PCIe PMU Root Complex Integrated End Point(RCiEP) device is supported
to sample bandwidth, latency, buffer occupation etc.

Each PMU RCiEP device monitors multiple Root Ports, and each RCiEP is
registered as a PMU in /sys/bus/event_source/devices, so users can
select target PMU, and use filter to do further sets.

Filtering options contains:
event     - select the event.
port      - select target Root Ports. Information of Root Ports are
            shown under sysfs.
bdf       - select requester_id of target EP device.
trig_len  - set trigger condition for starting event statistics.
trig_mode - set trigger mode. 0 means starting to statistic when bigger
            than trigger condition, and 1 means smaller.
thr_len   - set threshold for statistics.
thr_mode  - set threshold mode. 0 means count when bigger than threshold,
            and 1 means smaller.
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Qi Liu <liuqi115@huawei.com>
Reviewed-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Link: https://lore.kernel.org/r/20211202080633.2919-3-liuqi115@huawei.comSigned-off-by: Will Deacon <will@kernel.org>