scr_ecospcsvga.c

eCos操作系统源码

//=============================================================================
//
//      scr_ecospcsvga.c
//
//      eCos support for a PC display using SVGA/VESA
//
//=============================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//=============================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):    bartv
// Date:         2002-04-19
// Purpose:      Implement a screen driver for PC's with a VESA video BIOS
//
//    PC graphics cards are problematical. Many graphic cards are still more
//    or less compatible with ancient VGA hardware, but this provides access
//    only to rather low resolutions. There is no other hardware compatibility,
//    and many different graphics card all needing their own driver.
//
//    Each graphics card comes with a video BIOS @ 0x000C0000, which can be
//    invoked via int 0x10 to do useful operations like querying the
//    available video modes and setting the desired one. However the video
//    BIOS can normally only be called in x86 real mode, not protected mode,
//    Currently eCos only runs in protected mode, and has no support for
//    briefly switching back into real mode.
//
//    Current VESA VBE2 compliant graphics cards do offer some protected
//    mode entry points, but not enough to perform mode switches etc.
//    VBE3 is supposed to provide additional support for protected mode
//    applications, but does not appear to be widely implemented yet.
//
//    So for now the only solution is to perform the mode switching
//    during bootstrap, and specifically inside RedBoot. This is controlled
//    by an option in the RedBoot configuration, which has the side
//    effect of disabling RedBoot's own use of the screen and keyboard.
//    SVGA graphics modes are not completely standardized, so it is the
//    user's responsibility to pick a suitable mode.
//
//    Because RedBoot is a separate application, it is not guaranteed
//    that the appropriate mode switch has actually occurred by the
//    time this code runs. Therefore RedBoot also places the main SVGA
//    info block at location 0x000A0000, normally a window into video
//    memory, since that memory is not being used for anything else
//    right now. Similarly the mode info block for the current mode
//    is placed @ 0x000A0200, and to make it easier to find out what
//    modes are available on the current hardware and allow RedBoot to
//    be reconfigured appropriately, all the mode info blocks are
//    stored @ 0x000A0400 at 256-byte boundaries. The main info block
//    can be used to find out which modes are actually available.
//
//####DESCRIPTIONEND####
//=============================================================================


#include <pkgconf/system.h>
#include <pkgconf/microwindows.h>
#include <cyg/infra/cyg_ass.h>
#include <cyg/infra/diag.h>
#include <microwin/device.h>

#define VTSWITCH 0
#include "fb.h"
#include "genfont.h"
#include "genmem.h"

// ----------------------------------------------------------------------------
// Information about the current mode and all available video modes,
// should have been provided by RedBoot.
struct VBESVGAInfoBlock {
    unsigned char   signature[4];      /* VESA */
    unsigned short  version;
    char*           oem_string_ptr;
    unsigned char   capabilities[4];
    unsigned short* video_mode_ptr;
    unsigned short  total_memory;
    unsigned short  oem_software_rev;
    char*           oem_vendor_name_ptr;
    char*           oem_product_name_ptr;
    char*           oem_product_rev_ptr;
    /* Reserved data here */
} __attribute__((packed));

struct VBEModeInfoBlock {
    unsigned short  mode_attributes;
    unsigned char   win_a_atributes;
    unsigned char   win_b_attributes;
    unsigned short  win_granularity;
    unsigned short  win_size;
    unsigned short  win_a_segment;
    unsigned short  win_b_segment;
    unsigned int    win_func_ptr;
    unsigned short  bytes_per_scanline;
    unsigned short  x_resolution;
    unsigned short  y_resolution;
    unsigned char   x_char_size;
    unsigned char   y_char_size;
    unsigned char   number_of_planes;
    unsigned char   bits_per_pixel;
    unsigned char   number_of_banks;
    unsigned char   memory_model;
    unsigned char   bank_size;
    unsigned char   number_of_image_pages;
    unsigned char   reserved;
    unsigned char   red_mask_size;
    unsigned char   red_field_position;
    unsigned char   green_mask_size;
    unsigned char   green_field_position;
    unsigned char   blue_mask_size;
    unsigned char   blue_field_position;
    unsigned char   reserved_mask_size;
    unsigned char   reserved_field_position;
    unsigned char   direct_color_mode_info;
    void*           physical_base_ptr;
    unsigned int    offscreen_memory_offset;
    unsigned short  offscreen_memory_size;
} __attribute__((packed));

#if defined(CYGDBG_MICROWINDOWS_PCSVGA_VERBOSE)
static void*
segoff_to_phys(void* addr)
{
    int x       = (int) addr;
    int segment = (x >> 12) & 0x0FFFF0;
    int offset  = x & 0x0FFFF;
    return (void*) (segment | offset);
}
#endif

// ----------------------------------------------------------------------------
static PSD  ecos_pcsvga_open(PSD);
static void ecos_pcsvga_close(PSD);
static void ecos_pcsvga_setportrait(PSD, int);
static void ecos_pcsvga_setpalette(PSD, int, int, MWPALENTRY*);
static void ecos_pcsvga_getscreeninfo(PSD , PMWSCREENINFO);

SCREENDEVICE scrdev = {
    xres:               0,
    yres:               0,
    xvirtres:           0,
    yvirtres:           0,
    planes:             1,
    linelen:            0,
    size:               0,
#if defined(CYGIMP_MICROWINDOWS_PCSVGA32)
    bpp:                32,
    ncolors:            1 << 24,
    pixtype:            MWPF_TRUECOLOR0888,
#elif defined(CYGIMP_MICROWINDOWS_PCSVGA16)
    bpp:                16,
    ncolors:            1 << 16,
    pixtype:            MWPF_TRUECOLOR565,
#else
# error Unsupported video mode.    
#endif    
    flags:              PSF_SCREEN | PSF_HAVEBLIT,
    addr:               0,

    Open:               &ecos_pcsvga_open,
    Close:              &ecos_pcsvga_close,
    GetScreenInfo:      &ecos_pcsvga_getscreeninfo,
    SetPalette:         &ecos_pcsvga_setpalette,
    DrawPixel:          NULL,
    ReadPixel:          NULL,
    DrawHorzLine:       NULL,
    DrawVertLine:       NULL,
    FillRect:           NULL,
    builtin_fonts:      gen_fonts,
    Blit:               NULL,
    PreSelect:          NULL,
    DrawArea:           NULL,
    SetIOPermissions:   NULL,
    AllocateMemGC:      &gen_allocatememgc,
    MapMemGC:           &fb_mapmemgc,
    FreeMemGC:          &gen_freememgc,
    StretchBlit:        NULL,
    SetPortrait:        &ecos_pcsvga_setportrait,
    portrait:           MWPORTRAIT_NONE,
    orgsubdriver:       NULL
};

static PSD
ecos_pcsvga_open(PSD psd)
{
    struct VBESVGAInfoBlock*    vesa_info_block;
    struct VBEModeInfoBlock*    vesa_current_mode;
    
    // Detect repeated invocations. The information in the video
    // memory will be blown away after the first call, so can
    // only be consulted once.
    static int  opened  = 0;
    static PSD  result  = NULL;
    if (opened) {