/*
 *  controlfb.c -- frame buffer device for the PowerMac 'control' display
 *
 *  Created 12 July 1998 by Dan Jacobowitz <dan@debian.org>
 *  Copyright (C) 1998 Dan Jacobowitz
 *  Copyright (C) 2001 Takashi Oe
 *
 *  Mmap code by Michel Lanners <mlan@cpu.lu>
 *
 *  Frame buffer structure from:
 *    drivers/video/chipsfb.c -- frame buffer device for
 *    Chips & Technologies 65550 chip.
 *
 *    Copyright (C) 1998 Paul Mackerras
 *
 *    This file is derived from the Powermac "chips" driver:
 *    Copyright (C) 1997 Fabio Riccardi.
 *    And from the frame buffer device for Open Firmware-initialized devices:
 *    Copyright (C) 1997 Geert Uytterhoeven.
 *
 *  Hardware information from:
 *    control.c: Console support for PowerMac "control" display adaptor.
 *    Copyright (C) 1996 Paul Mackerras
 *
 *  Updated to 2.5 framebuffer API by Ben Herrenschmidt
 *  <benh@kernel.crashing.org>, Paul Mackerras <paulus@samba.org>,
 *  and James Simmons <jsimmons@infradead.org>.
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License. See the file COPYING in the main directory of this archive for
 *  more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/nvram.h>
#include <linux/adb.h>
#include <linux/cuda.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/pgtable.h>
#include <asm/btext.h>

#include "macmodes.h"
#include "controlfb.h"

struct fb_par_control {
        int     vmode, cmode;
        int     xres, yres;
        int     vxres, vyres;
        int     xoffset, yoffset;
        int     pitch;
        struct control_regvals  regvals;
        unsigned long sync;
        unsigned char ctrl;
};

#define DIRTY(z) ((x)->z != (y)->z)
#define DIRTY_CMAP(z) (memcmp(&((x)->z), &((y)->z), sizeof((y)->z)))
static inline int PAR_EQUAL(struct fb_par_control *x, struct fb_par_control *y)
{
        int i, results;

        results = 1;
        for (i = 0; i < 3; i++)
                results &= !DIRTY(regvals.clock_params[i]);
        if (!results)
                return 0;
        for (i = 0; i < 16; i++)
                results &= !DIRTY(regvals.regs[i]);
        if (!results)
                return 0;
        return (!DIRTY(cmode) && !DIRTY(xres) && !DIRTY(yres)
                && !DIRTY(vxres) && !DIRTY(vyres));
}
static inline int VAR_MATCH(struct fb_var_screeninfo *x, struct fb_var_screeninfo *y)
{
        return (!DIRTY(bits_per_pixel) && !DIRTY(xres)
                && !DIRTY(yres) && !DIRTY(xres_virtual)
                && !DIRTY(yres_virtual)
                && !DIRTY_CMAP(red) && !DIRTY_CMAP(green) && !DIRTY_CMAP(blue));
}

struct fb_info_control {
        struct fb_info          info;
        struct fb_par_control   par;
        u32                     pseudo_palette[16];
                
        struct cmap_regs        __iomem *cmap_regs;
        unsigned long           cmap_regs_phys;
        
        struct control_regs     __iomem *control_regs;
        unsigned long           control_regs_phys;
        unsigned long           control_regs_size;
        
        __u8                    __iomem *frame_buffer;
        unsigned long           frame_buffer_phys;
        unsigned long           fb_orig_base;
        unsigned long           fb_orig_size;

        int                     control_use_bank2;
        unsigned long           total_vram;
        unsigned char           vram_attr;
};

/* control register access macro */
#define CNTRL_REG(INFO,REG) (&(((INFO)->control_regs->REG).r))


/******************** Prototypes for exported functions ********************/
/*
 * struct fb_ops
 */
static int controlfb_pan_display(struct fb_var_screeninfo *var,
        struct fb_info *info);
static int controlfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
        u_int transp, struct fb_info *info);
static int controlfb_blank(int blank_mode, struct fb_info *info);
static int controlfb_mmap(struct fb_info *info,
        struct vm_area_struct *vma);
static int controlfb_set_par (struct fb_info *info);
static int controlfb_check_var (struct fb_var_screeninfo *var, struct fb_info *info);

