/*
 *  linux/drivers/video/mdacon.c -- Low level MDA based console driver
 *
 *      (c) 1998 Andrew Apted <ajapted@netspace.net.au>
 *
 *      including portions (c) 1995-1998 Patrick Caulfield.
 *
 *      slight improvements (c) 2000 Edward Betts <edward@debian.org>
 *
 *  This file is based on the VGA console driver (vgacon.c):
 *      
 *      Created 28 Sep 1997 by Geert Uytterhoeven
 *
 *      Rewritten by Martin Mares <mj@ucw.cz>, July 1998
 *
 *  and on the old console.c, vga.c and vesa_blank.c drivers:
 *
 *      Copyright (C) 1991, 1992  Linus Torvalds
 *                          1995  Jay Estabrook
 *
 *  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.
 *
 *  Changelog:
 *  Paul G. (03/2001) Fix mdacon= boot prompt to use __setup().
 */

#include <linux/types.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/string.h>
#include <linux/kd.h>
#include <linux/vt_kern.h>
#include <linux/vt_buffer.h>
#include <linux/selection.h>
#include <linux/spinlock.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/init.h>

#include <asm/io.h>
#include <asm/vga.h>

static DEFINE_SPINLOCK(mda_lock);

/* description of the hardware layout */

static u16              *mda_vram_base;         /* Base of video memory */
static unsigned long    mda_vram_len;           /* Size of video memory */
static unsigned int     mda_num_columns;        /* Number of text columns */
static unsigned int     mda_num_lines;          /* Number of text lines */

static unsigned int     mda_index_port;         /* Register select port */
static unsigned int     mda_value_port;         /* Register value port */
static unsigned int     mda_mode_port;          /* Mode control port */
static unsigned int     mda_status_port;        /* Status and Config port */
static unsigned int     mda_gfx_port;           /* Graphics control port */

/* current hardware state */

static int      mda_cursor_loc=-1;
static int      mda_cursor_size_from=-1;
static int      mda_cursor_size_to=-1;

static enum { TYPE_MDA, TYPE_HERC, TYPE_HERCPLUS, TYPE_HERCCOLOR } mda_type;
static char *mda_type_name;

/* console information */

static int      mda_first_vc = 13;
static int      mda_last_vc  = 16;

static struct vc_data   *mda_display_fg = NULL;

module_param(mda_first_vc, int, 0);
MODULE_PARM_DESC(mda_first_vc, "First virtual console. Default: 13");
module_param(mda_last_vc, int, 0);
MODULE_PARM_DESC(mda_last_vc, "Last virtual console. Default: 16");

/* MDA register values
 */

#define MDA_CURSOR_BLINKING     0x00
#define MDA_CURSOR_OFF          0x20
#define MDA_CURSOR_SLOWBLINK    0x60

#define MDA_MODE_GRAPHICS       0x02
#define MDA_MODE_VIDEO_EN       0x08
#define MDA_MODE_BLINK_EN       0x20
#define MDA_MODE_GFX_PAGE1      0x80

#define MDA_STATUS_HSYNC        0x01
#define MDA_STATUS_VSYNC        0x80
#define MDA_STATUS_VIDEO        0x08

#define MDA_CONFIG_COL132       0x08
#define MDA_GFX_MODE_EN         0x01
#define MDA_GFX_PAGE_EN         0x02


/*
 * MDA could easily be classified as "pre-dinosaur hardware".
 */

static void write_mda_b(unsigned int val, unsigned char reg)
{
        unsigned long flags;

        spin_lock_irqsave(&mda_lock, flags);    

        outb_p(reg, mda_index_port); 
        outb_p(val, mda_value_port);

        spin_unlock_irqrestore(&mda_lock, flags);
}

static void write_mda_w(unsigned int val, unsigned char reg)
{
        unsigned long flags;

        spin_lock_irqsave(&mda_lock, flags);

        outb_p(reg,   mda_index_port); outb_p(val >> 8,   mda_value_port);
        outb_p(reg+1, mda_index_port); outb_p(val & 0xff, mda_value_port);

        spin_unlock_irqrestore(&mda_lock, flags);
}

#ifdef TEST_MDA_B
static int test_mda_b(unsigned char val, unsigned char reg)
{
        unsigned long flags;

