordIdx;
    Type = SwapBytes32 (Record->Type) & DTB_PCI_HOST_RANGE_TYPEMASK;
    if (Type == DTB_PCI_HOST_RANGE_IO) {
      IoBase = SwapBytes64 (Record->ChildBase);
      *IoTranslation = SwapBytes64 (Record->CpuBase) - IoBase;

      return RETURN_SUCCESS;
    }
  }
  return RETURN_NOT_FOUND;
}

RETURN_STATUS
EFIAPI
FdtPciPcdProducerLibConstructor (
  VOID
  )
{
  UINT64              PciExpressBaseAddress;
  FDT_CLIENT_PROTOCOL *FdtClient;
  CONST UINT64        *Reg;
  UINT32              RegSize;
  EFI_STATUS          Status;
  INT32               Node;
  RETURN_STATUS       RetStatus;
  UINT64              IoTranslation;
  RETURN_STATUS       PcdStatus;

  PciExpressBaseAddress = PcdGet64 (PcdPciExpressBaseAddress);
  if (PciExpressBaseAddress != MAX_UINT64) {
    //
    // Assume that the fact that PciExpressBaseAddress has been changed from
    // its default value of MAX_UINT64 implies that this code has been
    // executed already, in the context of another module. That means we can
    // assume that PcdPciIoTranslation has been discovered from the DT node
    // as well.
    //
    return EFI_SUCCESS;
  }

  Status = gBS->LocateProtocol (&gFdtClientProtocolGuid, NULL,
                  (VOID **)&FdtClient);
  ASSERT_EFI_ERROR (Status);

  PciExpressBaseAddress = 0;
  Status = FdtClient->FindCompatibleNode (FdtClient, "pci-host-ecam-generic",
                        &Node);

  if (!EFI_ERROR (Status)) {
    Status = FdtClient->GetNodeProperty (FdtClient, Node, "reg",
                          (CONST VOID **)&Reg, &RegSize);

    if (!EFI_ERROR (Status) && RegSize == 2 * sizeof (UINT64)) {
      PciExpressBaseAddress = SwapBytes64 (*Reg);

      PcdStatus = PcdSetBoolS (PcdPciDisableBusEnumeration, FALSE);
      ASSERT_RETURN_ERROR (PcdStatus);

      IoTranslation = 0;
      RetStatus = GetPciIoTranslation (FdtClient, Node, &IoTranslation);
      if (!RETURN_ERROR (RetStatus)) {
          PcdStatus = PcdSet64S (PcdPciIoTranslation, IoTranslation);
          ASSERT_RETURN_ERROR (PcdStatus);
      } else {
        //
        // Support for I/O BARs is not mandatory, and so it does not make sense
        // to abort in the general case. So leave it up to the actual driver to
        // complain about this if it wants to, and just issue a warning here.
        //
        DEBUG ((EFI_D_WARN,
          "%a: 'pci-host-ecam-generic' device encountered with no I/O range\n",
          __FUNCTION__));
      }
    }
  }

  PcdStatus = PcdSet64S (PcdPciExpressBaseAddress, PciExpressBaseAddress);
  ASSERT_RETURN_ERROR (PcdStatus);

  return RETURN_SUCCESS;
}