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cirrusfb.c

/*
 * drivers/video/cirrusfb.c - driver for Cirrus Logic chipsets
 *
 * Copyright 1999-2001 Jeff Garzik <jgarzik@pobox.com>
 *
 * Contributors (thanks, all!)
 *
 *    David Eger:
 *    Overhaul for Linux 2.6
 *
 *      Jeff Rugen:
 *      Major contributions;  Motorola PowerStack (PPC and PCI) support,
 *      GD54xx, 1280x1024 mode support, change MCLK based on VCLK.
 *
 *    Geert Uytterhoeven:
 *    Excellent code review.
 *
 *    Lars Hecking:
 *    Amiga updates and testing.
 *
 * Original cirrusfb author:  Frank Neumann
 *
 * Based on retz3fb.c and cirrusfb.c:
 *      Copyright (C) 1997 Jes Sorensen
 *      Copyright (C) 1996 Frank Neumann
 *
 ***************************************************************
 *
 * Format this code with GNU indent '-kr -i8 -pcs' options.
 *
 * 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.
 *
 */

#define CIRRUSFB_VERSION "2.0-pre2"

#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/fb.h>
#include <linux/init.h>
#include <asm/pgtable.h>

#ifdef CONFIG_ZORRO
#include <linux/zorro.h>
#endif
#ifdef CONFIG_PCI
#include <linux/pci.h>
#endif
#ifdef CONFIG_AMIGA
#include <asm/amigahw.h>
#endif
#ifdef CONFIG_PPC_PREP
#include <asm/machdep.h>
#define isPReP machine_is(prep)
#else
#define isPReP 0
#endif

#include <video/vga.h>
#include <video/cirrus.h>

/*****************************************************************
 *
 * debugging and utility macros
 *
 */

/* enable debug output? */
/* #define CIRRUSFB_DEBUG 1 */

/* disable runtime assertions? */
/* #define CIRRUSFB_NDEBUG */

/* debug output */
#ifdef CIRRUSFB_DEBUG
#define DPRINTK(fmt, args...) \
      printk(KERN_DEBUG "%s: " fmt, __FUNCTION__ , ## args)
#else
#define DPRINTK(fmt, args...)
#endif

/* debugging assertions */
#ifndef CIRRUSFB_NDEBUG
#define assert(expr) \
      if (!(expr)) { \
            printk("Assertion failed! %s,%s,%s,line=%d\n", \
            #expr, __FILE__, __FUNCTION__, __LINE__); \
      }
#else
#define assert(expr)
#endif

#define MB_ (1024 * 1024)

/*****************************************************************
 *
 * chipset information
 *
 */

/* board types */
enum cirrus_board {
      BT_NONE = 0,
      BT_SD64,
      BT_PICCOLO,
      BT_PICASSO,
      BT_SPECTRUM,
      BT_PICASSO4,      /* GD5446 */
      BT_ALPINE,  /* GD543x/4x */
      BT_GD5480,
      BT_LAGUNA,  /* GD546x */
};

/*
 * per-board-type information, used for enumerating and abstracting
 * chip-specific information
 * NOTE: MUST be in the same order as enum cirrus_board in order to
 * use direct indexing on this array
 * NOTE: '__initdata' cannot be used as some of this info
 * is required at runtime.  Maybe separate into an init-only and
 * a run-time table?
 */
static const struct cirrusfb_board_info_rec {
      char *name;       /* ASCII name of chipset */
      long maxclock[5];       /* maximum video clock */
      /* for  1/4bpp, 8bpp 15/16bpp, 24bpp, 32bpp - numbers from xorg code */
      bool init_sr07 : 1; /* init SR07 during init_vgachip() */
      bool init_sr1f : 1; /* write SR1F during init_vgachip() */
      /* construct bit 19 of screen start address */
      bool scrn_start_bit19 : 1;

      /* initial SR07 value, then for each mode */
      unsigned char sr07;
      unsigned char sr07_1bpp;
      unsigned char sr07_1bpp_mux;
      unsigned char sr07_8bpp;
      unsigned char sr07_8bpp_mux;

      unsigned char sr1f;     /* SR1F VGA initial register value */
} cirrusfb_board_info[] = {
      [BT_SD64] = {
            .name             = "CL SD64",
            .maxclock         = {
                  /* guess */
                  /* the SD64/P4 have a higher max. videoclock */
                  140000, 140000, 140000, 140000, 140000,
            },
            .init_sr07        = true,
            .init_sr1f        = true,
            .scrn_start_bit19 = true,
            .sr07             = 0xF0,
            .sr07_1bpp        = 0xF0,
            .sr07_8bpp        = 0xF1,
            .sr1f             = 0x20
      },
      [BT_PICCOLO] = {
            .name             = "CL Piccolo",
            .maxclock         = {
                  /* guess */
                  90000, 90000, 90000, 90000, 90000
            },
            .init_sr07        = true,
            .init_sr1f        = true,
            .scrn_start_bit19 = false,
            .sr07             = 0x80,
            .sr07_1bpp        = 0x80,
            .sr07_8bpp        = 0x81,
            .sr1f             = 0x22
      },
      [BT_PICASSO] = {
            .name             = "CL Picasso",
            .maxclock         = {
                  /* guess */
                  90000, 90000, 90000, 90000, 90000
            },
            .init_sr07        = true,
            .init_sr1f        = true,
            .scrn_start_bit19 = false,
            .sr07             = 0x20,
            .sr07_1bpp        = 0x20,
            .sr07_8bpp        = 0x21,
            .sr1f             = 0x22
      },
      [BT_SPECTRUM] = {
            .name             = "CL Spectrum",
            .maxclock         = {
                  /* guess */
                  90000, 90000, 90000, 90000, 90000
            },
            .init_sr07        = true,
            .init_sr1f        = true,
            .scrn_start_bit19 = false,
            .sr07             = 0x80,
            .sr07_1bpp        = 0x80,
            .sr07_8bpp        = 0x81,
            .sr1f             = 0x22
      },
      [BT_PICASSO4] = {
            .name             = "CL Picasso4",
            .maxclock         = {
                  135100, 135100, 85500, 85500, 0
            },
            .init_sr07        = true,
            .init_sr1f        = false,
            .scrn_start_bit19 = true,
            .sr07             = 0x20,
            .sr07_1bpp        = 0x20,
            .sr07_8bpp        = 0x21,
            .sr1f             = 0
      },
      [BT_ALPINE] = {
            .name             = "CL Alpine",
            .maxclock         = {
                  /* for the GD5430.  GD5446 can do more... */
                  85500, 85500, 50000, 28500, 0
            },
            .init_sr07        = true,
            .init_sr1f        = true,
            .scrn_start_bit19 = true,
            .sr07             = 0xA0,
            .sr07_1bpp        = 0xA1,
            .sr07_1bpp_mux          = 0xA7,
            .sr07_8bpp        = 0xA1,
            .sr07_8bpp_mux          = 0xA7,
            .sr1f             = 0x1C
      },
      [BT_GD5480] = {
            .name             = "CL GD5480",
            .maxclock         = {
                  135100, 200000, 200000, 135100, 135100
            },
            .init_sr07        = true,
            .init_sr1f        = true,
            .scrn_start_bit19 = true,
            .sr07             = 0x10,
            .sr07_1bpp        = 0x11,
            .sr07_8bpp        = 0x11,
            .sr1f             = 0x1C
      },
      [BT_LAGUNA] = {
            .name             = "CL Laguna",
            .maxclock         = {
                  /* guess */
                  135100, 135100, 135100, 135100, 135100,
            },
            .init_sr07        = false,
            .init_sr1f        = false,
            .scrn_start_bit19 = true,
      }
};

#ifdef CONFIG_PCI
#define CHIP(id, btype) \
      { PCI_VENDOR_ID_CIRRUS, id, PCI_ANY_ID, PCI_ANY_ID, 0, 0, (btype) }

static struct pci_device_id cirrusfb_pci_table[] = {
      CHIP(PCI_DEVICE_ID_CIRRUS_5436, BT_ALPINE),
      CHIP(PCI_DEVICE_ID_CIRRUS_5434_8, BT_ALPINE),
      CHIP(PCI_DEVICE_ID_CIRRUS_5434_4, BT_ALPINE),
      CHIP(PCI_DEVICE_ID_CIRRUS_5430, BT_ALPINE), /* GD-5440 is same id */
      CHIP(PCI_DEVICE_ID_CIRRUS_7543, BT_ALPINE),
      CHIP(PCI_DEVICE_ID_CIRRUS_7548, BT_ALPINE),
      CHIP(PCI_DEVICE_ID_CIRRUS_5480, BT_GD5480), /* MacPicasso likely */
      CHIP(PCI_DEVICE_ID_CIRRUS_5446, BT_PICASSO4), /* Picasso 4 is 5446 */
      CHIP(PCI_DEVICE_ID_CIRRUS_5462, BT_LAGUNA), /* CL Laguna */
      CHIP(PCI_DEVICE_ID_CIRRUS_5464, BT_LAGUNA), /* CL Laguna 3D */
      CHIP(PCI_DEVICE_ID_CIRRUS_5465, BT_LAGUNA), /* CL Laguna 3DA*/
      { 0, }
};
MODULE_DEVICE_TABLE(pci, cirrusfb_pci_table);
#undef CHIP
#endif /* CONFIG_PCI */

#ifdef CONFIG_ZORRO
static const struct zorro_device_id cirrusfb_zorro_table[] = {
      {
            .id         = ZORRO_PROD_HELFRICH_SD64_RAM,
            .driver_data      = BT_SD64,
      }, {
            .id         = ZORRO_PROD_HELFRICH_PICCOLO_RAM,
            .driver_data      = BT_PICCOLO,
      }, {
            .id   = ZORRO_PROD_VILLAGE_TRONIC_PICASSO_II_II_PLUS_RAM,
            .driver_data      = BT_PICASSO,
      }, {
            .id         = ZORRO_PROD_GVP_EGS_28_24_SPECTRUM_RAM,
            .driver_data      = BT_SPECTRUM,
      }, {
            .id         = ZORRO_PROD_VILLAGE_TRONIC_PICASSO_IV_Z3,
            .driver_data      = BT_PICASSO4,
      },
      { 0 }
};

static const struct {
      zorro_id id2;
      unsigned long size;
} cirrusfb_zorro_table2[] = {
      [BT_SD64] = {
            .id2  = ZORRO_PROD_HELFRICH_SD64_REG,
            .size = 0x400000
      },
      [BT_PICCOLO] = {
            .id2  = ZORRO_PROD_HELFRICH_PICCOLO_REG,
            .size = 0x200000
      },
      [BT_PICASSO] = {
            .id2  = ZORRO_PROD_VILLAGE_TRONIC_PICASSO_II_II_PLUS_REG,
            .size = 0x200000
      },
      [BT_SPECTRUM] = {
            .id2  = ZORRO_PROD_GVP_EGS_28_24_SPECTRUM_REG,
            .size = 0x200000
      },
      [BT_PICASSO4] = {
            .id2  = 0,
            .size = 0x400000
      }
};
#endif /* CONFIG_ZORRO */

struct cirrusfb_regs {
      long freq;
      long nom;
      long den;
      long div;
      long multiplexing;
      long mclk;
      long divMCLK;

      long HorizRes;          /* The x resolution in pixel */
      long HorizTotal;
      long HorizDispEnd;
      long HorizBlankStart;
      long HorizBlankEnd;
      long HorizSyncStart;
      long HorizSyncEnd;

      long VertRes;           /* the physical y resolution in scanlines */
      long VertTotal;
      long VertDispEnd;
      long VertSyncStart;
      long VertSyncEnd;
      long VertBlankStart;
      long VertBlankEnd;
};

#ifdef CIRRUSFB_DEBUG
enum cirrusfb_dbg_reg_class {
      CRT,
      SEQ
};
#endif            /* CIRRUSFB_DEBUG */

/* info about board */
struct cirrusfb_info {
      u8 __iomem *regbase;
      enum cirrus_board btype;
      unsigned char SFR;      /* Shadow of special function register */

      struct cirrusfb_regs currentmode;
      int blank_mode;

      u32   pseudo_palette[16];

#ifdef CONFIG_ZORRO
      struct zorro_dev *zdev;
#endif
#ifdef CONFIG_PCI
      struct pci_dev *pdev;
#endif
      void (*unmap)(struct fb_info *info);
};

static unsigned cirrusfb_def_mode = 1;
static int noaccel;

/*
 *    Predefined Video Modes
 */

static const struct {
      const char *name;
      struct fb_var_screeninfo var;
} cirrusfb_predefined[] = {
      {
            /* autodetect mode */
            .name = "Autodetect",
      }, {
            /* 640x480, 31.25 kHz, 60 Hz, 25 MHz PixClock */
            .name = "640x480",
            .var  = {
                  .xres       = 640,
                  .yres       = 480,
                  .xres_virtual     = 640,
                  .yres_virtual     = 480,
                  .bits_per_pixel   = 8,
                  .red        = { .length = 8 },
                  .green            = { .length = 8 },
                  .blue       = { .length = 8 },
                  .width            = -1,
                  .height           = -1,
                  .pixclock   = 40000,
                  .left_margin      = 48,
                  .right_margin     = 16,
                  .upper_margin     = 32,
                  .lower_margin     = 8,
                  .hsync_len  = 96,
                  .vsync_len  = 4,
                  .sync = FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
                  .vmode            = FB_VMODE_NONINTERLACED
             }
      }, {
            /* 800x600, 48 kHz, 76 Hz, 50 MHz PixClock */
            .name = "800x600",
            .var  = {
                  .xres       = 800,
                  .yres       = 600,
                  .xres_virtual     = 800,
                  .yres_virtual     = 600,
                  .bits_per_pixel   = 8,
                  .red        = { .length = 8 },
                  .green            = { .length = 8 },
                  .blue       = { .length = 8 },
                  .width            = -1,
                  .height           = -1,
                  .pixclock   = 20000,
                  .left_margin      = 128,
                  .right_margin     = 16,
                  .upper_margin     = 24,
                  .lower_margin     = 2,
                  .hsync_len  = 96,
                  .vsync_len  = 6,
                  .vmode            = FB_VMODE_NONINTERLACED
             }
      }, {
            /*
             * Modeline from XF86Config:
             * Mode "1024x768" 80  1024 1136 1340 1432  768 770 774 805
             */
            /* 1024x768, 55.8 kHz, 70 Hz, 80 MHz PixClock */
            .name = "1024x768",
            .var  = {
                  .xres       = 1024,
                  .yres       = 768,
                  .xres_virtual     = 1024,
                  .yres_virtual     = 768,
                  .bits_per_pixel   = 8,
                  .red        = { .length = 8 },
                  .green            = { .length = 8 },
                  .blue       = { .length = 8 },
                  .width            = -1,
                  .height           = -1,
                  .pixclock   = 12500,
                  .left_margin      = 144,
                  .right_margin     = 32,
                  .upper_margin     = 30,
                  .lower_margin     = 2,
                  .hsync_len  = 192,
                  .vsync_len  = 6,
                  .vmode            = FB_VMODE_NONINTERLACED
            }
      }
};

