arch/i386-pc/kernel/kernel_debug.c

   1 /*
   2     Copyright © 1995-2018, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <bootconsole.h>
   7 #include <string.h>
   8
   9 #include "kernel_base.h"
  10 #include "kernel_debug.h"
  11 #include "kernel_intern.h"
  12
  13 __attribute__((section(".data"))) static unsigned int debug_y_resolution = 0;
  14 __attribute__((section(".data"))) static void *debug_framebuffer = NULL;
  15
  16 int krnPutC(int c, struct KernelBase *KernelBase)
  17 {
  18     unsigned long flags;
  19
  20     __save_flags(flags);
  21
  22     /*
  23      * Don't use Disable/Enable, because we want the interrupt enabled flag
  24      * to stay the same as it was before the Disable() call
  25      */
  26     __cli();
  27
  28     /*
  29      * If we got 0x03, this means graphics driver wants to take over the screen.
  30      * If VESA hack is activated, it will use only upper half of the screen
  31      * because y resolution was adjusted.
  32      * In our turn, we need to switch over to lower half.
  33      * VESA hack is supported only on graphical console of course. And do not
  34      * expect it to work with native mode video driver. :)
  35      */
  36     if ((c == 0x03) && (scr_Type == SCR_GFX) && debug_framebuffer)
  37     {
  38         /* Reinitialize boot console with decreased height */
  39         scr_FrameBuffer = debug_framebuffer;
  40         fb_Resize(debug_y_resolution);
  41     }
  42     else
  43         con_Putc(c);
  44
  45     /*
  46      * Interrupt flag is stored in flags - if it was enabled before,
  47      * it will be re-enabled when the flags are restored
  48      */
  49     __restore_flags(flags);
  50
  51     return 1;
  52 }
  53
  54 void vesahack_Init(char *cmdline, struct vbe_mode *vmode)
  55 {
  56     if (cmdline && vmode && vmode->phys_base && strstr(cmdline, "vesahack"))
  57     {
  58         bug("[Kernel] VESA debugging hack activated\n");
  59
  60         /*
  61          * VESA hack.
  62          * It divides screen height by 2 and increments framebuffer pointer.
  63          * This allows VESA driver to use only upper half of the screen, while
  64          * lower half will still be used for debug output.
  65          */
  66         vmode->y_resolution >>= 1;
  67
  68         debug_y_resolution = vmode->y_resolution;
  69         debug_framebuffer  = (void *)(unsigned long)vmode->phys_base + vmode->y_resolution * vmode->bytes_per_scanline;
  70     }
  71 }