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RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
PM7326 S/UNI TM
APEX
S/UNI-APEX
ATM/PACKET TRAFFIC MANAGER AND SWITCH
ERRATA
RELEASED ISSUE 1: APRIL 2000
PMC-Sierra, Inc.
105 - 8555 Baxter Place Burnaby, BC Canada V5A 4V7 604 .415.6000
RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
REVISION HISTORY
Issue No. Issue 1
Issue Date April, 2000
Details of Change Initial release of errata.
PMC-Sierra, Inc.
105 - 8555 Baxter Place Burnaby, BC Canada V5A 4V7 604 .415.6000
RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
CONTENTS 1 INTRODUCTION...........................................................................................1 1.1 1.2 1.3 2 REFERENCES ....................................................................................1 ORGANIZATION..................................................................................1 ADDITIONAL FEEDBACK ...................................................................1
FUNCTIONAL DEFICIENCIES .....................................................................2 2.1 2.2 SERVICE ARBITRATION ROUND-ROBIN BEHAVIOR ......................2 ANY-PHY BUS, RSX SIGNAL TIMING RESTRICTION.......................4
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS' INTERNAL USE
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RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
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PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS' INTERNAL USE
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RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
1
INTRODUCTION This document is complete list of all errata items associated with the PM7326 S/UNI-APEX, Revision A.
1.1
References The information contained in this errata document applies to the following product documents: PMC-981224, PM7326 S/UNI-APEX ATM/Packet Traffic Manager and Switch Data Sheet, Issue 6, May, 1999. PMC-991454, PM7326 S/UNI-APEX Hardware Programming Guide, Issue 2, March, 2000. PMC-991727, PM7326 S/UNI-APEX Driver Manual, Issue 1, December, 1999.
1.2
Organization Each item in this document is grouped according to the type of errata and contains the following information: * * * * Descriptive title Document reference(s) Detailed description of item Additional relevant information
1.3
Additional Feedback Please report any discrepancies not covered in this document to PMC-Sierra at: PMC-Sierra, Inc. 105-8555 Baxter Place Burnaby, BC, Canada V5A 4V7 Tel: (604) 415-6000 App Support: (604) 415-4533 Fax: (604) 415-6001 Product information: info@pmc-sierra.com Applications information: apps@pmc-sierra.com Web Site: http://www.pmc-sierra.com
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS' INTERNAL USE
1
RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
2
FUNCTIONAL DEFICIENCIES This section describes known functional deficiencies of the S/UNI-APEX, as of the publication date of this document.
2.1
Service Arbitration Round-Robin Behavior Document Reference S/UNI-APEX ATM/Packet Manager and Switch Data Sheet, Sections 10.9.1 and 10.9.2.2 Description Note that the behavior described below will only impact you if you are operating the S/UNI-APEX in frame continuous queuing mode. In very limited circumstances, the service arbitration process may be inconsistent with the description shown in Section 10.9.1 of the data sheet. Referring to Figure 14 in the data sheet (reproduced below), in some cases the watch dog reallocation procedure may temporarily cause the Rx or Tx arbiters to repeatedly
Queue Engine
RR Arbiter
"Queue Arbiter" Rx arbiter Tx Arbiter
RR Arbiter
SAR Rx I/F
WAN Rx I/F
Loop Rx I/F
SAR Tx I/F
WAN Tx I/F
Loop Tx I/F
Watch Dog Re-allocate
uP Re-allocate
Watch Dog Patrol
Advance TxSlot
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RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
service the same interface (SAR, loop or WAN) until reallocation is complete. This could cause potential starvation of one of the remaining interface services. This is caused because the Rx and Tx arbiters continue to cycle even when the watch dog arbiter has "won" the next Queue Engine opportunity. This effectively blocks the next interface selected by the Rx or Tx arbiter from being serviced for that cycle. If multiple ICIs simultaneously time out, the watch dog could cause the same interface to be repeatedly blocked, which could starve the interface. The effect of this behavior is dependent on the activity at the interfaces. A possible worst case scenario would occur if all of the following conditions were present: * * * * Two out of three interfaces (WAN, Loop or SAR) have 2 or more cells in the internal FIFOs waiting to be serviced Frame contiguous queuing of VCs is being used The VC timeout watch dog is enabled (QWwdActive=1) The watch dog patrol is executed and discovers re-assembly time out errors in VCs that have sequential ICIs
