Revert "fbcon: bgcolor fix"

[linux-2.6] / drivers / video / atafb.c

/*
 * linux/drivers/video/atafb.c -- Atari builtin chipset frame buffer device
 *
 *  Copyright (C) 1994 Martin Schaller & Roman Hodek
 *
 * 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.
 *
 * History:
 *   - 03 Jan 95: Original version by Martin Schaller: The TT driver and
 *                all the device independent stuff
 *   - 09 Jan 95: Roman: I've added the hardware abstraction (hw_switch)
 *                and wrote the Falcon, ST(E), and External drivers
 *                based on the original TT driver.
 *   - 07 May 95: Martin: Added colormap operations for the external driver
 *   - 21 May 95: Martin: Added support for overscan
 *                Andreas: some bug fixes for this
 *   -    Jul 95: Guenther Kelleter <guenther@pool.informatik.rwth-aachen.de>:
 *                Programmable Falcon video modes
 *                (thanks to Christian Cartus for documentation
 *                of VIDEL registers).
 *   - 27 Dec 95: Guenther: Implemented user definable video modes "user[0-7]"
 *                on minor 24...31. "user0" may be set on commandline by
 *                "R<x>;<y>;<depth>". (Makes sense only on Falcon)
 *                Video mode switch on Falcon now done at next VBL interrupt
 *                to avoid the annoying right shift of the screen.
 *   - 23 Sep 97: Juergen: added xres_virtual for cards like ProMST
 *                The external-part is legacy, therefore hardware-specific
 *                functions like panning/hardwarescrolling/blanking isn't
 *                                supported.
 *   - 29 Sep 97: Juergen: added Romans suggestion for pan_display
 *                                (var->xoffset was changed even if no set_screen_base avail.)
 *       - 05 Oct 97: Juergen: extfb (PACKED_PIXEL) is FB_PSEUDOCOLOR 'cause
 *                                we know how to set the colors
 *                                ext_*palette: read from ext_colors (former MV300_colors)
 *                                                          write to ext_colors and RAMDAC
 *
 * To do:
 *   - For the Falcon it is not possible to set random video modes on
 *     SM124 and SC/TV, only the bootup resolution is supported.
 *
 */

#define ATAFB_TT
#define ATAFB_STE
#define ATAFB_EXT
#define ATAFB_FALCON

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>

#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/io.h>

#include <asm/atarihw.h>
#include <asm/atariints.h>
#include <asm/atari_stram.h>

#include <linux/fb.h>
#include <asm/atarikb.h>

#include "c2p.h"
#include "atafb.h"

#define SWITCH_ACIA 0x01                /* modes for switch on OverScan */
#define SWITCH_SND6 0x40
#define SWITCH_SND7 0x80
#define SWITCH_NONE 0x00


#define up(x, r) (((x) + (r) - 1) & ~((r)-1))

        /*
         * Interface to the world
         */

static int atafb_check_var(struct fb_var_screeninfo *var, struct fb_info *info);
static int atafb_set_par(struct fb_info *info);
static int atafb_setcolreg(unsigned int regno, unsigned int red, unsigned int green,
                           unsigned int blue, unsigned int transp,
                           struct fb_info *info);
static int atafb_blank(int blank, struct fb_info *info);
static int atafb_pan_display(struct fb_var_screeninfo *var,
                             struct fb_info *info);
static void atafb_fillrect(struct fb_info *info,
                           const struct fb_fillrect *rect);
static void atafb_copyarea(struct fb_info *info,
                           const struct fb_copyarea *region);
static void atafb_imageblit(struct fb_info *info, const struct fb_image *image);
static int atafb_ioctl(struct fb_info *info, unsigned int cmd,
                       unsigned long arg);


static int default_par;         /* default resolution (0=none) */

static unsigned long default_mem_req;

static int hwscroll = -1;

static int use_hwscroll = 1;

static int sttt_xres = 640, st_yres = 400, tt_yres = 480;
static int sttt_xres_virtual = 640, sttt_yres_virtual = 400;
static int ovsc_offset, ovsc_addlen;

        /*
         * Hardware parameters for current mode
         */

static struct atafb_par {
        void *screen_base;
        int yres_virtual;
        u_long next_line;
        u_long next_plane;
#if defined ATAFB_TT || defined ATAFB_STE
        union {
                struct {
                        int mode;
                        int sync;
                } tt, st;
#endif
#ifdef ATAFB_FALCON
                struct falcon_hw {
                        /* Here are fields for storing a video mode, as direct
                         * parameters for the hardware.
                         */
                        short sync;
                        short line_width;
                        short line_offset;
                        short st_shift;
                        short f_shift;
                        short vid_control;
                        short vid_mode;
                        short xoffset;
                        short hht, hbb, hbe, hdb, hde, hss;
                        short vft, vbb, vbe, vdb, vde, vss;
                        /* auxiliary information */
                        short mono;
                        short ste_mode;
                        short bpp;
                } falcon;
#endif
                /* Nothing needed for external mode */
        } hw;
} current_par;

/* Don't calculate an own resolution, and thus don't change the one found when
 * booting (currently used for the Falcon to keep settings for internal video
 * hardware extensions (e.g. ScreenBlaster)  */
static int DontCalcRes = 0;

#ifdef ATAFB_FALCON
#define HHT hw.falcon.hht
#define HBB hw.falcon.hbb
#define HBE hw.falcon.hbe
#define HDB hw.falcon.hdb
#define HDE hw.falcon.hde
#define HSS hw.falcon.hss
#define VFT hw.falcon.vft
#define VBB hw.falcon.vbb
#define VBE hw.falcon.vbe
#define VDB hw.falcon.vdb
#define VDE hw.falcon.vde
#define VSS hw.falcon.vss
#define VCO_CLOCK25             0x04
#define VCO_CSYPOS              0x10
#define VCO_VSYPOS              0x20
#define VCO_HSYPOS              0x40
#define VCO_SHORTOFFS   0x100
#define VMO_DOUBLE              0x01
#define VMO_INTER               0x02
#define VMO_PREMASK             0x0c
#endif

static struct fb_info fb_info = {
        .fix = {
                .id     = "Atari ",
                .visual = FB_VISUAL_PSEUDOCOLOR,
                .accel  = FB_ACCEL_NONE,
        }
};

static void *screen_base;       /* base address of screen */
static void *real_screen_base;  /* (only for Overscan) */

static int screen_len;

static int current_par_valid;

static int mono_moni;


#ifdef ATAFB_EXT

/* external video handling */
static unsigned int external_xres;
static unsigned int external_xres_virtual;
static unsigned int external_yres;

/*
 * not needed - atafb will never support panning/hardwarescroll with external
 * static unsigned int external_yres_virtual;
 */
static unsigned int external_depth;
static int external_pmode;
static void *external_addr;
static unsigned long external_len;
static unsigned long external_vgaiobase;
static unsigned int external_bitspercol = 6;

/*
 * JOE <joe@amber.dinoco.de>:
 * added card type for external driver, is only needed for
 * colormap handling.
 */
enum cardtype { IS_VGA, IS_MV300 };
static enum cardtype external_card_type = IS_VGA;

/*
 * The MV300 mixes the color registers. So we need an array of munged
 * indices in order to access the correct reg.
 */
static int MV300_reg_1bit[2] = {
        0, 1
};
static int MV300_reg_4bit[16] = {
        0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15
};
static int MV300_reg_8bit[256] = {
        0, 128, 64, 192, 32, 160, 96, 224, 16, 144, 80, 208, 48, 176, 112, 240,
        8, 136, 72, 200, 40, 168, 104, 232, 24, 152, 88, 216, 56, 184, 120, 248,
        4, 132, 68, 196, 36, 164, 100, 228, 20, 148, 84, 212, 52, 180, 116, 244,
        12, 140, 76, 204, 44, 172, 108, 236, 28, 156, 92, 220, 60, 188, 124, 252,
        2, 130, 66, 194, 34, 162, 98, 226, 18, 146, 82, 210, 50, 178, 114, 242,
        10, 138, 74, 202, 42, 170, 106, 234, 26, 154, 90, 218, 58, 186, 122, 250,
        6, 134, 70, 198, 38, 166, 102, 230, 22, 150, 86, 214, 54, 182, 118, 246,
        14, 142, 78, 206, 46, 174, 110, 238, 30, 158, 94, 222, 62, 190, 126, 254,
        1, 129, 65, 193, 33, 161, 97, 225, 17, 145, 81, 209, 49, 177, 113, 241,
        9, 137, 73, 201, 41, 169, 105, 233, 25, 153, 89, 217, 57, 185, 121, 249,
        5, 133, 69, 197, 37, 165, 101, 229, 21, 149, 85, 213, 53, 181, 117, 245,
        13, 141, 77, 205, 45, 173, 109, 237, 29, 157, 93, 221, 61, 189, 125, 253,
        3, 131, 67, 195, 35, 163, 99, 227, 19, 147, 83, 211, 51, 179, 115, 243,
        11, 139, 75, 203, 43, 171, 107, 235, 27, 155, 91, 219, 59, 187, 123, 251,
        7, 135, 71, 199, 39, 167, 103, 231, 23, 151, 87, 215, 55, 183, 119, 247,
        15, 143, 79, 207, 47, 175, 111, 239, 31, 159, 95, 223, 63, 191, 127, 255
};

static int *MV300_reg = MV300_reg_8bit;
#endif /* ATAFB_EXT */


static int inverse;

extern int fontheight_8x8;
extern int fontwidth_8x8;
extern unsigned char fontdata_8x8[];

extern int fontheight_8x16;
extern int fontwidth_8x16;
extern unsigned char fontdata_8x16[];

/*
 * struct fb_ops {
 *      * open/release and usage marking
 *      struct module *owner;
 *      int (*fb_open)(struct fb_info *info, int user);
 *      int (*fb_release)(struct fb_info *info, int user);
 *
 *      * For framebuffers with strange non linear layouts or that do not
 *      * work with normal memory mapped access
 *      ssize_t (*fb_read)(struct file *file, char __user *buf, size_t count, loff_t *ppos);
 *      ssize_t (*fb_write)(struct file *file, const char __user *buf, size_t count, loff_t *ppos);
 *
 *      * checks var and eventually tweaks it to something supported,
 *      * DOES NOT MODIFY PAR *
 *      int (*fb_check_var)(struct fb_var_screeninfo *var, struct fb_info *info);
 *
 *      * set the video mode according to info->var *
 *      int (*fb_set_par)(struct fb_info *info);
 *
 *      * set color register *
 *      int (*fb_setcolreg)(unsigned int regno, unsigned int red, unsigned int green,
 *                          unsigned int blue, unsigned int transp, struct fb_info *info);
 *
 *      * set color registers in batch *
 *      int (*fb_setcmap)(struct fb_cmap *cmap, struct fb_info *info);
 *
 *      * blank display *
 *      int (*fb_blank)(int blank, struct fb_info *info);
 *
 *      * pan display *
 *      int (*fb_pan_display)(struct fb_var_screeninfo *var, struct fb_info *info);
 *
 *      *** The meat of the drawing engine ***
 *      * Draws a rectangle *
 *      void (*fb_fillrect) (struct fb_info *info, const struct fb_fillrect *rect);
 *      * Copy data from area to another *
 *      void (*fb_copyarea) (struct fb_info *info, const struct fb_copyarea *region);
 *      * Draws a image to the display *
 *      void (*fb_imageblit) (struct fb_info *info, const struct fb_image *image);
 *
 *      * Draws cursor *
 *      int (*fb_cursor) (struct fb_info *info, struct fb_cursor *cursor);
 *
 *      * Rotates the display *
 *      void (*fb_rotate)(struct fb_info *info, int angle);
 *
 *      * wait for blit idle, optional *
 *      int (*fb_sync)(struct fb_info *info);
 *
 *      * perform fb specific ioctl (optional) *
 *      int (*fb_ioctl)(struct fb_info *info, unsigned int cmd,
 *                      unsigned long arg);
 *
 *      * Handle 32bit compat ioctl (optional) *
 *      int (*fb_compat_ioctl)(struct fb_info *info, unsigned int cmd,
 *                      unsigned long arg);
 *
 *      * perform fb specific mmap *
 *      int (*fb_mmap)(struct fb_info *info, struct vm_area_struct *vma);
 *
 *      * save current hardware state *
 *      void (*fb_save_state)(struct fb_info *info);
 *
 *      * restore saved state *
 *      void (*fb_restore_state)(struct fb_info *info);
 * } ;
 */


