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_get = DUMMY, 71 .con_font_default = DUMMY, 72 .con_font_copy = DUMMY, 73 }; 74 EXPORT_SYMBOL_GPL(dummy_con); 75