/******************** Prototypes for internal functions **********************/

static void set_control_clock(unsigned char *params);
static int init_control(struct fb_info_control *p);
static void control_set_hardware(struct fb_info_control *p,
        struct fb_par_control *par);
static int control_of_init(struct device_node *dp);
static void find_vram_size(struct fb_info_control *p);
static int read_control_sense(struct fb_info_control *p);
static int calc_clock_params(unsigned long clk, unsigned char *param);
static int control_var_to_par(struct fb_var_screeninfo *var,
        struct fb_par_control *par, const struct fb_info *fb_info);
static inline void control_par_to_var(struct fb_par_control *par,
        struct fb_var_screeninfo *var);
static void control_init_info(struct fb_info *info, struct fb_info_control *p);
static void control_cleanup(void);


/************************** Internal variables *******************************/

static struct fb_info_control *control_fb;

static int default_vmode __initdata = VMODE_NVRAM;
static int default_cmode __initdata = CMODE_NVRAM;


static struct fb_ops controlfb_ops = {
        .owner          = THIS_MODULE,
        .fb_check_var   = controlfb_check_var,
        .fb_set_par     = controlfb_set_par,
        .fb_setcolreg   = controlfb_setcolreg,
        .fb_pan_display = controlfb_pan_display,
        .fb_blank       = controlfb_blank,
        .fb_mmap        = controlfb_mmap,
        .fb_fillrect    = cfb_fillrect,
        .fb_copyarea    = cfb_copyarea,
        .fb_imageblit   = cfb_imageblit,
};


/********************  The functions for controlfb_ops ********************/

#ifdef MODULE
MODULE_LICENSE("GPL");

int init_module(void)
{
        struct device_node *dp;
        int ret = -ENXIO;

        dp = of_find_node_by_name(NULL, "control");
        if (dp != 0 && !control_of_init(dp))
                ret = 0;
        of_node_put(dp);

        return ret;
}

void cleanup_module(void)
{
        control_cleanup();
}
#endif

/*
 * Checks a var structure
 */
static int controlfb_check_var (struct fb_var_screeninfo *var, struct fb_info *info)
{
        struct fb_par_control par;
        int err;

        err = control_var_to_par(var, &par, info);
        if (err)
                return err;     
        control_par_to_var(&par, var);

        return 0;
}

/*
 * Applies current var to display
 */
static int controlfb_set_par (struct fb_info *info)
{
        struct fb_info_control *p =
                container_of(info, struct fb_info_control, info);
        struct fb_par_control par;
        int err;

        if((err = control_var_to_par(&info->var, &par, info))) {
                printk (KERN_ERR "controlfb_set_par: error calling"
                                 " control_var_to_par: %d.\n", err);
                return err;
        }
        
        control_set_hardware(p, &par);

        info->fix.visual = (p->par.cmode == CMODE_8) ?
                FB_VISUAL_PSEUDOCOLOR : FB_VISUAL_DIRECTCOLOR;
        info->fix.line_length = p->par.pitch;
        info->fix.xpanstep = 32 >> p->par.cmode;
        info->fix.ypanstep = 1;

        return 0;
}

/*
 * Set screen start address according to var offset values
 */
static inline void set_screen_start(int xoffset, int yoffset,
        struct fb_info_control *p)
{
        struct fb_par_control *par = &p->par;

        par->xoffset = xoffset;
        par->yoffset = yoffset;
        out_le32(CNTRL_REG(p,start_addr),
                 par->yoffset * par->pitch + (par->xoffset << par->cmode));
}


static int controlfb_pan_display(struct fb_var_screeninfo *var,
                                 struct fb_info *info)
{
        unsigned int xoffset, hstep;
        struct fb_info_control *p =
                container_of(info, struct fb_info_control, info);
        struct fb_par_control *par = &p->par;

        /*
         * make sure start addr will be 32-byte aligned
         */
        hstep = 0x1f >> par->cmode;
        xoffset = (var->xoffset + hstep) & ~hstep;

        if (xoffset+par->xres > par->vxres ||
            var->yoffset+par->yres > par->vyres)
                return -EINVAL;

        set_screen_start(xoffset, var->yoffset, p);

        return 0;
}


/*
 * Private mmap since we want to have a different caching on the framebuffer
 * for controlfb.
 * Note there's no locking in here; it's done in fb_mmap() in fbmem.c.
 */
static int controlfb_mmap(struct fb_info *info,
                       struct vm_area_struct *vma)
{
        unsigned long mmio_pgoff;
        unsigned long start;
        u32 len;

