summaryrefslogtreecommitdiffstats
path: root/drivers/video/console/dummycon.c
blob: 14af5d9e13b00efd153c03f4f4553f52a6a01080 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/drivers/video/dummycon.c -- A dummy console driver
 *
 *  To be used if there's no other console driver (e.g. for plain VGA text)
 *  available, usually until fbcon takes console over.
 */

#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/console.h>
#include <linux/vt_kern.h>
#include <linux/screen_info.h>
#include <linux/init.h>
#include <linux/module.h>

/*
 *  Dummy console driver
 */

#if defined(CONFIG_ARCH_FOOTBRIDGE) && defined(CONFIG_VGA_CONSOLE)
#include <asm/vga.h>
#define DUMMY_COLUMNS	vgacon_screen_info.orig_video_cols
#define DUMMY_ROWS	vgacon_screen_info.orig_video_lines
#else
/* set by Kconfig. Use 80x25 for 640x480 and 160x64 for 1280x1024 */
#define DUMMY_COLUMNS	CONFIG_DUMMY_CONSOLE_COLUMNS
#define DUMMY_ROWS	CONFIG_DUMMY_CONSOLE_ROWS
#endif

#ifdef CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER
/* These are both protected by the console_lock */
static RAW_NOTIFIER_HEAD(dummycon_output_nh);
static bool dummycon_putc_called;

void dummycon_register_output_notifier(struct notifier_block *nb)
{
	WARN_CONSOLE_UNLOCKED();

	raw_notifier_chain_register(&dummycon_output_nh, nb);

	if (dummycon_putc_called)
		nb->notifier_call(nb, 0, NULL);
}

void dummycon_unregister_output_notifier(struct notifier_block *nb)
{
	WARN_CONSOLE_UNLOCKED();

	raw_notifier_chain_unregister(&dummycon_output_nh, nb);
}

static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos)
{
	WARN_CONSOLE_UNLOCKED();

	dummycon_putc_called = true;
	raw_notifier_call_chain(&dummycon_output_nh, 0, NULL);
}

static void dummycon_putcs(struct vc_data *vc, const unsigned short *s,
			   int count, int ypos, int xpos)
{
	int i;

	if (!dummycon_putc_called) {
		/* Ignore erases */
		for (i = 0 ; i < count; i++) {
			if (s[i] != vc->vc_video_erase_char)
				break;
		}
		if (i == count)
			return;

		dummycon_putc_called = true;
	}

	raw_notifier_call_chain(&dummycon_output_nh, 0, NULL);
}

static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
{
	/* Redraw, so that we get putc(s) for output done while blanked */
	return 1;
}
#else
static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos) { }
static void dummycon_putcs(struct vc_data *vc, const unsigned short *s,
			   int count, int ypos, int xpos) { }
static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
{
	return 0;
}
#endif

static const char *dummycon_startup(void)
{
    return "dummy device";
}

static void dummycon_init(struct vc_data *vc, int init)
{
    vc->vc_can_do_color = 1;
    if (init) {
	vc->vc_cols = DUMMY_COLUMNS;
	vc->vc_rows = DUMMY_ROWS;
    } else
	vc_resize(vc, DUMMY_COLUMNS, DUMMY_ROWS);
}

static void dummycon_deinit(struct vc_data *vc) { }
static void dummycon_clear(struct vc_data *vc, int sy, int sx, int height,
			   int width) { }
static void dummycon_cursor(struct vc_data *vc, int mode) { }

static bool dummycon_scroll(struct vc_data *vc, unsigned int top,
			    unsigned int bottom, enum con_scroll dir,
			    unsigned int lines)
{
	return false;
}

static int dummycon_switch(struct vc_data *vc)
{
	return 0;
}

/*
 *  The console `switch' structure for the dummy console
 *
 *  Most of the operations are dummies.
 */

const struct consw dummy_con = {
	.owner =		THIS_MODULE,
	.con_startup =	dummycon_startup,
	.con_init =		dummycon_init,
	.con_deinit =	dummycon_deinit,
	.con_clear =	dummycon_clear,
	.con_putc =		dummycon_putc,
	.con_putcs =	dummycon_putcs,
	.con_cursor =	dummycon_cursor,
	.con_scroll =	dummycon_scroll,
	.con_switch =	dummycon_switch,
	.con_blank =	dummycon_blank,
};
EXPORT_SYMBOL_GPL(dummy_con);