iMC SMBus controller driver

[Ravi Pokala]

-----Original Message-----
> From: Andriy Gapon <avg at FreeBSD.org>
> Date: 2017-05-19, Friday at 02:21
> To: Ravi Pokala <rpokala at mac.com>, "freebsd-hackers at freebsd.org" <freebsd-hackers at FreeBSD.org>
> Subject: Re: iMC SMBus controller driver
> 
> On 19/05/2017 00:22, Ravi Pokala wrote:
>> Hi folks,
>> 
>> In recent years, Intel has put an SMBus controller on the CPU's integrated Memory Controller (iMC). Does anyone have a driver for that? Even if it's not something that you're willing to open up, just knowing that someone has done it would be nice.
>> 
>> (I'm specifically interested in Haswell/Broadwell Xeon, but I'd imagine the programming model is the same for the iMC/SMBus controller on all the recent CPUs.)
> 
> Could ismt be what you are looking for?

Yes and no. ismt(4) is a non-ichsmb SMBus controller, but the driver only supports Atom S1200 (Briarwood) and Atom C2000 (Avoton / Rangeley) SoCs. But maybe it just needs to have newer devices added to the list...?

As it happens, I have the datasheet for the Rangeley at my fingertips. I searched for some of the magic numbers from ismt(4), and found where the "SMT" SMBus controller (PCI 0:13:0) is documented. I also did some digging on Intel's site, and found Volume 2 of the Broadwell Xeon datasheet, where the iMC (PCI 0:19:0 and 0:22:0) is documented. Unfortunately, Rangeley's SMT SMBus controller and Broadwell's iMC's SMBus controller bear no resemblance to each other.

So, no, ismt(4) is not the droid ^W driver I'm looking for. :-/

Thanks,

Ravi (rpokala@)

> -- 
> Andriy Gapon