/** @file

  This driver produces Virtio Device Protocol instances for Virtio PCI devices.

  Copyright (C) 2012, Red Hat, Inc.
  Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
  Copyright (C) 2013, ARM Ltd.

  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 <IndustryStandard/Pci.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>

#include "VirtioPciDevice.h"

STATIC VIRTIO_DEVICE_PROTOCOL mDeviceProtocolTemplate = {
  0,                                    // Revision
  0,                                    // SubSystemDeviceId
  VirtioPciGetDeviceFeatures,           // GetDeviceFeatures
  VirtioPciSetGuestFeatures,            // SetGuestFeatures
  VirtioPciGetQueueAddress,             // GetQueueAddress
  VirtioPciSetQueueAddress,             // SetQueueAddress
  VirtioPciSetQueueSel,                 // SetQueueSel
  VirtioPciSetQueueNotify,              // SetQueueNotify
  VirtioPciSetQueueAlignment,           // SetQueueAlignment
  VirtioPciSetPageSize,                 // SetPageSize
  VirtioPciGetQueueSize,                // GetQueueNumMax
  VirtioPciSetQueueSize,                // SetQueueNum
  VirtioPciGetDeviceStatus,             // GetDeviceStatus
  VirtioPciSetDeviceStatus,             // SetDeviceStatus
  VirtioPciDeviceWrite,                 // WriteDevice
  VirtioPciDeviceRead                   // ReadDevice
};

/**

  Read a word from Region 0 of the device specified by PciIo.

  Region 0 must be an iomem region. This is an internal function for the PCI
  implementation of the protocol.

  @param[in] Dev          Virtio PCI device.

  @param[in] FieldOffset  Source offset.

  @param[in] FieldSize    Source field size, must be in { 1, 2, 4, 8 }.

  @param[in] BufferSize   Number of bytes available in the target buffer. Must
                          equal FieldSize.

  @param[out] Buffer      Target buffer.


  @return  Status code returned by PciIo->Io.Read().

**/
EFI_STATUS
EFIAPI
VirtioPciIoRead (
  IN  VIRTIO_PCI_DEVICE         *Dev,
  IN  UINTN                     FieldOffset,
  IN  UINTN                     FieldSize,
  IN  UINTN                     BufferSize,
  OUT VOID                      *Buffer
  )
{
  UINTN                     Count;
  EFI_PCI_IO_PROTOCOL_WIDTH Width;
  EFI_PCI_IO_PROTOCOL       *PciIo;

  ASSERT (FieldSize == BufferSize);

  PciIo = Dev->PciIo;
  Count = 1;

  switch (FieldSize) {
    case 1:
      Width = EfiPciIoWidthUint8;
      break;

    case 2:
      Width = EfiPciIoWidthUint16;
      break;

    case 8:
      //
      // The 64bit PCI I/O is broken down into two 32bit reads to prevent
      // any alignment or width issues.
      // The UEFI spec says under EFI_PCI_IO_PROTOCOL.Io.Write():
      //
      // The I/O operations are carried out exactly as requested. The caller
      // is responsible for any alignment and I/O width issues which the
      // bus, device, platform, or type of I/O might require. For example on
      // some platforms, width requests of EfiPciIoWidthUint64 do not work.
      //
      Count = 2;

      //
      // fall through
      //
    case 4:
      Width = EfiPciIoWidthUint32;
      break;

    default:
      ASSERT (FALSE);
      return EFI_INVALID_PARAMETER;
  }

  return PciIo->Io.Read (
                     PciIo,
                     Width,
                     PCI_BAR_IDX0,
                     FieldOffset,
                     Count,
                     Buffer
                     );
}

/**

  Write a word into Region 0 of the device specified by PciIo.

  Region 0 must be an iomem region. This is an internal function for the PCI
  implementation of the protocol.

  @param[in] Dev          Virtio PCI device.

  @param[in] FieldOffset  Destination offset.

  @param[in] FieldSize    Destination field size, must be in { 1, 2, 4, 8 }.

  @param[in] Value        Little endian value to write, converted to UINT64.
                          The least significant FieldSize bytes will be used.


