/*
 * The list_sort function is (presumably) licensed under the GPL (see the
 * top level "COPYING" file for details).
 *
 * The remainder of this file is:
 *
 * Copyright © 1997-2003 by The XFree86 Project, Inc.
 * Copyright © 2007 Dave Airlie
 * Copyright © 2007-2008 Intel Corporation
 *   Jesse Barnes <jesse.barnes@intel.com>
 * Copyright 2005-2006 Luc Verhaegen
 * Copyright (c) 2001, Andy Ritger  aritger@nvidia.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Except as contained in this notice, the name of the copyright holder(s)
 * and author(s) shall not be used in advertising or otherwise to promote
 * the sale, use or other dealings in this Software without prior written
 * authorization from the copyright holder(s) and author(s).
 */

#include <linux/list.h>
#include "drmP.h"
#include "drm.h"
#include "drm_crtc.h"

/**
 * drm_mode_debug_printmodeline - debug print a mode
 * @dev: DRM device
 * @mode: mode to print
 *
 * LOCKING:
 * None.
 *
 * Describe @mode using DRM_DEBUG.
 */
void drm_mode_debug_printmodeline(struct drm_display_mode *mode)
{
        DRM_DEBUG_KMS("Modeline %d:\"%s\" %d %d %d %d %d %d %d %d %d %d "
                        "0x%x 0x%x\n",
                mode->base.id, mode->name, mode->vrefresh, mode->clock,
                mode->hdisplay, mode->hsync_start,
                mode->hsync_end, mode->htotal,
                mode->vdisplay, mode->vsync_start,
                mode->vsync_end, mode->vtotal, mode->type, mode->flags);
}
EXPORT_SYMBOL(drm_mode_debug_printmodeline);

/**
 * drm_cvt_mode -create a modeline based on CVT algorithm
 * @dev: DRM device
 * @hdisplay: hdisplay size
 * @vdisplay: vdisplay size
 * @vrefresh  : vrefresh rate
 * @reduced : Whether the GTF calculation is simplified
 * @interlaced:Whether the interlace is supported
 *
 * LOCKING:
 * none.
 *
 * return the modeline based on CVT algorithm
 *
 * This function is called to generate the modeline based on CVT algorithm
 * according to the hdisplay, vdisplay, vrefresh.
 * It is based from the VESA(TM) Coordinated Video Timing Generator by
 * Graham Loveridge April 9, 2003 available at
 * http://www.vesa.org/public/CVT/CVTd6r1.xls
 *
 * And it is copied from xf86CVTmode in xserver/hw/xfree86/modes/xf86cvt.c.
 * What I have done is to translate it by using integer calculation.
 */
#define HV_FACTOR                       1000
struct drm_display_mode *drm_cvt_mode(struct drm_device *dev, int hdisplay,
                                      int vdisplay, int vrefresh,
                                      bool reduced, bool interlaced, bool margins)
{
        /* 1) top/bottom margin size (% of height) - default: 1.8, */
#define CVT_MARGIN_PERCENTAGE           18
        /* 2) character cell horizontal granularity (pixels) - default 8 */
#define CVT_H_GRANULARITY               8
        /* 3) Minimum vertical porch (lines) - default 3 */
#define CVT_MIN_V_PORCH                 3
        /* 4) Minimum number of vertical back porch lines - default 6 */
#define CVT_MIN_V_BPORCH                6
        /* Pixel Clock step (kHz) */
#define CVT_CLOCK_STEP                  250
        struct drm_display_mode *drm_mode;
        unsigned int vfieldrate, hperiod;
        int hdisplay_rnd, hmargin, vdisplay_rnd, vmargin, vsync;
        int interlace;

        /* allocate the drm_display_mode structure. If failure, we will
         * return directly
         */
        drm_mode = drm_mode_create(dev);
        if (!drm_mode)
                return NULL;

        /* the CVT default refresh rate is 60Hz */
        if (!vrefresh)
                vrefresh = 60;

        /* the required field fresh rate */
        if (interlaced)
                vfieldrate = vrefresh * 2;
        else
                vfieldrate = vrefresh;

        /* horizontal pixels */
        hdisplay_rnd = hdisplay - (hdisplay % CVT_H_GRANULARITY);

        /* determine the left&right borders */
        hmargin = 0;
        if (margins) {
                hmargin = hdisplay_rnd * CVT_MARGIN_PERCENTAGE / 1000;
                hmargin -= hmargin % CVT_H_GRANULARITY;
        }
        /* find the total active pixels */
        drm_mode->hdisplay = hdisplay_rnd + 2 * hmargin;

