hal/halx86/bios32.c

   1 /*
   2  * COPYRIGHT:       See COPYING in the top level directory
   3  * PROJECT:         ReactOS kernel
   4  * FILE:            ntoskrnl/hal/pci
   5  * PURPOSE:         Interfaces to BIOS32 interface
   6  * PROGRAMMER:      David Welch (welch@mcmail.com)
   7  * UPDATE HISTORY:
   8  *               05/06/98: Created
   9  */
  10
  11 /*
  12  * NOTES: Sections copied from the Linux pci support
  13  */
  14
  15 /* INCLUDES ***************************************************************/
  16
  17 #include <ddk/ntddk.h>
  18 #include <internal/mm.h>
  19 #include <internal/i386/segment.h>
  20
  21
  22 /* TYPES ******************************************************************/
  23
  24 typedef struct
  25 {
  26    /*
  27     * "_32_" if present
  28     */
  29    unsigned int signature;
  30
  31    /*
  32     * Entry point (physical address)
  33     */
  34    unsigned long int entry;
  35
  36    /*
  37     * Revision level
  38     */
  39    unsigned char revision;
  40
  41    /*
  42     * Length in paragraphs
  43     */
  44    unsigned char length;
  45
  46    /*
  47     * Checksum (so all bytes add up to zero)
  48     */
  49    unsigned char checksum;
  50
  51    unsigned char reserved[5];
  52 } bios32;
  53
  54 BOOLEAN bios32_detected = FALSE;
  55
  56 static struct
  57 {
  58    unsigned long address;
  59    unsigned short segment;
  60 } bios32_indirect = {0,KERNEL_CS};
  61
  62 /* FUNCTIONS **************************************************************/
  63
  64 #define BIOS32_SIGNATURE (('_' << 0)+('3'<<8)+('2'<<16)+('_'<<24))
  65
  66 #if 0
  67 BOOL static checksum(bios32* service_entry)
  68 /*
  69  * FUNCTION: Checks the checksum of a bios32 service entry
  70  * ARGUMENTS:
  71  *         service_entry = Pointer to the service entry
  72  * RETURNS: True if the sum of the bytes in the entry was zero
  73  *          False otherwise
  74  */
  75 {
  76    unsigned char* p = (unsigned char *)service_entry;
  77    int i;
  78    unsigned char sum=0;
  79
  80    for (i=0; i<(service_entry->length*16); i++)
  81      {
  82         sum=sum+p[i];
  83      }
  84 //   DbgPrint("sum = %d\n",sum);
  85    if (sum==0)
  86      {
  87         return(TRUE);
  88      }
  89    return(FALSE);
  90 }
  91 #endif
  92
  93 BOOLEAN Hal_bios32_is_service_present(ULONG service)
  94 {
  95    unsigned char return_code;
  96    unsigned int address;
  97    unsigned int length;
  98    unsigned int entry;
  99
 100    __asm__("lcall *(%%edi)"
 101            : "=a" (return_code),
 102              "=b" (address),
 103              "=c" (length),
 104              "=d" (entry)
 105            : "0" (service),
 106              "1" (0),
 107              "D" (&bios32_indirect));
 108    if (return_code==0)
 109      {
 110         return(address+entry);
 111      }
 112    return(0);
 113 }
 114
 115 VOID Hal_bios32_probe()
 116 /*
 117  * FUNCTION: Probes for an BIOS32 extension
 118  * RETURNS: True if detected
 119  */
 120 {
 121    DbgPrint ("Hal_bios32_probe()\n");
 122
 123    return;
 124 #if 0
 125    int i;
 126
 127    for (i=0xe0000;i<=0xffff0;i++)
 128      {
 129         bios32* service_entry = (bios32 *)physical_to_linear(i);
 130         if ( service_entry->signature != BIOS32_SIGNATURE )
 131           {
 132              continue;
 133           }
 134         DbgPrint("Signature detected at %x\n",i);
 135         if (!checksum(service_entry))
 136           {
 137              continue;
 138           }
 139         DbgPrint("ReactOS: BIOS32 detected at %x\n",i);
 140         bios32_indirect.address = service_entry->entry;
 141         bios32_detected=TRUE;
 142      }
 143 #endif
 144 }