/*
 * linux/drivers/video/fbmon.c
 *
 * Copyright (C) 2002 James Simmons <jsimmons@users.sf.net>
 *
 * Credits:
 *
 * The EDID Parser is a conglomeration from the following sources:
 *
 *   1. SciTech SNAP Graphics Architecture
 *      Copyright (C) 1991-2002 SciTech Software, Inc. All rights reserved.
 *
 *   2. XFree86 4.3.0, interpret_edid.c
 *      Copyright 1998 by Egbert Eich <Egbert.Eich@Physik.TU-Darmstadt.DE>
 *
 *   3. John Fremlin <vii@users.sourceforge.net> and
 *      Ani Joshi <ajoshi@unixbox.com>
 *
 * Generalized Timing Formula is derived from:
 *
 *      GTF Spreadsheet by Andy Morrish (1/5/97)
 *      available at http://www.vesa.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/fb.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <video/edid.h>
#include <video/of_videomode.h>
#include <video/videomode.h>
#include "../edid.h"

/*
 * EDID parser
 */

#undef DEBUG  /* define this for verbose EDID parsing output */

#ifdef DEBUG
#define DPRINTK(fmt, args...) printk(fmt,## args)
#else
#define DPRINTK(fmt, args...)
#endif

#define FBMON_FIX_HEADER  1
#define FBMON_FIX_INPUT   2
#define FBMON_FIX_TIMINGS 3

#ifdef CONFIG_FB_MODE_HELPERS
struct broken_edid {
        u8  manufacturer[4];
        u32 model;
        u32 fix;
};

static const struct broken_edid brokendb[] = {
        /* DEC FR-PCXAV-YZ */
        {
                .manufacturer = "DEC",
                .model        = 0x073a,
                .fix          = FBMON_FIX_HEADER,
        },
        /* ViewSonic PF775a */
        {
                .manufacturer = "VSC",
                .model        = 0x5a44,
                .fix          = FBMON_FIX_INPUT,
        },
        /* Sharp UXGA? */
        {
                .manufacturer = "SHP",
                .model        = 0x138e,
                .fix          = FBMON_FIX_TIMINGS,
        },
};

static const unsigned char edid_v1_header[] = { 0x00, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0x00
};

static void copy_string(unsigned char *c, unsigned char *s)
{
  int i;
  c = c + 5;
  for (i = 0; (i < 13 && *c != 0x0A); i++)
    *(s++) = *(c++);
  *s = 0;
  while (i-- && (*--s == 0x20)) *s = 0;
}

static int edid_is_serial_block(unsigned char *block)
{
        if ((block[0] == 0x00) && (block[1] == 0x00) &&
            (block[2] == 0x00) && (block[3] == 0xff) &&
            (block[4] == 0x00))
                return 1;
        else
                return 0;
}

static int edid_is_ascii_block(unsigned char *block)
{
        if ((block[0] == 0x00) && (block[1] == 0x00) &&
            (block[2] == 0x00) && (block[3] == 0xfe) &&
            (block[4] == 0x00))
                return 1;
        else
                return 0;
}

static int edid_is_limits_block(unsigned char *block)
{
        if ((block[0] == 0x00) && (block[1] == 0x00) &&
            (block[2] == 0x00) && (block[3] == 0xfd) &&
            (block[4] == 0x00))
                return 1;
        else
                return 0;
}

static int edid_is_monitor_block(unsigned char *block)
{
        if ((block[0] == 0x00) && (block[1] == 0x00) &&
            (block[2] == 0x00) && (block[3] == 0xfc) &&
            (block[4] == 0x00))
                return 1;
        else
                return 0;
}

static int edid_is_timing_block(unsigned char *block)
{
        if ((block[0] != 0x00) || (block[1] != 0x00) ||
            (block[2] != 0x00) || (block[4] != 0x00))
                return 1;
        else
                return 0;
}

static int check_edid(unsigned char *edid)
{
        unsigned char *block = edid + ID_MANUFACTURER_NAME, manufacturer[4];
        unsigned char *b;
        u32 model;
        int i, fix = 0, ret = 0;

        manufacturer[0] = ((block[0] & 0x7c) >> 2) + '@';
        manufacturer[1] = ((block[0] & 0x03) << 3) +
                ((block[1] & 0xe0) >> 5) + '@';
        manufacturer[2] = (block[1] & 0x1f) + '@';
        manufacturer[3] = 0;
        model = block[2] + (block[3] << 8);

        for (i = 0; i < ARRAY_SIZE(brokendb); i++) {
                if (!strncmp(manufacturer, brokendb[i].manufacturer, 4) &&
                        brokendb[i].model == model) {
                        fix = brokendb[i].fix;
                        break;
                }
        }

        switch (fix) {
        case FBMON_FIX_HEADER:
                for (i = 0; i < 8; i++) {
                        if (edid[i] != edid_v1_header[i]) {
                                ret = fix;
                                break;
                        }
                }
                break;
        case FBMON_FIX_INPUT:
                b = edid + EDID_STRUCT_DISPLAY;
                /* Only if display is GTF capable will
                   the input type be reset to analog */
                if (b[4] & 0x01 && b[0] & 0x80)
                        ret = fix;
                break;
        case FBMON_FIX_TIMINGS:
                b = edid + DETAILED_TIMING_DESCRIPTIONS_START;
                ret = fix;

                for (i = 0; i < 4; i++) {
                        if (edid_is_limits_block(b)) {
                                ret = 0;
                                break;
                        }

                        b += DETAILED_TIMING_DESCRIPTION_SIZE;
                }

                break;
        }

        if (ret)
                printk("fbmon: The EDID Block of "
                       "Manufacturer: %s Model: 0x%x is known to "
                       "be broken,\n",  manufacturer, model);

        return ret;
}

static void fix_edid(unsigned char *edid, int fix)
{
        int i;
        unsigned char *b, csum = 0;

        switch (fix) {
        case FBMON_FIX_HEADER:
                printk("fbmon: trying a header reconstruct\n");
                memcpy(edid, edid_v1_header, 8);
                break;
        case FBMON_FIX_INPUT:
                printk("fbmon: trying to fix input type\n");
                b = edid + EDID_STRUCT_DISPLAY;
                b[0] &= ~0x80;
                edid[127] += 0x80;
                break;
        case FBMON_FIX_TIMINGS:
                printk("fbmon: trying to fix monitor timings\n");
                b = edid + DETAILED_TIMING_DESCRIPTIONS_START;
                for (i = 0; i < 4; i++) {
                        if (!(edid_is_serial_block(b) ||
                              edid_is_ascii_block(b) ||
                              edid_is_monitor_block(b) ||
                              edid_is_timing_block(b))) {
                                b[0] = 0x00;
                                b[1] = 0x00;
                                b[2] = 0x00;
                                b[3] = 0xfd;
                                b[4] = 0x00;
                                b[5] = 60;   /* vfmin */
                                b[6] = 60;   /* vfmax */
                                b[7] = 30;   /* hfmin */
                                b[8] = 75;   /* hfmax */
                                b[9] = 17;   /* pixclock - 170 MHz*/
                                b[10] = 0;   /* GTF */
                                break;
                        }

