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arch/x86/boot/video-vesa.c

arch/x86/boot/video-vesa.c (280 lines, 6833 bytes)
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/* -*- 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,
};