  @return  Status code returned by PciIo->Io.Write().

**/
EFI_STATUS
EFIAPI
VirtioPciIoWrite (
  IN  VIRTIO_PCI_DEVICE         *Dev,
  IN UINTN                      FieldOffset,
  IN UINTN                      FieldSize,
  IN UINT64                     Value
  )
{
  UINTN                     Count;
  EFI_PCI_IO_PROTOCOL_WIDTH Width;
  EFI_PCI_IO_PROTOCOL       *PciIo;

  PciIo = Dev->PciIo;
  Count = 1;

  switch (FieldSize) {
    case 1:
      Width = EfiPciIoWidthUint8;
      break;

    case 2:
      Width = EfiPciIoWidthUint16;
      break;

    case 8:
      //
      // The 64bit PCI I/O is broken down into two 32bit writes to prevent
      // any alignment or width issues.
      // The UEFI spec says under EFI_PCI_IO_PROTOCOL.Io.Write():
      //
      // The I/O operations are carried out exactly as requested. The caller
      // is responsible for any alignment and I/O width issues which the
      // bus, device, platform, or type of I/O might require. For example on
      // some platforms, width requests of EfiPciIoWidthUint64 do not work
      //
      Count = Count * 2;

      //
      // fall through
      //
    case 4:
      Width = EfiPciIoWidthUint32;
      break;

    default:
      ASSERT (FALSE);
      return EFI_INVALID_PARAMETER;
  }

  return PciIo->Io.Write (
                     PciIo,
                     Width,
                     PCI_BAR_IDX0,
                     FieldOffset,
                     Count,
                     &Value
                     );
}

/**

  Device probe function for this driver.

  The DXE core calls this function for any given device in order to see if the
  driver can drive the device.

  @param[in]  This                The EFI_DRIVER_BINDING_PROTOCOL object
                                  incorporating this driver (independently of
                                  any device).

  @param[in] DeviceHandle         The device to probe.

  @param[in] RemainingDevicePath  Relevant only for bus drivers, ignored.


  @retval EFI_SUCCESS      The driver supports the device being probed.

  @retval EFI_UNSUPPORTED  Based on virtio-pci discovery, we do not support
                           the device.

  @return                  Error codes from the OpenProtocol() boot service or
                           the PciIo protocol.

**/
STATIC
EFI_STATUS
EFIAPI
VirtioPciDeviceBindingSupported (
  IN EFI_DRIVER_BINDING_PROTOCOL *This,
  IN EFI_HANDLE                  DeviceHandle,
  IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
  )
{
  EFI_STATUS          Status;
  EFI_PCI_IO_PROTOCOL *PciIo;
  PCI_TYPE00          Pci;

  //
  // Attempt to open the device with the PciIo set of interfaces. On success,
  // the protocol is "instantiated" for the PCI device. Covers duplicate open
  // attempts (EFI_ALREADY_STARTED).
  //
  Status = gBS->OpenProtocol (
                  DeviceHandle,               // candidate device
                  &gEfiPciIoProtocolGuid,     // for generic PCI access
                  (VOID **)&PciIo,            // handle to instantiate
                  This->DriverBindingHandle,  // requestor driver identity
                  DeviceHandle,               // ControllerHandle, according to
                                              // the UEFI Driver Model
                  EFI_OPEN_PROTOCOL_BY_DRIVER // get exclusive PciIo access to
                                              // the device; to be released
                  );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  //
  // Read entire PCI configuration header for more extensive check ahead.
  //
  Status = PciIo->Pci.Read (
                        PciIo,                        // (protocol, device)
                                                      // handle
                        EfiPciIoWidthUint32,          // access width & copy
                                                      // mode
                        0,                            // Offset
                        sizeof Pci / sizeof (UINT32), // Count
                        &Pci                          // target buffer
                        );

  if (Status == EFI_SUCCESS) {
    //
    // virtio-0.9.5, 2.1 PCI Discovery
    //
    if ((Pci.Hdr.VendorId == VIRTIO_VENDOR_ID) &&
        (Pci.Hdr.DeviceId >= 0x1000) &&
        (Pci.Hdr.DeviceId <= 0x103F) &&
        (Pci.Hdr.RevisionID == 0x00)) {
      Status = EFI_SUCCESS;
    } else {
      Status = EFI_UNSUPPORTED;
    }
  }

