vt.c

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/*
 *  linux/drivers/char/vt.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/*
 * Hopefully this will be a rather complete VT102 implementation.
 *
 * Beeping thanks to John T Kohl.
 *
 * Virtual Consoles, Screen Blanking, Screen Dumping, Color, Graphics
 *   Chars, and VT100 enhancements by Peter MacDonald.
 *
 * Copy and paste function by Andrew Haylett,
 *   some enhancements by Alessandro Rubini.
 *
 * Code to check for different video-cards mostly by Galen Hunt,
 * <[e-mail]>
 *
 * Rudimentary ISO 10646/Unicode/UTF-8 character set support by
 * Markus Kuhn, <[e-mail]>.
 *
 * Dynamic allocation of consoles, [e-mail], May 1994
 * Resizing of consoles, aeb, 940926
 *
 * Code for xterm like mouse click reporting by Peter Orbaek 20-Jul-94
 * <[e-mail]>
 *
 * User-defined bell sound, new setterm control sequences and printk
 * redirection by Martin Mares <[e-mail]> 19-Nov-95
 *
 * APM screenblank bug fixed Takashi Manabe <[e-mail]>
 *
 * Merge with the abstract console driver by Geert Uytterhoeven
 * <[e-mail]>, Jan 1997.
 *
 *   Original m68k console driver modifications by
 *
 *     - Arno Griffioen <[e-mail]>
 *     - David Carter <[e-mail]>
 * 
 *   The abstract console driver provides a generic interface for a text
 *   console. It supports VGA text mode, frame buffer based graphical consoles
 *   and special graphics processors that are only accessible through some
 *   registers (e.g. a TMS340x0 GSP).
 *
 *   The interface to the hardware is specified using a special structure
 *   (struct consw) which contains function pointers to console operations
 *   (see <linux/console.h> for more information).
 *
 * Support for changeable cursor shape
 * by Pavel Machek <[e-mail]>, August 1997
 *
 * Ported to i386 and con_scrolldelta fixed
 * by Emmanuel Marty <[e-mail]>, April 1998
 *
 * Resurrected character buffers in videoram plus lots of other trickery
 * by Martin Mares <[e-mail]>, July 1998
 *
 * Removed old-style timers, introduced console_timer, made timer
 * deletion SMP-safe.  17Jun00, Andrew Morton <[e-mail]>
 *
 * Removed console_lock, enabled interrupts across all console operations
 * 13 March 2001, Andrew Morton
 *
 * Fixed UTF-8 mode so alternate charset modes always work according
 * to control sequences interpreted in do_con_trol function
 * preserving backward VT100 semigraphics compatibility,
 * malformed UTF sequences represented as sequences of replacement glyphs,
 * original codes or '?' as a last resort if replacement glyph is undefined
 * by Adam Tla/lka <[e-mail]>, Aug 2006
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/kd.h>
#include <linux/slab.h>
#include <linux/major.h>
#include <linux/mm.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/vt_kern.h>
#include <linux/selection.h>
#include <linux/tiocl.h>
#include <linux/kbd_kern.h>
#include <linux/consolemap.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/bootmem.h>
#include <linux/pm.h>
#include <linux/font.h>
#include <linux/bitops.h>
#include <linux/notifier.h>

#include <asm/io.h>
#include <asm/system.h>
#include <asm/uaccess.h>

#define MAX_NR_CON_DRIVER 16

#define CON_DRIVER_FLAG_MODULE 1
#define CON_DRIVER_FLAG_INIT   2
#define CON_DRIVER_FLAG_ATTR   4

struct con_driver {
	const struct consw *con;
	const char *desc;
	struct device *dev;
	int node;
	int first;
	int last;
	int flag;
};

static struct con_driver registered_con_driver[MAX_NR_CON_DRIVER];
const struct consw *conswitchp;

/* A bitmap for codes <32. A bit of 1 indicates that the code
 * corresponding to that bit number invokes some special action
 * (such as cursor movement) and should not be displayed as a
 * glyph unless the disp_ctrl mode is explicitly enabled.
 */
#define CTRL_ACTION 0x0d00ff81
#define CTRL_ALWAYS 0x0800f501	/* Cannot be overridden by disp_ctrl */