                        b += DETAILED_TIMING_DESCRIPTION_SIZE;
                }

                for (i = 0; i < EDID_LENGTH - 1; i++)
                        csum += edid[i];

                edid[127] = 256 - csum;
                break;
        }
}

static int edid_checksum(unsigned char *edid)
{
        unsigned char csum = 0, all_null = 0;
        int i, err = 0, fix = check_edid(edid);

        if (fix)
                fix_edid(edid, fix);

        for (i = 0; i < EDID_LENGTH; i++) {
                csum += edid[i];
                all_null |= edid[i];
        }

        if (csum == 0x00 && all_null) {
                /* checksum passed, everything's good */
                err = 1;
        }

        return err;
}

static int edid_check_header(unsigned char *edid)
{
        int i, err = 1, fix = check_edid(edid);

        if (fix)
                fix_edid(edid, fix);

        for (i = 0; i < 8; i++) {
                if (edid[i] != edid_v1_header[i])
                        err = 0;
        }

        return err;
}

static void parse_vendor_block(unsigned char *block, struct fb_monspecs *specs)
{
        specs->manufacturer[0] = ((block[0] & 0x7c) >> 2) + '@';
        specs->manufacturer[1] = ((block[0] & 0x03) << 3) +
                ((block[1] & 0xe0) >> 5) + '@';
        specs->manufacturer[2] = (block[1] & 0x1f) + '@';
        specs->manufacturer[3] = 0;
        specs->model = block[2] + (block[3] << 8);
        specs->serial = block[4] + (block[5] << 8) +
               (block[6] << 16) + (block[7] << 24);
        specs->year = block[9] + 1990;
        specs->week = block[8];
        DPRINTK("   Manufacturer: %s\n", specs->manufacturer);
        DPRINTK("   Model: %x\n", specs->model);
        DPRINTK("   Serial#: %u\n", specs->serial);
        DPRINTK("   Year: %u Week %u\n", specs->year, specs->week);
}

static void get_dpms_capabilities(unsigned char flags,
                                  struct fb_monspecs *specs)
{
        specs->dpms = 0;
        if (flags & DPMS_ACTIVE_OFF)
                specs->dpms |= FB_DPMS_ACTIVE_OFF;
        if (flags & DPMS_SUSPEND)
                specs->dpms |= FB_DPMS_SUSPEND;
        if (flags & DPMS_STANDBY)
                specs->dpms |= FB_DPMS_STANDBY;
        DPRINTK("      DPMS: Active %s, Suspend %s, Standby %s\n",
               (flags & DPMS_ACTIVE_OFF) ? "yes" : "no",
               (flags & DPMS_SUSPEND)    ? "yes" : "no",
               (flags & DPMS_STANDBY)    ? "yes" : "no");
}

static void get_chroma(unsigned char *block, struct fb_monspecs *specs)
{
        int tmp;

        DPRINTK("      Chroma\n");
        /* Chromaticity data */
        tmp = ((block[5] & (3 << 6)) >> 6) | (block[0x7] << 2);
        tmp *= 1000;
        tmp += 512;
        specs->chroma.redx = tmp/1024;
        DPRINTK("         RedX:     0.%03d ", specs->chroma.redx);

        tmp = ((block[5] & (3 << 4)) >> 4) | (block[0x8] << 2);
        tmp *= 1000;
        tmp += 512;
        specs->chroma.redy = tmp/1024;
        DPRINTK("RedY:     0.%03d\n", specs->chroma.redy);

        tmp = ((block[5] & (3 << 2)) >> 2) | (block[0x9] << 2);
        tmp *= 1000;
        tmp += 512;
        specs->chroma.greenx = tmp/1024;
        DPRINTK("         GreenX:   0.%03d ", specs->chroma.greenx);

        tmp = (block[5] & 3) | (block[0xa] << 2);
        tmp *= 1000;
        tmp += 512;
        specs->chroma.greeny = tmp/1024;
        DPRINTK("GreenY:   0.%03d\n", specs->chroma.greeny);

        tmp = ((block[6] & (3 << 6)) >> 6) | (block[0xb] << 2);
        tmp *= 1000;
        tmp += 512;
        specs->chroma.bluex = tmp/1024;
        DPRINTK("         BlueX:    0.%03d ", specs->chroma.bluex);

        tmp = ((block[6] & (3 << 4)) >> 4) | (block[0xc] << 2);
        tmp *= 1000;
        tmp += 512;
        specs->chroma.bluey = tmp/1024;
        DPRINTK("BlueY:    0.%03d\n", specs->chroma.bluey);

        tmp = ((block[6] & (3 << 2)) >> 2) | (block[0xd] << 2);
        tmp *= 1000;
        tmp += 512;
        specs->chroma.whitex = tmp/1024;
        DPRINTK("         WhiteX:   0.%03d ", specs->chroma.whitex);

        tmp = (block[6] & 3) | (block[0xe] << 2);
        tmp *= 1000;
        tmp += 512;
        specs->chroma.whitey = tmp/1024;
        DPRINTK("WhiteY:   0.%03d\n", specs->chroma.whitey);
}

static void calc_mode_timings(int xres, int yres, int refresh,
                              struct fb_videomode *mode)
{
        struct fb_var_screeninfo *var;

        var = kzalloc(sizeof(struct fb_var_screeninfo), GFP_KERNEL);

        if (var) {
                var->xres = xres;
                var->yres = yres;
                fb_get_mode(FB_VSYNCTIMINGS | FB_IGNOREMON,
                            refresh, var, NULL);
                mode->xres = xres;
                mode->yres = yres;
                mode->pixclock = var->pixclock;
                mode->refresh = refresh;
                mode->left_margin = var->left_margin;
                mode->right_margin = var->right_margin;
                mode->upper_margin = var->upper_margin;
                mode->lower_margin = var->lower_margin;
                mode->hsync_len = var->hsync_len;
                mode->vsync_len = var->vsync_len;
                mode->vmode = 0;
                mode->sync = 0;
                kfree(var);
        }
}

static int get_est_timing(unsigned char *block, struct fb_videomode *mode)
{
        int num = 0;
        unsigned char c;