#define NUM_TOTAL_MODES    ARRAY_SIZE(cirrusfb_predefined)

/****************************************************************************/
/**** BEGIN PROTOTYPES ******************************************************/

/*--- Interface used by the world ------------------------------------------*/
static int cirrusfb_init(void);
#ifndef MODULE
static int cirrusfb_setup(char *options);
#endif

static int cirrusfb_open(struct fb_info *info, int user);
static int cirrusfb_release(struct fb_info *info, int user);
static int cirrusfb_setcolreg(unsigned regno, unsigned red, unsigned green,
                        unsigned blue, unsigned transp,
                        struct fb_info *info);
static int cirrusfb_check_var(struct fb_var_screeninfo *var,
                        struct fb_info *info);
static int cirrusfb_set_par(struct fb_info *info);
static int cirrusfb_pan_display(struct fb_var_screeninfo *var,
                        struct fb_info *info);
static int cirrusfb_blank(int blank_mode, struct fb_info *info);
static void cirrusfb_fillrect(struct fb_info *info,
                        const struct fb_fillrect *region);
static void cirrusfb_copyarea(struct fb_info *info,
                        const struct fb_copyarea *area);
static void cirrusfb_imageblit(struct fb_info *info,
                         const struct fb_image *image);

/* function table of the above functions */
static struct fb_ops cirrusfb_ops = {
      .owner            = THIS_MODULE,
      .fb_open    = cirrusfb_open,
      .fb_release = cirrusfb_release,
      .fb_setcolreg     = cirrusfb_setcolreg,
      .fb_check_var     = cirrusfb_check_var,
      .fb_set_par = cirrusfb_set_par,
      .fb_pan_display = cirrusfb_pan_display,
      .fb_blank   = cirrusfb_blank,
      .fb_fillrect      = cirrusfb_fillrect,
      .fb_copyarea      = cirrusfb_copyarea,
      .fb_imageblit     = cirrusfb_imageblit,
};

/*--- Hardware Specific Routines -------------------------------------------*/
static int cirrusfb_decode_var(const struct fb_var_screeninfo *var,
                        struct cirrusfb_regs *regs,
                        struct fb_info *info);
/*--- Internal routines ----------------------------------------------------*/
static void init_vgachip(struct fb_info *info);
static void switch_monitor(struct cirrusfb_info *cinfo, int on);
static void WGen(const struct cirrusfb_info *cinfo,
             int regnum, unsigned char val);
static unsigned char RGen(const struct cirrusfb_info *cinfo, int regnum);
static void AttrOn(const struct cirrusfb_info *cinfo);
static void WHDR(const struct cirrusfb_info *cinfo, unsigned char val);
static void WSFR(struct cirrusfb_info *cinfo, unsigned char val);
static void WSFR2(struct cirrusfb_info *cinfo, unsigned char val);
static void WClut(struct cirrusfb_info *cinfo, unsigned char regnum,
              unsigned char red, unsigned char green, unsigned char blue);
#if 0
static void RClut(struct cirrusfb_info *cinfo, unsigned char regnum,
              unsigned char *red, unsigned char *green,
              unsigned char *blue);
#endif
static void cirrusfb_WaitBLT(u8 __iomem *regbase);
static void cirrusfb_BitBLT(u8 __iomem *regbase, int bits_per_pixel,
                      u_short curx, u_short cury,
                      u_short destx, u_short desty,
                      u_short width, u_short height,
                      u_short line_length);
static void cirrusfb_RectFill(u8 __iomem *regbase, int bits_per_pixel,
                        u_short x, u_short y,
                        u_short width, u_short height,
                        u_char color, u_short line_length);

static void bestclock(long freq, long *best,
                  long *nom, long *den,
                  long *div, long maxfreq);

#ifdef CIRRUSFB_DEBUG
static void cirrusfb_dump(void);
static void cirrusfb_dbg_reg_dump(caddr_t regbase);
static void cirrusfb_dbg_print_regs(caddr_t regbase,
                            enum cirrusfb_dbg_reg_class reg_class, ...);
static void cirrusfb_dbg_print_byte(const char *name, unsigned char val);
#endif /* CIRRUSFB_DEBUG */

/*** END   PROTOTYPES ********************************************************/
/*****************************************************************************/
/*** BEGIN Interface Used by the World ***************************************/

static int opencount;

/*--- Open /dev/fbx ---------------------------------------------------------*/
static int cirrusfb_open(struct fb_info *info, int user)
{
      if (opencount++ == 0)
            switch_monitor(info->par, 1);
      return 0;
}

/*--- Close /dev/fbx --------------------------------------------------------*/
static int cirrusfb_release(struct fb_info *info, int user)
{
      if (--opencount == 0)
            switch_monitor(info->par, 0);
      return 0;
}

/**** END   Interface used by the World *************************************/
/****************************************************************************/
/**** BEGIN Hardware specific Routines **************************************/

/* Get a good MCLK value */
static long cirrusfb_get_mclk(long freq, int bpp, long *div)
{
      long mclk;

      assert(div != NULL);

      /* Calculate MCLK, in case VCLK is high enough to require > 50MHz.
       * Assume a 64-bit data path for now.  The formula is:
       * ((B * PCLK * 2)/W) * 1.2
       * B = bytes per pixel, PCLK = pixclock, W = data width in bytes */
      mclk = ((bpp / 8) * freq * 2) / 4;
      mclk = (mclk * 12) / 10;
      if (mclk < 50000)
            mclk = 50000;
      DPRINTK("Use MCLK of %ld kHz\n", mclk);

      /* Calculate value for SR1F.  Multiply by 2 so we can round up. */
      mclk = ((mclk * 16) / 14318);
      mclk = (mclk + 1) / 2;
      DPRINTK("Set SR1F[5:0] to 0x%lx\n", mclk);

      /* Determine if we should use MCLK instead of VCLK, and if so, what we
         * should divide it by to get VCLK */
      switch (freq) {
      case 24751 ... 25249:
            *div = 2;
            DPRINTK("Using VCLK = MCLK/2\n");
            break;
      case 49501 ... 50499:
            *div = 1;
            DPRINTK("Using VCLK = MCLK\n");
            break;
      default:
            *div = 0;
            break;
      }

      return mclk;
}

static int cirrusfb_check_var(struct fb_var_screeninfo *var,
                        struct fb_info *info)
{
      int nom, den;           /* translyting from pixels->bytes */
      int yres, i;
      static struct { int xres, yres; } modes[] =
      { { 1600, 1280 },
        { 1280, 1024 },
        { 1024, 768 },
        { 800, 600 },
        { 640, 480 },
        { -1, -1 } };

      switch (var->bits_per_pixel) {
      case 1:
            nom = 4;
            den = 8;
            break;            /* 8 pixel per byte, only 1/4th of mem usable */
      case 8:
      case 16:
      case 24:
      case 32:
            nom = var->bits_per_pixel / 8;
            den = 1;
            break;            /* 1 pixel == 1 byte */
      default:
            printk(KERN_ERR "cirrusfb: mode %dx%dx%d rejected..."
                  "color depth not supported.\n",
                  var->xres, var->yres, var->bits_per_pixel);
            DPRINTK("EXIT - EINVAL error\n");
            return -EINVAL;
      }

      if (var->xres * nom / den * var->yres > info->screen_size) {
            printk(KERN_ERR "cirrusfb: mode %dx%dx%d rejected..."
                  "resolution too high to fit into video memory!\n",
                  var->xres, var->yres, var->bits_per_pixel);
            DPRINTK("EXIT - EINVAL error\n");
            return -EINVAL;
      }

      /* use highest possible virtual resolution */
      if (var->xres_virtual == -1 &&
          var->yres_virtual == -1) {
            printk(KERN_INFO
                 "cirrusfb: using maximum available virtual resolution\n");
            for (i = 0; modes[i].xres != -1; i++) {
                  int size = modes[i].xres * nom / den * modes[i].yres;
                  if (size < info->screen_size / 2)
                        break;
            }
            if (modes[i].xres == -1) {
                  printk(KERN_ERR "cirrusfb: could not find a virtual "
                        "resolution that fits into video memory!!\n");
                  DPRINTK("EXIT - EINVAL error\n");
                  return -EINVAL;
            }
            var->xres_virtual = modes[i].xres;
            var->yres_virtual = modes[i].yres;

            printk(KERN_INFO "cirrusfb: virtual resolution set to "
                  "maximum of %dx%d\n", var->xres_virtual,
                  var->yres_virtual);
      }

      if (var->xres_virtual < var->xres)
            var->xres_virtual = var->xres;
      if (var->yres_virtual < var->yres)
            var->yres_virtual = var->yres;

      if (var->xoffset < 0)
            var->xoffset = 0;
      if (var->yoffset < 0)
            var->yoffset = 0;

      /* truncate xoffset and yoffset to maximum if too high */
      if (var->xoffset > var->xres_virtual - var->xres)
            var->xoffset = var->xres_virtual - var->xres - 1;
      if (var->yoffset > var->yres_virtual - var->yres)
            var->yoffset = var->yres_virtual - var->yres - 1;

      switch (var->bits_per_pixel) {
      case 1:
            var->red.offset = 0;
            var->red.length = 1;
            var->green = var->red;
            var->blue = var->red;
            break;

      case 8:
            var->red.offset = 0;
            var->red.length = 6;
            var->green = var->red;
            var->blue = var->red;
            break;

      case 16:
            if (isPReP) {
                  var->red.offset = 2;
                  var->green.offset = -3;
                  var->blue.offset = 8;
            } else {
                  var->red.offset = 10;
                  var->green.offset = 5;
                  var->blue.offset = 0;
            }
            var->red.length = 5;
            var->green.length = 5;
            var->blue.length = 5;
            break;

      case 24:
      case 32:
            if (isPReP) {
                  var->red.offset = 8;
                  var->green.offset = 16;
                  var->blue.offset = 24;
            } else {
                  var->red.offset = 16;
                  var->green.offset = 8;
                  var->blue.offset = 0;
            }
            var->red.length = 8;
            var->green.length = 8;
            var->blue.length = 8;
            break;

      default:
            DPRINTK("Unsupported bpp size: %d\n", var->bits_per_pixel);
            assert(false);
            /* should never occur */
            break;
      }

      var->red.msb_right =
          var->green.msb_right =
          var->blue.msb_right =
          var->transp.offset =
          var->transp.length =
          var->transp.msb_right = 0;

      yres = var->yres;
      if (var->vmode & FB_VMODE_DOUBLE)
            yres *= 2;
      else if (var->vmode & FB_VMODE_INTERLACED)
            yres = (yres + 1) / 2;

      if (yres >= 1280) {
            printk(KERN_ERR "cirrusfb: ERROR: VerticalTotal >= 1280; "
                  "special treatment required! (TODO)\n");
            DPRINTK("EXIT - EINVAL error\n");
            return -EINVAL;
      }

      return 0;
}

static int cirrusfb_decode_var(const struct fb_var_screeninfo *var,
                        struct cirrusfb_regs *regs,
                        struct fb_info *info)
{
      long freq;
      long maxclock;
      int maxclockidx = var->bits_per_pixel >> 3;
      struct cirrusfb_info *cinfo = info->par;
      int xres, hfront, hsync, hback;
      int yres, vfront, vsync, vback;

      switch (var->bits_per_pixel) {
      case 1:
            info->fix.line_length = var->xres_virtual / 8;
            info->fix.visual = FB_VISUAL_MONO10;
            break;

      case 8:
            info->fix.line_length = var->xres_virtual;
            info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
            break;

      case 16:
      case 24:
      case 32:
            info->fix.line_length = var->xres_virtual * maxclockidx;
            info->fix.visual = FB_VISUAL_DIRECTCOLOR;
            break;

      default:
            DPRINTK("Unsupported bpp size: %d\n", var->bits_per_pixel);
            assert(false);
            /* should never occur */
            break;
      }

      info->fix.type = FB_TYPE_PACKED_PIXELS;

      /* convert from ps to kHz */
      freq = PICOS2KHZ(var->pixclock);

      DPRINTK("desired pixclock: %ld kHz\n", freq);

      maxclock = cirrusfb_board_info[cinfo->btype].maxclock[maxclockidx];
      regs->multiplexing = 0;

