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/* ----------------------------------------------------------------------- *
 *
 *   Copyright 1999-2008 H. Peter Anvin - All Rights Reserved
 *
 *   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 AUTHORS OR COPYRIGHT
 *   HOLDERS 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.
 *
 * ----------------------------------------------------------------------- */

/*
 * initvesa.c
 *
 * Query the VESA BIOS and select a 640x480x32 mode with local mapping
 * support, if one exists.
 */

#include <inttypes.h>
#include <com32.h>
#include <stdlib.h>
#include <string.h>
#include <sys/fpu.h>
#include <syslinux/video.h>
#include "vesa.h"
#include "video.h"
#include "fill.h"
#include "debug.h"

struct vesa_info __vesa_info;

struct vesa_char *__vesacon_text_display;

int __vesacon_font_height;
int __vesacon_text_rows;
int __vesacon_text_cols;
enum vesa_pixel_format __vesacon_pixel_format = PXF_NONE;
unsigned int __vesacon_bytes_per_pixel;
uint8_t __vesacon_graphics_font[FONT_MAX_CHARS][FONT_MAX_HEIGHT];

uint32_t *__vesacon_background, *__vesacon_shadowfb;

static void unpack_font(uint8_t * dst, uint8_t * src, int height)
{
    int i;

    for (i = 0; i < FONT_MAX_CHARS; i++) {
	memcpy(dst, src, height);
	memset(dst + height, 0, FONT_MAX_HEIGHT - height);

	dst += FONT_MAX_HEIGHT;
	src += height;
    }
}

static int __constfunc is_power_of_2(unsigned int x)
{
    return x && !(x & (x - 1));
}

static int vesacon_paged_mode_ok(const struct vesa_mode_info *mi)
{
    int i;

    if (!is_power_of_2(mi->win_size) ||
	!is_power_of_2(mi->win_grain) || mi->win_grain > mi->win_size)
	return 0;		/* Impossible... */

    for (i = 0; i < 2; i++) {
	if ((mi->win_attr[i] & 0x05) == 0x05 && mi->win_seg[i])
	    return 1;		/* Usable window */
    }

    return 0;			/* Nope... */
}

static int vesacon_set_mode(int x, int y)
{
    com32sys_t rm;
    uint8_t *rom_font;
    uint16_t mode, bestmode, *mode_ptr;
    struct vesa_general_info *gi;
    struct vesa_mode_info *mi;
    enum vesa_pixel_format pxf, bestpxf;

    /* Free any existing data structures */
    if (__vesacon_background) {
	free(__vesacon_background);
	__vesacon_background = NULL;
    }
    if (__vesacon_shadowfb) {
	free(__vesacon_shadowfb);
	__vesacon_shadowfb = NULL;
    }

    /* Allocate space in the bounce buffer for these structures */
    gi = &((struct vesa_info *)__com32.cs_bounce)->gi;
    mi = &((struct vesa_info *)__com32.cs_bounce)->mi;

    debug("Hello, World!\r\n");

    memset(&rm, 0, sizeof rm);
    memset(gi, 0, sizeof *gi);

    gi->signature = VBE2_MAGIC;	/* Get VBE2 extended data */
    rm.eax.w[0] = 0x4F00;	/* Get SVGA general information */
    rm.edi.w[0] = OFFS(gi);
    rm.es = SEG(gi);
    __intcall(0x10, &rm, &rm);

    if (rm.eax.w[0] != 0x004F)
	return 1;		/* Function call failed */
    if (gi->signature != VESA_MAGIC)
	return 2;		/* No magic */
    if (gi->version < 0x0102)
	return 3;		/* VESA 1.2+ required */

    /* Copy general info */
    memcpy(&__vesa_info.gi, gi, sizeof *gi);

    /* Search for the proper mode with a suitable color and memory model... */

    mode_ptr = GET_PTR(gi->video_mode_ptr);
    bestmode = 0;
    bestpxf = PXF_NONE;

    while ((mode = *mode_ptr++) != 0xFFFF) {
	mode &= 0x1FF;		/* The rest are attributes of sorts */

	debug("Found mode: 0x%04x\r\n", mode);

	memset(mi, 0, sizeof *mi);
	rm.eax.w[0] = 0x4F01;	/* Get SVGA mode information */
	rm.ecx.w[0] = mode;
	rm.edi.w[0] = OFFS(mi);
	rm.es = SEG(mi);
	__intcall(0x10, &rm, &rm);

	/* Must be a supported mode */
	if (rm.eax.w[0] != 0x004f)
	    continue;

	debug
	    ("mode_attr 0x%04x, h_res = %4d, v_res = %4d, bpp = %2d, layout = %d (%d,%d,%d)\r\n",
	     mi->mode_attr, mi->h_res, mi->v_res, mi->bpp, mi->memory_layout,
	     mi->rpos, mi->gpos, mi->bpos);

	/* Must be an LFB color graphics mode supported by the hardware.