/*
 * Here is the default bell parameters: 750HZ, 1/8th of a second
 */
#define DEFAULT_BELL_PITCH	750
#define DEFAULT_BELL_DURATION	(HZ/8)

struct vc vc_cons [MAX_NR_CONSOLES];

#ifndef VT_SINGLE_DRIVER
static const struct consw *con_driver_map[MAX_NR_CONSOLES];
#endif

static int con_open(struct tty_struct *, struct file *);
static void vc_init(struct vc_data *vc, unsigned int rows,
		    unsigned int cols, int do_clear);
static void gotoxy(struct vc_data *vc, int new_x, int new_y);
static void save_cur(struct vc_data *vc);
static void reset_terminal(struct vc_data *vc, int do_clear);
static void con_flush_chars(struct tty_struct *tty);
static int set_vesa_blanking(char __user *p);
static void set_cursor(struct vc_data *vc);
static void hide_cursor(struct vc_data *vc);
static void console_callback(struct work_struct *ignored);
static void blank_screen_t(unsigned long dummy);
static void set_palette(struct vc_data *vc);

static int printable;		/* Is console ready for printing? */
int default_utf8 = true;
module_param(default_utf8, int, S_IRUGO | S_IWUSR);

/*
 * ignore_poke: don't unblank the screen when things are typed.  This is
 * mainly for the privacy of braille terminal users.
 */
static int ignore_poke;

int do_poke_blanked_console;
int console_blanked;

static int vesa_blank_mode; /* 0:none 1:suspendV 2:suspendH 3:powerdown */
static int blankinterval = 10*60*HZ;
static int vesa_off_interval;

static DECLARE_WORK(console_work, console_callback);

/*
 * fg_console is the current virtual console,
 * last_console is the last used one,
 * want_console is the console we want to switch to,
 * kmsg_redirect is the console for kernel messages,
 */
int fg_console;
int last_console;
int want_console = -1;
int kmsg_redirect;

/*
 * For each existing display, we have a pointer to console currently visible
 * on that display, allowing consoles other than fg_console to be refreshed
 * appropriately. Unless the low-level driver supplies its own display_fg
 * variable, we use this one for the "master display".
 */
static struct vc_data *master_display_fg;

/*
 * Unfortunately, we need to delay tty echo when we're currently writing to the
 * console since the code is (and always was) not re-entrant, so we schedule
 * all flip requests to process context with schedule-task() and run it from
 * console_callback().
 */

/*
 * For the same reason, we defer scrollback to the console callback.
 */
static int scrollback_delta;

/*
 * Hook so that the power management routines can (un)blank
 * the console on our behalf.
 */
int (*console_blank_hook)(int);

static DEFINE_TIMER(console_timer, blank_screen_t, 0, 0);
static int blank_state;
static int blank_timer_expired;
enum {
	blank_off = 0,
	blank_normal_wait,
	blank_vesa_wait,
};

/*
 * Notifier list for console events.
 */
static ATOMIC_NOTIFIER_HEAD(vt_notifier_list);

int register_vt_notifier(struct notifier_block *nb)
{
	return atomic_notifier_chain_register(&vt_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(register_vt_notifier);

int unregister_vt_notifier(struct notifier_block *nb)
{
	return atomic_notifier_chain_unregister(&vt_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(unregister_vt_notifier);

static void notify_write(struct vc_data *vc, unsigned int unicode)
{
	struct vt_notifier_param param = { .vc = vc, unicode = unicode };
	atomic_notifier_call_chain(&vt_notifier_list, VT_WRITE, &param);
}

static void notify_update(struct vc_data *vc)
{
	struct vt_notifier_param param = { .vc = vc };
	atomic_notifier_call_chain(&vt_notifier_list, VT_UPDATE, &param);
}

/*
 *	Low-Level Functions
 */

#define IS_FG(vc)	((vc)->vc_num == fg_console)