      /* If the frequency is greater than we can support, we might be able
       * to use multiplexing for the video mode */
      if (freq > maxclock) {
            switch (cinfo->btype) {
            case BT_ALPINE:
            case BT_GD5480:
                  regs->multiplexing = 1;
                  break;

            default:
                  printk(KERN_ERR "cirrusfb: Frequency greater "
                        "than maxclock (%ld kHz)\n", maxclock);
                  DPRINTK("EXIT - return -EINVAL\n");
                  return -EINVAL;
            }
      }
#if 0
      /* TODO: If we have a 1MB 5434, we need to put ourselves in a mode where
       * the VCLK is double the pixel clock. */
      switch (var->bits_per_pixel) {
      case 16:
      case 32:
            if (regs->HorizRes <= 800)
                  /* Xbh has this type of clock for 32-bit */
                  freq /= 2;
            break;
      }
#endif

      bestclock(freq, &regs->freq, &regs->nom, &regs->den, &regs->div,
              maxclock);
      regs->mclk = cirrusfb_get_mclk(freq, var->bits_per_pixel,
                              &regs->divMCLK);

      xres = var->xres;
      hfront = var->right_margin;
      hsync = var->hsync_len;
      hback = var->left_margin;

      yres = var->yres;
      vfront = var->lower_margin;
      vsync = var->vsync_len;
      vback = var->upper_margin;

      if (var->vmode & FB_VMODE_DOUBLE) {
            yres *= 2;
            vfront *= 2;
            vsync *= 2;
            vback *= 2;
      } else if (var->vmode & FB_VMODE_INTERLACED) {
            yres = (yres + 1) / 2;
            vfront = (vfront + 1) / 2;
            vsync = (vsync + 1) / 2;
            vback = (vback + 1) / 2;
      }
      regs->HorizRes = xres;
      regs->HorizTotal = (xres + hfront + hsync + hback) / 8 - 5;
      regs->HorizDispEnd = xres / 8 - 1;
      regs->HorizBlankStart = xres / 8;
      /* does not count with "-5" */
      regs->HorizBlankEnd = regs->HorizTotal + 5;
      regs->HorizSyncStart = (xres + hfront) / 8 + 1;
      regs->HorizSyncEnd = (xres + hfront + hsync) / 8 + 1;

      regs->VertRes = yres;
      regs->VertTotal = yres + vfront + vsync + vback - 2;
      regs->VertDispEnd = yres - 1;
      regs->VertBlankStart = yres;
      regs->VertBlankEnd = regs->VertTotal;
      regs->VertSyncStart = yres + vfront - 1;
      regs->VertSyncEnd = yres + vfront + vsync - 1;

      if (regs->VertRes >= 1024) {
            regs->VertTotal /= 2;
            regs->VertSyncStart /= 2;
            regs->VertSyncEnd /= 2;
            regs->VertDispEnd /= 2;
      }
      if (regs->multiplexing) {
            regs->HorizTotal /= 2;
            regs->HorizSyncStart /= 2;
            regs->HorizSyncEnd /= 2;
            regs->HorizDispEnd /= 2;
      }

      return 0;
}

static void cirrusfb_set_mclk(const struct cirrusfb_info *cinfo, int val,
                        int div)
{
      assert(cinfo != NULL);

      if (div == 2) {
            /* VCLK = MCLK/2 */
            unsigned char old = vga_rseq(cinfo->regbase, CL_SEQR1E);
            vga_wseq(cinfo->regbase, CL_SEQR1E, old | 0x1);
            vga_wseq(cinfo->regbase, CL_SEQR1F, 0x40 | (val & 0x3f));
      } else if (div == 1) {
            /* VCLK = MCLK */
            unsigned char old = vga_rseq(cinfo->regbase, CL_SEQR1E);
            vga_wseq(cinfo->regbase, CL_SEQR1E, old & ~0x1);
            vga_wseq(cinfo->regbase, CL_SEQR1F, 0x40 | (val & 0x3f));
      } else {
            vga_wseq(cinfo->regbase, CL_SEQR1F, val & 0x3f);
      }
}

/*************************************************************************
      cirrusfb_set_par_foo()

      actually writes the values for a new video mode into the hardware,
**************************************************************************/
static int cirrusfb_set_par_foo(struct fb_info *info)
{
      struct cirrusfb_info *cinfo = info->par;
      struct fb_var_screeninfo *var = &info->var;
      struct cirrusfb_regs regs;
      u8 __iomem *regbase = cinfo->regbase;
      unsigned char tmp;
      int offset = 0, err;
      const struct cirrusfb_board_info_rec *bi;

      DPRINTK("ENTER\n");
      DPRINTK("Requested mode: %dx%dx%d\n",
             var->xres, var->yres, var->bits_per_pixel);
      DPRINTK("pixclock: %d\n", var->pixclock);

      init_vgachip(info);

      err = cirrusfb_decode_var(var, &regs, info);
      if (err) {
            /* should never happen */
            DPRINTK("mode change aborted.  invalid var.\n");
            return -EINVAL;
      }

      bi = &cirrusfb_board_info[cinfo->btype];

      /* unlock register VGA_CRTC_H_TOTAL..CRT7 */
      vga_wcrt(regbase, VGA_CRTC_V_SYNC_END, 0x20);   /* previously: 0x00) */

      /* if debugging is enabled, all parameters get output before writing */
      DPRINTK("CRT0: %ld\n", regs.HorizTotal);
      vga_wcrt(regbase, VGA_CRTC_H_TOTAL, regs.HorizTotal);

      DPRINTK("CRT1: %ld\n", regs.HorizDispEnd);
      vga_wcrt(regbase, VGA_CRTC_H_DISP, regs.HorizDispEnd);

      DPRINTK("CRT2: %ld\n", regs.HorizBlankStart);
      vga_wcrt(regbase, VGA_CRTC_H_BLANK_START, regs.HorizBlankStart);

      /*  + 128: Compatible read */
      DPRINTK("CRT3: 128+%ld\n", regs.HorizBlankEnd % 32);
      vga_wcrt(regbase, VGA_CRTC_H_BLANK_END,
             128 + (regs.HorizBlankEnd % 32));

      DPRINTK("CRT4: %ld\n", regs.HorizSyncStart);
      vga_wcrt(regbase, VGA_CRTC_H_SYNC_START, regs.HorizSyncStart);

      tmp = regs.HorizSyncEnd % 32;
      if (regs.HorizBlankEnd & 32)
            tmp += 128;
      DPRINTK("CRT5: %d\n", tmp);
      vga_wcrt(regbase, VGA_CRTC_H_SYNC_END, tmp);

      DPRINTK("CRT6: %ld\n", regs.VertTotal & 0xff);
      vga_wcrt(regbase, VGA_CRTC_V_TOTAL, (regs.VertTotal & 0xff));

      tmp = 16;         /* LineCompare bit #9 */
      if (regs.VertTotal & 256)
            tmp |= 1;
      if (regs.VertDispEnd & 256)
            tmp |= 2;
      if (regs.VertSyncStart & 256)
            tmp |= 4;
      if (regs.VertBlankStart & 256)
            tmp |= 8;
      if (regs.VertTotal & 512)
            tmp |= 32;
      if (regs.VertDispEnd & 512)
            tmp |= 64;
      if (regs.VertSyncStart & 512)
            tmp |= 128;
      DPRINTK("CRT7: %d\n", tmp);
      vga_wcrt(regbase, VGA_CRTC_OVERFLOW, tmp);

      tmp = 0x40;       /* LineCompare bit #8 */
      if (regs.VertBlankStart & 512)
            tmp |= 0x20;
      if (var->vmode & FB_VMODE_DOUBLE)
            tmp |= 0x80;
      DPRINTK("CRT9: %d\n", tmp);
      vga_wcrt(regbase, VGA_CRTC_MAX_SCAN, tmp);

      DPRINTK("CRT10: %ld\n", regs.VertSyncStart & 0xff);
      vga_wcrt(regbase, VGA_CRTC_V_SYNC_START, regs.VertSyncStart & 0xff);

      DPRINTK("CRT11: 64+32+%ld\n", regs.VertSyncEnd % 16);
      vga_wcrt(regbase, VGA_CRTC_V_SYNC_END, regs.VertSyncEnd % 16 + 64 + 32);

      DPRINTK("CRT12: %ld\n", regs.VertDispEnd & 0xff);
      vga_wcrt(regbase, VGA_CRTC_V_DISP_END, regs.VertDispEnd & 0xff);

      DPRINTK("CRT15: %ld\n", regs.VertBlankStart & 0xff);
      vga_wcrt(regbase, VGA_CRTC_V_BLANK_START, regs.VertBlankStart & 0xff);

      DPRINTK("CRT16: %ld\n", regs.VertBlankEnd & 0xff);
      vga_wcrt(regbase, VGA_CRTC_V_BLANK_END, regs.VertBlankEnd & 0xff);

      DPRINTK("CRT18: 0xff\n");
      vga_wcrt(regbase, VGA_CRTC_LINE_COMPARE, 0xff);

      tmp = 0;
      if (var->vmode & FB_VMODE_INTERLACED)
            tmp |= 1;
      if (regs.HorizBlankEnd & 64)
            tmp |= 16;
      if (regs.HorizBlankEnd & 128)
            tmp |= 32;
      if (regs.VertBlankEnd & 256)
            tmp |= 64;
      if (regs.VertBlankEnd & 512)
            tmp |= 128;

      DPRINTK("CRT1a: %d\n", tmp);
      vga_wcrt(regbase, CL_CRT1A, tmp);

      /* set VCLK0 */
      /* hardware RefClock: 14.31818 MHz */
      /* formula: VClk = (OSC * N) / (D * (1+P)) */
      /* Example: VClk = (14.31818 * 91) / (23 * (1+1)) = 28.325 MHz */

      vga_wseq(regbase, CL_SEQRB, regs.nom);
      tmp = regs.den << 1;
      if (regs.div != 0)
            tmp |= 1;

      /* 6 bit denom; ONLY 5434!!! (bugged me 10 days) */
      if ((cinfo->btype == BT_SD64) ||
          (cinfo->btype == BT_ALPINE) ||
          (cinfo->btype == BT_GD5480))
            tmp |= 0x80;

      DPRINTK("CL_SEQR1B: %ld\n", (long) tmp);
      vga_wseq(regbase, CL_SEQR1B, tmp);

      if (regs.VertRes >= 1024)
            /* 1280x1024 */
            vga_wcrt(regbase, VGA_CRTC_MODE, 0xc7);
      else
            /* mode control: VGA_CRTC_START_HI enable, ROTATE(?), 16bit
             * address wrap, no compat. */
            vga_wcrt(regbase, VGA_CRTC_MODE, 0xc3);

/* HAEH?    vga_wcrt(regbase, VGA_CRTC_V_SYNC_END, 0x20);
 * previously: 0x00  unlock VGA_CRTC_H_TOTAL..CRT7 */

      /* don't know if it would hurt to also program this if no interlaced */
      /* mode is used, but I feel better this way.. :-) */
      if (var->vmode & FB_VMODE_INTERLACED)
            vga_wcrt(regbase, VGA_CRTC_REGS, regs.HorizTotal / 2);
      else
            vga_wcrt(regbase, VGA_CRTC_REGS, 0x00);   /* interlace control */

      vga_wseq(regbase, VGA_SEQ_CHARACTER_MAP, 0);

      /* adjust horizontal/vertical sync type (low/high) */
      /* enable display memory & CRTC I/O address for color mode */
      tmp = 0x03;
      if (var->sync & FB_SYNC_HOR_HIGH_ACT)
            tmp |= 0x40;
      if (var->sync & FB_SYNC_VERT_HIGH_ACT)
            tmp |= 0x80;
      WGen(cinfo, VGA_MIS_W, tmp);

      /* Screen A Preset Row-Scan register */
      vga_wcrt(regbase, VGA_CRTC_PRESET_ROW, 0);
      /* text cursor on and start line */
      vga_wcrt(regbase, VGA_CRTC_CURSOR_START, 0);
      /* text cursor end line */
      vga_wcrt(regbase, VGA_CRTC_CURSOR_END, 31);

      /******************************************************
       *
       * 1 bpp
       *
       */

      /* programming for different color depths */
      if (var->bits_per_pixel == 1) {
            DPRINTK("cirrusfb: preparing for 1 bit deep display\n");
            vga_wgfx(regbase, VGA_GFX_MODE, 0); /* mode register */

            /* SR07 */
            switch (cinfo->btype) {
            case BT_SD64:
            case BT_PICCOLO:
            case BT_PICASSO:
            case BT_SPECTRUM:
            case BT_PICASSO4:
            case BT_ALPINE:
            case BT_GD5480:
                  DPRINTK(" (for GD54xx)\n");
                  vga_wseq(regbase, CL_SEQR7,
                          regs.multiplexing ?
                              bi->sr07_1bpp_mux : bi->sr07_1bpp);
                  break;

            case BT_LAGUNA:
                  DPRINTK(" (for GD546x)\n");
                  vga_wseq(regbase, CL_SEQR7,
                        vga_rseq(regbase, CL_SEQR7) & ~0x01);
                  break;

            default:
                  printk(KERN_WARNING "cirrusfb: unknown Board\n");
                  break;
            }

            /* Extended Sequencer Mode */
            switch (cinfo->btype) {
            case BT_SD64:
                  /* setting the SEQRF on SD64 is not necessary
                   * (only during init)
                   */
                  DPRINTK("(for SD64)\n");
                  /*  MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x1a);
                  break;

            case BT_PICCOLO:
            case BT_SPECTRUM:
                  DPRINTK("(for Piccolo/Spectrum)\n");
                  /* ### ueberall 0x22? */
                  /* ##vorher 1c MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x22);
                  /* evtl d0 bei 1 bit? avoid FIFO underruns..? */
                  vga_wseq(regbase, CL_SEQRF, 0xb0);
                  break;

            case BT_PICASSO:
                  DPRINTK("(for Picasso)\n");
                  /* ##vorher 22 MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x22);
                  /* ## vorher d0 avoid FIFO underruns..? */
                  vga_wseq(regbase, CL_SEQRF, 0xd0);
                  break;

            case BT_PICASSO4:
            case BT_ALPINE:
            case BT_GD5480:
            case BT_LAGUNA:
                  DPRINTK(" (for GD54xx)\n");
                  /* do nothing */
                  break;

            default:
                  printk(KERN_WARNING "cirrusfb: unknown Board\n");
                  break;
            }

            /* pixel mask: pass-through for first plane */
            WGen(cinfo, VGA_PEL_MSK, 0x01);
            if (regs.multiplexing)
                  /* hidden dac reg: 1280x1024 */
                  WHDR(cinfo, 0x4a);
            else
                  /* hidden dac: nothing */
                  WHDR(cinfo, 0);
            /* memory mode: odd/even, ext. memory */
            vga_wseq(regbase, VGA_SEQ_MEMORY_MODE, 0x06);
            /* plane mask: only write to first plane */
            vga_wseq(regbase, VGA_SEQ_PLANE_WRITE, 0x01);
            offset = var->xres_virtual / 16;
      }

      /******************************************************
       *
       * 8 bpp
       *
       */

      else if (var->bits_per_pixel == 8) {
            DPRINTK("cirrusfb: preparing for 8 bit deep display\n");
            switch (cinfo->btype) {
            case BT_SD64:
            case BT_PICCOLO:
            case BT_PICASSO:
            case BT_SPECTRUM:
            case BT_PICASSO4:
            case BT_ALPINE:
            case BT_GD5480:
                  DPRINTK(" (for GD54xx)\n");
                  vga_wseq(regbase, CL_SEQR7,
                          regs.multiplexing ?
                              bi->sr07_8bpp_mux : bi->sr07_8bpp);
                  break;

            case BT_LAGUNA:
                  DPRINTK(" (for GD546x)\n");
                  vga_wseq(regbase, CL_SEQR7,
                        vga_rseq(regbase, CL_SEQR7) | 0x01);
                  break;

            default:
                  printk(KERN_WARNING "cirrusfb: unknown Board\n");
                  break;
            }

            switch (cinfo->btype) {
            case BT_SD64:
                  /* MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x1d);
                  break;

            case BT_PICCOLO:
            case BT_PICASSO:
            case BT_SPECTRUM:
                  /* ### vorher 1c MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x22);
                  /* Fast Page-Mode writes */
                  vga_wseq(regbase, CL_SEQRF, 0xb0);
                  break;

            case BT_PICASSO4:
#ifdef CONFIG_ZORRO
                  /* ### INCOMPLETE!! */
                  vga_wseq(regbase, CL_SEQRF, 0xb8);
#endif
/*                vga_wseq(regbase, CL_SEQR1F, 0x1c); */
                  break;

            case BT_ALPINE:
                  DPRINTK(" (for GD543x)\n");
                  cirrusfb_set_mclk(cinfo, regs.mclk, regs.divMCLK);
                  /* We already set SRF and SR1F */
                  break;

            case BT_GD5480:
            case BT_LAGUNA:
                  DPRINTK(" (for GD54xx)\n");
                  /* do nothing */
                  break;

            default:
                  printk(KERN_WARNING "cirrusfb: unknown Board\n");
                  break;
            }

