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* Copyright (C) 2008 The Android Open Source Project
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include <stdint.h>
#include <sys/cdefs.h>
* Value for the hw_module_t.tag field
#define MAKE_TAG_CONSTANT(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D))
#define HARDWARE_MAKE_API_VERSION(maj,min) \
((((maj) & 0xff) << 8) | ((min) & 0xff))
#define HARDWARE_MAKE_API_VERSION_2(maj,min,hdr) \
((((maj) & 0xff) << 24) | (((min) & 0xff) << 16) | ((hdr) & 0xffff))
* The current HAL API version.
* All module implementations must set the hw_module_t.hal_api_version field
* to this value when declaring the module with HAL_MODULE_INFO_SYM.
* Note that previous implementations have always set this field to 0.
* Therefore, libhardware HAL API will always consider versions 0.0 and 1.0
* to be 100% binary compatible.
* Helper macros for module implementors.
* The derived modules should provide convenience macros for supported
* versions so that implementations can explicitly specify module/device
* versions at definition time.
* Use this macro to set the hw_module_t.module_api_version field.
* Use this macro to set the hw_device_t.version field
struct hw_module_t;
struct hw_module_methods_t;
struct hw_device_t;
* Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
* and the fields of this data structure must begin with hw_module_t
* followed by module specific information.
typedef struct hw_module_t {
/** tag must be initialized to HARDWARE_MODULE_TAG */
uint32_t tag;
* The API version of the implemented module. The module owner is
* responsible for updating the version when a module interface has
* changed.
* The derived modules such as gralloc and audio own and manage this field.
* The module user must interpret the version field to decide whether or
* not to inter-operate with the supplied module implementation.
* For example, SurfaceFlinger is responsible for making sure that
* it knows how to manage different versions of the gralloc-module API,
* and AudioFlinger must know how to do the same for audio-module API.
* The module API version should include a major and a minor component.
* For example, version 1.0 could be represented as 0x0100. This format
* implies that versions 0x0100-0x01ff are all API-compatible.
* In the future, libhardware will expose a hw_get_module_version()
* (or equivalent) function that will take minimum/maximum supported
* versions as arguments and would be able to reject modules with
* versions outside of the supplied range.
uint16_t module_api_version;
#define version_major module_api_version
* version_major/version_minor defines are supplied here for temporary
* source code compatibility. They will be removed in the next version.
* ALL clients must convert to the new version format.
* The API version of the HAL module interface. This is meant to
* version the hw_module_t, hw_module_methods_t, and hw_device_t
* structures and definitions.
* The HAL interface owns this field. Module users/implementations
* must NOT rely on this value for version information.
* Presently, 0 is the only valid value.
uint16_t hal_api_version;
#define version_minor hal_api_version
/** Identifier of module */
const char *id;
/** Name of this module */
const char *name;
/** Author/owner/implementor of the module */
const char *author;
/** Modules methods */
struct hw_module_methods_t* methods;
/** module's dso */
void* dso;
/** padding to 128 bytes, reserved for future use */
uint32_t reserved[32-7];
} hw_module_t;
typedef struct hw_module_methods_t {
/** Open a specific device */
int (*open)(const struct hw_module_t* module, const char* id,
struct hw_device_t** device);
} hw_module_methods_t;
* Every device data structure must begin with hw_device_t
* followed by module specific public methods and attributes.
typedef struct hw_device_t {
/** tag must be initialized to HARDWARE_DEVICE_TAG */
uint32_t tag;
* Version of the module-specific device API. This value is used by
* the derived-module user to manage different device implementations.
* The module user is responsible for checking the module_api_version
* and device version fields to ensure that the user is capable of
* communicating with the specific module implementation.
* One module can support multiple devices with different versions. This
* can be useful when a device interface changes in an incompatible way
* but it is still necessary to support older implementations at the same
* time. One such example is the Camera 2.0 API.
* This field is interpreted by the module user and is ignored by the
* HAL interface itself.
uint32_t version;
/** reference to the module this device belongs to */
struct hw_module_t* module;
/** padding reserved for future use */
uint32_t reserved[12];
/** Close this device */
int (*close)(struct hw_device_t* device);
} hw_device_t;
* Name of the hal_module_info
* Name of the hal_module_info as a string
* Get the module info associated with a module by id.
* @return: 0 == success, <0 == error and *module == NULL
int hw_get_module(const char *id, const struct hw_module_t **module);
* Get the module info associated with a module instance by class 'class_id'
* and instance 'inst'.
* Some modules types necessitate multiple instances. For example audio supports
* multiple concurrent interfaces and thus 'audio' is the module class
* and 'primary' or 'a2dp' are module interfaces. This implies that the files
* providing these modules would be named audio.primary.<variant>.so and
* audio.a2dp.<variant>.so
* @return: 0 == success, <0 == error and *module == NULL
int hw_get_module_by_class(const char *class_id, const char *inst,
const struct hw_module_t **module);