  //
  // We needed PCI IO access only transitorily, to see whether we support the
  // device or not.
  //
  gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
         This->DriverBindingHandle, DeviceHandle);

  return Status;
}

/**

  Initialize the VirtIo PCI Device

  @param[in, out] Dev      The driver instance to configure. The caller is
                           responsible for Device->PciIo's validity (ie. working IO
                           access to the underlying virtio-pci device).

  @retval EFI_SUCCESS      Setup complete.

  @retval EFI_UNSUPPORTED  The underlying IO device doesn't support the
                           provided address offset and read size.

  @return                  Error codes from PciIo->Pci.Read().

**/
STATIC
EFI_STATUS
EFIAPI
VirtioPciInit (
  IN OUT VIRTIO_PCI_DEVICE *Device
  )
{
  EFI_STATUS            Status;
  EFI_PCI_IO_PROTOCOL   *PciIo;
  PCI_TYPE00            Pci;

  ASSERT (Device != NULL);
  PciIo = Device->PciIo;
  ASSERT (PciIo != NULL);
  ASSERT (PciIo->Pci.Read != NULL);

  Status = PciIo->Pci.Read (
                        PciIo,                        // (protocol, device)
                                                      // handle
                        EfiPciIoWidthUint32,          // access width & copy
                                                      // mode
                        0,                            // Offset
                        sizeof (Pci) / sizeof (UINT32), // Count
                        &Pci                          // target buffer
                        );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  //
  // Copy protocol template
  //
  CopyMem (&Device->VirtioDevice, &mDeviceProtocolTemplate,
      sizeof (VIRTIO_DEVICE_PROTOCOL));

  //
  // Initialize the protocol interface attributes
  //
  Device->VirtioDevice.Revision = VIRTIO_SPEC_REVISION (0, 9, 5);
  Device->VirtioDevice.SubSystemDeviceId = Pci.Device.SubsystemID;

  //
  // Note: We don't support the MSI-X capability.  If we did,
  //       the offset would become 24 after enabling MSI-X.
  //
  Device->DeviceSpecificConfigurationOffset =
      VIRTIO_DEVICE_SPECIFIC_CONFIGURATION_OFFSET_PCI;

  return EFI_SUCCESS;
}

/**

  Uninitialize the internals of a virtio-pci device that has been successfully
  set up with VirtioPciInit().

  @param[in, out]  Dev  The device to clean up.

**/

STATIC
VOID
EFIAPI
VirtioPciUninit (
  IN OUT VIRTIO_PCI_DEVICE *Device
  )
{
  // Note: This function mirrors VirtioPciInit() that does not allocate any
  //       resources - there's nothing to free here.
}

/**

  After we've pronounced support for a specific device in
  DriverBindingSupported(), we start managing said device (passed in by the
  Driver Exeuction Environment) with the following service.

  See DriverBindingSupported() for specification references.

  @param[in]  This                The EFI_DRIVER_BINDING_PROTOCOL object
                                  incorporating this driver (independently of
                                  any device).

  @param[in] DeviceHandle         The supported device to drive.

  @param[in] RemainingDevicePath  Relevant only for bus drivers, ignored.


  @retval EFI_SUCCESS           Driver instance has been created and
                                initialized  for the virtio-pci device, it
                                is now accessible via VIRTIO_DEVICE_PROTOCOL.

  @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.

  @return                       Error codes from the OpenProtocol() boot
                                service, the PciIo protocol, VirtioPciInit(),
                                or the InstallProtocolInterface() boot service.