        start = info->fix.smem_start;
        len = info->fix.smem_len;
        mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;
        if (vma->vm_pgoff >= mmio_pgoff) {
                if (info->var.accel_flags)
                        return -EINVAL;
                vma->vm_pgoff -= mmio_pgoff;
                start = info->fix.mmio_start;
                len = info->fix.mmio_len;
                vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
        } else {
                /* framebuffer */
                vma->vm_page_prot = pgprot_cached_wthru(vma->vm_page_prot);
        }

        return vm_iomap_memory(vma, start, len);
}

static int controlfb_blank(int blank_mode, struct fb_info *info)
{
        struct fb_info_control *p =
                container_of(info, struct fb_info_control, info);
        unsigned ctrl;

        ctrl = le32_to_cpup(CNTRL_REG(p,ctrl));
        if (blank_mode > 0)
                switch (blank_mode) {
                case FB_BLANK_VSYNC_SUSPEND:
                        ctrl &= ~3;
                        break;
                case FB_BLANK_HSYNC_SUSPEND:
                        ctrl &= ~0x30;
                        break;
                case FB_BLANK_POWERDOWN:
                        ctrl &= ~0x33;
                        /* fall through */
                case FB_BLANK_NORMAL:
                        ctrl |= 0x400;
                        break;
                default:
                        break;
                }
        else {
                ctrl &= ~0x400;
                ctrl |= 0x33;
        }
        out_le32(CNTRL_REG(p,ctrl), ctrl);

        return 0;
}

static int controlfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
                             u_int transp, struct fb_info *info)
{
        struct fb_info_control *p =
                container_of(info, struct fb_info_control, info);
        __u8 r, g, b;

        if (regno > 255)
                return 1;

        r = red >> 8;
        g = green >> 8;
        b = blue >> 8;

        out_8(&p->cmap_regs->addr, regno);      /* tell clut what addr to fill  */
        out_8(&p->cmap_regs->lut, r);           /* send one color channel at    */
        out_8(&p->cmap_regs->lut, g);           /* a time...                    */
        out_8(&p->cmap_regs->lut, b);

        if (regno < 16) {
                int i;
                switch (p->par.cmode) {
                case CMODE_16:
                        p->pseudo_palette[regno] =
                            (regno << 10) | (regno << 5) | regno;
                        break;
                case CMODE_32:
                        i = (regno << 8) | regno;
                        p->pseudo_palette[regno] = (i << 16) | i;
                        break;
                }
        }

        return 0;
}


/********************  End of controlfb_ops implementation  ******************/



static void set_control_clock(unsigned char *params)
{
#ifdef CONFIG_ADB_CUDA
        struct adb_request req;
        int i;

        for (i = 0; i < 3; ++i) {
                cuda_request(&req, NULL, 5, CUDA_PACKET, CUDA_GET_SET_IIC,
                             0x50, i + 1, params[i]);
                while (!req.complete)
                        cuda_poll();
        }
#endif  
}


/*
 * finish off the driver initialization and register
 */
static int __init init_control(struct fb_info_control *p)
{
        int full, sense, vmode, cmode, vyres;
        struct fb_var_screeninfo var;
        int rc;
        
        printk(KERN_INFO "controlfb: ");

        full = p->total_vram == 0x400000;

        /* Try to pick a video mode out of NVRAM if we have one. */
#ifdef CONFIG_NVRAM
        if (default_cmode == CMODE_NVRAM) {
                cmode = nvram_read_byte(NV_CMODE);
                if(cmode < CMODE_8 || cmode > CMODE_32)
                        cmode = CMODE_8;
        } else
#endif
                cmode=default_cmode;
#ifdef CONFIG_NVRAM
        if (default_vmode == VMODE_NVRAM) {
                vmode = nvram_read_byte(NV_VMODE);
                if (vmode < 1 || vmode > VMODE_MAX ||
                    control_mac_modes[vmode - 1].m[full] < cmode) {
                        sense = read_control_sense(p);
                        printk("Monitor sense value = 0x%x, ", sense);
                        vmode = mac_map_monitor_sense(sense);
                        if (control_mac_modes[vmode - 1].m[full] < cmode)
                                vmode = VMODE_640_480_60;
                }
        } else
#endif
        {
                vmode=default_vmode;
                if (control_mac_modes[vmode - 1].m[full] < cmode) {
                        if (cmode > CMODE_8)
                                cmode--;
                        else
                                vmode = VMODE_640_480_60;
                }
        }

