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Detecting PCI devices

On identifying the peripheral

equipment installed in our PC

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Early PCs

Peripheral devices in the early PCs used fixedi/o-ports and fixed memory-addresses, e.g.:

Video memory address-range: 0xA0000-0xBFFFF

Programmable timer i/o-ports: 0x40-0x43 Keyboard and mouse i/o-ports: 0x60-0x64

Real-Time Clocks i/o-ports: 0x70-0x71

Hard Disk controllers i/o-ports: 0x01F0-01F7

Graphics controllers i/o-ports: 0x03C0-0x3CF

Serial-port controllers i/o-ports: 0x03F8-0x03FF

Parallel-port controllers i/o-ports: 0x0378-0x037A

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The PCs evolution

It became clear in the 1990s that therewould be contention among equipmentvendors for fixed resource-addresses,

which of course were in limited supply

Among the goals that motivated the PCISpecification was the creation of a more

flexible scheme for allocating addressesthat future peripheral devices could use

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PCI Configuration Space

PCI Configuration Space Body

(48 doublewords variable format)

64doublewords

PCI Configuration Space Header(16 doublewords fixed format)

A non-volatile parameter-storage area for each PCI device-function

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PCI Configuration Header

StatusRegister

CommandRegister

DeviceID

VendorID

BISTCacheLineSize

Class CodeClass/SubClass/ProgIF

RevisionID

Base Address 0

SubsystemDevice ID

SubsystemVendor ID

CardBus CIS Pointer

reservedcapabilities

pointerExpansion ROM Base Address

MinimumGrant

InterruptPin

reserved

LatencyTimer

HeaderType

Base Address 1

Base Address 2Base Address 3

Base Address 4Base Address 5

InterruptLine

MaximumLatency

31 031 0

16 doublewords

Dwords

1 - 0

3 - 2

5 - 4

7 - 6

9 - 8

11 - 10

13 - 12

15 - 14

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Three IA-32 address-spaces

memoryspace(4GB)

i/o space(64KB)

PCIconfiguration

space(16MB)

accessed using a large variety of processor

instructions (mov, add, or, shr, push, etc.)and virtual-to-physical address-translation

accessed only by using the processorsspecial in and out instructions

(without any translation of port-addresses)

i/o-ports 0x0CF8-0x0CFF dedicated to accessing PCI Configuration Space

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reserved

Interface to PCI Configuration Space

CONFADD

( 0x0CF8)

CONFDAT( 0x0CFC)

31 23 16 15 11 10 8 7 2 0

EN

bus

(8-bits)

device

(5-bits)

doubleword

(6-bits)

function(3-bits) 00

PCI Configuration Space Address Port (32-bits)

PCI Configuration Space Data Port (32-bits)

31 0

Enable Configuration Space Mapping (1=yes, 0=no)

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Reading PCI Configuration Data

Step one:Output the desired longwordsaddress (bus, device, function, and dword)with bit 31 set to 1 (to enable access) to

the Configuration-Space Address-Port

Step two: Read the designated data fromthe Configuration-Space Data-Port:# read the PCI Header-Type field (byte 2 of dword 3) for bus=0, device=0, function=0

movl $0x8000000C, %eax # setup address in EAXmovw $0x0CF8, %dx # setup port-number in DXoutl %eax, %dx # output address to port

mov $0x0CFC, %dx # setup port-number in DXinl %dx, %eax # input configuration longword

shr $16, %eax # shift word 2 into AL registermovb %al, header_type # store Header Type in variable

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Demo Program

We created a short Linux utility that searches forand reports all of your systems PCI devices

Its named pciprobe.cpp on our CS635 website

It uses some C++ macros that expand to Intelinput/output instructions -- which normally areprivileged instructions that a Linux application-program is not allowed to execute (segfault!)

