linux/fbdev.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include <fcntl.h>
   6 #include <sys/ioctl.h>
   7 #include <sys/mman.h>
   8 #include <unistd.h>
   9 #include <linux/fb.h>
  10 #include <linux/matroxfb.h>
  11
  12 #include "../common/emu.h"
  13 #include "fbdev.h"
  14
  15 #define FBDEV_MAX_BUFFERS 3
  16
  17 static int fbdev = -1;
  18 static void *fbdev_mem = MAP_FAILED;
  19 static int fbdev_mem_size;
  20 static struct fb_var_screeninfo fbvar_old;
  21 static struct fb_var_screeninfo fbvar_new;
  22 static int fbdev_buffer_write;
  23
  24 void *fbdev_buffers[FBDEV_MAX_BUFFERS];
  25 int fbdev_buffer_count;
  26
  27 void plat_video_flip(void)
  28 {
  29         int draw_buf;
  30
  31         if (fbdev_buffer_count < 2)
  32                 return;
  33
  34         draw_buf = fbdev_buffer_write;
  35         fbdev_buffer_write++;
  36         if (fbdev_buffer_write >= fbdev_buffer_count)
  37                 fbdev_buffer_write = 0;
  38
  39         fbvar_new.yoffset = fbvar_old.yres * draw_buf;
  40         g_screen_ptr = fbdev_buffers[fbdev_buffer_write];
  41 }
  42
  43 void plat_video_wait_vsync(void)
  44 {
  45         int arg = 0;
  46         ioctl(fbdev, FBIO_WAITFORVSYNC, &arg);
  47 }
  48
  49 int vout_fbdev_init(int *w, int *h)
  50 {
  51         static const char *fbdev_name = "/dev/fb0";
  52         int i, ret;
  53
  54         fbdev = open(fbdev_name, O_RDWR);
  55         if (fbdev == -1) {
  56                 fprintf(stderr, "%s: ", fbdev_name);
  57                 perror("open");
  58                 return -1;
  59         }
  60
  61         ret = ioctl(fbdev, FBIOGET_VSCREENINFO, &fbvar_old);
  62         if (ret == -1) {
  63                 perror("FBIOGET_VSCREENINFO ioctl");
  64                 goto fail;
  65         }
  66
  67         fbvar_new = fbvar_old;
  68         printf("%s: %ix%i@%d\n", fbdev_name, fbvar_old.xres, fbvar_old.yres, fbvar_old.bits_per_pixel);
  69         *w = fbvar_old.xres;
  70         *h = fbvar_old.yres;
  71         fbdev_buffer_count = FBDEV_MAX_BUFFERS; // be optimistic
  72
  73         if (fbvar_new.bits_per_pixel != 16) {
  74                 printf(" switching to 16bpp\n");
  75                 fbvar_new.bits_per_pixel = 16;
  76                 ret = ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_new);
  77                 if (ret == -1) {
  78                         perror("FBIOPUT_VSCREENINFO ioctl");
  79                         goto fail;
  80                 }
  81         }
  82
  83         if (fbvar_new.yres_virtual < fbvar_old.yres * fbdev_buffer_count) {
  84                 fbvar_new.yres_virtual = fbvar_old.yres * fbdev_buffer_count;
  85                 ret = ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_new);
  86                 if (ret == -1) {
  87                         fbdev_buffer_count = 1;
  88                         fprintf(stderr, "Warning: failed to increase virtual resolution, "
  89                                         "doublebuffering disabled\n");
  90                 }
  91         }
  92
  93         fbdev_mem_size = *w * *h * 2 * fbdev_buffer_count;
  94         fbdev_mem = mmap(0, fbdev_mem_size, PROT_WRITE|PROT_READ, MAP_SHARED, fbdev, 0);
  95         if (fbdev_mem == MAP_FAILED && fbdev_buffer_count > 1) {
  96                 fbdev_mem_size = *w * *h * 2;
  97                 fbdev_buffer_count = 1;
  98                 fprintf(stderr, "Warning: can't map %d bytes, doublebuffering disabled\n", fbdev_mem_size);
  99                 fbdev_mem = mmap(0, fbdev_mem_size, PROT_WRITE|PROT_READ, MAP_SHARED, fbdev, 0);
 100         }
 101         if (fbdev_mem == MAP_FAILED) {
 102                 perror("mmap framebuffer");
 103                 goto fail;
 104         }
 105         memset(fbdev_mem, 0, fbdev_mem_size);
 106         for (i = 0; i < fbdev_buffer_count; i++)
 107                 fbdev_buffers[i] = (char *)fbdev_mem + i * *w * *h * 2;
 108         g_screen_ptr = fbdev_buffers[0];
 109
 110         // some checks
 111         ret = 0;
 112         ret = ioctl(fbdev, FBIO_WAITFORVSYNC, &ret);
 113         if (ret != 0)
 114                 fprintf(stderr, "Warning: vsync doesn't seem to be supported\n");
 115
 116         if (fbdev_buffer_count > 1) {
 117                 fbdev_buffer_write = 0;
 118                 fbvar_new.yoffset = fbvar_old.yres * (fbdev_buffer_count - 1);
 119                 ret = ioctl(fbdev, FBIOPAN_DISPLAY, &fbvar_new);
 120                 if (ret != 0) {
 121                         fbdev_buffer_count = 1;
 122                         fprintf(stderr, "Warning: can't pan display, doublebuffering disabled\n");
 123                 }
 124         }
 125
 126         printf("fbdev initialized.\n");
 127         return 0;
 128
 129 fail:
 130         close(fbdev);
 131         return -1;
 132 }
 133
 134 void vout_fbdev_finish(void)
 135 {
 136         ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_old);
 137         if (fbdev_mem != MAP_FAILED)
 138                 munmap(fbdev_mem, fbdev_mem_size);
 139         if (fbdev >= 0)
 140                 close(fbdev);
 141         fbdev_mem = NULL;
 142         fbdev = -1;
 143 }
 144
 145 #if 0
 146 void *g_screen_ptr;
 147 int main()
 148 {
 149         int w, h;
 150         vout_fbdev_init(&w, &h);
 151         //while (1)
 152         {
 153                 memset(g_screen_ptr, 0xff, fbdev_mem_size / 2);
 154                 plat_video_wait_vsync();
 155                 plat_video_flip();
 156                 memset(g_screen_ptr, 0x00, fbdev_mem_size / 2);
 157                 usleep(8000);
 158 //              plat_video_wait_vsync();
 159                 plat_video_flip();
 160         }
 161 }
 162 #endif