	   The bits tested are:
	   4 - graphics mode
	   3 - color mode
	   1 - mode information available (mandatory in VBE 1.2+)
	   0 - mode supported by hardware
	 */
	if ((mi->mode_attr & 0x001b) != 0x001b)
	    continue;

	/* Must be the chosen size */
	if (mi->h_res != x || mi->v_res != y)
	    continue;

	/* We don't support multibank (interlaced memory) modes */
	/*
	 *  Note: The Bochs VESA BIOS (vbe.c 1.58 2006/08/19) violates the
	 * specification which states that banks == 1 for unbanked modes;
	 * fortunately it does report bank_size == 0 for those.
	 */
	if (mi->banks > 1 && mi->bank_size) {
	    debug("bad: banks = %d, banksize = %d, pages = %d\r\n",
		  mi->banks, mi->bank_size, mi->image_pages);
	    continue;
	}

	/* Must be either a flat-framebuffer mode, or be an acceptable
	   paged mode */
	if (!(mi->mode_attr & 0x0080) && !vesacon_paged_mode_ok(mi)) {
	    debug("bad: invalid paged mode\r\n");
	    continue;
	}

	/* Must either be a packed-pixel mode or a direct color mode
	   (depending on VESA version ); must be a supported pixel format */
	pxf = PXF_NONE;		/* Not usable */

	if (mi->bpp == 32 &&
	    (mi->memory_layout == 4 ||
	     (mi->memory_layout == 6 && mi->rpos == 16 && mi->gpos == 8 &&
	      mi->bpos == 0)))
	    pxf = PXF_BGRA32;
	else if (mi->bpp == 24 &&
		 (mi->memory_layout == 4 ||
		  (mi->memory_layout == 6 && mi->rpos == 16 && mi->gpos == 8 &&
		   mi->bpos == 0)))
	    pxf = PXF_BGR24;
	else if (mi->bpp == 16 &&
		 (mi->memory_layout == 4 ||
		  (mi->memory_layout == 6 && mi->rpos == 11 && mi->gpos == 5 &&
		   mi->bpos == 0)))
	    pxf = PXF_LE_RGB16_565;
	else if (mi->bpp == 15 &&
		 (mi->memory_layout == 4 ||
		  (mi->memory_layout == 6 && mi->rpos == 10 && mi->gpos == 5 &&
		   mi->bpos == 0)))
	    pxf = PXF_LE_RGB15_555;

	if (pxf < bestpxf) {
	    debug("Best mode so far, pxf = %d\r\n", pxf);

	    /* Best mode so far... */
	    bestmode = mode;
	    bestpxf = pxf;

	    /* Copy mode info */
	    memcpy(&__vesa_info.mi, mi, sizeof *mi);
	}
    }

    if (bestpxf == PXF_NONE)
	return 4;		/* No mode found */

    mi = &__vesa_info.mi;
    mode = bestmode;
    __vesacon_bytes_per_pixel = (mi->bpp + 7) >> 3;
    __vesacon_format_pixels = __vesacon_format_pixels_list[bestpxf];

    /* Download the SYSLINUX- or BIOS-provided font */
    __vesacon_font_height = syslinux_font_query(&rom_font);
    if (!__vesacon_font_height) {
	/* Get BIOS 8x16 font */

	rm.eax.w[0] = 0x1130;	/* Get Font Information */
	rm.ebx.w[0] = 0x0600;	/* Get 8x16 ROM font */
	__intcall(0x10, &rm, &rm);
	rom_font = MK_PTR(rm.es, rm.ebp.w[0]);
	__vesacon_font_height = 16;
    }
    unpack_font((uint8_t *) __vesacon_graphics_font, rom_font,
		__vesacon_font_height);

    /* Now set video mode */
    rm.eax.w[0] = 0x4F02;	/* Set SVGA video mode */
    if (mi->mode_attr & 0x0080)
	mode |= 0x4000;		/* Request linear framebuffer if supported */
    rm.ebx.w[0] = mode;
    __intcall(0x10, &rm, &rm);
    if (rm.eax.w[0] != 0x004F)
	return 9;		/* Failed to set mode */

    __vesacon_background = calloc(mi->h_res*mi->v_res, 4);
    __vesacon_shadowfb = calloc(mi->h_res*mi->v_res, 4);

    __vesacon_init_copy_to_screen();

    /* Tell syslinux we changed video mode */
    /* In theory this should be:

       flags = (mi->mode_attr & 4) ? 0x0007 : 0x000f;

       However, that would assume all systems that claim to handle text
       output in VESA modes actually do that... */
    syslinux_report_video_mode(0x000f, mi->h_res, mi->v_res);

    __vesacon_pixel_format = bestpxf;

    return 0;
}

static int init_text_display(void)
{
    size_t nchars;
    struct vesa_char *ptr;
    struct vesa_char def_char = {
	.ch = ' ',
	.attr = 0,
    };

    if (__vesacon_text_display)
	free(__vesacon_text_display);

    __vesacon_text_cols = TEXT_PIXEL_COLS / FONT_WIDTH;
    __vesacon_text_rows = TEXT_PIXEL_ROWS / __vesacon_font_height;
    nchars = (__vesacon_text_cols+2) * (__vesacon_text_rows+2);

    __vesacon_text_display = ptr = malloc(nchars * sizeof(struct vesa_char));

    if (!ptr)
	return -1;

    vesacon_fill(ptr, def_char, nchars);
    __vesacon_init_cursor(__vesacon_font_height);

    return 0;
}

int __vesacon_init(int x, int y)
{
    int rv;

    /* We need the FPU for graphics, at least libpng et al will need it... */
    if (x86_init_fpu())
	return 10;

    rv = vesacon_set_mode(x, y);
    if (rv) {
	/* Try to see if we can just patch the BIOS... */
	if (__vesacon_i915resolution(x, y))
	    return rv;
	if (vesacon_set_mode(x, y))
	    return rv;
    }

    init_text_display();

    debug("Mode set, now drawing at %#p\r\n", __vesa_info.mi.lfb_ptr);

    __vesacon_init_background();

    debug("Ready!\r\n");
    return 0;
}