  Throughout the last decade, the Advanced Telecommunications Computing
Architecture (ATCA) solidified its position as one of the main switched-based
crate standards for advanced Physics instrumentation, offering not only highly
performant characteristics in data throughput, channel density or power
supply/dissipation capabilities, but also special features for high
availability (HA), required for latest and upcoming large-scale endeavours, as
is the case of ITER. Hot Swap is one of the main HA features in ATCA, allowing
for Boards to be replaced in a crate (Shelf), without powering off the whole
system. Platforms using the Peripheral Component Interconnect Express (PCIe)
protocol on the Fabric Interface must be complemented, at the software level,
with the PCIe Hot Plug native feature, currently not specified for the ATCA
form-factor. From a customised Hot Plug support implementation for ATCA Node
Boards, the paper presents an implementation extension for Hub Boards, allowing
Hot Plug of PCIe switching devices, without causing bus enumeration problems.
This paper further addresses the main issues concerning an eventual
standardization of PCIe Hot Plug support in ATCA, such as the implementability
of Hot Plug Elements and the generation and management of Hot Plug Events,
aiming to stimulate the discussion within the PICMG community towards a long
overdue standardized solution for Hot Plug in ATCA.