        c = block[0];
        if (c&0x80) {
                calc_mode_timings(720, 400, 70, &mode[num]);
                mode[num++].flag = FB_MODE_IS_CALCULATED;
                DPRINTK("      720x400@70Hz\n");
        }
        if (c&0x40) {
                calc_mode_timings(720, 400, 88, &mode[num]);
                mode[num++].flag = FB_MODE_IS_CALCULATED;
                DPRINTK("      720x400@88Hz\n");
        }
        if (c&0x20) {
                mode[num++] = vesa_modes[3];
                DPRINTK("      640x480@60Hz\n");
        }
        if (c&0x10) {
                calc_mode_timings(640, 480, 67, &mode[num]);
                mode[num++].flag = FB_MODE_IS_CALCULATED;
                DPRINTK("      640x480@67Hz\n");
        }
        if (c&0x08) {
                mode[num++] = vesa_modes[4];
                DPRINTK("      640x480@72Hz\n");
        }
        if (c&0x04) {
                mode[num++] = vesa_modes[5];
                DPRINTK("      640x480@75Hz\n");
        }
        if (c&0x02) {
                mode[num++] = vesa_modes[7];
                DPRINTK("      800x600@56Hz\n");
        }
        if (c&0x01) {
                mode[num++] = vesa_modes[8];
                DPRINTK("      800x600@60Hz\n");
        }

        c = block[1];
        if (c&0x80) {
                mode[num++] = vesa_modes[9];
                DPRINTK("      800x600@72Hz\n");
        }
        if (c&0x40) {
                mode[num++] = vesa_modes[10];
                DPRINTK("      800x600@75Hz\n");
        }
        if (c&0x20) {
                calc_mode_timings(832, 624, 75, &mode[num]);
                mode[num++].flag = FB_MODE_IS_CALCULATED;
                DPRINTK("      832x624@75Hz\n");
        }
        if (c&0x10) {
                mode[num++] = vesa_modes[12];
                DPRINTK("      1024x768@87Hz Interlaced\n");
        }
        if (c&0x08) {
                mode[num++] = vesa_modes[13];
                DPRINTK("      1024x768@60Hz\n");
        }
        if (c&0x04) {
                mode[num++] = vesa_modes[14];
                DPRINTK("      1024x768@70Hz\n");
        }
        if (c&0x02) {
                mode[num++] = vesa_modes[15];
                DPRINTK("      1024x768@75Hz\n");
        }
        if (c&0x01) {
                mode[num++] = vesa_modes[21];
                DPRINTK("      1280x1024@75Hz\n");
        }
        c = block[2];
        if (c&0x80) {
                mode[num++] = vesa_modes[17];
                DPRINTK("      1152x870@75Hz\n");
        }
        DPRINTK("      Manufacturer's mask: %x\n",c&0x7F);
        return num;
}

static int get_std_timing(unsigned char *block, struct fb_videomode *mode,
                          int ver, int rev, const struct fb_monspecs *specs)
{
        int i;

        for (i = 0; i < DMT_SIZE; i++) {
                u32 std_2byte_code = block[0] << 8 | block[1];
                if (std_2byte_code == dmt_modes[i].std_2byte_code)
                        break;
        }

        if (i < DMT_SIZE && dmt_modes[i].mode) {
                /* DMT mode found */
                *mode = *dmt_modes[i].mode;
                mode->flag |= FB_MODE_IS_STANDARD;
                DPRINTK("        DMT id=%d\n", dmt_modes[i].dmt_id);

        } else {
                int xres, yres = 0, refresh, ratio;

                xres = (block[0] + 31) * 8;
                if (xres <= 256)
                        return 0;

                ratio = (block[1] & 0xc0) >> 6;
                switch (ratio) {
                case 0:
                        /* in EDID 1.3 the meaning of 0 changed to 16:10 (prior 1:1) */
                        if (ver < 1 || (ver == 1 && rev < 3))
                                yres = xres;
                        else
                                yres = (xres * 10)/16;
                        break;
                case 1:
                        yres = (xres * 3)/4;
                        break;
                case 2:
                        yres = (xres * 4)/5;
                        break;
                case 3:
                        yres = (xres * 9)/16;
                        break;
                }
                refresh = (block[1] & 0x3f) + 60;
                DPRINTK("      %dx%d@%dHz\n", xres, yres, refresh);

                calc_mode_timings(xres, yres, refresh, mode);
        }

        /* Check the mode we got is within valid spec of the monitor */
        if (specs && specs->dclkmax
            && PICOS2KHZ(mode->pixclock) * 1000 > specs->dclkmax) {
                DPRINTK("        mode exceed max DCLK\n");
                return 0;
        }

        return 1;
}

static int get_dst_timing(unsigned char *block, struct fb_videomode *mode,
                          int ver, int rev, const struct fb_monspecs *specs)
{
        int j, num = 0;

        for (j = 0; j < 6; j++, block += STD_TIMING_DESCRIPTION_SIZE)
                num += get_std_timing(block, &mode[num], ver, rev, specs);

        return num;
}

static void get_detailed_timing(unsigned char *block,
                                struct fb_videomode *mode)
{
        mode->xres = H_ACTIVE;
        mode->yres = V_ACTIVE;
        mode->pixclock = PIXEL_CLOCK;
        mode->pixclock /= 1000;
        mode->pixclock = KHZ2PICOS(mode->pixclock);
        mode->right_margin = H_SYNC_OFFSET;
        mode->left_margin = (H_ACTIVE + H_BLANKING) -
                (H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH);
        mode->upper_margin = V_BLANKING - V_SYNC_OFFSET -
                V_SYNC_WIDTH;
        mode->lower_margin = V_SYNC_OFFSET;
        mode->hsync_len = H_SYNC_WIDTH;
        mode->vsync_len = V_SYNC_WIDTH;
        if (HSYNC_POSITIVE)
                mode->sync |= FB_SYNC_HOR_HIGH_ACT;
        if (VSYNC_POSITIVE)
                mode->sync |= FB_SYNC_VERT_HIGH_ACT;
        mode->refresh = PIXEL_CLOCK/((H_ACTIVE + H_BLANKING) *
                                     (V_ACTIVE + V_BLANKING));
        if (INTERLACED) {
                mode->yres *= 2;
                mode->upper_margin *= 2;
                mode->lower_margin *= 2;
                mode->vsync_len *= 2;
                mode->vmode |= FB_VMODE_INTERLACED;
        }
        mode->flag = FB_MODE_IS_DETAILED;

        DPRINTK("      %d MHz ",  PIXEL_CLOCK/1000000);
        DPRINTK("%d %d %d %d ", H_ACTIVE, H_ACTIVE + H_SYNC_OFFSET,
               H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH, H_ACTIVE + H_BLANKING);
        DPRINTK("%d %d %d %d ", V_ACTIVE, V_ACTIVE + V_SYNC_OFFSET,
               V_ACTIVE + V_SYNC_OFFSET + V_SYNC_WIDTH, V_ACTIVE + V_BLANKING);
        DPRINTK("%sHSync %sVSync\n\n", (HSYNC_POSITIVE) ? "+" : "-",
               (VSYNC_POSITIVE) ? "+" : "-");
}