            /* mode register: 256 color mode */
            vga_wgfx(regbase, VGA_GFX_MODE, 64);
            /* pixel mask: pass-through all planes */
            WGen(cinfo, VGA_PEL_MSK, 0xff);
            if (regs.multiplexing)
                  /* hidden dac reg: 1280x1024 */
                  WHDR(cinfo, 0x4a);
            else
                  /* hidden dac: nothing */
                  WHDR(cinfo, 0);
            /* memory mode: chain4, ext. memory */
            vga_wseq(regbase, VGA_SEQ_MEMORY_MODE, 0x0a);
            /* plane mask: enable writing to all 4 planes */
            vga_wseq(regbase, VGA_SEQ_PLANE_WRITE, 0xff);
            offset = var->xres_virtual / 8;
      }

      /******************************************************
       *
       * 16 bpp
       *
       */

      else if (var->bits_per_pixel == 16) {
            DPRINTK("cirrusfb: preparing for 16 bit deep display\n");
            switch (cinfo->btype) {
            case BT_SD64:
                  /* Extended Sequencer Mode: 256c col. mode */
                  vga_wseq(regbase, CL_SEQR7, 0xf7);
                  /* MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x1e);
                  break;

            case BT_PICCOLO:
            case BT_SPECTRUM:
                  vga_wseq(regbase, CL_SEQR7, 0x87);
                  /* Fast Page-Mode writes */
                  vga_wseq(regbase, CL_SEQRF, 0xb0);
                  /* MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x22);
                  break;

            case BT_PICASSO:
                  vga_wseq(regbase, CL_SEQR7, 0x27);
                  /* Fast Page-Mode writes */
                  vga_wseq(regbase, CL_SEQRF, 0xb0);
                  /* MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x22);
                  break;

            case BT_PICASSO4:
                  vga_wseq(regbase, CL_SEQR7, 0x27);
/*                vga_wseq(regbase, CL_SEQR1F, 0x1c);  */
                  break;

            case BT_ALPINE:
                  DPRINTK(" (for GD543x)\n");
                  if (regs.HorizRes >= 1024)
                        vga_wseq(regbase, CL_SEQR7, 0xa7);
                  else
                        vga_wseq(regbase, CL_SEQR7, 0xa3);
                  cirrusfb_set_mclk(cinfo, regs.mclk, regs.divMCLK);
                  break;

            case BT_GD5480:
                  DPRINTK(" (for GD5480)\n");
                  vga_wseq(regbase, CL_SEQR7, 0x17);
                  /* We already set SRF and SR1F */
                  break;

            case BT_LAGUNA:
                  DPRINTK(" (for GD546x)\n");
                  vga_wseq(regbase, CL_SEQR7,
                        vga_rseq(regbase, CL_SEQR7) & ~0x01);
                  break;

            default:
                  printk(KERN_WARNING "CIRRUSFB: unknown Board\n");
                  break;
            }

            /* mode register: 256 color mode */
            vga_wgfx(regbase, VGA_GFX_MODE, 64);
            /* pixel mask: pass-through all planes */
            WGen(cinfo, VGA_PEL_MSK, 0xff);
#ifdef CONFIG_PCI
            WHDR(cinfo, 0xc0);      /* Copy Xbh */
#elif defined(CONFIG_ZORRO)
            /* FIXME: CONFIG_PCI and CONFIG_ZORRO may be defined both */
            WHDR(cinfo, 0xa0);      /* hidden dac reg: nothing special */
#endif
            /* memory mode: chain4, ext. memory */
            vga_wseq(regbase, VGA_SEQ_MEMORY_MODE, 0x0a);
            /* plane mask: enable writing to all 4 planes */
            vga_wseq(regbase, VGA_SEQ_PLANE_WRITE, 0xff);
            offset = var->xres_virtual / 4;
      }

      /******************************************************
       *
       * 32 bpp
       *
       */

      else if (var->bits_per_pixel == 32) {
            DPRINTK("cirrusfb: preparing for 24/32 bit deep display\n");
            switch (cinfo->btype) {
            case BT_SD64:
                  /* Extended Sequencer Mode: 256c col. mode */
                  vga_wseq(regbase, CL_SEQR7, 0xf9);
                  /* MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x1e);
                  break;

            case BT_PICCOLO:
            case BT_SPECTRUM:
                  vga_wseq(regbase, CL_SEQR7, 0x85);
                  /* Fast Page-Mode writes */
                  vga_wseq(regbase, CL_SEQRF, 0xb0);
                  /* MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x22);
                  break;

            case BT_PICASSO:
                  vga_wseq(regbase, CL_SEQR7, 0x25);
                  /* Fast Page-Mode writes */
                  vga_wseq(regbase, CL_SEQRF, 0xb0);
                  /* MCLK select */
                  vga_wseq(regbase, CL_SEQR1F, 0x22);
                  break;

            case BT_PICASSO4:
                  vga_wseq(regbase, CL_SEQR7, 0x25);
/*                vga_wseq(regbase, CL_SEQR1F, 0x1c);  */
                  break;

            case BT_ALPINE:
                  DPRINTK(" (for GD543x)\n");
                  vga_wseq(regbase, CL_SEQR7, 0xa9);
                  cirrusfb_set_mclk(cinfo, regs.mclk, regs.divMCLK);
                  break;

            case BT_GD5480:
                  DPRINTK(" (for GD5480)\n");
                  vga_wseq(regbase, CL_SEQR7, 0x19);
                  /* We already set SRF and SR1F */
                  break;

            case BT_LAGUNA:
                  DPRINTK(" (for GD546x)\n");
                  vga_wseq(regbase, CL_SEQR7,
                        vga_rseq(regbase, CL_SEQR7) & ~0x01);
                  break;

            default:
                  printk(KERN_WARNING "cirrusfb: unknown Board\n");
                  break;
            }

            /* mode register: 256 color mode */
            vga_wgfx(regbase, VGA_GFX_MODE, 64);
            /* pixel mask: pass-through all planes */
            WGen(cinfo, VGA_PEL_MSK, 0xff);
            /* hidden dac reg: 8-8-8 mode (24 or 32) */
            WHDR(cinfo, 0xc5);
            /* memory mode: chain4, ext. memory */
            vga_wseq(regbase, VGA_SEQ_MEMORY_MODE, 0x0a);
            /* plane mask: enable writing to all 4 planes */
            vga_wseq(regbase, VGA_SEQ_PLANE_WRITE, 0xff);
            offset = var->xres_virtual / 4;
      }

      /******************************************************
       *
       * unknown/unsupported bpp
       *
       */

      else
            printk(KERN_ERR "cirrusfb: What's this?? "
                  " requested color depth == %d.\n",
                  var->bits_per_pixel);

      vga_wcrt(regbase, VGA_CRTC_OFFSET, offset & 0xff);
      tmp = 0x22;
      if (offset & 0x100)
            tmp |= 0x10;      /* offset overflow bit */

      /* screen start addr #16-18, fastpagemode cycles */
      vga_wcrt(regbase, CL_CRT1B, tmp);

      if (cinfo->btype == BT_SD64 ||
          cinfo->btype == BT_PICASSO4 ||
          cinfo->btype == BT_ALPINE ||
          cinfo->btype == BT_GD5480)
            /* screen start address bit 19 */
            vga_wcrt(regbase, CL_CRT1D, 0x00);

      /* text cursor location high */
      vga_wcrt(regbase, VGA_CRTC_CURSOR_HI, 0);
      /* text cursor location low */
      vga_wcrt(regbase, VGA_CRTC_CURSOR_LO, 0);
      /* underline row scanline = at very bottom */
      vga_wcrt(regbase, VGA_CRTC_UNDERLINE, 0);

      /* controller mode */
      vga_wattr(regbase, VGA_ATC_MODE, 1);
      /* overscan (border) color */
      vga_wattr(regbase, VGA_ATC_OVERSCAN, 0);
      /* color plane enable */
      vga_wattr(regbase, VGA_ATC_PLANE_ENABLE, 15);
      /* pixel panning */
      vga_wattr(regbase, CL_AR33, 0);
      /* color select */
      vga_wattr(regbase, VGA_ATC_COLOR_PAGE, 0);

      /* [ EGS: SetOffset(); ] */
      /* From SetOffset(): Turn on VideoEnable bit in Attribute controller */
      AttrOn(cinfo);

      /* set/reset register */
      vga_wgfx(regbase, VGA_GFX_SR_VALUE, 0);
      /* set/reset enable */
      vga_wgfx(regbase, VGA_GFX_SR_ENABLE, 0);
      /* color compare */
      vga_wgfx(regbase, VGA_GFX_COMPARE_VALUE, 0);
      /* data rotate */
      vga_wgfx(regbase, VGA_GFX_DATA_ROTATE, 0);
      /* read map select */
      vga_wgfx(regbase, VGA_GFX_PLANE_READ, 0);
      /* miscellaneous register */
      vga_wgfx(regbase, VGA_GFX_MISC, 1);
      /* color don't care */
      vga_wgfx(regbase, VGA_GFX_COMPARE_MASK, 15);
      /* bit mask */
      vga_wgfx(regbase, VGA_GFX_BIT_MASK, 255);

      /* graphics cursor attributes: nothing special */
      vga_wseq(regbase, CL_SEQR12, 0x0);

      /* finally, turn on everything - turn off "FullBandwidth" bit */
      /* also, set "DotClock%2" bit where requested */
      tmp = 0x01;

/*** FB_VMODE_CLOCK_HALVE in linux/fb.h not defined anymore ?
    if (var->vmode & FB_VMODE_CLOCK_HALVE)
      tmp |= 0x08;
*/

      vga_wseq(regbase, VGA_SEQ_CLOCK_MODE, tmp);
      DPRINTK("CL_SEQR1: %d\n", tmp);

      cinfo->currentmode = regs;

      /* pan to requested offset */
      cirrusfb_pan_display(var, info);

#ifdef CIRRUSFB_DEBUG
      cirrusfb_dump();
#endif

      DPRINTK("EXIT\n");
      return 0;
}

/* for some reason incomprehensible to me, cirrusfb requires that you write
 * the registers twice for the settings to take..grr. -dte */
static int cirrusfb_set_par(struct fb_info *info)
{
      cirrusfb_set_par_foo(info);
      return cirrusfb_set_par_foo(info);
}

static int cirrusfb_setcolreg(unsigned regno, unsigned red, unsigned green,
                        unsigned blue, unsigned transp,
                        struct fb_info *info)
{
      struct cirrusfb_info *cinfo = info->par;

      if (regno > 255)
            return -EINVAL;

      if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
            u32 v;
            red >>= (16 - info->var.red.length);
            green >>= (16 - info->var.green.length);
            blue >>= (16 - info->var.blue.length);

            if (regno >= 16)
                  return 1;
            v = (red << info->var.red.offset) |
                (green << info->var.green.offset) |
                (blue << info->var.blue.offset);

            cinfo->pseudo_palette[regno] = v;
            return 0;
      }

      if (info->var.bits_per_pixel == 8)
            WClut(cinfo, regno, red >> 10, green >> 10, blue >> 10);

      return 0;

}

/*************************************************************************
      cirrusfb_pan_display()

      performs display panning - provided hardware permits this
**************************************************************************/
static int cirrusfb_pan_display(struct fb_var_screeninfo *var,
                        struct fb_info *info)
{
      int xoffset = 0;
      int yoffset = 0;
      unsigned long base;
      unsigned char tmp = 0, tmp2 = 0, xpix;
      struct cirrusfb_info *cinfo = info->par;

      DPRINTK("ENTER\n");
      DPRINTK("virtual offset: (%d,%d)\n", var->xoffset, var->yoffset);

      /* no range checks for xoffset and yoffset,   */
      /* as fb_pan_display has already done this */
      if (var->vmode & FB_VMODE_YWRAP)
            return -EINVAL;

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

      xoffset = var->xoffset * info->var.bits_per_pixel / 8;
      yoffset = var->yoffset;

      base = yoffset * info->fix.line_length + xoffset;

      if (info->var.bits_per_pixel == 1) {
            /* base is already correct */
            xpix = (unsigned char) (var->xoffset % 8);
      } else {
            base /= 4;
            xpix = (unsigned char) ((xoffset % 4) * 2);
      }

      cirrusfb_WaitBLT(cinfo->regbase); /* make sure all the BLT's are done */

      /* lower 8 + 8 bits of screen start address */
      vga_wcrt(cinfo->regbase, VGA_CRTC_START_LO,
             (unsigned char) (base & 0xff));
      vga_wcrt(cinfo->regbase, VGA_CRTC_START_HI,
             (unsigned char) (base >> 8));

      /* construct bits 16, 17 and 18 of screen start address */
      if (base & 0x10000)
            tmp |= 0x01;
      if (base & 0x20000)
            tmp |= 0x04;
      if (base & 0x40000)
            tmp |= 0x08;

      /* 0xf2 is %11110010, exclude tmp bits */
      tmp2 = (vga_rcrt(cinfo->regbase, CL_CRT1B) & 0xf2) | tmp;
      vga_wcrt(cinfo->regbase, CL_CRT1B, tmp2);

      /* construct bit 19 of screen start address */
      if (cirrusfb_board_info[cinfo->btype].scrn_start_bit19)
            vga_wcrt(cinfo->regbase, CL_CRT1D, (base >> 12) & 0x80);

      /* write pixel panning value to AR33; this does not quite work in 8bpp
       *
       * ### Piccolo..? Will this work?
       */
      if (info->var.bits_per_pixel == 1)
            vga_wattr(cinfo->regbase, CL_AR33, xpix);

      cirrusfb_WaitBLT(cinfo->regbase);

