video-vesa.c

Go to the documentation of this file.

/* -*- linux-c -*- ------------------------------------------------------- *
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 *   Copyright 2009 Intel Corporation; author H. Peter Anvin
 *
 *   This file is part of the Linux kernel, and is made available under
 *   the terms of the GNU General Public License version 2.
 *
 * ----------------------------------------------------------------------- */

/*
 * VESA text modes
 */

#include "boot.h"
#include "video.h"
#include "vesa.h"

/* VESA information */
static struct vesa_general_info vginfo;
static struct vesa_mode_info vminfo;

static __videocard video_vesa;

#ifndef _WAKEUP
static void vesa_store_mode_params_graphics(void);
#else /* _WAKEUP */
static inline void vesa_store_mode_params_graphics(void) {}
#endif /* _WAKEUP */

static int vesa_probe(void)
{
    struct biosregs ireg, oreg;
    u16 mode;
    addr_t mode_ptr;
    struct mode_info *mi;
    int nmodes = 0;

    video_vesa.modes = GET_HEAP(struct mode_info, 0);

    initregs(&ireg);
    ireg.ax = 0x4f00;
    ireg.di = (size_t)&vginfo;
    intcall(0x10, &ireg, &oreg);

    if (oreg.ax != 0x004f ||
        vginfo.signature != VESA_MAGIC ||
        vginfo.version < 0x0102)
        return 0;   /* Not present */

    set_fs(vginfo.video_mode_ptr.seg);
    mode_ptr = vginfo.video_mode_ptr.off;

    while ((mode = rdfs16(mode_ptr)) != 0xffff) {
        mode_ptr += 2;

        if (!heap_free(sizeof(struct mode_info)))
            break;  /* Heap full, can't save mode info */

        if (mode & ~0x1ff)
            continue;

        memset(&vminfo, 0, sizeof vminfo); /* Just in case... */

        ireg.ax = 0x4f01;
        ireg.cx = mode;
        ireg.di = (size_t)&vminfo;
        intcall(0x10, &ireg, &oreg);

        if (oreg.ax != 0x004f)
            continue;

        if ((vminfo.mode_attr & 0x15) == 0x05) {
            /* Text Mode, TTY BIOS supported,
               supported by hardware */
            mi = GET_HEAP(struct mode_info, 1);
            mi->mode  = mode + VIDEO_FIRST_VESA;
            mi->depth = 0; /* text */
            mi->x     = vminfo.h_res;
            mi->y     = vminfo.v_res;
            nmodes++;
        } else if ((vminfo.mode_attr & 0x99) == 0x99 &&
               (vminfo.memory_layout == 4 ||
                vminfo.memory_layout == 6) &&
               vminfo.memory_planes == 1) {
#ifdef CONFIG_FB_BOOT_VESA_SUPPORT
            /* Graphics mode, color, linear frame buffer
               supported.  Only register the mode if
               if framebuffer is configured, however,
               otherwise the user will be left without a screen. */
            mi = GET_HEAP(struct mode_info, 1);
            mi->mode = mode + VIDEO_FIRST_VESA;
            mi->depth = vminfo.bpp;
            mi->x = vminfo.h_res;
            mi->y = vminfo.v_res;
            nmodes++;
#endif
        }
    }

    return nmodes;
}

static int vesa_set_mode(struct mode_info *mode)
{
    struct biosregs ireg, oreg;
    int is_graphic;
    u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;

    memset(&vminfo, 0, sizeof vminfo); /* Just in case... */

    initregs(&ireg);
    ireg.ax = 0x4f01;
    ireg.cx = vesa_mode;
    ireg.di = (size_t)&vminfo;
    intcall(0x10, &ireg, &oreg);

    if (oreg.ax != 0x004f)
        return -1;

    if ((vminfo.mode_attr & 0x15) == 0x05) {
        /* It's a supported text mode */
        is_graphic = 0;
#ifdef CONFIG_FB_BOOT_VESA_SUPPORT
    } else if ((vminfo.mode_attr & 0x99) == 0x99) {
        /* It's a graphics mode with linear frame buffer */
        is_graphic = 1;
        vesa_mode |= 0x4000; /* Request linear frame buffer */
#endif
    } else {
        return -1;  /* Invalid mode */
    }


    initregs(&ireg);
    ireg.ax = 0x4f02;
    ireg.bx = vesa_mode;
    intcall(0x10, &ireg, &oreg);

    if (oreg.ax != 0x004f)
        return -1;

    graphic_mode = is_graphic;
    if (!is_graphic) {
        /* Text mode */
        force_x = mode->x;
        force_y = mode->y;
        do_restore = 1;
    } else {
        /* Graphics mode */
        vesa_store_mode_params_graphics();
    }

    return 0;
}


#ifndef _WAKEUP

/* Switch DAC to 8-bit mode */
static void vesa_dac_set_8bits(void)
{
    struct biosregs ireg, oreg;
    u8 dac_size = 6;

