Re: [RFC PATCH 0/2] cxl: Add support for disabling CAPP when unloading CXL

[Frederic Barrat <fbarrat@linux.ibm.com>]

Hi Vaibhav,

I think there's value in there, as I'm hearing Mellanox would prefer to 
start from a "clean" state, as in pci mode, when they load their driver 
after a card FW update.

However, I'm pretty reluctant to make it the default behaviour. It's not 
like we haven't had our share of problems on reset before :-) 
Furthermore, for non-mlx5 case, we don't really have a reason for this.
I'm thinking we could activate it through a per-adapter property, on 
/sys. See comment in one of the patches.

   Fred


Le 25/01/2019 à 06:11, Vaibhav Jain a écrit :
> Recent updates to OPAL have implemented necessary infrastructure [1] to disable
> CAPP and switch PHB back to PCIE mode during fast reset. This small patch-set
> uses the same OPAL infrastructure to force disable of CAPP when CXL module is
> unloaded via rmmod.
> 
> References:
> [1]: https://lists.ozlabs.org/pipermail/skiboot/2019-January/013063.html
> 
> Vaibhav Jain (2):
>    powerpc/powernv: Add support for CXL mode switch that need PHB reset
>    cxl: Force a CAPP reset when unloading CXL module
> 
>   arch/powerpc/platforms/powernv/pci-cxl.c | 71 +++++++++++++++++++++---
>   drivers/misc/cxl/cxl.h                   |  1 +
>   drivers/misc/cxl/main.c                  |  3 +
>   drivers/misc/cxl/pci.c                   | 25 ++++++++-
>   4 files changed, 91 insertions(+), 9 deletions(-)
>