Version 1.3 2009 Features PEX 8615 General Features o 12-lane PCI Express switch - Integrated 5.0 GT/s SerDes o Up to 12 configurable ports o 19 x 19mm2, 324-ball HSBGA o Typical Power: 1.79 Watts PEX 8615 Key Features o Standards Compliant - PCI Express Base Specification r2.0 (Backwards compatible with PCIe r1.0a/1.1) - PCI Power Management Spec r1.2 - Microsoft Vista Compliant - Supports Access Control Services - Dynamic link-width control o Integrated DMA Engine - Four DMA Channels - Internal Descriptor Support - DMA function independent from transparent switch function - 64-bit Addressing - Prefetch Descriptor Mode - Up to 4.0 GB/s throughput per channel o Dual-Host & Fail-Over Support - Configurable Non-Transparent port (NTB) - Moveable upstream port - Crosslink port capability o High Performance - Cut-Thru latency: 140ns - 2KB max payload size - Read Pacing - Dual-Cast o Flexible Configuration - 12 flexible & configurable ports (x1 or x4) - Configurable with strapping pins, EEPROM, I2C, or Host software - Lane and polarity reversal o PCI Express Power Management - Link power management states: L0, L0s, L1, L2/L3 Ready, and L3 - Device states: D0 and D3hot o Spread Spectrum Clock Isolation - Dual clock domain o Quality of Service (QoS) - Two Virtual Channels (VC) per port - Eight Traffic Classes per port - Weighted Round-Robin Port & VC Arbitration o Reliability, Availability, Serviceability - All ports Hot-Plug capable thru I2C (Hot-Plug Controller on every port) - Data path protection - Memory (RAM) error correction - Port Status bits and GPIO available - Per port error diagnostics - Performance monitoring (per port payload & header counters) PEX 8615 Flexible & Versatile 12-lane 12-port PCI Express® Switch The ExpressLane™ PEX 8615 device offers PCI Express switching capability enabling users to add scalable high bandwidth non-blocking interconnection to a wide variety of applications including control planes, communication platforms, servers, storage systems and embedded systems. The PEX 8615 is well suited for fan-out, aggregation, peer-to-peer, and intelligent I/O module applications. Low Packet Latency & High Performance The PEX 8615 architecture supports packet cut-thru with a maximum latency of 140ns. This, combined with large packet memory and non-blocking internal switch architecture, provides full line rate on all ports for low-latency applications such as communications and servers. The low latency enables applications to achieve high throughput and performance. In addition to low latency, the device supports a max payload size of 2048 bytes, enabling the user to achieve even higher throughout. Integrated DMA Engine The PEX 8615 provides a versatile and powerful DMA engine built in to the device which can be used as a stand alone DMA engine. The DMA engine removes the burden resulting from having to move data between devices away from the processor. This allows the processor to perform computational tasks instead. The four DMA channels can support high data rate transfers between IO devices connected to any of the available ports in the PEX8615. Additionally, the DMA engine in the PEX 8615 can be used to complement the DMA engine in the processor by providing additional DMA channels for higher performance. Data Integrity The PEX 8615 provides end-to-end CRC protection (ECRC) and Poison bit support to enable designs that require guaranteed error-free packets. PLX also supports data path parity and memory (RAM) error correction as packets pass through the switch. Dual-Host and Fail-Over Support The PEX 8615 supports full non-transparent bridging (NTB) functionality to allow implementation of multi-host systems and intelligent I/O modules in applications which require redundancy support such as communications, storage, and servers. Non-transparent bridges allow systems to isolate host memory domains by presenting the processor subsystem as an endpoint rather than another memory system. Base address registers are used to translate addresses; doorbell registers are used to send interrupts between the address domains; and scratchpad registers are accessible from both address domains to allow inter-processor communication. Interoperability The PEX 8615 is designed to be fully compliant with the PCI Express Base Specification r2.0 and is backwards compatible to PCI Express Base Specification r1.1 and r1.0a. Additionally each port supports auto-negotiation, lane reversal and polarity reversal. Furthermore, the PEX 8615 is designed for Microsoft Vista compliance. All PLX switches undergo thorough interoperability testing in PLX’s Interoperability Lab and compliance testing at the PCI-SIG plug-fest to ensure compatibility with PCI Express devices in the market. Flexible Port Configurations The PEX 8615 supports a large number of port configurations as shown