7. UEFI的protocol服务

Protocol是什么

Protocol就是对每一类设备 抽象后得总称。 IHANDLE就是一个个设备句柄。

Protocol得描述

UEFI在扫描总线后，会 为每一个设备建立一个Controller对象，用于描述和控制这个设备
这个 对象句柄就是 EFI_HANDLE（UEFI中，这个句柄事IHANDLE）

EFI_HANDLE 对象句柄描述

typedef struct {
  UINTN               Signature;            // handle得类别
  LIST_ENTRY          AllHandles;            // 所有设备得IHANDLE 链表， 也就是 所有设备链，遍历设备用。
  LIST_ENTRY          Protocols;      // Handle得Protocol链表，查找自己得protocol使用
  UINTN               LocateRequest;
  UINT64              Key;
} IHANDLE;

Prorocol接口描述

///
/// PROTOCOL_INTERFACE - each protocol installed on a handle is tracked
/// with a protocol interface structure
///
typedef struct {
  UINTN                       Signature;
  /// Link on IHANDLE.Protocols
  LIST_ENTRY                  Link;   
  /// Back pointer
  IHANDLE                     *Handle;  
  /// Link on PROTOCOL_ENTRY.Protocols
  LIST_ENTRY                  ByProtocol; 
  /// The protocol ID
  PROTOCOL_ENTRY              *Protocol;        //   可获取PROTOCOL得GUID
  /// The interface value
  VOID                        *Interface;     // 可获取protocol实例
  /// OPEN_PROTOCOL_DATA list
  LIST_ENTRY                  OpenList;       
  UINTN                       OpenListCount;
} PROTOCOL_INTERFACE;

EFI_HANDLE和Protocol得关系图

protocol得使用

gBS中protocol得方法

EFI_BOOT_SERVICES  *gBS;
typedef struct {  // 协议相关
  //
  // ！！！ Open and Close Protocol Services  最常用得就是 打开，使用，关闭 protocol
  //
  EFI_OPEN_PROTOCOL                 OpenProtocol;
  EFI_CLOSE_PROTOCOL                CloseProtocol;
    EFI_HANDLE_PROTOCOL               HandleProtocol;
  // Protocol Handler Services
  EFI_INSTALL_PROTOCOL_INTERFACE    InstallProtocolInterface;
  EFI_REINSTALL_PROTOCOL_INTERFACE  ReinstallProtocolInterface;
  EFI_UNINSTALL_PROTOCOL_INTERFACE  UninstallProtocolInterface;
  EFI_HANDLE_PROTOCOL               HandleProtocol;
  VOID                              *Reserved;
  EFI_REGISTER_PROTOCOL_NOTIFY      RegisterProtocolNotify;
  EFI_LOCATE_HANDLE                 LocateHandle;
  EFI_LOCATE_DEVICE_PATH            LocateDevicePath;
  EFI_INSTALL_CONFIGURATION_TABLE   InstallConfigurationTable;
  // Library Services
  EFI_PROTOCOLS_PER_HANDLE          ProtocolsPerHandle;
  EFI_LOCATE_HANDLE_BUFFER          LocateHandleBuffer;    
  EFI_LOCATE_PROTOCOL               LocateProtocol;
  EFI_INSTALL_MULTIPLE_PROTOCOL_INTERFACES    InstallMultipleProtocolInterfaces;
  EFI_UNINSTALL_MULTIPLE_PROTOCOL_INTERFACES  UninstallMultipleProtocolInterfaces;
}

EFI_STATUS

  @retval EFI_SUCCESS           An item was added to the open list for the protocol interface, and the
                                protocol interface was returned in Interface.        成功打开
  @retval EFI_UNSUPPORTED       Handle does not support Protocol.            handle不支持Protocol
  @retval EFI_INVALID_PARAMETER One or more parameters are invalid.        无效参数
  @retval EFI_ACCESS_DENIED     Required attributes can't be supported in current environment.   当前环境不支持attribute属性打开
  @retval EFI_ALREADY_STARTED   Item on the open list already has requierd attributes whose agent  Protocol已经被同一个AgentHandle打开
                                handle is the same as AgentHandle.

OPEN 和 CLOSE

/**
  Queries a handle to determine if it supports a specified protocol. If the protocol is supported by the
  handle, it opens the protocol on behalf of the calling agent.
  @param[in]   Handle           The handle for the protocol interface that is being opened.
  @param[in]   Protocol         The published unique identifier of the protocol.
  @param[out]  Interface        Supplies the address where a pointer to the corresponding Protocol
                                Interface is returned.
  @param[in]   AgentHandle      The handle of the agent that is opening the protocol interface
                                specified by Protocol and Interface.
  @param[in]   ControllerHandle If the agent that is opening a protocol is a driver that follows the
                                UEFI Driver Model, then this parameter is the controller handle
                                that requires the protocol interface. If the agent does not follow
                                the UEFI Driver Model, then this parameter is optional and may
                                be NULL.
  @param[in]   Attributes       The open mode of the protocol interface specified by Handle
                                and Protocol.
  @retval EFI_SUCCESS           An item was added to the open list for the protocol interface, and the
                                protocol interface was returned in Interface.
  @retval EFI_UNSUPPORTED       Handle does not support Protocol.
  @retval EFI_INVALID_PARAMETER One or more parameters are invalid.
  @retval EFI_ACCESS_DENIED     Required attributes can't be supported in current environment.
  @retval EFI_ALREADY_STARTED   Item on the open list already has requierd attributes whose agent
                                handle is the same as AgentHandle.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_OPEN_PROTOCOL)(
  IN  EFI_HANDLE                Handle,                                // 指定得handle，
  IN  EFI_GUID                  *Protocol,                        // 要打开GUID对应得protocol
  OUT VOID                      **Interface, OPTIONAL    // 返回打开得protocol对象
  IN  EFI_HANDLE                AgentHandle,                    // 打开protocol得Image
  IN  EFI_HANDLE                ControllerHandle,            // 使用此protocol得控制器
  IN  UINT32                    Attributes                        // 打开protocol得方式
  );
typedef
EFI_STATUS
(EFIAPI *EFI_CLOSE_PROTOCOL)(
  IN EFI_HANDLE               Handle,
  IN EFI_GUID                 *Protocol,
  IN EFI_HANDLE               AgentHandle,
  IN EFI_HANDLE               ControllerHandle
  );
typedef
EFI_STATUS
(EFIAPI *EFI_HANDLE_PROTOCOL)(
  IN  EFI_HANDLE               Handle,
  IN  EFI_GUID                 *Protocol,
  OUT VOID                     **Interface
  );

Attributes打开属性

#define EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL  0x00000001
#define EFI_OPEN_PROTOCOL_GET_PROTOCOL        0x00000002
#define EFI_OPEN_PROTOCOL_TEST_PROTOCOL       0x00000004
#define EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER 0x00000008
#define EFI_OPEN_PROTOCOL_BY_DRIVER           0x00000010
#define EFI_OPEN_PROTOCOL_EXCLUSIVE           0x00000020

protocol得开发