      DPRINTK("EXIT\n");
      return 0;
}

static int cirrusfb_blank(int blank_mode, struct fb_info *info)
{
      /*
       * Blank the screen if blank_mode != 0, else unblank. If blank == NULL
       * then the caller blanks by setting the CLUT (Color Look Up Table)
       * 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
       *   blank_mode == 3: suspend hsync
       *   blank_mode == 4: powerdown
       */
      unsigned char val;
      struct cirrusfb_info *cinfo = info->par;
      int current_mode = cinfo->blank_mode;

      DPRINTK("ENTER, blank mode = %d\n", blank_mode);

      if (info->state != FBINFO_STATE_RUNNING ||
          current_mode == blank_mode) {
            DPRINTK("EXIT, returning 0\n");
            return 0;
      }

      /* Undo current */
      if (current_mode == FB_BLANK_NORMAL ||
          current_mode == FB_BLANK_UNBLANK) {
            /* unblank the screen */
            val = vga_rseq(cinfo->regbase, VGA_SEQ_CLOCK_MODE);
            /* clear "FullBandwidth" bit */
            vga_wseq(cinfo->regbase, VGA_SEQ_CLOCK_MODE, val & 0xdf);
            /* and undo VESA suspend trickery */
            vga_wgfx(cinfo->regbase, CL_GRE, 0x00);
      }

      /* set new */
      if (blank_mode > FB_BLANK_NORMAL) {
            /* blank the screen */
            val = vga_rseq(cinfo->regbase, VGA_SEQ_CLOCK_MODE);
            /* set "FullBandwidth" bit */
            vga_wseq(cinfo->regbase, VGA_SEQ_CLOCK_MODE, val | 0x20);
      }

      switch (blank_mode) {
      case FB_BLANK_UNBLANK:
      case FB_BLANK_NORMAL:
            break;
      case FB_BLANK_VSYNC_SUSPEND:
            vga_wgfx(cinfo->regbase, CL_GRE, 0x04);
            break;
      case FB_BLANK_HSYNC_SUSPEND:
            vga_wgfx(cinfo->regbase, CL_GRE, 0x02);
            break;
      case FB_BLANK_POWERDOWN:
            vga_wgfx(cinfo->regbase, CL_GRE, 0x06);
            break;
      default:
            DPRINTK("EXIT, returning 1\n");
            return 1;
      }

      cinfo->blank_mode = blank_mode;
      DPRINTK("EXIT, returning 0\n");

      /* Let fbcon do a soft blank for us */
      return (blank_mode == FB_BLANK_NORMAL) ? 1 : 0;
}
/**** END   Hardware specific Routines **************************************/
/****************************************************************************/
/**** BEGIN Internal Routines ***********************************************/

static void init_vgachip(struct fb_info *info)
{
      struct cirrusfb_info *cinfo = info->par;
      const struct cirrusfb_board_info_rec *bi;

      DPRINTK("ENTER\n");

      assert(cinfo != NULL);

      bi = &cirrusfb_board_info[cinfo->btype];

      /* reset board globally */
      switch (cinfo->btype) {
      case BT_PICCOLO:
            WSFR(cinfo, 0x01);
            udelay(500);
            WSFR(cinfo, 0x51);
            udelay(500);
            break;
      case BT_PICASSO:
            WSFR2(cinfo, 0xff);
            udelay(500);
            break;
      case BT_SD64:
      case BT_SPECTRUM:
            WSFR(cinfo, 0x1f);
            udelay(500);
            WSFR(cinfo, 0x4f);
            udelay(500);
            break;
      case BT_PICASSO4:
            /* disable flickerfixer */
            vga_wcrt(cinfo->regbase, CL_CRT51, 0x00);
            mdelay(100);
            /* from Klaus' NetBSD driver: */
            vga_wgfx(cinfo->regbase, CL_GR2F, 0x00);
            /* put blitter into 542x compat */
            vga_wgfx(cinfo->regbase, CL_GR33, 0x00);
            /* mode */
            vga_wgfx(cinfo->regbase, CL_GR31, 0x00);
            break;

      case BT_GD5480:
            /* from Klaus' NetBSD driver: */
            vga_wgfx(cinfo->regbase, CL_GR2F, 0x00);
            break;

      case BT_ALPINE:
            /* Nothing to do to reset the board. */
            break;

      default:
            printk(KERN_ERR "cirrusfb: Warning: Unknown board type\n");
            break;
      }

      /* make sure RAM size set by this point */
      assert(info->screen_size > 0);

      /* the P4 is not fully initialized here; I rely on it having been */
      /* inited under AmigaOS already, which seems to work just fine    */
      /* (Klaus advised to do it this way)                        */

      if (cinfo->btype != BT_PICASSO4) {
            WGen(cinfo, CL_VSSM, 0x10);   /* EGS: 0x16 */
            WGen(cinfo, CL_POS102, 0x01);
            WGen(cinfo, CL_VSSM, 0x08);   /* EGS: 0x0e */

            if (cinfo->btype != BT_SD64)
                  WGen(cinfo, CL_VSSM2, 0x01);

            /* reset sequencer logic */
            vga_wseq(cinfo->regbase, CL_SEQR0, 0x03);

            /* FullBandwidth (video off) and 8/9 dot clock */
            vga_wseq(cinfo->regbase, VGA_SEQ_CLOCK_MODE, 0x21);
            /* polarity (-/-), disable access to display memory,
             * VGA_CRTC_START_HI base address: color
             */
            WGen(cinfo, VGA_MIS_W, 0xc1);

            /* "magic cookie" - doesn't make any sense to me.. */
/*      vga_wgfx(cinfo->regbase, CL_GRA, 0xce);   */
            /* unlock all extension registers */
            vga_wseq(cinfo->regbase, CL_SEQR6, 0x12);

            /* reset blitter */
            vga_wgfx(cinfo->regbase, CL_GR31, 0x04);

            switch (cinfo->btype) {
            case BT_GD5480:
                  vga_wseq(cinfo->regbase, CL_SEQRF, 0x98);
                  break;
            case BT_ALPINE:
                  break;
            case BT_SD64:
                  vga_wseq(cinfo->regbase, CL_SEQRF, 0xb8);
                  break;
            default:
                  vga_wseq(cinfo->regbase, CL_SEQR16, 0x0f);
                  vga_wseq(cinfo->regbase, CL_SEQRF, 0xb0);
                  break;
            }
      }
      /* plane mask: nothing */
      vga_wseq(cinfo->regbase, VGA_SEQ_PLANE_WRITE, 0xff);
      /* character map select: doesn't even matter in gx mode */
      vga_wseq(cinfo->regbase, VGA_SEQ_CHARACTER_MAP, 0x00);
      /* memory mode: chain-4, no odd/even, ext. memory */
      vga_wseq(cinfo->regbase, VGA_SEQ_MEMORY_MODE, 0x0e);

      /* controller-internal base address of video memory */
      if (bi->init_sr07)
            vga_wseq(cinfo->regbase, CL_SEQR7, bi->sr07);

      /*  vga_wseq(cinfo->regbase, CL_SEQR8, 0x00); */
      /* EEPROM control: shouldn't be necessary to write to this at all.. */

      /* graphics cursor X position (incomplete; position gives rem. 3 bits */
      vga_wseq(cinfo->regbase, CL_SEQR10, 0x00);
      /* graphics cursor Y position (..."... ) */
      vga_wseq(cinfo->regbase, CL_SEQR11, 0x00);
      /* graphics cursor attributes */
      vga_wseq(cinfo->regbase, CL_SEQR12, 0x00);
      /* graphics cursor pattern address */
      vga_wseq(cinfo->regbase, CL_SEQR13, 0x00);

      /* writing these on a P4 might give problems..  */
      if (cinfo->btype != BT_PICASSO4) {
            /* configuration readback and ext. color */
            vga_wseq(cinfo->regbase, CL_SEQR17, 0x00);
            /* signature generator */
            vga_wseq(cinfo->regbase, CL_SEQR18, 0x02);
      }

      /* MCLK select etc. */
      if (bi->init_sr1f)
            vga_wseq(cinfo->regbase, CL_SEQR1F, bi->sr1f);

      /* Screen A preset row scan: none */
      vga_wcrt(cinfo->regbase, VGA_CRTC_PRESET_ROW, 0x00);
      /* Text cursor start: disable text cursor */
      vga_wcrt(cinfo->regbase, VGA_CRTC_CURSOR_START, 0x20);
      /* Text cursor end: - */
      vga_wcrt(cinfo->regbase, VGA_CRTC_CURSOR_END, 0x00);
      /* Screen start address high: 0 */
      vga_wcrt(cinfo->regbase, VGA_CRTC_START_HI, 0x00);
      /* Screen start address low: 0 */
      vga_wcrt(cinfo->regbase, VGA_CRTC_START_LO, 0x00);
      /* text cursor location high: 0 */
      vga_wcrt(cinfo->regbase, VGA_CRTC_CURSOR_HI, 0x00);
      /* text cursor location low: 0 */
      vga_wcrt(cinfo->regbase, VGA_CRTC_CURSOR_LO, 0x00);

      /* Underline Row scanline: - */
      vga_wcrt(cinfo->regbase, VGA_CRTC_UNDERLINE, 0x00);
      /* mode control: timing enable, byte mode, no compat modes */
      vga_wcrt(cinfo->regbase, VGA_CRTC_MODE, 0xc3);
      /* Line Compare: not needed */
      vga_wcrt(cinfo->regbase, VGA_CRTC_LINE_COMPARE, 0x00);
      /* ### add 0x40 for text modes with > 30 MHz pixclock */
      /* ext. display controls: ext.adr. wrap */
      vga_wcrt(cinfo->regbase, CL_CRT1B, 0x02);

      /* Set/Reset registes: - */
      vga_wgfx(cinfo->regbase, VGA_GFX_SR_VALUE, 0x00);
      /* Set/Reset enable: - */
      vga_wgfx(cinfo->regbase, VGA_GFX_SR_ENABLE, 0x00);
      /* Color Compare: - */
      vga_wgfx(cinfo->regbase, VGA_GFX_COMPARE_VALUE, 0x00);
      /* Data Rotate: - */
      vga_wgfx(cinfo->regbase, VGA_GFX_DATA_ROTATE, 0x00);
      /* Read Map Select: - */
      vga_wgfx(cinfo->regbase, VGA_GFX_PLANE_READ, 0x00);
      /* Mode: conf. for 16/4/2 color mode, no odd/even, read/write mode 0 */
      vga_wgfx(cinfo->regbase, VGA_GFX_MODE, 0x00);
      /* Miscellaneous: memory map base address, graphics mode */
      vga_wgfx(cinfo->regbase, VGA_GFX_MISC, 0x01);
      /* Color Don't care: involve all planes */
      vga_wgfx(cinfo->regbase, VGA_GFX_COMPARE_MASK, 0x0f);
      /* Bit Mask: no mask at all */
      vga_wgfx(cinfo->regbase, VGA_GFX_BIT_MASK, 0xff);
      if (cinfo->btype == BT_ALPINE)
            /* (5434 can't have bit 3 set for bitblt) */
            vga_wgfx(cinfo->regbase, CL_GRB, 0x20);
      else
      /* Graphics controller mode extensions: finer granularity,
       * 8byte data latches
       */
            vga_wgfx(cinfo->regbase, CL_GRB, 0x28);

      vga_wgfx(cinfo->regbase, CL_GRC, 0xff);   /* Color Key compare: - */
      vga_wgfx(cinfo->regbase, CL_GRD, 0x00);   /* Color Key compare mask: - */
      vga_wgfx(cinfo->regbase, CL_GRE, 0x00);   /* Miscellaneous control: - */
      /* Background color byte 1: - */
      /*  vga_wgfx (cinfo->regbase, CL_GR10, 0x00); */
      /*  vga_wgfx (cinfo->regbase, CL_GR11, 0x00); */

      /* Attribute Controller palette registers: "identity mapping" */
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE0, 0x00);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE1, 0x01);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE2, 0x02);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE3, 0x03);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE4, 0x04);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE5, 0x05);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE6, 0x06);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE7, 0x07);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE8, 0x08);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTE9, 0x09);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTEA, 0x0a);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTEB, 0x0b);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTEC, 0x0c);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTED, 0x0d);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTEE, 0x0e);
      vga_wattr(cinfo->regbase, VGA_ATC_PALETTEF, 0x0f);

      /* Attribute Controller mode: graphics mode */
      vga_wattr(cinfo->regbase, VGA_ATC_MODE, 0x01);
      /* Overscan color reg.: reg. 0 */
      vga_wattr(cinfo->regbase, VGA_ATC_OVERSCAN, 0x00);
      /* Color Plane enable: Enable all 4 planes */
      vga_wattr(cinfo->regbase, VGA_ATC_PLANE_ENABLE, 0x0f);
/* ###  vga_wattr(cinfo->regbase, CL_AR33, 0x00); * Pixel Panning: - */
      /* Color Select: - */
      vga_wattr(cinfo->regbase, VGA_ATC_COLOR_PAGE, 0x00);

      WGen(cinfo, VGA_PEL_MSK, 0xff);     /* Pixel mask: no mask */

      if (cinfo->btype != BT_ALPINE && cinfo->btype != BT_GD5480)
      /* polarity (-/-), enable display mem,
       * VGA_CRTC_START_HI i/o base = color
       */
            WGen(cinfo, VGA_MIS_W, 0xc3);

      /* BLT Start/status: Blitter reset */
      vga_wgfx(cinfo->regbase, CL_GR31, 0x04);
      /* - " -       : "end-of-reset" */
      vga_wgfx(cinfo->regbase, CL_GR31, 0x00);

      /* misc... */
      WHDR(cinfo, 0);   /* Hidden DAC register: - */

      printk(KERN_DEBUG "cirrusfb: This board has %ld bytes of DRAM memory\n",
            info->screen_size);
      DPRINTK("EXIT\n");
      return;
}

static void switch_monitor(struct cirrusfb_info *cinfo, int on)
{
#ifdef CONFIG_ZORRO /* only works on Zorro boards */
      static int IsOn = 0;    /* XXX not ok for multiple boards */

      DPRINTK("ENTER\n");

      if (cinfo->btype == BT_PICASSO4)
            return;           /* nothing to switch */
      if (cinfo->btype == BT_ALPINE)
            return;           /* nothing to switch */
      if (cinfo->btype == BT_GD5480)
            return;           /* nothing to switch */
      if (cinfo->btype == BT_PICASSO) {
            if ((on && !IsOn) || (!on && IsOn))
                  WSFR(cinfo, 0xff);