**/
STATIC
EFI_STATUS
EFIAPI
VirtioPciDeviceBindingStart (
  IN EFI_DRIVER_BINDING_PROTOCOL *This,
  IN EFI_HANDLE                  DeviceHandle,
  IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
  )
{
  VIRTIO_PCI_DEVICE   *Device;
  EFI_STATUS           Status;

  Device = (VIRTIO_PCI_DEVICE *) AllocateZeroPool (sizeof *Device);
  if (Device == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Status = gBS->OpenProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
                  (VOID **)&Device->PciIo, This->DriverBindingHandle,
                  DeviceHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);
  if (EFI_ERROR (Status)) {
    goto FreeVirtioPci;
  }

  //
  // We must retain and ultimately restore the original PCI attributes of the
  // device. See Driver Writer's Guide for UEFI 2.3.1 v1.01, 18.3 PCI drivers /
  // 18.3.2 Start() and Stop().
  //
  // The third parameter ("Attributes", input) is ignored by the Get operation.
  // The fourth parameter ("Result", output) is ignored by the Enable and Set
  // operations.
  //
  // For virtio-pci we only need IO space access.
  //
  Status = Device->PciIo->Attributes (Device->PciIo,
      EfiPciIoAttributeOperationGet, 0, &Device->OriginalPciAttributes);
  if (EFI_ERROR (Status)) {
    goto ClosePciIo;
  }

  Status = Device->PciIo->Attributes (Device->PciIo,
                         EfiPciIoAttributeOperationEnable,
                         EFI_PCI_IO_ATTRIBUTE_IO, NULL);
  if (EFI_ERROR (Status)) {
    goto ClosePciIo;
  }

  //
  // PCI IO access granted, configure protocol instance
  //

  Status = VirtioPciInit (Device);
  if (EFI_ERROR (Status)) {
    goto RestorePciAttributes;
  }

  //
  // Setup complete, attempt to export the driver instance's VirtioDevice
  // interface.
  //
  Device->Signature = VIRTIO_PCI_DEVICE_SIGNATURE;
  Status = gBS->InstallProtocolInterface (&DeviceHandle,
                  &gVirtioDeviceProtocolGuid, EFI_NATIVE_INTERFACE,
                  &Device->VirtioDevice);
  if (EFI_ERROR (Status)) {
    goto UninitDev;
  }

  return EFI_SUCCESS;

UninitDev:
  VirtioPciUninit (Device);

RestorePciAttributes:
  Device->PciIo->Attributes (Device->PciIo, EfiPciIoAttributeOperationSet,
                Device->OriginalPciAttributes, NULL);

ClosePciIo:
  gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
         This->DriverBindingHandle, DeviceHandle);

FreeVirtioPci:
  FreePool (Device);

  return Status;
}

/**

  Stop driving the Virtio PCI device

  @param[in] This               The EFI_DRIVER_BINDING_PROTOCOL object
                                incorporating this driver (independently of any
                                device).

  @param[in] DeviceHandle       Stop driving this device.

  @param[in] NumberOfChildren   Since this function belongs to a device driver
                                only (as opposed to a bus driver), the caller
                                environment sets NumberOfChildren to zero, and
                                we ignore it.

  @param[in] ChildHandleBuffer  Ignored (corresponding to NumberOfChildren).

  @retval EFI_SUCCESS           Driver instance has been stopped and the PCI
                                configuration attributes have been restored.

  @return                       Error codes from the OpenProtocol() or
                                CloseProtocol(), UninstallProtocolInterface()
                                boot services.

**/
STATIC
EFI_STATUS
EFIAPI
VirtioPciDeviceBindingStop (
  IN EFI_DRIVER_BINDING_PROTOCOL *This,
  IN EFI_HANDLE                  DeviceHandle,
  IN UINTN                       NumberOfChildren,
  IN EFI_HANDLE                  *ChildHandleBuffer
  )
{
  EFI_STATUS               Status;
  VIRTIO_DEVICE_PROTOCOL  *VirtioDevice;
  VIRTIO_PCI_DEVICE       *Device;

  Status = gBS->OpenProtocol (
                  DeviceHandle,                  // candidate device
                  &gVirtioDeviceProtocolGuid,    // retrieve the VirtIo iface
                  (VOID **)&VirtioDevice,        // target pointer
                  This->DriverBindingHandle,     // requestor driver identity
                  DeviceHandle,                  // requesting lookup for dev.
                  EFI_OPEN_PROTOCOL_GET_PROTOCOL // lookup only, no ref. added
                  );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Device = VIRTIO_PCI_DEVICE_FROM_VIRTIO_DEVICE (VirtioDevice);