/**
 * fb_create_modedb - create video mode database
 * @edid: EDID data
 * @dbsize: database size
 *
 * RETURNS: struct fb_videomode, @dbsize contains length of database
 *
 * DESCRIPTION:
 * This function builds a mode database using the contents of the EDID
 * data
 */
static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize,
                                             const struct fb_monspecs *specs)
{
        struct fb_videomode *mode, *m;
        unsigned char *block;
        int num = 0, i, first = 1;
        int ver, rev;

        mode = kcalloc(50, sizeof(struct fb_videomode), GFP_KERNEL);
        if (mode == NULL)
                return NULL;

        if (edid == NULL || !edid_checksum(edid) ||
            !edid_check_header(edid)) {
                kfree(mode);
                return NULL;
        }

        ver = edid[EDID_STRUCT_VERSION];
        rev = edid[EDID_STRUCT_REVISION];

        *dbsize = 0;

        DPRINTK("   Detailed Timings\n");
        block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
        for (i = 0; i < 4; i++, block+= DETAILED_TIMING_DESCRIPTION_SIZE) {
                if (!(block[0] == 0x00 && block[1] == 0x00)) {
                        get_detailed_timing(block, &mode[num]);
                        if (first) {
                                mode[num].flag |= FB_MODE_IS_FIRST;
                                first = 0;
                        }
                        num++;
                }
        }

        DPRINTK("   Supported VESA Modes\n");
        block = edid + ESTABLISHED_TIMING_1;
        num += get_est_timing(block, &mode[num]);

        DPRINTK("   Standard Timings\n");
        block = edid + STD_TIMING_DESCRIPTIONS_START;
        for (i = 0; i < STD_TIMING; i++, block += STD_TIMING_DESCRIPTION_SIZE)
                num += get_std_timing(block, &mode[num], ver, rev, specs);

        block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
        for (i = 0; i < 4; i++, block+= DETAILED_TIMING_DESCRIPTION_SIZE) {
                if (block[0] == 0x00 && block[1] == 0x00 && block[3] == 0xfa)
                        num += get_dst_timing(block + 5, &mode[num],
                                              ver, rev, specs);
        }

        /* Yikes, EDID data is totally useless */
        if (!num) {
                kfree(mode);
                return NULL;
        }

        *dbsize = num;
        m = kmalloc_array(num, sizeof(struct fb_videomode), GFP_KERNEL);
        if (!m)
                return mode;
        memmove(m, mode, num * sizeof(struct fb_videomode));
        kfree(mode);
        return m;
}

/**
 * fb_destroy_modedb - destroys mode database
 * @modedb: mode database to destroy
 *
 * DESCRIPTION:
 * Destroy mode database created by fb_create_modedb
 */
void fb_destroy_modedb(struct fb_videomode *modedb)
{
        kfree(modedb);
}

static int fb_get_monitor_limits(unsigned char *edid, struct fb_monspecs *specs)
{
        int i, retval = 1;
        unsigned char *block;

        block = edid + DETAILED_TIMING_DESCRIPTIONS_START;

        DPRINTK("      Monitor Operating Limits: ");

        for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
                if (edid_is_limits_block(block)) {
                        specs->hfmin = H_MIN_RATE * 1000;
                        specs->hfmax = H_MAX_RATE * 1000;
                        specs->vfmin = V_MIN_RATE;
                        specs->vfmax = V_MAX_RATE;
                        specs->dclkmax = MAX_PIXEL_CLOCK * 1000000;
                        specs->gtf = (GTF_SUPPORT) ? 1 : 0;
                        retval = 0;
                        DPRINTK("From EDID\n");
                        break;
                }
        }

        /* estimate monitor limits based on modes supported */
        if (retval) {
                struct fb_videomode *modes, *mode;
                int num_modes, hz, hscan, pixclock;
                int vtotal, htotal;

                modes = fb_create_modedb(edid, &num_modes, specs);
                if (!modes) {
                        DPRINTK("None Available\n");
                        return 1;
                }

                retval = 0;
                for (i = 0; i < num_modes; i++) {
                        mode = &modes[i];
                        pixclock = PICOS2KHZ(modes[i].pixclock) * 1000;
                        htotal = mode->xres + mode->right_margin + mode->hsync_len
                                + mode->left_margin;
                        vtotal = mode->yres + mode->lower_margin + mode->vsync_len
                                + mode->upper_margin;

                        if (mode->vmode & FB_VMODE_INTERLACED)
                                vtotal /= 2;

                        if (mode->vmode & FB_VMODE_DOUBLE)
                                vtotal *= 2;

                        hscan = (pixclock + htotal / 2) / htotal;
                        hscan = (hscan + 500) / 1000 * 1000;
                        hz = (hscan + vtotal / 2) / vtotal;

                        if (specs->dclkmax == 0 || specs->dclkmax < pixclock)
                                specs->dclkmax = pixclock;

                        if (specs->dclkmin == 0 || specs->dclkmin > pixclock)
                                specs->dclkmin = pixclock;

                        if (specs->hfmax == 0 || specs->hfmax < hscan)
                                specs->hfmax = hscan;

                        if (specs->hfmin == 0 || specs->hfmin > hscan)
                                specs->hfmin = hscan;

                        if (specs->vfmax == 0 || specs->vfmax < hz)
                                specs->vfmax = hz;

                        if (specs->vfmin == 0 || specs->vfmin > hz)
                                specs->vfmin = hz;
                }
                DPRINTK("Extrapolated\n");
                fb_destroy_modedb(modes);
        }
        DPRINTK("           H: %d-%dKHz V: %d-%dHz DCLK: %dMHz\n",
                specs->hfmin/1000, specs->hfmax/1000, specs->vfmin,
                specs->vfmax, specs->dclkmax/1000000);
        return retval;
}

static void get_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
        unsigned char c, *block;

        block = edid + EDID_STRUCT_DISPLAY;

        fb_get_monitor_limits(edid, specs);

        c = block[0] & 0x80;
        specs->input = 0;
        if (c) {
                specs->input |= FB_DISP_DDI;
                DPRINTK("      Digital Display Input");
        } else {
                DPRINTK("      Analog Display Input: Input Voltage - ");
                switch ((block[0] & 0x60) >> 5) {
                case 0:
                        DPRINTK("0.700V/0.300V");
                        specs->input |= FB_DISP_ANA_700_300;
                        break;
                case 1:
                        DPRINTK("0.714V/0.286V");
                        specs->input |= FB_DISP_ANA_714_286;
                        break;
                case 2:
                        DPRINTK("1.000V/0.400V");
                        specs->input |= FB_DISP_ANA_1000_400;
                        break;
                case 3:
                        DPRINTK("0.700V/0.000V");
                        specs->input |= FB_DISP_ANA_700_000;
                        break;
                }
        }
        DPRINTK("\n      Sync: ");
        c = block[0] & 0x10;
        if (c)
                DPRINTK("      Configurable signal level\n");
        c = block[0] & 0x0f;
        specs->signal = 0;
        if (c & 0x10) {
                DPRINTK("Blank to Blank ");
                specs->signal |= FB_SIGNAL_BLANK_BLANK;
        }
        if (c & 0x08) {
                DPRINTK("Separate ");
                specs->signal |= FB_SIGNAL_SEPARATE;
        }
        if (c & 0x04) {
                DPRINTK("Composite ");
                specs->signal |= FB_SIGNAL_COMPOSITE;
        }
        if (c & 0x02) {
                DPRINTK("Sync on Green ");
                specs->signal |= FB_SIGNAL_SYNC_ON_GREEN;
        }
        if (c & 0x01) {
                DPRINTK("Serration on ");
                specs->signal |= FB_SIGNAL_SERRATION_ON;
        }
        DPRINTK("\n");
        specs->max_x = block[1];
        specs->max_y = block[2];
        DPRINTK("      Max H-size in cm: ");
        if (specs->max_x)
                DPRINTK("%d\n", specs->max_x);
        else
                DPRINTK("variable\n");
        DPRINTK("      Max V-size in cm: ");
        if (specs->max_y)
                DPRINTK("%d\n", specs->max_y);
        else
                DPRINTK("variable\n");