        /* Initialize info structure */
        control_init_info(&p->info, p);

        /* Setup default var */
        if (mac_vmode_to_var(vmode, cmode, &var) < 0) {
                /* This shouldn't happen! */
                printk("mac_vmode_to_var(%d, %d,) failed\n", vmode, cmode);
try_again:
                vmode = VMODE_640_480_60;
                cmode = CMODE_8;
                if (mac_vmode_to_var(vmode, cmode, &var) < 0) {
                        printk(KERN_ERR "controlfb: mac_vmode_to_var() failed\n");
                        return -ENXIO;
                }
                printk(KERN_INFO "controlfb: ");
        }
        printk("using video mode %d and color mode %d.\n", vmode, cmode);

        vyres = (p->total_vram - CTRLFB_OFF) / (var.xres << cmode);
        if (vyres > var.yres)
                var.yres_virtual = vyres;

        /* Apply default var */
        var.activate = FB_ACTIVATE_NOW;
        rc = fb_set_var(&p->info, &var);
        if (rc && (vmode != VMODE_640_480_60 || cmode != CMODE_8))
                goto try_again;

        /* Register with fbdev layer */
        if (register_framebuffer(&p->info) < 0)
                return -ENXIO;

        fb_info(&p->info, "control display adapter\n");

        return 0;
}

#define RADACAL_WRITE(a,d) \
        out_8(&p->cmap_regs->addr, (a)); \
        out_8(&p->cmap_regs->dat,   (d))

/* Now how about actually saying, Make it so! */
/* Some things in here probably don't need to be done each time. */
static void control_set_hardware(struct fb_info_control *p, struct fb_par_control *par)
{
        struct control_regvals  *r;
        volatile struct preg    __iomem *rp;
        int                     i, cmode;

        if (PAR_EQUAL(&p->par, par)) {
                /*
                 * check if only xoffset or yoffset differs.
                 * this prevents flickers in typical VT switch case.
                 */
                if (p->par.xoffset != par->xoffset ||
                    p->par.yoffset != par->yoffset)
                        set_screen_start(par->xoffset, par->yoffset, p);
                        
                return;
        }
        
        p->par = *par;
        cmode = p->par.cmode;
        r = &par->regvals;
        
        /* Turn off display */
        out_le32(CNTRL_REG(p,ctrl), 0x400 | par->ctrl);
        
        set_control_clock(r->clock_params);
        
        RADACAL_WRITE(0x20, r->radacal_ctrl);
        RADACAL_WRITE(0x21, p->control_use_bank2 ? 0 : 1);
        RADACAL_WRITE(0x10, 0);
        RADACAL_WRITE(0x11, 0);

        rp = &p->control_regs->vswin;
        for (i = 0; i < 16; ++i, ++rp)
                out_le32(&rp->r, r->regs[i]);
        
        out_le32(CNTRL_REG(p,pitch), par->pitch);
        out_le32(CNTRL_REG(p,mode), r->mode);
        out_le32(CNTRL_REG(p,vram_attr), p->vram_attr);
        out_le32(CNTRL_REG(p,start_addr), par->yoffset * par->pitch
                 + (par->xoffset << cmode));
        out_le32(CNTRL_REG(p,rfrcnt), 0x1e5);
        out_le32(CNTRL_REG(p,intr_ena), 0);

        /* Turn on display */
        out_le32(CNTRL_REG(p,ctrl), par->ctrl);

#ifdef CONFIG_BOOTX_TEXT
        btext_update_display(p->frame_buffer_phys + CTRLFB_OFF,
                             p->par.xres, p->par.yres,
                             (cmode == CMODE_32? 32: cmode == CMODE_16? 16: 8),
                             p->par.pitch);
#endif /* CONFIG_BOOTX_TEXT */
}


/*
 * Parse user specified options (`video=controlfb:')
 */
static void __init control_setup(char *options)
{
        char *this_opt;