Our system administrator (Alex Fedosov) hascreated a utility (named iopl3) that will allowyour command-shell to acquire I/O privileges

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Example: network interface

We identify the network interface controller inour classroom PCs by class-code 0x02

The subclass-code 0x00 is for ethernet

We can identify the NIC from its VENDOR andDEVICE identification-numbers:

VENDOR_ID = 0x14E4

DEVICE_ID = 0x1677

You can use the grep command to search for

these numbers in this header-file:

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Vendors identity

The VENDOR-ID 0x14E4 belongs to theBroadcom Corporation (headquarters inIrvine, California)

Information about this firm may be learnedfrom the corporations website:

The DEVICE-ID 0x1677 is used to signifyBroadcoms BCM5751 ethernet product

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nic

Typical NIC

TX FIFO

RX FIFO

transceiver LANcableB

US

mainmemory

packet

buffer

CPU

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Packet filtering capability

Network Interfaces hardware needs to

implement filtering of network packets

Otherwise the PCs memory-usage andprocessor-time will be wasted handlingpackets not meant for this PC to receive

network packets layout

Destination-address (6-bytes) Source-address (6-bytes)

Each data-packet begins with the 6-byte device-addressof the network interface which is intended to receive it

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Your NICs unique address

You can see the Hardware Address of theethernet controller on your PC by typing:

$ /sbin/ifconfig

Look for it in the first line of screen-outputthat is labeled eth0, for example:

(The NICs filter-register stores this value)

eth0 Link encap: Ethernet HWaddr 00:11:43:C9:50:3A

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Our tigon3.c demo

We wrote a kernel module that lets userssee certain register-values which pertainto the BCM5751 network interface in your

classroom workstation: (1) the PCI Configuration Space registers

(2) the Media Access Controllers address

It also shows your machines node-name(in case you want to save the information)

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How we got the MAC-address

We do not have Broadcoms programming

datasheet -- but we do have Linux sourcecode for the tigon3 device-driver, which

includes a header-file tg3.h found here:

If you scroll through the #define directives

you will see the offset where the hardwareaddress is stored in the memory-mappedregister-space of the tigon3 interface

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Drivers authors

The Linux kernels open-source driver forthe Broadcom tigon3 network controller

was jointly written by David S. Miller (see

photo below) and Jeff Garzik

David Millers announcement in Feb 2002of their drivers BETA version is online.

It includes his candid comments aboutthe challenge of writing such a driver whenthe vendor does not make available itsdevices programming documentation.

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How we got tigon3 registers

StatusRegister

CommandRegister

DeviceID0x1677

VendorID0x14E4

BISTCacheLineSize

Class CodeClass/SubClass/ProgIF

RevisionID

Base Address 0

SubsystemDevice ID

SubsystemVendor ID

CardBus CIS Pointer

reservedcapabilities

pointerExpansion ROM Base Address

MinimumGrant

InterruptPin

reserved

LatencyTimer

HeaderType

Base Address 1

Base Address 2Base Address 3

Base Address 4Base Address 5

InterruptLine

MaximumLatency

31 031 0

16 doublewords

Dwords

1 - 0

3 - 2

5 - 4

7 - 6

9 - 8

11 - 10

13 - 12

15 - 14

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Linux helper-functions

#include

struct pci_dev *devp;unsigned int iomem_base, iomem_size;void *io;

devp = pci_get_device( 0x14E4, 0x1677, NULL );if ( !devp ) return ENODEV;

iomem_base = pci_resource_start( devp, 0 );

iomem_size = pci_resource_len( devp, 0 );

io = ioremap( iomem_base, iomem_size );if ( !io ) return -EBUSY;

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Big-Endian to Little-Endian

mac1

mac0

mac5

mac4

mac3

mac2

0x0410 0x0411 0x0412 0x0413 0x0414 0x0415 0x0416 0x0417Broadcom network interface storage-addresses

Intel IA-32 character-array storage

mac0

mac1

mac2

mac3

mac4

mac5

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In-class exercise

Copy the tigon3.c source-module to yourown directory, then rename it anchor.c

Your assignment is to modify it so that it

will show information about the Intel NICsin our anchor clusters machines:

#define VENDOR_ID 0x8086 // Intel Corp

#define DEVICE_ID 0x109A // 82573L NIC

Intels filter-register at offset 0x5400 usesthe little endian storage-convention

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Little-Endian to Little-Endian

mac0

mac1

mac2

mac3

mac4

mac5

0x5400 0x5401 0x5402 0x5403 0x5404 0x5405 0x5406 0x5407Intel network interface storage-addresses

Intel IA-32 character-array storage

mac0

mac1

mac2

mac3

mac4

mac5