in figure 1 below. Please refer to the PEX 8615 datasheet for more port configuration options. off, low, typical, and high. The SerDes block also supports loop-back modes and advanced reporting of error conditions, which enables efficient debug and management of the entire system. Port and Virtual Channel (VC) Arbitration The PEX 8615 switch supports hardware fixed and Weighted Round-Robin Ingress Port Arbitration. This allows fine tuning of Quality of Service and efficient use of packet buffers for better system performance. The PEX 8615 also supports WRR VC arbitration scheme between the two virtual channels. Applications Suitable for fan-out, control plane applications, embedded systems as well as intelligent I/O applications, PEX 8615 can be configured for a wide variety of form factors and applications. Figure 1. PEX8615 Port Configurations Hot-Plug for High Availability Hot-Plug capability allows users to replace hardware modules and perform maintenance without powering down the system. The PEX 8615 Hot-Plug capability feature makes it suitable for High Availability (HA) applications. If the PEX 8615 is used in an application where one or more of its downstream ports connect to PCI Express slots, each port’s Hot-Plug Controller can be used to manage the Hot-Plug event of its associated slot. Every port on the PEX 8615 is equipped with a Hot-Plug control/status register to support Hot-Plug capability through external logic via the I2C interface. Fan-Out The PEX 8615 switch, with its high port count and flexible configurations, allows user specific tuning to a variety of hostcentric as well as peer-to-peer applications. Dual Cast The PEX 8615 supports Dual Cast, a feature which allows for the copying of data (e.g. packets) from one ingress port to two egress ports allowing for higher performance in storage, security, and mirroring applications. Read Pacing The Read Pacing feature allows users to throttle the amount of read requests being made by downstream devices. In the case where a downstream device requests several long reads backto-back, the Root Complex gets tied up in serving this downstream port. If this port has a narrow link and is therefore slow in receiving these read packets from the Root Complex, then other downstream ports may become starved – thus, impacting performance. The Read Pacing feature enhances performances by allowing for the adequate servicing of all downstream devices by intelligent handling of read requests. SerDes Power and Signal Management The PEX 8615 provides low power capability that is fully compliant with the PCI Express power management specification. In addition, the SerDes physical links can be turned off when unused for even lower power. The PEX 8615 supports software control of the SerDes outputs to allow optimization of power and signal strength in a system. The PLX SerDes implementation supports four levels of power – Figure 2. Fan-in/out Usage Figure 2 shows a typical fan-out design, where the processor provides a PCI Express link that needs to be fanned into a larger number of smaller ports for a variety of I/O functions, each with different bandwidth requirements. In this example, the PEX 8615 would typically have a 1-lane upstream port, and as many as 11 downstream ports. The downstream ports provide x1 PCI Express connectivity to the endpoints. With its twelve ports, the PEX 8615 can provide fan-out connectivity to up to eleven PCI Express devices. The figure also shows how some of the ports can be bridged to provide PCI slots or Generic devices through the use of the PEX 8311 and PEX 8112 PCIe bridging devices. Control Plane Application The PEX 8615 is ideal for control planes in routers and other communications sub-systems to meet increased packet processing needs without compromising latency. Figure 3 shows a controller card with a PEX 8615 connecting the Control Processor to as many as eleven line cards each via an x1 connection. This usage model provides connectivity to multiple line cards giving the processor control over a large number of line cards in communication platforms. Figure 5. Distributed Computing Intelligent Adapter Card Redundancy The PEX 8615 supports the non-transparency feature. Figure 6 illustrates a host system using an intelligent adapter card. Figure 6. Intelligent Adapter Usage Figure 3. Control Plane Application DMA in Control Planes for Large Systems The DMA engine in the PEX8615 can alternatively be used to perform housekeeping tasks, such as reading device status information from the many endpoints available. This particular usage model allows the DMA engine to perform the many data transfers for endpoint status that would otherwise be handled by the processor. In this figure, the CPU on the adapter card is isolated from the host CPU. The PEX 8615 non-transparent port allows the two