hw_get_moduleと、GRALLOC_HARDWARE_MODULE_IDがある場所は？

どうして3箇所、あるんだろ？

     38 GraphicBufferMapper::GraphicBufferMapper()
     39     : mAllocMod(0)
     40 {
     41     hw_module_t const* module;
     42     int err = hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &module);　＜＝ここ
     43     ALOGE_IF(err, "FATAL: can't find the %s module", GRALLOC_HARDWARE_MODULE_ID);
     44     if (err == 0) {
     45         mAllocMod = (gralloc_module_t const *)module;
     46     }
     47 }

     38 GraphicBufferAllocator::GraphicBufferAllocator()
     39     : mAllocDev(0)
     40 {
     41     hw_module_t const* module;
     42     int err = hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &module);　＜＝ここ
     43     ALOGE_IF(err, "FATAL: can't find the %s module", GRALLOC_HARDWARE_MODULE_ID);
     44     if (err == 0) {
     45         gralloc_open(module, &mAllocDev);
     46     }
     47 }

     75 FramebufferNativeWindow::FramebufferNativeWindow()
     76     : BASE(), fbDev(0), grDev(0), mUpdateOnDemand(false)
     77 {
     78     hw_module_t const* module;
     79     if (hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &module) == 0) {  ＜＝ここ
     80         int stride;
     81         int err;
     82         int i;
     83         err = framebuffer_open(module, &fbDev);
     84         ALOGE_IF(err, "couldn't open framebuffer HAL (%s)", strerror(-err));
     85 
     86         err = gralloc_open(module, &grDev);
     87         ALOGE_IF(err, "couldn't open gralloc HAL (%s)", strerror(-err));
     88 
     89         // bail out if we can't initialize the modules
     90         if (!fbDev || !grDev)
     91             return;
     92 
     93         mUpdateOnDemand = (fbDev->setUpdateRect != 0);
     94 
     95         // initialize the buffer FIFO
     96         if(fbDev->numFramebuffers >= MIN_NUM_FRAME_BUFFERS &&
     97            fbDev->numFramebuffers <= MAX_NUM_FRAME_BUFFERS){
     98             mNumBuffers = fbDev->numFramebuffers;
     99         } else {
    100             mNumBuffers = MIN_NUM_FRAME_BUFFERS;
    101         }
    102         mNumFreeBuffers = mNumBuffers;
    103         mBufferHead = mNumBuffers-1;
    104 
    105         /*
    106          * This does not actually change the framebuffer format. It merely
    107          * fakes this format to surfaceflinger so that when it creates
    108          * framebuffer surfaces it will use this format. It's really a giant
    109          * HACK to allow interworking with buggy gralloc+GPU driver
    110          * implementations. You should *NEVER* need to set this for shipping
    111          * devices.
    112          */
    113 #ifdef FRAMEBUFFER_FORCE_FORMAT
    114         *((uint32_t *)&fbDev->format) = FRAMEBUFFER_FORCE_FORMAT;
    115 #endif
    116 
    117         for (i = 0; i < mNumBuffers; i++)
    118         {
    119                 buffers[i] = new NativeBuffer(
    120                         fbDev->width, fbDev->height, fbDev->format, GRALLOC_USAGE_HW_FB);
    121         }
    122 
    123         for (i = 0; i < mNumBuffers; i++)
    124         {
    125                 err = grDev->alloc(grDev,
    126                         fbDev->width, fbDev->height, fbDev->format,
    127                         GRALLOC_USAGE_HW_FB, &buffers[i]->handle, &buffers[i]->stride);
    128 
    129                 ALOGE_IF(err, "fb buffer %d allocation failed w=%d, h=%d, err=%s",
    130                         i, fbDev->width, fbDev->height, strerror(-err));
    131 
    132                 if (err)
    133                 {
    134                         mNumBuffers = i;
    135                         mNumFreeBuffers = i;
    136                         mBufferHead = mNumBuffers-1;
    137                         break;
    138                 }
    139         }
    140 
    141         const_cast<uint32_t&>(ANativeWindow::flags) = fbDev->flags;
    142         const_cast<float&>(ANativeWindow::xdpi) = fbDev->xdpi;
    143         const_cast<float&>(ANativeWindow::ydpi) = fbDev->ydpi;
    144         const_cast<int&>(ANativeWindow::minSwapInterval) =
    145             fbDev->minSwapInterval;
    146         const_cast<int&>(ANativeWindow::maxSwapInterval) =
    147             fbDev->maxSwapInterval;
    148     } else {
    149         ALOGE("Couldn't get gralloc module");
    150     }
    151 
    152     ANativeWindow::setSwapInterval = setSwapInterval;
    153     ANativeWindow::dequeueBuffer = dequeueBuffer;
    154     ANativeWindow::queueBuffer = queueBuffer;
    155     ANativeWindow::query = query;
    156     ANativeWindow::perform = perform;
    157 
    158     ANativeWindow::dequeueBuffer_DEPRECATED = dequeueBuffer_DEPRECATED;
    159     ANativeWindow::lockBuffer_DEPRECATED = lockBuffer_DEPRECATED;
    160     ANativeWindow::queueBuffer_DEPRECATED = queueBuffer_DEPRECATED;
    161 }

    247 // Load and prepare the FB HAL, which uses the gralloc module.  Sets mFbDev.
    248 void HWComposer::loadFbHalModule()
    249 {
    250     hw_module_t const* module;
    251 
    252     if (hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &module) != 0) {
    253         ALOGE("%s module not found", GRALLOC_HARDWARE_MODULE_ID);
    254         return;
    255     }
    256 
    257     int err = framebuffer_open(module, &mFbDev);
    258     if (err) {
    259         ALOGE("framebuffer_open failed (%s)", strerror(-err));
    260         return;
    261     }
    262 }

   1699 static int omap4_hwc_open_fb_hal(IMG_framebuffer_device_public_t **fb_dev)
   1700 {
   1701     const struct hw_module_t *psModule;
   1702     IMG_gralloc_module_public_t *psGrallocModule;
   1703     int err;
   1704 
   1705     err = hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &psModule);
   1706     psGrallocModule = (IMG_gralloc_module_public_t *) psModule;
   1707 
   1708     if(err)
   1709         goto err_out;
   1710 
   1711     if (strcmp(psGrallocModule->base.common.author, "Imagination Technologies")) {
   1712         err = -EINVAL;
   1713         goto err_out;
   1714     }
   1715 
   1716     *fb_dev = psGrallocModule->psFrameBufferDevice;
   1717 
   1718     return 0;
   1719 
   1720 err_out:
   1721     ALOGE("Composer HAL failed to load compatible Graphics HAL");
   1722     return err;
   1723 }