            DPRINTK("EXIT\n");
            return;
      }
      if (on) {
            switch (cinfo->btype) {
            case BT_SD64:
                  WSFR(cinfo, cinfo->SFR | 0x21);
                  break;
            case BT_PICCOLO:
                  WSFR(cinfo, cinfo->SFR | 0x28);
                  break;
            case BT_SPECTRUM:
                  WSFR(cinfo, 0x6f);
                  break;
            default: /* do nothing */ break;
            }
      } else {
            switch (cinfo->btype) {
            case BT_SD64:
                  WSFR(cinfo, cinfo->SFR & 0xde);
                  break;
            case BT_PICCOLO:
                  WSFR(cinfo, cinfo->SFR & 0xd7);
                  break;
            case BT_SPECTRUM:
                  WSFR(cinfo, 0x4f);
                  break;
            default: /* do nothing */ break;
            }
      }

      DPRINTK("EXIT\n");
#endif /* CONFIG_ZORRO */
}

/******************************************/
/* Linux 2.6-style  accelerated functions */
/******************************************/

static void cirrusfb_fillrect(struct fb_info *info,
                        const struct fb_fillrect *region)
{
      struct fb_fillrect modded;
      int vxres, vyres;
      struct cirrusfb_info *cinfo = info->par;
      int m = info->var.bits_per_pixel;
      u32 color = (info->fix.visual == FB_VISUAL_TRUECOLOR) ?
            cinfo->pseudo_palette[region->color] : region->color;

      if (info->state != FBINFO_STATE_RUNNING)
            return;
      if (info->flags & FBINFO_HWACCEL_DISABLED) {
            cfb_fillrect(info, region);
            return;
      }

      vxres = info->var.xres_virtual;
      vyres = info->var.yres_virtual;

      memcpy(&modded, region, sizeof(struct fb_fillrect));

      if (!modded.width || !modded.height ||
         modded.dx >= vxres || modded.dy >= vyres)
            return;

      if (modded.dx + modded.width  > vxres)
            modded.width  = vxres - modded.dx;
      if (modded.dy + modded.height > vyres)
            modded.height = vyres - modded.dy;

      cirrusfb_RectFill(cinfo->regbase,
                    info->var.bits_per_pixel,
                    (region->dx * m) / 8, region->dy,
                    (region->width * m) / 8, region->height,
                    color,
                    info->fix.line_length);
}

static void cirrusfb_copyarea(struct fb_info *info,
                        const struct fb_copyarea *area)
{
      struct fb_copyarea modded;
      u32 vxres, vyres;
      struct cirrusfb_info *cinfo = info->par;
      int m = info->var.bits_per_pixel;

      if (info->state != FBINFO_STATE_RUNNING)
            return;
      if (info->flags & FBINFO_HWACCEL_DISABLED) {
            cfb_copyarea(info, area);
            return;
      }

      vxres = info->var.xres_virtual;
      vyres = info->var.yres_virtual;
      memcpy(&modded, area, sizeof(struct fb_copyarea));

      if (!modded.width || !modded.height ||
         modded.sx >= vxres || modded.sy >= vyres ||
         modded.dx >= vxres || modded.dy >= vyres)
            return;

      if (modded.sx + modded.width > vxres)
            modded.width = vxres - modded.sx;
      if (modded.dx + modded.width > vxres)
            modded.width = vxres - modded.dx;
      if (modded.sy + modded.height > vyres)
            modded.height = vyres - modded.sy;
      if (modded.dy + modded.height > vyres)
            modded.height = vyres - modded.dy;

      cirrusfb_BitBLT(cinfo->regbase, info->var.bits_per_pixel,
                  (area->sx * m) / 8, area->sy,
                  (area->dx * m) / 8, area->dy,
                  (area->width * m) / 8, area->height,
                  info->fix.line_length);

}

static void cirrusfb_imageblit(struct fb_info *info,
                         const struct fb_image *image)
{
      struct cirrusfb_info *cinfo = info->par;

      cirrusfb_WaitBLT(cinfo->regbase);
      cfb_imageblit(info, image);
}

#ifdef CONFIG_PPC_PREP
#define PREP_VIDEO_BASE ((volatile unsigned long) 0xC0000000)
#define PREP_IO_BASE    ((volatile unsigned char *) 0x80000000)
static void get_prep_addrs(unsigned long *display, unsigned long *registers)
{
      DPRINTK("ENTER\n");

      *display = PREP_VIDEO_BASE;
      *registers = (unsigned long) PREP_IO_BASE;

      DPRINTK("EXIT\n");
}

#endif                        /* CONFIG_PPC_PREP */

#ifdef CONFIG_PCI
static int release_io_ports;

/* Pulled the logic from XFree86 Cirrus driver to get the memory size,
 * based on the DRAM bandwidth bit and DRAM bank switching bit.  This
 * works with 1MB, 2MB and 4MB configurations (which the Motorola boards
 * seem to have. */
static unsigned int cirrusfb_get_memsize(u8 __iomem *regbase)
{
      unsigned long mem;
      unsigned char SRF;

      DPRINTK("ENTER\n");

      SRF = vga_rseq(regbase, CL_SEQRF);
      switch ((SRF & 0x18)) {
      case 0x08:
            mem = 512 * 1024;
            break;
      case 0x10:
            mem = 1024 * 1024;
            break;
      /* 64-bit DRAM data bus width; assume 2MB. Also indicates 2MB memory
       * on the 5430.
       */
      case 0x18:
            mem = 2048 * 1024;
            break;
      default:
            printk(KERN_WARNING "CLgenfb: Unknown memory size!\n");
            mem = 1024 * 1024;
      }
      if (SRF & 0x80)
      /* If DRAM bank switching is enabled, there must be twice as much
       * memory installed. (4MB on the 5434)
       */
            mem *= 2;

      /* TODO: Handling of GD5446/5480 (see XF86 sources ...) */

      DPRINTK("EXIT\n");
      return mem;
}

static void get_pci_addrs(const struct pci_dev *pdev,
                    unsigned long *display, unsigned long *registers)
{
      assert(pdev != NULL);
      assert(display != NULL);
      assert(registers != NULL);

      DPRINTK("ENTER\n");

      *display = 0;
      *registers = 0;

      /* This is a best-guess for now */

      if (pci_resource_flags(pdev, 0) & IORESOURCE_IO) {
            *display = pci_resource_start(pdev, 1);
            *registers = pci_resource_start(pdev, 0);
      } else {
            *display = pci_resource_start(pdev, 0);
            *registers = pci_resource_start(pdev, 1);
      }

      assert(*display != 0);

      DPRINTK("EXIT\n");
}

static void cirrusfb_pci_unmap(struct fb_info *info)
{
      struct cirrusfb_info *cinfo = info->par;
      struct pci_dev *pdev = cinfo->pdev;

      iounmap(info->screen_base);
#if 0 /* if system didn't claim this region, we would... */
      release_mem_region(0xA0000, 65535);
#endif
      if (release_io_ports)
            release_region(0x3C0, 32);
      pci_release_regions(pdev);
}
#endif /* CONFIG_PCI */

#ifdef CONFIG_ZORRO
static void __devexit cirrusfb_zorro_unmap(struct fb_info *info)
{
      struct cirrusfb_info *cinfo = info->par;
      zorro_release_device(cinfo->zdev);

      if (cinfo->btype == BT_PICASSO4) {
            cinfo->regbase -= 0x600000;
            iounmap((void *)cinfo->regbase);
            iounmap(info->screen_base);
      } else {
            if (zorro_resource_start(cinfo->zdev) > 0x01000000)
                  iounmap(info->screen_base);
      }
}
#endif /* CONFIG_ZORRO */

static int cirrusfb_set_fbinfo(struct fb_info *info)
{
      struct cirrusfb_info *cinfo = info->par;
      struct fb_var_screeninfo *var = &info->var;

      info->pseudo_palette = cinfo->pseudo_palette;
      info->flags = FBINFO_DEFAULT
                | FBINFO_HWACCEL_XPAN
                | FBINFO_HWACCEL_YPAN
                | FBINFO_HWACCEL_FILLRECT
                | FBINFO_HWACCEL_COPYAREA;
      if (noaccel)
            info->flags |= FBINFO_HWACCEL_DISABLED;
      info->fbops = &cirrusfb_ops;
      if (cinfo->btype == BT_GD5480) {
            if (var->bits_per_pixel == 16)
                  info->screen_base += 1 * MB_;
            if (var->bits_per_pixel == 24 || var->bits_per_pixel == 32)
                  info->screen_base += 2 * MB_;
      }

      /* Fill fix common fields */
      strlcpy(info->fix.id, cirrusfb_board_info[cinfo->btype].name,
            sizeof(info->fix.id));

      /* monochrome: only 1 memory plane */
      /* 8 bit and above: Use whole memory area */
      info->fix.smem_len   = info->screen_size;
      if (var->bits_per_pixel == 1)
            info->fix.smem_len /= 4;
      info->fix.type_aux   = 0;
      info->fix.xpanstep   = 1;
      info->fix.ypanstep   = 1;
      info->fix.ywrapstep  = 0;

      /* FIXME: map region at 0xB8000 if available, fill in here */
      info->fix.mmio_len   = 0;
      info->fix.accel = FB_ACCEL_NONE;

      fb_alloc_cmap(&info->cmap, 256, 0);

      return 0;
}

static int cirrusfb_register(struct fb_info *info)
{
      struct cirrusfb_info *cinfo = info->par;
      int err;
      enum cirrus_board btype;

      DPRINTK("ENTER\n");

      printk(KERN_INFO "cirrusfb: Driver for Cirrus Logic based "
            "graphic boards, v" CIRRUSFB_VERSION "\n");

      btype = cinfo->btype;

      /* sanity checks */
      assert(btype != BT_NONE);

      DPRINTK("cirrusfb: (RAM start set to: 0x%p)\n", info->screen_base);

      /* Make pretend we've set the var so our structures are in a "good" */
      /* state, even though we haven't written the mode to the hw yet...  */
      info->var = cirrusfb_predefined[cirrusfb_def_mode].var;
      info->var.activate = FB_ACTIVATE_NOW;

      err = cirrusfb_decode_var(&info->var, &cinfo->currentmode, info);
      if (err < 0) {
            /* should never happen */
            DPRINTK("choking on default var... umm, no good.\n");
            goto err_unmap_cirrusfb;
      }

      /* set all the vital stuff */
      cirrusfb_set_fbinfo(info);

      err = register_framebuffer(info);
      if (err < 0) {
            printk(KERN_ERR "cirrusfb: could not register "
                  "fb device; err = %d!\n", err);
            goto err_dealloc_cmap;
      }

      DPRINTK("EXIT, returning 0\n");
      return 0;

err_dealloc_cmap:
      fb_dealloc_cmap(&info->cmap);
err_unmap_cirrusfb:
      cinfo->unmap(info);
      framebuffer_release(info);
      return err;
}

static void __devexit cirrusfb_cleanup(struct fb_info *info)
{
      struct cirrusfb_info *cinfo = info->par;
      DPRINTK("ENTER\n");

      switch_monitor(cinfo, 0);

      unregister_framebuffer(info);
      fb_dealloc_cmap(&info->cmap);
      printk("Framebuffer unregistered\n");
      cinfo->unmap(info);
      framebuffer_release(info);

      DPRINTK("EXIT\n");
}

#ifdef CONFIG_PCI
static int cirrusfb_pci_register(struct pci_dev *pdev,
                          const struct pci_device_id *ent)
{
      struct cirrusfb_info *cinfo;
      struct fb_info *info;
      enum cirrus_board btype;
      unsigned long board_addr, board_size;
      int ret;

      ret = pci_enable_device(pdev);
      if (ret < 0) {
            printk(KERN_ERR "cirrusfb: Cannot enable PCI device\n");
            goto err_out;
      }

      info = framebuffer_alloc(sizeof(struct cirrusfb_info), &pdev->dev);
      if (!info) {
            printk(KERN_ERR "cirrusfb: could not allocate memory\n");
            ret = -ENOMEM;
            goto err_disable;
      }

      cinfo = info->par;
      cinfo->pdev = pdev;
      cinfo->btype = btype = (enum cirrus_board) ent->driver_data;

      DPRINTK(" Found PCI device, base address 0 is 0x%x, btype set to %d\n",
            pdev->resource[0].start, btype);
      DPRINTK(" base address 1 is 0x%x\n", pdev->resource[1].start);

      if (isPReP) {
            pci_write_config_dword(pdev, PCI_BASE_ADDRESS_0, 0x00000000);
#ifdef CONFIG_PPC_PREP
            get_prep_addrs(&board_addr, &info->fix.mmio_start);
#endif
      /* PReP dies if we ioremap the IO registers, but it works w/out... */
            cinfo->regbase = (char __iomem *) info->fix.mmio_start;
      } else {
            DPRINTK("Attempt to get PCI info for Cirrus Graphics Card\n");
            get_pci_addrs(pdev, &board_addr, &info->fix.mmio_start);
            /* FIXME: this forces VGA.  alternatives? */
            cinfo->regbase = NULL;
      }

      DPRINTK("Board address: 0x%lx, register address: 0x%lx\n",
            board_addr, info->fix.mmio_start);

      board_size = (btype == BT_GD5480) ?
            32 * MB_ : cirrusfb_get_memsize(cinfo->regbase);

      ret = pci_request_regions(pdev, "cirrusfb");
      if (ret < 0) {
            printk(KERN_ERR "cirrusfb: cannot reserve region 0x%lx, "
                   "abort\n",
                   board_addr);
            goto err_release_fb;
      }
#if 0 /* if the system didn't claim this region, we would... */
      if (!request_mem_region(0xA0000, 65535, "cirrusfb")) {
            printk(KERN_ERR "cirrusfb: cannot reserve region 0x%lx, abort\n"
,
                   0xA0000L);
            ret = -EBUSY;
            goto err_release_regions;
      }
#endif
      if (request_region(0x3C0, 32, "cirrusfb"))
            release_io_ports = 1;

      info->screen_base = ioremap(board_addr, board_size);
      if (!info->screen_base) {
            ret = -EIO;
            goto err_release_legacy;
      }

      info->fix.smem_start = board_addr;
      info->screen_size = board_size;
      cinfo->unmap = cirrusfb_pci_unmap;

      printk(KERN_INFO " RAM (%lu kB) at 0xx%lx, ",
            info->screen_size >> 10, board_addr);
      printk(KERN_INFO "Cirrus Logic chipset on PCI bus\n");
      pci_set_drvdata(pdev, info);

      ret = cirrusfb_register(info);
      if (ret)
            iounmap(info->screen_base);
      return ret;

err_release_legacy:
      if (release_io_ports)
            release_region(0x3C0, 32);
#if 0
      release_mem_region(0xA0000, 65535);
err_release_regions:
#endif
      pci_release_regions(pdev);
err_release_fb:
      framebuffer_release(info);
err_disable:
err_out:
      return ret;
}

static void __devexit cirrusfb_pci_unregister(struct pci_dev *pdev)
{
      struct fb_info *info = pci_get_drvdata(pdev);
      DPRINTK("ENTER\n");

      cirrusfb_cleanup(info);

