Group pushes socket for IP plug and play

Group pushes socket for IP plug and play
By Michael Santarini, EE Times
December 6, 2001 (8:06 a.m. EST)
URL: http://www.eetimes.com/story/OEG20011203S0041

SAN MATEO, Calif. — Frustrated by the chip industry's inability to create broadly usable intellectual-property cores, a group of companies is rallying behind a high-level interface that they say goes beyond previous attempts to make disparate blocks of on-chip circuitry work together. The interface layer has already garnered considerable industry support. But there's a chance that it could clash with similar schemes promoted by some influential vendors with a large stake in system-on-chip design.

The Open Core Protocol International Partnership, founded by Sonics Inc., Nokia, United Microelectronics Corp. (UMC), MIPS Technologies Inc. and Texas Instruments Inc., says it intends to take over where the Virtual Socket Interface Alliance's Virtual Component Interface left off. The partnership intends to drive Sonics' more mature Open Core Protocol (OCP) as a standardized socket for plugging cores or virtual components into system-on-chip (SoC) de signs.

The VSIA is endorsing the effort. IP vendors said they, too, would rally behind an open socket standard if the technology indeed went above and beyond the VSIA's VCI and was more widely adopted than the VSIA interface.

Plug-and-play IP has been a goal of the IP industry for years, since it would, in theory, allow SoC designers to connect cores from different IP vendors to rapidly create a system-on-chip.

But the goal has proved difficult to reach because of the proliferation of IP vendors and the myriad buses used throughout the industry. Either IP vendors have had to modify their cores to interface with each bus or SoC designers have had to spend valuable time creating interfaces that allow them to use disparate cores in their designs.

VSIA's VCI was the first run at an open industry standard that would let IP vendors tie their cores to one protocol and then create wrappers for each targeted bus.

But OCP, according to Ian MacIntosh, president of OCP-IP, is far more advanced t han VCI. And like VCI, OCP it is an open standard, whereas such competing on-chip buses as IBM's CoreConnect and ARM's Amba are proprietary.

"Up until now, there hasn't been a viable and complete interface openly available to the entire IC design industry," said MacIntosh. "OCP-IP is an open effort, driven and directed by users who want an open standard that will really make plug and play a reality."

MacIntosh, who chaired the Intellectual Property Protection working group at VSIA, said OCP contains most, if not all, of the best attributes of the combined VSIA VCI standards: PVCI, for peripherals; BVCI, for use with a basic four-input system bus; and Advanced VCI, which adds complex structures for pipelining as well as structures for graphics and burst mode. OCP's advantage over the VCI superset is that it defines core communication requirements not only for the data flow but also for control and test flows, he said.

"There has not been a truly open virtual-component interface standard before th at would have gained wide support in the industry," said Anssi Haverinen, research manager at Nokia and an OCP-IP governing-board member. "The closest equivalent in the open-interface area is VSIA. These efforts are not competing; the OCP-IP is continuing where the VSIA left off after finishing the VCI family standards. VSIA cannot focus on interfaces only; the charter is much larger."

Indeed, the organization has received the blessing of VSIA.

Larry Cooke, vice president of marketing at VSIA, said the OCP effort has all of the components of BVCI and PVCI as well as more advanced features than AVCI, making it compatible with all the VCI specs. "Plus, OCP has added application notes and compliance suites that we don't offer," said Cooke. "So in a way, an OCP member wishing to use VCI could use the compliance suites to verify VCI."

In commercial use, OCP is used by Sonics' MicroNetwork tool to create a wrapper for third-party IP so that the IP can be easily plugged into the Sonics MicroNetwork. T he company claims tapeouts with NEC and Malleable and counts Broadcom and Hughes among its big customers.

"We have worked in the past with Sonics and are familiar with the technology," said Ed Wan, vice president for worldwide field engineering at UMC. "We believe this effort is good for the reuse of IP and in a sense will help us, too. Creating IP is hard enough; making sure [different cores] work together on the same chip is even more difficult. We believe a standard like this will speed plug and play and allow us all to get designs to market faster."

Looking for improvement

IP vendors not yet briefed by OCP-IP on its standards effort said that in general, they would favor and perhaps adopt an open industry-standard interface as long as its functionality exceeded that of VSIA's VCI, which many described as short on substance.

"We've been a proponent of standards-based interfaces from the onset and were instrumental in developing the VCI with VSIA," said a spokesman for core vend or inSilicon Corp. "But to make it an industry standard it must not only be technically better than VCI, but it must also build a critical mass of users. In general we will support anything that builds great demand from our customers."