/* ++roman: This structure abstracts from the underlying hardware (ST(e),
 * TT, or Falcon.
 *
 * int (*detect)(void)
 *   This function should detect the current video mode settings and
 *   store them in atafb_predefined[0] for later reference by the
 *   user. Return the index+1 of an equivalent predefined mode or 0
 *   if there is no such.
 *
 * int (*encode_fix)(struct fb_fix_screeninfo *fix,
 *                   struct atafb_par *par)
 *   This function should fill in the 'fix' structure based on the
 *   values in the 'par' structure.
 * !!! Obsolete, perhaps !!!
 *
 * int (*decode_var)(struct fb_var_screeninfo *var,
 *                   struct atafb_par *par)
 *   Get the video params out of 'var'. If a value doesn't fit, round
 *   it up, if it's too big, return EINVAL.
 *   Round up in the following order: bits_per_pixel, xres, yres,
 *   xres_virtual, yres_virtual, xoffset, yoffset, grayscale, bitfields,
 *   horizontal timing, vertical timing.
 *
 * int (*encode_var)(struct fb_var_screeninfo *var,
 *                   struct atafb_par *par);
 *   Fill the 'var' structure based on the values in 'par' and maybe
 *   other values read out of the hardware.
 *
 * void (*get_par)(struct atafb_par *par)
 *   Fill the hardware's 'par' structure.
 *   !!! Used only by detect() !!!
 *
 * void (*set_par)(struct atafb_par *par)
 *   Set the hardware according to 'par'.
 *
 * void (*set_screen_base)(void *s_base)
 *   Set the base address of the displayed frame buffer. Only called
 *   if yres_virtual > yres or xres_virtual > xres.
 *
 * int (*blank)(int blank_mode)
 *   Blank the screen if blank_mode != 0, else unblank. If blank == NULL then
 *   the caller blanks by setting the CLUT to all black. Return 0 if blanking
 *   succeeded, !=0 if un-/blanking failed due to e.g. a video mode which
 *   doesn't support it. Implements VESA suspend and powerdown modes on
 *   hardware that supports disabling hsync/vsync:
 *       blank_mode == 2: suspend vsync, 3:suspend hsync, 4: powerdown.
 */

static struct fb_hwswitch {
        int (*detect)(void);
        int (*encode_fix)(struct fb_fix_screeninfo *fix,
                          struct atafb_par *par);
        int (*decode_var)(struct fb_var_screeninfo *var,
                          struct atafb_par *par);
        int (*encode_var)(struct fb_var_screeninfo *var,
                          struct atafb_par *par);
        void (*get_par)(struct atafb_par *par);
        void (*set_par)(struct atafb_par *par);
        void (*set_screen_base)(void *s_base);
        int (*blank)(int blank_mode);
        int (*pan_display)(struct fb_var_screeninfo *var,
                           struct fb_info *info);
} *fbhw;

static char *autodetect_names[] = { "autodetect", NULL };
static char *stlow_names[] = { "stlow", NULL };
static char *stmid_names[] = { "stmid", "default5", NULL };
static char *sthigh_names[] = { "sthigh", "default4", NULL };
static char *ttlow_names[] = { "ttlow", NULL };
static char *ttmid_names[] = { "ttmid", "default1", NULL };
static char *tthigh_names[] = { "tthigh", "default2", NULL };
static char *vga2_names[] = { "vga2", NULL };
static char *vga4_names[] = { "vga4", NULL };
static char *vga16_names[] = { "vga16", "default3", NULL };
static char *vga256_names[] = { "vga256", NULL };
static char *falh2_names[] = { "falh2", NULL };
static char *falh16_names[] = { "falh16", NULL };

static char **fb_var_names[] = {
        autodetect_names,
        stlow_names,
        stmid_names,
        sthigh_names,
        ttlow_names,
        ttmid_names,
        tthigh_names,
        vga2_names,
        vga4_names,
        vga16_names,
        vga256_names,
        falh2_names,
        falh16_names,
        NULL
};

static struct fb_var_screeninfo atafb_predefined[] = {
        /*
         * yres_virtual == 0 means use hw-scrolling if possible, else yres
         */
        { /* autodetect */
          0, 0, 0, 0, 0, 0, 0, 0,               /* xres-grayscale */
          {0, 0, 0}, {0, 0, 0}, {0, 0, 0}, {0, 0, 0},   /* red green blue tran*/
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* st low */
          320, 200, 320, 0, 0, 0, 4, 0,
          {0, 4, 0}, {0, 4, 0}, {0, 4, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* st mid */
          640, 200, 640, 0, 0, 0, 2, 0,
          {0, 4, 0}, {0, 4, 0}, {0, 4, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* st high */
          640, 400, 640, 0, 0, 0, 1, 0,
          {0, 4, 0}, {0, 4, 0}, {0, 4, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* tt low */
          320, 480, 320, 0, 0, 0, 8, 0,
          {0, 4, 0}, {0, 4, 0}, {0, 4, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* tt mid */
          640, 480, 640, 0, 0, 0, 4, 0,
          {0, 4, 0}, {0, 4, 0}, {0, 4, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* tt high */
          1280, 960, 1280, 0, 0, 0, 1, 0,
          {0, 4, 0}, {0, 4, 0}, {0, 4, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* vga2 */
          640, 480, 640, 0, 0, 0, 1, 0,
          {0, 6, 0}, {0, 6, 0}, {0, 6, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* vga4 */
          640, 480, 640, 0, 0, 0, 2, 0,
          {0, 4, 0}, {0, 4, 0}, {0, 4, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* vga16 */
          640, 480, 640, 0, 0, 0, 4, 0,
          {0, 6, 0}, {0, 6, 0}, {0, 6, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* vga256 */
          640, 480, 640, 0, 0, 0, 8, 0,
          {0, 6, 0}, {0, 6, 0}, {0, 6, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* falh2 */
          896, 608, 896, 0, 0, 0, 1, 0,
          {0, 6, 0}, {0, 6, 0}, {0, 6, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
        { /* falh16 */
          896, 608, 896, 0, 0, 0, 4, 0,
          {0, 6, 0}, {0, 6, 0}, {0, 6, 0}, {0, 0, 0},
          0, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0 },
};

static int num_atafb_predefined = ARRAY_SIZE(atafb_predefined);

static struct fb_videomode atafb_modedb[] __initdata = {
        /*
         *  Atari Video Modes
         *
         *  If you change these, make sure to update DEFMODE_* as well!
         */

        /*
         *  ST/TT Video Modes
         */

        {
                /* 320x200, 15 kHz, 60 Hz (ST low) */
                "st-low", 60, 320, 200, 32000, 32, 16, 31, 14, 96, 4,
                0, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        }, {
                /* 640x200, 15 kHz, 60 Hz (ST medium) */
                "st-mid", 60, 640, 200, 32000, 32, 16, 31, 14, 96, 4,
                0, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        }, {
                /* 640x400, 30.25 kHz, 63.5 Hz (ST high) */
                "st-high", 63, 640, 400, 32000, 128, 0, 40, 14, 128, 4,
                0, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        }, {
                /* 320x480, 15 kHz, 60 Hz (TT low) */
                "tt-low", 60, 320, 480, 31041, 120, 100, 8, 16, 140, 30,
                0, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        }, {
                /* 640x480, 29 kHz, 57 Hz (TT medium) */
                "tt-mid", 60, 640, 480, 31041, 120, 100, 8, 16, 140, 30,
                0, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        }, {
                /* 1280x960, 29 kHz, 60 Hz (TT high) */
                "tt-high", 57, 640, 960, 31041, 120, 100, 8, 16, 140, 30,
                0, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        },

        /*
         *  VGA Video Modes
         */

        {
                /* 640x480, 31 kHz, 60 Hz (VGA) */
                "vga", 63.5, 640, 480, 32000, 18, 42, 31, 11, 96, 3,
                0, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        }, {
                /* 640x400, 31 kHz, 70 Hz (VGA) */
                "vga70", 70, 640, 400, 32000, 18, 42, 31, 11, 96, 3,
                FB_SYNC_VERT_HIGH_ACT | FB_SYNC_COMP_HIGH_ACT, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        },

        /*
         *  Falcon HiRes Video Modes
         */

        {
                /* 896x608, 31 kHz, 60 Hz (Falcon High) */
                "falh", 60, 896, 608, 32000, 18, 42, 31, 1, 96,3,
                0, FB_VMODE_NONINTERLACED | FB_VMODE_YWRAP
        },
};

#define NUM_TOTAL_MODES  ARRAY_SIZE(atafb_modedb)

static char *mode_option __initdata = NULL;

 /* default modes */

#define DEFMODE_TT      5               /* "tt-high" for TT */
#define DEFMODE_F30     7               /* "vga70" for Falcon */
#define DEFMODE_STE     2               /* "st-high" for ST/E */
#define DEFMODE_EXT     6               /* "vga" for external */


static int get_video_mode(char *vname)
{
        char ***name_list;
        char **name;
        int i;

        name_list = fb_var_names;
        for (i = 0; i < num_atafb_predefined; i++) {
                name = *name_list++;
                if (!name || !*name)
                        break;
                while (*name) {
                        if (!strcmp(vname, *name))
                                return i + 1;
                        name++;
                }
        }
        return 0;
}



/* ------------------- TT specific functions ---------------------- */

#ifdef ATAFB_TT

static int tt_encode_fix(struct fb_fix_screeninfo *fix, struct atafb_par *par)
{
        int mode;

        strcpy(fix->id, "Atari Builtin");
        fix->smem_start = (unsigned long)real_screen_base;
        fix->smem_len = screen_len;
        fix->type = FB_TYPE_INTERLEAVED_PLANES;
        fix->type_aux = 2;
        fix->visual = FB_VISUAL_PSEUDOCOLOR;
        mode = par->hw.tt.mode & TT_SHIFTER_MODEMASK;
        if (mode == TT_SHIFTER_TTHIGH || mode == TT_SHIFTER_STHIGH) {
                fix->type = FB_TYPE_PACKED_PIXELS;
                fix->type_aux = 0;
                if (mode == TT_SHIFTER_TTHIGH)
                        fix->visual = FB_VISUAL_MONO01;
        }
        fix->xpanstep = 0;
        fix->ypanstep = 1;
        fix->ywrapstep = 0;
        fix->line_length = 0;
        fix->accel = FB_ACCEL_ATARIBLITT;
        return 0;
}

static int tt_decode_var(struct fb_var_screeninfo *var, struct atafb_par *par)
{
        int xres = var->xres;
        int yres = var->yres;
        int bpp = var->bits_per_pixel;
        int linelen;
        int yres_virtual = var->yres_virtual;

        if (mono_moni) {
                if (bpp > 1 || xres > sttt_xres * 2 || yres > tt_yres * 2)
                        return -EINVAL;
                par->hw.tt.mode = TT_SHIFTER_TTHIGH;
                xres = sttt_xres * 2;
                yres = tt_yres * 2;
                bpp = 1;
        } else {
                if (bpp > 8 || xres > sttt_xres || yres > tt_yres)
                        return -EINVAL;
                if (bpp > 4) {
                        if (xres > sttt_xres / 2 || yres > tt_yres)
                                return -EINVAL;
                        par->hw.tt.mode = TT_SHIFTER_TTLOW;
                        xres = sttt_xres / 2;
                        yres = tt_yres;
                        bpp = 8;
                } else if (bpp > 2) {
                        if (xres > sttt_xres || yres > tt_yres)
                                return -EINVAL;
                        if (xres > sttt_xres / 2 || yres > st_yres / 2) {
                                par->hw.tt.mode = TT_SHIFTER_TTMID;
                                xres = sttt_xres;
                                yres = tt_yres;
                                bpp = 4;
                        } else {
                                par->hw.tt.mode = TT_SHIFTER_STLOW;
                                xres = sttt_xres / 2;
                                yres = st_yres / 2;
                                bpp = 4;
                        }
                } else if (bpp > 1) {
                        if (xres > sttt_xres || yres > st_yres / 2)
                                return -EINVAL;
                        par->hw.tt.mode = TT_SHIFTER_STMID;
                        xres = sttt_xres;
                        yres = st_yres / 2;
                        bpp = 2;
                } else if (var->xres > sttt_xres || var->yres > st_yres) {
                        return -EINVAL;
                } else {
                        par->hw.tt.mode = TT_SHIFTER_STHIGH;
                        xres = sttt_xres;
                        yres = st_yres;
                        bpp = 1;
                }
        }
        if (yres_virtual <= 0)
                yres_virtual = 0;
        else if (yres_virtual < yres)
                yres_virtual = yres;
        if (var->sync & FB_SYNC_EXT)
                par->hw.tt.sync = 0;
        else
                par->hw.tt.sync = 1;
        linelen = xres * bpp / 8;
        if (yres_virtual * linelen > screen_len && screen_len)
                return -EINVAL;
        if (yres * linelen > screen_len && screen_len)
                return -EINVAL;
        if (var->yoffset + yres > yres_virtual && yres_virtual)
                return -EINVAL;
        par->yres_virtual = yres_virtual;
        par->screen_base = screen_base + var->yoffset * linelen;
        return 0;
}

static int tt_encode_var(struct fb_var_screeninfo *var, struct atafb_par *par)
{
        int linelen;
        memset(var, 0, sizeof(struct fb_var_screeninfo));
        var->red.offset = 0;
        var->red.length = 4;
        var->red.msb_right = 0;
        var->grayscale = 0;

        var->pixclock = 31041;
        var->left_margin = 120;         /* these may be incorrect */
        var->right_margin = 100;
        var->upper_margin = 8;
        var->lower_margin = 16;
        var->hsync_len = 140;
        var->vsync_len = 30;

        var->height = -1;
        var->width = -1;

        if (par->hw.tt.sync & 1)
                var->sync = 0;
        else
                var->sync = FB_SYNC_EXT;

        switch (par->hw.tt.mode & TT_SHIFTER_MODEMASK) {
        case TT_SHIFTER_STLOW:
                var->xres = sttt_xres / 2;
                var->xres_virtual = sttt_xres_virtual / 2;
                var->yres = st_yres / 2;
                var->bits_per_pixel = 4;
                break;
        case TT_SHIFTER_STMID:
                var->xres = sttt_xres;
                var->xres_virtual = sttt_xres_virtual;
                var->yres = st_yres / 2;
                var->bits_per_pixel = 2;
                break;
        case TT_SHIFTER_STHIGH:
                var->xres = sttt_xres;
                var->xres_virtual = sttt_xres_virtual;
                var->yres = st_yres;
                var->bits_per_pixel = 1;
                break;
        case TT_SHIFTER_TTLOW:
                var->xres = sttt_xres / 2;
                var->xres_virtual = sttt_xres_virtual / 2;
                var->yres = tt_yres;
                var->bits_per_pixel = 8;
                break;
        case TT_SHIFTER_TTMID:
                var->xres = sttt_xres;
                var->xres_virtual = sttt_xres_virtual;
                var->yres = tt_yres;
                var->bits_per_pixel = 4;
                break;
        case TT_SHIFTER_TTHIGH:
                var->red.length = 0;
                var->xres = sttt_xres * 2;
                var->xres_virtual = sttt_xres_virtual * 2;
                var->yres = tt_yres * 2;
                var->bits_per_pixel = 1;
                break;
        }
        var->blue = var->green = var->red;
        var->transp.offset = 0;
        var->transp.length = 0;
        var->transp.msb_right = 0;
        linelen = var->xres_virtual * var->bits_per_pixel / 8;
        if (!use_hwscroll)
                var->yres_virtual = var->yres;
        else if (screen_len) {
                if (par->yres_virtual)
                        var->yres_virtual = par->yres_virtual;
                else
                        /* yres_virtual == 0 means use maximum */
                        var->yres_virtual = screen_len / linelen;
        } else {
                if (hwscroll < 0)
                        var->yres_virtual = 2 * var->yres;
                else
                        var->yres_virtual = var->yres + hwscroll * 16;
        }
        var->xoffset = 0;
        if (screen_base)
                var->yoffset = (par->screen_base - screen_base) / linelen;
        else
                var->yoffset = 0;
        var->nonstd = 0;
        var->activate = 0;
        var->vmode = FB_VMODE_NONINTERLACED;
        return 0;
}

static void tt_get_par(struct atafb_par *par)
{
        unsigned long addr;
        par->hw.tt.mode = shifter_tt.tt_shiftmode;
        par->hw.tt.sync = shifter.syncmode;
        addr = ((shifter.bas_hi & 0xff) << 16) |
               ((shifter.bas_md & 0xff) << 8)  |
               ((shifter.bas_lo & 0xff));
        par->screen_base = phys_to_virt(addr);
}

static void tt_set_par(struct atafb_par *par)
{
        shifter_tt.tt_shiftmode = par->hw.tt.mode;
        shifter.syncmode = par->hw.tt.sync;
        /* only set screen_base if really necessary */
        if (current_par.screen_base != par->screen_base)
                fbhw->set_screen_base(par->screen_base);
}

static int tt_setcolreg(unsigned int regno, unsigned int red,
                        unsigned int green, unsigned int blue,
                        unsigned int transp, struct fb_info *info)
{
        if ((shifter_tt.tt_shiftmode & TT_SHIFTER_MODEMASK) == TT_SHIFTER_STHIGH)
                regno += 254;
        if (regno > 255)
                return 1;
        tt_palette[regno] = (((red >> 12) << 8) | ((green >> 12) << 4) |
                             (blue >> 12));
        if ((shifter_tt.tt_shiftmode & TT_SHIFTER_MODEMASK) ==
            TT_SHIFTER_STHIGH && regno == 254)
                tt_palette[0] = 0;
        return 0;
}

static int tt_detect(void)
{
        struct atafb_par par;

