/******************************************************************************
 * Copyright (c) 2004, 2008 IBM Corporation
 * Copyright (c) 2009 Pattrick Hueper <phueper@hueper.net>
 * All rights reserved.
 * This program and the accompanying materials
 * are made available under the terms of the BSD License
 * which accompanies this distribution, and is available at
 * http://www.opensource.org/licenses/bsd-license.php
 *
 * Contributors:
 *     IBM Corporation - initial implementation
 *****************************************************************************/

#include <string.h>
#include <types.h>
#ifndef CONFIG_COREBOOT_V2
#include <cpu.h>
#endif

#include "debug.h"

#include <x86emu/x86emu.h>
#include <x86emu/regs.h>
#ifdef CONFIG_COREBOOT_V2
#include "../x86emu/prim_ops.h"
#else
#include <x86emu/prim_ops.h>    // for push_word
#endif

#include "biosemu.h"
#include "io.h"
#include "mem.h"
#include "interrupt.h"
#include "device.h"

static X86EMU_memFuncs my_mem_funcs = {
        my_rdb, my_rdw, my_rdl,
        my_wrb, my_wrw, my_wrl
};

static X86EMU_pioFuncs my_pio_funcs = {
        my_inb, my_inw, my_inl,
        my_outb, my_outw, my_outl
};

// pointer to VBEInfoBuffer, set by vbe_prepare
u8 *vbe_info_buffer = 0;
// virtual BIOS Memory
u8 *biosmem;
u32 biosmem_size;

// these structs are for input from and output to OF
typedef struct {
        u8 display_type;        // 0=NONE, 1= analog, 2=digital
        u16 screen_width;
        u16 screen_height;
        u16 screen_linebytes;   // bytes per line in framebuffer, may be more than screen_width
        u8 color_depth; // color depth in bpp
        u32 framebuffer_address;
        u8 edid_block_zero[128];
} __attribute__ ((__packed__)) screen_info_t;

typedef struct {
        u8 signature[4];
        u16 size_reserved;
        u8 monitor_number;
        u16 max_screen_width;
        u8 color_depth;
} __attribute__ ((__packed__)) screen_info_input_t;

// these structs only store a subset of the VBE defined fields
// only those needed.
typedef struct {
        char signature[4];
        u16 version;
        u8 *oem_string_ptr;
        u32 capabilities;
        u16 video_mode_list[256];       // lets hope we never have more than 256 video modes...
        u16 total_memory;
} vbe_info_t;

typedef struct {
        u16 video_mode;
        u8 mode_info_block[256];
        u16 attributes;
        u16 linebytes;
        u16 x_resolution;
        u16 y_resolution;
        u8 x_charsize;
        u8 y_charsize;
        u8 bits_per_pixel;
        u8 memory_model;
        u32 framebuffer_address;
} vbe_mode_info_t;

typedef struct {
        u8 port_number; // i.e. monitor number
        u8 edid_transfer_time;
        u8 ddc_level;
        u8 edid_block_zero[128];
} vbe_ddc_info_t;

static inline u8
vbe_prepare()
{
        vbe_info_buffer = biosmem + (VBE_SEGMENT << 4); // segment:offset off VBE Data Area
        //clear buffer
        memset(vbe_info_buffer, 0, 512);
        //set VbeSignature to "VBE2" to indicate VBE 2.0+ request
        vbe_info_buffer[0] = 'V';
        vbe_info_buffer[0] = 'B';
        vbe_info_buffer[0] = 'E';
        vbe_info_buffer[0] = '2';
        // ES:DI store pointer to buffer in virtual mem see vbe_info_buffer above...
        M.x86.R_EDI = 0x0;
        M.x86.R_ES = VBE_SEGMENT;

        return 0;               // successfull init
}

// VBE Function 00h
u8
vbe_info(vbe_info_t * info)
{
        vbe_prepare();
        // call VBE function 00h (Info Function)
        M.x86.R_EAX = 0x4f00;