        spin_lock_irqsave(&mda_lock, flags);

        outb_p(reg, mda_index_port); 
        outb  (val, mda_value_port);

        udelay(20); val = (inb_p(mda_value_port) == val);

        spin_unlock_irqrestore(&mda_lock, flags);
        return val;
}
#endif

static inline void mda_set_cursor(unsigned int location) 
{
        if (mda_cursor_loc == location)
                return;

        write_mda_w(location >> 1, 0x0e);

        mda_cursor_loc = location;
}

static inline void mda_set_cursor_size(int from, int to)
{
        if (mda_cursor_size_from==from && mda_cursor_size_to==to)
                return;
        
        if (from > to) {
                write_mda_b(MDA_CURSOR_OFF, 0x0a);      /* disable cursor */
        } else {
                write_mda_b(from, 0x0a);        /* cursor start */
                write_mda_b(to,   0x0b);        /* cursor end */
        }

        mda_cursor_size_from = from;
        mda_cursor_size_to   = to;
}


#ifndef MODULE
static int __init mdacon_setup(char *str)
{
        /* command line format: mdacon=<first>,<last> */

        int ints[3];

        str = get_options(str, ARRAY_SIZE(ints), ints);

        if (ints[0] < 2)
                return 0;

        if (ints[1] < 1 || ints[1] > MAX_NR_CONSOLES || 
            ints[2] < 1 || ints[2] > MAX_NR_CONSOLES)
                return 0;

        mda_first_vc = ints[1];
        mda_last_vc  = ints[2];
        return 1;
}

__setup("mdacon=", mdacon_setup);
#endif

static int mda_detect(void)
{
        int count=0;
        u16 *p, p_save;
        u16 *q, q_save;

        /* do a memory check */

        p = mda_vram_base;
        q = mda_vram_base + 0x01000 / 2;

        p_save = scr_readw(p);
        q_save = scr_readw(q);

        scr_writew(0xAA55, p);
        if (scr_readw(p) == 0xAA55)
                count++;

        scr_writew(0x55AA, p);
        if (scr_readw(p) == 0x55AA)
                count++;

        scr_writew(p_save, p);

        if (count != 2) {
                return 0;
        }

        /* check if we have 4K or 8K */

        scr_writew(0xA55A, q);
        scr_writew(0x0000, p);
        if (scr_readw(q) == 0xA55A)
                count++;
        
        scr_writew(0x5AA5, q);
        scr_writew(0x0000, p);
        if (scr_readw(q) == 0x5AA5)
                count++;

        scr_writew(p_save, p);
        scr_writew(q_save, q);
        
        if (count == 4) {
                mda_vram_len = 0x02000;
        }
        
        /* Ok, there is definitely a card registering at the correct
         * memory location, so now we do an I/O port test.
         */

#ifdef TEST_MDA_B
        /* Edward: These two mess `tests' mess up my cursor on bootup */

        /* cursor low register */
        if (!test_mda_b(0x66, 0x0f))
                return 0;

        /* cursor low register */
        if (!test_mda_b(0x99, 0x0f))
                return 0;
#endif

        /* See if the card is a Hercules, by checking whether the vsync
         * bit of the status register is changing.  This test lasts for
         * approximately 1/10th of a second.
         */
        
        p_save = q_save = inb_p(mda_status_port) & MDA_STATUS_VSYNC;

        for (count = 0; count < 50000 && p_save == q_save; count++) {
                q_save = inb(mda_status_port) & MDA_STATUS_VSYNC;
                udelay(2);
        }

        if (p_save != q_save) {
                switch (inb_p(mda_status_port) & 0x70) {
                case 0x10:
                        mda_type = TYPE_HERCPLUS;
                        mda_type_name = "HerculesPlus";
                        break;
                case 0x50:
                        mda_type = TYPE_HERCCOLOR;
                        mda_type_name = "HerculesColor";
                        break;
                default:
                        mda_type = TYPE_HERC;
                        mda_type_name = "Hercules";
                        break;
                }
        }

        return 1;
}

static void mda_initialize(void)
{
        write_mda_b(97, 0x00);          /* horizontal total */
        write_mda_b(80, 0x01);          /* horizontal displayed */
        write_mda_b(82, 0x02);          /* horizontal sync pos */
        write_mda_b(15, 0x03);          /* horizontal sync width */