        /* Determine the connected monitor: The DMA sound must be
         * disabled before reading the MFP GPIP, because the Sound
         * Done Signal and the Monochrome Detect are XORed together!
         *
         * Even on a TT, we should look if there is a DMA sound. It was
         * announced that the Eagle is TT compatible, but only the PCM is
         * missing...
         */
        if (ATARIHW_PRESENT(PCM_8BIT)) {
                tt_dmasnd.ctrl = DMASND_CTRL_OFF;
                udelay(20);             /* wait a while for things to settle down */
        }
        mono_moni = (mfp.par_dt_reg & 0x80) == 0;

        tt_get_par(&par);
        tt_encode_var(&atafb_predefined[0], &par);

        return 1;
}

#endif /* ATAFB_TT */

/* ------------------- Falcon specific functions ---------------------- */

#ifdef ATAFB_FALCON

static int mon_type;            /* Falcon connected monitor */
static int f030_bus_width;      /* Falcon ram bus width (for vid_control) */
#define F_MON_SM        0
#define F_MON_SC        1
#define F_MON_VGA       2
#define F_MON_TV        3

static struct pixel_clock {
        unsigned long f;        /* f/[Hz] */
        unsigned long t;        /* t/[ps] (=1/f) */
        int right, hsync, left; /* standard timing in clock cycles, not pixel */
        /* hsync initialized in falcon_detect() */
        int sync_mask;          /* or-mask for hw.falcon.sync to set this clock */
        int control_mask;       /* ditto, for hw.falcon.vid_control */
} f25 = {
        25175000, 39721, 18, 0, 42, 0x0, VCO_CLOCK25
}, f32 = {
        32000000, 31250, 18, 0, 42, 0x0, 0
}, fext = {
        0, 0, 18, 0, 42, 0x1, 0
};

/* VIDEL-prescale values [mon_type][pixel_length from VCO] */
static int vdl_prescale[4][3] = {
        { 4,2,1 }, { 4,2,1 }, { 4,2,2 }, { 4,2,1 }
};

/* Default hsync timing [mon_type] in picoseconds */
static long h_syncs[4] = { 3000000, 4875000, 4000000, 4875000 };

#ifdef FBCON_HAS_CFB16
static u16 fbcon_cfb16_cmap[16];
#endif

static inline int hxx_prescale(struct falcon_hw *hw)
{
        return hw->ste_mode ? 16
                            : vdl_prescale[mon_type][hw->vid_mode >> 2 & 0x3];
}

static int falcon_encode_fix(struct fb_fix_screeninfo *fix,
                             struct atafb_par *par)
{
        strcpy(fix->id, "Atari Builtin");
        fix->smem_start = (unsigned long)real_screen_base;
        fix->smem_len = screen_len;
        fix->type = FB_TYPE_INTERLEAVED_PLANES;
        fix->type_aux = 2;
        fix->visual = FB_VISUAL_PSEUDOCOLOR;
        fix->xpanstep = 1;
        fix->ypanstep = 1;
        fix->ywrapstep = 0;
        if (par->hw.falcon.mono) {
                fix->type = FB_TYPE_PACKED_PIXELS;
                fix->type_aux = 0;
                /* no smooth scrolling with longword aligned video mem */
                fix->xpanstep = 32;
        } else if (par->hw.falcon.f_shift & 0x100) {
                fix->type = FB_TYPE_PACKED_PIXELS;
                fix->type_aux = 0;
                /* Is this ok or should it be DIRECTCOLOR? */
                fix->visual = FB_VISUAL_TRUECOLOR;
                fix->xpanstep = 2;
        }
        fix->line_length = 0;
        fix->accel = FB_ACCEL_ATARIBLITT;
        return 0;
}

static int falcon_decode_var(struct fb_var_screeninfo *var,
                             struct atafb_par *par)
{
        int bpp = var->bits_per_pixel;
        int xres = var->xres;
        int yres = var->yres;
        int xres_virtual = var->xres_virtual;
        int yres_virtual = var->yres_virtual;
        int left_margin, right_margin, hsync_len;
        int upper_margin, lower_margin, vsync_len;
        int linelen;
        int interlace = 0, doubleline = 0;
        struct pixel_clock *pclock;
        int plen;                       /* width of pixel in clock cycles */
        int xstretch;
        int prescale;
        int longoffset = 0;
        int hfreq, vfreq;
        int hdb_off, hde_off, base_off;
        int gstart, gend1, gend2, align;

/*
        Get the video params out of 'var'. If a value doesn't fit, round
        it up, if it's too big, return EINVAL.
        Round up in the following order: bits_per_pixel, xres, yres,
        xres_virtual, yres_virtual, xoffset, yoffset, grayscale, bitfields,
        horizontal timing, vertical timing.

        There is a maximum of screen resolution determined by pixelclock
        and minimum frame rate -- (X+hmarg.)*(Y+vmarg.)*vfmin <= pixelclock.
        In interlace mode this is     "     *    "     *vfmin <= pixelclock.
        Additional constraints: hfreq.
        Frequency range for multisync monitors is given via command line.
        For TV and SM124 both frequencies are fixed.

        X % 16 == 0 to fit 8x?? font (except 1 bitplane modes must use X%32 == 0)
        Y % 16 == 0 to fit 8x16 font
        Y % 8 == 0 if Y<400

        Currently interlace and doubleline mode in var are ignored.
        On SM124 and TV only the standard resolutions can be used.
*/

        /* Reject uninitialized mode */
        if (!xres || !yres || !bpp)
                return -EINVAL;

        if (mon_type == F_MON_SM && bpp != 1)
                return -EINVAL;

        if (bpp <= 1) {
                bpp = 1;
                par->hw.falcon.f_shift = 0x400;
                par->hw.falcon.st_shift = 0x200;
        } else if (bpp <= 2) {
                bpp = 2;
                par->hw.falcon.f_shift = 0x000;
                par->hw.falcon.st_shift = 0x100;
        } else if (bpp <= 4) {
                bpp = 4;
                par->hw.falcon.f_shift = 0x000;
                par->hw.falcon.st_shift = 0x000;
        } else if (bpp <= 8) {
                bpp = 8;
                par->hw.falcon.f_shift = 0x010;
        } else if (bpp <= 16) {
                bpp = 16;               /* packed pixel mode */
                par->hw.falcon.f_shift = 0x100; /* hicolor, no overlay */
        } else
                return -EINVAL;
        par->hw.falcon.bpp = bpp;

        if (mon_type == F_MON_SM || DontCalcRes) {
                /* Skip all calculations. VGA/TV/SC1224 only supported. */
                struct fb_var_screeninfo *myvar = &atafb_predefined[0];

                if (bpp > myvar->bits_per_pixel ||
                    var->xres > myvar->xres ||
                    var->yres > myvar->yres)
                        return -EINVAL;
                fbhw->get_par(par);     /* Current par will be new par */
                goto set_screen_base;   /* Don't forget this */
        }

        /* Only some fixed resolutions < 640x400 */
        if (xres <= 320)
                xres = 320;
        else if (xres <= 640 && bpp != 16)
                xres = 640;
        if (yres <= 200)
                yres = 200;
        else if (yres <= 240)
                yres = 240;
        else if (yres <= 400)
                yres = 400;

        /* 2 planes must use STE compatibility mode */
        par->hw.falcon.ste_mode = bpp == 2;
        par->hw.falcon.mono = bpp == 1;

        /* Total and visible scanline length must be a multiple of one longword,
         * this and the console fontwidth yields the alignment for xres and
         * xres_virtual.
         * TODO: this way "odd" fontheights are not supported
         *
         * Special case in STE mode: blank and graphic positions don't align,
         * avoid trash at right margin
         */
        if (par->hw.falcon.ste_mode)
                xres = (xres + 63) & ~63;
        else if (bpp == 1)
                xres = (xres + 31) & ~31;
        else
                xres = (xres + 15) & ~15;
        if (yres >= 400)
                yres = (yres + 15) & ~15;
        else
                yres = (yres + 7) & ~7;

        if (xres_virtual < xres)
                xres_virtual = xres;
        else if (bpp == 1)
                xres_virtual = (xres_virtual + 31) & ~31;
        else
                xres_virtual = (xres_virtual + 15) & ~15;

        if (yres_virtual <= 0)
                yres_virtual = 0;
        else if (yres_virtual < yres)
                yres_virtual = yres;

        /* backward bug-compatibility */
        if (var->pixclock > 1)
                var->pixclock -= 1;

        par->hw.falcon.line_width = bpp * xres / 16;
        par->hw.falcon.line_offset = bpp * (xres_virtual - xres) / 16;

        /* single or double pixel width */
        xstretch = (xres < 640) ? 2 : 1;

#if 0 /* SM124 supports only 640x400, this is rejected above */
        if (mon_type == F_MON_SM) {
                if (xres != 640 && yres != 400)
                        return -EINVAL;
                plen = 1;
                pclock = &f32;
                /* SM124-mode is special */
                par->hw.falcon.ste_mode = 1;
                par->hw.falcon.f_shift = 0x000;
                par->hw.falcon.st_shift = 0x200;
                left_margin = hsync_len = 128 / plen;
                right_margin = 0;
                /* TODO set all margins */
        } else
#endif
        if (mon_type == F_MON_SC || mon_type == F_MON_TV) {
                plen = 2 * xstretch;
                if (var->pixclock > f32.t * plen)
                        return -EINVAL;
                pclock = &f32;
                if (yres > 240)
                        interlace = 1;
                if (var->pixclock == 0) {
                        /* set some minimal margins which center the screen */
                        left_margin = 32;
                        right_margin = 18;
                        hsync_len = pclock->hsync / plen;
                        upper_margin = 31;
                        lower_margin = 14;
                        vsync_len = interlace ? 3 : 4;
                } else {
                        left_margin = var->left_margin;
                        right_margin = var->right_margin;
                        hsync_len = var->hsync_len;
                        upper_margin = var->upper_margin;
                        lower_margin = var->lower_margin;
                        vsync_len = var->vsync_len;
                        if (var->vmode & FB_VMODE_INTERLACED) {
                                upper_margin = (upper_margin + 1) / 2;
                                lower_margin = (lower_margin + 1) / 2;
                                vsync_len = (vsync_len + 1) / 2;
                        } else if (var->vmode & FB_VMODE_DOUBLE) {
                                upper_margin *= 2;
                                lower_margin *= 2;
                                vsync_len *= 2;
                        }
                }
        } else {                        /* F_MON_VGA */
                if (bpp == 16)
                        xstretch = 2;   /* Double pixel width only for hicolor */
                /* Default values are used for vert./hor. timing if no pixelclock given. */
                if (var->pixclock == 0) {
                        int linesize;

                        /* Choose master pixelclock depending on hor. timing */
                        plen = 1 * xstretch;
                        if ((plen * xres + f25.right + f25.hsync + f25.left) *
                            fb_info.monspecs.hfmin < f25.f)
                                pclock = &f25;
                        else if ((plen * xres + f32.right + f32.hsync +
                                  f32.left) * fb_info.monspecs.hfmin < f32.f)
                                pclock = &f32;
                        else if ((plen * xres + fext.right + fext.hsync +
                                  fext.left) * fb_info.monspecs.hfmin < fext.f &&
                                 fext.f)
                                pclock = &fext;
                        else
                                return -EINVAL;

                        left_margin = pclock->left / plen;
                        right_margin = pclock->right / plen;
                        hsync_len = pclock->hsync / plen;
                        linesize = left_margin + xres + right_margin + hsync_len;
                        upper_margin = 31;
                        lower_margin = 11;
                        vsync_len = 3;
                } else {
                        /* Choose largest pixelclock <= wanted clock */
                        int i;
                        unsigned long pcl = ULONG_MAX;
                        pclock = 0;
                        for (i = 1; i <= 4; i *= 2) {
                                if (f25.t * i >= var->pixclock &&
                                    f25.t * i < pcl) {
                                        pcl = f25.t * i;
                                        pclock = &f25;
                                }
                                if (f32.t * i >= var->pixclock &&
                                    f32.t * i < pcl) {
                                        pcl = f32.t * i;
                                        pclock = &f32;
                                }
                                if (fext.t && fext.t * i >= var->pixclock &&
                                    fext.t * i < pcl) {
                                        pcl = fext.t * i;
                                        pclock = &fext;
                                }
                        }
                        if (!pclock)
                                return -EINVAL;
                        plen = pcl / pclock->t;

                        left_margin = var->left_margin;
                        right_margin = var->right_margin;
                        hsync_len = var->hsync_len;
                        upper_margin = var->upper_margin;
                        lower_margin = var->lower_margin;
                        vsync_len = var->vsync_len;
                        /* Internal unit is [single lines per (half-)frame] */
                        if (var->vmode & FB_VMODE_INTERLACED) {
                                /* # lines in half frame */
                                /* External unit is [lines per full frame] */
                                upper_margin = (upper_margin + 1) / 2;
                                lower_margin = (lower_margin + 1) / 2;
                                vsync_len = (vsync_len + 1) / 2;
                        } else if (var->vmode & FB_VMODE_DOUBLE) {
                                /* External unit is [double lines per frame] */
                                upper_margin *= 2;
                                lower_margin *= 2;
                                vsync_len *= 2;
                        }
                }
                if (pclock == &fext)
                        longoffset = 1; /* VIDEL doesn't synchronize on short offset */
        }
        /* Is video bus bandwidth (32MB/s) too low for this resolution? */
        /* this is definitely wrong if bus clock != 32MHz */
        if (pclock->f / plen / 8 * bpp > 32000000L)
                return -EINVAL;

        if (vsync_len < 1)
                vsync_len = 1;

