bus: arm-ccn: Correct required arguments for XP PMU events

XP can provide events from two sources: watchpoints, observing traffic
on device ports and PMU looking at internal buses.

Unfortunately the sysfs definition of the PMU events was requiring
port number (instead of bus number) and direction (the buses are
unidirectional), as these fields were shared with the watchpoint event.

Although it does not introduce a major problem (port can be used as
bus alias and direction is simply ignored for XP PMU events), it's
better to fix it now, before external tools start depending on this
behaviour.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/Documentation/arm/CCN.txt b/Documentation/arm/CCN.txt
index ffca443a19b4..15cdb7bc57c3 100644
--- a/Documentation/arm/CCN.txt
+++ b/Documentation/arm/CCN.txt
@@ -18,13 +18,17 @@ and config2 fields of the perf_event_attr structure. The "events"
 directory provides configuration templates for all documented
 events, that can be used with perf tool. For example "xp_valid_flit"
 is an equivalent of "type=0x8,event=0x4". Other parameters must be
-explicitly specified. For events originating from device, "node"
-defines its index. All crosspoint events require "xp" (index),
-"port" (device port number) and "vc" (virtual channel ID) and
-"dir" (direction). Watchpoints (special "event" value 0xfe) also
-require comparator values ("cmp_l" and "cmp_h") and "mask", being
-index of the comparator mask.
+explicitly specified.
 
+For events originating from device, "node" defines its index.
+
+Crosspoint PMU events require "xp" (index), "bus" (bus number)
+and "vc" (virtual channel ID).
+
+Crosspoint watchpoint-based events (special "event" value 0xfe)
+require "xp" and "vc" as as above plus "port" (device port index),
+"dir" (transmit/receive direction), comparator values ("cmp_l"
+and "cmp_h") and "mask", being index of the comparator mask.
 Masks are defined separately from the event description
 (due to limited number of the config values) in the "cmp_mask"
 directory, with first 8 configurable by user and additional