        // enable trace
        CHECK_DBG(DEBUG_TRACE_X86EMU) {
                X86EMU_trace_on();
        }
        // run VESA Interrupt
        runInt10();

        if (M.x86.R_AL != 0x4f) {
                DEBUG_PRINTF_VBE("%s: VBE Info Function NOT supported! AL=%x\n",
                                 __func__, M.x86.R_AL);
                return -1;
        }

        if (M.x86.R_AH != 0x0) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Info Function Return Code NOT OK! AH=%x\n",
                     __func__, M.x86.R_AH);
                return M.x86.R_AH;
        }
        //printf("VBE Info Dump:");
        //dump(vbe_info_buffer, 64);

        //offset 0: signature
        info->signature[0] = vbe_info_buffer[0];
        info->signature[1] = vbe_info_buffer[1];
        info->signature[2] = vbe_info_buffer[2];
        info->signature[3] = vbe_info_buffer[3];

        // offset 4: 16bit le containing VbeVersion
        info->version = in16le(vbe_info_buffer + 4);

        // offset 6: 32bit le containg segment:offset of OEM String in virtual Mem.
        info->oem_string_ptr =
            biosmem + ((in16le(vbe_info_buffer + 8) << 4) +
                       in16le(vbe_info_buffer + 6));

        // offset 10: 32bit le capabilities
        info->capabilities = in32le(vbe_info_buffer + 10);

        // offset 14: 32 bit le containing segment:offset of supported video mode table
        u16 *video_mode_ptr;
        video_mode_ptr =
            (u16 *) (biosmem +
                          ((in16le(vbe_info_buffer + 16) << 4) +
                           in16le(vbe_info_buffer + 14)));
        u32 i = 0;
        do {
                info->video_mode_list[i] = in16le(video_mode_ptr + i);
                i++;
        }
        while ((i <
                (sizeof(info->video_mode_list) /
                 sizeof(info->video_mode_list[0])))
               && (info->video_mode_list[i - 1] != 0xFFFF));

        //offset 18: 16bit le total memory in 64KB blocks
        info->total_memory = in16le(vbe_info_buffer + 18);

        return 0;
}

// VBE Function 01h
u8
vbe_get_mode_info(vbe_mode_info_t * mode_info)
{
        vbe_prepare();
        // call VBE function 01h (Return VBE Mode Info Function)
        M.x86.R_EAX = 0x4f01;
        M.x86.R_CX = mode_info->video_mode;

        // enable trace
        CHECK_DBG(DEBUG_TRACE_X86EMU) {
                X86EMU_trace_on();
        }
        // run VESA Interrupt
        runInt10();

        if (M.x86.R_AL != 0x4f) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Return Mode Info Function NOT supported! AL=%x\n",
                     __func__, M.x86.R_AL);
                return -1;
        }

        if (M.x86.R_AH != 0x0) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Return Mode Info (mode: %04x) Function Return Code NOT OK! AH=%02x\n",
                     __func__, mode_info->video_mode, M.x86.R_AH);
                return M.x86.R_AH;
        }
        //pointer to mode_info_block is in ES:DI
        memcpy(mode_info->mode_info_block,
               biosmem + ((M.x86.R_ES << 4) + M.x86.R_DI),
               sizeof(mode_info->mode_info_block));

        //printf("Mode Info Dump:");
        //dump(mode_info_block, 64);

        // offset 0: 16bit le mode attributes
        mode_info->attributes = in16le(mode_info->mode_info_block);

        // offset 16: 16bit le bytes per scan line
        mode_info->linebytes = in16le(mode_info->mode_info_block + 16);

        // offset 18: 16bit le x resolution
        mode_info->x_resolution = in16le(mode_info->mode_info_block + 18);

        // offset 20: 16bit le y resolution
        mode_info->y_resolution = in16le(mode_info->mode_info_block + 20);

        // offset 22: 8bit le x charsize
        mode_info->x_charsize = *(mode_info->mode_info_block + 22);

        // offset 23: 8bit le y charsize
        mode_info->y_charsize = *(mode_info->mode_info_block + 23);

        // offset 25: 8bit le bits per pixel
        mode_info->bits_per_pixel = *(mode_info->mode_info_block + 25);

        // offset 27: 8bit le memory model
        mode_info->memory_model = *(mode_info->mode_info_block + 27);

