pci express analyzer

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PCI Express Analyzer

High speed digital systems laboratoryהמעבדה למערכות ספרתיות מהירות

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הטכניון - מכון טכנולוגי לישראל

Technion - Israel institute of technology

Final Presentation

Samuel Amir , Danny Volkind

Mr. Orbach Mony

Analyzer Core

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Agenda

• PCI - Express – Reminder

• Link and Lane Training - Overview

• Project Goals

• Project features and capabilities

• PCI-Express Generator - Brief

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Agenda (cont.)

• Project Block Diagram

• Demonstration

• Future Improvement Procedures

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PCI - Express

Reminder

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PCI-Express Topology

Ref. Clock Ref. Clock

Dev

ice

A Device B

TX+TX-

RX+RX-

TX+TX-

RX-RX+


• Differential

• Dual Simplex

• Speeds of 2.5Gb/sec

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Packet Formation

Packet formation reflects

layered architecture.


Transaction

Data Link

Physical

Transaction Layer

DataHeader

Data Link Layer

CRCSequenceNumber

Physical Layer

FrameFrame

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8/10b conversion (4.2.1)

8b/10b Encoded Byte Value

Byte Value 00H

• Convert each byte to a 10bit character according to a pre-

defined table.

• Extra characters are used as control characters or not used.

• Embedded clocking-> No need to add clock traces.

• Error detection (running disparity).

• DC balancing

• Reduces ISI.

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PCI Express scrambling (4.2.3)• Assures no constant pattern is transmitted.

• Spread the energy transmitted in one frequency to

different frequencies-> reduces EMI! (and gets FCC

approval)

• Only data characters are encoded.

• Encoding is done using a linear feedback shift register.

• Decoding is done using the same process at the receiver

side.

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Frequency Mismatch (4.2.7)

How does the protocol cope with the fact that each

device is feed by a different clock source?

Ref. Clock Ref. Clock

Dev

ice

A Device B

TX+TX-

RX+RX-

TX+TX-

RX-RX+

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Frequency Mismatch (4.2.7)

Input @ 2501MHz Output @ 2500MHz

Input Shift Register is filling up faster than it is emptied!

Input @ 2500MHz Output @ 2501MHz

Input Shift Register is emptied faster than it is filled!

If we take 600ppm difference between clocks, the

transmitter and receiver clocks can shift one clock

every 1666 clocks!

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Frequency Mismatch-Solution• The protocol issues a SKIP ordered set that can be

skipped so that the input shift register can be partially

cleared!

• The SKIP ordered sets insertion time as dictated by the

protocol is between 1180 and 1538 symbol times.

• Calculated allowed deviance : ± 300ppm !

• This is known as “clock tolerance compensation

mechanism”.

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Link & Lane

Training

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Link and Lane Training


Lane - a single set of differential RX TX pairs

Link - a collection of lanes connecting two

PCI-Express Devices.

Dev

ice

A Device B

TX+TX-

RX+RX-

TX+TX-

RX-RX+

x1 Lane wide Link

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Link and Lane Training (cont)


Training - a process aimed at turning a collection of

available lanes into a properly functioning link.

Elements established during training :• Physical Level

• SERDES lock.• Symbol alignment.

• Link Level link configuration• Link data rate• Link width• Etc.

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Link and Lane Training (cont)


Configuration

Disable

Polling Loopback

Detect

HotReset

Recovery

L0s

L2

L3

L0(Full On)

L2/L3Ready

L1

Link Training States

Link Power Manaement States

Active Power Management States

To Detect

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Training Ordered Sets


• Group of 16 symbols.• Used During Polling State (TS1,TS2)• Establish alignment• Exchange Physical layer parameters• Not scrambled!

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Training Ordered Sets (cont)


TS1

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Fast Training Sequence


Used to re-establish bit and symbol lock when transitioning out of the LO power management state.

K28.1K28.1K28.1K28.5

FTS pattern

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Skipped Ordered Set (CTC)


Compensate for differences in frequencies between bit rates at two devices sharing a mutual Link (Clock Tolerance Compensation)

Skipped Ordered Set pattern

K28.0K28.0K28.0K28.5

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Electrical Idle


• Steady state condition• Transmitter differential pair held at fixed value• Must remain at this state at least 20nsec• Must attempt to detect a receiver within 100msec

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DLLP packet

DLLP ContentsDLLP Contents44bytebyte

CRCCRC2byte2byte

Data Link LayerData Link Layer

FrameFrame1byte1byte


Physical Layer

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TLP packet

Transaction LayerTransaction Layer

Data0-4Kbyte

Header12/16byte


LCRCLCRC4byte4byte

Sequence#Sequence#2byte2byte

Physical Layer



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Packet Header

FmtFmt

Address/RoutingAddress/Routing

TypeType Requestor IDRequestor ID RsrvRsrv Traffic ClassTraffic Class

LengthLength AttrAttr TagTag

16/1216/12ByteByte

RsrvRsrv Byte EnablesByte Enables

Data PayloadData PayloadIndicator and Indicator and

16/12B header flag16/12B header flag

Memory, I/O, Config,Memory, I/O, Config, Message; RequestMessage; Request

or Completionor Completion

Bus#, Device#, Bus#, Device#, Function#,Function#,

Virtual ChannelVirtual ChannelSupportSupport

TransactionTransactionTagTag

ReservedReservedfor futurefor futureexpansionexpansion

Attributes:Attributes:Snoop,Snoop,

OrderingOrdering

First DW BE;First DW BE;Last DW BELast DW BE

RequestedRequestedLength or Length or

Payload SizePayload Size

Header

Transaction LayerTransaction Layer

Data


CRCSequenceNumber

Physical LayerPhysical Layer

FrameFrame

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Project Goals

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Project Goal Overview• PCI-Express packets capturing at wire speed of 2.5Gbps

