vgacon.c

Linux环境下视频显示卡设备的驱动程序源代码

/*
 *  linux/drivers/video/vgacon.c -- Low level VGA based console driver
 *
 *	Created 28 Sep 1997 by Geert Uytterhoeven
 *
 *	Rewritten by Martin Mares <[e-mail]>, July 1998
 *
 *  This file is based on the old console.c, vga.c and vesa_blank.c drivers.
 *
 *	Copyright (C) 1991, 1992  Linus Torvalds
 *			    1995  Jay Estabrook
 *
 *	User definable mapping table and font loading by Eugene G. Crosser,
 *	<[e-mail]>
 *
 *	Improved loadable font/UTF-8 support by H. Peter Anvin
 *	Feb-Sep 1995 <[e-mail]>
 *
 *	Colour palette handling, by Simon Tatham
 *	17-Jun-95 <[e-mail]>
 *
 *	if 512 char mode is already enabled don't re-enable it,
 *	because it causes screen to flicker, by Mitja Horvat
 *	5-May-96 <[e-mail]>
 *
 *	Use 2 outw instead of 4 outb_p to reduce erroneous text
 *	flashing on RHS of screen during heavy console scrolling .
 *	Oct 1996, Paul Gortmaker.
 *
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License.  See the file COPYING in the main directory of this archive for
 *  more details.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/console.h>
#include <linux/string.h>
#include <linux/kd.h>
#include <linux/slab.h>
#include <linux/vt_kern.h>
#include <linux/selection.h>
#include <linux/spinlock.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/screen_info.h>
#include <linux/smp_lock.h>
#include <video/vga.h>
#include <asm/io.h>

static DEFINE_SPINLOCK(vga_lock);
static int cursor_size_lastfrom;
static int cursor_size_lastto;
static u32 vgacon_xres;
static u32 vgacon_yres;
static struct vgastate state;

#define BLANK 0x0020

#define CAN_LOAD_EGA_FONTS	/* undefine if the user must not do this */
#define CAN_LOAD_PALETTE	/* undefine if the user must not do this */

/* You really do _NOT_ want to define this, unless you have buggy
 * Trident VGA which will resize cursor when moving it between column
 * 15 & 16. If you define this and your VGA is OK, inverse bug will
 * appear.
 */
#undef TRIDENT_GLITCH
#define VGA_FONTWIDTH       8   /* VGA does not support fontwidths != 8 */
/*
 *  Interface used by the world
 */

static const char *vgacon_startup(void);
static void vgacon_init(struct vc_data *c, int init);
static void vgacon_deinit(struct vc_data *c);
static void vgacon_cursor(struct vc_data *c, int mode);
static int vgacon_switch(struct vc_data *c);
static int vgacon_blank(struct vc_data *c, int blank, int mode_switch);
static int vgacon_set_palette(struct vc_data *vc, unsigned char *table);
static int vgacon_scrolldelta(struct vc_data *c, int lines);
static int vgacon_set_origin(struct vc_data *c);
static void vgacon_save_screen(struct vc_data *c);
static int vgacon_scroll(struct vc_data *c, int t, int b, int dir,
			 int lines);
static void vgacon_invert_region(struct vc_data *c, u16 * p, int count);
static unsigned long vgacon_uni_pagedir[2];

/* Description of the hardware situation */
static int		vga_init_done		__read_mostly;
static unsigned long	vga_vram_base		__read_mostly;	/* Base of video memory */
static unsigned long	vga_vram_end		__read_mostly;	/* End of video memory */
static unsigned int	vga_vram_size		__read_mostly;	/* Size of video memory */
static u16		vga_video_port_reg	__read_mostly;	/* Video register select port */
static u16		vga_video_port_val	__read_mostly;	/* Video register value port */
static unsigned int	vga_video_num_columns;			/* Number of text columns */
static unsigned int	vga_video_num_lines;			/* Number of text lines */
static int		vga_can_do_color	__read_mostly;	/* Do we support colors? */
static unsigned int	vga_default_font_height __read_mostly;	/* Height of default screen font */
static unsigned char	vga_video_type		__read_mostly;	/* Card type */
static unsigned char	vga_hardscroll_enabled	__read_mostly;
static unsigned char	vga_hardscroll_user_enable __read_mostly = 1;
static unsigned char	vga_font_is_default = 1;
static int		vga_vesa_blanked;
static int 		vga_palette_blanked;
static int 		vga_is_gfx;
static int 		vga_512_chars;
static int 		vga_video_font_height;
static int 		vga_scan_lines		__read_mostly;
static unsigned int 	vga_rolled_over;