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

        while ((this_opt = strsep(&options, ",")) != NULL) {
                if (!strncmp(this_opt, "vmode:", 6)) {
                        int vmode = simple_strtoul(this_opt+6, NULL, 0);
                        if (vmode > 0 && vmode <= VMODE_MAX &&
                            control_mac_modes[vmode - 1].m[1] >= 0)
                                default_vmode = vmode;
                } else if (!strncmp(this_opt, "cmode:", 6)) {
                        int depth = simple_strtoul(this_opt+6, NULL, 0);
                        switch (depth) {
                         case CMODE_8:
                         case CMODE_16:
                         case CMODE_32:
                                default_cmode = depth;
                                break;
                         case 8:
                                default_cmode = CMODE_8;
                                break;
                         case 15:
                         case 16:
                                default_cmode = CMODE_16;
                                break;
                         case 24:
                         case 32:
                                default_cmode = CMODE_32;
                                break;
                        }
                }
        }
}

static int __init control_init(void)
{
        struct device_node *dp;
        char *option = NULL;
        int ret = -ENXIO;

        if (fb_get_options("controlfb", &option))
                return -ENODEV;
        control_setup(option);

        dp = of_find_node_by_name(NULL, "control");
        if (dp != 0 && !control_of_init(dp))
                ret = 0;
        of_node_put(dp);

        return ret;
}

module_init(control_init);

/* Work out which banks of VRAM we have installed. */
/* danj: I guess the card just ignores writes to nonexistant VRAM... */

static void __init find_vram_size(struct fb_info_control *p)
{
        int bank1, bank2;

        /*
         * Set VRAM in 2MB (bank 1) mode
         * VRAM Bank 2 will be accessible through offset 0x600000 if present
         * and VRAM Bank 1 will not respond at that offset even if present
         */
        out_le32(CNTRL_REG(p,vram_attr), 0x31);

        out_8(&p->frame_buffer[0x600000], 0xb3);
        out_8(&p->frame_buffer[0x600001], 0x71);
        asm volatile("eieio; dcbf 0,%0" : : "r" (&p->frame_buffer[0x600000])
                                        : "memory" );
        mb();
        asm volatile("eieio; dcbi 0,%0" : : "r" (&p->frame_buffer[0x600000])
                                        : "memory" );
        mb();

        bank2 = (in_8(&p->frame_buffer[0x600000]) == 0xb3)
                && (in_8(&p->frame_buffer[0x600001]) == 0x71);

        /*
         * Set VRAM in 2MB (bank 2) mode
         * VRAM Bank 1 will be accessible through offset 0x000000 if present
         * and VRAM Bank 2 will not respond at that offset even if present
         */
        out_le32(CNTRL_REG(p,vram_attr), 0x39);

        out_8(&p->frame_buffer[0], 0x5a);
        out_8(&p->frame_buffer[1], 0xc7);
        asm volatile("eieio; dcbf 0,%0" : : "r" (&p->frame_buffer[0])
                                        : "memory" );
        mb();
        asm volatile("eieio; dcbi 0,%0" : : "r" (&p->frame_buffer[0])
                                        : "memory" );
        mb();

        bank1 = (in_8(&p->frame_buffer[0]) == 0x5a)
                && (in_8(&p->frame_buffer[1]) == 0xc7);

        if (bank2) {
                if (!bank1) {
                        /*
                         * vram bank 2 only
                         */
                        p->control_use_bank2 = 1;
                        p->vram_attr = 0x39;
                        p->frame_buffer += 0x600000;
                        p->frame_buffer_phys += 0x600000;
                } else {
                        /*
                         * 4 MB vram
                         */
                        p->vram_attr = 0x51;
                }
        } else {
                /*
                 * vram bank 1 only
                 */
                p->vram_attr = 0x31;
        }

        p->total_vram = (bank1 + bank2) * 0x200000;

        printk(KERN_INFO "controlfb: VRAM Total = %dMB "
                        "(%dMB @ bank 1, %dMB @ bank 2)\n",
                        (bank1 + bank2) << 1, bank1 << 1, bank2 << 1);
}


/*
 * find "control" and initialize
 */
static int __init control_of_init(struct device_node *dp)
{
        struct fb_info_control  *p;
        struct resource         fb_res, reg_res;

        if (control_fb) {
                printk(KERN_ERR "controlfb: only one control is supported\n");
                return -ENXIO;
        }

        if (of_pci_address_to_resource(dp, 2, &fb_res) ||
            of_pci_address_to_resource(dp, 1, &reg_res)) {
                printk(KERN_ERR "can't get 2 addresses for control\n");
                return -ENXIO;
        }
        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (p == 0)
                return -ENXIO;
        control_fb = p; /* save it for cleanups */