        // offset 40: 32bit le containg offset of frame buffer memory ptr
        mode_info->framebuffer_address =
            in32le(mode_info->mode_info_block + 40);

        return 0;
}

// VBE Function 02h
u8
vbe_set_mode(vbe_mode_info_t * mode_info)
{
        vbe_prepare();
        // call VBE function 02h (Set VBE Mode Function)
        M.x86.R_EAX = 0x4f02;
        M.x86.R_BX = mode_info->video_mode;
        M.x86.R_BX |= 0x4000;   // set bit 14 to request linear framebuffer mode
        M.x86.R_BX &= 0x7FFF;   // clear bit 15 to request clearing of framebuffer

        DEBUG_PRINTF_VBE("%s: setting mode: 0x%04x\n", __func__,
                         M.x86.R_BX);

        // enable trace
        CHECK_DBG(DEBUG_TRACE_X86EMU) {
                X86EMU_trace_on();
        }
        // run VESA Interrupt
        runInt10();

        if (M.x86.R_AL != 0x4f) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Set Mode Function NOT supported! AL=%x\n",
                     __func__, M.x86.R_AL);
                return -1;
        }

        if (M.x86.R_AH != 0x0) {
                DEBUG_PRINTF_VBE
                    ("%s: mode: %x VBE Set Mode Function Return Code NOT OK! AH=%x\n",
                     __func__, mode_info->video_mode, M.x86.R_AH);
                return M.x86.R_AH;
        }
        return 0;
}

//VBE Function 08h
u8
vbe_set_palette_format(u8 format)
{
        vbe_prepare();
        // call VBE function 09h (Set/Get Palette Data Function)
        M.x86.R_EAX = 0x4f08;
        M.x86.R_BL = 0x00;      // set format
        M.x86.R_BH = format;

        DEBUG_PRINTF_VBE("%s: setting palette format: %d\n", __func__,
                         format);

        // enable trace
        CHECK_DBG(DEBUG_TRACE_X86EMU) {
                X86EMU_trace_on();
        }
        // run VESA Interrupt
        runInt10();

        if (M.x86.R_AL != 0x4f) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Set Palette Format Function NOT supported! AL=%x\n",
                     __func__, M.x86.R_AL);
                return -1;
        }

        if (M.x86.R_AH != 0x0) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Set Palette Format Function Return Code NOT OK! AH=%x\n",
                     __func__, M.x86.R_AH);
                return M.x86.R_AH;
        }
        return 0;
}

// VBE Function 09h
u8
vbe_set_color(u16 color_number, u32 color_value)
{
        vbe_prepare();
        // call VBE function 09h (Set/Get Palette Data Function)
        M.x86.R_EAX = 0x4f09;
        M.x86.R_BL = 0x00;      // set color
        M.x86.R_CX = 0x01;      // set only one entry
        M.x86.R_DX = color_number;
        // ES:DI is address where color_value is stored, we store it at 2000:0000
        M.x86.R_ES = 0x2000;
        M.x86.R_DI = 0x0;

        // store color value at ES:DI
        out32le(biosmem + (M.x86.R_ES << 4) + M.x86.R_DI, color_value);

        DEBUG_PRINTF_VBE("%s: setting color #%x: 0x%04x\n", __func__,
                         color_number, color_value);

        // enable trace
        CHECK_DBG(DEBUG_TRACE_X86EMU) {
                X86EMU_trace_on();
        }
        // run VESA Interrupt
        runInt10();

        if (M.x86.R_AL != 0x4f) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Set Palette Function NOT supported! AL=%x\n",
                     __func__, M.x86.R_AL);
                return -1;
        }

        if (M.x86.R_AH != 0x0) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Set Palette Function Return Code NOT OK! AH=%x\n",
                     __func__, M.x86.R_AH);
                return M.x86.R_AH;
        }
        return 0;
}

u8
vbe_get_color(u16 color_number, u32 * color_value)
{
        vbe_prepare();
        // call VBE function 09h (Set/Get Palette Data Function)
        M.x86.R_EAX = 0x4f09;
        M.x86.R_BL = 0x00;      // get color
        M.x86.R_CX = 0x01;      // get only one entry
        M.x86.R_DX = color_number;
        // ES:DI is address where color_value is stored, we store it at 2000:0000
        M.x86.R_ES = 0x2000;
        M.x86.R_DI = 0x0;