int vgacon_text_mode_force = 0;

bool vgacon_text_force(void)
{
	return vgacon_text_mode_force ? true : false;
}
EXPORT_SYMBOL(vgacon_text_force);

static int __init text_mode(char *str)
{
	vgacon_text_mode_force = 1;
	return 1;
}

/* force text mode - used by kernel modesetting */
__setup("nomodeset", text_mode);

static int __init no_scroll(char *str)
{
	/*
	 * Disabling scrollback is required for the Braillex ib80-piezo
	 * Braille reader made by F.H. Papenmeier (Germany).
	 * Use the "no-scroll" bootflag.
	 */
	vga_hardscroll_user_enable = vga_hardscroll_enabled = 0;
	return 1;
}

__setup("no-scroll", no_scroll);

/*
 * By replacing the four outb_p with two back to back outw, we can reduce
 * the window of opportunity to see text mislocated to the RHS of the
 * console during heavy scrolling activity. However there is the remote
 * possibility that some pre-dinosaur hardware won't like the back to back
 * I/O. Since the Xservers get away with it, we should be able to as well.
 */
static inline void write_vga(unsigned char reg, unsigned int val)
{
	unsigned int v1, v2;
	unsigned long flags;

	/*
	 * ddprintk might set the console position from interrupt
	 * handlers, thus the write has to be IRQ-atomic.
	 */
	spin_lock_irqsave(&vga_lock, flags);

#ifndef SLOW_VGA
	v1 = reg + (val & 0xff00);
	v2 = reg + 1 + ((val << 8) & 0xff00);
	outw(v1, vga_video_port_reg);
	outw(v2, vga_video_port_reg);
#else
	outb_p(reg, vga_video_port_reg);
	outb_p(val >> 8, vga_video_port_val);
	outb_p(reg + 1, vga_video_port_reg);
	outb_p(val & 0xff, vga_video_port_val);
#endif
	spin_unlock_irqrestore(&vga_lock, flags);
}

static inline void vga_set_mem_top(struct vc_data *c)
{
	write_vga(12, (c->vc_visible_origin - vga_vram_base) / 2);
}

#ifdef CONFIG_VGACON_SOFT_SCROLLBACK
#include <linux/bootmem.h>
/* software scrollback */
static void *vgacon_scrollback;
static int vgacon_scrollback_tail;
static int vgacon_scrollback_size;
static int vgacon_scrollback_rows;
static int vgacon_scrollback_cnt;
static int vgacon_scrollback_cur;
static int vgacon_scrollback_save;
static int vgacon_scrollback_restore;

static void vgacon_scrollback_init(int pitch)
{
	int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;

	if (vgacon_scrollback) {
		vgacon_scrollback_cnt  = 0;
		vgacon_scrollback_tail = 0;
		vgacon_scrollback_cur  = 0;
		vgacon_scrollback_rows = rows - 1;
		vgacon_scrollback_size = rows * pitch;
	}
}

/*
 * Called only duing init so call of alloc_bootmen is ok.
 * Marked __init_refok to silence modpost.
 */
static void __init_refok vgacon_scrollback_startup(void)
{
	vgacon_scrollback = alloc_bootmem(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE
					  * 1024);
	vgacon_scrollback_init(vga_video_num_columns * 2);
}

static void vgacon_scrollback_update(struct vc_data *c, int t, int count)
{
	void *p;

	if (!vgacon_scrollback_size || c->vc_num != fg_console)
		return;

	p = (void *) (c->vc_origin + t * c->vc_size_row);

	while (count--) {
		scr_memcpyw(vgacon_scrollback + vgacon_scrollback_tail,
			    p, c->vc_size_row);
		vgacon_scrollback_cnt++;
		p += c->vc_size_row;
		vgacon_scrollback_tail += c->vc_size_row;