        /* find the number of lines per field */
        if (interlaced)
                vdisplay_rnd = vdisplay / 2;
        else
                vdisplay_rnd = vdisplay;

        /* find the top & bottom borders */
        vmargin = 0;
        if (margins)
                vmargin = vdisplay_rnd * CVT_MARGIN_PERCENTAGE / 1000;

        drm_mode->vdisplay = vdisplay + 2 * vmargin;

        /* Interlaced */
        if (interlaced)
                interlace = 1;
        else
                interlace = 0;

        /* Determine VSync Width from aspect ratio */
        if (!(vdisplay % 3) && ((vdisplay * 4 / 3) == hdisplay))
                vsync = 4;
        else if (!(vdisplay % 9) && ((vdisplay * 16 / 9) == hdisplay))
                vsync = 5;
        else if (!(vdisplay % 10) && ((vdisplay * 16 / 10) == hdisplay))
                vsync = 6;
        else if (!(vdisplay % 4) && ((vdisplay * 5 / 4) == hdisplay))
                vsync = 7;
        else if (!(vdisplay % 9) && ((vdisplay * 15 / 9) == hdisplay))
                vsync = 7;
        else /* custom */
                vsync = 10;

        if (!reduced) {
                /* simplify the GTF calculation */
                /* 4) Minimum time of vertical sync + back porch interval (µs)
                 * default 550.0
                 */
                int tmp1, tmp2;
#define CVT_MIN_VSYNC_BP        550
                /* 3) Nominal HSync width (% of line period) - default 8 */
#define CVT_HSYNC_PERCENTAGE    8
                unsigned int hblank_percentage;
                int vsyncandback_porch, vback_porch, hblank;

                /* estimated the horizontal period */
                tmp1 = HV_FACTOR * 1000000  -
                                CVT_MIN_VSYNC_BP * HV_FACTOR * vfieldrate;
                tmp2 = (vdisplay_rnd + 2 * vmargin + CVT_MIN_V_PORCH) * 2 +
                                interlace;
                hperiod = tmp1 * 2 / (tmp2 * vfieldrate);

