loader/host_fb.c

   1 /* copy-paste from PD */
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <sys/types.h>
   5 #include <sys/stat.h>
   6 #include <fcntl.h>
   7 #include <sys/ioctl.h>
   8 #include <sys/mman.h>
   9 #include <unistd.h>
  10 #include <linux/fb.h>
  11 #include <linux/matroxfb.h>
  12
  13 #define FBDEV_MAX_BUFFERS 3
  14
  15 static int fbdev = -1;
  16 static void *fbdev_mem = MAP_FAILED;
  17 static int fbdev_mem_size;
  18 static struct fb_var_screeninfo fbvar_old;
  19 static struct fb_var_screeninfo fbvar_new;
  20 static int fbdev_buffer_write;
  21
  22 static void *fbdev_buffers[FBDEV_MAX_BUFFERS];
  23 static int fbdev_buffer_count;
  24 static void *g_screen_ptr;
  25
  26 void plat_video_flip(void)
  27 {
  28         int draw_buf;
  29
  30         if (fbdev_buffer_count < 2)
  31                 return;
  32
  33         draw_buf = fbdev_buffer_write;
  34         fbdev_buffer_write++;
  35         if (fbdev_buffer_write >= fbdev_buffer_count)
  36                 fbdev_buffer_write = 0;
  37
  38         fbvar_new.yoffset = fbvar_old.yres * draw_buf;
  39         g_screen_ptr = fbdev_buffers[fbdev_buffer_write];
  40
  41         ioctl(fbdev, FBIOPAN_DISPLAY, &fbvar_new);
  42 }
  43
  44 void plat_video_wait_vsync(void)
  45 {
  46         int arg = 0;
  47         ioctl(fbdev, FBIO_WAITFORVSYNC, &arg);
  48 }
  49
  50 int vout_fbdev_init(int *w, int *h)
  51 {
  52         static const char *fbdev_name = "/dev/fb0";
  53         int i, ret;
  54
  55         fbdev = open(fbdev_name, O_RDWR);
  56         if (fbdev == -1) {
  57                 fprintf(stderr, "%s: ", fbdev_name);
  58                 perror("open");
  59                 return -1;
  60         }
  61
  62         ret = ioctl(fbdev, FBIOGET_VSCREENINFO, &fbvar_old);
  63         if (ret == -1) {
  64                 perror("FBIOGET_VSCREENINFO ioctl");
  65                 goto fail;
  66         }
  67
  68         fbvar_new = fbvar_old;
  69         printf("%s: %ix%i@%d\n", fbdev_name, fbvar_old.xres, fbvar_old.yres, fbvar_old.bits_per_pixel);
  70         *w = fbvar_old.xres;
  71         *h = fbvar_old.yres;
  72         fbdev_buffer_count = FBDEV_MAX_BUFFERS; // be optimistic
  73
  74         if (fbvar_new.bits_per_pixel != 16) {
  75                 printf(" switching to 16bpp\n");
  76                 fbvar_new.bits_per_pixel = 16;
  77                 ret = ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_new);
  78                 if (ret == -1) {
  79                         perror("FBIOPUT_VSCREENINFO ioctl");
  80                         goto fail;
  81                 }
  82         }
  83
  84         if (fbvar_new.yres_virtual < fbvar_old.yres * fbdev_buffer_count) {
  85                 fbvar_new.yres_virtual = fbvar_old.yres * fbdev_buffer_count;
  86                 ret = ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_new);
  87                 if (ret == -1) {
  88                         fbdev_buffer_count = 1;
  89                         fprintf(stderr, "Warning: failed to increase virtual resolution, "
  90                                         "doublebuffering disabled\n");
  91                 }
  92         }
  93
  94         fbdev_mem_size = *w * *h * 2 * fbdev_buffer_count;
  95         fbdev_mem = mmap(0, fbdev_mem_size, PROT_WRITE|PROT_READ, MAP_SHARED, fbdev, 0);
  96         if (fbdev_mem == MAP_FAILED && fbdev_buffer_count > 1) {
  97                 fbdev_mem_size = *w * *h * 2;
  98                 fbdev_buffer_count = 1;
  99                 fprintf(stderr, "Warning: can't map %d bytes, doublebuffering disabled\n", fbdev_mem_size);
 100                 fbdev_mem = mmap(0, fbdev_mem_size, PROT_WRITE|PROT_READ, MAP_SHARED, fbdev, 0);
 101         }
 102         if (fbdev_mem == MAP_FAILED) {
 103                 perror("mmap framebuffer");
 104                 goto fail;
 105         }
 106         memset(fbdev_mem, 0, fbdev_mem_size);
 107         for (i = 0; i < fbdev_buffer_count; i++)
 108                 fbdev_buffers[i] = (char *)fbdev_mem + i * *w * *h * 2;
 109         g_screen_ptr = fbdev_buffers[0];
 110
 111         // some checks
 112         ret = 0;
 113         ret = ioctl(fbdev, FBIO_WAITFORVSYNC, &ret);
 114         if (ret != 0)
 115                 fprintf(stderr, "Warning: vsync doesn't seem to be supported\n");
 116
 117         if (fbdev_buffer_count > 1) {
 118                 fbdev_buffer_write = 0;
 119                 fbvar_new.yoffset = fbvar_old.yres * (fbdev_buffer_count - 1);
 120                 ret = ioctl(fbdev, FBIOPAN_DISPLAY, &fbvar_new);
 121                 if (ret != 0) {
 122                         fbdev_buffer_count = 1;
 123                         fprintf(stderr, "Warning: can't pan display, doublebuffering disabled\n");
 124                 }
 125         }
 126
 127         printf("fbdev initialized.\n");
 128         return 0;
 129
 130 fail:
 131         close(fbdev);
 132         return -1;
 133 }
 134
 135 void vout_fbdev_finish(void)
 136 {
 137         ioctl(fbdev, FBIOPUT_VSCREENINFO, &fbvar_old);
 138         if (fbdev_mem != MAP_FAILED)
 139                 munmap(fbdev_mem, fbdev_mem_size);
 140         if (fbdev >= 0)
 141                 close(fbdev);
 142         fbdev_mem = NULL;
 143         fbdev = -1;
 144 }
 145
 146 #include "header.h"
 147
 148 void *host_video_init(int *stride)
 149 {
 150         int ret, w, h;
 151
 152         ret = vout_fbdev_init(&w, &h);
 153         if (ret != 0)
 154                 return NULL;
 155
 156         *stride = w * 2;
 157         return g_screen_ptr;
 158 }
 159
 160 void *host_video_flip(void)
 161 {
 162         plat_video_flip();
 163         return g_screen_ptr;
 164 }