1 =============================
2 Arm Coherent Mesh Network PMU
3 =============================
4
5 CMN-600 is a configurable mesh interconnect co
6 grid of crosspoints (XPs), with each crosspoin
7 device ports to which various AMBA CHI agents
8
9 CMN implements a distributed PMU design as par
10 functionality. This consists of a local monito
11 counts up to 4 event signals from the connecte
12 XP itself. Overflow from these local counters
13 global counters implemented by the main contro
14 overall PMU control and interrupts for global
15
16 PMU events
17 ----------
18
19 The PMU driver registers a single PMU device f
20 see /sys/bus/event_source/devices/arm_cmn_0. M
21 more than one CMN together via external CCIX l
22 each mesh counts its own events entirely indep
23 PMU devices will be named arm_cmn_{1..n}.
24
25 Most events are specified in a format based di
26 definitions - "type" selects the respective no
27 event number. Some events require an additiona
28 specified by "occupid".
29
30 * Since RN-D nodes do not have any distinct ev
31 are treated as the same type (0xa), and the
32 named "rnid_*".
33
34 * The cycle counter is treated as a synthetic
35 node ("type" == 0x3, "eventid" is ignored).
36
37 * XP events also encode the port and channel i
38 match the underlying pmu_event0_id encoding
39 register. The event templates are named with
40 permutations.
41
42 By default each event provides an aggregate co
43 given type. To target a specific node, "bynode
44 "nodeid" to the appropriate value derived from
45 (as defined in the "Node ID Mapping" section o
46
47 Watchpoints
48 -----------
49
50 The PMU can also count watchpoint events to mo
51 traffic. Watchpoints are treated as a syntheti
52 events can be global or targeted with a partic
53 Since the watchpoint direction is otherwise im
54 register selection, separate events are provid
55 downloads.
56
57 The flit match value and mask are passed in co
58 and "mask" respectively). "wp_dev_sel", "wp_ch
59 "wp_exclusive" are specified per the TRM defin
60 Where a watchpoint needs to match fields from
61 REQ or SNP channel, it can be specified as two
62 group - with the same nonzero "combine" value.
63 pair of combined events will be attributed to
64 Watchpoint events with a "combine" value of 0
65 and will count individually.
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