MCTP over PCI on AST2500

[Deepak Kodihalli]

On 13/01/20 10:23 PM, Khetan, Sharad wrote:
> Hi Andrew,
> 
> On Thu, 9 Jan 2020, at 12:27, Andrew Jeffery wrote:
>>
>>
>> On Sat, 21 Dec 2019, at 10:45, Khetan, Sharad wrote:
>>> Hi Andrew,
>>> Sorry for late response.
>>> The plan is to have MCTP in user space.
>>>
>>
>> How are you handling this then? mmap()'ing the BAR from sysfs?
> 
>> Sorry, let me put my brain back in, I was thinking of the wrong side of the  BMC/Host MCTP channel. How much were you planning to do in userspace on the BMC? As in, are you planning to drive the BMC's PCIe MCTP controller from userspace (presumably via /dev/mem)?
> 
>   
> For implementation on the BMC, we agree that it's better to do it in kernel (and as you mentioned  - use consistent interface to upper layers, provide another transport). However, given the time needed to implement things in kernel (and the review after), we are starting with a short term solution. We will be implementing MCTP (protocol elements) in user space, along with a low level MCTP PCIe driver just to push bits on PCIe. Iwona is working on this and should be able to describe the exact primitive.

Do you plan to do the user-space work as an extension to/reusing 
components from openbmc/libmctp?

Thanks,
Deepak