                tmp1 = CVT_MIN_VSYNC_BP * HV_FACTOR / hperiod + 1;
                /* 9. Find number of lines in sync + backporch */
                if (tmp1 < (vsync + CVT_MIN_V_PORCH))
                        vsyncandback_porch = vsync + CVT_MIN_V_PORCH;
                else
                        vsyncandback_porch = tmp1;
                /* 10. Find number of lines in back porch */
                vback_porch = vsyncandback_porch - vsync;
                drm_mode->vtotal = vdisplay_rnd + 2 * vmargin +
                                vsyncandback_porch + CVT_MIN_V_PORCH;
                /* 5) Definition of Horizontal blanking time limitation */
                /* Gradient (%/kHz) - default 600 */
#define CVT_M_FACTOR    600
                /* Offset (%) - default 40 */
#define CVT_C_FACTOR    40
                /* Blanking time scaling factor - default 128 */
#define CVT_K_FACTOR    128
                /* Scaling factor weighting - default 20 */
#define CVT_J_FACTOR    20
#define CVT_M_PRIME     (CVT_M_FACTOR * CVT_K_FACTOR / 256)
#define CVT_C_PRIME     ((CVT_C_FACTOR - CVT_J_FACTOR) * CVT_K_FACTOR / 256 + \
                         CVT_J_FACTOR)
                /* 12. Find ideal blanking duty cycle from formula */
                hblank_percentage = CVT_C_PRIME * HV_FACTOR - CVT_M_PRIME *
                                        hperiod / 1000;
                /* 13. Blanking time */
                if (hblank_percentage < 20 * HV_FACTOR)
                        hblank_percentage = 20 * HV_FACTOR;
                hblank = drm_mode->hdisplay * hblank_percentage /
                         (100 * HV_FACTOR - hblank_percentage);
                hblank -= hblank % (2 * CVT_H_GRANULARITY);
                /* 14. find the total pixes per line */
                drm_mode->htotal = drm_mode->hdisplay + hblank;
                drm_mode->hsync_end = drm_mode->hdisplay + hblank / 2;
                drm_mode->hsync_start = drm_mode->hsync_end -
                        (drm_mode->htotal * CVT_HSYNC_PERCENTAGE) / 100;
                drm_mode->hsync_start += CVT_H_GRANULARITY -
                        drm_mode->hsync_start % CVT_H_GRANULARITY;
                /* fill the Vsync values */
                drm_mode->vsync_start = drm_mode->vdisplay + CVT_MIN_V_PORCH;
                drm_mode->vsync_end = drm_mode->vsync_start + vsync;
        } else {
                /* Reduced blanking */
                /* Minimum vertical blanking interval time (µs)- default 460 */
#define CVT_RB_MIN_VBLANK       460
                /* Fixed number of clocks for horizontal sync */
#define CVT_RB_H_SYNC           32
                /* Fixed number of clocks for horizontal blanking */
#define CVT_RB_H_BLANK          160
                /* Fixed number of lines for vertical front porch - default 3*/
#define CVT_RB_VFPORCH          3
                int vbilines;
                int tmp1, tmp2;
                /* 8. Estimate Horizontal period. */
                tmp1 = HV_FACTOR * 1000000 -
                        CVT_RB_MIN_VBLANK * HV_FACTOR * vfieldrate;
                tmp2 = vdisplay_rnd + 2 * vmargin;
                hperiod = tmp1 / (tmp2 * vfieldrate);
                /* 9. Find number of lines in vertical blanking */
                vbilines = CVT_RB_MIN_VBLANK * HV_FACTOR / hperiod + 1;
                /* 10. Check if vertical blanking is sufficient */
                if (vbilines < (CVT_RB_VFPORCH + vsync + CVT_MIN_V_BPORCH))
                        vbilines = CVT_RB_VFPORCH + vsync + CVT_MIN_V_BPORCH;
                /* 11. Find total number of lines in vertical field */
                drm_mode->vtotal = vdisplay_rnd + 2 * vmargin + vbilines;
                /* 12. Find total number of pixels in a line */
                drm_mode->htotal = drm_mode->hdisplay + CVT_RB_H_BLANK;
                /* Fill in HSync values */
                drm_mode->hsync_end = drm_mode->hdisplay + CVT_RB_H_BLANK / 2;
                drm_mode->hsync_start = drm_mode->hsync_end = CVT_RB_H_SYNC;
        }
        /* 15/13. Find pixel clock frequency (kHz for xf86) */
        drm_mode->clock = drm_mode->htotal * HV_FACTOR * 1000 / hperiod;
        drm_mode->clock -= drm_mode->clock % CVT_CLOCK_STEP;
        /* 18/16. Find actual vertical frame frequency */
        /* ignore - just set the mode flag for interlaced */
        if (interlaced)
                drm_mode->vtotal *= 2;
        /* Fill the mode line name */
        drm_mode_set_name(drm_mode);
        if (reduced)
                drm_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
                                        DRM_MODE_FLAG_NVSYNC);
        else
                drm_mode->flags |= (DRM_MODE_FLAG_PVSYNC |
                                        DRM_MODE_FLAG_NHSYNC);
        if (interlaced)
                drm_mode->flags |= DRM_MODE_FLAG_INTERLACE;

    return drm_mode;
}
EXPORT_SYMBOL(drm_cvt_mode);

/**
 * drm_gtf_mode - create the modeline based on GTF algorithm
 *
 * @dev         :drm device
 * @hdisplay    :hdisplay size
 * @vdisplay    :vdisplay size
 * @vrefresh    :vrefresh rate.
 * @interlaced  :whether the interlace is supported
 * @margins     :whether the margin is supported
 *
 * LOCKING.
 * none.
 *
 * return the modeline based on GTF algorithm
 *
 * This function is to create the modeline based on the GTF algorithm.
 * Generalized Timing Formula is derived from:
 *      GTF Spreadsheet by Andy Morrish (1/5/97)
 *      available at http://www.vesa.org
 *
 * And it is copied from the file of xserver/hw/xfree86/modes/xf86gtf.c.
 * What I have done is to translate it by using integer calculation.
 * I also refer to the function of fb_get_mode in the file of
 * drivers/video/fbmon.c
 */
struct drm_display_mode *drm_gtf_mode(struct drm_device *dev, int hdisplay,
                                      int vdisplay, int vrefresh,
                                      bool interlaced, int margins)
{
        /* 1) top/bottom margin size (% of height) - default: 1.8, */
#define GTF_MARGIN_PERCENTAGE           18
        /* 2) character cell horizontal granularity (pixels) - default 8 */
#define GTF_CELL_GRAN                   8
        /* 3) Minimum vertical porch (lines) - default 3 */
#define GTF_MIN_V_PORCH                 1
        /* width of vsync in lines */
#define V_SYNC_RQD                      3
        /* width of hsync as % of total line */
#define H_SYNC_PERCENT                  8
        /* min time of vsync + back porch (microsec) */
#define MIN_VSYNC_PLUS_BP               550
        /* blanking formula gradient */
#define GTF_M                           600
        /* blanking formula offset */
#define GTF_C                           40
        /* blanking formula scaling factor */
#define GTF_K                           128
        /* blanking formula scaling factor */
#define GTF_J                           20
        /* C' and M' are part of the Blanking Duty Cycle computation */
#define GTF_C_PRIME             (((GTF_C - GTF_J) * GTF_K / 256) + GTF_J)
#define GTF_M_PRIME             (GTF_K * GTF_M / 256)
        struct drm_display_mode *drm_mode;
        unsigned int hdisplay_rnd, vdisplay_rnd, vfieldrate_rqd;
        int top_margin, bottom_margin;
        int interlace;
        unsigned int hfreq_est;
        int vsync_plus_bp, vback_porch;
        unsigned int vtotal_lines, vfieldrate_est, hperiod;
        unsigned int vfield_rate, vframe_rate;
        int left_margin, right_margin;
        unsigned int total_active_pixels, ideal_duty_cycle;
        unsigned int hblank, total_pixels, pixel_freq;
        int hsync, hfront_porch, vodd_front_porch_lines;
        unsigned int tmp1, tmp2;

