hardware.h revision 65820e4d7a0b89108b194284b94f6f82d28a875c
1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#ifndef ANDROID_INCLUDE_HARDWARE_HARDWARE_H 18#define ANDROID_INCLUDE_HARDWARE_HARDWARE_H 19 20#include <stdint.h> 21#include <sys/cdefs.h> 22 23#include <cutils/native_handle.h> 24#include <system/graphics.h> 25 26__BEGIN_DECLS 27 28/* 29 * Value for the hw_module_t.tag field 30 */ 31 32#define MAKE_TAG_CONSTANT(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 33 34#define HARDWARE_MODULE_TAG MAKE_TAG_CONSTANT('H', 'W', 'M', 'T') 35#define HARDWARE_DEVICE_TAG MAKE_TAG_CONSTANT('H', 'W', 'D', 'T') 36 37#define HARDWARE_MAKE_API_VERSION(maj,min) \ 38 ((((maj) & 0xff) << 8) | ((min) & 0xff)) 39 40/* 41 * The current HAL API version. 42 * 43 * All module implementations must set the hw_module_t.hal_api_version field 44 * to this value when declaring the module with HAL_MODULE_INFO_SYM. 45 * 46 * Note that previous implementations have always set this field to 0. 47 * Therefore, libhardware HAL API will always consider versions 0.0 and 1.0 48 * to be 100% binary compatible. 49 * 50 */ 51#define HARDWARE_HAL_API_VERSION HARDWARE_MAKE_API_VERSION(1, 0) 52 53/* 54 * Helper macro for module implementors. 55 * 56 * Use this macro to set the hw_module_t.module_api_version field. 57 */ 58#define HARDWARE_MODULE_API_VERSION(maj,min) HARDWARE_MAKE_API_VERSION(maj,min) 59 60struct hw_module_t; 61struct hw_module_methods_t; 62struct hw_device_t; 63 64/** 65 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM 66 * and the fields of this data structure must begin with hw_module_t 67 * followed by module specific information. 68 */ 69typedef struct hw_module_t { 70 /** tag must be initialized to HARDWARE_MODULE_TAG */ 71 uint32_t tag; 72 73 /** 74 * The API version of the implemented module. The module owner is 75 * responsible for updating the version when a module interface has 76 * changed. 77 * 78 * The derived modules such as gralloc and audio own and manage this field. 79 * The module user must interpret the version field to decide whether or 80 * not to inter-operate with the supplied module implementation. 81 * For example, SurfaceFlinger is responsible for making sure that 82 * it knows how to manage different versions of the gralloc-module API, 83 * and AudioFlinger must know how to do the same for audio-module API. 84 * 85 * The module API version should include a major and a minor component. 86 * For example, version 1.0 could be represented as 0x0100. This format 87 * implies that versions 0x0100-0x01ff are all API-compatible. 88 * 89 * In the future, libhardware will expose a hw_get_module_version() 90 * (or equivalent) function that will take minimum/maximum supported 91 * versions as arguments and would be able to reject modules with 92 * versions outside of the supplied range. 93 */ 94 uint16_t module_api_version; 95#define version_major module_api_version 96 /** 97 * version_major/version_minor defines are supplied here for temporary 98 * source code compatibility. They will be removed in the next version. 99 * ALL clients must convert to the new version format. 100 */ 101 102 /** 103 * The API version of the HAL module interface. This is meant to 104 * version the hw_module_t, hw_module_methods_t, and hw_device_t 105 * structures and definitions. 106 * 107 * The HAL interface owns this field. Module users/implementations 108 * must NOT rely on this value for version information. 109 * 110 * Presently, 0 is the only valid value. 111 */ 112 uint16_t hal_api_version; 113#define version_minor hal_api_version 114 115 /** Identifier of module */ 116 const char *id; 117 118 /** Name of this module */ 119 const char *name; 120 121 /** Author/owner/implementor of the module */ 122 const char *author; 123 124 /** Modules methods */ 125 struct hw_module_methods_t* methods; 126 127 /** module's dso */ 128 void* dso; 129 130 /** padding to 128 bytes, reserved for future use */ 131 uint32_t reserved[32-7]; 132 133} hw_module_t; 134 135typedef struct hw_module_methods_t { 136 /** Open a specific device */ 137 int (*open)(const struct hw_module_t* module, const char* id, 138 struct hw_device_t** device); 139 140} hw_module_methods_t; 141 142/** 143 * Every device data structure must begin with hw_device_t 144 * followed by module specific public methods and attributes. 145 */ 146typedef struct hw_device_t { 147 /** tag must be initialized to HARDWARE_DEVICE_TAG */ 148 uint32_t tag; 149 150 /** 151 * Version of the module-specific device API. This value is used by 152 * the derived-module user to manage different device implementations. 153 * 154 * The module user is responsible for checking the module_api_version 155 * and device version fields to ensure that the user is capable of 156 * communicating with the specific module implementation. 157 * 158 * One module can support multiple devices with different versions. This 159 * can be useful when a device interface changes in an incompatible way 160 * but it is still necessary to support older implementations at the same 161 * time. One such example is the Camera 2.0 API. 162 * 163 * This field is interpreted by the module user and is ignored by the 164 * HAL interface itself. 165 */ 166 uint32_t version; 167 168 /** reference to the module this device belongs to */ 169 struct hw_module_t* module; 170 171 /** padding reserved for future use */ 172 uint32_t reserved[12]; 173 174 /** Close this device */ 175 int (*close)(struct hw_device_t* device); 176 177} hw_device_t; 178 179/** 180 * Name of the hal_module_info 181 */ 182#define HAL_MODULE_INFO_SYM HMI 183 184/** 185 * Name of the hal_module_info as a string 186 */ 187#define HAL_MODULE_INFO_SYM_AS_STR "HMI" 188 189/** 190 * Get the module info associated with a module by id. 191 * 192 * @return: 0 == success, <0 == error and *module == NULL 193 */ 194int hw_get_module(const char *id, const struct hw_module_t **module); 195 196/** 197 * Get the module info associated with a module instance by class 'class_id' 198 * and instance 'inst'. 199 * 200 * Some modules types necessitate multiple instances. For example audio supports 201 * multiple concurrent interfaces and thus 'audio' is the module class 202 * and 'primary' or 'a2dp' are module interfaces. This implies that the files 203 * providing these modules would be named audio.primary.<variant>.so and 204 * audio.a2dp.<variant>.so 205 * 206 * @return: 0 == success, <0 == error and *module == NULL 207 */ 208int hw_get_module_by_class(const char *class_id, const char *inst, 209 const struct hw_module_t **module); 210 211__END_DECLS 212 213#endif /* ANDROID_INCLUDE_HARDWARE_HARDWARE_H */ 214