        write_mda_b(25, 0x04);          /* vertical total */
        write_mda_b(6,  0x05);          /* vertical total adjust */
        write_mda_b(25, 0x06);          /* vertical displayed */
        write_mda_b(25, 0x07);          /* vertical sync pos */

        write_mda_b(2,  0x08);          /* interlace mode */
        write_mda_b(13, 0x09);          /* maximum scanline */
        write_mda_b(12, 0x0a);          /* cursor start */
        write_mda_b(13, 0x0b);          /* cursor end */

        write_mda_w(0x0000, 0x0c);      /* start address */
        write_mda_w(0x0000, 0x0e);      /* cursor location */

        outb_p(MDA_MODE_VIDEO_EN | MDA_MODE_BLINK_EN, mda_mode_port);
        outb_p(0x00, mda_status_port);
        outb_p(0x00, mda_gfx_port);
}

static const char *mdacon_startup(void)
{
        mda_num_columns = 80;
        mda_num_lines   = 25;

        mda_vram_len  = 0x01000;
        mda_vram_base = (u16 *)VGA_MAP_MEM(0xb0000, mda_vram_len);

        mda_index_port  = 0x3b4;
        mda_value_port  = 0x3b5;
        mda_mode_port   = 0x3b8;
        mda_status_port = 0x3ba;
        mda_gfx_port    = 0x3bf;

        mda_type = TYPE_MDA;
        mda_type_name = "MDA";

        if (! mda_detect()) {
                printk("mdacon: MDA card not detected.\n");
                return NULL;
        }

        if (mda_type != TYPE_MDA) {
                mda_initialize();
        }

        /* cursor looks ugly during boot-up, so turn it off */
        mda_set_cursor(mda_vram_len - 1);

        printk("mdacon: %s with %ldK of memory detected.\n",
                mda_type_name, mda_vram_len/1024);

        return "MDA-2";
}

static void mdacon_init(struct vc_data *c, bool init)
{
        c->vc_complement_mask = 0x0800;  /* reverse video */
        c->vc_display_fg = &mda_display_fg;

        if (init) {
                c->vc_cols = mda_num_columns;
                c->vc_rows = mda_num_lines;
        } else
                vc_resize(c, mda_num_columns, mda_num_lines);

        /* make the first MDA console visible */

        if (mda_display_fg == NULL)
                mda_display_fg = c;
}

static void mdacon_deinit(struct vc_data *c)
{
        /* con_set_default_unimap(c->vc_num); */

        if (mda_display_fg == c)
                mda_display_fg = NULL;
}

static inline u16 mda_convert_attr(u16 ch)
{
        u16 attr = 0x0700;

        /* Underline and reverse-video are mutually exclusive on MDA.
         * Since reverse-video is used for cursors and selected areas,
         * it takes precedence. 
         */

        if (ch & 0x0800)        attr = 0x7000;  /* reverse */
        else if (ch & 0x0400)   attr = 0x0100;  /* underline */

        return ((ch & 0x0200) << 2) |           /* intensity */ 
                (ch & 0x8000) |                 /* blink */ 
                (ch & 0x00ff) | attr;
}

static u8 mdacon_build_attr(struct vc_data *c, u8 color,
                            enum vc_intensity intensity,
                            bool blink, bool underline, bool reverse,
                            bool italic)
{
        /* The attribute is just a bit vector:
         *
         *      Bit 0..1 : intensity (0..2)
         *      Bit 2    : underline
         *      Bit 3    : reverse
         *      Bit 7    : blink
         */

        return (intensity & VCI_MASK) |
                (underline << 2) |
                (reverse << 3) |
                (italic << 4) |
                (blink << 7);
}

static void mdacon_invert_region(struct vc_data *c, u16 *p, int count)
{
        for (; count > 0; count--) {
                scr_writew(scr_readw(p) ^ 0x0800, p);
                p++;
        }
}

static inline u16 *mda_addr(unsigned int x, unsigned int y)
{
        return mda_vram_base + y * mda_num_columns + x;
}

static void mdacon_putcs(struct vc_data *c, const u16 *s, unsigned int count,
                         unsigned int y, unsigned int x)
{
        u16 *dest = mda_addr(x, y);