        // enable trace
        CHECK_DBG(DEBUG_TRACE_X86EMU) {
                X86EMU_trace_on();
        }
        // run VESA Interrupt
        runInt10();

        if (M.x86.R_AL != 0x4f) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Set Palette Function NOT supported! AL=%x\n",
                     __func__, M.x86.R_AL);
                return -1;
        }

        if (M.x86.R_AH != 0x0) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Set Palette Function Return Code NOT OK! AH=%x\n",
                     __func__, M.x86.R_AH);
                return M.x86.R_AH;
        }
        // read color value from ES:DI
        *color_value = in32le(biosmem + (M.x86.R_ES << 4) + M.x86.R_DI);

        DEBUG_PRINTF_VBE("%s: getting color #%x --> 0x%04x\n", __func__,
                         color_number, *color_value);

        return 0;
}

// VBE Function 15h
u8
vbe_get_ddc_info(vbe_ddc_info_t * ddc_info)
{
        vbe_prepare();
        // call VBE function 15h (DDC Info Function)
        M.x86.R_EAX = 0x4f15;
        M.x86.R_BL = 0x00;      // get DDC Info
        M.x86.R_CX = ddc_info->port_number;
        M.x86.R_ES = 0x0;
        M.x86.R_DI = 0x0;

        // enable trace
        CHECK_DBG(DEBUG_TRACE_X86EMU) {
                X86EMU_trace_on();
        }
        // run VESA Interrupt
        runInt10();

        if (M.x86.R_AL != 0x4f) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Get DDC Info Function NOT supported! AL=%x\n",
                     __func__, M.x86.R_AL);
                return -1;
        }

        if (M.x86.R_AH != 0x0) {
                DEBUG_PRINTF_VBE
                    ("%s: port: %x VBE Get DDC Info Function Return Code NOT OK! AH=%x\n",
                     __func__, ddc_info->port_number, M.x86.R_AH);
                return M.x86.R_AH;
        }
        // BH = approx. time in seconds to transfer one EDID block
        ddc_info->edid_transfer_time = M.x86.R_BH;
        // BL = DDC Level
        ddc_info->ddc_level = M.x86.R_BL;

        vbe_prepare();
        // call VBE function 15h (DDC Info Function)
        M.x86.R_EAX = 0x4f15;
        M.x86.R_BL = 0x01;      // read EDID
        M.x86.R_CX = ddc_info->port_number;
        M.x86.R_DX = 0x0;       // block number
        // ES:DI is address where EDID is stored, we store it at 2000:0000
        M.x86.R_ES = 0x2000;
        M.x86.R_DI = 0x0;

        // enable trace
        CHECK_DBG(DEBUG_TRACE_X86EMU) {
                X86EMU_trace_on();
        }
        // run VESA Interrupt
        runInt10();

        if (M.x86.R_AL != 0x4f) {
                DEBUG_PRINTF_VBE
                    ("%s: VBE Read EDID Function NOT supported! AL=%x\n",
                     __func__, M.x86.R_AL);
                return -1;
        }

        if (M.x86.R_AH != 0x0) {
                DEBUG_PRINTF_VBE
                    ("%s: port: %x VBE Read EDID Function Return Code NOT OK! AH=%x\n",
                     __func__, ddc_info->port_number, M.x86.R_AH);
                return M.x86.R_AH;
        }

        memcpy(ddc_info->edid_block_zero,
               biosmem + (M.x86.R_ES << 4) + M.x86.R_DI,
               sizeof(ddc_info->edid_block_zero));

        return 0;
}

u32
vbe_get_info(u8 argc, char ** argv)
{
        u8 rval;
        u32 i;
        if (argc < 4) {
                printf
                    ("Usage %s <vmem_base> <device_path> <address of screen_info_t>\n",
                     argv[0]);
                int i = 0;
                for (i = 0; i < argc; i++) {
                        printf("argv[%d]: %s\n", i, argv[i]);
                }
                return -1;
        }
        // get a copy of input struct...
        screen_info_input_t input =
            *((screen_info_input_t *) strtoul((char *) argv[4], 0, 16));
        // output is pointer to the address passed as argv[4]
        screen_info_t *output =
            (screen_info_t *) strtoul((char *) argv[4], 0, 16);
        // zero output
        memset(output, 0, sizeof(screen_info_t));