		if (vgacon_scrollback_tail >= vgacon_scrollback_size)
			vgacon_scrollback_tail = 0;

		if (vgacon_scrollback_cnt > vgacon_scrollback_rows)
			vgacon_scrollback_cnt = vgacon_scrollback_rows;

		vgacon_scrollback_cur = vgacon_scrollback_cnt;
	}
}

static void vgacon_restore_screen(struct vc_data *c)
{
	vgacon_scrollback_save = 0;

	if (!vga_is_gfx && !vgacon_scrollback_restore) {
		scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf,
			    c->vc_screenbuf_size > vga_vram_size ?
			    vga_vram_size : c->vc_screenbuf_size);
		vgacon_scrollback_restore = 1;
		vgacon_scrollback_cur = vgacon_scrollback_cnt;
	}
}

static int vgacon_scrolldelta(struct vc_data *c, int lines)
{
	int start, end, count, soff;

	if (!lines) {
		c->vc_visible_origin = c->vc_origin;
		vga_set_mem_top(c);
		return 1;
	}

	if (!vgacon_scrollback)
		return 1;

	if (!vgacon_scrollback_save) {
		vgacon_cursor(c, CM_ERASE);
		vgacon_save_screen(c);
		vgacon_scrollback_save = 1;
	}

	vgacon_scrollback_restore = 0;
	start = vgacon_scrollback_cur + lines;
	end = start + abs(lines);

	if (start < 0)
		start = 0;

	if (start > vgacon_scrollback_cnt)
		start = vgacon_scrollback_cnt;

	if (end < 0)
		end = 0;

	if (end > vgacon_scrollback_cnt)
		end = vgacon_scrollback_cnt;

	vgacon_scrollback_cur = start;
	count = end - start;
	soff = vgacon_scrollback_tail - ((vgacon_scrollback_cnt - end) *
					 c->vc_size_row);
	soff -= count * c->vc_size_row;

	if (soff < 0)
		soff += vgacon_scrollback_size;

	count = vgacon_scrollback_cnt - start;

	if (count > c->vc_rows)
		count = c->vc_rows;

	if (count) {
		int copysize;

		int diff = c->vc_rows - count;
		void *d = (void *) c->vc_origin;
		void *s = (void *) c->vc_screenbuf;

		count *= c->vc_size_row;
		/* how much memory to end of buffer left? */
		copysize = min(count, vgacon_scrollback_size - soff);
		scr_memcpyw(d, vgacon_scrollback + soff, copysize);
		d += copysize;
		count -= copysize;

		if (count) {
			scr_memcpyw(d, vgacon_scrollback, count);
			d += count;
		}

		if (diff)
			scr_memcpyw(d, s, diff * c->vc_size_row);
	} else
		vgacon_cursor(c, CM_MOVE);

	return 1;
}
#else
#define vgacon_scrollback_startup(...) do { } while (0)
#define vgacon_scrollback_init(...)    do { } while (0)
#define vgacon_scrollback_update(...)  do { } while (0)

static void vgacon_restore_screen(struct vc_data *c)
{
	if (c->vc_origin != c->vc_visible_origin)
		vgacon_scrolldelta(c, 0);
}

static int vgacon_scrolldelta(struct vc_data *c, int lines)
{
	if (!lines)		/* Turn scrollback off */
		c->vc_visible_origin = c->vc_origin;
	else {
		int margin = c->vc_size_row * 4;
		int ul, we, p, st;

		if (vga_rolled_over >
		    (c->vc_scr_end - vga_vram_base) + margin) {
			ul = c->vc_scr_end - vga_vram_base;
			we = vga_rolled_over + c->vc_size_row;
		} else {
			ul = 0;
			we = vga_vram_size;
		}
		p = (c->vc_visible_origin - vga_vram_base - ul + we) % we +
		    lines * c->vc_size_row;
		st = (c->vc_origin - vga_vram_base - ul + we) % we;
		if (st < 2 * margin)
			margin = 0;
		if (p < margin)
			p = 0;
		if (p > st - margin)
			p = st;
		c->vc_visible_origin = vga_vram_base + (p + ul) % we;
	}
	vga_set_mem_top(c);
	return 1;
}
#endif /* CONFIG_VGACON_SOFT_SCROLLBACK */

static const char *vgacon_startup(void)
{
	const char *display_desc = NULL;
	u16 saved1, saved2;
	volatile u16 *p;

	if (screen_info.orig_video_isVGA == VIDEO_TYPE_VLFB) {
	      no_vga:
#ifdef CONFIG_DUMMY_CONSOLE
		conswitchp = &dummy_con;
		return conswitchp->con_startup();
#else
		return NULL;
#endif
	}