        drm_mode = drm_mode_create(dev);
        if (!drm_mode)
                return NULL;

        /* 1. In order to give correct results, the number of horizontal
         * pixels requested is first processed to ensure that it is divisible
         * by the character size, by rounding it to the nearest character
         * cell boundary:
         */
        hdisplay_rnd = (hdisplay + GTF_CELL_GRAN / 2) / GTF_CELL_GRAN;
        hdisplay_rnd = hdisplay_rnd * GTF_CELL_GRAN;

        /* 2. If interlace is requested, the number of vertical lines assumed
         * by the calculation must be halved, as the computation calculates
         * the number of vertical lines per field.
         */
        if (interlaced)
                vdisplay_rnd = vdisplay / 2;
        else
                vdisplay_rnd = vdisplay;

        /* 3. Find the frame rate required: */
        if (interlaced)
                vfieldrate_rqd = vrefresh * 2;
        else
                vfieldrate_rqd = vrefresh;

        /* 4. Find number of lines in Top margin: */
        top_margin = 0;
        if (margins)
                top_margin = (vdisplay_rnd * GTF_MARGIN_PERCENTAGE + 500) /
                                1000;
        /* 5. Find number of lines in bottom margin: */
        bottom_margin = top_margin;

        /* 6. If interlace is required, then set variable interlace: */
        if (interlaced)
                interlace = 1;
        else
                interlace = 0;

        /* 7. Estimate the Horizontal frequency */
        {
                tmp1 = (1000000  - MIN_VSYNC_PLUS_BP * vfieldrate_rqd) / 500;
                tmp2 = (vdisplay_rnd + 2 * top_margin + GTF_MIN_V_PORCH) *
                                2 + interlace;
                hfreq_est = (tmp2 * 1000 * vfieldrate_rqd) / tmp1;
        }

        /* 8. Find the number of lines in V sync + back porch */
        /* [V SYNC+BP] = RINT(([MIN VSYNC+BP] * hfreq_est / 1000000)) */
        vsync_plus_bp = MIN_VSYNC_PLUS_BP * hfreq_est / 1000;
        vsync_plus_bp = (vsync_plus_bp + 500) / 1000;
        /*  9. Find the number of lines in V back porch alone: */
        vback_porch = vsync_plus_bp - V_SYNC_RQD;
        /*  10. Find the total number of lines in Vertical field period: */
        vtotal_lines = vdisplay_rnd + top_margin + bottom_margin +
                        vsync_plus_bp + GTF_MIN_V_PORCH;
        /*  11. Estimate the Vertical field frequency: */
        vfieldrate_est = hfreq_est / vtotal_lines;
        /*  12. Find the actual horizontal period: */
        hperiod = 1000000 / (vfieldrate_rqd * vtotal_lines);

        /*  13. Find the actual Vertical field frequency: */
        vfield_rate = hfreq_est / vtotal_lines;
        /*  14. Find the Vertical frame frequency: */
        if (interlaced)
                vframe_rate = vfield_rate / 2;
        else
                vframe_rate = vfield_rate;
        /*  15. Find number of pixels in left margin: */
        if (margins)
                left_margin = (hdisplay_rnd * GTF_MARGIN_PERCENTAGE + 500) /
                                1000;
        else
                left_margin = 0;