        // argv[1] is address of virtual BIOS mem...
        // argv[2] is the size
        biosmem = (u8 *) strtoul(argv[1], 0, 16);
        biosmem_size = strtoul(argv[2], 0, 16);;
        if (biosmem_size < MIN_REQUIRED_VMEM_SIZE) {
                printf("Error: Not enough virtual memory: %x, required: %x!\n",
                       biosmem_size, MIN_REQUIRED_VMEM_SIZE);
                return -1;
        }
        // argv[3] is the device to open and use...
        if (dev_init((char *) argv[3]) != 0) {
                printf("Error initializing device!\n");
                return -1;
        }
        //setup interrupt handler
        X86EMU_intrFuncs intrFuncs[256];
        for (i = 0; i < 256; i++)
                intrFuncs[i] = handleInterrupt;
        X86EMU_setupIntrFuncs(intrFuncs);
        X86EMU_setupPioFuncs(&my_pio_funcs);
        X86EMU_setupMemFuncs(&my_mem_funcs);

        // set mem_base
        M.mem_base = (long) biosmem;
        M.mem_size = biosmem_size;
        DEBUG_PRINTF_VBE("membase set: %08x, size: %08x\n", (int) M.mem_base,
                         (int) M.mem_size);

        vbe_info_t info;
        rval = vbe_info(&info);
        if (rval != 0)
                return rval;

        DEBUG_PRINTF_VBE("VbeSignature: %s\n", info.signature);
        DEBUG_PRINTF_VBE("VbeVersion: 0x%04x\n", info.version);
        DEBUG_PRINTF_VBE("OemString: %s\n", info.oem_string_ptr);
        DEBUG_PRINTF_VBE("Capabilities:\n");
        DEBUG_PRINTF_VBE("\tDAC: %s\n",
                         (info.capabilities & 0x1) ==
                         0 ? "fixed 6bit" : "switchable 6/8bit");
        DEBUG_PRINTF_VBE("\tVGA: %s\n",
                         (info.capabilities & 0x2) ==
                         0 ? "compatible" : "not compatible");
        DEBUG_PRINTF_VBE("\tRAMDAC: %s\n",
                         (info.capabilities & 0x4) ==
                         0 ? "normal" : "use blank bit in Function 09h");

        // argv[4] may be a pointer with enough space to return screen_info_t
        // as input, it must contain a screen_info_input_t with the following content:
        // byte[0:3] = "DDC\0" (zero-terminated signature header)
        // byte[4:5] = reserved space for the return struct... just in case we ever change
        //             the struct and dont have reserved enough memory (and let's hope the struct
        //             never gets larger than 64KB)
        // byte[6] = monitor port number for DDC requests ("only" one byte... so lets hope we never have more than 255 monitors...
        // byte[7:8] = max. screen width (OF may want to limit this)
        // byte[9] = required color depth in bpp
        if (strncmp((char *) input.signature, "DDC", 4) != 0) {
                printf
                    ("%s: Invalid input signature! expected: %s, is: %s\n",
                     __func__, "DDC", input.signature);
                return -1;
        }
        if (input.size_reserved != sizeof(screen_info_t)) {
                printf
                    ("%s: Size of return struct is wrong, required: %d, available: %d\n",
                     __func__, (int) sizeof(screen_info_t),
                     input.size_reserved);
                return -1;
        }

        vbe_ddc_info_t ddc_info;
        ddc_info.port_number = input.monitor_number;
        vbe_get_ddc_info(&ddc_info);

