/*
 * linux/drivers/video/hgafb.c -- Hercules graphics adaptor frame buffer device
 * 
 *      Created 25 Nov 1999 by Ferenc Bakonyi (fero@drama.obuda.kando.hu)
 *      Based on skeletonfb.c by Geert Uytterhoeven and
 *               mdacon.c by Andrew Apted
 *
 * History:
 *
 * - Revision 0.1.8 (23 Oct 2002): Ported to new framebuffer api.
 * 
 * - Revision 0.1.7 (23 Jan 2001): fix crash resulting from MDA only cards 
 *                                 being detected as Hercules.   (Paul G.)
 * - Revision 0.1.6 (17 Aug 2000): new style structs
 *                                 documentation
 * - Revision 0.1.5 (13 Mar 2000): spinlocks instead of saveflags();cli();etc
 *                                 minor fixes
 * - Revision 0.1.4 (24 Jan 2000): fixed a bug in hga_card_detect() for 
 *                                  HGA-only systems
 * - Revision 0.1.3 (22 Jan 2000): modified for the new fb_info structure
 *                                 screen is cleared after rmmod
 *                                 virtual resolutions
 *                                 module parameter 'nologo={0|1}'
 *                                 the most important: boot logo :)
 * - Revision 0.1.0  (6 Dec 1999): faster scrolling and minor fixes
 * - First release  (25 Nov 1999)
 *
 * 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/kernel.h>
#include <linux/errno.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <asm/io.h>
#include <asm/vga.h>

#if 0
#define DPRINTK(args...) printk(KERN_DEBUG __FILE__": " ##args)
#else
#define DPRINTK(args...)
#endif

#if 0
#define CHKINFO(ret) if (info != &fb_info) { printk(KERN_DEBUG __FILE__": This should never happen, line:%d \n", __LINE__); return ret; }
#else
#define CHKINFO(ret)
#endif

/* Description of the hardware layout */

static void __iomem *hga_vram;                  /* Base of video memory */
static unsigned long hga_vram_len;              /* Size of video memory */

#define HGA_ROWADDR(row) ((row%4)*8192 + (row>>2)*90)
#define HGA_TXT                 0
#define HGA_GFX                 1

static inline u8 __iomem * rowaddr(struct fb_info *info, u_int row)
{
        return info->screen_base + HGA_ROWADDR(row);
}

static int hga_mode = -1;                       /* 0 = txt, 1 = gfx mode */

static enum { TYPE_HERC, TYPE_HERCPLUS, TYPE_HERCCOLOR } hga_type;
static char *hga_type_name;

#define HGA_INDEX_PORT          0x3b4           /* Register select port */
#define HGA_VALUE_PORT          0x3b5           /* Register value port */
#define HGA_MODE_PORT           0x3b8           /* Mode control port */
#define HGA_STATUS_PORT         0x3ba           /* Status and Config port */
#define HGA_GFX_PORT            0x3bf           /* Graphics control port */

/* HGA register values */

#define HGA_CURSOR_BLINKING     0x00
#define HGA_CURSOR_OFF          0x20
#define HGA_CURSOR_SLOWBLINK    0x60

#define HGA_MODE_GRAPHICS       0x02
#define HGA_MODE_VIDEO_EN       0x08
#define HGA_MODE_BLINK_EN       0x20
#define HGA_MODE_GFX_PAGE1      0x80

#define HGA_STATUS_HSYNC        0x01
#define HGA_STATUS_VSYNC        0x80
#define HGA_STATUS_VIDEO        0x08

#define HGA_CONFIG_COL132       0x08
#define HGA_GFX_MODE_EN         0x01
#define HGA_GFX_PAGE_EN         0x02

/* Global locks */

static DEFINE_SPINLOCK(hga_reg_lock);

