Re: [PATCH v2 15/21] DynamicTablesPkg: AML code generation for a Method

["Sami Mujawar" <sami.mujawar@arm.com>]

Hi Pierre,

Thank you for adding documentation for the steps for generating a Method.

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

Regards,

Sami Mujawar

On 07/10/2021 04:32 PM, Pierre.Gondois@arm.com wrote:
> From: Pierre Gondois <Pierre.Gondois@arm.com>
>
> Add AmlCodeGenMethod() to generate code for a control method.
>
> AmlCodeGenMethod ("MET0", 1, TRUE, 3, ParentNode, NewObjectNode)
> is equivalent of the following ASL code:
>      Method(MET0, 1, Serialized, 3) {}
>
> Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
> ---
>   .../Common/AmlLib/CodeGen/AmlCodeGen.c        | 184 ++++++++++++++++++
>   1 file changed, 184 insertions(+)
>
> diff --git a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> index da80e9d77cc2..dd519bc67007 100644
> --- a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> +++ b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> @@ -970,3 +970,187 @@ error_handler1:
>
>     return Status;
>   }
> +
> +/** AML code generation for a Method object node.
> +
> +  AmlCodeGenMethod ("MET0", 1, TRUE, 3, ParentNode, NewObjectNode) is
> +  equivalent of the following ASL code:
> +    Method(MET0, 1, Serialized, 3) {}
> +
> +  ACPI 6.4, s20.2.5.2 "Named Objects Encoding":
> +    DefMethod := MethodOp PkgLength NameString MethodFlags TermList
> +    MethodOp := 0x14
> +
> +  The ASL parameters "ReturnType" and "ParameterTypes" are not asked
> +  in this function. They are optional parameters in ASL.
> +
> +  @param [in]  NameString     The new Method's name.
> +                              Must be a NULL-terminated ASL NameString
> +                              e.g.: "MET0", "_SB.MET0", etc.
> +                              The input string is copied.
> +  @param [in]  NumArgs        Number of arguments.
> +                              Must be 0 <= NumArgs <= 6.
> +  @param [in]  IsSerialized   TRUE is equivalent to Serialized.
> +                              FALSE is equivalent to NotSerialized.
> +                              Default is NotSerialized in ASL spec.
> +  @param [in]  SyncLevel      Synchronization level for the method.
> +                              Must be 0 <= SyncLevel <= 15.
> +                              Default is 0 in ASL.
> +  @param [in]  ParentNode     If provided, set ParentNode as the parent
> +                              of the node created.
> +  @param [out] NewObjectNode  If success, contains the created node.
> +
> +  @retval EFI_SUCCESS             Success.
> +  @retval EFI_INVALID_PARAMETER   Invalid parameter.
> +  @retval EFI_OUT_OF_RESOURCES    Failed to allocate memory.
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +AmlCodeGenMethod (
> +  IN  CONST CHAR8              * NameString,
> +  IN        UINT8                NumArgs,
> +  IN        BOOLEAN              IsSerialized,
> +  IN        UINT8                SyncLevel,
> +  IN        AML_NODE_HEADER    * ParentNode,     OPTIONAL
> +  OUT       AML_OBJECT_NODE   ** NewObjectNode   OPTIONAL
> +  )
> +{
> +  EFI_STATUS        Status;
> +  UINT32            PkgLen;
> +  UINT8             Flags;
> +  AML_OBJECT_NODE * ObjectNode;
> +  AML_DATA_NODE   * DataNode;
> +  CHAR8           * AmlNameString;
> +  UINT32            AmlNameStringSize;
> +
> +  if ((NameString == NULL)    ||
> +      (NumArgs > 6)           ||
> +      (SyncLevel > 15)        ||
> +      ((ParentNode == NULL) && (NewObjectNode == NULL))) {
> +    ASSERT (0);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  ObjectNode = NULL;
> +  DataNode = NULL;
> +
> +  // ACPI 6.4, s20.2.5.2 "Named Objects Encoding":
> +  //   DefMethod := MethodOp PkgLength NameString MethodFlags TermList
> +  //   MethodOp := 0x14
> +  // So:
> +  //  1- Create the NameString
> +  //  2- Compute the size to write in the PkgLen
> +  //  3- Create nodes for the NameString and Method object node
> +  //  4- Set the NameString DataNode as a fixed argument
> +  //  5- Create and link the MethodFlags node
> +
> +  // 1- Create the NameString
> +  Status = ConvertAslNameToAmlName (NameString, &AmlNameString);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    return Status;
> +  }
> +
> +  Status = AmlGetNameStringSize (AmlNameString, &AmlNameStringSize);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler1;
> +  }
> +
> +  // 2- Compute the size to write in the PkgLen
> +  //    Add 1 byte (ByteData) for MethodFlags.
> +  Status = AmlComputePkgLength (AmlNameStringSize + 1, &PkgLen);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler1;
> +  }
> +
> +  //  3- Create nodes for the NameString and Method object node
> +  Status = AmlCreateObjectNode (
> +             AmlGetByteEncodingByOpCode (AML_METHOD_OP, 0),
> +             PkgLen,
> +             &ObjectNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler1;
> +  }
> +
> +  Status = AmlCreateDataNode (
> +             EAmlNodeDataTypeNameString,
> +             (UINT8*)AmlNameString,
> +             AmlNameStringSize,
> +             &DataNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler2;
> +  }
> +
> +  //  4- Set the NameString DataNode as a fixed argument
> +  Status = AmlSetFixedArgument (
> +             ObjectNode,
> +             EAmlParseIndexTerm0,
> +             (AML_NODE_HEADER*)DataNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler2;
> +  }
> +
> +  DataNode = NULL;
> +
> +  //  5- Create and link the MethodFlags node
> +  Flags = NumArgs                   |
> +          (IsSerialized ? BIT3 : 0) |
> +          (SyncLevel << 4);
> +
> +  Status = AmlCreateDataNode (EAmlNodeDataTypeUInt, &Flags, 1, &DataNode);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler2;
> +  }
> +
> +  Status = AmlSetFixedArgument (
> +             ObjectNode,
> +             EAmlParseIndexTerm1,
> +             (AML_NODE_HEADER*)DataNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler2;
> +  }
> +
> +  // Data node is attached so set the pointer to
> +  // NULL to ensure correct error handling.
> +  DataNode = NULL;
> +
> +  Status = LinkNode (
> +             ObjectNode,
> +             ParentNode,
> +             NewObjectNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler2;
> +  }
> +
> +  // Free AmlNameString before returning as it is copied
> +  // in the call to AmlCreateDataNode().
> +  goto error_handler1;
> +
> +error_handler2:
> +  if (ObjectNode != NULL) {
> +    AmlDeleteTree ((AML_NODE_HEADER*)ObjectNode);
> +  }
> +  if (DataNode != NULL) {
> +    AmlDeleteTree ((AML_NODE_HEADER*)DataNode);
> +  }
> +
> +error_handler1:
> +  if (AmlNameString != NULL) {
> +    FreePool (AmlNameString);
> +  }
> +  return Status;
> +}

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