• Selective filtering – work modes

• TLP analysis – header based filtering

• Simple register based user interface

• RS232 accessible.

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Project Features

&

Capabilities

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Project features


• Receiving PCIe communication at 2.5 Gbps.

• Full line synchronization capability according

to PCIe spec.

• Handling of realignment and clock tolerance

compensation events on the fly.

• Invalid symbol filtering.

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Project features (cont.)


• Detection of and field extraction for all PCIe training

sequences.

• Selective descrambling of the received data.

• Accumulative user-controlled counters for statistic

purposes.

• Data stream marking and preliminary analysis.

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Projects features (cont.)• 6 Available work modes:

• Wire Speed Capture.

• Capture TS1 / TS2

• Capture DLLP

• Capture TLP

• Selective TLP capture


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Projects features (cont.)•TLP filtering versatility:


TLP Type field 5 Bit

TLP format field 2 Bit

TLP Traffic Class 3 Bit

TLP length 10 Bit

TLP Attribute 2 Bit

TLP Tag 8 Bit

TLP Byte Enables or Message 8 Bit

TLP Sequence num 12 Bit

TLP Bus num 8 Bit

TLP device number 5 Bit

TLP function number 3 Bit

TLP poisoned packet 1 Bit

TLP Type field Mask 5 Bit

TLP format field Mask 2 Bit

TLP Traffic Class Mask 3 Bit

TLP length Mask 10 Bit

TLP Attribute Mask 2 Bit

TLP Tag Mask 8 Bit

TLP Byte Enables or Message Mask 8 Bit

TLP Sequence num Mask 12 Bit

TLP Bus num Mask 8 Bit

TLP device number Mask 5 Bit

TLP function number Mask 3 Bit

TLP poisoned packet Mask 1 Bit

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•Storage

• Fully user controlled dynamically allocated

16K x 32 memory.

• Captured data is saved with preliminary

analysis.

• Bursts and capture events are separated

allowing selective extraction.

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• LCD Interface

• Built-in LCD micro-controller implementation.

• 1 Kbyte user memory for display commands.

• Display file can be loaded on the fly.

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• User Interface

• RS232 serial link operating at 115.2Kbps.

• Simple comm. protocol implementation

allowing read and write commands accessing

32bit address space with 16bit data.

• All the core features are accessible.

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Generator - Overview• Capable of generating all PCIe traffic.

• Fully user-controlled.

• PCIe compatible including clock tolerance

compensation simulation.

• Can be set to continuous or single shot mode.

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Generator - Overview

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Basic Block Diagram

PCIe

MCL PDM

SDMPLA

Modular Single-channel UnitSDRAM

MCSU

AD

DR

DA

TA

CCIU

LQAM MGR

Gigabit Receiver1

1

Decryption Module2

Wrap Filter3

Packet Filter4

MSU Control5

Link Assessment6

2

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5

6 Memory Controller7

Central Controller8

7

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Physical

Physical

Transaction

Physical

Physical

Data Link

Transaction

Physical Data Link

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Modular Single-channel Unit

MGR

SDM

LQAM

MCSU

PLA

PDM

PCIe

MCL

CCIU

Modular Single-channel Unit#2

PCIe

SDRAM8Mx16

SDRAM8Mx16

Addr

Data

Control

Data

Top Level


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Project Block Diagram

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PDM – LFSR


8 bit values generated by LFSR for repeated data value of 0

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PDM – LFSR (cont)


Scrambling spectral power distribution for repeated data value of 0

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PDM – LFSR (cont)


Reset Value (Comma)

Figure 1

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PDM – LFSR (cont)


LFSR1_out

LFSR2_out

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Demonstration

AnalyzerAnalyzer

Frame

Frame

Dev

ice

AD

evice B

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Future Developments


• Additional functions.

• User interface development.

Open Code flexibility opens the door for development

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Closing Words

Thank You !


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Additional informationCertain images adopted from PCI-SIG PCI Express™ Architectural Overview Presented at the 2002 PCI-SIG Developers Conference and Intel Developers Forum, Fall 2001.


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Project Development Process

High Speed Communication Fundamentals

Semester A

Final ConceptRequirements Doc

PCI ExpressArchitecture Concepts

market surveyCurrent Available Products

Existing Infrastructure

Constructing Analyzer CoreBuilding Blocks

Semester B

Analyzer CoreDevelopment report

Debugging & TestingEach block

Final Core Integration


pci express analyzer

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