/* Framebuffer driver structures */

static const struct fb_var_screeninfo hga_default_var = {
        .xres           = 720,
        .yres           = 348,
        .xres_virtual   = 720,
        .yres_virtual   = 348,
        .bits_per_pixel = 1,
        .red            = {0, 1, 0},
        .green          = {0, 1, 0},
        .blue           = {0, 1, 0},
        .transp         = {0, 0, 0},
        .height         = -1,
        .width          = -1,
};

static struct fb_fix_screeninfo hga_fix = {
        .id             = "HGA",
        .type           = FB_TYPE_PACKED_PIXELS,        /* (not sure) */
        .visual         = FB_VISUAL_MONO10,
        .xpanstep       = 8,
        .ypanstep       = 8,
        .line_length    = 90,
        .accel          = FB_ACCEL_NONE
};

/* Don't assume that tty1 will be the initial current console. */
static int release_io_port = 0;
static int release_io_ports = 0;
static bool nologo = 0;

/* -------------------------------------------------------------------------
 *
 * Low level hardware functions
 *
 * ------------------------------------------------------------------------- */

static void write_hga_b(unsigned int val, unsigned char reg)
{
        outb_p(reg, HGA_INDEX_PORT); 
        outb_p(val, HGA_VALUE_PORT);
}

static void write_hga_w(unsigned int val, unsigned char reg)
{
        outb_p(reg,   HGA_INDEX_PORT); outb_p(val >> 8,   HGA_VALUE_PORT);
        outb_p(reg+1, HGA_INDEX_PORT); outb_p(val & 0xff, HGA_VALUE_PORT);
}

static int test_hga_b(unsigned char val, unsigned char reg)
{
        outb_p(reg, HGA_INDEX_PORT); 
        outb  (val, HGA_VALUE_PORT);
        udelay(20); val = (inb_p(HGA_VALUE_PORT) == val);
        return val;
}

static void hga_clear_screen(void)
{
        unsigned char fillchar = 0xbf; /* magic */
        unsigned long flags;

        spin_lock_irqsave(&hga_reg_lock, flags);
        if (hga_mode == HGA_TXT)
                fillchar = ' ';
        else if (hga_mode == HGA_GFX)
                fillchar = 0x00;
        spin_unlock_irqrestore(&hga_reg_lock, flags);
        if (fillchar != 0xbf)
                memset_io(hga_vram, fillchar, hga_vram_len);
}

static void hga_txt_mode(void)
{
        unsigned long flags;

        spin_lock_irqsave(&hga_reg_lock, flags);
        outb_p(HGA_MODE_VIDEO_EN | HGA_MODE_BLINK_EN, HGA_MODE_PORT);
        outb_p(0x00, HGA_GFX_PORT);
        outb_p(0x00, HGA_STATUS_PORT);

        write_hga_b(0x61, 0x00);        /* horizontal total */
        write_hga_b(0x50, 0x01);        /* horizontal displayed */
        write_hga_b(0x52, 0x02);        /* horizontal sync pos */
        write_hga_b(0x0f, 0x03);        /* horizontal sync width */

        write_hga_b(0x19, 0x04);        /* vertical total */
        write_hga_b(0x06, 0x05);        /* vertical total adjust */
        write_hga_b(0x19, 0x06);        /* vertical displayed */
        write_hga_b(0x19, 0x07);        /* vertical sync pos */

        write_hga_b(0x02, 0x08);        /* interlace mode */
        write_hga_b(0x0d, 0x09);        /* maximum scanline */
        write_hga_b(0x0c, 0x0a);        /* cursor start */
        write_hga_b(0x0d, 0x0b);        /* cursor end */

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

        hga_mode = HGA_TXT;
        spin_unlock_irqrestore(&hga_reg_lock, flags);
}

static void hga_gfx_mode(void)
{
        unsigned long flags;

        spin_lock_irqsave(&hga_reg_lock, flags);
        outb_p(0x00, HGA_STATUS_PORT);
        outb_p(HGA_GFX_MODE_EN, HGA_GFX_PORT);
        outb_p(HGA_MODE_VIDEO_EN | HGA_MODE_GRAPHICS, HGA_MODE_PORT);

        write_hga_b(0x35, 0x00);        /* horizontal total */
        write_hga_b(0x2d, 0x01);        /* horizontal displayed */
        write_hga_b(0x2e, 0x02);        /* horizontal sync pos */
        write_hga_b(0x07, 0x03);        /* horizontal sync width */

        write_hga_b(0x5b, 0x04);        /* vertical total */
        write_hga_b(0x02, 0x05);        /* vertical total adjust */
        write_hga_b(0x57, 0x06);        /* vertical displayed */
        write_hga_b(0x57, 0x07);        /* vertical sync pos */

        write_hga_b(0x02, 0x08);        /* interlace mode */
        write_hga_b(0x03, 0x09);        /* maximum scanline */
        write_hga_b(0x00, 0x0a);        /* cursor start */
        write_hga_b(0x00, 0x0b);        /* cursor end */