CPUs to be isolated but communicate with each other through various registers that are designed in the PEX 8615 for that purpose. Moreover, the internal DMA engine can be used to copy or mirror the data between adapter cards so that intelligent I/O adapter redundancy is achieved. This model can be expanded to an Active-Standby failover model. In this case, there is an Active host and a Standby host ready to take over the system in the event the Active host fails. The DMA engine in the PEX8615 can be used to mirror the data between hosts thus minimizing the failover time. Generic Data Mover Figure 4. PEX8615 DMA in a Packet Router Distributed Computing The PEX 8615 is well suited for distributed computing applications. Once programmed, the DMA engine in the PEX8615 transfers the data between servers and through the NT port at a high rate. The processor can focus all of its computing cycles manipulating the large amounts of data received. The DMA engine in the PEX8615 is very flexible. It implements Four DMA channels capable of saturating a x8 Gen2 PCI Express link. Furthermore, it supports a Descriptor Ring approach in which the descriptors can be placed in external host memory or internal to the PEX8615. The DMA engine can move data from any port to any port including the same port. That is, the source and destination for a DMA transfer can be on the same PEX8615 port. Figure 7 shows two PCIe endpoints and a PEX8615 device connected through a PCIe switch. In this example, the PCIe endpoints take advantage of the DMA capabilities in the PEX8615 to move data from PCIe2 to PCIe1. Figure 7. Generic Data Mover Software Usage Model Interrupt Sources/Events The PEX8615 is a multi-function device. Function 0 implements the function of a transparent PCI Express switch while Function 1 implements the endpoint functionality of the DMA. From a system model viewpoint, each PCI Express port is a virtual PCI to PCI bridge device and has its own set of PCI Express configuration registers. It is through the upstream port that the BIOS or host can configure the other ports using standard PCI enumeration. The DMA function of the PEX8615 implements a Type 0 header, same as an endpoint, and requires a driver. The driver for the DMA function is available from PLX and included in the SDK. The PEX 8615 supports the INTx interrupt message type (compatible with PCI 2.3 Interrupt signals) or Message Signaled Interrupts (MSI) when enabled. Interrupts/messages are generated by PEX 8615 for Hot-Plug events, doorbell interrupts, baseline error reporting, and advanced error reporting. Development Tools RDK PLX offers hardware and software tools to enable rapid customer design activity. These tools consist of a PEX 8615 Rapid Development Kit (RDK), hardware documentation, and a Software Development Kit (also available at www.plxtech.com/sdk). The PEX 8615RDK is a hardware module containing the PEX 8615 which plugs right into your system (Figure 8). The PEX 8615RDK hardware module can be installed in a motherboard, used as a riser card, or configured as a bench-top board. The PEX 8615RDK can be used to test and validate customer software. Additionally, it can be used as an evaluation vehicle for PEX 8615 features and benefits. SDK The SDK tool set includes: - Linux & Windows drivers - C/C++ Source code, Objects, libraries - User’s Guides & Application examples Windows/Linux Apps User Space PEX API Kernel Space Hardware PCIe Driver NT PnP Driver PCI Express Interface Figure 8. PEX 8615RDK Product Ordering Information PLX Technology, Inc. 870 W. Maude Ave. Description Sunnyvale, CA 94085 USA Part Number PEX8615-BA50BC 12 Lane, 12 Port PCIe Switch, 324-ball HSBGA 19x19mm2 pkg Tel: 1-800-759-3735 PEX8615-BA50BC G 12 Lane, 12 Port PCIe Switch, 324-ball HSBGA 19x19mm2 pkg, Pb-free Tel: 1-408-774-9060 PEX 8615BA-BB4U1D RDK PEX 8615 Base Board Kit; x4 Upstream; x1 downstream (8) Fax: 1-408-774-2169 PEX8615BA-AIC4U4D RDK PEX8615 Add-in Card Kit; x4 Upstream; x4 downstream (2) [email protected] www.plxtech.com Please visit the PLX Web site at http://www.plxtech.com or contact PLX sales at 408-774-9060 for sampling. © 2009 by PLX Technology, Inc. All rights reserved. PLX and the PLX logo are registered trademarks of PLX Technology, Inc. ExpressLane is a trademark of PLX Technology, Inc., which may be registered in some jurisdiction. All other product names that appear in this material are for identification purposes only and are acknowledged to be trademarks or registered trademarks of their respective companies. Information supplied by PLX is believed to be accurate and reliable, but PLX Technology, Inc. assumes no responsibility for any errors that may appear in this material. PLX Technology, Inc. reserves the right, without notice, to make changes in product design or specification. PEX8615-SIL-PB-1.3 5/09