      DPRINTK("EXIT\n");
}

static struct pci_driver cirrusfb_pci_driver = {
      .name       = "cirrusfb",
      .id_table   = cirrusfb_pci_table,
      .probe            = cirrusfb_pci_register,
      .remove           = __devexit_p(cirrusfb_pci_unregister),
#ifdef CONFIG_PM
#if 0
      .suspend    = cirrusfb_pci_suspend,
      .resume           = cirrusfb_pci_resume,
#endif
#endif
};
#endif /* CONFIG_PCI */

#ifdef CONFIG_ZORRO
static int cirrusfb_zorro_register(struct zorro_dev *z,
                           const struct zorro_device_id *ent)
{
      struct cirrusfb_info *cinfo;
      struct fb_info *info;
      enum cirrus_board btype;
      struct zorro_dev *z2 = NULL;
      unsigned long board_addr, board_size, size;
      int ret;

      btype = ent->driver_data;
      if (cirrusfb_zorro_table2[btype].id2)
            z2 = zorro_find_device(cirrusfb_zorro_table2[btype].id2, NULL);
      size = cirrusfb_zorro_table2[btype].size;
      printk(KERN_INFO "cirrusfb: %s board detected; ",
             cirrusfb_board_info[btype].name);

      info = framebuffer_alloc(sizeof(struct cirrusfb_info), &z->dev);
      if (!info) {
            printk(KERN_ERR "cirrusfb: could not allocate memory\n");
            ret = -ENOMEM;
            goto err_out;
      }

      cinfo = info->par;
      cinfo->btype = btype;

      assert(z);
      assert(btype != BT_NONE);

      cinfo->zdev = z;
      board_addr = zorro_resource_start(z);
      board_size = zorro_resource_len(z);
      info->screen_size = size;

      if (!zorro_request_device(z, "cirrusfb")) {
            printk(KERN_ERR "cirrusfb: cannot reserve region 0x%lx, "
                   "abort\n",
                   board_addr);
            ret = -EBUSY;
            goto err_release_fb;
      }

      printk(" RAM (%lu MB) at $%lx, ", board_size / MB_, board_addr);

      ret = -EIO;

      if (btype == BT_PICASSO4) {
            printk(KERN_INFO " REG at $%lx\n", board_addr + 0x600000);

            /* To be precise, for the P4 this is not the */
            /* begin of the board, but the begin of RAM. */
            /* for P4, map in its address space in 2 chunks (### TEST! ) */
            /* (note the ugly hardcoded 16M number) */
            cinfo->regbase = ioremap(board_addr, 16777216);
            if (!cinfo->regbase)
                  goto err_release_region;

            DPRINTK("cirrusfb: Virtual address for board set to: $%p\n",
                  cinfo->regbase);
            cinfo->regbase += 0x600000;
            info->fix.mmio_start = board_addr + 0x600000;

            info->fix.smem_start = board_addr + 16777216;
            info->screen_base = ioremap(info->fix.smem_start, 16777216);
            if (!info->screen_base)
                  goto err_unmap_regbase;
      } else {
            printk(KERN_INFO " REG at $%lx\n",
                  (unsigned long) z2->resource.start);

            info->fix.smem_start = board_addr;
            if (board_addr > 0x01000000)
                  info->screen_base = ioremap(board_addr, board_size);
            else
                  info->screen_base = (caddr_t) ZTWO_VADDR(board_addr);
            if (!info->screen_base)
                  goto err_release_region;

            /* set address for REG area of board */
            cinfo->regbase = (caddr_t) ZTWO_VADDR(z2->resource.start);
            info->fix.mmio_start = z2->resource.start;

            DPRINTK("cirrusfb: Virtual address for board set to: $%p\n",
                  cinfo->regbase);
      }
      cinfo->unmap = cirrusfb_zorro_unmap;

      printk(KERN_INFO "Cirrus Logic chipset on Zorro bus\n");
      zorro_set_drvdata(z, info);

      ret = cirrusfb_register(info);
      if (ret) {
            if (btype == BT_PICASSO4) {
                  iounmap(info->screen_base);
                  iounmap(cinfo->regbase - 0x600000);
            } else if (board_addr > 0x01000000)
                  iounmap(info->screen_base);
      }
      return ret;

err_unmap_regbase:
      /* Parental advisory: explicit hack */
      iounmap(cinfo->regbase - 0x600000);
err_release_region:
      release_region(board_addr, board_size);
err_release_fb:
      framebuffer_release(info);
err_out:
      return ret;
}

void __devexit cirrusfb_zorro_unregister(struct zorro_dev *z)
{
      struct fb_info *info = zorro_get_drvdata(z);
      DPRINTK("ENTER\n");

      cirrusfb_cleanup(info);

      DPRINTK("EXIT\n");
}

static struct zorro_driver cirrusfb_zorro_driver = {
      .name       = "cirrusfb",
      .id_table   = cirrusfb_zorro_table,
      .probe            = cirrusfb_zorro_register,
      .remove           = __devexit_p(cirrusfb_zorro_unregister),
};
#endif /* CONFIG_ZORRO */

static int __init cirrusfb_init(void)
{
      int error = 0;

#ifndef MODULE
      char *option = NULL;

      if (fb_get_options("cirrusfb", &option))
            return -ENODEV;
      cirrusfb_setup(option);
#endif

#ifdef CONFIG_ZORRO
      error |= zorro_register_driver(&cirrusfb_zorro_driver);
#endif
#ifdef CONFIG_PCI
      error |= pci_register_driver(&cirrusfb_pci_driver);
#endif
      return error;
}

#ifndef MODULE
static int __init cirrusfb_setup(char *options) {
      char *this_opt, s[32];
      int i;

      DPRINTK("ENTER\n");

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

      while ((this_opt = strsep(&options, ",")) != NULL) {
            if (!*this_opt) continue;

            DPRINTK("cirrusfb_setup: option '%s'\n", this_opt);

            for (i = 0; i < NUM_TOTAL_MODES; i++) {
                  sprintf(s, "mode:%s", cirrusfb_predefined[i].name);
                  if (strcmp(this_opt, s) == 0)
                        cirrusfb_def_mode = i;
            }
            if (!strcmp(this_opt, "noaccel"))
                  noaccel = 1;
      }
      return 0;
}
#endif

    /*
     *  Modularization
     */

MODULE_AUTHOR("Copyright 1999,2000 Jeff Garzik <jgarzik@pobox.com>");
MODULE_DESCRIPTION("Accelerated FBDev driver for Cirrus Logic chips");
MODULE_LICENSE("GPL");

static void __exit cirrusfb_exit(void)
{
#ifdef CONFIG_PCI
      pci_unregister_driver(&cirrusfb_pci_driver);
#endif
#ifdef CONFIG_ZORRO
      zorro_unregister_driver(&cirrusfb_zorro_driver);
#endif
}

module_init(cirrusfb_init);

#ifdef MODULE
module_exit(cirrusfb_exit);
#endif

/**********************************************************************/
/* about the following functions - I have used the same names for the */
/* functions as Markus Wild did in his Retina driver for NetBSD as    */
/* they just made sense for this purpose. Apart from that, I wrote    */
/* these functions myself.                                */
/**********************************************************************/

/*** WGen() - write into one of the external/general registers ***/
static void WGen(const struct cirrusfb_info *cinfo,
              int regnum, unsigned char val)
{
      unsigned long regofs = 0;

      if (cinfo->btype == BT_PICASSO) {
            /* Picasso II specific hack */
/*          if (regnum == VGA_PEL_IR || regnum == VGA_PEL_D ||
              regnum == CL_VSSM2) */
            if (regnum == VGA_PEL_IR || regnum == VGA_PEL_D)
                  regofs = 0xfff;
      }

      vga_w(cinfo->regbase, regofs + regnum, val);
}

/*** RGen() - read out one of the external/general registers ***/
static unsigned char RGen(const struct cirrusfb_info *cinfo, int regnum)
{
      unsigned long regofs = 0;

      if (cinfo->btype == BT_PICASSO) {
            /* Picasso II specific hack */
/*          if (regnum == VGA_PEL_IR || regnum == VGA_PEL_D ||
              regnum == CL_VSSM2) */
            if (regnum == VGA_PEL_IR || regnum == VGA_PEL_D)
                  regofs = 0xfff;
      }

      return vga_r(cinfo->regbase, regofs + regnum);
}

/*** AttrOn() - turn on VideoEnable for Attribute controller ***/
static void AttrOn(const struct cirrusfb_info *cinfo)
{
      assert(cinfo != NULL);

      DPRINTK("ENTER\n");

      if (vga_rcrt(cinfo->regbase, CL_CRT24) & 0x80) {
            /* if we're just in "write value" mode, write back the */
            /* same value as before to not modify anything */
            vga_w(cinfo->regbase, VGA_ATT_IW,
                  vga_r(cinfo->regbase, VGA_ATT_R));
      }
      /* turn on video bit */
/*      vga_w(cinfo->regbase, VGA_ATT_IW, 0x20); */
      vga_w(cinfo->regbase, VGA_ATT_IW, 0x33);

      /* dummy write on Reg0 to be on "write index" mode next time */
      vga_w(cinfo->regbase, VGA_ATT_IW, 0x00);

      DPRINTK("EXIT\n");
}

/*** WHDR() - write into the Hidden DAC register ***/
/* as the HDR is the only extension register that requires special treatment
 * (the other extension registers are accessible just like the "ordinary"
 * registers of their functional group) here is a specialized routine for
 * accessing the HDR
 */
static void WHDR(const struct cirrusfb_info *cinfo, unsigned char val)
{
      unsigned char dummy;

      if (cinfo->btype == BT_PICASSO) {
            /* Klaus' hint for correct access to HDR on some boards */
            /* first write 0 to pixel mask (3c6) */
            WGen(cinfo, VGA_PEL_MSK, 0x00);
            udelay(200);
            /* next read dummy from pixel address (3c8) */
            dummy = RGen(cinfo, VGA_PEL_IW);
            udelay(200);
      }
      /* now do the usual stuff to access the HDR */

      dummy = RGen(cinfo, VGA_PEL_MSK);
      udelay(200);
      dummy = RGen(cinfo, VGA_PEL_MSK);
      udelay(200);
      dummy = RGen(cinfo, VGA_PEL_MSK);
      udelay(200);
      dummy = RGen(cinfo, VGA_PEL_MSK);
      udelay(200);

      WGen(cinfo, VGA_PEL_MSK, val);
      udelay(200);

      if (cinfo->btype == BT_PICASSO) {
            /* now first reset HDR access counter */
            dummy = RGen(cinfo, VGA_PEL_IW);
            udelay(200);

            /* and at the end, restore the mask value */
            /* ## is this mask always 0xff? */
            WGen(cinfo, VGA_PEL_MSK, 0xff);
            udelay(200);
      }
}

/*** WSFR() - write to the "special function register" (SFR) ***/
static void WSFR(struct cirrusfb_info *cinfo, unsigned char val)
{
#ifdef CONFIG_ZORRO
      assert(cinfo->regbase != NULL);
      cinfo->SFR = val;
      z_writeb(val, cinfo->regbase + 0x8000);
#endif
}

/* The Picasso has a second register for switching the monitor bit */
static void WSFR2(struct cirrusfb_info *cinfo, unsigned char val)
{
#ifdef CONFIG_ZORRO
      /* writing an arbitrary value to this one causes the monitor switcher */
      /* to flip to Amiga display */
      assert(cinfo->regbase != NULL);
      cinfo->SFR = val;
      z_writeb(val, cinfo->regbase + 0x9000);
#endif
}

/*** WClut - set CLUT entry (range: 0..63) ***/
static void WClut(struct cirrusfb_info *cinfo, unsigned char regnum, unsigned char red,
          unsigned char green, unsigned char blue)
{
      unsigned int data = VGA_PEL_D;

      /* address write mode register is not translated.. */
      vga_w(cinfo->regbase, VGA_PEL_IW, regnum);

      if (cinfo->btype == BT_PICASSO || cinfo->btype == BT_PICASSO4 ||
          cinfo->btype == BT_ALPINE || cinfo->btype == BT_GD5480) {
            /* but DAC data register IS, at least for Picasso II */
            if (cinfo->btype == BT_PICASSO)
                  data += 0xfff;
            vga_w(cinfo->regbase, data, red);
            vga_w(cinfo->regbase, data, green);
            vga_w(cinfo->regbase, data, blue);
      } else {
            vga_w(cinfo->regbase, data, blue);
            vga_w(cinfo->regbase, data, green);
            vga_w(cinfo->regbase, data, red);
      }
}

#if 0
/*** RClut - read CLUT entry (range 0..63) ***/
static void RClut(struct cirrusfb_info *cinfo, unsigned char regnum, unsigned char *red,
          unsigned char *green, unsigned char *blue)
{
      unsigned int data = VGA_PEL_D;

      vga_w(cinfo->regbase, VGA_PEL_IR, regnum);

      if (cinfo->btype == BT_PICASSO || cinfo->btype == BT_PICASSO4 ||
          cinfo->btype == BT_ALPINE || cinfo->btype == BT_GD5480) {
            if (cinfo->btype == BT_PICASSO)
                  data += 0xfff;
            *red = vga_r(cinfo->regbase, data);
            *green = vga_r(cinfo->regbase, data);
            *blue = vga_r(cinfo->regbase, data);
      } else {
            *blue = vga_r(cinfo->regbase, data);
            *green = vga_r(cinfo->regbase, data);
            *red = vga_r(cinfo->regbase, data);
      }
}
#endif

/*******************************************************************
      cirrusfb_WaitBLT()

      Wait for the BitBLT engine to complete a possible earlier job
*********************************************************************/

/* FIXME: use interrupts instead */
static void cirrusfb_WaitBLT(u8 __iomem *regbase)
{
      /* now busy-wait until we're done */
      while (vga_rgfx(regbase, CL_GR31) & 0x08)
            /* do nothing */ ;
}

/*******************************************************************
      cirrusfb_BitBLT()

      perform accelerated "scrolling"
********************************************************************/

static void cirrusfb_BitBLT(u8 __iomem *regbase, int bits_per_pixel,
                      u_short curx, u_short cury,
                      u_short destx, u_short desty,
                      u_short width, u_short height,
                      u_short line_length)
{
      u_short nwidth, nheight;
      u_long nsrc, ndest;
      u_char bltmode;