	/* boot_params.screen_info initialized? */
	if ((screen_info.orig_video_mode  == 0) &&
	    (screen_info.orig_video_lines == 0) &&
	    (screen_info.orig_video_cols  == 0))
		goto no_vga;

	/* VGA16 modes are not handled by VGACON */
	if ((screen_info.orig_video_mode == 0x0D) ||	/* 320x200/4 */
	    (screen_info.orig_video_mode == 0x0E) ||	/* 640x200/4 */
	    (screen_info.orig_video_mode == 0x10) ||	/* 640x350/4 */
	    (screen_info.orig_video_mode == 0x12) ||	/* 640x480/4 */
	    (screen_info.orig_video_mode == 0x6A))	/* 800x600/4 (VESA) */
		goto no_vga;

	vga_video_num_lines = screen_info.orig_video_lines;
	vga_video_num_columns = screen_info.orig_video_cols;
	state.vgabase = NULL;

	if (screen_info.orig_video_mode == 7) {
		/* Monochrome display */
		vga_vram_base = 0xb0000;
		vga_video_port_reg = VGA_CRT_IM;
		vga_video_port_val = VGA_CRT_DM;
		if ((screen_info.orig_video_ega_bx & 0xff) != 0x10) {
			static struct resource ega_console_resource =
			    { .name = "ega", .start = 0x3B0, .end = 0x3BF };
			vga_video_type = VIDEO_TYPE_EGAM;
			vga_vram_size = 0x8000;
			display_desc = "EGA+";
			request_resource(&ioport_resource,
					 &ega_console_resource);
		} else {
			static struct resource mda1_console_resource =
			    { .name = "mda", .start = 0x3B0, .end = 0x3BB };
			static struct resource mda2_console_resource =
			    { .name = "mda", .start = 0x3BF, .end = 0x3BF };
			vga_video_type = VIDEO_TYPE_MDA;
			vga_vram_size = 0x2000;
			display_desc = "*MDA";
			request_resource(&ioport_resource,
					 &mda1_console_resource);
			request_resource(&ioport_resource,
					 &mda2_console_resource);
			vga_video_font_height = 14;
		}
	} else {
		/* If not, it is color. */
		vga_can_do_color = 1;
		vga_vram_base = 0xb8000;
		vga_video_port_reg = VGA_CRT_IC;
		vga_video_port_val = VGA_CRT_DC;
		if ((screen_info.orig_video_ega_bx & 0xff) != 0x10) {
			int i;

			vga_vram_size = 0x8000;

			if (!screen_info.orig_video_isVGA) {
				static struct resource ega_console_resource
				    = { .name = "ega", .start = 0x3C0, .end = 0x3DF };
				vga_video_type = VIDEO_TYPE_EGAC;
				display_desc = "EGA";
				request_resource(&ioport_resource,
						 &ega_console_resource);
			} else {
				static struct resource vga_console_resource
				    = { .name = "vga+", .start = 0x3C0, .end = 0x3DF };
				vga_video_type = VIDEO_TYPE_VGAC;
				display_desc = "VGA+";
				request_resource(&ioport_resource,
						 &vga_console_resource);

#ifdef VGA_CAN_DO_64KB
				/*
				 * get 64K rather than 32K of video RAM.
				 * This doesn't actually work on all "VGA"
				 * controllers (it seems like setting MM=01
				 * and COE=1 isn't necessarily a good idea)
				 */
				vga_vram_base = 0xa0000;
				vga_vram_size = 0x10000;
				outb_p(6, VGA_GFX_I);
				outb_p(6, VGA_GFX_D);
#endif
				/*
				 * Normalise the palette registers, to point
				 * the 16 screen colours to the first 16
				 * DAC entries.