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

        hga_mode = HGA_GFX;
        spin_unlock_irqrestore(&hga_reg_lock, flags);
}

static void hga_show_logo(struct fb_info *info)
{
/*
        void __iomem *dest = hga_vram;
        char *logo = linux_logo_bw;
        int x, y;
        
        for (y = 134; y < 134 + 80 ; y++) * this needs some cleanup *
                for (x = 0; x < 10 ; x++)
                        writeb(~*(logo++),(dest + HGA_ROWADDR(y) + x + 40));
*/
}

static void hga_pan(unsigned int xoffset, unsigned int yoffset)
{
        unsigned int base;
        unsigned long flags;
        
        base = (yoffset / 8) * 90 + xoffset;
        spin_lock_irqsave(&hga_reg_lock, flags);
        write_hga_w(base, 0x0c);        /* start address */
        spin_unlock_irqrestore(&hga_reg_lock, flags);
        DPRINTK("hga_pan: base:%d\n", base);
}

static void hga_blank(int blank_mode)
{
        unsigned long flags;

        spin_lock_irqsave(&hga_reg_lock, flags);
        if (blank_mode) {
                outb_p(0x00, HGA_MODE_PORT);    /* disable video */
        } else {
                outb_p(HGA_MODE_VIDEO_EN | HGA_MODE_GRAPHICS, HGA_MODE_PORT);
        }
        spin_unlock_irqrestore(&hga_reg_lock, flags);
}

static int hga_card_detect(void)
{
        int count = 0;
        void __iomem *p, *q;
        unsigned short p_save, q_save;

        hga_vram_len  = 0x08000;

        hga_vram = ioremap(0xb0000, hga_vram_len);
        if (!hga_vram)
                return -ENOMEM;

        if (request_region(0x3b0, 12, "hgafb"))
                release_io_ports = 1;
        if (request_region(0x3bf, 1, "hgafb"))
                release_io_port = 1;

        /* do a memory check */

        p = hga_vram;
        q = hga_vram + 0x01000;

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

        writew(0xaa55, p); if (readw(p) == 0xaa55) count++;
        writew(0x55aa, p); if (readw(p) == 0x55aa) count++;
        writew(p_save, p);

        if (count != 2)
                goto error;

        /* Ok, there is definitely a card registering at the correct
         * memory location, so now we do an I/O port test.
         */
        
        if (!test_hga_b(0x66, 0x0f))        /* cursor low register */
                goto error;

        if (!test_hga_b(0x99, 0x0f))     /* cursor low register */
                goto error;

        /* 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(HGA_STATUS_PORT) & HGA_STATUS_VSYNC;

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

        if (p_save == q_save) 
                goto error;

        switch (inb_p(HGA_STATUS_PORT) & 0x70) {
                case 0x10:
                        hga_type = TYPE_HERCPLUS;
                        hga_type_name = "HerculesPlus";
                        break;
                case 0x50:
                        hga_type = TYPE_HERCCOLOR;
                        hga_type_name = "HerculesColor";
                        break;
                default:
                        hga_type = TYPE_HERC;
                        hga_type_name = "Hercules";
                        break;
        }
        return 0;
error:
        if (release_io_ports)
                release_region(0x3b0, 12);
        if (release_io_port)
                release_region(0x3bf, 1);

        iounmap(hga_vram);

        pr_err("hgafb: HGA card not detected.\n");

        return -EINVAL;
}

/**
 *      hgafb_open - open the framebuffer device
 *      @info: pointer to fb_info object containing info for current hga board
 *      @init: open by console system or userland.
 */

static int hgafb_open(struct fb_info *info, int init)
{
        hga_gfx_mode();
        hga_clear_screen();
        if (!nologo) hga_show_logo(info);
        return 0;
}

