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         ioctl(fbdev, FBIOPAN_DISPLAY, &fbvar_new);
  43 }
  44
  45 void plat_video_wait_vsync(void)
  46 {
  47         int arg = 0;
  48         ioctl(fbdev, FBIO_WAITFORVSYNC, &arg);
  49 }
  50
  51 int vout_fbdev_init(int *w, int *h)
  52 {
  53         static const char *fbdev_name = "/dev/fb0";
  54         int i, ret;
  55
  56         fbdev = open(fbdev_name, O_RDWR);
  57         if (fbdev == -1) {
  58                 fprintf(stderr, "%s: ", fbdev_name);
  59                 perror("open");
  60                 return -1;
  61         }
  62
  63         ret = ioctl(fbdev, FBIOGET_VSCREENINFO, &fbvar_old);
  64         if (ret == -1) {
  65                 perror("FBIOGET_VSCREENINFO ioctl");
  66                 goto fail;
  67         }
  68
  69         fbvar_new = fbvar_old;
  70         printf("%s: %ix%i@%d\n", fbdev_name, fbvar_old.xres, fbvar_old.yres, fbvar_old.bits_per_pixel);
  71         *w = fbvar_old.xres;
  72         *h = fbvar_old.yres;
  73         fbdev_buffer_count = FBDEV_MAX_BUFFERS; // be optimistic
  74
  75         if (fbvar_new.bits_per_pixel != 16) {
  76                 printf(" switching to 16bpp\n");
  77                 fbvar_new.bits_per_pixel = 16;
  78                 ret = ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_new);
  79                 if (ret == -1) {
  80                         perror("FBIOPUT_VSCREENINFO ioctl");
  81                         goto fail;
  82                 }
  83         }
  84
  85         if (fbvar_new.yres_virtual < fbvar_old.yres * fbdev_buffer_count) {
  86                 fbvar_new.yres_virtual = fbvar_old.yres * fbdev_buffer_count;
  87                 ret = ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_new);
  88                 if (ret == -1) {
  89                         fbdev_buffer_count = 1;
  90                         fprintf(stderr, "Warning: failed to increase virtual resolution, "
  91                                         "doublebuffering disabled\n");
  92                 }
  93         }
  94
  95         fbdev_mem_size = *w * *h * 2 * fbdev_buffer_count;
  96         fbdev_mem = mmap(0, fbdev_mem_size, PROT_WRITE|PROT_READ, MAP_SHARED, fbdev, 0);
  97         if (fbdev_mem == MAP_FAILED && fbdev_buffer_count > 1) {
  98                 fprintf(stderr, "Warning: can't map %d bytes, doublebuffering disabled\n", fbdev_mem_size);
  99                 fbdev_mem_size = *w * *h * 2;
 100                 fbdev_buffer_count = 1;
 101                 fbdev_mem = mmap(0, fbdev_mem_size, PROT_WRITE|PROT_READ, MAP_SHARED, fbdev, 0);
 102         }
 103         if (fbdev_mem == MAP_FAILED) {
 104                 perror("mmap framebuffer");
 105                 goto fail;
 106         }
 107         memset(fbdev_mem, 0, fbdev_mem_size);
 108         for (i = 0; i < fbdev_buffer_count; i++)
 109                 fbdev_buffers[i] = (char *)fbdev_mem + i * *w * *h * 2;
 110         g_screen_ptr = fbdev_buffers[0];
 111
 112         // some checks
 113         ret = 0;
 114         ret = ioctl(fbdev, FBIO_WAITFORVSYNC, &ret);
 115         if (ret != 0)
 116                 fprintf(stderr, "Warning: vsync doesn't seem to be supported\n");
 117
 118         if (fbdev_buffer_count > 1) {
 119                 fbdev_buffer_write = 0;
 120                 fbvar_new.yoffset = fbvar_old.yres * (fbdev_buffer_count - 1);
 121                 ret = ioctl(fbdev, FBIOPAN_DISPLAY, &fbvar_new);
 122                 if (ret != 0) {
 123                         fbdev_buffer_count = 1;
 124                         fprintf(stderr, "Warning: can't pan display, doublebuffering disabled\n");
 125                 }
 126         }
 127
 128         printf("fbdev initialized.\n");
 129         return 0;
 130
 131 fail:
 132         close(fbdev);
 133         return -1;
 134 }
 135
 136 void vout_fbdev_finish(void)
 137 {
 138         ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_old);
 139         if (fbdev_mem != MAP_FAILED)
 140                 munmap(fbdev_mem, fbdev_mem_size);
 141         if (fbdev >= 0)
 142                 close(fbdev);
 143         fbdev_mem = NULL;
 144         fbdev = -1;
 145 }
 146
 147 #if 0
 148 void *g_screen_ptr;
 149 int main()
 150 {
 151         int w, h;
 152         vout_fbdev_init(&w, &h);
 153         //while (1)
 154         {
 155                 memset(g_screen_ptr, 0xff, fbdev_mem_size / 2);
 156                 plat_video_wait_vsync();
 157                 plat_video_flip();
 158                 memset(g_screen_ptr, 0x00, fbdev_mem_size / 2);
 159                 usleep(8000);
 160 //              plat_video_wait_vsync();
 161                 plat_video_flip();
 162         }
 163 }
 164 #endif