drivers/video/console/dummycon.c

   1 /*
   2  *  linux/drivers/video/dummycon.c -- A dummy console driver
   3  *
   4  *  To be used if there's no other console driver (e.g. for plain VGA text)
   5  *  available, usually until fbcon takes console over.
   6  */
   7
   8 #include <linux/types.h>
   9 #include <linux/kdev_t.h>
  10 #include <linux/console.h>
  11 #include <linux/vt_kern.h>
  12 #include <linux/screen_info.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15
  16 /*
  17  *  Dummy console driver
  18  */
  19
  20 #if defined(__arm__)
  21 #define DUMMY_COLUMNS   screen_info.orig_video_cols
  22 #define DUMMY_ROWS      screen_info.orig_video_lines
  23 #else
  24 /* set by Kconfig. Use 80x25 for 640x480 and 160x64 for 1280x1024 */
  25 #define DUMMY_COLUMNS   CONFIG_DUMMY_CONSOLE_COLUMNS
  26 #define DUMMY_ROWS      CONFIG_DUMMY_CONSOLE_ROWS
  27 #endif
  28
  29 static const char *dummycon_startup(void)
  30 {
  31     return "dummy device";
  32 }
  33
  34 static void dummycon_init(struct vc_data *vc, int init)
  35 {
  36     vc->vc_can_do_color = 1;
  37     if (init) {
  38         vc->vc_cols = DUMMY_COLUMNS;
  39         vc->vc_rows = DUMMY_ROWS;
  40     } else
  41         vc_resize(vc, DUMMY_COLUMNS, DUMMY_ROWS);
  42 }
  43
  44 static int dummycon_dummy(void)
  45 {
  46     return 0;
  47 }
  48
  49 #define DUMMY   (void *)dummycon_dummy
  50
  51 /*
  52  *  The console `switch' structure for the dummy console
  53  *
  54  *  Most of the operations are dummies.
  55  */
  56
  57 const struct consw dummy_con = {
  58     .owner =            THIS_MODULE,
  59     .con_startup =      dummycon_startup,
  60     .con_init =         dummycon_init,
  61     .con_deinit =       DUMMY,
  62     .con_clear =        DUMMY,
  63     .con_putc =         DUMMY,
  64     .con_putcs =        DUMMY,
  65     .con_cursor =       DUMMY,
  66     .con_scroll =       DUMMY,
  67     .con_switch =       DUMMY,
  68     .con_blank =        DUMMY,
  69     .con_font_set =     DUMMY,
  70     .con_font_default = DUMMY,
  71     .con_font_copy =    DUMMY,
  72 };
  73 EXPORT_SYMBOL_GPL(dummy_con);