        /* include sync lengths in right/lower margin for all calculations */
        right_margin += hsync_len;
        lower_margin += vsync_len;

        /* ! In all calculations of margins we use # of lines in half frame
         * (which is a full frame in non-interlace mode), so we can switch
         * between interlace and non-interlace without messing around
         * with these.
         */
again:
        /* Set base_offset 128 and video bus width */
        par->hw.falcon.vid_control = mon_type | f030_bus_width;
        if (!longoffset)
                par->hw.falcon.vid_control |= VCO_SHORTOFFS;    /* base_offset 64 */
        if (var->sync & FB_SYNC_HOR_HIGH_ACT)
                par->hw.falcon.vid_control |= VCO_HSYPOS;
        if (var->sync & FB_SYNC_VERT_HIGH_ACT)
                par->hw.falcon.vid_control |= VCO_VSYPOS;
        /* Pixelclock */
        par->hw.falcon.vid_control |= pclock->control_mask;
        /* External or internal clock */
        par->hw.falcon.sync = pclock->sync_mask | 0x2;
        /* Pixellength and prescale */
        par->hw.falcon.vid_mode = (2 / plen) << 2;
        if (doubleline)
                par->hw.falcon.vid_mode |= VMO_DOUBLE;
        if (interlace)
                par->hw.falcon.vid_mode |= VMO_INTER;

        /*********************
         * Horizontal timing: unit = [master clock cycles]
         * unit of hxx-registers: [master clock cycles * prescale]
         * Hxx-registers are 9 bit wide
         *
         * 1 line = ((hht + 2) * 2 * prescale) clock cycles
         *
         * graphic output = hdb & 0x200 ?
         *        ((hht + 2) * 2 - hdb + hde) * prescale - hdboff + hdeoff:
         *        (hht + 2  - hdb + hde) * prescale - hdboff + hdeoff
         * (this must be a multiple of plen*128/bpp, on VGA pixels
         *  to the right may be cut off with a bigger right margin)
         *
         * start of graphics relative to start of 1st halfline = hdb & 0x200 ?
         *        (hdb - hht - 2) * prescale + hdboff :
         *        hdb * prescale + hdboff
         *
         * end of graphics relative to start of 1st halfline =
         *        (hde + hht + 2) * prescale + hdeoff
         *********************/
        /* Calculate VIDEL registers */
{
        prescale = hxx_prescale(&par->hw.falcon);
        base_off = par->hw.falcon.vid_control & VCO_SHORTOFFS ? 64 : 128;

        /* Offsets depend on video mode */
        /* Offsets are in clock cycles, divide by prescale to
         * calculate hd[be]-registers
         */
        if (par->hw.falcon.f_shift & 0x100) {
                align = 1;
                hde_off = 0;
                hdb_off = (base_off + 16 * plen) + prescale;
        } else {
                align = 128 / bpp;
                hde_off = ((128 / bpp + 2) * plen);
                if (par->hw.falcon.ste_mode)
                        hdb_off = (64 + base_off + (128 / bpp + 2) * plen) + prescale;
                else
                        hdb_off = (base_off + (128 / bpp + 18) * plen) + prescale;
        }

        gstart = (prescale / 2 + plen * left_margin) / prescale;
        /* gend1 is for hde (gend-gstart multiple of align), shifter's xres */
        gend1 = gstart + roundup(xres, align) * plen / prescale;
        /* gend2 is for hbb, visible xres (rest to gend1 is cut off by hblank) */
        gend2 = gstart + xres * plen / prescale;
        par->HHT = plen * (left_margin + xres + right_margin) /
                           (2 * prescale) - 2;
/*      par->HHT = (gend2 + plen * right_margin / prescale) / 2 - 2;*/

        par->HDB = gstart - hdb_off / prescale;
        par->HBE = gstart;
        if (par->HDB < 0)
                par->HDB += par->HHT + 2 + 0x200;
        par->HDE = gend1 - par->HHT - 2 - hde_off / prescale;
        par->HBB = gend2 - par->HHT - 2;
#if 0
        /* One more Videl constraint: data fetch of two lines must not overlap */
        if ((par->HDB & 0x200) && (par->HDB & ~0x200) - par->HDE <= 5) {
                /* if this happens increase margins, decrease hfreq. */
        }
#endif
        if (hde_off % prescale)
                par->HBB++;             /* compensate for non matching hde and hbb */
        par->HSS = par->HHT + 2 - plen * hsync_len / prescale;
        if (par->HSS < par->HBB)
                par->HSS = par->HBB;
}

        /*  check hor. frequency */
        hfreq = pclock->f / ((par->HHT + 2) * prescale * 2);
        if (hfreq > fb_info.monspecs.hfmax && mon_type != F_MON_VGA) {
                /* ++guenther:   ^^^^^^^^^^^^^^^^^^^ can't remember why I did this */
                /* Too high -> enlarge margin */
                left_margin += 1;
                right_margin += 1;
                goto again;
        }
        if (hfreq > fb_info.monspecs.hfmax || hfreq < fb_info.monspecs.hfmin)
                return -EINVAL;

        /* Vxx-registers */
        /* All Vxx must be odd in non-interlace, since frame starts in the middle
         * of the first displayed line!
         * One frame consists of VFT+1 half lines. VFT+1 must be even in
         * non-interlace, odd in interlace mode for synchronisation.
         * Vxx-registers are 11 bit wide
         */
        par->VBE = (upper_margin * 2 + 1); /* must begin on odd halfline */
        par->VDB = par->VBE;
        par->VDE = yres;
        if (!interlace)
                par->VDE <<= 1;
        if (doubleline)
                par->VDE <<= 1;         /* VDE now half lines per (half-)frame */
        par->VDE += par->VDB;
        par->VBB = par->VDE;
        par->VFT = par->VBB + (lower_margin * 2 - 1) - 1;
        par->VSS = par->VFT + 1 - (vsync_len * 2 - 1);
        /* vbb,vss,vft must be even in interlace mode */
        if (interlace) {
                par->VBB++;
                par->VSS++;
                par->VFT++;
        }

        /* V-frequency check, hope I didn't create any loop here. */
        /* Interlace and doubleline are mutually exclusive. */
        vfreq = (hfreq * 2) / (par->VFT + 1);
        if (vfreq > fb_info.monspecs.vfmax && !doubleline && !interlace) {
                /* Too high -> try again with doubleline */
                doubleline = 1;
                goto again;
        } else if (vfreq < fb_info.monspecs.vfmin && !interlace && !doubleline) {
                /* Too low -> try again with interlace */
                interlace = 1;
                goto again;
        } else if (vfreq < fb_info.monspecs.vfmin && doubleline) {
                /* Doubleline too low -> clear doubleline and enlarge margins */
                int lines;
                doubleline = 0;
                for (lines = 0;
                     (hfreq * 2) / (par->VFT + 1 + 4 * lines - 2 * yres) >
                     fb_info.monspecs.vfmax;
                     lines++)
                        ;
                upper_margin += lines;
                lower_margin += lines;
                goto again;
        } else if (vfreq > fb_info.monspecs.vfmax && doubleline) {
                /* Doubleline too high -> enlarge margins */
                int lines;
                for (lines = 0;
                     (hfreq * 2) / (par->VFT + 1 + 4 * lines) >
                     fb_info.monspecs.vfmax;
                     lines += 2)
                        ;
                upper_margin += lines;
                lower_margin += lines;
                goto again;
        } else if (vfreq > fb_info.monspecs.vfmax && interlace) {
                /* Interlace, too high -> enlarge margins */
                int lines;
                for (lines = 0;
                     (hfreq * 2) / (par->VFT + 1 + 4 * lines) >
                     fb_info.monspecs.vfmax;
                     lines++)
                        ;
                upper_margin += lines;
                lower_margin += lines;
                goto again;
        } else if (vfreq < fb_info.monspecs.vfmin ||
                   vfreq > fb_info.monspecs.vfmax)
                return -EINVAL;

set_screen_base:
        linelen = xres_virtual * bpp / 8;
        if (yres_virtual * linelen > screen_len && screen_len)
                return -EINVAL;
        if (yres * linelen > screen_len && screen_len)
                return -EINVAL;
        if (var->yoffset + yres > yres_virtual && yres_virtual)
                return -EINVAL;
        par->yres_virtual = yres_virtual;
        par->screen_base = screen_base + var->yoffset * linelen;
        par->hw.falcon.xoffset = 0;

        // FIXME!!! sort of works, no crash
        //par->next_line = linelen;
        //par->next_plane = yres_virtual * linelen;
        par->next_line = linelen;
        par->next_plane = 2;
        // crashes
        //par->next_plane = linelen;
        //par->next_line  = yres_virtual * linelen;

        return 0;
}

static int falcon_encode_var(struct fb_var_screeninfo *var,
                             struct atafb_par *par)
{
/* !!! only for VGA !!! */
        int linelen;
        int prescale, plen;
        int hdb_off, hde_off, base_off;
        struct falcon_hw *hw = &par->hw.falcon;

        memset(var, 0, sizeof(struct fb_var_screeninfo));
        /* possible frequencies: 25.175 or 32MHz */
        var->pixclock = hw->sync & 0x1 ? fext.t :
                        hw->vid_control & VCO_CLOCK25 ? f25.t : f32.t;

        var->height = -1;
        var->width = -1;

        var->sync = 0;
        if (hw->vid_control & VCO_HSYPOS)
                var->sync |= FB_SYNC_HOR_HIGH_ACT;
        if (hw->vid_control & VCO_VSYPOS)
                var->sync |= FB_SYNC_VERT_HIGH_ACT;

        var->vmode = FB_VMODE_NONINTERLACED;
        if (hw->vid_mode & VMO_INTER)
                var->vmode |= FB_VMODE_INTERLACED;
        if (hw->vid_mode & VMO_DOUBLE)
                var->vmode |= FB_VMODE_DOUBLE;

        /* visible y resolution:
         * Graphics display starts at line VDB and ends at line
         * VDE. If interlace mode off unit of VC-registers is
         * half lines, else lines.
         */
        var->yres = hw->vde - hw->vdb;
        if (!(var->vmode & FB_VMODE_INTERLACED))
                var->yres >>= 1;
        if (var->vmode & FB_VMODE_DOUBLE)
                var->yres >>= 1;

        /*
         * to get bpp, we must examine f_shift and st_shift.
         * f_shift is valid if any of bits no. 10, 8 or 4
         * is set. Priority in f_shift is: 10 ">" 8 ">" 4, i.e.
         * if bit 10 set then bit 8 and bit 4 don't care...
         * If all these bits are 0 get display depth from st_shift
         * (as for ST and STE)
         */
        if (hw->f_shift & 0x400)        /* 2 colors */
                var->bits_per_pixel = 1;
        else if (hw->f_shift & 0x100)   /* hicolor */
                var->bits_per_pixel = 16;
        else if (hw->f_shift & 0x010)   /* 8 bitplanes */
                var->bits_per_pixel = 8;
        else if (hw->st_shift == 0)
                var->bits_per_pixel = 4;
        else if (hw->st_shift == 0x100)
                var->bits_per_pixel = 2;
        else                            /* if (hw->st_shift == 0x200) */
                var->bits_per_pixel = 1;

        var->xres = hw->line_width * 16 / var->bits_per_pixel;
        var->xres_virtual = var->xres + hw->line_offset * 16 / var->bits_per_pixel;
        if (hw->xoffset)
                var->xres_virtual += 16;

        if (var->bits_per_pixel == 16) {
                var->red.offset = 11;
                var->red.length = 5;
                var->red.msb_right = 0;
                var->green.offset = 5;
                var->green.length = 6;
                var->green.msb_right = 0;
                var->blue.offset = 0;
                var->blue.length = 5;
                var->blue.msb_right = 0;
        } else {
                var->red.offset = 0;
                var->red.length = hw->ste_mode ? 4 : 6;
                if (var->red.length > var->bits_per_pixel)
                        var->red.length = var->bits_per_pixel;
                var->red.msb_right = 0;
                var->grayscale = 0;
                var->blue = var->green = var->red;
        }
        var->transp.offset = 0;
        var->transp.length = 0;
        var->transp.msb_right = 0;

        linelen = var->xres_virtual * var->bits_per_pixel / 8;
        if (screen_len) {
                if (par->yres_virtual)
                        var->yres_virtual = par->yres_virtual;
                else
                        /* yres_virtual == 0 means use maximum */
                        var->yres_virtual = screen_len / linelen;
        } else {
                if (hwscroll < 0)
                        var->yres_virtual = 2 * var->yres;
                else
                        var->yres_virtual = var->yres + hwscroll * 16;
        }
        var->xoffset = 0;               /* TODO change this */

        /* hdX-offsets */
        prescale = hxx_prescale(hw);
        plen = 4 >> (hw->vid_mode >> 2 & 0x3);
        base_off = hw->vid_control & VCO_SHORTOFFS ? 64 : 128;
        if (hw->f_shift & 0x100) {
                hde_off = 0;
                hdb_off = (base_off + 16 * plen) + prescale;
        } else {
                hde_off = ((128 / var->bits_per_pixel + 2) * plen);
                if (hw->ste_mode)
                        hdb_off = (64 + base_off + (128 / var->bits_per_pixel + 2) * plen)
                                         + prescale;
                else
                        hdb_off = (base_off + (128 / var->bits_per_pixel + 18) * plen)
                                         + prescale;
        }

        /* Right margin includes hsync */
        var->left_margin = hdb_off + prescale * ((hw->hdb & 0x1ff) -
                                           (hw->hdb & 0x200 ? 2 + hw->hht : 0));
        if (hw->ste_mode || mon_type != F_MON_VGA)
                var->right_margin = prescale * (hw->hht + 2 - hw->hde) - hde_off;
        else
                /* can't use this in ste_mode, because hbb is +1 off */
                var->right_margin = prescale * (hw->hht + 2 - hw->hbb);
        var->hsync_len = prescale * (hw->hht + 2 - hw->hss);