        c = block[3];
        specs->gamma = c+100;
        DPRINTK("      Gamma: ");
        DPRINTK("%d.%d\n", specs->gamma/100, specs->gamma % 100);

        get_dpms_capabilities(block[4], specs);

        switch ((block[4] & 0x18) >> 3) {
        case 0:
                DPRINTK("      Monochrome/Grayscale\n");
                specs->input |= FB_DISP_MONO;
                break;
        case 1:
                DPRINTK("      RGB Color Display\n");
                specs->input |= FB_DISP_RGB;
                break;
        case 2:
                DPRINTK("      Non-RGB Multicolor Display\n");
                specs->input |= FB_DISP_MULTI;
                break;
        default:
                DPRINTK("      Unknown\n");
                specs->input |= FB_DISP_UNKNOWN;
                break;
        }

        get_chroma(block, specs);

        specs->misc = 0;
        c = block[4] & 0x7;
        if (c & 0x04) {
                DPRINTK("      Default color format is primary\n");
                specs->misc |= FB_MISC_PRIM_COLOR;
        }
        if (c & 0x02) {
                DPRINTK("      First DETAILED Timing is preferred\n");
                specs->misc |= FB_MISC_1ST_DETAIL;
        }
        if (c & 0x01) {
                printk("      Display is GTF capable\n");
                specs->gtf = 1;
        }
}

int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var)
{
        int i;
        unsigned char *block;

        if (edid == NULL || var == NULL)
                return 1;

        if (!(edid_checksum(edid)))
                return 1;

        if (!(edid_check_header(edid)))
                return 1;

        block = edid + DETAILED_TIMING_DESCRIPTIONS_START;

        for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
                if (edid_is_timing_block(block)) {
                        var->xres = var->xres_virtual = H_ACTIVE;
                        var->yres = var->yres_virtual = V_ACTIVE;
                        var->height = var->width = 0;
                        var->right_margin = H_SYNC_OFFSET;
                        var->left_margin = (H_ACTIVE + H_BLANKING) -
                                (H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH);
                        var->upper_margin = V_BLANKING - V_SYNC_OFFSET -
                                V_SYNC_WIDTH;
                        var->lower_margin = V_SYNC_OFFSET;
                        var->hsync_len = H_SYNC_WIDTH;
                        var->vsync_len = V_SYNC_WIDTH;
                        var->pixclock = PIXEL_CLOCK;
                        var->pixclock /= 1000;
                        var->pixclock = KHZ2PICOS(var->pixclock);

                        if (HSYNC_POSITIVE)
                                var->sync |= FB_SYNC_HOR_HIGH_ACT;
                        if (VSYNC_POSITIVE)
                                var->sync |= FB_SYNC_VERT_HIGH_ACT;
                        return 0;
                }
        }
        return 1;
}

void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
        unsigned char *block;
        int i, found = 0;

        if (edid == NULL)
                return;

        if (!(edid_checksum(edid)))
                return;

        if (!(edid_check_header(edid)))
                return;

        memset(specs, 0, sizeof(struct fb_monspecs));

        specs->version = edid[EDID_STRUCT_VERSION];
        specs->revision = edid[EDID_STRUCT_REVISION];

        DPRINTK("========================================\n");
        DPRINTK("Display Information (EDID)\n");
        DPRINTK("========================================\n");
        DPRINTK("   EDID Version %d.%d\n", (int) specs->version,
               (int) specs->revision);

        parse_vendor_block(edid + ID_MANUFACTURER_NAME, specs);

        block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
        for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
                if (edid_is_serial_block(block)) {
                        copy_string(block, specs->serial_no);
                        DPRINTK("   Serial Number: %s\n", specs->serial_no);
                } else if (edid_is_ascii_block(block)) {
                        copy_string(block, specs->ascii);
                        DPRINTK("   ASCII Block: %s\n", specs->ascii);
                } else if (edid_is_monitor_block(block)) {
                        copy_string(block, specs->monitor);
                        DPRINTK("   Monitor Name: %s\n", specs->monitor);
                }
        }

        DPRINTK("   Display Characteristics:\n");
        get_monspecs(edid, specs);

        specs->modedb = fb_create_modedb(edid, &specs->modedb_len, specs);
        if (!specs->modedb)
                return;

        /*
         * Workaround for buggy EDIDs that sets that the first
         * detailed timing is preferred but has not detailed
         * timing specified
         */
        for (i = 0; i < specs->modedb_len; i++) {
                if (specs->modedb[i].flag & FB_MODE_IS_DETAILED) {
                        found = 1;
                        break;
                }
        }

        if (!found)
                specs->misc &= ~FB_MISC_1ST_DETAIL;

        DPRINTK("========================================\n");
}

/**
 * fb_edid_add_monspecs() - add monitor video modes from E-EDID data
 * @edid:       128 byte array with an E-EDID block
 * @spacs:      monitor specs to be extended
 */
void fb_edid_add_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
        unsigned char *block;
        struct fb_videomode *m;
        int num = 0, i;
        u8 svd[64], edt[(128 - 4) / DETAILED_TIMING_DESCRIPTION_SIZE];
        u8 pos = 4, svd_n = 0;

        if (!edid)
                return;

        if (!edid_checksum(edid))
                return;

        if (edid[0] != 0x2 ||
            edid[2] < 4 || edid[2] > 128 - DETAILED_TIMING_DESCRIPTION_SIZE)
                return;

