vgacon.c

S3C44B0X下的LCD （framebuffer）驱动资料与相关代码

/*
 *  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/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/tty.h>
#include <linux/console.h>
#include <linux/console_struct.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 <asm/io.h>

static spinlock_t vga_lock = SPIN_LOCK_UNLOCKED;

#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 dac_reg		0x3c8
#define dac_val		0x3c9
#define attrib_port	0x3c0
#define seq_port_reg	0x3c4
#define seq_port_val	0x3c5
#define gr_port_reg	0x3ce
#define gr_port_val	0x3cf
#define video_misc_rd	0x3cc
#define video_misc_wr	0x3c2

/*
 *  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);
static int vgacon_font_op(struct vc_data *c, struct console_font_op *op);
static int vgacon_set_palette(struct vc_data *c, 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 u8 vgacon_build_attr(struct vc_data *c, u8 color, u8 intensity, u8 blink, u8 underline, u8 reverse);
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 unsigned long   vga_vram_base;		/* Base of video memory */
static unsigned long   vga_vram_end;		/* End of video memory */
static u16             vga_video_port_reg;	/* Video register select port */
static u16             vga_video_port_val;	/* 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 = 0;	/* Do we support colors? */
static unsigned int    vga_default_font_height;	/* Height of default screen font */
static unsigned char   vga_video_type;		/* Card type */
static unsigned char   vga_hardscroll_enabled;
static unsigned char   vga_hardscroll_user_enable = 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 unsigned int    vga_rolled_over = 0;


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

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


	vga_video_num_lines = ORIG_VIDEO_LINES;
	vga_video_num_columns = ORIG_VIDEO_COLS;

	if (ORIG_VIDEO_MODE == 7)	/* Is this a monochrome display? */
	{
		vga_vram_base = 0xb0000;
		vga_video_port_reg = 0x3b4;
		vga_video_port_val = 0x3b5;
		if ((ORIG_VIDEO_EGA_BX & 0xff) != 0x10)
		{
			static struct resource ega_console_resource = { "ega", 0x3B0, 0x3BF };
			vga_video_type = VIDEO_TYPE_EGAM;
			vga_vram_end = 0xb8000;
			display_desc = "EGA+";
			request_resource(&ioport_resource, &ega_console_resource);
		}
		else
		{
			static struct resource mda1_console_resource = { "mda", 0x3B0, 0x3BB };
			static struct resource mda2_console_resource = { "mda", 0x3BF, 0x3BF };
			vga_video_type = VIDEO_TYPE_MDA;
			vga_vram_end = 0xb2000;
			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 = 0x3d4;
		vga_video_port_val = 0x3d5;
		if ((ORIG_VIDEO_EGA_BX & 0xff) != 0x10)
		{
			int i;

			vga_vram_end = 0xc0000;

			if (!ORIG_VIDEO_ISVGA) {
				static struct resource ega_console_resource = { "ega", 0x3C0, 0x3DF };
				vga_video_type = VIDEO_TYPE_EGAC;
				display_desc = "EGA";
				request_resource(&ioport_resource, &ega_console_resource);
			} else {
				static struct resource vga_console_resource = { "vga+", 0x3C0, 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_end = 0xb0000;
				outb_p (6, 0x3ce) ;
				outb_p (6, 0x3cf) ;
#endif

				/*
				 * Normalise the palette registers, to point
				 * the 16 screen colours to the first 16
				 * DAC entries.
				 */

				for (i=0; i<16; i++) {
					inb_p (0x3da) ;
					outb_p (i, 0x3c0) ;
					outb_p (i, 0x3c0) ;
				}
				outb_p (0x20, 0x3c0) ;

				/* now set the DAC registers back to their
				 * default values */

				for (i=0; i<16; i++) {
					outb_p (color_table[i], 0x3c8) ;
					outb_p (default_red[i], 0x3c9) ;
					outb_p (default_grn[i], 0x3c9) ;
					outb_p (default_blu[i], 0x3c9) ;
				}
			}
		}
		else
		{
			static struct resource cga_console_resource = { "cga", 0x3D4, 0x3D5 };
			vga_video_type = VIDEO_TYPE_CGA;
			vga_vram_end = 0xba000;
			display_desc = "*CGA";
			request_resource(&ioport_resource, &cga_console_resource);
			vga_video_font_height = 8;
		}
	}

	vga_vram_base = VGA_MAP_MEM(vga_vram_base);
	vga_vram_end = VGA_MAP_MEM(vga_vram_end);

	/*
	 *	Find out if there is a graphics card present.
	 *	Are there smarter methods around?
	 */
	p = (volatile u16 *)vga_vram_base;
	saved1 = scr_readw(p);
	saved2 = scr_readw(p + 1);
	scr_writew(0xAA55, p);
	scr_writew(0x55AA, p + 1);
	if (scr_readw(p) != 0xAA55 || scr_readw(p + 1) != 0x55AA) {
		scr_writew(saved1, p);
		scr_writew(saved2, p + 1);
		goto no_vga;
	}
	scr_writew(0x55AA, p);
	scr_writew(0xAA55, p + 1);
	if (scr_readw(p) != 0x55AA || scr_readw(p + 1) != 0xAA55) {
		scr_writew(saved1, p);
		scr_writew(saved2, p + 1);
		goto no_vga;
	}
	scr_writew(saved1, p);
	scr_writew(saved2, p + 1);

	if (vga_video_type == VIDEO_TYPE_EGAC
	    || vga_video_type == VIDEO_TYPE_VGAC
	    || vga_video_type == VIDEO_TYPE_EGAM) {
		vga_hardscroll_enabled = vga_hardscroll_user_enable;
		vga_default_font_height = ORIG_VIDEO_POINTS;
		vga_video_font_height = ORIG_VIDEO_POINTS;
		/* This may be suboptimal but is a safe bet - go with it */
		video_scan_lines =
			vga_video_font_height * vga_video_num_lines;
	}
	video_font_height = vga_video_font_height;

	return display_desc;
}

static void vgacon_init(struct vc_data *c, int init)
{
	unsigned long p;
	
	/* We cannot be loaded as a module, therefore init is always 1 */
	c->vc_can_do_color = vga_can_do_color;
	c->vc_cols = vga_video_num_columns;
	c->vc_rows = vga_video_num_lines;
	c->vc_complement_mask = 0x7700;
	p = *c->vc_uni_pagedir_loc;
	if (c->vc_uni_pagedir_loc == &c->vc_uni_pagedir ||
	    !--c->vc_uni_pagedir_loc[1])
		con_free_unimap(c->vc_num);
	c->vc_uni_pagedir_loc = vgacon_uni_pagedir;
	vgacon_uni_pagedir[1]++;
	if (!vgacon_uni_pagedir[0] && p)
		con_set_default_unimap(c->vc_num);
}

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

static void vgacon_deinit(struct vc_data *c)
{
	/* When closing the last console, reset video origin */
	if (!--vgacon_uni_pagedir[1]) {