    /* If possible, switch the DAC to 8-bit mode */
    if (vginfo.capabilities & 1) {
        initregs(&ireg);
        ireg.ax = 0x4f08;
        ireg.bh = 0x08;
        intcall(0x10, &ireg, &oreg);
        if (oreg.ax == 0x004f)
            dac_size = oreg.bh;
    }

    /* Set the color sizes to the DAC size, and offsets to 0 */
    boot_params.screen_info.red_size   = dac_size;
    boot_params.screen_info.green_size = dac_size;
    boot_params.screen_info.blue_size  = dac_size;
    boot_params.screen_info.rsvd_size  = dac_size;

    boot_params.screen_info.red_pos    = 0;
    boot_params.screen_info.green_pos  = 0;
    boot_params.screen_info.blue_pos   = 0;
    boot_params.screen_info.rsvd_pos   = 0;
}

/* Save the VESA protected mode info */
static void vesa_store_pm_info(void)
{
    struct biosregs ireg, oreg;

    initregs(&ireg);
    ireg.ax = 0x4f0a;
    intcall(0x10, &ireg, &oreg);

    if (oreg.ax != 0x004f)
        return;

    boot_params.screen_info.vesapm_seg = oreg.es;
    boot_params.screen_info.vesapm_off = oreg.di;
}

/*
 * Save video mode parameters for graphics mode
 */
static void vesa_store_mode_params_graphics(void)
{
    /* Tell the kernel we're in VESA graphics mode */
    boot_params.screen_info.orig_video_isVGA = VIDEO_TYPE_VLFB;

    /* Mode parameters */
    boot_params.screen_info.vesa_attributes = vminfo.mode_attr;
    boot_params.screen_info.lfb_linelength = vminfo.logical_scan;
    boot_params.screen_info.lfb_width = vminfo.h_res;
    boot_params.screen_info.lfb_height = vminfo.v_res;
    boot_params.screen_info.lfb_depth = vminfo.bpp;
    boot_params.screen_info.pages = vminfo.image_planes;
    boot_params.screen_info.lfb_base = vminfo.lfb_ptr;
    memcpy(&boot_params.screen_info.red_size,
           &vminfo.rmask, 8);

    /* General parameters */
    boot_params.screen_info.lfb_size = vginfo.total_memory;

    if (vminfo.bpp <= 8)
        vesa_dac_set_8bits();

    vesa_store_pm_info();
}

/*
 * Save EDID information for the kernel; this is invoked, separately,
 * after mode-setting.
 */
void vesa_store_edid(void)
{
#ifdef CONFIG_FIRMWARE_EDID
    struct biosregs ireg, oreg;

    /* Apparently used as a nonsense token... */
    memset(&boot_params.edid_info, 0x13, sizeof boot_params.edid_info);

    if (vginfo.version < 0x0200)
        return;     /* EDID requires VBE 2.0+ */

    initregs(&ireg);
    ireg.ax = 0x4f15;       /* VBE DDC */
    /* ireg.bx = 0x0000; */     /* Report DDC capabilities */
    /* ireg.cx = 0; */      /* Controller 0 */
    ireg.es = 0;            /* ES:DI must be 0 by spec */
    intcall(0x10, &ireg, &oreg);

    if (oreg.ax != 0x004f)
        return;     /* No EDID */

    /* BH = time in seconds to transfer EDD information */
    /* BL = DDC level supported */

    ireg.ax = 0x4f15;       /* VBE DDC */
    ireg.bx = 0x0001;       /* Read EDID */
    /* ireg.cx = 0; */      /* Controller 0 */
    /* ireg.dx = 0; */      /* EDID block number */
    ireg.es = ds();
    ireg.di =(size_t)&boot_params.edid_info; /* (ES:)Pointer to block */
    intcall(0x10, &ireg, &oreg);
#endif /* CONFIG_FIRMWARE_EDID */
}

#endif /* not _WAKEUP */

static __videocard video_vesa =
{
    .card_name  = "VESA",
    .probe      = vesa_probe,
    .set_mode   = vesa_set_mode,
    .xmode_first    = VIDEO_FIRST_VESA,
    .xmode_n    = 0x200,
};