        /* 16.Find number of pixels in right margin: */
        right_margin = left_margin;
        /* 17.Find total number of active pixels in image and left and right */
        total_active_pixels = hdisplay_rnd + left_margin + right_margin;
        /* 18.Find the ideal blanking duty cycle from blanking duty cycle */
        ideal_duty_cycle = GTF_C_PRIME * 1000 -
                                (GTF_M_PRIME * 1000000 / hfreq_est);
        /* 19.Find the number of pixels in the blanking time to the nearest
         * double character cell: */
        hblank = total_active_pixels * ideal_duty_cycle /
                        (100000 - ideal_duty_cycle);
        hblank = (hblank + GTF_CELL_GRAN) / (2 * GTF_CELL_GRAN);
        hblank = hblank * 2 * GTF_CELL_GRAN;
        /* 20.Find total number of pixels: */
        total_pixels = total_active_pixels + hblank;
        /* 21.Find pixel clock frequency: */
        pixel_freq = total_pixels * hfreq_est / 1000;
        /* Stage 1 computations are now complete; I should really pass
         * the results to another function and do the Stage 2 computations,
         * but I only need a few more values so I'll just append the
         * computations here for now */
        /* 17. Find the number of pixels in the horizontal sync period: */
        hsync = H_SYNC_PERCENT * total_pixels / 100;
        hsync = (hsync + GTF_CELL_GRAN / 2) / GTF_CELL_GRAN;
        hsync = hsync * GTF_CELL_GRAN;
        /* 18. Find the number of pixels in horizontal front porch period */
        hfront_porch = hblank / 2 - hsync;
        /*  36. Find the number of lines in the odd front porch period: */
        vodd_front_porch_lines = GTF_MIN_V_PORCH ;

        /* finally, pack the results in the mode struct */
        drm_mode->hdisplay = hdisplay_rnd;
        drm_mode->hsync_start = hdisplay_rnd + hfront_porch;
        drm_mode->hsync_end = drm_mode->hsync_start + hsync;
        drm_mode->htotal = total_pixels;
        drm_mode->vdisplay = vdisplay_rnd;
        drm_mode->vsync_start = vdisplay_rnd + vodd_front_porch_lines;
        drm_mode->vsync_end = drm_mode->vsync_start + V_SYNC_RQD;
        drm_mode->vtotal = vtotal_lines;

        drm_mode->clock = pixel_freq;

        drm_mode_set_name(drm_mode);
        drm_mode->flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC;

        if (interlaced) {
                drm_mode->vtotal *= 2;
                drm_mode->flags |= DRM_MODE_FLAG_INTERLACE;
        }

        return drm_mode;
}
EXPORT_SYMBOL(drm_gtf_mode);
/**
 * drm_mode_set_name - set the name on a mode
 * @mode: name will be set in this mode
 *
 * LOCKING:
 * None.
 *
 * Set the name of @mode to a standard format.
 */
void drm_mode_set_name(struct drm_display_mode *mode)
{
        snprintf(mode->name, DRM_DISPLAY_MODE_LEN, "%dx%d", mode->hdisplay,
                 mode->vdisplay);
}
EXPORT_SYMBOL(drm_mode_set_name);

/**
 * drm_mode_list_concat - move modes from one list to another
 * @head: source list
 * @new: dst list
 *
 * LOCKING:
 * Caller must ensure both lists are locked.
 *
 * Move all the modes from @head to @new.
 */
void drm_mode_list_concat(struct list_head *head, struct list_head *new)
{

        struct list_head *entry, *tmp;

        list_for_each_safe(entry, tmp, head) {
                list_move_tail(entry, new);
        }
}
EXPORT_SYMBOL(drm_mode_list_concat);

/**
 * drm_mode_width - get the width of a mode
 * @mode: mode
 *
 * LOCKING:
 * None.
 *
 * Return @mode's width (hdisplay) value.
 *
 * FIXME: is this needed?
 *
 * RETURNS:
 * @mode->hdisplay
 */
int drm_mode_width(struct drm_display_mode *mode)
{
        return mode->hdisplay;

}
EXPORT_SYMBOL(drm_mode_width);

/**
 * drm_mode_height - get the height of a mode
 * @mode: mode
 *
 * LOCKING:
 * None.
 *
 * Return @mode's height (vdisplay) value.
 *
 * FIXME: is this needed?
 *
 * RETURNS:
 * @mode->vdisplay
 */
int drm_mode_height(struct drm_display_mode *mode)
{
        return mode->vdisplay;
}
EXPORT_SYMBOL(drm_mode_height);

