nuttx-apps/examples/fb/fb_main.c

/****************************************************************************
 * examples/fb/fb_main.c
 *
 *   Copyright (C) 2017 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/ioctl.h>
#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>

#include <nuttx/video/fb.h>

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct fb_state_s
{
  int fd;
  struct fb_videoinfo_s vinfo;
  struct fb_planeinfo_s pinfo;
  FAR void *fbmem;
};

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const char g_default_fbdev[] = CONFIG_EXAMPLES_FB_DEFAULTFB;

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * fb_main
 ****************************************************************************/

#ifdef CONFIG_BUILD_KERNEL
int main(int argc, FAR char *argv[])
#else
int fb_main(int argc, char *argv[])
#endif
{
  struct fb_state_s state;
  FAR const char *fbdev = g_default_fbdev;
  int ret;

  /* There is a single required argument:  The path to the framebuffer
   * driver.
   */

  if (argc == 2)
    {
      fbdev = argv[1];
    }
  else if (argc != 1)
    {
      fprintf(stderr, "ERROR: Single argument required\n");
      fprintf(stderr, "USAGE: %s [<fb-driver-path>]\n", argv[0]);
      return EXIT_FAILURE;
    }

  /* Open the framebuffer driver */

  state.fd = open(fbdev, O_RDWR);
  if (state.fd < 0)
    {
      int errcode = errno;
      fprintf(stderr, "ERROR: Failed to open %s: %d\n", fbdev, errcode);
      return EXIT_FAILURE;
    }

  /* Get the characteristics of the framebuffer */

  ret = ioctl(state.fd, FBIOGET_VIDEOINFO,
              (unsigned long)((uintptr_t)&state.vinfo));
  if (ret < 0)
    {
      int errcode = errno;
      fprintf(stderr, "ERROR: ioctl(FBIOGET_VIDEOINFO) failed: %d\n",
              errcode);
      close(state.fd);
      return EXIT_FAILURE;
    }

  printf("VideoInfo:\n");
  printf("      fmt: %u\n", state.vinfo.fmt);
  printf("     xres: %u\n", state.vinfo.xres);
  printf("     yres: %u\n", state.vinfo.yres);
  printf("  nplanes: %u\n", state.vinfo.nplanes);

  ret = ioctl(state.fd, FBIOGET_PLANEINFO,
              (unsigned long)((uintptr_t)&state.pinfo));
  if (ret < 0)
    {
      int errcode = errno;
      fprintf(stderr, "ERROR: ioctl(FBIOGET_PLANEINFO) failed: %d\n",
              errcode);
      close(state.fd);
      return EXIT_FAILURE;
    }

  printf("PlaneInfo (plane 0):\n");
  printf("    fbmem: %p\n", state.pinfo.fbmem);
  printf("    fblen: %lu\n", (unsigned long)state.pinfo.fblen);
  printf("   stride: %u\n", state.pinfo.stride);
  printf("  display: %u\n", state.pinfo.display);
  printf("      bpp: %u\n", state.pinfo.bpp);

  /* mmap() the framebuffer */

  state.fbmem = mmap(NULL, state.pinfo.fblen, PROT_READ|PROT_WRITE,
                     MAP_SHARED|MAP_FILE, state.fd, 0);
  if (state.fbmem == MAP_FAILED)
    {
      int errcode = errno;
      fprintf(stderr, "ERROR: ioctl(FBIOGET_PLANEINFO) failed: %d\n",
              errcode);
      close(state.fd);
      return EXIT_FAILURE;
    }

  printf("Mapped FB: %p\n", state.fbmem);

  munmap(state.fd, state.fbmem);
  close(state.fd);
  return EXIT_SUCCESS;
}