Dave Wood, product-marketing manager at Mentor Graphics Corp.'s Inventra IP unit, said Mentor, like inSilicon, has targeted all of its IP to VCI and will wait and see whether OCP-IP does indeed offer an improved solution.

"It sounds like an improved version of VCI, so we wouldn't have to change how we develop cores," said Wood. "OCP has a compliance suite, which VCI really lacks. Something like that would really help SoC developers test to make sure their cores will work with their targeted bus. ARM, for example, has compliance tools, but they are targeted for implementation in ARM designs."

In addition to donating OCP to OCP-IP, Sonics is donating its Core Creator, which lets core developers check that their cores comply with the OCP specification.

"The sof tware allows you to validate that the features you implemented in the data, control and test areas comply with protocol," said MacIntosh. "The tool also allows you to judge the efficiency of the interface and see the details of the interface. Nobody else offers a technology that allows users to validate that the protocol is correct."

The Core Creator technology also helps package IP along with test vectors, synthesis scripts and timing constraints.

But MacIntosh said OCP will not be reliant on Sonics' or any other vendor's tools for implementation. He said the organization will consider all donations and member suggestions as well as develop its own tools to aid members in implementing OCP.

"OCP is an open standard," said MacIntosh. "It doesn't tie you to a bus approach, design approach or tool flow. It is also independent and is not tied to any company."

Holy grail?

Tony Massimini, chief of technology at Semico Research Corp. (Phoenix), expects IP vendors to welcome the effo rt warmly. "It's really the holy grail for IP vendors," he said. "They have all been looking for a standard that they can all work with, and this may be it."

Massimini said he is encouraged by the broad support from users backing OCP-IP but said it would be better if the group could get ARM, whose Amba bus is gaining in popularity, to join the effort so that it doesn't clash with that company's compliance program.

An ARM spokesman said the company is aware of the OCP-IP effort but hasn't yet evaluated whether the effort is a threat to ARM's market position.

MacIntosh downplayed the competitive aspects, saying that the targeted bus is a somewhat trivial matter because the OCP interface can connect cores to ARM's Amba, IBM's CoreConnect and other on-chip buses.

But Tom Lowery, manager of the systems-on-silicon development unit at IBM Microelectronics, said that connecting one link to another — for example, OCP to CoreConnect — in general would bog down a chip's timing and add gates to a design. The use of the two links together would not suit the highest-performance designs but would suffice for most other SoC implementations, he said.

Still, OCP is technically better than ARM's Amba AHB and on par with CoreConnect's Onchip Peripheral Bus, said Rick Hoffmann, senior engineer at IBM and architect of CoreConnect.

Yet IBM, the market-leading ASIC supplier, has no plans to drop its work on CoreConnect to join OCP-IP. "I'm not quite sure if this is a marketing scheme from Sonics," said Hoffmann. "It's good technology, and they've proven it on silicon. But they freely licensed OCP before, and now they are trying to make it a standard. If they get this in place as a standard, they certainly will have the opportunity to sell more of their tools and their MicroNetwork."

IBM's CoreConnect is not an open standard per se, but the company does license the bus technology for free over its Web site. IBM claims to have more than 100 CoreConnect licensees, with the potential for greater proliferation via a partnership agreement with Xilinx Inc.

Lowery said his small group controls the spec within IBM. "We've seen that when you get a bunch of different companies sitting on a standards-governing board, it is difficult to get things done quickly because everyone wants to make sure their own company's interests are being served," he said. "We don't have that problem, because we implement all changes. But we get many of our ideas directly from our CoreConnect users."

Three-tiered effort

OCP-IP intends to grow the OCP interface via a three-tiered "community source" effort. The highest tier, the Governing Steering Committee, consists of the founding members of OCP-IP. The committee will have final word on all changes and improvements that are made to the spec.

The second tier will comprise corporate sponsors, which, for a $25,000 annual membership, can participate in working groups, shaping the direction of OCP. The sponsors will also have early access to any improvement s or new versions of the standard when those are released.

Community members, the third tier, get access to the OCP-IP tools and services for a $10,000 annual membership. Membership benefits include eligibility for working groups, access to community-source products and services, and participation in certification "plugfests."

"We have our Governing Steering Committee in place, and now we want to invite all interested parties to join the effort as either sponsor members or community members," said MacIntosh. More information is available at the OCP-IP Web site.

Nokia's Haverinen said he hopes the OCP-IP effort popularizes the VCI methodology. "We hope the end result, if you will, is a living, supported interface standard used by a multitude of companies dealing with SoCs and virtual components."