/**
 * drm_mode_vrefresh - get the vrefresh of a mode
 * @mode: mode
 *
 * LOCKING:
 * None.
 *
 * Return @mode's vrefresh rate or calculate it if necessary.
 *
 * FIXME: why is this needed?  shouldn't vrefresh be set already?
 *
 * RETURNS:
 * Vertical refresh rate. It will be the result of actual value plus 0.5.
 * If it is 70.288, it will return 70Hz.
 * If it is 59.6, it will return 60Hz.
 */
int drm_mode_vrefresh(struct drm_display_mode *mode)
{
        int refresh = 0;
        unsigned int calc_val;

        if (mode->vrefresh > 0)
                refresh = mode->vrefresh;
        else if (mode->htotal > 0 && mode->vtotal > 0) {
                int vtotal;
                vtotal = mode->vtotal;
                /* work out vrefresh the value will be x1000 */
                calc_val = (mode->clock * 1000);
                calc_val /= mode->htotal;
                refresh = (calc_val + vtotal / 2) / vtotal;

                if (mode->flags & DRM_MODE_FLAG_INTERLACE)
                        refresh *= 2;
                if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
                        refresh /= 2;
                if (mode->vscan > 1)
                        refresh /= mode->vscan;
        }
        return refresh;
}
EXPORT_SYMBOL(drm_mode_vrefresh);

/**
 * drm_mode_set_crtcinfo - set CRTC modesetting parameters
 * @p: mode
 * @adjust_flags: unused? (FIXME)
 *
 * LOCKING:
 * None.
 *
 * Setup the CRTC modesetting parameters for @p, adjusting if necessary.
 */
void drm_mode_set_crtcinfo(struct drm_display_mode *p, int adjust_flags)
{
        if ((p == NULL) || ((p->type & DRM_MODE_TYPE_CRTC_C) == DRM_MODE_TYPE_BUILTIN))
                return;

        p->crtc_hdisplay = p->hdisplay;
        p->crtc_hsync_start = p->hsync_start;
        p->crtc_hsync_end = p->hsync_end;
        p->crtc_htotal = p->htotal;
        p->crtc_hskew = p->hskew;
        p->crtc_vdisplay = p->vdisplay;
        p->crtc_vsync_start = p->vsync_start;
        p->crtc_vsync_end = p->vsync_end;
        p->crtc_vtotal = p->vtotal;

        if (p->flags & DRM_MODE_FLAG_INTERLACE) {
                if (adjust_flags & CRTC_INTERLACE_HALVE_V) {
                        p->crtc_vdisplay /= 2;
                        p->crtc_vsync_start /= 2;
                        p->crtc_vsync_end /= 2;
                        p->crtc_vtotal /= 2;
                }

                p->crtc_vtotal |= 1;
        }

        if (p->flags & DRM_MODE_FLAG_DBLSCAN) {
                p->crtc_vdisplay *= 2;
                p->crtc_vsync_start *= 2;
                p->crtc_vsync_end *= 2;
                p->crtc_vtotal *= 2;
        }

        if (p->vscan > 1) {
                p->crtc_vdisplay *= p->vscan;
                p->crtc_vsync_start *= p->vscan;
                p->crtc_vsync_end *= p->vscan;
                p->crtc_vtotal *= p->vscan;
        }

        p->crtc_vblank_start = min(p->crtc_vsync_start, p->crtc_vdisplay);
        p->crtc_vblank_end = max(p->crtc_vsync_end, p->crtc_vtotal);
        p->crtc_hblank_start = min(p->crtc_hsync_start, p->crtc_hdisplay);
        p->crtc_hblank_end = max(p->crtc_hsync_end, p->crtc_htotal);

        p->crtc_hadjusted = false;
        p->crtc_vadjusted = false;
}
EXPORT_SYMBOL(drm_mode_set_crtcinfo);


/**
 * drm_mode_duplicate - allocate and duplicate an existing mode
 * @m: mode to duplicate
 *
 * LOCKING:
 * None.
 *
 * Just allocate a new mode, copy the existing mode into it, and return
 * a pointer to it.  Used to create new instances of established modes.
 */
struct drm_display_mode *drm_mode_duplicate(struct drm_device *dev,
                                            struct drm_display_mode *mode)
{
        struct drm_display_mode *nmode;
        int new_id;

        nmode = drm_mode_create(dev);
        if (!nmode)
                return NULL;

        new_id = nmode->base.id;
        *nmode = *mode;
        nmode->base.id = new_id;
        INIT_LIST_HEAD(&nmode->head);
        return nmode;
}
EXPORT_SYMBOL(drm_mode_duplicate);

