Intel IXP1200 3.0 Microengine Functional Blocks

IXP1200 Network Processor Family ATM OC-3/12/Ethernet IP Router Example Design

20 Application Note

Modified on: 3/20/02,

3. Run the IXP1200 Developer’s Workbench debug library, and connects it to a remote system

host via the PCI Ethernet NIC to download and debug IXP1240 microcode.

Then, atm_init() is invoked to initialize data structures in memory:

•Buffer Descriptor Free-list.

•CRC-32 Lookup Table.

•IP Lookup Table.

•VC Lookup Table and hash miss free-list.

•IP directed broadcast address hash table.

•Ethernet receive port MAC address hash table.

On hardware, atm_init() resides in the atm_utils.o VxWorks-loadable module running on the

StrongARM core. In the simulation environment, atm_init() resides in the atm_util.dll foreign

model and is invoked from the Transactor startup script atm_ether_init.ind.

2.6 Microengine Initialization

One microengine includes system_init.uc and invokes system_init() at its beginning. system_init()

is the central microcode initialization macro. It handles initialization not handled by the

StrongARM core, and then sends a signal to thread0 of every microengine, including itself.

(system_init() can be invoked from any microengine. ether_tx_threads.uc is used simply because

of available microstore space.)

Reset causes every microengine to execute thread0 first, so every microengine begins with thread0

waiting for the inter-thread signal from system_init(). Upon receipt, thread0 is responsible for

starting up the microengine in an orderly fashion, e.g. initializing absolute registers and signaling

the other threads to start.

3.0 Microengine Functional Blocks

3.1 ATM Receive Microengine

The ATM Receive microengine is a single microengine dedicated to receive cells from the ATM

ports, check CRC-32 while re-assembling them into PDUs, and then forward them to the IP Router

microengine. (In the software CRC configuration, an additional microengine is used to handle

CRC checking.)

3.1.1 Structure

The following identifies the ATM Receive microengine structure for OC-12 and OC-3 ports:

OC-12 Port OC-3 Ports

Four threads working in parallel on one port. One thread/port.

