audk/ArmPkg/Drivers/ArmScmiDxe/Scmi.c

/** @file

  Copyright (c) 2017-2018, Arm Limited. All rights reserved.

  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.

  System Control and Management Interface V1.0
    http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/
    DEN0056A_System_Control_and_Management_Interface.pdf
**/

#include <Library/ArmMtlLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>

#include "ScmiPrivate.h"

// Arbitrary timeout value 20ms.
#define  RESPONSE_TIMEOUT  20000

/** Return a pointer to the message payload.

  @param[out] Payload         Holds pointer to the message payload.

  @retval EFI_SUCCESS         Payload holds a valid message payload pointer.
  @retval EFI_TIMEOUT         Time out error if MTL channel is busy.
  @retval EFI_UNSUPPORTED     If MTL channel is unsupported.
**/
EFI_STATUS
ScmiCommandGetPayload (
  OUT UINT32** Payload
  )
{
  EFI_STATUS   Status;
  MTL_CHANNEL  *Channel;

  // Get handle to the Channel.
  Status = MtlGetChannel (MTL_CHANNEL_TYPE_LOW, &Channel);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  // Payload will not be populated until channel is free.
  Status = MtlWaitUntilChannelFree (Channel, RESPONSE_TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  // Get the address of the payload.
  *Payload = MtlGetChannelPayload (Channel);

  return EFI_SUCCESS;
}

/** Execute a SCMI command and receive a response.

  This function uses a MTL channel to transfer message to SCP
  and waits for a response.

  @param[in]   Command      Pointer to the SCMI command (Protocol ID
                            and Message ID)

  @param[in,out] PayloadLength   SCMI command message length.

  @param[out] OPTIONAL  ReturnValues   Pointer to SCMI response.

  @retval OUT EFI_SUCCESS       Command sent and message received successfully.
  @retval OUT EFI_UNSUPPORTED   Channel not supported.
  @retval OUT EFI_TIMEOUT       Timeout on the channel.
  @retval OUT EFI_DEVICE_ERROR  Channel not ready.
  @retval OUT EFI_DEVICE_ERROR  Message Header corrupted.
  @retval OUT EFI_DEVICE_ERROR  SCMI error.
**/
EFI_STATUS
ScmiCommandExecute (
  IN     SCMI_COMMAND  *Command,
  IN OUT UINT32        *PayloadLength,
  OUT    UINT32       **ReturnValues OPTIONAL
  )
{
  EFI_STATUS             Status;
  SCMI_MESSAGE_RESPONSE  *Response;
  UINT32                 MessageHeader;
  UINT32                 ResponseHeader;
  MTL_CHANNEL            *Channel;

  ASSERT (PayloadLength != NULL);

  Status = MtlGetChannel (MTL_CHANNEL_TYPE_LOW, &Channel);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  // Fill in message header.
  MessageHeader = SCMI_MESSAGE_HEADER (
                    Command->MessageId,
                    SCMI_MESSAGE_TYPE_COMMAND,
                    Command->ProtocolId
                    );

  // Send payload using MTL channel.
  Status = MtlSendMessage (
             Channel,
             MessageHeader,
             *PayloadLength
             );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  // Wait for the response on the channel.
  Status = MtlReceiveMessage (Channel, &ResponseHeader, PayloadLength);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  // SCMI must return MessageHeader unmodified.
  if (MessageHeader != ResponseHeader) {
    ASSERT (FALSE);
    return EFI_DEVICE_ERROR;
  }

  Response = (SCMI_MESSAGE_RESPONSE*)MtlGetChannelPayload (Channel);

  if (Response->Status != SCMI_SUCCESS) {
    DEBUG ((DEBUG_ERROR, "SCMI error: ProtocolId = 0x%x, MessageId = 0x%x, error = %d\n",
      Command->ProtocolId,
      Command->MessageId,
      Response->Status
      ));

    ASSERT (FALSE);
    return EFI_DEVICE_ERROR;
  }

  if (ReturnValues != NULL) {
    *ReturnValues = Response->ReturnValues;
  }

  return EFI_SUCCESS;
}

/** Internal common function useful for common protocol discovery messages.

  @param[in] ProtocolId    Protocol Id of the the protocol.
  @param[in] MesaageId     Message Id of the message.

  @param[out] ReturnValues SCMI response return values.

  @retval EFI_SUCCESS      Success with valid return values.
  @retval EFI_DEVICE_ERROR SCMI error.
  @retval !(EFI_SUCCESS)   Other errors.
**/
STATIC
EFI_STATUS
ScmiProtocolDiscoveryCommon (
  IN SCMI_PROTOCOL_ID  ProtocolId,
  IN SCMI_MESSAGE_ID   MessageId,
  OUT UINT32           **ReturnValues
  )
{
  SCMI_COMMAND  Command;
  UINT32        PayloadLength = 0;

  Command.ProtocolId = ProtocolId;
  Command.MessageId  = MessageId;

  return ScmiCommandExecute (
           &Command,
           &PayloadLength,
           ReturnValues
           );
}

/** Return protocol version from SCP for a given protocol ID.

  @param[in]  Protocol ID    Protocol ID.
  @param[out] Version        Pointer to version of the protocol.

  @retval EFI_SUCCESS       Version holds a valid version received
                             from the SCP.
  @retval EFI_DEVICE_ERROR  SCMI error.
  @retval !(EFI_SUCCESS)    Other errors.
**/
EFI_STATUS
ScmiGetProtocolVersion (
  IN  SCMI_PROTOCOL_ID  ProtocolId,
  OUT UINT32            *Version
  )
{
  EFI_STATUS             Status;
  UINT32                 *ProtocolVersion;

  Status = ScmiProtocolDiscoveryCommon (
             ProtocolId,
             SCMI_MESSAGE_ID_PROTOCOL_VERSION,
             (UINT32**)&ProtocolVersion
             );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  *Version = *ProtocolVersion;

  return EFI_SUCCESS;
}

/** Return protocol attributes from SCP for a given protocol ID.

  @param[in]  Protocol ID    Protocol ID.
  @param[out] ReturnValues   Pointer to attributes of the protocol.

  @retval EFI_SUCCESS       ReturnValues points to protocol attributes.
  @retval EFI_DEVICE_ERROR  SCMI error.
  @retval !(EFI_SUCCESS)    Other errors.
**/
EFI_STATUS
ScmiGetProtocolAttributes (
  IN  SCMI_PROTOCOL_ID  ProtocolId,
  OUT UINT32            **ReturnValues
  )
{
  return ScmiProtocolDiscoveryCommon (
           ProtocolId,
           SCMI_MESSAGE_ID_PROTOCOL_ATTRIBUTES,
           ReturnValues
           );
}

/** Return protocol message attributes from SCP for a given protocol ID.

  @param[in]  Protocol ID    Protocol ID.
  @param[out] Attributes     Pointer to attributes of the protocol.

  @retval EFI_SUCCESS       ReturnValues points to protocol message attributes.
  @retval EFI_DEVICE_ERROR  SCMI error.
  @retval !(EFI_SUCCESS)    Other errors.
**/
EFI_STATUS
ScmiGetProtocolMessageAttributes (
  IN  SCMI_PROTOCOL_ID  ProtocolId,
  OUT UINT32            **ReturnValues
  )
{
  return ScmiProtocolDiscoveryCommon (
           ProtocolId,
           SCMI_MESSAGE_ID_PROTOCOL_MESSAGE_ATTRIBUTES,
           ReturnValues
           );
}