/**
 * drm_mode_equal - test modes for equality
 * @mode1: first mode
 * @mode2: second mode
 *
 * LOCKING:
 * None.
 *
 * Check to see if @mode1 and @mode2 are equivalent.
 *
 * RETURNS:
 * True if the modes are equal, false otherwise.
 */
bool drm_mode_equal(struct drm_display_mode *mode1, struct drm_display_mode *mode2)
{
        /* do clock check convert to PICOS so fb modes get matched
         * the same */
        if (mode1->clock && mode2->clock) {
                if (KHZ2PICOS(mode1->clock) != KHZ2PICOS(mode2->clock))
                        return false;
        } else if (mode1->clock != mode2->clock)
                return false;

        if (mode1->hdisplay == mode2->hdisplay &&
            mode1->hsync_start == mode2->hsync_start &&
            mode1->hsync_end == mode2->hsync_end &&
            mode1->htotal == mode2->htotal &&
            mode1->hskew == mode2->hskew &&
            mode1->vdisplay == mode2->vdisplay &&
            mode1->vsync_start == mode2->vsync_start &&
            mode1->vsync_end == mode2->vsync_end &&
            mode1->vtotal == mode2->vtotal &&
            mode1->vscan == mode2->vscan &&
            mode1->flags == mode2->flags)
                return true;

        return false;
}
EXPORT_SYMBOL(drm_mode_equal);

/**
 * drm_mode_validate_size - make sure modes adhere to size constraints
 * @dev: DRM device
 * @mode_list: list of modes to check
 * @maxX: maximum width
 * @maxY: maximum height
 * @maxPitch: max pitch
 *
 * LOCKING:
 * Caller must hold a lock protecting @mode_list.
 *
 * The DRM device (@dev) has size and pitch limits.  Here we validate the
 * modes we probed for @dev against those limits and set their status as
 * necessary.
 */
void drm_mode_validate_size(struct drm_device *dev,
                            struct list_head *mode_list,
                            int maxX, int maxY, int maxPitch)
{
        struct drm_display_mode *mode;

        list_for_each_entry(mode, mode_list, head) {
                if (maxPitch > 0 && mode->hdisplay > maxPitch)
                        mode->status = MODE_BAD_WIDTH;

                if (maxX > 0 && mode->hdisplay > maxX)
                        mode->status = MODE_VIRTUAL_X;

                if (maxY > 0 && mode->vdisplay > maxY)
                        mode->status = MODE_VIRTUAL_Y;
        }
}
EXPORT_SYMBOL(drm_mode_validate_size);

/**
 * drm_mode_validate_clocks - validate modes against clock limits
 * @dev: DRM device
 * @mode_list: list of modes to check
 * @min: minimum clock rate array
 * @max: maximum clock rate array
 * @n_ranges: number of clock ranges (size of arrays)
 *
 * LOCKING:
 * Caller must hold a lock protecting @mode_list.
 *
 * Some code may need to check a mode list against the clock limits of the
 * device in question.  This function walks the mode list, testing to make
 * sure each mode falls within a given range (defined by @min and @max
 * arrays) and sets @mode->status as needed.
 */
void drm_mode_validate_clocks(struct drm_device *dev,
                              struct list_head *mode_list,
                              int *min, int *max, int n_ranges)
{
        struct drm_display_mode *mode;
        int i;

        list_for_each_entry(mode, mode_list, head) {
                bool good = false;
                for (i = 0; i < n_ranges; i++) {
                        if (mode->clock >= min[i] && mode->clock <= max[i]) {
                                good = true;
                                break;
                        }
                }
                if (!good)
                        mode->status = MODE_CLOCK_RANGE;
        }
}
EXPORT_SYMBOL(drm_mode_validate_clocks);

/**
 * drm_mode_prune_invalid - remove invalid modes from mode list
 * @dev: DRM device
 * @mode_list: list of modes to check
 * @verbose: be verbose about it
 *
 * LOCKING:
 * Caller must hold a lock protecting @mode_list.
 *
 * Once mode list generation is complete, a caller can use this routine to
 * remove invalid modes from a mode list.  If any of the modes have a
 * status other than %MODE_OK, they are removed from @mode_list and freed.
 */
void drm_mode_prune_invalid(struct drm_device *dev,
                            struct list_head *mode_list, bool verbose)
{
        struct drm_display_mode *mode, *t;

        list_for_each_entry_safe(mode, t, mode_list, head) {
                if (mode->status != MODE_OK) {
                        list_del(&mode->head);
                        if (verbose) {
                                drm_mode_debug_printmodeline(mode);
                                DRM_DEBUG_KMS("Not using %s mode %d\n",
                                        mode->name, mode->status);
                        }
                        drm_mode_destroy(dev, mode);
                }
        }
}
EXPORT_SYMBOL(drm_mode_prune_invalid);