#ifdef VT_BUF_VRAM_ONLY
#define DO_UPDATE(vc)	0
#else
#define DO_UPDATE(vc)	CON_IS_VISIBLE(vc)
#endif

static inline unsigned short *screenpos(struct vc_data *vc, int offset, int viewed)
{
	unsigned short *p;
	
	if (!viewed)
		p = (unsigned short *)(vc->vc_origin + offset);
	else if (!vc->vc_sw->con_screen_pos)
		p = (unsigned short *)(vc->vc_visible_origin + offset);
	else
		p = vc->vc_sw->con_screen_pos(vc, offset);
	return p;
}

static inline void scrolldelta(int lines)
{
	scrollback_delta += lines;
	schedule_console_callback();
}

void schedule_console_callback(void)
{
	schedule_work(&console_work);
}

static void scrup(struct vc_data *vc, unsigned int t, unsigned int b, int nr)
{
	unsigned short *d, *s;

	if (t+nr >= b)
		nr = b - t - 1;
	if (b > vc->vc_rows || t >= b || nr < 1)
		return;
	if (CON_IS_VISIBLE(vc) && vc->vc_sw->con_scroll(vc, t, b, SM_UP, nr))
		return;
	d = (unsigned short *)(vc->vc_origin + vc->vc_size_row * t);
	s = (unsigned short *)(vc->vc_origin + vc->vc_size_row * (t + nr));
	scr_memmovew(d, s, (b - t - nr) * vc->vc_size_row);
	scr_memsetw(d + (b - t - nr) * vc->vc_cols, vc->vc_video_erase_char,
		    vc->vc_size_row * nr);
}

static void scrdown(struct vc_data *vc, unsigned int t, unsigned int b, int nr)
{
	unsigned short *s;
	unsigned int step;

	if (t+nr >= b)
		nr = b - t - 1;
	if (b > vc->vc_rows || t >= b || nr < 1)
		return;
	if (CON_IS_VISIBLE(vc) && vc->vc_sw->con_scroll(vc, t, b, SM_DOWN, nr))
		return;
	s = (unsigned short *)(vc->vc_origin + vc->vc_size_row * t);
	step = vc->vc_cols * nr;
	scr_memmovew(s + step, s, (b - t - nr) * vc->vc_size_row);
	scr_memsetw(s, vc->vc_video_erase_char, 2 * step);
}

static void do_update_region(struct vc_data *vc, unsigned long start, int count)
{
#ifndef VT_BUF_VRAM_ONLY
	unsigned int xx, yy, offset;
	u16 *p;

	p = (u16 *) start;
	if (!vc->vc_sw->con_getxy) {
		offset = (start - vc->vc_origin) / 2;
		xx = offset % vc->vc_cols;
		yy = offset / vc->vc_cols;
	} else {
		int nxx, nyy;
		start = vc->vc_sw->con_getxy(vc, start, &nxx, &nyy);
		xx = nxx; yy = nyy;
	}
	for(;;) {
		u16 attrib = scr_readw(p) & 0xff00;
		int startx = xx;
		u16 *q = p;
		while (xx < vc->vc_cols && count) {
			if (attrib != (scr_readw(p) & 0xff00)) {
				if (p > q)
					vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
				startx = xx;
				q = p;
				attrib = scr_readw(p) & 0xff00;
			}
			p++;
			xx++;
			count--;
		}
		if (p > q)
			vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
		if (!count)
			break;
		xx = 0;
		yy++;
		if (vc->vc_sw->con_getxy) {
			p = (u16 *)start;
			start = vc->vc_sw->con_getxy(vc, start, NULL, NULL);
		}
	}
#endif
}

void update_region(struct vc_data *vc, unsigned long start, int count)
{
	WARN_CONSOLE_UNLOCKED();

	if (DO_UPDATE(vc)) {
		hide_cursor(vc);
		do_update_region(vc, start, count);
		set_cursor(vc);
	}
}

/* Structure of attributes is hardware-dependent */

static u8 build_attr(struct vc_data *vc, u8 _color, u8 _intensity, u8 _blink,
    u8 _underline, u8 _reverse, u8 _italic)
{
	if (vc->vc_sw->con_build_attr)
		return vc->vc_sw->con_build_attr(vc, _color, _intensity,
		       _blink, _underline, _reverse, _italic);