      DPRINTK("ENTER\n");

      nwidth = width - 1;
      nheight = height - 1;

      bltmode = 0x00;
      /* if source adr < dest addr, do the Blt backwards */
      if (cury <= desty) {
            if (cury == desty) {
                  /* if src and dest are on the same line, check x */
                  if (curx < destx)
                        bltmode |= 0x01;
            } else
                  bltmode |= 0x01;
      }
      if (!bltmode) {
            /* standard case: forward blitting */
            nsrc = (cury * line_length) + curx;
            ndest = (desty * line_length) + destx;
      } else {
            /* this means start addresses are at the end,
             * counting backwards
             */
            nsrc = cury * line_length + curx +
                  nheight * line_length + nwidth;
            ndest = desty * line_length + destx +
                  nheight * line_length + nwidth;
      }

      /*
         run-down of registers to be programmed:
         destination pitch
         source pitch
         BLT width/height
         source start
         destination start
         BLT mode
         BLT ROP
         VGA_GFX_SR_VALUE / VGA_GFX_SR_ENABLE: "fill color"
         start/stop
       */

      cirrusfb_WaitBLT(regbase);

      /* pitch: set to line_length */
      /* dest pitch low */
      vga_wgfx(regbase, CL_GR24, line_length & 0xff);
      /* dest pitch hi */
      vga_wgfx(regbase, CL_GR25, line_length >> 8);
      /* source pitch low */
      vga_wgfx(regbase, CL_GR26, line_length & 0xff);
      /* source pitch hi */
      vga_wgfx(regbase, CL_GR27, line_length >> 8);

      /* BLT width: actual number of pixels - 1 */
      /* BLT width low */
      vga_wgfx(regbase, CL_GR20, nwidth & 0xff);
      /* BLT width hi */
      vga_wgfx(regbase, CL_GR21, nwidth >> 8);

      /* BLT height: actual number of lines -1 */
      /* BLT height low */
      vga_wgfx(regbase, CL_GR22, nheight & 0xff);
      /* BLT width hi */
      vga_wgfx(regbase, CL_GR23, nheight >> 8);

      /* BLT destination */
      /* BLT dest low */
      vga_wgfx(regbase, CL_GR28, (u_char) (ndest & 0xff));
      /* BLT dest mid */
      vga_wgfx(regbase, CL_GR29, (u_char) (ndest >> 8));
      /* BLT dest hi */
      vga_wgfx(regbase, CL_GR2A, (u_char) (ndest >> 16));

      /* BLT source */
      /* BLT src low */
      vga_wgfx(regbase, CL_GR2C, (u_char) (nsrc & 0xff));
      /* BLT src mid */
      vga_wgfx(regbase, CL_GR2D, (u_char) (nsrc >> 8));
      /* BLT src hi */
      vga_wgfx(regbase, CL_GR2E, (u_char) (nsrc >> 16));

      /* BLT mode */
      vga_wgfx(regbase, CL_GR30, bltmode);      /* BLT mode */

      /* BLT ROP: SrcCopy */
      vga_wgfx(regbase, CL_GR32, 0x0d);   /* BLT ROP */

      /* and finally: GO! */
      vga_wgfx(regbase, CL_GR31, 0x02);   /* BLT Start/status */

      DPRINTK("EXIT\n");
}

/*******************************************************************
      cirrusfb_RectFill()

      perform accelerated rectangle fill
********************************************************************/

static void cirrusfb_RectFill(u8 __iomem *regbase, int bits_per_pixel,
                 u_short x, u_short y, u_short width, u_short height,
                 u_char color, u_short line_length)
{
      u_short nwidth, nheight;
      u_long ndest;
      u_char op;

      DPRINTK("ENTER\n");

      nwidth = width - 1;
      nheight = height - 1;

      ndest = (y * line_length) + x;

      cirrusfb_WaitBLT(regbase);

      /* pitch: set to line_length */
      vga_wgfx(regbase, CL_GR24, line_length & 0xff); /* dest pitch low */
      vga_wgfx(regbase, CL_GR25, line_length >> 8);   /* dest pitch hi */
      vga_wgfx(regbase, CL_GR26, line_length & 0xff); /* source pitch low */
      vga_wgfx(regbase, CL_GR27, line_length >> 8);   /* source pitch hi */

      /* BLT width: actual number of pixels - 1 */
      vga_wgfx(regbase, CL_GR20, nwidth & 0xff);      /* BLT width low */
      vga_wgfx(regbase, CL_GR21, nwidth >> 8);  /* BLT width hi */

      /* BLT height: actual number of lines -1 */
      vga_wgfx(regbase, CL_GR22, nheight & 0xff);     /* BLT height low */
      vga_wgfx(regbase, CL_GR23, nheight >> 8); /* BLT width hi */

      /* BLT destination */
      /* BLT dest low */
      vga_wgfx(regbase, CL_GR28, (u_char) (ndest & 0xff));
      /* BLT dest mid */
      vga_wgfx(regbase, CL_GR29, (u_char) (ndest >> 8));
      /* BLT dest hi */
      vga_wgfx(regbase, CL_GR2A, (u_char) (ndest >> 16));

      /* BLT source: set to 0 (is a dummy here anyway) */
      vga_wgfx(regbase, CL_GR2C, 0x00);   /* BLT src low */
      vga_wgfx(regbase, CL_GR2D, 0x00);   /* BLT src mid */
      vga_wgfx(regbase, CL_GR2E, 0x00);   /* BLT src hi */

      /* This is a ColorExpand Blt, using the */
      /* same color for foreground and background */
      vga_wgfx(regbase, VGA_GFX_SR_VALUE, color);     /* foreground color */
      vga_wgfx(regbase, VGA_GFX_SR_ENABLE, color);    /* background color */

      op = 0xc0;
      if (bits_per_pixel == 16) {
            vga_wgfx(regbase, CL_GR10, color);  /* foreground color */
            vga_wgfx(regbase, CL_GR11, color);  /* background color */
            op = 0x50;
            op = 0xd0;
      } else if (bits_per_pixel == 32) {
            vga_wgfx(regbase, CL_GR10, color);  /* foreground color */
            vga_wgfx(regbase, CL_GR11, color);  /* background color */
            vga_wgfx(regbase, CL_GR12, color);  /* foreground color */
            vga_wgfx(regbase, CL_GR13, color);  /* background color */
            vga_wgfx(regbase, CL_GR14, 0);      /* foreground color */
            vga_wgfx(regbase, CL_GR15, 0);      /* background color */
            op = 0x50;
            op = 0xf0;
      }
      /* BLT mode: color expand, Enable 8x8 copy (faster?) */
      vga_wgfx(regbase, CL_GR30, op);     /* BLT mode */

      /* BLT ROP: SrcCopy */
      vga_wgfx(regbase, CL_GR32, 0x0d);   /* BLT ROP */

      /* and finally: GO! */
      vga_wgfx(regbase, CL_GR31, 0x02);   /* BLT Start/status */

      DPRINTK("EXIT\n");
}

/**************************************************************************
 * bestclock() - determine closest possible clock lower(?) than the
 * desired pixel clock
 **************************************************************************/
static void bestclock(long freq, long *best, long *nom,
                   long *den, long *div, long maxfreq)
{
      long n, h, d, f;

      assert(best != NULL);
      assert(nom != NULL);
      assert(den != NULL);
      assert(div != NULL);
      assert(maxfreq > 0);

      *nom = 0;
      *den = 0;
      *div = 0;

      DPRINTK("ENTER\n");

      if (freq < 8000)
            freq = 8000;

      if (freq > maxfreq)
            freq = maxfreq;

      *best = 0;
      f = freq * 10;

      for (n = 32; n < 128; n++) {
            d = (143181 * n) / f;
            if ((d >= 7) && (d <= 63)) {
                  if (d > 31)
                        d = (d / 2) * 2;
                  h = (14318 * n) / d;
                  if (abs(h - freq) < abs(*best - freq)) {
                        *best = h;
                        *nom = n;
                        if (d < 32) {
                              *den = d;
                              *div = 0;
                        } else {
                              *den = d / 2;
                              *div = 1;
                        }
                  }
            }
            d = ((143181 * n) + f - 1) / f;
            if ((d >= 7) && (d <= 63)) {
                  if (d > 31)
                        d = (d / 2) * 2;
                  h = (14318 * n) / d;
                  if (abs(h - freq) < abs(*best - freq)) {
                        *best = h;
                        *nom = n;
                        if (d < 32) {
                              *den = d;
                              *div = 0;
                        } else {
                              *den = d / 2;
                              *div = 1;
                        }
                  }
            }
      }

      DPRINTK("Best possible values for given frequency:\n");
      DPRINTK("   best: %ld kHz  nom: %ld  den: %ld  div: %ld\n",
            freq, *nom, *den, *div);

      DPRINTK("EXIT\n");
}

/* -------------------------------------------------------------------------
 *
 * debugging functions
 *
 * -------------------------------------------------------------------------
 */

#ifdef CIRRUSFB_DEBUG

/**
 * cirrusfb_dbg_print_byte
 * @name: name associated with byte value to be displayed
 * @val: byte value to be displayed
 *
 * DESCRIPTION:
 * Display an indented string, along with a hexidecimal byte value, and
 * its decoded bits.  Bits 7 through 0 are listed in left-to-right
 * order.
 */

static
void cirrusfb_dbg_print_byte(const char *name, unsigned char val)
{
      DPRINTK("%8s = 0x%02X (bits 7-0: %c%c%c%c%c%c%c%c)\n",
            name, val,
            val & 0x80 ? '1' : '0',
            val & 0x40 ? '1' : '0',
            val & 0x20 ? '1' : '0',
            val & 0x10 ? '1' : '0',
            val & 0x08 ? '1' : '0',
            val & 0x04 ? '1' : '0',
            val & 0x02 ? '1' : '0',
            val & 0x01 ? '1' : '0');
}

/**
 * cirrusfb_dbg_print_regs
 * @base: If using newmmio, the newmmio base address, otherwise %NULL
 * @reg_class: type of registers to read: %CRT, or %SEQ
 *
 * DESCRIPTION:
 * Dumps the given list of VGA CRTC registers.  If @base is %NULL,
 * old-style I/O ports are queried for information, otherwise MMIO is
 * used at the given @base address to query the information.
 */

static
void cirrusfb_dbg_print_regs(caddr_t regbase,
                       enum cirrusfb_dbg_reg_class reg_class, ...)
{
      va_list list;
      unsigned char val = 0;
      unsigned reg;
      char *name;

      va_start(list, reg_class);

      name = va_arg(list, char *);
      while (name != NULL) {
            reg = va_arg(list, int);

            switch (reg_class) {
            case CRT:
                  val = vga_rcrt(regbase, (unsigned char) reg);
                  break;
            case SEQ:
                  val = vga_rseq(regbase, (unsigned char) reg);
                  break;
            default:
                  /* should never occur */
                  assert(false);
                  break;
            }

            cirrusfb_dbg_print_byte(name, val);

            name = va_arg(list, char *);
      }

      va_end(list);
}

/**
 * cirrusfb_dump
 * @cirrusfbinfo:
 *
 * DESCRIPTION:
 */

static void cirrusfb_dump(void)
{
      cirrusfb_dbg_reg_dump(NULL);
}

/**
 * cirrusfb_dbg_reg_dump
 * @base: If using newmmio, the newmmio base address, otherwise %NULL
 *
 * DESCRIPTION:
 * Dumps a list of interesting VGA and CIRRUSFB registers.  If @base is %NULL,
 * old-style I/O ports are queried for information, otherwise MMIO is
 * used at the given @base address to query the information.
 */

static
void cirrusfb_dbg_reg_dump(caddr_t regbase)
{
      DPRINTK("CIRRUSFB VGA CRTC register dump:\n");

      cirrusfb_dbg_print_regs(regbase, CRT,
                     "CR00", 0x00,
                     "CR01", 0x01,
                     "CR02", 0x02,
                     "CR03", 0x03,
                     "CR04", 0x04,
                     "CR05", 0x05,
                     "CR06", 0x06,
                     "CR07", 0x07,
                     "CR08", 0x08,
                     "CR09", 0x09,
                     "CR0A", 0x0A,
                     "CR0B", 0x0B,
                     "CR0C", 0x0C,
                     "CR0D", 0x0D,
                     "CR0E", 0x0E,
                     "CR0F", 0x0F,
                     "CR10", 0x10,
                     "CR11", 0x11,
                     "CR12", 0x12,
                     "CR13", 0x13,
                     "CR14", 0x14,
                     "CR15", 0x15,
                     "CR16", 0x16,
                     "CR17", 0x17,
                     "CR18", 0x18,
                     "CR22", 0x22,
                     "CR24", 0x24,
                     "CR26", 0x26,
                     "CR2D", 0x2D,
                     "CR2E", 0x2E,
                     "CR2F", 0x2F,
                     "CR30", 0x30,
                     "CR31", 0x31,
                     "CR32", 0x32,
                     "CR33", 0x33,
                     "CR34", 0x34,
                     "CR35", 0x35,
                     "CR36", 0x36,
                     "CR37", 0x37,
                     "CR38", 0x38,
                     "CR39", 0x39,
                     "CR3A", 0x3A,
                     "CR3B", 0x3B,
                     "CR3C", 0x3C,
                     "CR3D", 0x3D,
                     "CR3E", 0x3E,
                     "CR3F", 0x3F,
                     NULL);

      DPRINTK("\n");

      DPRINTK("CIRRUSFB VGA SEQ register dump:\n");

      cirrusfb_dbg_print_regs(regbase, SEQ,
                     "SR00", 0x00,
                     "SR01", 0x01,
                     "SR02", 0x02,
                     "SR03", 0x03,
                     "SR04", 0x04,
                     "SR08", 0x08,
                     "SR09", 0x09,
                     "SR0A", 0x0A,
                     "SR0B", 0x0B,
                     "SR0D", 0x0D,
                     "SR10", 0x10,
                     "SR11", 0x11,
                     "SR12", 0x12,
                     "SR13", 0x13,
                     "SR14", 0x14,
                     "SR15", 0x15,
                     "SR16", 0x16,
                     "SR17", 0x17,
                     "SR18", 0x18,
                     "SR19", 0x19,
                     "SR1A", 0x1A,
                     "SR1B", 0x1B,
                     "SR1C", 0x1C,
                     "SR1D", 0x1D,
                     "SR1E", 0x1E,
                     "SR1F", 0x1F,
                     NULL);

      DPRINTK("\n");
}

#endif                        /* CIRRUSFB_DEBUG */


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