        /* Map in frame buffer and registers */
        p->fb_orig_base = fb_res.start;
        p->fb_orig_size = resource_size(&fb_res);
        /* use the big-endian aperture (??) */
        p->frame_buffer_phys = fb_res.start + 0x800000;
        p->control_regs_phys = reg_res.start;
        p->control_regs_size = resource_size(&reg_res);

        if (!p->fb_orig_base ||
            !request_mem_region(p->fb_orig_base,p->fb_orig_size,"controlfb")) {
                p->fb_orig_base = 0;
                goto error_out;
        }
        /* map at most 8MB for the frame buffer */
        p->frame_buffer = __ioremap(p->frame_buffer_phys, 0x800000,
                                    _PAGE_WRITETHRU);

        if (!p->control_regs_phys ||
            !request_mem_region(p->control_regs_phys, p->control_regs_size,
            "controlfb regs")) {
                p->control_regs_phys = 0;
                goto error_out;
        }
        p->control_regs = ioremap(p->control_regs_phys, p->control_regs_size);

        p->cmap_regs_phys = 0xf301b000;  /* XXX not in prom? */
        if (!request_mem_region(p->cmap_regs_phys, 0x1000, "controlfb cmap")) {
                p->cmap_regs_phys = 0;
                goto error_out;
        }
        p->cmap_regs = ioremap(p->cmap_regs_phys, 0x1000);

        if (!p->cmap_regs || !p->control_regs || !p->frame_buffer)
                goto error_out;

        find_vram_size(p);
        if (!p->total_vram)
                goto error_out;

        if (init_control(p) < 0)
                goto error_out;

        return 0;

error_out:
        control_cleanup();
        return -ENXIO;
}

/*
 * Get the monitor sense value.
 * Note that this can be called before calibrate_delay,
 * so we can't use udelay.
 */
static int read_control_sense(struct fb_info_control *p)
{
        int sense;

        out_le32(CNTRL_REG(p,mon_sense), 7);    /* drive all lines high */
        __delay(200);
        out_le32(CNTRL_REG(p,mon_sense), 077);  /* turn off drivers */
        __delay(2000);
        sense = (in_le32(CNTRL_REG(p,mon_sense)) & 0x1c0) << 2;

        /* drive each sense line low in turn and collect the other 2 */
        out_le32(CNTRL_REG(p,mon_sense), 033);  /* drive A low */
        __delay(2000);
        sense |= (in_le32(CNTRL_REG(p,mon_sense)) & 0xc0) >> 2;
        out_le32(CNTRL_REG(p,mon_sense), 055);  /* drive B low */
        __delay(2000);
        sense |= ((in_le32(CNTRL_REG(p,mon_sense)) & 0x100) >> 5)
                | ((in_le32(CNTRL_REG(p,mon_sense)) & 0x40) >> 4);
        out_le32(CNTRL_REG(p,mon_sense), 066);  /* drive C low */
        __delay(2000);
        sense |= (in_le32(CNTRL_REG(p,mon_sense)) & 0x180) >> 7;

        out_le32(CNTRL_REG(p,mon_sense), 077);  /* turn off drivers */
        
        return sense;
}

/**********************  Various translation functions  **********************/

#define CONTROL_PIXCLOCK_BASE   256016
#define CONTROL_PIXCLOCK_MIN    5000    /* ~ 200 MHz dot clock */

/*
 * calculate the clock paramaters to be sent to CUDA according to given
 * pixclock in pico second.
 */
static int calc_clock_params(unsigned long clk, unsigned char *param)
{
        unsigned long p0, p1, p2, k, l, m, n, min;

        if (clk > (CONTROL_PIXCLOCK_BASE << 3))
                return 1;

        p2 = ((clk << 4) < CONTROL_PIXCLOCK_BASE)? 3: 2;
        l = clk << p2;
        p0 = 0;
        p1 = 0;
        for (k = 1, min = l; k < 32; k++) {
                unsigned long rem;

                m = CONTROL_PIXCLOCK_BASE * k;
                n = m / l;
                rem = m % l;
                if (n && (n < 128) && rem < min) {
                        p0 = k;
                        p1 = n;
                        min = rem;
                }
        }
        if (!p0 || !p1)
                return 1;

        param[0] = p0;
        param[1] = p1;
        param[2] = p2;

        return 0;
}


/*
 * This routine takes a user-supplied var, and picks the best vmode/cmode
 * from it.
 */