#ifndef VT_BUF_VRAM_ONLY
/*
 * ++roman: I completely changed the attribute format for monochrome
 * mode (!can_do_color). The formerly used MDA (monochrome display
 * adapter) format didn't allow the combination of certain effects.
 * Now the attribute is just a bit vector:
 *  Bit 0..1: intensity (0..2)
 *  Bit 2   : underline
 *  Bit 3   : reverse
 *  Bit 7   : blink
 */
	{
	u8 a = vc->vc_color;
	if (!vc->vc_can_do_color)
		return _intensity |
		       (_italic ? 2 : 0) |
		       (_underline ? 4 : 0) |
		       (_reverse ? 8 : 0) |
		       (_blink ? 0x80 : 0);
	if (_italic)
		a = (a & 0xF0) | vc->vc_itcolor;
	else if (_underline)
		a = (a & 0xf0) | vc->vc_ulcolor;
	else if (_intensity == 0)
		a = (a & 0xf0) | vc->vc_ulcolor;
	if (_reverse)
		a = ((a) & 0x88) | ((((a) >> 4) | ((a) << 4)) & 0x77);
	if (_blink)
		a ^= 0x80;
	if (_intensity == 2)
		a ^= 0x08;
	if (vc->vc_hi_font_mask == 0x100)
		a <<= 1;
	return a;
	}
#else
	return 0;
#endif
}

static void update_attr(struct vc_data *vc)
{
	vc->vc_attr = build_attr(vc, vc->vc_color, vc->vc_intensity,
	              vc->vc_blink, vc->vc_underline,
	              vc->vc_reverse ^ vc->vc_decscnm, vc->vc_italic);
	vc->vc_video_erase_char = (build_attr(vc, vc->vc_color, 1, vc->vc_blink, 0, vc->vc_decscnm, 0) << 8) | ' ';
}

/* Note: inverting the screen twice should revert to the original state */
void invert_screen(struct vc_data *vc, int offset, int count, int viewed)
{
	unsigned short *p;

	WARN_CONSOLE_UNLOCKED();

	count /= 2;
	p = screenpos(vc, offset, viewed);
	if (vc->vc_sw->con_invert_region)
		vc->vc_sw->con_invert_region(vc, p, count);
#ifndef VT_BUF_VRAM_ONLY
	else {
		u16 *q = p;
		int cnt = count;
		u16 a;

		if (!vc->vc_can_do_color) {
			while (cnt--) {
			    a = scr_readw(q);
			    a ^= 0x0800;
			    scr_writew(a, q);
			    q++;
			}
		} else if (vc->vc_hi_font_mask == 0x100) {
			while (cnt--) {
				a = scr_readw(q);
				a = ((a) & 0x11ff) | (((a) & 0xe000) >> 4) | (((a) & 0x0e00) << 4);
				scr_writew(a, q);
				q++;
			}
		} else {
			while (cnt--) {
				a = scr_readw(q);
				a = ((a) & 0x88ff) | (((a) & 0x7000) >> 4) | (((a) & 0x0700) << 4);
				scr_writew(a, q);
				q++;
			}
		}
	}
#endif
	if (DO_UPDATE(vc))
		do_update_region(vc, (unsigned long) p, count);
}

/* used by selection: complement pointer position */
void complement_pos(struct vc_data *vc, int offset)
{
	static int old_offset = -1;
	static unsigned short old;
	static unsigned short oldx, oldy;

	WARN_CONSOLE_UNLOCKED();

	if (old_offset != -1 && old_offset >= 0 &&
	    old_offset < vc->vc_screenbuf_size) {
		scr_writew(old, screenpos(vc, old_offset, 1));
		if (DO_UPDATE(vc))
			vc->vc_sw->con_putc(vc, old, oldy, oldx);
	}

	old_offset = offset;

	if (offset != -1 && offset >= 0 &&
	    offset < vc->vc_screenbuf_size) {
		unsigned short new;
		unsigned short *p;
		p = screenpos(vc, offset, 1);
		old = scr_readw(p);
		new = old ^ vc->vc_complement_mask;
		scr_writew(new, p);
		if (DO_UPDATE(vc)) {
			oldx = (offset >> 1) % vc->vc_cols;
			oldy = (offset >> 1) / vc->vc_cols;
			vc->vc_sw->con_putc(vc, new, oldy, oldx);