        /* Lower margin includes vsync */
        var->upper_margin = hw->vdb / 2;        /* round down to full lines */
        var->lower_margin = (hw->vft + 1 - hw->vde + 1) / 2;    /* round up */
        var->vsync_len = (hw->vft + 1 - hw->vss + 1) / 2;       /* round up */
        if (var->vmode & FB_VMODE_INTERLACED) {
                var->upper_margin *= 2;
                var->lower_margin *= 2;
                var->vsync_len *= 2;
        } else if (var->vmode & FB_VMODE_DOUBLE) {
                var->upper_margin = (var->upper_margin + 1) / 2;
                var->lower_margin = (var->lower_margin + 1) / 2;
                var->vsync_len = (var->vsync_len + 1) / 2;
        }

        var->pixclock *= plen;
        var->left_margin /= plen;
        var->right_margin /= plen;
        var->hsync_len /= plen;

        var->right_margin -= var->hsync_len;
        var->lower_margin -= var->vsync_len;

        if (screen_base)
                var->yoffset = (par->screen_base - screen_base) / linelen;
        else
                var->yoffset = 0;
        var->nonstd = 0;                /* what is this for? */
        var->activate = 0;
        return 0;
}

static int f_change_mode;
static struct falcon_hw f_new_mode;
static int f_pan_display;

static void falcon_get_par(struct atafb_par *par)
{
        unsigned long addr;
        struct falcon_hw *hw = &par->hw.falcon;

        hw->line_width = shifter_f030.scn_width;
        hw->line_offset = shifter_f030.off_next;
        hw->st_shift = videl.st_shift & 0x300;
        hw->f_shift = videl.f_shift;
        hw->vid_control = videl.control;
        hw->vid_mode = videl.mode;
        hw->sync = shifter.syncmode & 0x1;
        hw->xoffset = videl.xoffset & 0xf;
        hw->hht = videl.hht;
        hw->hbb = videl.hbb;
        hw->hbe = videl.hbe;
        hw->hdb = videl.hdb;
        hw->hde = videl.hde;
        hw->hss = videl.hss;
        hw->vft = videl.vft;
        hw->vbb = videl.vbb;
        hw->vbe = videl.vbe;
        hw->vdb = videl.vdb;
        hw->vde = videl.vde;
        hw->vss = videl.vss;

        addr = (shifter.bas_hi & 0xff) << 16 |
               (shifter.bas_md & 0xff) << 8  |
               (shifter.bas_lo & 0xff);
        par->screen_base = phys_to_virt(addr);

        /* derived parameters */
        hw->ste_mode = (hw->f_shift & 0x510) == 0 && hw->st_shift == 0x100;
        hw->mono = (hw->f_shift & 0x400) ||
                   ((hw->f_shift & 0x510) == 0 && hw->st_shift == 0x200);
}

static void falcon_set_par(struct atafb_par *par)
{
        f_change_mode = 0;

        /* only set screen_base if really necessary */
        if (current_par.screen_base != par->screen_base)
                fbhw->set_screen_base(par->screen_base);

        /* Don't touch any other registers if we keep the default resolution */
        if (DontCalcRes)
                return;

        /* Tell vbl-handler to change video mode.
         * We change modes only on next VBL, to avoid desynchronisation
         * (a shift to the right and wrap around by a random number of pixels
         * in all monochrome modes).
         * This seems to work on my Falcon.
         */
        f_new_mode = par->hw.falcon;
        f_change_mode = 1;
}

static irqreturn_t falcon_vbl_switcher(int irq, void *dummy)
{
        struct falcon_hw *hw = &f_new_mode;

        if (f_change_mode) {
                f_change_mode = 0;

                if (hw->sync & 0x1) {
                        /* Enable external pixelclock. This code only for ScreenWonder */
                        *(volatile unsigned short *)0xffff9202 = 0xffbf;
                } else {
                        /* Turn off external clocks. Read sets all output bits to 1. */
                        *(volatile unsigned short *)0xffff9202;
                }
                shifter.syncmode = hw->sync;

                videl.hht = hw->hht;
                videl.hbb = hw->hbb;
                videl.hbe = hw->hbe;
                videl.hdb = hw->hdb;
                videl.hde = hw->hde;
                videl.hss = hw->hss;
                videl.vft = hw->vft;
                videl.vbb = hw->vbb;
                videl.vbe = hw->vbe;
                videl.vdb = hw->vdb;
                videl.vde = hw->vde;
                videl.vss = hw->vss;

                videl.f_shift = 0;      /* write enables Falcon palette, 0: 4 planes */
                if (hw->ste_mode) {
                        videl.st_shift = hw->st_shift;  /* write enables STE palette */
                } else {
                        /* IMPORTANT:
                         * set st_shift 0, so we can tell the screen-depth if f_shift == 0.
                         * Writing 0 to f_shift enables 4 plane Falcon mode but
                         * doesn't set st_shift. st_shift != 0 (!= 4planes) is impossible
                         * with Falcon palette.
                         */
                        videl.st_shift = 0;
                        /* now back to Falcon palette mode */
                        videl.f_shift = hw->f_shift;
                }
                /* writing to st_shift changed scn_width and vid_mode */
                videl.xoffset = hw->xoffset;
                shifter_f030.scn_width = hw->line_width;
                shifter_f030.off_next = hw->line_offset;
                videl.control = hw->vid_control;
                videl.mode = hw->vid_mode;
        }
        if (f_pan_display) {
                f_pan_display = 0;
                videl.xoffset = current_par.hw.falcon.xoffset;
                shifter_f030.off_next = current_par.hw.falcon.line_offset;
        }
        return IRQ_HANDLED;
}

static int falcon_pan_display(struct fb_var_screeninfo *var,
                              struct fb_info *info)
{
        struct atafb_par *par = (struct atafb_par *)info->par;

        int xoffset;
        int bpp = info->var.bits_per_pixel;

        if (bpp == 1)
                var->xoffset = up(var->xoffset, 32);
        if (bpp != 16)
                par->hw.falcon.xoffset = var->xoffset & 15;
        else {
                par->hw.falcon.xoffset = 0;
                var->xoffset = up(var->xoffset, 2);
        }
        par->hw.falcon.line_offset = bpp *
                (info->var.xres_virtual - info->var.xres) / 16;
        if (par->hw.falcon.xoffset)
                par->hw.falcon.line_offset -= bpp;
        xoffset = var->xoffset - par->hw.falcon.xoffset;

        par->screen_base = screen_base +
                (var->yoffset * info->var.xres_virtual + xoffset) * bpp / 8;
        if (fbhw->set_screen_base)
                fbhw->set_screen_base(par->screen_base);
        else
                return -EINVAL;         /* shouldn't happen */
        f_pan_display = 1;
        return 0;
}

static int falcon_setcolreg(unsigned int regno, unsigned int red,
                            unsigned int green, unsigned int blue,
                            unsigned int transp, struct fb_info *info)
{
        if (regno > 255)
                return 1;
        f030_col[regno] = (((red & 0xfc00) << 16) |
                           ((green & 0xfc00) << 8) |
                           ((blue & 0xfc00) >> 8));
        if (regno < 16) {
                shifter_tt.color_reg[regno] =
                        (((red & 0xe000) >> 13) | ((red & 0x1000) >> 12) << 8) |
                        (((green & 0xe000) >> 13) | ((green & 0x1000) >> 12) << 4) |
                        ((blue & 0xe000) >> 13) | ((blue & 0x1000) >> 12);
#ifdef FBCON_HAS_CFB16
                fbcon_cfb16_cmap[regno] = ((red & 0xf800) |
                                           ((green & 0xfc00) >> 5) |
                                           ((blue & 0xf800) >> 11));
#endif
        }
        return 0;
}

static int falcon_blank(int blank_mode)
{
        /* ++guenther: we can switch off graphics by changing VDB and VDE,
         * so VIDEL doesn't hog the bus while saving.
         * (this may affect usleep()).
         */
        int vdb, vss, hbe, hss;

        if (mon_type == F_MON_SM)       /* this doesn't work on SM124 */
                return 1;

        vdb = current_par.VDB;
        vss = current_par.VSS;
        hbe = current_par.HBE;
        hss = current_par.HSS;

        if (blank_mode >= 1) {
                /* disable graphics output (this speeds up the CPU) ... */
                vdb = current_par.VFT + 1;
                /* ... and blank all lines */
                hbe = current_par.HHT + 2;
        }
        /* use VESA suspend modes on VGA monitors */
        if (mon_type == F_MON_VGA) {
                if (blank_mode == 2 || blank_mode == 4)
                        vss = current_par.VFT + 1;
                if (blank_mode == 3 || blank_mode == 4)
                        hss = current_par.HHT + 2;
        }

        videl.vdb = vdb;
        videl.vss = vss;
        videl.hbe = hbe;
        videl.hss = hss;

        return 0;
}

static int falcon_detect(void)
{
        struct atafb_par par;
        unsigned char fhw;

        /* Determine connected monitor and set monitor parameters */
        fhw = *(unsigned char *)0xffff8006;
        mon_type = fhw >> 6 & 0x3;
        /* bit 1 of fhw: 1=32 bit ram bus, 0=16 bit */
        f030_bus_width = fhw << 6 & 0x80;
        switch (mon_type) {
        case F_MON_SM:
                fb_info.monspecs.vfmin = 70;
                fb_info.monspecs.vfmax = 72;
                fb_info.monspecs.hfmin = 35713;
                fb_info.monspecs.hfmax = 35715;
                break;
        case F_MON_SC:
        case F_MON_TV:
                /* PAL...NTSC */
                fb_info.monspecs.vfmin = 49;    /* not 50, since TOS defaults to 49.9x Hz */
                fb_info.monspecs.vfmax = 60;
                fb_info.monspecs.hfmin = 15620;
                fb_info.monspecs.hfmax = 15755;
                break;
        }
        /* initialize hsync-len */
        f25.hsync = h_syncs[mon_type] / f25.t;
        f32.hsync = h_syncs[mon_type] / f32.t;
        if (fext.t)
                fext.hsync = h_syncs[mon_type] / fext.t;

        falcon_get_par(&par);
        falcon_encode_var(&atafb_predefined[0], &par);

        /* Detected mode is always the "autodetect" slot */
        return 1;
}

#endif /* ATAFB_FALCON */

/* ------------------- ST(E) specific functions ---------------------- */

#ifdef ATAFB_STE

static int stste_encode_fix(struct fb_fix_screeninfo *fix,
                            struct atafb_par *par)
{
        int mode;

        strcpy(fix->id, "Atari Builtin");
        fix->smem_start = (unsigned long)real_screen_base;
        fix->smem_len = screen_len;
        fix->type = FB_TYPE_INTERLEAVED_PLANES;
        fix->type_aux = 2;
        fix->visual = FB_VISUAL_PSEUDOCOLOR;
        mode = par->hw.st.mode & 3;
        if (mode == ST_HIGH) {
                fix->type = FB_TYPE_PACKED_PIXELS;
                fix->type_aux = 0;
                fix->visual = FB_VISUAL_MONO10;
        }
        if (ATARIHW_PRESENT(EXTD_SHIFTER)) {
                fix->xpanstep = 16;
                fix->ypanstep = 1;
        } else {
                fix->xpanstep = 0;
                fix->ypanstep = 0;
        }
        fix->ywrapstep = 0;
        fix->line_length = 0;
        fix->accel = FB_ACCEL_ATARIBLITT;
        return 0;
}

static int stste_decode_var(struct fb_var_screeninfo *var,
                            struct atafb_par *par)
{
        int xres = var->xres;
        int yres = var->yres;
        int bpp = var->bits_per_pixel;
        int linelen;
        int yres_virtual = var->yres_virtual;

        if (mono_moni) {
                if (bpp > 1 || xres > sttt_xres || yres > st_yres)
                        return -EINVAL;
                par->hw.st.mode = ST_HIGH;
                xres = sttt_xres;
                yres = st_yres;
                bpp = 1;
        } else {
                if (bpp > 4 || xres > sttt_xres || yres > st_yres)
                        return -EINVAL;
                if (bpp > 2) {
                        if (xres > sttt_xres / 2 || yres > st_yres / 2)
                                return -EINVAL;
                        par->hw.st.mode = ST_LOW;
                        xres = sttt_xres / 2;
                        yres = st_yres / 2;
                        bpp = 4;
                } else if (bpp > 1) {
                        if (xres > sttt_xres || yres > st_yres / 2)
                                return -EINVAL;
                        par->hw.st.mode = ST_MID;
                        xres = sttt_xres;
                        yres = st_yres / 2;
                        bpp = 2;
                } else
                        return -EINVAL;
        }
        if (yres_virtual <= 0)
                yres_virtual = 0;
        else if (yres_virtual < yres)
                yres_virtual = yres;
        if (var->sync & FB_SYNC_EXT)
                par->hw.st.sync = (par->hw.st.sync & ~1) | 1;
        else
                par->hw.st.sync = (par->hw.st.sync & ~1);
        linelen = xres * bpp / 8;
        if (yres_virtual * linelen > screen_len && screen_len)
                return -EINVAL;
        if (yres * linelen > screen_len && screen_len)
                return -EINVAL;
        if (var->yoffset + yres > yres_virtual && yres_virtual)
                return -EINVAL;
        par->yres_virtual = yres_virtual;
        par->screen_base = screen_base + var->yoffset * linelen;
        return 0;
}

static int stste_encode_var(struct fb_var_screeninfo *var,
                            struct atafb_par *par)
{
        int linelen;
        memset(var, 0, sizeof(struct fb_var_screeninfo));
        var->red.offset = 0;
        var->red.length = ATARIHW_PRESENT(EXTD_SHIFTER) ? 4 : 3;
        var->red.msb_right = 0;
        var->grayscale = 0;

        var->pixclock = 31041;
        var->left_margin = 120;         /* these are incorrect */
        var->right_margin = 100;
        var->upper_margin = 8;
        var->lower_margin = 16;
        var->hsync_len = 140;
        var->vsync_len = 30;

        var->height = -1;
        var->width = -1;

        if (!(par->hw.st.sync & 1))
                var->sync = 0;
        else
                var->sync = FB_SYNC_EXT;

        switch (par->hw.st.mode & 3) {
        case ST_LOW:
                var->xres = sttt_xres / 2;
                var->yres = st_yres / 2;
                var->bits_per_pixel = 4;
                break;
        case ST_MID:
                var->xres = sttt_xres;
                var->yres = st_yres / 2;
                var->bits_per_pixel = 2;
                break;
        case ST_HIGH:
                var->xres = sttt_xres;
                var->yres = st_yres;
                var->bits_per_pixel = 1;
                break;
        }
        var->blue = var->green = var->red;
        var->transp.offset = 0;
        var->transp.length = 0;
        var->transp.msb_right = 0;
        var->xres_virtual = sttt_xres_virtual;
        linelen = var->xres_virtual * var->bits_per_pixel / 8;
        ovsc_addlen = linelen * (sttt_yres_virtual - st_yres);