/**
 *      hgafb_release - open the framebuffer device
 *      @info: pointer to fb_info object containing info for current hga board
 *      @init: open by console system or userland.
 */

static int hgafb_release(struct fb_info *info, int init)
{
        hga_txt_mode();
        hga_clear_screen();
        return 0;
}

/**
 *      hgafb_setcolreg - set color registers
 *      @regno:register index to set
 *      @red:red value, unused
 *      @green:green value, unused
 *      @blue:blue value, unused
 *      @transp:transparency value, unused
 *      @info:unused
 *
 *      This callback function is used to set the color registers of a HGA
 *      board. Since we have only two fixed colors only @regno is checked.
 *      A zero is returned on success and 1 for failure.
 */

static int hgafb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
                           u_int transp, struct fb_info *info)
{
        if (regno > 1)
                return 1;
        return 0;
}

/**
 *      hga_pan_display - pan or wrap the display
 *      @var:contains new xoffset, yoffset and vmode values
 *      @info:pointer to fb_info object containing info for current hga board
 *
 *      This function looks only at xoffset, yoffset and the %FB_VMODE_YWRAP
 *      flag in @var. If input parameters are correct it calls hga_pan() to 
 *      program the hardware. @info->var is updated to the new values.
 *      A zero is returned on success and %-EINVAL for failure.
 */

static int hgafb_pan_display(struct fb_var_screeninfo *var,
                             struct fb_info *info)
{
        if (var->vmode & FB_VMODE_YWRAP) {
                if (var->yoffset >= info->var.yres_virtual ||
                    var->xoffset)
                        return -EINVAL;
        } else {
                if (var->xoffset + info->var.xres > info->var.xres_virtual
                 || var->yoffset + info->var.yres > info->var.yres_virtual
                 || var->yoffset % 8)
                        return -EINVAL;
        }

        hga_pan(var->xoffset, var->yoffset);
        return 0;
}

/**
 *      hgafb_blank - (un)blank the screen
 *      @blank_mode:blanking method to use
 *      @info:unused
 *      
 *      Blank the screen if blank_mode != 0, else unblank. 
 *      Implements VESA suspend and powerdown modes on hardware that supports 
 *      disabling hsync/vsync:
 *              @blank_mode == 2 means suspend vsync,
 *              @blank_mode == 3 means suspend hsync,
 *              @blank_mode == 4 means powerdown.
 */

static int hgafb_blank(int blank_mode, struct fb_info *info)
{
        hga_blank(blank_mode);
        return 0;
}

/*
 * Accel functions
 */
static void hgafb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
{
        u_int rows, y;
        u8 __iomem *dest;

        y = rect->dy;

        for (rows = rect->height; rows--; y++) {
                dest = rowaddr(info, y) + (rect->dx >> 3);
                switch (rect->rop) {
                case ROP_COPY:
                        memset_io(dest, rect->color, (rect->width >> 3));
                        break;
                case ROP_XOR:
                        fb_writeb(~(fb_readb(dest)), dest);
                        break;
                }
        }
}

static void hgafb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
{
        u_int rows, y1, y2;
        u8 __iomem *src;
        u8 __iomem *dest;

        if (area->dy <= area->sy) {
                y1 = area->sy;
                y2 = area->dy;

                for (rows = area->height; rows--; ) {
                        src = rowaddr(info, y1) + (area->sx >> 3);
                        dest = rowaddr(info, y2) + (area->dx >> 3);
                        memmove(dest, src, (area->width >> 3));
                        y1++;
                        y2++;
                }
        } else {
                y1 = area->sy + area->height - 1;
                y2 = area->dy + area->height - 1;

                for (rows = area->height; rows--;) {
                        src = rowaddr(info, y1) + (area->sx >> 3);
                        dest = rowaddr(info, y2) + (area->dx >> 3);
                        memmove(dest, src, (area->width >> 3));
                        y1--;
                        y2--;
                }
        }
}

static void hgafb_imageblit(struct fb_info *info, const struct fb_image *image)
{
        u8 __iomem *dest;
        u8 *cdat = (u8 *) image->data;
        u_int rows, y = image->dy;
        u_int x;
        u8 d;

