Android中hardware源码（android-5.0.2）

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 <stdint.h>#include <sys/cdefs.h>#include <cutils/native_handle.h>#include <system/graphics.h>__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.<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);__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 <hardware/hardware.h>#include <cutils/properties.h>#include <dlfcn.h>#include <string.h>#include <pthread.h>#include <errno.h>#include <limits.h>#define LOG_TAG "HAL"#include <utils/Log.h>/** 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 "<MODULE_ID>.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<HAL_VARIANT_KEYS_COUNT; i++) {        if (property_get(variant_keys[i], prop, NULL) == 0) {            continue;        }        if (hw_module_exists(path, sizeof(path), name, prop) == 0) {            goto found;        }    }    /* Nothing found, try the default */    if (hw_module_exists(path, sizeof(path), name, "default") == 0) {        goto found;    }    return -ENOENT;found:    /* load the module, if this fails, we're doomed, and we should not try     * to load a different variant. */    return load(class_id, path, module);}int hw_get_module(const char *id, const struct hw_module_t **module){    return hw_get_module_by_class(id, NULL, module);}