        if (!use_hwscroll)
                var->yres_virtual = var->yres;
        else if (screen_len) {
                if (par->yres_virtual)
                        var->yres_virtual = par->yres_virtual;
                else
                        /* yres_virtual == 0 means use maximum */
                        var->yres_virtual = screen_len / linelen;
        } else {
                if (hwscroll < 0)
                        var->yres_virtual = 2 * var->yres;
                else
                        var->yres_virtual = var->yres + hwscroll * 16;
        }
        var->xoffset = 0;
        if (screen_base)
                var->yoffset = (par->screen_base - screen_base) / linelen;
        else
                var->yoffset = 0;
        var->nonstd = 0;
        var->activate = 0;
        var->vmode = FB_VMODE_NONINTERLACED;
        return 0;
}

static void stste_get_par(struct atafb_par *par)
{
        unsigned long addr;
        par->hw.st.mode = shifter_tt.st_shiftmode;
        par->hw.st.sync = shifter.syncmode;
        addr = ((shifter.bas_hi & 0xff) << 16) |
               ((shifter.bas_md & 0xff) << 8);
        if (ATARIHW_PRESENT(EXTD_SHIFTER))
                addr |= (shifter.bas_lo & 0xff);
        par->screen_base = phys_to_virt(addr);
}

static void stste_set_par(struct atafb_par *par)
{
        shifter_tt.st_shiftmode = par->hw.st.mode;
        shifter.syncmode = par->hw.st.sync;
        /* only set screen_base if really necessary */
        if (current_par.screen_base != par->screen_base)
                fbhw->set_screen_base(par->screen_base);
}

static int stste_setcolreg(unsigned int regno, unsigned int red,
                           unsigned int green, unsigned int blue,
                           unsigned int transp, struct fb_info *info)
{
        if (regno > 15)
                return 1;
        red >>= 12;
        blue >>= 12;
        green >>= 12;
        if (ATARIHW_PRESENT(EXTD_SHIFTER))
                shifter_tt.color_reg[regno] =
                        (((red & 0xe) >> 1) | ((red & 1) << 3) << 8) |
                        (((green & 0xe) >> 1) | ((green & 1) << 3) << 4) |
                        ((blue & 0xe) >> 1) | ((blue & 1) << 3);
        else
                shifter_tt.color_reg[regno] =
                        ((red & 0xe) << 7) |
                        ((green & 0xe) << 3) |
                        ((blue & 0xe) >> 1);
        return 0;
}

static int stste_detect(void)
{
        struct atafb_par par;

        /* Determine the connected monitor: The DMA sound must be
         * disabled before reading the MFP GPIP, because the Sound
         * Done Signal and the Monochrome Detect are XORed together!
         */
        if (ATARIHW_PRESENT(PCM_8BIT)) {
                tt_dmasnd.ctrl = DMASND_CTRL_OFF;
                udelay(20);             /* wait a while for things to settle down */
        }
        mono_moni = (mfp.par_dt_reg & 0x80) == 0;

        stste_get_par(&par);
        stste_encode_var(&atafb_predefined[0], &par);

        if (!ATARIHW_PRESENT(EXTD_SHIFTER))
                use_hwscroll = 0;
        return 1;
}

static void stste_set_screen_base(void *s_base)
{
        unsigned long addr;
        addr = virt_to_phys(s_base);
        /* Setup Screen Memory */
        shifter.bas_hi = (unsigned char)((addr & 0xff0000) >> 16);
        shifter.bas_md = (unsigned char)((addr & 0x00ff00) >> 8);
        if (ATARIHW_PRESENT(EXTD_SHIFTER))
                shifter.bas_lo = (unsigned char)(addr & 0x0000ff);
}

#endif /* ATAFB_STE */

/* Switching the screen size should be done during vsync, otherwise
 * the margins may get messed up. This is a well known problem of
 * the ST's video system.
 *
 * Unfortunately there is hardly any way to find the vsync, as the
 * vertical blank interrupt is no longer in time on machines with
 * overscan type modifications.
 *
 * We can, however, use Timer B to safely detect the black shoulder,
 * but then we've got to guess an appropriate delay to find the vsync.
 * This might not work on every machine.
 *
 * martin_rogge @ ki.maus.de, 8th Aug 1995
 */

#define LINE_DELAY  (mono_moni ? 30 : 70)
#define SYNC_DELAY  (mono_moni ? 1500 : 2000)

/* SWITCH_ACIA may be used for Falcon (ScreenBlaster III internal!) */
static void st_ovsc_switch(void)
{
        unsigned long flags;
        register unsigned char old, new;

        if (!(atari_switches & ATARI_SWITCH_OVSC_MASK))
                return;
        local_irq_save(flags);

        mfp.tim_ct_b = 0x10;
        mfp.active_edge |= 8;
        mfp.tim_ct_b = 0;
        mfp.tim_dt_b = 0xf0;
        mfp.tim_ct_b = 8;
        while (mfp.tim_dt_b > 1)        /* TOS does it this way, don't ask why */
                ;
        new = mfp.tim_dt_b;
        do {
                udelay(LINE_DELAY);
                old = new;
                new = mfp.tim_dt_b;
        } while (old != new);
        mfp.tim_ct_b = 0x10;
        udelay(SYNC_DELAY);

        if (atari_switches & ATARI_SWITCH_OVSC_IKBD)
                acia.key_ctrl = ACIA_DIV64 | ACIA_D8N1S | ACIA_RHTID | ACIA_RIE;
        if (atari_switches & ATARI_SWITCH_OVSC_MIDI)
                acia.mid_ctrl = ACIA_DIV16 | ACIA_D8N1S | ACIA_RHTID;
        if (atari_switches & (ATARI_SWITCH_OVSC_SND6|ATARI_SWITCH_OVSC_SND7)) {
                sound_ym.rd_data_reg_sel = 14;
                sound_ym.wd_data = sound_ym.rd_data_reg_sel |
                                   ((atari_switches & ATARI_SWITCH_OVSC_SND6) ? 0x40:0) |
                                   ((atari_switches & ATARI_SWITCH_OVSC_SND7) ? 0x80:0);
        }
        local_irq_restore(flags);
}

/* ------------------- External Video ---------------------- */

#ifdef ATAFB_EXT

static int ext_encode_fix(struct fb_fix_screeninfo *fix, struct atafb_par *par)
{
        strcpy(fix->id, "Unknown Extern");
        fix->smem_start = (unsigned long)external_addr;
        fix->smem_len = PAGE_ALIGN(external_len);
        if (external_depth == 1) {
                fix->type = FB_TYPE_PACKED_PIXELS;
                /* The letters 'n' and 'i' in the "atavideo=external:" stand
                 * for "normal" and "inverted", rsp., in the monochrome case */
                fix->visual =
                        (external_pmode == FB_TYPE_INTERLEAVED_PLANES ||
                         external_pmode == FB_TYPE_PACKED_PIXELS) ?
                                FB_VISUAL_MONO10 : FB_VISUAL_MONO01;
        } else {
                /* Use STATIC if we don't know how to access color registers */
                int visual = external_vgaiobase ?
                                         FB_VISUAL_PSEUDOCOLOR :
                                         FB_VISUAL_STATIC_PSEUDOCOLOR;
                switch (external_pmode) {
                case -1:                /* truecolor */
                        fix->type = FB_TYPE_PACKED_PIXELS;
                        fix->visual = FB_VISUAL_TRUECOLOR;
                        break;
                case FB_TYPE_PACKED_PIXELS:
                        fix->type = FB_TYPE_PACKED_PIXELS;
                        fix->visual = visual;
                        break;
                case FB_TYPE_PLANES:
                        fix->type = FB_TYPE_PLANES;
                        fix->visual = visual;
                        break;
                case FB_TYPE_INTERLEAVED_PLANES:
                        fix->type = FB_TYPE_INTERLEAVED_PLANES;
                        fix->type_aux = 2;
                        fix->visual = visual;
                        break;
                }
        }
        fix->xpanstep = 0;
        fix->ypanstep = 0;
        fix->ywrapstep = 0;
        fix->line_length = 0;
        return 0;
}

static int ext_decode_var(struct fb_var_screeninfo *var, struct atafb_par *par)
{
        struct fb_var_screeninfo *myvar = &atafb_predefined[0];

        if (var->bits_per_pixel > myvar->bits_per_pixel ||
            var->xres > myvar->xres ||
            var->xres_virtual > myvar->xres_virtual ||
            var->yres > myvar->yres ||
            var->xoffset > 0 ||
            var->yoffset > 0)
                return -EINVAL;
        return 0;
}

static int ext_encode_var(struct fb_var_screeninfo *var, struct atafb_par *par)
{
        memset(var, 0, sizeof(struct fb_var_screeninfo));
        var->red.offset = 0;
        var->red.length = (external_pmode == -1) ? external_depth / 3 :
                        (external_vgaiobase ? external_bitspercol : 0);
        var->red.msb_right = 0;
        var->grayscale = 0;

        var->pixclock = 31041;
        var->left_margin = 120;         /* these are surely incorrect */
        var->right_margin = 100;
        var->upper_margin = 8;
        var->lower_margin = 16;
        var->hsync_len = 140;
        var->vsync_len = 30;

        var->height = -1;
        var->width = -1;

        var->sync = 0;

        var->xres = external_xres;
        var->yres = external_yres;
        var->xres_virtual = external_xres_virtual;
        var->bits_per_pixel = external_depth;

        var->blue = var->green = var->red;
        var->transp.offset = 0;
        var->transp.length = 0;
        var->transp.msb_right = 0;
        var->yres_virtual = var->yres;
        var->xoffset = 0;
        var->yoffset = 0;
        var->nonstd = 0;
        var->activate = 0;
        var->vmode = FB_VMODE_NONINTERLACED;
        return 0;
}

static void ext_get_par(struct atafb_par *par)
{
        par->screen_base = external_addr;
}

static void ext_set_par(struct atafb_par *par)
{
}

#define OUTB(port,val) \
        *((unsigned volatile char *) ((port)+external_vgaiobase)) = (val)
#define INB(port) \
        (*((unsigned volatile char *) ((port)+external_vgaiobase)))
#define DACDelay                                \
        do {                                    \
                unsigned char tmp = INB(0x3da); \
                tmp = INB(0x3da);                       \
        } while (0)

static int ext_setcolreg(unsigned int regno, unsigned int red,
                         unsigned int green, unsigned int blue,
                         unsigned int transp, struct fb_info *info)
{
        unsigned char colmask = (1 << external_bitspercol) - 1;

        if (!external_vgaiobase)
                return 1;

        switch (external_card_type) {
        case IS_VGA:
                OUTB(0x3c8, regno);
                DACDelay;
                OUTB(0x3c9, red & colmask);
                DACDelay;
                OUTB(0x3c9, green & colmask);
                DACDelay;
                OUTB(0x3c9, blue & colmask);
                DACDelay;
                return 0;

        case IS_MV300:
                OUTB((MV300_reg[regno] << 2) + 1, red);
                OUTB((MV300_reg[regno] << 2) + 1, green);
                OUTB((MV300_reg[regno] << 2) + 1, blue);
                return 0;

        default:
                return 1;
        }
}

static int ext_detect(void)
{
        struct fb_var_screeninfo *myvar = &atafb_predefined[0];
        struct atafb_par dummy_par;

        myvar->xres = external_xres;
        myvar->xres_virtual = external_xres_virtual;
        myvar->yres = external_yres;
        myvar->bits_per_pixel = external_depth;
        ext_encode_var(myvar, &dummy_par);
        return 1;
}

#endif /* ATAFB_EXT */

/* ------ This is the same for most hardware types -------- */

static void set_screen_base(void *s_base)
{
        unsigned long addr;

        addr = virt_to_phys(s_base);
        /* Setup Screen Memory */
        shifter.bas_hi = (unsigned char)((addr & 0xff0000) >> 16);
        shifter.bas_md = (unsigned char)((addr & 0x00ff00) >> 8);
        shifter.bas_lo = (unsigned char)(addr & 0x0000ff);
}

static int pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
{
        struct atafb_par *par = (struct atafb_par *)info->par;

        if (!fbhw->set_screen_base ||
            (!ATARIHW_PRESENT(EXTD_SHIFTER) && var->xoffset))
                return -EINVAL;
        var->xoffset = up(var->xoffset, 16);
        par->screen_base = screen_base +
                (var->yoffset * info->var.xres_virtual + var->xoffset)
                * info->var.bits_per_pixel / 8;
        fbhw->set_screen_base(par->screen_base);
        return 0;
}

/* ------------ Interfaces to hardware functions ------------ */

#ifdef ATAFB_TT
static struct fb_hwswitch tt_switch = {
        .detect         = tt_detect,
        .encode_fix     = tt_encode_fix,
        .decode_var     = tt_decode_var,
        .encode_var     = tt_encode_var,
        .get_par        = tt_get_par,
        .set_par        = tt_set_par,
        .set_screen_base = set_screen_base,
        .pan_display    = pan_display,
};
#endif

#ifdef ATAFB_FALCON
static struct fb_hwswitch falcon_switch = {
        .detect         = falcon_detect,
        .encode_fix     = falcon_encode_fix,
        .decode_var     = falcon_decode_var,
        .encode_var     = falcon_encode_var,
        .get_par        = falcon_get_par,
        .set_par        = falcon_set_par,
        .set_screen_base = set_screen_base,
        .blank          = falcon_blank,
        .pan_display    = falcon_pan_display,
};
#endif

#ifdef ATAFB_STE
static struct fb_hwswitch st_switch = {
        .detect         = stste_detect,
        .encode_fix     = stste_encode_fix,
        .decode_var     = stste_decode_var,
        .encode_var     = stste_encode_var,
        .get_par        = stste_get_par,
        .set_par        = stste_set_par,
        .set_screen_base = stste_set_screen_base,
        .pan_display    = pan_display
};
#endif

#ifdef ATAFB_EXT
static struct fb_hwswitch ext_switch = {
        .detect         = ext_detect,
        .encode_fix     = ext_encode_fix,
        .decode_var     = ext_decode_var,
        .encode_var     = ext_encode_var,
        .get_par        = ext_get_par,
        .set_par        = ext_set_par,
};
#endif

static void ata_get_par(struct atafb_par *par)
{
        if (current_par_valid)
                *par = current_par;
        else
                fbhw->get_par(par);
}

static void ata_set_par(struct atafb_par *par)
{
        fbhw->set_par(par);
        current_par = *par;
        current_par_valid = 1;
}