        for (; count > 0; count--) {
                scr_writew(mda_convert_attr(scr_readw(s++)), dest++);
        }
}

static void mdacon_clear(struct vc_data *c, unsigned int y, unsigned int x,
                         unsigned int width)
{
        u16 *dest = mda_addr(x, y);
        u16 eattr = mda_convert_attr(c->vc_video_erase_char);

        scr_memsetw(dest, eattr, width * 2);
}

static bool mdacon_switch(struct vc_data *c)
{
        return true;    /* redrawing needed */
}

static bool mdacon_blank(struct vc_data *c, enum vesa_blank_mode blank,
                         bool mode_switch)
{
        if (mda_type == TYPE_MDA) {
                if (blank) 
                        scr_memsetw(mda_vram_base,
                                mda_convert_attr(c->vc_video_erase_char),
                                c->vc_screenbuf_size);
                /* Tell console.c that it has to restore the screen itself */
                return true;
        } else {
                if (blank)
                        outb_p(0x00, mda_mode_port);    /* disable video */
                else
                        outb_p(MDA_MODE_VIDEO_EN | MDA_MODE_BLINK_EN, 
                                mda_mode_port);
                return false;
        }
}

static void mdacon_cursor(struct vc_data *c, bool enable)
{
        if (!enable) {
                mda_set_cursor(mda_vram_len - 1);
                return;
        }

        mda_set_cursor(c->state.y * mda_num_columns * 2 + c->state.x * 2);

        switch (CUR_SIZE(c->vc_cursor_type)) {

                case CUR_LOWER_THIRD:   mda_set_cursor_size(10, 13); break;
                case CUR_LOWER_HALF:    mda_set_cursor_size(7,  13); break;
                case CUR_TWO_THIRDS:    mda_set_cursor_size(4,  13); break;
                case CUR_BLOCK:         mda_set_cursor_size(1,  13); break;
                case CUR_NONE:          mda_set_cursor_size(14, 13); break;
                default:                mda_set_cursor_size(12, 13); break;
        }
}

static bool mdacon_scroll(struct vc_data *c, unsigned int t, unsigned int b,
                enum con_scroll dir, unsigned int lines)
{
        u16 eattr = mda_convert_attr(c->vc_video_erase_char);

        if (!lines)
                return false;

        if (lines > c->vc_rows)   /* maximum realistic size */
                lines = c->vc_rows;

        switch (dir) {

        case SM_UP:
                scr_memmovew(mda_addr(0, t), mda_addr(0, t + lines),
                                (b-t-lines)*mda_num_columns*2);
                scr_memsetw(mda_addr(0, b - lines), eattr,
                                lines*mda_num_columns*2);
                break;

        case SM_DOWN:
                scr_memmovew(mda_addr(0, t + lines), mda_addr(0, t),
                                (b-t-lines)*mda_num_columns*2);
                scr_memsetw(mda_addr(0, t), eattr, lines*mda_num_columns*2);
                break;
        }

        return false;
}


/*
 *  The console `switch' structure for the MDA based console
 */

static const struct consw mda_con = {
        .owner =                THIS_MODULE,
        .con_startup =          mdacon_startup,
        .con_init =             mdacon_init,
        .con_deinit =           mdacon_deinit,
        .con_clear =            mdacon_clear,
        .con_putcs =            mdacon_putcs,
        .con_cursor =           mdacon_cursor,
        .con_scroll =           mdacon_scroll,
        .con_switch =           mdacon_switch,
        .con_blank =            mdacon_blank,
        .con_build_attr =       mdacon_build_attr,
        .con_invert_region =    mdacon_invert_region,
};

int __init mda_console_init(void)
{
        int err;

        if (mda_first_vc > mda_last_vc)
                return 1;
        console_lock();
        err = do_take_over_console(&mda_con, mda_first_vc-1, mda_last_vc-1, 0);
        console_unlock();
        return err;
}

static void __exit mda_console_exit(void)
{
        give_up_console(&mda_con);
}

module_init(mda_console_init);
module_exit(mda_console_exit);

MODULE_DESCRIPTION("MDA based console driver");
MODULE_LICENSE("GPL");