        DPRINTK("  Short Video Descriptors\n");

        while (pos < edid[2]) {
                u8 len = edid[pos] & 0x1f, type = (edid[pos] >> 5) & 7;
                pr_debug("Data block %u of %u bytes\n", type, len);
                if (type == 2) {
                        for (i = pos; i < pos + len; i++) {
                                u8 idx = edid[pos + i] & 0x7f;
                                svd[svd_n++] = idx;
                                pr_debug("N%sative mode #%d\n",
                                         edid[pos + i] & 0x80 ? "" : "on-n", idx);
                        }
                } else if (type == 3 && len >= 3) {
                        /* Check Vendor Specific Data Block.  For HDMI,
                           it is always 00-0C-03 for HDMI Licensing, LLC. */
                        if (edid[pos + 1] == 3 && edid[pos + 2] == 0xc &&
                            edid[pos + 3] == 0)
                                specs->misc |= FB_MISC_HDMI;
                }
                pos += len + 1;
        }

        block = edid + edid[2];

        DPRINTK("  Extended Detailed Timings\n");

        for (i = 0; i < (128 - edid[2]) / DETAILED_TIMING_DESCRIPTION_SIZE;
             i++, block += DETAILED_TIMING_DESCRIPTION_SIZE)
                if (PIXEL_CLOCK != 0)
                        edt[num++] = block - edid;

        /* Yikes, EDID data is totally useless */
        if (!(num + svd_n))
                return;

        m = kcalloc(specs->modedb_len + num + svd_n,
                    sizeof(struct fb_videomode),
                    GFP_KERNEL);

        if (!m)
                return;

        memcpy(m, specs->modedb, specs->modedb_len * sizeof(struct fb_videomode));

        for (i = specs->modedb_len; i < specs->modedb_len + num; i++) {
                get_detailed_timing(edid + edt[i - specs->modedb_len], &m[i]);
                if (i == specs->modedb_len)
                        m[i].flag |= FB_MODE_IS_FIRST;
                pr_debug("Adding %ux%u@%u\n", m[i].xres, m[i].yres, m[i].refresh);
        }

        for (i = specs->modedb_len + num; i < specs->modedb_len + num + svd_n; i++) {
                int idx = svd[i - specs->modedb_len - num];
                if (!idx || idx >= ARRAY_SIZE(cea_modes)) {
                        pr_warn("Reserved SVD code %d\n", idx);
                } else if (!cea_modes[idx].xres) {
                        pr_warn("Unimplemented SVD code %d\n", idx);
                } else {
                        memcpy(&m[i], cea_modes + idx, sizeof(m[i]));
                        pr_debug("Adding SVD #%d: %ux%u@%u\n", idx,
                                 m[i].xres, m[i].yres, m[i].refresh);
                }
        }

        kfree(specs->modedb);
        specs->modedb = m;
        specs->modedb_len = specs->modedb_len + num + svd_n;
}

/*
 * VESA Generalized Timing Formula (GTF)
 */

#define FLYBACK                     550
#define V_FRONTPORCH                1
#define H_OFFSET                    40
#define H_SCALEFACTOR               20
#define H_BLANKSCALE                128
#define H_GRADIENT                  600
#define C_VAL                       30
#define M_VAL                       300

struct __fb_timings {
        u32 dclk;
        u32 hfreq;
        u32 vfreq;
        u32 hactive;
        u32 vactive;
        u32 hblank;
        u32 vblank;
        u32 htotal;
        u32 vtotal;
};

/**
 * fb_get_vblank - get vertical blank time
 * @hfreq: horizontal freq
 *
 * DESCRIPTION:
 * vblank = right_margin + vsync_len + left_margin
 *
 *    given: right_margin = 1 (V_FRONTPORCH)
 *           vsync_len    = 3
 *           flyback      = 550
 *
 *                          flyback * hfreq
 *           left_margin  = --------------- - vsync_len
 *                           1000000
 */
static u32 fb_get_vblank(u32 hfreq)
{
        u32 vblank;

        vblank = (hfreq * FLYBACK)/1000;
        vblank = (vblank + 500)/1000;
        return (vblank + V_FRONTPORCH);
}

/**
 * fb_get_hblank_by_freq - get horizontal blank time given hfreq
 * @hfreq: horizontal freq
 * @xres: horizontal resolution in pixels
 *
 * DESCRIPTION:
 *
 *           xres * duty_cycle
 * hblank = ------------------
 *           100 - duty_cycle
 *
 * duty cycle = percent of htotal assigned to inactive display
 * duty cycle = C - (M/Hfreq)
 *
 * where: C = ((offset - scale factor) * blank_scale)
 *            -------------------------------------- + scale factor
 *                        256
 *        M = blank_scale * gradient
 *
 */
static u32 fb_get_hblank_by_hfreq(u32 hfreq, u32 xres)
{
        u32 c_val, m_val, duty_cycle, hblank;

        c_val = (((H_OFFSET - H_SCALEFACTOR) * H_BLANKSCALE)/256 +
                 H_SCALEFACTOR) * 1000;
        m_val = (H_BLANKSCALE * H_GRADIENT)/256;
        m_val = (m_val * 1000000)/hfreq;
        duty_cycle = c_val - m_val;
        hblank = (xres * duty_cycle)/(100000 - duty_cycle);
        return (hblank);
}

/**
 * fb_get_hblank_by_dclk - get horizontal blank time given pixelclock
 * @dclk: pixelclock in Hz
 * @xres: horizontal resolution in pixels
 *
 * DESCRIPTION:
 *
 *           xres * duty_cycle
 * hblank = ------------------
 *           100 - duty_cycle
 *
 * duty cycle = percent of htotal assigned to inactive display
 * duty cycle = C - (M * h_period)
 *
 * where: h_period = SQRT(100 - C + (0.4 * xres * M)/dclk) + C - 100
 *                   -----------------------------------------------
 *                                    2 * M
 *        M = 300;
 *        C = 30;

 */
static u32 fb_get_hblank_by_dclk(u32 dclk, u32 xres)
{
        u32 duty_cycle, h_period, hblank;

        dclk /= 1000;
        h_period = 100 - C_VAL;
        h_period *= h_period;
        h_period += (M_VAL * xres * 2 * 1000)/(5 * dclk);
        h_period *= 10000;

        h_period = int_sqrt(h_period);
        h_period -= (100 - C_VAL) * 100;
        h_period *= 1000;
        h_period /= 2 * M_VAL;

        duty_cycle = C_VAL * 1000 - (M_VAL * h_period)/100;
        hblank = (xres * duty_cycle)/(100000 - duty_cycle) + 8;
        hblank &= ~15;
        return (hblank);
}