/**
 * drm_mode_compare - compare modes for favorability
 * @lh_a: list_head for first mode
 * @lh_b: list_head for second mode
 *
 * LOCKING:
 * None.
 *
 * Compare two modes, given by @lh_a and @lh_b, returning a value indicating
 * which is better.
 *
 * RETURNS:
 * Negative if @lh_a is better than @lh_b, zero if they're equivalent, or
 * positive if @lh_b is better than @lh_a.
 */
static int drm_mode_compare(struct list_head *lh_a, struct list_head *lh_b)
{
        struct drm_display_mode *a = list_entry(lh_a, struct drm_display_mode, head);
        struct drm_display_mode *b = list_entry(lh_b, struct drm_display_mode, head);
        int diff;

        diff = ((b->type & DRM_MODE_TYPE_PREFERRED) != 0) -
                ((a->type & DRM_MODE_TYPE_PREFERRED) != 0);
        if (diff)
                return diff;
        diff = b->hdisplay * b->vdisplay - a->hdisplay * a->vdisplay;
        if (diff)
                return diff;
        diff = b->clock - a->clock;
        return diff;
}

/* FIXME: what we don't have a list sort function? */
/* list sort from Mark J Roberts (mjr@znex.org) */
void list_sort(struct list_head *head,
               int (*cmp)(struct list_head *a, struct list_head *b))
{
        struct list_head *p, *q, *e, *list, *tail, *oldhead;
        int insize, nmerges, psize, qsize, i;

        list = head->next;
        list_del(head);
        insize = 1;
        for (;;) {
                p = oldhead = list;
                list = tail = NULL;
                nmerges = 0;

                while (p) {
                        nmerges++;
                        q = p;
                        psize = 0;
                        for (i = 0; i < insize; i++) {
                                psize++;
                                q = q->next == oldhead ? NULL : q->next;
                                if (!q)
                                        break;
                        }

                        qsize = insize;
                        while (psize > 0 || (qsize > 0 && q)) {
                                if (!psize) {
                                        e = q;
                                        q = q->next;
                                        qsize--;
                                        if (q == oldhead)
                                                q = NULL;
                                } else if (!qsize || !q) {
                                        e = p;
                                        p = p->next;
                                        psize--;
                                        if (p == oldhead)
                                                p = NULL;
                                } else if (cmp(p, q) <= 0) {
                                        e = p;
                                        p = p->next;
                                        psize--;
                                        if (p == oldhead)
                                                p = NULL;
                                } else {
                                        e = q;
                                        q = q->next;
                                        qsize--;
                                        if (q == oldhead)
                                                q = NULL;
                                }
                                if (tail)
                                        tail->next = e;
                                else
                                        list = e;
                                e->prev = tail;
                                tail = e;
                        }
                        p = q;
                }

                tail->next = list;
                list->prev = tail;

                if (nmerges <= 1)
                        break;

                insize *= 2;
        }

        head->next = list;
        head->prev = list->prev;
        list->prev->next = head;
        list->prev = head;
}

/**
 * drm_mode_sort - sort mode list
 * @mode_list: list to sort
 *
 * LOCKING:
 * Caller must hold a lock protecting @mode_list.
 *
 * Sort @mode_list by favorability, putting good modes first.
 */
void drm_mode_sort(struct list_head *mode_list)
{
        list_sort(mode_list, drm_mode_compare);
}
EXPORT_SYMBOL(drm_mode_sort);

/**
 * drm_mode_connector_list_update - update the mode list for the connector
 * @connector: the connector to update
 *
 * LOCKING:
 * Caller must hold a lock protecting @mode_list.
 *
 * This moves the modes from the @connector probed_modes list
 * to the actual mode list. It compares the probed mode against the current
 * list and only adds different modes. All modes unverified after this point
 * will be removed by the prune invalid modes.
 */
void drm_mode_connector_list_update(struct drm_connector *connector)
{
        struct drm_display_mode *mode;
        struct drm_display_mode *pmode, *pt;
        int found_it;

        list_for_each_entry_safe(pmode, pt, &connector->probed_modes,
                                 head) {
                found_it = 0;
                /* go through current modes checking for the new probed mode */
                list_for_each_entry(mode, &connector->modes, head) {
                        if (drm_mode_equal(pmode, mode)) {
                                found_it = 1;
                                /* if equal delete the probed mode */
                                mode->status = pmode->status;
                                /* Merge type bits together */
                                mode->type |= pmode->type;
                                list_del(&pmode->head);
                                drm_mode_destroy(connector->dev, pmode);
                                break;
                        }
                }

                if (!found_it) {
                        list_move_tail(&pmode->head, &connector->modes);
                }
        }
}
EXPORT_SYMBOL(drm_mode_connector_list_update);