static int control_var_to_par(struct fb_var_screeninfo *var,
        struct fb_par_control *par, const struct fb_info *fb_info)
{
        int cmode, piped_diff, hstep;
        unsigned hperiod, hssync, hsblank, hesync, heblank, piped, heq, hlfln,
                 hserr, vperiod, vssync, vesync, veblank, vsblank, vswin, vewin;
        unsigned long pixclock;
        struct fb_info_control *p =
                container_of(fb_info, struct fb_info_control, info);
        struct control_regvals *r = &par->regvals;

        switch (var->bits_per_pixel) {
        case 8:
                par->cmode = CMODE_8;
                if (p->total_vram > 0x200000) {
                        r->mode = 3;
                        r->radacal_ctrl = 0x20;
                        piped_diff = 13;
                } else {
                        r->mode = 2;
                        r->radacal_ctrl = 0x10;
                        piped_diff = 9;
                }
                break;
        case 15:
        case 16:
                par->cmode = CMODE_16;
                if (p->total_vram > 0x200000) {
                        r->mode = 2;
                        r->radacal_ctrl = 0x24;
                        piped_diff = 5;
                } else {
                        r->mode = 1;
                        r->radacal_ctrl = 0x14;
                        piped_diff = 3;
                }
                break;
        case 32:
                par->cmode = CMODE_32;
                if (p->total_vram > 0x200000) {
                        r->mode = 1;
                        r->radacal_ctrl = 0x28;
                } else {
                        r->mode = 0;
                        r->radacal_ctrl = 0x18;
                }
                piped_diff = 1;
                break;
        default:
                return -EINVAL;
        }

        /*
         * adjust xres and vxres so that the corresponding memory widths are
         * 32-byte aligned
         */
        hstep = 31 >> par->cmode;
        par->xres = (var->xres + hstep) & ~hstep;
        par->vxres = (var->xres_virtual + hstep) & ~hstep;
        par->xoffset = (var->xoffset + hstep) & ~hstep;
        if (par->vxres < par->xres)
                par->vxres = par->xres;
        par->pitch = par->vxres << par->cmode;

        par->yres = var->yres;
        par->vyres = var->yres_virtual;
        par->yoffset = var->yoffset;
        if (par->vyres < par->yres)
                par->vyres = par->yres;

        par->sync = var->sync;

        if (par->pitch * par->vyres + CTRLFB_OFF > p->total_vram)
                return -EINVAL;

        if (par->xoffset + par->xres > par->vxres)
                par->xoffset = par->vxres - par->xres;
        if (par->yoffset + par->yres > par->vyres)
                par->yoffset = par->vyres - par->yres;

        pixclock = (var->pixclock < CONTROL_PIXCLOCK_MIN)? CONTROL_PIXCLOCK_MIN:
                   var->pixclock;
        if (calc_clock_params(pixclock, r->clock_params))
                return -EINVAL;

        hperiod = ((var->left_margin + par->xres + var->right_margin
                    + var->hsync_len) >> 1) - 2;
        hssync = hperiod + 1;
        hsblank = hssync - (var->right_margin >> 1);
        hesync = (var->hsync_len >> 1) - 1;
        heblank = (var->left_margin >> 1) + hesync;
        piped = heblank - piped_diff;
        heq = var->hsync_len >> 2;
        hlfln = (hperiod+2) >> 1;
        hserr = hssync-hesync;
        vperiod = (var->vsync_len + var->lower_margin + par->yres
                   + var->upper_margin) << 1;
        vssync = vperiod - 2;
        vesync = (var->vsync_len << 1) - vperiod + vssync;
        veblank = (var->upper_margin << 1) + vesync;
        vsblank = vssync - (var->lower_margin << 1);
        vswin = (vsblank+vssync) >> 1;
        vewin = (vesync+veblank) >> 1;

        r->regs[0] = vswin;
        r->regs[1] = vsblank;
        r->regs[2] = veblank;
        r->regs[3] = vewin;
        r->regs[4] = vesync;
        r->regs[5] = vssync;
        r->regs[6] = vperiod;
        r->regs[7] = piped;
        r->regs[8] = hperiod;
        r->regs[9] = hsblank;
        r->regs[10] = heblank;
        r->regs[11] = hesync;
        r->regs[12] = hssync;
        r->regs[13] = heq;
        r->regs[14] = hlfln;
        r->regs[15] = hserr;

        if (par->xres >= 1280 && par->cmode >= CMODE_16)
                par->ctrl = 0x7f;
        else
                par->ctrl = 0x3b;