  //
  // Handle Stop() requests for in-use driver instances gracefully.
  //
  Status = gBS->UninstallProtocolInterface (DeviceHandle,
                  &gVirtioDeviceProtocolGuid, &Device->VirtioDevice);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  VirtioPciUninit (Device);

  Device->PciIo->Attributes (Device->PciIo, EfiPciIoAttributeOperationSet,
                Device->OriginalPciAttributes, NULL);

  Status = gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
         This->DriverBindingHandle, DeviceHandle);

  FreePool (Device);

  return Status;
}


//
// The static object that groups the Supported() (ie. probe), Start() and
// Stop() functions of the driver together. Refer to UEFI Spec 2.3.1 + Errata
// C, 10.1 EFI Driver Binding Protocol.
//
STATIC EFI_DRIVER_BINDING_PROTOCOL gDriverBinding = {
  &VirtioPciDeviceBindingSupported,
  &VirtioPciDeviceBindingStart,
  &VirtioPciDeviceBindingStop,
  0x10, // Version, must be in [0x10 .. 0xFFFFFFEF] for IHV-developed drivers
  NULL, // ImageHandle, to be overwritten by
        // EfiLibInstallDriverBindingComponentName2() in VirtioPciEntryPoint()
  NULL  // DriverBindingHandle, ditto
};


//
// The purpose of the following scaffolding (EFI_COMPONENT_NAME_PROTOCOL and
// EFI_COMPONENT_NAME2_PROTOCOL implementation) is to format the driver's name
// in English, for display on standard console devices. This is recommended for
// UEFI drivers that follow the UEFI Driver Model. Refer to the Driver Writer's
// Guide for UEFI 2.3.1 v1.01, 11 UEFI Driver and Controller Names.
//
STATIC
EFI_UNICODE_STRING_TABLE mDriverNameTable[] = {
  { "eng;en", L"Virtio PCI Driver" },
  { NULL,     NULL                   }
};

STATIC
EFI_COMPONENT_NAME_PROTOCOL gComponentName;

EFI_STATUS
EFIAPI
VirtioPciGetDriverName (
  IN  EFI_COMPONENT_NAME_PROTOCOL *This,
  IN  CHAR8                       *Language,
  OUT CHAR16                      **DriverName
  )
{
  return LookupUnicodeString2 (
           Language,
           This->SupportedLanguages,
           mDriverNameTable,
           DriverName,
           (BOOLEAN)(This == &gComponentName) // Iso639Language
           );
}

EFI_STATUS
EFIAPI
VirtioPciGetDeviceName (
  IN  EFI_COMPONENT_NAME_PROTOCOL *This,
  IN  EFI_HANDLE                  DeviceHandle,
  IN  EFI_HANDLE                  ChildHandle,
  IN  CHAR8                       *Language,
  OUT CHAR16                      **ControllerName
  )
{
  return EFI_UNSUPPORTED;
}

STATIC
EFI_COMPONENT_NAME_PROTOCOL gComponentName = {
  &VirtioPciGetDriverName,
  &VirtioPciGetDeviceName,
  "eng" // SupportedLanguages, ISO 639-2 language codes
};

STATIC
EFI_COMPONENT_NAME2_PROTOCOL gComponentName2 = {
  (EFI_COMPONENT_NAME2_GET_DRIVER_NAME)     &VirtioPciGetDriverName,
  (EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME) &VirtioPciGetDeviceName,
  "en" // SupportedLanguages, RFC 4646 language codes
};


//
// Entry point of this driver.
//
EFI_STATUS
EFIAPI
VirtioPciDeviceEntryPoint (
  IN EFI_HANDLE       ImageHandle,
  IN EFI_SYSTEM_TABLE *SystemTable
  )
{
  return EfiLibInstallDriverBindingComponentName2 (
           ImageHandle,
           SystemTable,
           &gDriverBinding,
           ImageHandle,
           &gComponentName,
           &gComponentName2
           );
}