Contents

Main Application Note Contents Page Page Figures 1.0 Introduction 1.1 Purpose of ATM Example Design 1.2 Scope of Example Design 1.2.1 Supported / Not Implemented Functions 1.3 Background 1.3.1 Ethernet, IP and AAL5 Protocol Processing 1.3.2 Frame and PDU Length vs. IP Packet Length 1.3.3 Expected Ethernet Transmit Bandwidth 1.4 Execution Environment 1.4.1 Software Page 1.4.2 Hardware 2.0 System Overview 2.1 System Programming Model 2.2 StrongARM Core Software 2.3 Software Partitioning Modified on: 3/20/02, 2.3.1 Lookup Tables Not shown in the diagrams, the microengines make use of either three or four lookup tables: Route microengine and the Ethernet Receive microengine. verification. * Modified on: 3/20/02, 2.4.1.2 IP Lookup Table Modified on: 3/20/02, 2.4.2 Ethernet to ATM D at a Flo w 2.5 StrongARM Core Initialization 2.6 Microengine Initialization 3.0 Microengine Functional Blocks 3.1 ATM Receive Microengine 3.1.1 Structure Application Note 21 Modified on: 3/20/02, 3.1.2 High Level Algorithm Figure 12. ATM Receive High Level Algorithm if(ATM header hits in VC cach 3.2 ATM Transmit Microengine 3.2.1 High Level Algorithm 3.3 IP-Router Microengine 3.3.1 Structure 3.3.2 High Level Algorithm 3.4 Ethernet Receive Microengine 3.5 Ethernet Transmit Microengine 3.5.1 Ethernet Transmit Structure 3.5.2 High Level Algorithm 3.6 CRC-32 Calculations using IXP1240/1250 Hardware 3.6.1 CRC-32 Hardware Checking on Receive Page 3.6.2 CRC-32 Hardware Generation on Transmit 3.6.2.1 Transmit Alignment 3.7 CRC-32 Checker and Generator Microengines (Soft-CRC) 3.7.2 CRC -32 Checker and Generator High Level Algorithm 3.7.3 CRC-32 Computation 4.0 Software Subsystems & Data Structures 4.1 Virtual Circuit Lookup Table - atm_vc_table.uc 4.1.1 VC Table Function Page 4.1.3 VC_TABLE_LINEAR Structure . . . 4.1.4 VC Table Management API - atm_utils.c 4.1.5 VC Table Entry Modified on: 3/20/02, Figure 24. VC Lookup Table Entry (VC_TABLE_LINEAR) 4.2 Virtual Circuit Lookup Table Cache 4.2.1 VC Cache Function 4.2.1.1 OC-12 Configuration 4.2.1.2 OC-3 Configuration 4.2.2 VC Cache Structure 4.2.3 VC Cache API 4.3 IP Lookup Table 4.3.1 IP Table Function 4.3.2 IP Table Structure 4.3.3 IP Table Management API 4.3.3.1 route_table_init() 4.3.3.2 mtu_change() 4.3.3.3 atm_route_add() 4.3.3.4 enet_route_add() 4.3.3.5 rt_ent_info() 4.3.3.6 route_delete() 4.3.3.7 rt_help () 4.3.4 IP Route Table Entry 4.4 SRAM Buffer Descriptors and DRAM Data Buffers Figure 25. IP Route Table Entry - ATM Destination Figure 26. IP Route Table Entry - Ethernet Destination Modified on: 3/20/02, SRAM 4.4.1 SRAM Buffer Descriptor Format Figure 27. SRAM Descriptor to DRAM Buffer Mapping SRAM Figure 28. Buffer Descriptor Format for ATM Transmit Destination Port Modified on: 3/20/02, 4.4.2 DRAM Data Buffer Format Figure 29. Buffer Descriptor Format for Ethernet Transmit Destination Port Figure 30. DRAM Data Buffer Format - 12 Byte Offset (Received by ATM) Figure 31. DRAM Data Buffer Format - 6 Byte Offset (Received by ATM, Transmitted by Ethernet) Figure 32. DRAM Data Buffer Format - 6 Byte Offset (Received by Ethernet, Transmitted by ATM) 4.5 Sequence Numbers - sequence.uc 4.5.1 SEQUENCE_HANDLE Usage 4.5.2 Usage Model 4.5.2.1 Example 4.6 Message Queues - msgq.uc 4.6.1 MSGQ_HANDLE Parameters 4.6.2 msgq_init_queue() 4.6.3 msgq_init_regs() 4.6.4 msgq_send() Modified on: 3/20/02, 4.6.5 msgq_receive() Receives a message from the queue. 4.6.6 Example 4.7 Buffer Descriptor Queues - bdq.uc 4.7.1 BDQ Manag ement Macros 4.7.1.1 Features 4.7.1.2 Limitations 4.8 Counters Page 4.8.2.3 Global Counter Enable and Flags Global Counter Enable and Flags Counter Flags Modified on: 3/20/02, 4.8.3 counters.uc 4.8.3.1 counter_reset() Resets the specified counter to zero. 4.8.3.2 counter_inc() Increments the specified counter. 4.8.3.3 port_counter_inc() port_counter_inc() Algorithm Example Modified on: 3/20/02, 4.8.4 counters.c 4.8.4.1 counters_init() Initializes all counters. 4.8.4.2 counters_print() Prints the names and values of all counters. Example 4.9 Global $transfer Register Name Manager - xfer.uc 4.10 Mutex Vectors 4.10.1 mutex_vector_init() 4.10.2 mutex_vector_enter() 4.10.3 mutex_vector_exit() 4.11 Inter-Thread Signalling 5.0 Project Configuration / Modifying the Example Design 5.1 project_config.h 5.2 system_config.h 5.3 Switching Between Hardware Configurations 6.0 Testing Environments 7.0 Simulation Support (Scripts, etc.) 8.0 Limitations 9.0 Extending the Example Design Modified on: 3/20/02, 10.0 Document Conventions 11.0 Acronyms & Definitions Figure 37. Illustration of Array of 32-bit Words Figure 38. Illustration of Byte Sequence Figure 39. Definitions 12.0 Related Documents Modified on: 3/20/02, Figure 39. Definitions (Continued)