#if 0
        DEBUG_PRINTF_VBE("DDC: edid_tranfer_time: %d\n",
                         ddc_info.edid_transfer_time);
        DEBUG_PRINTF_VBE("DDC: ddc_level: %x\n", ddc_info.ddc_level);
        DEBUG_PRINTF_VBE("DDC: EDID: \n");
        CHECK_DBG(DEBUG_VBE) {
                dump(ddc_info.edid_block_zero,
                     sizeof(ddc_info.edid_block_zero));
        }
#endif
        if (*((u64 *) ddc_info.edid_block_zero) !=
            (u64) 0x00FFFFFFFFFFFF00) {
                // invalid EDID signature... probably no monitor

                output->display_type = 0x0;
                return 0;
        } else if ((ddc_info.edid_block_zero[20] & 0x80) != 0) {
                // digital display
                output->display_type = 2;
        } else {
                // analog
                output->display_type = 1;
        }
        DEBUG_PRINTF_VBE("DDC: found display type %d\n", output->display_type);
        memcpy(output->edid_block_zero, ddc_info.edid_block_zero,
               sizeof(ddc_info.edid_block_zero));
        i = 0;
        vbe_mode_info_t mode_info;
        vbe_mode_info_t best_mode_info;
        // initialize best_mode to 0
        memset(&best_mode_info, 0, sizeof(best_mode_info));
        while ((mode_info.video_mode = info.video_mode_list[i]) != 0xFFFF) {
                //DEBUG_PRINTF_VBE("%x: Mode: %04x\n", i, mode_info.video_mode);
                vbe_get_mode_info(&mode_info);
#if 0
                DEBUG_PRINTF_VBE("Video Mode 0x%04x available, %s\n",
                                 mode_info.video_mode,
                                 (mode_info.attributes & 0x1) ==
                                 0 ? "not supported" : "supported");
                DEBUG_PRINTF_VBE("\tTTY: %s\n",
                                 (mode_info.attributes & 0x4) ==
                                 0 ? "no" : "yes");
                DEBUG_PRINTF_VBE("\tMode: %s %s\n",
                                 (mode_info.attributes & 0x8) ==
                                 0 ? "monochrome" : "color",
                                 (mode_info.attributes & 0x10) ==
                                 0 ? "text" : "graphics");
                DEBUG_PRINTF_VBE("\tVGA: %s\n",
                                 (mode_info.attributes & 0x20) ==
                                 0 ? "compatible" : "not compatible");
                DEBUG_PRINTF_VBE("\tWindowed Mode: %s\n",
                                 (mode_info.attributes & 0x40) ==
                                 0 ? "yes" : "no");
                DEBUG_PRINTF_VBE("\tFramebuffer: %s\n",
                                 (mode_info.attributes & 0x80) ==
                                 0 ? "no" : "yes");
                DEBUG_PRINTF_VBE("\tResolution: %dx%d\n",
                                 mode_info.x_resolution,
                                 mode_info.y_resolution);
                DEBUG_PRINTF_VBE("\tChar Size: %dx%d\n",
                                 mode_info.x_charsize, mode_info.y_charsize);
                DEBUG_PRINTF_VBE("\tColor Depth: %dbpp\n",
                                 mode_info.bits_per_pixel);
                DEBUG_PRINTF_VBE("\tMemory Model: 0x%x\n",
                                 mode_info.memory_model);
                DEBUG_PRINTF_VBE("\tFramebuffer Offset: %08x\n",
                                 mode_info.framebuffer_address);
#endif
                if ((mode_info.bits_per_pixel == input.color_depth)
                    && (mode_info.x_resolution <= input.max_screen_width)
                    && ((mode_info.attributes & 0x80) != 0)     // framebuffer mode
                    && ((mode_info.attributes & 0x10) != 0)     // graphics
                    && ((mode_info.attributes & 0x8) != 0)      // color
                    && (mode_info.x_resolution > best_mode_info.x_resolution))  // better than previous best_mode
                {
                        // yiiiihaah... we found a new best mode
                        memcpy(&best_mode_info, &mode_info, sizeof(mode_info));
                }
                i++;
        }

        if (best_mode_info.video_mode != 0) {
                DEBUG_PRINTF_VBE
                    ("Best Video Mode found: 0x%x, %dx%d, %dbpp, framebuffer_address: 0x%x\n",
                     best_mode_info.video_mode,
                     best_mode_info.x_resolution,
                     best_mode_info.y_resolution,
                     best_mode_info.bits_per_pixel,
                     best_mode_info.framebuffer_address);

