Where can I find programming info :: PCI

The official PCI web site is located at www.pcisig.com

This PCI Special Interest Group site contains a little information on PCI as Microsoft Word 6 document files which are the official specifications, it also contains a few test/diagnostic programs in C for working with PCI that you can download and also they keep a list of Vendor ID numbers but not product ID numbers.

Alternatively, two good sites that seem to be the mainstay for collecting a database on Equipment vendor ID's and Product ID's are;

Craig "Merlin" Hart's PCI page http://members.hyperlink.net.au/~chart/pci.htm
Jim Boemler's PCI page http://www.halcyon.com/scripts/jboemler/pci/pcicode
Ralf Brown's page http://www.cs.cmu.edu/afs/cs.cmu.edu/user/ralf/pub/WWW/files.html


I heard you can do PCI BIOS calls in pmode?

True! You can call the PCI bios functions from pmode and its quite easy to do, and it does not require any mode switching back into real-mode to do it.

First thing is, you have to locate the BIOS32 service directory entry point. This is done by scanning for the 4 bytes of "magic" that is "_32_" (0x5F32335F). The BIOS32 SD can lie in memory from 0xE0000 to 0x100000 and it always lies on a paragraph alignment.

CALL xxxxh:xxxxh - BIOS32 Service Directory
InstallCheck:	scan paragraph boundaries E000h to FFFFh for signature
		string "_32_", followed by a valid header structure
                (see #F0021)

Notes:	a 32-bit-code alternate PCI BIOS entry point may be found (if
	supported) by requesting the entry point for the API with
        identifier "$PCI".
	an alternate entry point for INT 1A/AH=B4h may be found (if
        supported) by requesting the entry point for the API with
        identifier "$ACF"
	other known identifiers are "$WDS" and "MPTN"
SeeAlso: INT 1A/AX=B100h

Format of BIOS32 Service Directory header structure:
Offset	Size	Description	(Table F0021)
 00h  4 BYTEs	signature "_32_"
 04h	DWORD	physical address of BSD entry point (see #F0022)
 08h	BYTE	header structure version number (currently 00h)
 09h	BYTE	header structure length in paragraphs (currently 01h)
 0Ah	BYTE	checksum (8-bit sum of all bytes in structure,
		including this one, should equal zero)
 0Bh  5 BYTEs	reserved (0)

(Table F0022)
Call BIOS32 Service Directory entry point with:
	EBX = function
	    00000000h get service entry point
		EAX = service identifier
		    46434124h ("FCA$") Plug-and-Play Auto-Configuration
		    49435024h ("ICP$") PCI BIOS
		    4E54504Dh ("NTPM") ??? MPTN [PhoenixBIOS4 Rev. 6.0]
		    54435724h ("SDW$") ??? WDS$ [PhoenixBIOS4 Rev. 6.0]
		Return: AL = status
			    00h successful
				 EBX = base address of handler's code seg
				 ECX = size of code segment
				 EDX = offset of handler in code seg
			    80h unknown service identifier
		Return: AL = 81h invalid function
Notes:	the BSD handler assumes that it is running in a 32-bit code
        segment the returned entry points for PCI BIOS and Auto-Config
        must be called with the same registers as the real-mode INT
        1Ah interface, including the value B1h or B4h in AH (AMI BIOS
        v1.00.05.AX1 returns the same entry point for both interfaces
        and uses AH to distinguish which API is desired)

	some references indicate that only BL is used for the function
	number, though at least one implementation actually checks the
        entire EBX register; for maximum compatibility, the upper 24
        bits of EBX should be cleared when calling the entry point
Here is an example of detecting the BIOS32 service directory.
typedef struct BIOS32
	ULONG	magic			__attribute__ ((packed));
	ULONG	phys_bsd_entry		__attribute__ ((packed));
	UCHAR	vers			__attribute__ ((packed));
	UCHAR	prg_lens		__attribute__ ((packed));
	UCHAR	crc			__attribute__ ((packed));
} BIOS32;

BIOS32 *master_bios32;
ULONG bios32_call;

UCHAR search_pci_bios(void)
	UCHAR		*p=(UCHAR*)0xE0000;
	BIOS32		*x;
	UCHAR		flag=0;
	UCHAR		crc;
	int			i;

	while(flag==0 && (ULONG)p<0X100000)
		IF(X->magic==0x5F32335F)		/* _32_ */
			for(i=0, crc=0; i<(X->prg_lens*16); i++)
Once you have located the service directory you can do a far call to its physical entry point and ask it if PCI bios32 calls exist. (PCI v2.0c+)
void bios32_scan_pci_entry(void)
	ULONG	cseg_size, offset, base_addr;

	/* call the BIOS32 BSD for the PCI address
 	   BSD calls terminate in RETF not RET */

	/* eax is loaded with "$PCI" magic */
	asm("movl	$0x49435024, %%eax\n"
		"xorl	%%ebx, %%ebx\n"
		"movl	_bios32_call, %%ebp\n"
		"pushl	%%cs\n"
		"call	%%ebp\n"
		: "=c" (cseg_size),
		  "=d" (offset),
		  "=b" (base_addr)
		: "eax", "ebx", "ecx", "edx", "ebp", "memory" );

	/* setup two new selectors of pci_code32, pci_data32, etc. */
Once you have determined that PCI v2.0c+ BIOS calls exist for pmode applications, you can call the PCI v2.0c+ calls (see INT 0x1A, function 0xB101 down to 0xB18F in Ralf Brown's INT List).