Changeset 2019 for Whitix

Timestamp:

04/02/09 21:21:10 (3 years ago)

Author:

mwhitworth

Message:

Attempt to rework PCI BIOS, add note.

Files:

• Whitix/trunk/devices/pci/pci_bios.c (modified) (2 diffs)

Whitix/trunk/devices/pci/pci_bios.c

@@ -17 +17 @@
  */
 
+/* TODO: This code needs checking, if it is ever used. */
 
 #include <i386/ioports.h>
@@ -27 +28 @@
 BYTE bios32FarCall[6];
 
-int PciDetectBios()
+static DWORD PciScanForBios(DWORD start, DWORD end)
 {
-#if 0
-        DWORD addr=0xE0000,name,temp;
-        BYTE length,sum,revision,err;
-
-        for (;addr < 0xFFFF0; addr+=16)
+        DWORD curr;
+        BYTE length, sum;
+        
+        for (curr = start; curr < end; curr += 16)
         {
-                printf("Here, %#X\n", addr);
-                name=*(DWORD*)addr;
-                if (name != 0x5F32335F)
+                if (*(DWORD*)curr != BIOS32_SIGNATURE)
                         continue;
-
-                //Structure length
-                length=(*(BYTE*)addr+9)*16;
+                        
+                /* Get the length of the BIOS32 descriptor. It should not be zero. */
+                length=(*(BYTE*)curr+9)*16;
 
                 if (length == 0)
                         continue;
 
+                /* Checksum, to make sure we have a valid BIOS32 descriptor. */
                 for (sum=0; length!=0; length--)
-                        sum+=*(BYTE*)((addr+length)-1);
+                        sum+=*(BYTE*)((curr+length)-1);
+                
+                return curr;
+        }
+        
+        return 0;
+}
 
-                *(DWORD*)(bios32FarCall+0)=*(DWORD*)(addr+4);
-                *(WORD*)(bios32FarCall+4)=0x08;
+int PciDetectBios()
+{
+        DWORD name,temp;
+        DWORD addr;
+        BYTE revision, err;
 
-                asm volatile("mov $0x49435024,%%eax\n"
+        addr = PciScanForBios(0xE0000, 0xffff0);
+
+        if (!addr)
+        {
+                KePrint(KERN_ERROR "PCI: Could not find BIOS32.\n");
+                return -EINVAL;
+        }
+
+        *(DWORD*)(bios32FarCall+0)=*(DWORD*)(addr+4);
+        *(WORD*)(bios32FarCall+4)=0x08;
+
+#if 0
+        asm volatile("mov $0x49435024,%%eax\n"
                              "mov 0,%%ebx\n"
                              "lcall *(%%edi)"
                              : "=a"(err),
-                                "=b"(addr),
-                                "=c"(length),
-                                "=d"(temp)
+                                 "=b"(addr),
+                                 "=c"(length),
+                                 "=d"(temp)
                              :  "D"(&bios32FarCall));
 
-                if (err == 0x80)
-                {
-                        printf("Computer has BIOS32, but no PCI32\n");
-                        return false;
-                }
+        if (err == 0x80)
+        {
+                KePrint("PCI: BIOS32 present, but no PCI32\n");
+                return -EINVAL;
+        }
 
-                if (err)
-                {
-                        printf("BIOS32 error = %u\n",(DWORD)err);
-                        return false;
-                }
+        if (err)
+        {
+                printf("PCI: BIOS32 error\n");
+                return -EINVAL;
+        }
 
                 return true;