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 macros for module implementors. 55 * 56 * The derived modules should provide convenience macros for supported 57 * versions so that implementations can explicitly specify module/device 58 * versions at definition time. 59 * 60 * Use this macro to set the hw_module_t.module_api_version field. 61 */ 62 #define HARDWARE_MODULE_API_VERSION(maj,min) HARDWARE_MAKE_API_VERSION(maj,min) 63 64 /* 65 * Use this macro to set the hw_device_t.version field 66 */ 67 #define HARDWARE_DEVICE_API_VERSION(maj,min) HARDWARE_MAKE_API_VERSION(maj,min) 68 69 struct hw_module_t; 70 struct hw_module_methods_t; 71 struct hw_device_t; 72 73 /** 74 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM 75 * and the fields of this data structure must begin with hw_module_t 76 * followed by module specific information. 77 */ 78 typedef struct hw_module_t { 79 /** tag must be initialized to HARDWARE_MODULE_TAG */ 80 uint32_t tag; 81 82 /** 83 * The API version of the implemented module. The module owner is 84 * responsible for updating the version when a module interface has 85 * changed. 86 * 87 * The derived modules such as gralloc and audio own and manage this field. 88 * The module user must interpret the version field to decide whether or 89 * not to inter-operate with the supplied module implementation. 90 * For example, SurfaceFlinger is responsible for making sure that 91 * it knows how to manage different versions of the gralloc-module API, 92 * and AudioFlinger must know how to do the same for audio-module API. 93 * 94 * The module API version should include a major and a minor component. 95 * For example, version 1.0 could be represented as 0x0100. This format 96 * implies that versions 0x0100-0x01ff are all API-compatible. 97 * 98 * In the future, libhardware will expose a hw_get_module_version() 99 * (or equivalent) function that will take minimum/maximum supported 100 * versions as arguments and would be able to reject modules with 101 * versions outside of the supplied range. 102 */ 103 uint16_t module_api_version; 104 #define version_major module_api_version 105 /** 106 * version_major/version_minor defines are supplied here for temporary 107 * source code compatibility. They will be removed in the next version. 108 * ALL clients must convert to the new version format. 109 */ 110 111 /** 112 * The API version of the HAL module interface. This is meant to 113 * version the hw_module_t, hw_module_methods_t, and hw_device_t 114 * structures and definitions. 115 * 116 * The HAL interface owns this field. Module users/implementations 117 * must NOT rely on this value for version information. 118 * 119 * Presently, 0 is the only valid value. 120 */ 121 uint16_t hal_api_version; 122 #define version_minor hal_api_version 123 124 /** Identifier of module */ 125 const char *id; 126 127 /** Name of this module */ 128 const char *name; 129 130 /** Author/owner/implementor of the module */ 131 const char *author; 132 133 /** Modules methods */ 134 struct hw_module_methods_t* methods; 135 136 /** module's dso */ 137 void* dso; 138 139 /** padding to 128 bytes, reserved for future use */ 140 uint32_t reserved[32-7]; 141 142 } hw_module_t; 143 144 typedef struct hw_module_methods_t { 145 /** Open a specific device */ 146 int (*open)(const struct hw_module_t* module, const char* id, 147 struct hw_device_t** device); 148 149 } hw_module_methods_t; 150 151 /** 152 * Every device data structure must begin with hw_device_t 153 * followed by module specific public methods and attributes. 154 */ 155 typedef struct hw_device_t { 156 /** tag must be initialized to HARDWARE_DEVICE_TAG */ 157 uint32_t tag; 158 159 /** 160 * Version of the module-specific device API. This value is used by 161 * the derived-module user to manage different device implementations. 162 * 163 * The module user is responsible for checking the module_api_version 164 * and device version fields to ensure that the user is capable of 165 * communicating with the specific module implementation. 166 * 167 * One module can support multiple devices with different versions. This 168 * can be useful when a device interface changes in an incompatible way 169 * but it is still necessary to support older implementations at the same 170 * time. One such example is the Camera 2.0 API. 171 * 172 * This field is interpreted by the module user and is ignored by the 173 * HAL interface itself. 174 */ 175 uint32_t version; 176 177 /** reference to the module this device belongs to */ 178 struct hw_module_t* module; 179 180 /** padding reserved for future use */ 181 uint32_t reserved[12]; 182 183 /** Close this device */ 184 int (*close)(struct hw_device_t* device); 185 186 } hw_device_t; 187 188 /** 189 * Name of the hal_module_info 190 */ 191 #define HAL_MODULE_INFO_SYM HMI 192 193 /** 194 * Name of the hal_module_info as a string 195 */ 196 #define HAL_MODULE_INFO_SYM_AS_STR "HMI" 197 198 /** 199 * Get the module info associated with a module by id. 200 * 201 * @return: 0 == success, <0 == error and *module == NULL 202 */ 203 int hw_get_module(const char *id, const struct hw_module_t **module); 204 205 /** 206 * Get the module info associated with a module instance by class 'class_id' 207 * and instance 'inst'. 208 * 209 * Some modules types necessitate multiple instances. For example audio supports 210 * multiple concurrent interfaces and thus 'audio' is the module class 211 * and 'primary' or 'a2dp' are module interfaces. This implies that the files 212 * providing these modules would be named audio.primary.<variant>.so and 213 * audio.a2dp.<variant>.so 214 * 215 * @return: 0 == success, <0 == error and *module == NULL 216 */ 217 int hw_get_module_by_class(const char *class_id, const char *inst, 218 const struct hw_module_t **module); 219 220 __END_DECLS 221 222 #endif /* ANDROID_INCLUDE_HARDWARE_HARDWARE_H */ 223