/* =========================================================== */
/* ============== Hardware Independent Functions ============= */
/* =========================================================== */

/* used for hardware scrolling */

static int do_fb_set_var(struct fb_var_screeninfo *var, int isactive)
{
        int err, activate;
        struct atafb_par par;

        err = fbhw->decode_var(var, &par);
        if (err)
                return err;
        activate = var->activate;
        if (((var->activate & FB_ACTIVATE_MASK) == FB_ACTIVATE_NOW) && isactive)
                ata_set_par(&par);
        fbhw->encode_var(var, &par);
        var->activate = activate;
        return 0;
}

static int atafb_get_fix(struct fb_fix_screeninfo *fix, struct fb_info *info)
{
        struct atafb_par par;
        int err;
        // Get fix directly (case con == -1 before)??
        err = fbhw->decode_var(&info->var, &par);
        if (err)
                return err;
        memset(fix, 0, sizeof(struct fb_fix_screeninfo));
        return fbhw->encode_fix(fix, &par);
}

static int atafb_get_var(struct fb_var_screeninfo *var, struct fb_info *info)
{
        struct atafb_par par;

        ata_get_par(&par);
        fbhw->encode_var(var, &par);

        return 0;
}

// No longer called by fbcon!
// Still called by set_var internally

static void atafb_set_disp(struct fb_info *info)
{
        atafb_get_var(&info->var, info);
        atafb_get_fix(&info->fix, info);

        info->screen_base = (void *)info->fix.smem_start;

        switch (info->fix.type) {
        case FB_TYPE_INTERLEAVED_PLANES:
                switch (info->var.bits_per_pixel) {
                case 2:
                        // display->dispsw = &fbcon_iplan2p2;
                        break;
                case 4:
                        // display->dispsw = &fbcon_iplan2p4;
                        break;
                case 8:
                        // display->dispsw = &fbcon_iplan2p8;
                        break;
                }
                break;
        case FB_TYPE_PACKED_PIXELS:
                switch (info->var.bits_per_pixel) {
#ifdef FBCON_HAS_MFB
                case 1:
                        // display->dispsw = &fbcon_mfb;
                        break;
#endif
#ifdef FBCON_HAS_CFB8
                case 8:
                        // display->dispsw = &fbcon_cfb8;
                        break;
#endif
#ifdef FBCON_HAS_CFB16
                case 16:
                        // display->dispsw = &fbcon_cfb16;
                        // display->dispsw_data = fbcon_cfb16_cmap;
                        break;
#endif
                }
                break;
        }
}

static int atafb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
                           u_int transp, struct fb_info *info)
{
        red >>= 8;
        green >>= 8;
        blue >>= 8;

        return info->fbops->fb_setcolreg(regno, red, green, blue, transp, info);
}

static int
atafb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
{
        int xoffset = var->xoffset;
        int yoffset = var->yoffset;
        int err;

        if (var->vmode & FB_VMODE_YWRAP) {
                if (yoffset < 0 || yoffset >= info->var.yres_virtual || xoffset)
                        return -EINVAL;
        } else {
                if (xoffset + info->var.xres > info->var.xres_virtual ||
                    yoffset + info->var.yres > info->var.yres_virtual)
                        return -EINVAL;
        }

        if (fbhw->pan_display) {
                err = fbhw->pan_display(var, info);
                if (err)
                        return err;
        } else
                return -EINVAL;

        info->var.xoffset = xoffset;
        info->var.yoffset = yoffset;

        if (var->vmode & FB_VMODE_YWRAP)
                info->var.vmode |= FB_VMODE_YWRAP;
        else
                info->var.vmode &= ~FB_VMODE_YWRAP;

        return 0;
}

/*
 * generic drawing routines; imageblit needs updating for image depth > 1
 */

#if BITS_PER_LONG == 32
#define BYTES_PER_LONG  4
#define SHIFT_PER_LONG  5
#elif BITS_PER_LONG == 64
#define BYTES_PER_LONG  8
#define SHIFT_PER_LONG  6
#else
#define Please update me
#endif


static void atafb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
{
        struct atafb_par *par = (struct atafb_par *)info->par;
        int x2, y2;
        u32 width, height;

        if (!rect->width || !rect->height)
                return;

        /*
         * We could use hardware clipping but on many cards you get around
         * hardware clipping by writing to framebuffer directly.
         * */
        x2 = rect->dx + rect->width;
        y2 = rect->dy + rect->height;
        x2 = x2 < info->var.xres_virtual ? x2 : info->var.xres_virtual;
        y2 = y2 < info->var.yres_virtual ? y2 : info->var.yres_virtual;
        width = x2 - rect->dx;
        height = y2 - rect->dy;

        if (info->var.bits_per_pixel == 1)
                atafb_mfb_fillrect(info, par->next_line, rect->color,
                                   rect->dy, rect->dx, height, width);
        else if (info->var.bits_per_pixel == 2)
                atafb_iplan2p2_fillrect(info, par->next_line, rect->color,
                                        rect->dy, rect->dx, height, width);
        else if (info->var.bits_per_pixel == 4)
                atafb_iplan2p4_fillrect(info, par->next_line, rect->color,
                                        rect->dy, rect->dx, height, width);
        else
                atafb_iplan2p8_fillrect(info, par->next_line, rect->color,
                                        rect->dy, rect->dx, height, width);

        return;
}

static void atafb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
{
        struct atafb_par *par = (struct atafb_par *)info->par;
        int x2, y2;
        u32 dx, dy, sx, sy, width, height;
        int rev_copy = 0;

        /* clip the destination */
        x2 = area->dx + area->width;
        y2 = area->dy + area->height;
        dx = area->dx > 0 ? area->dx : 0;
        dy = area->dy > 0 ? area->dy : 0;
        x2 = x2 < info->var.xres_virtual ? x2 : info->var.xres_virtual;
        y2 = y2 < info->var.yres_virtual ? y2 : info->var.yres_virtual;
        width = x2 - dx;
        height = y2 - dy;

        if (area->sx + dx < area->dx || area->sy + dy < area->dy)
                return;

        /* update sx,sy */
        sx = area->sx + (dx - area->dx);
        sy = area->sy + (dy - area->dy);

        /* the source must be completely inside the virtual screen */
        if (sx + width > info->var.xres_virtual ||
                        sy + height > info->var.yres_virtual)
                return;

        if (dy > sy || (dy == sy && dx > sx)) {
                dy += height;
                sy += height;
                rev_copy = 1;
        }

        if (info->var.bits_per_pixel == 1)
                atafb_mfb_copyarea(info, par->next_line, sy, sx, dy, dx, height, width);
        else if (info->var.bits_per_pixel == 2)
                atafb_iplan2p2_copyarea(info, par->next_line, sy, sx, dy, dx, height, width);
        else if (info->var.bits_per_pixel == 4)
                atafb_iplan2p4_copyarea(info, par->next_line, sy, sx, dy, dx, height, width);
        else
                atafb_iplan2p8_copyarea(info, par->next_line, sy, sx, dy, dx, height, width);

        return;
}

static void atafb_imageblit(struct fb_info *info, const struct fb_image *image)
{
        struct atafb_par *par = (struct atafb_par *)info->par;
        int x2, y2;
        unsigned long *dst;
        int dst_idx;
        const char *src;
        u32 dx, dy, width, height, pitch;

        /*
         * We could use hardware clipping but on many cards you get around
         * hardware clipping by writing to framebuffer directly like we are
         * doing here.
         */
        x2 = image->dx + image->width;
        y2 = image->dy + image->height;
        dx = image->dx;
        dy = image->dy;
        x2 = x2 < info->var.xres_virtual ? x2 : info->var.xres_virtual;
        y2 = y2 < info->var.yres_virtual ? y2 : info->var.yres_virtual;
        width = x2 - dx;
        height = y2 - dy;

        if (image->depth == 1) {
                // used for font data
                dst = (unsigned long *)
                        ((unsigned long)info->screen_base & ~(BYTES_PER_LONG - 1));
                dst_idx = ((unsigned long)info->screen_base & (BYTES_PER_LONG - 1)) * 8;
                dst_idx += dy * par->next_line * 8 + dx;
                src = image->data;
                pitch = (image->width + 7) / 8;
                while (height--) {

                        if (info->var.bits_per_pixel == 1)
                                atafb_mfb_linefill(info, par->next_line,
                                                   dy, dx, width, src,
                                                   image->bg_color, image->fg_color);
                        else if (info->var.bits_per_pixel == 2)
                                atafb_iplan2p2_linefill(info, par->next_line,
                                                        dy, dx, width, src,
                                                        image->bg_color, image->fg_color);
                        else if (info->var.bits_per_pixel == 4)
                                atafb_iplan2p4_linefill(info, par->next_line,
                                                        dy, dx, width, src,
                                                        image->bg_color, image->fg_color);
                        else
                                atafb_iplan2p8_linefill(info, par->next_line,
                                                        dy, dx, width, src,
                                                        image->bg_color, image->fg_color);
                        dy++;
                        src += pitch;
                }
        } else {
                // only used for logo; broken
                c2p(info->screen_base, image->data, dx, dy, width, height,
                    par->next_line, par->next_plane, image->width,
                    info->var.bits_per_pixel);
        }
}

static int
atafb_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
{
        switch (cmd) {
#ifdef FBCMD_GET_CURRENTPAR
        case FBCMD_GET_CURRENTPAR:
                if (copy_to_user((void *)arg, (void *)&current_par,
                                 sizeof(struct atafb_par)))
                        return -EFAULT;
                return 0;
#endif
#ifdef FBCMD_SET_CURRENTPAR
        case FBCMD_SET_CURRENTPAR:
                if (copy_from_user((void *)&current_par, (void *)arg,
                                   sizeof(struct atafb_par)))
                        return -EFAULT;
                ata_set_par(&current_par);
                return 0;
#endif
        }
        return -EINVAL;
}

/* (un)blank/poweroff
 * 0 = unblank
 * 1 = blank
 * 2 = suspend vsync
 * 3 = suspend hsync
 * 4 = off
 */
static int atafb_blank(int blank, struct fb_info *info)
{
        unsigned short black[16];
        struct fb_cmap cmap;
        if (fbhw->blank && !fbhw->blank(blank))
                return 1;
        if (blank) {
                memset(black, 0, 16 * sizeof(unsigned short));
                cmap.red = black;
                cmap.green = black;
                cmap.blue = black;
                cmap.transp = NULL;
                cmap.start = 0;
                cmap.len = 16;
                fb_set_cmap(&cmap, info);
        }
#if 0
        else
                do_install_cmap(info);
#endif
        return 0;
}

        /*
         * New fbcon interface ...
         */

         /* check var by decoding var into hw par, rounding if necessary,
          * then encoding hw par back into new, validated var */
static int atafb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
{
        int err;
        struct atafb_par par;

        /* Validate wanted screen parameters */
        // if ((err = ata_decode_var(var, &par)))
        err = fbhw->decode_var(var, &par);
        if (err)
                return err;

        /* Encode (possibly rounded) screen parameters */
        fbhw->encode_var(var, &par);
        return 0;
}

        /* actually set hw par by decoding var, then setting hardware from
         * hw par just decoded */
static int atafb_set_par(struct fb_info *info)
{
        struct atafb_par *par = (struct atafb_par *)info->par;

        /* Decode wanted screen parameters */
        fbhw->decode_var(&info->var, par);
        fbhw->encode_fix(&info->fix, par);

        /* Set new videomode */
        ata_set_par(par);

        return 0;
}


static struct fb_ops atafb_ops = {
        .owner =        THIS_MODULE,
        .fb_check_var   = atafb_check_var,
        .fb_set_par     = atafb_set_par,
        .fb_setcolreg   = atafb_setcolreg,
        .fb_blank =     atafb_blank,
        .fb_pan_display = atafb_pan_display,
        .fb_fillrect    = atafb_fillrect,
        .fb_copyarea    = atafb_copyarea,
        .fb_imageblit   = atafb_imageblit,
        .fb_ioctl =     atafb_ioctl,
};

static void check_default_par(int detected_mode)
{
        char default_name[10];
        int i;
        struct fb_var_screeninfo var;
        unsigned long min_mem;

        /* First try the user supplied mode */
        if (default_par) {
                var = atafb_predefined[default_par - 1];
                var.activate = FB_ACTIVATE_TEST;
                if (do_fb_set_var(&var, 1))
                        default_par = 0;        /* failed */
        }
        /* Next is the autodetected one */
        if (!default_par) {
                var = atafb_predefined[detected_mode - 1]; /* autodetect */
                var.activate = FB_ACTIVATE_TEST;
                if (!do_fb_set_var(&var, 1))
                        default_par = detected_mode;
        }
        /* If that also failed, try some default modes... */
        if (!default_par) {
                /* try default1, default2... */
                for (i = 1; i < 10; i++) {
                        sprintf(default_name,"default%d", i);
                        default_par = get_video_mode(default_name);
                        if (!default_par)
                                panic("can't set default video mode");
                        var = atafb_predefined[default_par - 1];
                        var.activate = FB_ACTIVATE_TEST;
                        if (!do_fb_set_var(&var,1))
                                break;  /* ok */
                }
        }
        min_mem = var.xres_virtual * var.yres_virtual * var.bits_per_pixel / 8;
        if (default_mem_req < min_mem)
                default_mem_req = min_mem;
}

#ifdef ATAFB_EXT
static void __init atafb_setup_ext(char *spec)
{
        int xres, xres_virtual, yres, depth, planes;
        unsigned long addr, len;
        char *p;

