Android中hardware源码（android-5.0.2）
16lz
2021-01-23
Android中hardware源码（android-5.0.2）
路径：android-5.0.2/hardware/libhardware/include/hardware/hardware.h
hardware.h
/* * 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 * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */#ifndef ANDROID_INCLUDE_HARDWARE_HARDWARE_H#define ANDROID_INCLUDE_HARDWARE_HARDWARE_H#include #include #include #include __BEGIN_DECLS/* * 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_MODULE_TAG MAKE_TAG_CONSTANT('H', 'W', 'M', 'T')#define HARDWARE_DEVICE_TAG MAKE_TAG_CONSTANT('H', 'W', 'D', 'T')#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))#define HARDWARE_API_VERSION_2_MAJ_MIN_MASK 0xffff0000#define HARDWARE_API_VERSION_2_HEADER_MASK 0x0000ffff/* * 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. * */#define HARDWARE_HAL_API_VERSION HARDWARE_MAKE_API_VERSION(1, 0)/* * 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. */#define HARDWARE_MODULE_API_VERSION(maj,min) HARDWARE_MAKE_API_VERSION(maj,min)#define HARDWARE_MODULE_API_VERSION_2(maj,min,hdr) HARDWARE_MAKE_API_VERSION_2(maj,min,hdr)/* * Use this macro to set the hw_device_t.version field */#define HARDWARE_DEVICE_API_VERSION(maj,min) HARDWARE_MAKE_API_VERSION(maj,min)#define HARDWARE_DEVICE_API_VERSION_2(maj,min,hdr) HARDWARE_MAKE_API_VERSION_2(maj,min,hdr)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;#ifdef __LP64__ uint64_t reserved[32-7];#else /** padding to 128 bytes, reserved for future use */ uint32_t reserved[32-7];#endif} 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 */#ifdef __LP64__ uint64_t reserved[12];#else uint32_t reserved[12];#endif /** Close this device */ int (*close)(struct hw_device_t* device);} hw_device_t;/** * Name of the hal_module_info */#define HAL_MODULE_INFO_SYM HMI/** * Name of the hal_module_info as a string */#define HAL_MODULE_INFO_SYM_AS_STR "HMI"/** * 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..so and * audio.a2dp..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);__END_DECLS#endif /* ANDROID_INCLUDE_HARDWARE_HARDWARE_H */ 路径：android-5.0.2/hardware/libhardware/hardware.c
hardware.c
/* * 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 * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */#include #include #include #include #include #include #include #define LOG_TAG "HAL"#include /** Base path of the hal modules */#if defined(__LP64__)#define HAL_LIBRARY_PATH1 "/system/lib64/hw"#define HAL_LIBRARY_PATH2 "/vendor/lib64/hw"#else#define HAL_LIBRARY_PATH1 "/system/lib/hw"#define HAL_LIBRARY_PATH2 "/vendor/lib/hw"#endif/** * There are a set of variant filename for modules. The form of the filename * is ".variant.so" so for the led module the Dream variants * of base "ro.product.board", "ro.board.platform" and "ro.arch" would be: * * led.trout.so * led.msm7k.so * led.ARMV6.so * led.default.so */static const char *variant_keys[] = { "ro.hardware", /* This goes first so that it can pick up a different file on the emulator. */ "ro.product.board", "ro.board.platform", "ro.arch"};static const int HAL_VARIANT_KEYS_COUNT = (sizeof(variant_keys)/sizeof(variant_keys[0]));/** * Load the file defined by the variant and if successful * return the dlopen handle and the hmi. * @return 0 = success, !0 = failure. */static int load(const char *id, const char *path, const struct hw_module_t **pHmi){ int status; void *handle; struct hw_module_t *hmi; /* * load the symbols resolving undefined symbols before * dlopen returns. Since RTLD_GLOBAL is not or'd in with * RTLD_NOW the external symbols will not be global */ handle = dlopen(path, RTLD_NOW); if (handle == NULL) { char const *err_str = dlerror(); ALOGE("load: module=%s\n%s", path, err_str?err_str:"unknown"); status = -EINVAL; goto done; } /* Get the address of the struct hal_module_info. */ const char *sym = HAL_MODULE_INFO_SYM_AS_STR; hmi = (struct hw_module_t *)dlsym(handle, sym); if (hmi == NULL) { ALOGE("load: couldn't find symbol %s", sym); status = -EINVAL; goto done; } /* Check that the id matches */ if (strcmp(id, hmi->id) != 0) { ALOGE("load: id=%s != hmi->id=%s", id, hmi->id); status = -EINVAL; goto done; } hmi->dso = handle; /* success */ status = 0; done: if (status != 0) { hmi = NULL; if (handle != NULL) { dlclose(handle); handle = NULL; } } else { ALOGV("loaded HAL id=%s path=%s hmi=%p handle=%p", id, path, *pHmi, handle); } *pHmi = hmi; return status;}/* * Check if a HAL with given name and subname exists, if so return 0, otherwise * otherwise return negative. On success path will contain the path to the HAL. */static int hw_module_exists(char *path, size_t path_len, const char *name, const char *subname){ snprintf(path, path_len, "%s/%s.%s.so", HAL_LIBRARY_PATH2, name, subname); if (access(path, R_OK) == 0) return 0; snprintf(path, path_len, "%s/%s.%s.so", HAL_LIBRARY_PATH1, name, subname); if (access(path, R_OK) == 0) return 0; return -ENOENT;}int hw_get_module_by_class(const char *class_id, const char *inst, const struct hw_module_t **module){ int i; char prop[PATH_MAX]; char path[PATH_MAX]; char name[PATH_MAX]; char prop_name[PATH_MAX]; if (inst) snprintf(name, PATH_MAX, "%s.%s", class_id, inst); else strlcpy(name, class_id, PATH_MAX); /* * Here we rely on the fact that calling dlopen multiple times on * the same .so will simply increment a refcount (and not load * a new copy of the library). * We also assume that dlopen() is thread-safe. */ /* First try a property specific to the class and possibly instance */ snprintf(prop_name, sizeof(prop_name), "ro.hardware.%s", name); if (property_get(prop_name, prop, NULL) > 0) { if (hw_module_exists(path, sizeof(path), name, prop) == 0) { goto found; } } /* Loop through the configuration variants looking for a module */ for (i=0 ; i
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