src/egl/main/egldriver.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2008 VMware, Inc.
   4  * Copyright 2009-2010 Chia-I Wu <olvaffe@gmail.com>
   5  * Copyright 2010-2011 LunarG, Inc.
   6  * All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the
  10  * "Software"), to deal in the Software without restriction, including
  11  * without limitation the rights to use, copy, modify, merge, publish,
  12  * distribute, sub license, and/or sell copies of the Software, and to
  13  * permit persons to whom the Software is furnished to do so, subject to
  14  * the following conditions:
  15  *
  16  * The above copyright notice and this permission notice (including the
  17  * next paragraph) shall be included in all copies or substantial portions
  18  * of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  25  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  26  * DEALINGS IN THE SOFTWARE.
  27  *
  28  **************************************************************************/
  29
  30
  31 /**
  32  * Functions for choosing and opening/loading device drivers.
  33  */
  34
  35
  36 #include <assert.h>
  37 #include <string.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include "c11/threads.h"
  41
  42 #include "egldefines.h"
  43 #include "egldisplay.h"
  44 #include "egldriver.h"
  45 #include "egllog.h"
  46
  47 #include "util/debug.h"
  48
  49 static mtx_t _eglModuleMutex = _MTX_INITIALIZER_NP;
  50 static _EGLDriver *_eglDriver;
  51
  52 static _EGLDriver *
  53 _eglGetDriver(void)
  54 {
  55    mtx_lock(&_eglModuleMutex);
  56
  57    if (!_eglDriver) {
  58       _eglDriver = calloc(1, sizeof(*_eglDriver));
  59       if (!_eglDriver)
  60          return NULL;
  61       _eglInitDriver(_eglDriver);
  62    }
  63
  64    mtx_unlock(&_eglModuleMutex);
  65
  66    return _eglDriver;
  67 }
  68
  69 static _EGLDriver *
  70 _eglMatchAndInitialize(_EGLDisplay *disp)
  71 {
  72    if (_eglGetDriver())
  73       if (_eglDriver->API.Initialize(_eglDriver, disp))
  74          return _eglDriver;
  75
  76    return NULL;
  77 }
  78
  79 /**
  80  * Match a display to a driver.  The matching is done by finding the first
  81  * driver that can initialize the display.
  82  */
  83 _EGLDriver *
  84 _eglMatchDriver(_EGLDisplay *disp)
  85 {
  86    _EGLDriver *best_drv;
  87
  88    assert(!disp->Initialized);
  89
  90    /* set options */
  91    disp->Options.ForceSoftware =
  92       env_var_as_boolean("LIBGL_ALWAYS_SOFTWARE", false);
  93
  94    best_drv = _eglMatchAndInitialize(disp);
  95    if (!best_drv && !disp->Options.ForceSoftware) {
  96       disp->Options.ForceSoftware = EGL_TRUE;
  97       best_drv = _eglMatchAndInitialize(disp);
  98    }
  99
 100    if (best_drv) {
 101       disp->Driver = best_drv;
 102       disp->Initialized = EGL_TRUE;
 103    }
 104
 105    return best_drv;
 106 }
 107
 108 __eglMustCastToProperFunctionPointerType
 109 _eglGetDriverProc(const char *procname)
 110 {
 111    if (_eglGetDriver() && _eglDriver->API.GetProcAddress)
 112       return _eglDriver->API.GetProcAddress(_eglDriver, procname);
 113
 114    return NULL;
 115 }
 116
 117 /**
 118  * Unload all drivers.
 119  */
 120 void
 121 _eglUnloadDrivers(void)
 122 {
 123    /* this is called at atexit time */
 124    free(_eglDriver);
 125    _eglDriver = NULL;
 126 }