                //printf("Mode Info Dump:");
                //dump(best_mode_info.mode_info_block, 64);

                // set the video mode
                vbe_set_mode(&best_mode_info);

                if ((info.capabilities & 0x1) != 0) {
                        // switch to 8 bit palette format
                        vbe_set_palette_format(8);
                }
                // setup a palette:
                // - first 216 colors are mixed colors for each component in 6 steps
                //   (6*6*6=216)
                // - then 10 shades of the three primary colors
                // - then 10 shades of grey
                // -------
                // = 256 colors
                //
                // - finally black is color 0 and white color FF (because SLOF expects it
                //   this way...)
                // this resembles the palette that the kernel/X Server seems to expect...

                u8 mixed_color_values[6] =
                    { 0xFF, 0xDA, 0xB3, 0x87, 0x54, 0x00 };
                u8 primary_color_values[10] =
                    { 0xF3, 0xE7, 0xCD, 0xC0, 0xA5, 0x96, 0x77, 0x66, 0x3F,
                        0x27
                };
                u8 mc_size = sizeof(mixed_color_values);
                u8 prim_size = sizeof(primary_color_values);

                u8 curr_color_index;
                u32 curr_color;

                u8 r, g, b;
                // 216 mixed colors
                for (r = 0; r < mc_size; r++) {
                        for (g = 0; g < mc_size; g++) {
                                for (b = 0; b < mc_size; b++) {
                                        curr_color_index =
                                            (r * mc_size * mc_size) +
                                            (g * mc_size) + b;
                                        curr_color = 0;
                                        curr_color |= ((u32) mixed_color_values[r]) << 16;      //red value
                                        curr_color |= ((u32) mixed_color_values[g]) << 8;       //green value
                                        curr_color |= (u32) mixed_color_values[b];      //blue value
                                        vbe_set_color(curr_color_index,
                                                      curr_color);
                                }
                        }
                }

                // 10 shades of each primary color
                // red
                for (r = 0; r < prim_size; r++) {
                        curr_color_index = mc_size * mc_size * mc_size + r;
                        curr_color = ((u32) primary_color_values[r]) << 16;
                        vbe_set_color(curr_color_index, curr_color);
                }
                //green
                for (g = 0; g < prim_size; g++) {
                        curr_color_index =
                            mc_size * mc_size * mc_size + prim_size + g;
                        curr_color = ((u32) primary_color_values[g]) << 8;
                        vbe_set_color(curr_color_index, curr_color);
                }
                //blue
                for (b = 0; b < prim_size; b++) {
                        curr_color_index =
                            mc_size * mc_size * mc_size + prim_size * 2 + b;
                        curr_color = (u32) primary_color_values[b];
                        vbe_set_color(curr_color_index, curr_color);
                }
                // 10 shades of grey
                for (i = 0; i < prim_size; i++) {
                        curr_color_index =
                            mc_size * mc_size * mc_size + prim_size * 3 + i;
                        curr_color = 0;
                        curr_color |= ((u32) primary_color_values[i]) << 16;    //red
                        curr_color |= ((u32) primary_color_values[i]) << 8;     //green
                        curr_color |= ((u32) primary_color_values[i]);  //blue
                        vbe_set_color(curr_color_index, curr_color);
                }

                // SLOF is using color 0x0 (black) and 0xFF (white) to draw to the screen...
                vbe_set_color(0x00, 0x00000000);
                vbe_set_color(0xFF, 0x00FFFFFF);

                output->screen_width = best_mode_info.x_resolution;
                output->screen_height = best_mode_info.y_resolution;
                output->screen_linebytes = best_mode_info.linebytes;
                output->color_depth = best_mode_info.bits_per_pixel;
                output->framebuffer_address =
                    best_mode_info.framebuffer_address;
        } else {
                printf("%s: No suitable video mode found!\n", __func__);
                //unset display_type...
                output->display_type = 0;
        }
        return 0;
}