This argument used to come up when I worked at Cambridge Silicon Radio, where we made ASICs. We made our own CPU designs for those ASICs.

Some of the engineers thought making our own CPU designs was a stupid idea and some thought that switching to ARM designs was a stupid idea. The only fact I have is that our CPU designs were not the main cause of bugs in our chips. If you asked the digital designers, they'd say things like, "Why are software engineers so interested in CPU designs. The kinds of embedded CPUs we need are easy to design. Implementing a correct power management state machine is hard. Implementing an efficient WiFi PHY is hard. Get off my lawn..."

Some problems with putting ARM CPUs in our chips were: a) integration engineering costs (ie find a way to multiplex some existing pins on the package with the jtag debug port), b) having to do price and contract negotiation with ARM (that part of the company was less efficient than the digital engineering team), c) finding that the change you wanted to make to the chip was incompatible with the ARM contract you'd just spent 6 months negotiating.

But you also left developers with really hard to use dev tools based on a fork of gcc. The arch also left you having to do all kinds of mental gymnastics when writing code to make sure you were keeping the size down.

That said the chips certainly did there job at a good price point once you got everything stable and fixes made to the binary blobs that you had no way to debug.

> But you also left developers with really hard to use dev tools based on a fork of gcc

Yep. Sorry about that. Not that it was my fault. Anyhow, I guess my belief is that a similar company to CSR could put RISCV cores in their chips now, which would avoid the problem you describe and some of the problems I described with using ARM.

Ah, the good old XAP processor. For a while you guys were marketing a BC03 or BC04 era chip as a general-purpose microcontroller with digital audio functions.

I believe CSR went out of business after burning an investment of $1bn with nothing to show for.

Not trying to be hostile, just pointing out how costly "let's design our own soc, how hard can it be?" is.

Are we talking about same CSR? It’s still in business. It’s now part of Qualcomm: https://en.m.wikipedia.org/wiki/CSR_(company)

Hmmm.. I stand corrected.

I know a few people who joined ARM after CSR closed down but that could be just some offices shutting down.

(not an arm employee, btw)

The offices in Cambridge didn't shutdown. Approximately Samsung bought one building (WiFi), and a year later Qualcomm bought the other (BT + audio). Both Samsung and Qualcomm had rounds of redundancies but have also both hired lots of people. My guess is both offices are about the same fullness as they were ten years ago.

1.5% of your per unit revenue for a hard drive seems significant. WD seems to agree, and they don't seem like a risk prone company.

1.5% does sound significant, but does WD save 100% of those 1.5% by doing it in-house?

Furthermore, those 1.5% covered more than just the CPU (peripherals, buss technologies, patents, manufacturing know-how).

I'm not saying WD is wrong, but I think they are overestimating how much they can save. This is probably just to get a better deal from arm.

1.5% of a big number is still a big number. Western Digital's revenue in 2018 was 18 billion. Even if only 0.15% of their revenue went to ARM, that would be 27M or enough to hire 100 chip designers at 270K each.

That would be enough people for a very advanced chip, but WD doesn't need to build the next supercomputer. Instead, they want a chip customized to handle their specific workload with high throughput and probably some specialized instructions to put some algorithms in hardware. Moreover, their RISCV chip design expense should reduce over time both because they don't need to change chip micro-architectures very often and because as more companies switch to shared, open hardware, the costs are reduced

Another example is Nvidia. They continue to hold an ARM license for several ARM designs and another license for their own custom Denver/Carmel designs. Despite this, they still opted to use RISCV in their GPUs.

These companies manufacture chip designs for a living. They certainly understand the costs involved and have determined the immediate and long-term costs are lower vs the provided benefits.

From their public statements, this is not to get a better deal from ARM. they are all-in with risc-v and have already made public their first core (among other things), which is better than an equivalent from ARM. At this point I dont think ARM could bring much to the table for WD. They've invested way beyond what makes sense for getting better pricing.

It's not for the whole unit, just the chip? Isn't it Qualcomm with the whole-device royalties?

Seems you may be right, but how would you calculate the "chip selling price" for a chip inside a hard drive? It's not clear to me what the royalty charge is for a company like WD.

Probably they've negotiated a nominal value with their ARM rep based on whatever they're currently using.

> One round of asic that fails is significantly more expensive.

Does that change with ARM? If you're licensing the ISA, or even bits of HDL, you're still fabbing your own stuff, right?

If it was the choice between pre-made RISCV and pre-made ARM, then the licensing could play into a cost difference between models, but otherwise they'd both be pre-fabbed, ready-to-use-products?

But then why bother if you are just using someone elses pre-made macros with a fixed architecture (cpu + memories + peripherals + power & clock distribution)? At this stage, would it even be cheaper?

I think there is some merit to risc-v but people pushing hard for it's use RIGHT NOW don't seem to understand the challenges of SoC design and manufacturing.