        if (mac_var_to_vmode(var, &par->vmode, &cmode))
                par->vmode = 0;

        return 0;
}


/*
 * Convert hardware data in par to an fb_var_screeninfo
 */

static void control_par_to_var(struct fb_par_control *par, struct fb_var_screeninfo *var)
{
        struct control_regints *rv;
        
        rv = (struct control_regints *) par->regvals.regs;
        
        memset(var, 0, sizeof(*var));
        var->xres = par->xres;
        var->yres = par->yres;
        var->xres_virtual = par->vxres;
        var->yres_virtual = par->vyres;
        var->xoffset = par->xoffset;
        var->yoffset = par->yoffset;
        
        switch(par->cmode) {
        default:
        case CMODE_8:
                var->bits_per_pixel = 8;
                var->red.length = 8;
                var->green.length = 8;
                var->blue.length = 8;
                break;
        case CMODE_16:  /* RGB 555 */
                var->bits_per_pixel = 16;
                var->red.offset = 10;
                var->red.length = 5;
                var->green.offset = 5;
                var->green.length = 5;
                var->blue.length = 5;
                break;
        case CMODE_32:  /* RGB 888 */

                var->bits_per_pixel = 32;
                var->red.offset = 16;
                var->red.length = 8;
                var->green.offset = 8;
                var->green.length = 8;
                var->blue.length = 8;
                var->transp.offset = 24;
                var->transp.length = 8;
                break;
        }
        var->height = -1;
        var->width = -1;
        var->vmode = FB_VMODE_NONINTERLACED;

        var->left_margin = (rv->heblank - rv->hesync) << 1;
        var->right_margin = (rv->hssync - rv->hsblank) << 1;
        var->hsync_len = (rv->hperiod + 2 - rv->hssync + rv->hesync) << 1;

        var->upper_margin = (rv->veblank - rv->vesync) >> 1;
        var->lower_margin = (rv->vssync - rv->vsblank) >> 1;
        var->vsync_len = (rv->vperiod - rv->vssync + rv->vesync) >> 1;

        var->sync = par->sync;

        /*
         * 10^12 * clock_params[0] / (3906400 * clock_params[1]
         *                            * 2^clock_params[2])
         * (10^12 * clock_params[0] / (3906400 * clock_params[1]))
         * >> clock_params[2]
         */
        /* (255990.17 * clock_params[0] / clock_params[1]) >> clock_params[2] */
        var->pixclock = CONTROL_PIXCLOCK_BASE * par->regvals.clock_params[0];
        var->pixclock /= par->regvals.clock_params[1];
        var->pixclock >>= par->regvals.clock_params[2];
}

/*
 * Set misc info vars for this driver
 */
static void __init control_init_info(struct fb_info *info, struct fb_info_control *p)
{
        /* Fill fb_info */
        info->par = &p->par;
        info->fbops = &controlfb_ops;
        info->pseudo_palette = p->pseudo_palette;
        info->flags = FBINFO_DEFAULT | FBINFO_HWACCEL_YPAN;
        info->screen_base = p->frame_buffer + CTRLFB_OFF;

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

        /* Fill fix common fields */
        strcpy(info->fix.id, "control");
        info->fix.mmio_start = p->control_regs_phys;
        info->fix.mmio_len = sizeof(struct control_regs);
        info->fix.type = FB_TYPE_PACKED_PIXELS;
        info->fix.smem_start = p->frame_buffer_phys + CTRLFB_OFF;
        info->fix.smem_len = p->total_vram - CTRLFB_OFF;
        info->fix.ywrapstep = 0;
        info->fix.type_aux = 0;
        info->fix.accel = FB_ACCEL_NONE;
}


static void control_cleanup(void)
{
        struct fb_info_control  *p = control_fb;

        if (!p)
                return;

        if (p->cmap_regs)
                iounmap(p->cmap_regs);
        if (p->control_regs)
                iounmap(p->control_regs);
        if (p->frame_buffer) {
                if (p->control_use_bank2)
                        p->frame_buffer -= 0x600000;
                iounmap(p->frame_buffer);
        }
        if (p->cmap_regs_phys)
                release_mem_region(p->cmap_regs_phys, 0x1000);
        if (p->control_regs_phys)
                release_mem_region(p->control_regs_phys, p->control_regs_size);
        if (p->fb_orig_base)
                release_mem_region(p->fb_orig_base, p->fb_orig_size);
        kfree(p);
}