Resolution The probability of a re-assembly time out for a sequence of VCs would be very low in normal operations. The most likely worst case scenario would be the simultaneous time out of all VCs associated with a given port due to a catastrophic fault on that port. If the VCs on any given port were mapped to nonsequential ICIs, the Rx and Tx interfaces would have an opportunity to successfully service requests between VC reallocations. Typically there will be a device between the S/UNI Apex and the link layer that can perform an address resolution function (the S/UNI Atlas for example). This device could be also be used to map each VC on a port to non-contiguous ICIs. One possible strategy would be to map VCs on even-numbered ports to evennumbered ICIs and VCs on odd-numbered ports to odd-numbered ICIs. This "striping" would ensure that the VCs associated with any port fault would not occupy contiguous ICIs and would therefore avoid the service arbitration behavior described above.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS' INTERNAL USE
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RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
2.2
Any-PHY Bus, RSX Signal Timing Restriction Document Reference S/UNI-APEX ATM/Packet Manager and Switch Data Sheet: * Section 9.1 * Section 9.3 * Register 0x10 - Hi Priority Interrupt Status * Register 0x14 - High Priority Interrupt Mask Description Note that the behavior described below will only impact you if you are designing a custom Any-PHY slave device to interface to the S/UNI-APEX. This behavior is only significant if the S/UNI-APEX is operating in Any-PHY master mode in the receive direction. The behavior is identical on the loop bus and the WAN bus. This behavior has no impact when the S/UNI-APEX is operating as a Utopia L2 master or Utopia L2 slave. When functioning as an Any-PHY receive master the behavior of the RSX input signal (LRSX for the loop bus, WRSX for the WAN bus) is not precisely as documented in the data sheet. In Section 9.1 (9.3) the data sheet states, "LRSX (WRSX) is asserted by the selected PHY device during the first cycle of a data block transfer coinciding with the port address prepend." To be fully compliant with the Any-PHY specification the S/UNI-APEX should be able to accept the RSX signal being asserted at two or more clock periods after LRENB (WRENB) has been asserted. Indeed, the S/UNI-APEX will successfully accept a cell transfer if RSX is asserted 2 or more clock periods after RENB, however, unless RSX is asserted at exactly 2 clock periods after RENB the S/UNI-APEX will generated an erroneous "Runt cell error interrupt", as defined in Register 0x10 - Hi Priority Interrupt Status. Resolution The behavior described below has no impact when the S/UNI-APEX is connected to PMC-Sierra Any-PHY devices such as the S/UNI-VORTEX and S/UNI-DUPLEX because these slave devices generate RSX exactly two clock periods after RENB. Customers designing their own Any-PHY slave devices should ensure that their device responds to RENB by asserting RSX and initiating the cell transfer in exactly 2 clock periods. Typically, a 2 clock period response time is desirable
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS' INTERNAL USE
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RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
anyway since it provides the maximum bus throughput and is not difficult to achieve. Therefore this should have little or no impact on most designs. If for some reason it is impossible to design your custom device to respond to RSX in 2 clock periods you can still operate the S/UNI-APEX with RSX occurring at 3 or more clock periods after the RENB. In this scenario, the receive cell transfers continue to function correctly, so simply mask out the runt cell interrupt using Register 0x14 and ignore the "runt cell" interrupt bit in Register 0x10.
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RELEASED ERRATA PMC-1991770 ISSUE 1
PM7326 S/UNI-APEX
ATM/PACKET TRAFFIC MANGER AND SWITCH
CONTACTING PMC-SIERRA, INC. PMC-Sierra, Inc. 105-8555 Baxter Place Burnaby, BC Canada V5A 4V7 Tel: Fax: (604) 415-6000 (604) 415-6200 document@pmc-sierra.com info@pmc-sierra.com apps@pmc-sierra.com http://www.pmc-sierra.com
Document Information: Corporate Information: Application Information: Web Site:
None of the information contained in this document constitutes an express or implied warranty by PMC-Sierra, Inc. as to the sufficiency, fitness or suitability for a particular purpose of any such information or the fitness, or suitability for a particular purpose, merchantability, performance, compatibility with other parts or systems, of any of the products of PMC-Sierra, Inc., or any portion thereof, referred to in this document. PMC-Sierra, Inc. expressly disclaims all representations and warranties of any kind regarding the contents or use of the information, including, but not limited to, express and implied warranties of accuracy, completeness, merchantability, fitness for a particular use, or non-infringement. In no event will PMC-Sierra, Inc. be liable for any direct, indirect, special, incidental or consequential damages, including, but not limited to, lost profits, lost business or lost data resulting from any use of or reliance upon the information, whether or not PMC-Sierra, Inc. has been advised of the possibility of such damage. (c) 2000 PMC-Sierra, Inc. PMC-1991770 (R1) ref PMC-981224 (R6), ref PMC-991454 (R2), ref PMC-991727 (P1) Issue date: April 2000
PMC-Sierra, Inc.
105 - 8555 Baxter Place Burnaby, BC Canada V5A 4V7 604 .415.6000

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