Users of SBE FIFO kernel driver

[Venkatesh Sainath]

On 10/02/17 2:46 AM, Patrick Williams wrote:
> On Sat, Feb 04, 2017 at 04:35:30PM +0530, Venkatesh Sainath wrote:
>>> Where do we stand with the sbei protocol device driver?  Who owns this
>>> and is it complete?
>>>
>> The plan was to port the sbei protocol driver developed on FSP based
>> systems. Chris: I believe Dhruvaraj discussed with you about this driver
>> when he was in Austin. I can share the latest version of this driver.
> Is this "driver" really a driver in the Linux sense or is it a shared
> library that is used in FSP userspace?  Whatever code we end up using we
> eventually need it to be upstream-able into the real Linux kernel.
This is not really a driver in the Linux sense. It is a shared lib in 
FSP user space. As the OCC driver has to use this SBEI protocol, we  
have to implement this as a Linux driver in OpenBMC
> Is this something that Dhruv can take on or is this going to be left to
> Chris?  How do we handle divergence between the open-source code and the
> IBM proprietary version (the one direction is an IBM-internal problem,
> but I have concern that future development will only be happening on
> the proprietary one and we'll have to keep playing catch up).
>
The SBE interfaces are open-sourced and there may not be any proprietary 
implementation here. However, the code architecture between FSP and 
OpenBMC is different ( FSP - user space and OpenBMC - Linux driver ) and 
hence we will have to maintain two streams. The HWSV team can implement  
it as a Linux driver in OpenBMC and deliver it in stages. Any defect 
fixes in future can be done by the same team on both streams. I will ask 
Sachin Gupta to sync up with Chris. As of now, we need only Get/Put 
Memory, Get/Put Scom and Get/Put SRAM for enabling OCC and HW access. We 
can add the remaining interfaces subsequently. As a user of this SBEI 
protocol driver, we need OCC driver changes, Rest API to call OCC 
driver, SCOM drivers and user space app (Rest API / ??) to call the SCOM 
driver.