/**
 * fb_get_hfreq - estimate hsync
 * @vfreq: vertical refresh rate
 * @yres: vertical resolution
 *
 * DESCRIPTION:
 *
 *          (yres + front_port) * vfreq * 1000000
 * hfreq = -------------------------------------
 *          (1000000 - (vfreq * FLYBACK)
 *
 */

static u32 fb_get_hfreq(u32 vfreq, u32 yres)
{
        u32 divisor, hfreq;

        divisor = (1000000 - (vfreq * FLYBACK))/1000;
        hfreq = (yres + V_FRONTPORCH) * vfreq  * 1000;
        return (hfreq/divisor);
}

static void fb_timings_vfreq(struct __fb_timings *timings)
{
        timings->hfreq = fb_get_hfreq(timings->vfreq, timings->vactive);
        timings->vblank = fb_get_vblank(timings->hfreq);
        timings->vtotal = timings->vactive + timings->vblank;
        timings->hblank = fb_get_hblank_by_hfreq(timings->hfreq,
                                                 timings->hactive);
        timings->htotal = timings->hactive + timings->hblank;
        timings->dclk = timings->htotal * timings->hfreq;
}

static void fb_timings_hfreq(struct __fb_timings *timings)
{
        timings->vblank = fb_get_vblank(timings->hfreq);
        timings->vtotal = timings->vactive + timings->vblank;
        timings->vfreq = timings->hfreq/timings->vtotal;
        timings->hblank = fb_get_hblank_by_hfreq(timings->hfreq,
                                                 timings->hactive);
        timings->htotal = timings->hactive + timings->hblank;
        timings->dclk = timings->htotal * timings->hfreq;
}

static void fb_timings_dclk(struct __fb_timings *timings)
{
        timings->hblank = fb_get_hblank_by_dclk(timings->dclk,
                                                timings->hactive);
        timings->htotal = timings->hactive + timings->hblank;
        timings->hfreq = timings->dclk/timings->htotal;
        timings->vblank = fb_get_vblank(timings->hfreq);
        timings->vtotal = timings->vactive + timings->vblank;
        timings->vfreq = timings->hfreq/timings->vtotal;
}

/*
 * fb_get_mode - calculates video mode using VESA GTF
 * @flags: if: 0 - maximize vertical refresh rate
 *             1 - vrefresh-driven calculation;
 *             2 - hscan-driven calculation;
 *             3 - pixelclock-driven calculation;
 * @val: depending on @flags, ignored, vrefresh, hsync or pixelclock
 * @var: pointer to fb_var_screeninfo
 * @info: pointer to fb_info
 *
 * DESCRIPTION:
 * Calculates video mode based on monitor specs using VESA GTF.
 * The GTF is best for VESA GTF compliant monitors but is
 * specifically formulated to work for older monitors as well.
 *
 * If @flag==0, the function will attempt to maximize the
 * refresh rate.  Otherwise, it will calculate timings based on
 * the flag and accompanying value.
 *
 * If FB_IGNOREMON bit is set in @flags, monitor specs will be
 * ignored and @var will be filled with the calculated timings.
 *
 * All calculations are based on the VESA GTF Spreadsheet
 * available at VESA's public ftp (http://www.vesa.org).
 *
 * NOTES:
 * The timings generated by the GTF will be different from VESA
 * DMT.  It might be a good idea to keep a table of standard
 * VESA modes as well.  The GTF may also not work for some displays,
 * such as, and especially, analog TV.
 *
 * REQUIRES:
 * A valid info->monspecs, otherwise 'safe numbers' will be used.
 */
int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var, struct fb_info *info)
{
        struct __fb_timings *timings;
        u32 interlace = 1, dscan = 1;
        u32 hfmin, hfmax, vfmin, vfmax, dclkmin, dclkmax, err = 0;


        timings = kzalloc(sizeof(struct __fb_timings), GFP_KERNEL);

        if (!timings)
                return -ENOMEM;

        /*
         * If monspecs are invalid, use values that are enough
         * for 640x480@60
         */
        if (!info || !info->monspecs.hfmax || !info->monspecs.vfmax ||
            !info->monspecs.dclkmax ||
            info->monspecs.hfmax < info->monspecs.hfmin ||
            info->monspecs.vfmax < info->monspecs.vfmin ||
            info->monspecs.dclkmax < info->monspecs.dclkmin) {
                hfmin = 29000; hfmax = 30000;
                vfmin = 60; vfmax = 60;
                dclkmin = 0; dclkmax = 25000000;
        } else {
                hfmin = info->monspecs.hfmin;
                hfmax = info->monspecs.hfmax;
                vfmin = info->monspecs.vfmin;
                vfmax = info->monspecs.vfmax;
                dclkmin = info->monspecs.dclkmin;
                dclkmax = info->monspecs.dclkmax;
        }

        timings->hactive = var->xres;
        timings->vactive = var->yres;
        if (var->vmode & FB_VMODE_INTERLACED) {
                timings->vactive /= 2;
                interlace = 2;
        }
        if (var->vmode & FB_VMODE_DOUBLE) {
                timings->vactive *= 2;
                dscan = 2;
        }

        switch (flags & ~FB_IGNOREMON) {
        case FB_MAXTIMINGS: /* maximize refresh rate */
                timings->hfreq = hfmax;
                fb_timings_hfreq(timings);
                if (timings->vfreq > vfmax) {
                        timings->vfreq = vfmax;
                        fb_timings_vfreq(timings);
                }
                if (timings->dclk > dclkmax) {
                        timings->dclk = dclkmax;
                        fb_timings_dclk(timings);
                }
                break;
        case FB_VSYNCTIMINGS: /* vrefresh driven */
                timings->vfreq = val;
                fb_timings_vfreq(timings);
                break;
        case FB_HSYNCTIMINGS: /* hsync driven */
                timings->hfreq = val;
                fb_timings_hfreq(timings);
                break;
        case FB_DCLKTIMINGS: /* pixelclock driven */
                timings->dclk = PICOS2KHZ(val) * 1000;
                fb_timings_dclk(timings);
                break;
        default:
                err = -EINVAL;

        }

        if (err || (!(flags & FB_IGNOREMON) &&
            (timings->vfreq < vfmin || timings->vfreq > vfmax ||
             timings->hfreq < hfmin || timings->hfreq > hfmax ||
             timings->dclk < dclkmin || timings->dclk > dclkmax))) {
                err = -EINVAL;
        } else {
                var->pixclock = KHZ2PICOS(timings->dclk/1000);
                var->hsync_len = (timings->htotal * 8)/100;
                var->right_margin = (timings->hblank/2) - var->hsync_len;
                var->left_margin = timings->hblank - var->right_margin -
                        var->hsync_len;
                var->vsync_len = (3 * interlace)/dscan;
                var->lower_margin = (1 * interlace)/dscan;
                var->upper_margin = (timings->vblank * interlace)/dscan -
                        (var->vsync_len + var->lower_margin);
        }

        kfree(timings);
        return err;
}

#ifdef CONFIG_VIDEOMODE_HELPERS
int fb_videomode_from_videomode(const struct videomode *vm,
                                struct fb_videomode *fbmode)
{
        unsigned int htotal, vtotal;

        fbmode->xres = vm->hactive;
        fbmode->left_margin = vm->hback_porch;
        fbmode->right_margin = vm->hfront_porch;
        fbmode->hsync_len = vm->hsync_len;

        fbmode->yres = vm->vactive;
        fbmode->upper_margin = vm->vback_porch;
        fbmode->lower_margin = vm->vfront_porch;
        fbmode->vsync_len = vm->vsync_len;