        /* Format is: <xres>;<yres>;<depth>;<plane organ.>;
         *            <screen mem addr>
         *            [;<screen mem length>[;<vgaiobase>[;<bits-per-col>[;<colorreg-type>
         *            [;<xres-virtual>]]]]]
         *
         * 09/23/97     Juergen
         * <xres_virtual>:      hardware's x-resolution (f.e. ProMST)
         *
         * Even xres_virtual is available, we neither support panning nor hw-scrolling!
         */
        p = strsep(&spec, ";");
        if (!p || !*p)
                return;
        xres_virtual = xres = simple_strtoul(p, NULL, 10);
        if (xres <= 0)
                return;

        p = strsep(&spec, ";");
        if (!p || !*p)
                return;
        yres = simple_strtoul(p, NULL, 10);
        if (yres <= 0)
                return;

        p = strsep(&spec, ";");
        if (!p || !*p)
                return;
        depth = simple_strtoul(p, NULL, 10);
        if (depth != 1 && depth != 2 && depth != 4 && depth != 8 &&
            depth != 16 && depth != 24)
                return;

        p = strsep(&spec, ";");
        if (!p || !*p)
                return;
        if (*p == 'i')
                planes = FB_TYPE_INTERLEAVED_PLANES;
        else if (*p == 'p')
                planes = FB_TYPE_PACKED_PIXELS;
        else if (*p == 'n')
                planes = FB_TYPE_PLANES;
        else if (*p == 't')
                planes = -1;            /* true color */
        else
                return;

        p = strsep(&spec, ";");
        if (!p || !*p)
                return;
        addr = simple_strtoul(p, NULL, 0);

        p = strsep(&spec, ";");
        if (!p || !*p)
                len = xres * yres * depth / 8;
        else
                len = simple_strtoul(p, NULL, 0);

        p = strsep(&spec, ";");
        if (p && *p)
                external_vgaiobase = simple_strtoul(p, NULL, 0);

        p = strsep(&spec, ";");
        if (p && *p) {
                external_bitspercol = simple_strtoul(p, NULL, 0);
                if (external_bitspercol > 8)
                        external_bitspercol = 8;
                else if (external_bitspercol < 1)
                        external_bitspercol = 1;
        }

        p = strsep(&spec, ";");
        if (p && *p) {
                if (!strcmp(p, "vga"))
                        external_card_type = IS_VGA;
                if (!strcmp(p, "mv300"))
                        external_card_type = IS_MV300;
        }

        p = strsep(&spec, ";");
        if (p && *p) {
                xres_virtual = simple_strtoul(p, NULL, 10);
                if (xres_virtual < xres)
                        xres_virtual = xres;
                if (xres_virtual * yres * depth / 8 > len)
                        len = xres_virtual * yres * depth / 8;
        }

        external_xres = xres;
        external_xres_virtual = xres_virtual;
        external_yres = yres;
        external_depth = depth;
        external_pmode = planes;
        external_addr = (void *)addr;
        external_len = len;

        if (external_card_type == IS_MV300) {
                switch (external_depth) {
                case 1:
                        MV300_reg = MV300_reg_1bit;
                        break;
                case 4:
                        MV300_reg = MV300_reg_4bit;
                        break;
                case 8:
                        MV300_reg = MV300_reg_8bit;
                        break;
                }
        }
}
#endif /* ATAFB_EXT */

static void __init atafb_setup_int(char *spec)
{
        /* Format to config extended internal video hardware like OverScan:
         * "internal:<xres>;<yres>;<xres_max>;<yres_max>;<offset>"
         * Explanation:
         * <xres>: x-resolution
         * <yres>: y-resolution
         * The following are only needed if you have an overscan which
         * needs a black border:
         * <xres_max>: max. length of a line in pixels your OverScan hardware would allow
         * <yres_max>: max. number of lines your OverScan hardware would allow
         * <offset>: Offset from physical beginning to visible beginning
         *        of screen in bytes
         */
        int xres;
        char *p;

        if (!(p = strsep(&spec, ";")) || !*p)
                return;
        xres = simple_strtoul(p, NULL, 10);
        if (!(p = strsep(&spec, ";")) || !*p)
                return;
        sttt_xres = xres;
        tt_yres = st_yres = simple_strtoul(p, NULL, 10);
        if ((p = strsep(&spec, ";")) && *p)
                sttt_xres_virtual = simple_strtoul(p, NULL, 10);
        if ((p = strsep(&spec, ";")) && *p)
                sttt_yres_virtual = simple_strtoul(p, NULL, 0);
        if ((p = strsep(&spec, ";")) && *p)
                ovsc_offset = simple_strtoul(p, NULL, 0);

        if (ovsc_offset || (sttt_yres_virtual != st_yres))
                use_hwscroll = 0;
}

#ifdef ATAFB_FALCON
static void __init atafb_setup_mcap(char *spec)
{
        char *p;
        int vmin, vmax, hmin, hmax;

        /* Format for monitor capabilities is: <Vmin>;<Vmax>;<Hmin>;<Hmax>
         * <V*> vertical freq. in Hz
         * <H*> horizontal freq. in kHz
         */
        if (!(p = strsep(&spec, ";")) || !*p)
                return;
        vmin = simple_strtoul(p, NULL, 10);
        if (vmin <= 0)
                return;
        if (!(p = strsep(&spec, ";")) || !*p)
                return;
        vmax = simple_strtoul(p, NULL, 10);
        if (vmax <= 0 || vmax <= vmin)
                return;
        if (!(p = strsep(&spec, ";")) || !*p)
                return;
        hmin = 1000 * simple_strtoul(p, NULL, 10);
        if (hmin <= 0)
                return;
        if (!(p = strsep(&spec, "")) || !*p)
                return;
        hmax = 1000 * simple_strtoul(p, NULL, 10);
        if (hmax <= 0 || hmax <= hmin)
                return;

        fb_info.monspecs.vfmin = vmin;
        fb_info.monspecs.vfmax = vmax;
        fb_info.monspecs.hfmin = hmin;
        fb_info.monspecs.hfmax = hmax;
}
#endif /* ATAFB_FALCON */

static void __init atafb_setup_user(char *spec)
{
        /* Format of user defined video mode is: <xres>;<yres>;<depth>
         */
        char *p;
        int xres, yres, depth, temp;

        p = strsep(&spec, ";");
        if (!p || !*p)
                return;
        xres = simple_strtoul(p, NULL, 10);
        p = strsep(&spec, ";");
        if (!p || !*p)
                return;
        yres = simple_strtoul(p, NULL, 10);
        p = strsep(&spec, "");
        if (!p || !*p)
                return;
        depth = simple_strtoul(p, NULL, 10);
        temp = get_video_mode("user0");
        if (temp) {
                default_par = temp;
                atafb_predefined[default_par - 1].xres = xres;
                atafb_predefined[default_par - 1].yres = yres;
                atafb_predefined[default_par - 1].bits_per_pixel = depth;
        }
}

int __init atafb_setup(char *options)
{
        char *this_opt;
        int temp;

        if (!options || !*options)
                return 0;

        while ((this_opt = strsep(&options, ",")) != NULL) {
                if (!*this_opt)
                        continue;
                if ((temp = get_video_mode(this_opt))) {
                        default_par = temp;
                        mode_option = this_opt;
                } else if (!strcmp(this_opt, "inverse"))
                        inverse = 1;
                else if (!strncmp(this_opt, "hwscroll_", 9)) {
                        hwscroll = simple_strtoul(this_opt + 9, NULL, 10);
                        if (hwscroll < 0)
                                hwscroll = 0;
                        if (hwscroll > 200)
                                hwscroll = 200;
                }
#ifdef ATAFB_EXT
                else if (!strcmp(this_opt, "mv300")) {
                        external_bitspercol = 8;
                        external_card_type = IS_MV300;
                } else if (!strncmp(this_opt, "external:", 9))
                        atafb_setup_ext(this_opt + 9);
#endif
                else if (!strncmp(this_opt, "internal:", 9))
                        atafb_setup_int(this_opt + 9);
#ifdef ATAFB_FALCON
                else if (!strncmp(this_opt, "eclock:", 7)) {
                        fext.f = simple_strtoul(this_opt + 7, NULL, 10);
                        /* external pixelclock in kHz --> ps */
                        fext.t = 1000000000 / fext.f;
                        fext.f *= 1000;
                } else if (!strncmp(this_opt, "monitorcap:", 11))
                        atafb_setup_mcap(this_opt + 11);
#endif
                else if (!strcmp(this_opt, "keep"))
                        DontCalcRes = 1;
                else if (!strncmp(this_opt, "R", 1))
                        atafb_setup_user(this_opt + 1);
        }
        return 0;
}

int __init atafb_init(void)
{
        int pad;
        int detected_mode;
        unsigned int defmode = 0;
        unsigned long mem_req;

#ifndef MODULE
        char *option = NULL;

        if (fb_get_options("atafb", &option))
                return -ENODEV;
        atafb_setup(option);
#endif
        printk("atafb_init: start\n");

        if (!MACH_IS_ATARI)
                return -ENODEV;

        do {
#ifdef ATAFB_EXT
                if (external_addr) {
                        printk("atafb_init: initializing external hw\n");
                        fbhw = &ext_switch;
                        atafb_ops.fb_setcolreg = &ext_setcolreg;
                        defmode = DEFMODE_EXT;
                        break;
                }
#endif
#ifdef ATAFB_TT
                if (ATARIHW_PRESENT(TT_SHIFTER)) {
                        printk("atafb_init: initializing TT hw\n");
                        fbhw = &tt_switch;
                        atafb_ops.fb_setcolreg = &tt_setcolreg;
                        defmode = DEFMODE_TT;
                        break;
                }
#endif
#ifdef ATAFB_FALCON
                if (ATARIHW_PRESENT(VIDEL_SHIFTER)) {
                        printk("atafb_init: initializing Falcon hw\n");
                        fbhw = &falcon_switch;
                        atafb_ops.fb_setcolreg = &falcon_setcolreg;
                        request_irq(IRQ_AUTO_4, falcon_vbl_switcher, IRQ_TYPE_PRIO,
                                    "framebuffer/modeswitch", falcon_vbl_switcher);
                        defmode = DEFMODE_F30;
                        break;
                }
#endif
#ifdef ATAFB_STE
                if (ATARIHW_PRESENT(STND_SHIFTER) ||
                    ATARIHW_PRESENT(EXTD_SHIFTER)) {
                        printk("atafb_init: initializing ST/E hw\n");
                        fbhw = &st_switch;
                        atafb_ops.fb_setcolreg = &stste_setcolreg;
                        defmode = DEFMODE_STE;
                        break;
                }
                fbhw = &st_switch;
                atafb_ops.fb_setcolreg = &stste_setcolreg;
                printk("Cannot determine video hardware; defaulting to ST(e)\n");
#else /* ATAFB_STE */
                /* no default driver included */
                /* Nobody will ever see this message :-) */
                panic("Cannot initialize video hardware");
#endif
        } while (0);

        /* Multisync monitor capabilities */
        /* Atari-TOS defaults if no boot option present */
        if (fb_info.monspecs.hfmin == 0) {
                fb_info.monspecs.hfmin = 31000;
                fb_info.monspecs.hfmax = 32000;
                fb_info.monspecs.vfmin = 58;
                fb_info.monspecs.vfmax = 62;
        }

        detected_mode = fbhw->detect();
        check_default_par(detected_mode);
#ifdef ATAFB_EXT
        if (!external_addr) {
#endif /* ATAFB_EXT */
                mem_req = default_mem_req + ovsc_offset + ovsc_addlen;
                mem_req = PAGE_ALIGN(mem_req) + PAGE_SIZE;
                screen_base = atari_stram_alloc(mem_req, "atafb");
                if (!screen_base)
                        panic("Cannot allocate screen memory");
                memset(screen_base, 0, mem_req);
                pad = -(unsigned long)screen_base & (PAGE_SIZE - 1);
                screen_base += pad;
                real_screen_base = screen_base + ovsc_offset;
                screen_len = (mem_req - pad - ovsc_offset) & PAGE_MASK;
                st_ovsc_switch();
                if (CPU_IS_040_OR_060) {
                        /* On a '040+, the cache mode of video RAM must be set to
                         * write-through also for internal video hardware! */
                        cache_push(virt_to_phys(screen_base), screen_len);
                        kernel_set_cachemode(screen_base, screen_len,
                                             IOMAP_WRITETHROUGH);
                }
                printk("atafb: screen_base %p real_screen_base %p screen_len %d\n",
                        screen_base, real_screen_base, screen_len);
#ifdef ATAFB_EXT
        } else {
                /* Map the video memory (physical address given) to somewhere
                 * in the kernel address space.
                 */
                external_addr = ioremap_writethrough((unsigned long)external_addr,
                                                     external_len);
                if (external_vgaiobase)
                        external_vgaiobase =
                          (unsigned long)ioremap(external_vgaiobase, 0x10000);
                screen_base =
                real_screen_base = external_addr;
                screen_len = external_len & PAGE_MASK;
                memset (screen_base, 0, external_len);
        }
#endif /* ATAFB_EXT */

//      strcpy(fb_info.mode->name, "Atari Builtin ");
        fb_info.fbops = &atafb_ops;
        // try to set default (detected; requested) var
        do_fb_set_var(&atafb_predefined[default_par - 1], 1);
        // reads hw state into current par, which may not be sane yet
        ata_get_par(&current_par);
        fb_info.par = &current_par;
        // tries to read from HW which may not be initialized yet
        // so set sane var first, then call atafb_set_par
        atafb_get_var(&fb_info.var, &fb_info);
        fb_info.flags = FBINFO_FLAG_DEFAULT;

        if (!fb_find_mode(&fb_info.var, &fb_info, mode_option, atafb_modedb,
                          NUM_TOTAL_MODES, &atafb_modedb[defmode],
                          fb_info.var.bits_per_pixel)) {
                return -EINVAL;
        }

        fb_videomode_to_modelist(atafb_modedb, NUM_TOTAL_MODES,
                                 &fb_info.modelist);

        atafb_set_disp(&fb_info);

        fb_alloc_cmap(&(fb_info.cmap), 1 << fb_info.var.bits_per_pixel, 0);


        printk("Determined %dx%d, depth %d\n",
               fb_info.var.xres, fb_info.var.yres, fb_info.var.bits_per_pixel);
        if ((fb_info.var.xres != fb_info.var.xres_virtual) ||
            (fb_info.var.yres != fb_info.var.yres_virtual))
                printk("   virtual %dx%d\n", fb_info.var.xres_virtual,
                       fb_info.var.yres_virtual);

        if (register_framebuffer(&fb_info) < 0) {
#ifdef ATAFB_EXT
                if (external_addr) {
                        iounmap(external_addr);
                        external_addr = NULL;
                }
                if (external_vgaiobase) {
                        iounmap((void*)external_vgaiobase);
                        external_vgaiobase = 0;
                }
#endif
                return -EINVAL;
        }

        // FIXME: mode needs setting!
        //printk("fb%d: %s frame buffer device, using %dK of video memory\n",
        //       fb_info.node, fb_info.mode->name, screen_len>>10);
        printk("fb%d: frame buffer device, using %dK of video memory\n",
               fb_info.node, screen_len >> 10);

        /* TODO: This driver cannot be unloaded yet */
        return 0;
}

module_init(atafb_init);

#ifdef MODULE
MODULE_LICENSE("GPL");

int cleanup_module(void)
{
        unregister_framebuffer(&fb_info);
        return atafb_deinit();
}
#endif /* MODULE */