[PATCH 0/6] add support for CDX bus

[Nipun Gupta]

On 4/7/2023 12:48 PM, David Marchand wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
> 
> 
> Hello,
> 
> On Fri, Apr 7, 2023 at 8:02 AM Nipun Gupta <nipun.gupta at amd.com> wrote:
>>
>> Support AMD CDX bus, for FPGA based CDX devices. The CDX
>> devices are memory mapped on system bus for embedded CPUs.
>>
>> It uses sysfs interface and the vfio-cdx driver to discover
>> and initialize the CDX devices.
>>
>> The patches are intended for DPDK 23.07 release, and have been sent
>> as an RFC as patches are yet to be merged in Linux.
>>
>> Linux CDX bus patches has been added into linux next:
>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/cdx
>>
>> VFIO patches are also submitted in upstream:
>> https://www.spinics.net/lists/kvm/msg310623.html
> 
> Hard to tell just from this link what the status is.
> Has it been reviewed?
> When are you expecting this to get merged?

The CDX bus code has been merged and VFIO code is under review. Apart 
from this, we will soon have Open source Linux from AMD which has all 
the required patches for CDX in a week or so (I will provide the link 
once that is available).

> 
> 
>>
>> CDX is a Hardware Architecture designed for AMD FPGA devices. It
>> consists of mechanism for interaction between FPGA, Firmware and
>> the APUs (Application CPUs).
>> Firmware resides on RPU (Realtime CPUs) which interacts with
>> the FPGA program manager and the APUs. The RPU provides memory-mapped
>> interface (RPU if) which is used to communicate with APUs.
>>
>> VFIO CDX driver provides the CDX device resources like MMIO and interrupts
>> to map to user-space. DPDK CDX bus uses sysfs interface and the vfio-cdx
>> driver to discover and initialize the CDX devices for user-space
>> applications.
>>
>> RFC patches in DPDK were submitted at:
>> http://patches.dpdk.org/project/dpdk/patch/20230124140746.594066-2-nipun.gupta@amd.com/
>>
>> Changes RFC->v1:
>> - Marked few API's as internal which were not required
>>    to be provided to user.
> 
> Just a quick pass on this series.
> 
> - There is an issue with the exported header rte_bus_cdx.h.
> All the bus specific / driver only parts must be moved to a dedicated
> bus_cdx_driver.h header (which must be listed in driver_sdk_headers).
> 
> - To whom is the rte_cdx_dump symbol intended to? Is this for use by
> user applications?
> If so, the rte_bus_cdx.h can be kept, to export this symbol.
> But otherwise, everything in rte_bus_cdx.h can be moved to bus_cdx_driver.h.
> 
> - Please remove the rte_ prefix for static symbols in *.c.

Agree to this.

Regards,
Nipun

> 
> 
> --
> David Marchand
>