        /* prevent division by zero in KHZ2PICOS macro */
        fbmode->pixclock = vm->pixelclock ?
                        KHZ2PICOS(vm->pixelclock / 1000) : 0;

        fbmode->sync = 0;
        fbmode->vmode = 0;
        if (vm->flags & DISPLAY_FLAGS_HSYNC_HIGH)
                fbmode->sync |= FB_SYNC_HOR_HIGH_ACT;
        if (vm->flags & DISPLAY_FLAGS_VSYNC_HIGH)
                fbmode->sync |= FB_SYNC_VERT_HIGH_ACT;
        if (vm->flags & DISPLAY_FLAGS_INTERLACED)
                fbmode->vmode |= FB_VMODE_INTERLACED;
        if (vm->flags & DISPLAY_FLAGS_DOUBLESCAN)
                fbmode->vmode |= FB_VMODE_DOUBLE;
        fbmode->flag = 0;

        htotal = vm->hactive + vm->hfront_porch + vm->hback_porch +
                 vm->hsync_len;
        vtotal = vm->vactive + vm->vfront_porch + vm->vback_porch +
                 vm->vsync_len;
        /* prevent division by zero */
        if (htotal && vtotal) {
                fbmode->refresh = vm->pixelclock / (htotal * vtotal);
        /* a mode must have htotal and vtotal != 0 or it is invalid */
        } else {
                fbmode->refresh = 0;
                return -EINVAL;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(fb_videomode_from_videomode);

#ifdef CONFIG_OF
static inline void dump_fb_videomode(const struct fb_videomode *m)
{
        pr_debug("fb_videomode = %ux%u@%uHz (%ukHz) %u %u %u %u %u %u %u %u %u\n",
                 m->xres, m->yres, m->refresh, m->pixclock, m->left_margin,
                 m->right_margin, m->upper_margin, m->lower_margin,
                 m->hsync_len, m->vsync_len, m->sync, m->vmode, m->flag);
}

/**
 * of_get_fb_videomode - get a fb_videomode from devicetree
 * @np: device_node with the timing specification
 * @fb: will be set to the return value
 * @index: index into the list of display timings in devicetree
 *
 * DESCRIPTION:
 * This function is expensive and should only be used, if only one mode is to be
 * read from DT. To get multiple modes start with of_get_display_timings ond
 * work with that instead.
 */
int of_get_fb_videomode(struct device_node *np, struct fb_videomode *fb,
                        int index)
{
        struct videomode vm;
        int ret;

        ret = of_get_videomode(np, &vm, index);
        if (ret)
                return ret;

        ret = fb_videomode_from_videomode(&vm, fb);
        if (ret)
                return ret;

        pr_debug("%pOF: got %dx%d display mode\n",
                np, vm.hactive, vm.vactive);
        dump_fb_videomode(fb);

        return 0;
}
EXPORT_SYMBOL_GPL(of_get_fb_videomode);
#endif /* CONFIG_OF */
#endif /* CONFIG_VIDEOMODE_HELPERS */

#else
int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var)
{
        return 1;
}
void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
}
void fb_edid_add_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
}
void fb_destroy_modedb(struct fb_videomode *modedb)
{
}
int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var,
                struct fb_info *info)
{
        return -EINVAL;
}
#endif /* CONFIG_FB_MODE_HELPERS */

/*
 * fb_validate_mode - validates var against monitor capabilities
 * @var: pointer to fb_var_screeninfo
 * @info: pointer to fb_info
 *
 * DESCRIPTION:
 * Validates video mode against monitor capabilities specified in
 * info->monspecs.
 *
 * REQUIRES:
 * A valid info->monspecs.
 */
int fb_validate_mode(const struct fb_var_screeninfo *var, struct fb_info *info)
{
        u32 hfreq, vfreq, htotal, vtotal, pixclock;
        u32 hfmin, hfmax, vfmin, vfmax, dclkmin, dclkmax;

        /*
         * If monspecs are invalid, use values that are enough
         * for 640x480@60
         */
        if (!info->monspecs.hfmax || !info->monspecs.vfmax ||
            !info->monspecs.dclkmax ||
            info->monspecs.hfmax < info->monspecs.hfmin ||
            info->monspecs.vfmax < info->monspecs.vfmin ||
            info->monspecs.dclkmax < info->monspecs.dclkmin) {
                hfmin = 29000; hfmax = 30000;
                vfmin = 60; vfmax = 60;
                dclkmin = 0; dclkmax = 25000000;
        } else {
                hfmin = info->monspecs.hfmin;
                hfmax = info->monspecs.hfmax;
                vfmin = info->monspecs.vfmin;
                vfmax = info->monspecs.vfmax;
                dclkmin = info->monspecs.dclkmin;
                dclkmax = info->monspecs.dclkmax;
        }

        if (!var->pixclock)
                return -EINVAL;
        pixclock = PICOS2KHZ(var->pixclock) * 1000;

        htotal = var->xres + var->right_margin + var->hsync_len +
                var->left_margin;
        vtotal = var->yres + var->lower_margin + var->vsync_len +
                var->upper_margin;

        if (var->vmode & FB_VMODE_INTERLACED)
                vtotal /= 2;
        if (var->vmode & FB_VMODE_DOUBLE)
                vtotal *= 2;

        hfreq = pixclock/htotal;
        hfreq = (hfreq + 500) / 1000 * 1000;

        vfreq = hfreq/vtotal;

        return (vfreq < vfmin || vfreq > vfmax ||
                hfreq < hfmin || hfreq > hfmax ||
                pixclock < dclkmin || pixclock > dclkmax) ?
                -EINVAL : 0;
}

#if defined(CONFIG_FIRMWARE_EDID) && defined(CONFIG_X86)

/*
 * We need to ensure that the EDID block is only returned for
 * the primary graphics adapter.
 */

const unsigned char *fb_firmware_edid(struct device *device)
{
        struct pci_dev *dev = NULL;
        struct resource *res = NULL;
        unsigned char *edid = NULL;

        if (device)
                dev = to_pci_dev(device);

        if (dev)
                res = &dev->resource[PCI_ROM_RESOURCE];

        if (res && res->flags & IORESOURCE_ROM_SHADOW)
                edid = edid_info.dummy;

        return edid;
}
#else
const unsigned char *fb_firmware_edid(struct device *device)
{
        return NULL;
}
#endif
EXPORT_SYMBOL(fb_firmware_edid);

EXPORT_SYMBOL(fb_parse_edid);
EXPORT_SYMBOL(fb_edid_to_monspecs);
EXPORT_SYMBOL(fb_edid_add_monspecs);
EXPORT_SYMBOL(fb_get_mode);
EXPORT_SYMBOL(fb_validate_mode);
EXPORT_SYMBOL(fb_destroy_modedb);