        for (rows = image->height; rows--; y++) {
                for (x = 0; x < image->width; x+= 8) {
                        d = *cdat++;
                        dest = rowaddr(info, y) + ((image->dx + x)>> 3);
                        fb_writeb(d, dest);
                }
        }
}

static const struct fb_ops hgafb_ops = {
        .owner          = THIS_MODULE,
        .fb_open        = hgafb_open,
        .fb_release     = hgafb_release,
        .fb_setcolreg   = hgafb_setcolreg,
        .fb_pan_display = hgafb_pan_display,
        .fb_blank       = hgafb_blank,
        .fb_fillrect    = hgafb_fillrect,
        .fb_copyarea    = hgafb_copyarea,
        .fb_imageblit   = hgafb_imageblit,
};
                
/* ------------------------------------------------------------------------- *
 *
 * Functions in fb_info
 * 
 * ------------------------------------------------------------------------- */

/* ------------------------------------------------------------------------- */
    
        /*
         *  Initialization
         */

static int hgafb_probe(struct platform_device *pdev)
{
        struct fb_info *info;
        int ret;

        ret = hga_card_detect();
        if (ret)
                return ret;

        printk(KERN_INFO "hgafb: %s with %ldK of memory detected.\n",
                hga_type_name, hga_vram_len/1024);

        info = framebuffer_alloc(0, &pdev->dev);
        if (!info) {
                iounmap(hga_vram);
                return -ENOMEM;
        }

        hga_fix.smem_start = (unsigned long)hga_vram;
        hga_fix.smem_len = hga_vram_len;

        info->flags = FBINFO_DEFAULT | FBINFO_HWACCEL_YPAN;
        info->var = hga_default_var;
        info->fix = hga_fix;
        info->monspecs.hfmin = 0;
        info->monspecs.hfmax = 0;
        info->monspecs.vfmin = 10000;
        info->monspecs.vfmax = 10000;
        info->monspecs.dpms = 0;
        info->fbops = &hgafb_ops;
        info->screen_base = hga_vram;

        if (register_framebuffer(info) < 0) {
                framebuffer_release(info);
                iounmap(hga_vram);
                return -EINVAL;
        }

        fb_info(info, "%s frame buffer device\n", info->fix.id);
        platform_set_drvdata(pdev, info);
        return 0;
}

static int hgafb_remove(struct platform_device *pdev)
{
        struct fb_info *info = platform_get_drvdata(pdev);

        hga_txt_mode();
        hga_clear_screen();

        if (info) {
                unregister_framebuffer(info);
                framebuffer_release(info);
        }

        iounmap(hga_vram);

        if (release_io_ports)
                release_region(0x3b0, 12);

        if (release_io_port)
                release_region(0x3bf, 1);

        return 0;
}

static struct platform_driver hgafb_driver = {
        .probe = hgafb_probe,
        .remove = hgafb_remove,
        .driver = {
                .name = "hgafb",
        },
};

static struct platform_device *hgafb_device;

static int __init hgafb_init(void)
{
        int ret;

        if (fb_get_options("hgafb", NULL))
                return -ENODEV;

        ret = platform_driver_register(&hgafb_driver);

        if (!ret) {
                hgafb_device = platform_device_register_simple("hgafb", 0, NULL, 0);

                if (IS_ERR(hgafb_device)) {
                        platform_driver_unregister(&hgafb_driver);
                        ret = PTR_ERR(hgafb_device);
                }
        }

        return ret;
}

static void __exit hgafb_exit(void)
{
        platform_device_unregister(hgafb_device);
        platform_driver_unregister(&hgafb_driver);
}

/* -------------------------------------------------------------------------
 *
 *  Modularization
 *
 * ------------------------------------------------------------------------- */

MODULE_AUTHOR("Ferenc Bakonyi (fero@drama.obuda.kando.hu)");
MODULE_DESCRIPTION("FBDev driver for Hercules Graphics Adaptor");
MODULE_LICENSE("GPL");

module_param(nologo, bool, 0);
MODULE_PARM_DESC(nologo, "Disables startup logo if != 0 (default=0)");
module_init(hgafb_init);
module_exit(hgafb_exit);