tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#ifdef CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER
30/* These are both protected by the console_lock */
31static RAW_NOTIFIER_HEAD(dummycon_output_nh);
32static bool dummycon_putc_called;
33
34void dummycon_register_output_notifier(struct notifier_block *nb)
35{
36 raw_notifier_chain_register(&dummycon_output_nh, nb);
37
38 if (dummycon_putc_called)
39 nb->notifier_call(nb, 0, NULL);
40}
41
42void dummycon_unregister_output_notifier(struct notifier_block *nb)
43{
44 raw_notifier_chain_unregister(&dummycon_output_nh, nb);
45}
46
47static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos)
48{
49 dummycon_putc_called = true;
50 raw_notifier_call_chain(&dummycon_output_nh, 0, NULL);
51}
52
53static void dummycon_putcs(struct vc_data *vc, const unsigned short *s,
54 int count, int ypos, int xpos)
55{
56 int i;
57
58 if (!dummycon_putc_called) {
59 /* Ignore erases */
60 for (i = 0 ; i < count; i++) {
61 if (s[i] != vc->vc_video_erase_char)
62 break;
63 }
64 if (i == count)
65 return;
66
67 dummycon_putc_called = true;
68 }
69
70 raw_notifier_call_chain(&dummycon_output_nh, 0, NULL);
71}
72
73static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
74{
75 /* Redraw, so that we get putc(s) for output done while blanked */
76 return 1;
77}
78#else
79static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos) { }
80static void dummycon_putcs(struct vc_data *vc, const unsigned short *s,
81 int count, int ypos, int xpos) { }
82static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
83{
84 return 0;
85}
86#endif
87
88static const char *dummycon_startup(void)
89{
90 return "dummy device";
91}
92
93static void dummycon_init(struct vc_data *vc, int init)
94{
95 vc->vc_can_do_color = 1;
96 if (init) {
97 vc->vc_cols = DUMMY_COLUMNS;
98 vc->vc_rows = DUMMY_ROWS;
99 } else
100 vc_resize(vc, DUMMY_COLUMNS, DUMMY_ROWS);
101}
102
103static void dummycon_deinit(struct vc_data *vc) { }
104static void dummycon_clear(struct vc_data *vc, int sy, int sx, int height,
105 int width) { }
106static void dummycon_cursor(struct vc_data *vc, int mode) { }
107
108static bool dummycon_scroll(struct vc_data *vc, unsigned int top,
109 unsigned int bottom, enum con_scroll dir,
110 unsigned int lines)
111{
112 return false;
113}
114
115static int dummycon_switch(struct vc_data *vc)
116{
117 return 0;
118}
119
120static int dummycon_font_set(struct vc_data *vc, struct console_font *font,
121 unsigned int flags)
122{
123 return 0;
124}
125
126static int dummycon_font_default(struct vc_data *vc,
127 struct console_font *font, char *name)
128{
129 return 0;
130}
131
132static int dummycon_font_copy(struct vc_data *vc, int con)
133{
134 return 0;
135}
136
137/*
138 * The console `switch' structure for the dummy console
139 *
140 * Most of the operations are dummies.
141 */
142
143const struct consw dummy_con = {
144 .owner = THIS_MODULE,
145 .con_startup = dummycon_startup,
146 .con_init = dummycon_init,
147 .con_deinit = dummycon_deinit,
148 .con_clear = dummycon_clear,
149 .con_putc = dummycon_putc,
150 .con_putcs = dummycon_putcs,
151 .con_cursor = dummycon_cursor,
152 .con_scroll = dummycon_scroll,
153 .con_switch = dummycon_switch,
154 .con_blank = dummycon_blank,
155 .con_font_set = dummycon_font_set,
156 .con_font_default = dummycon_font_default,
157 .con_font_copy = dummycon_font_copy,
158};
159EXPORT_SYMBOL_GPL(dummy_con);