perf: Add Arm CMN-600 PMU driver

=============================

Arm Coherent Mesh Network PMU

=============================

CMN-600 is a configurable mesh interconnect consisting of a rectangular

grid of crosspoints (XPs), with each crosspoint supporting up to two

device ports to which various AMBA CHI agents are attached.

CMN implements a distributed PMU design as part of its debug and trace

functionality. This consists of a local monitor (DTM) at every XP, which

counts up to 4 event signals from the connected device nodes and/or the

XP itself. Overflow from these local counters is accumulated in up to 8

global counters implemented by the main controller (DTC), which provides

overall PMU control and interrupts for global counter overflow.

PMU events

----------

The PMU driver registers a single PMU device for the whole interconnect,

see /sys/bus/event_source/devices/arm_cmn. Multi-chip systems may link

more than one CMN together via external CCIX links - in this situation,

each mesh counts its own events entirely independently, and additional

PMU devices will be named arm_cmn_{1..n}.

Most events are specified in a format based directly on the TRM

definitions - "type" selects the respective node type, and "eventid" the

event number. Some events require an additional occupancy ID, which is

specified by "occupid".

* Since RN-D nodes do not have any distinct events from RN-I nodes, they

  are treated as the same type (0xa), and the common event templates are

  named "rnid_*".

* The cycle counter is treated as a synthetic event belonging to the DTC

  node ("type" == 0x3, "eventid" is ignored).

* XP events also encode the port and channel in the "eventid" field, to

  match the underlying pmu_event0_id encoding for the pmu_event_sel

  register. The event templates are named with prefixes to cover all

  permutations.

By default each event provides an aggregate count over all nodes of the

given type. To target a specific node, "bynodeid" must be set to 1 and

"nodeid" to the appropriate value derived from the CMN configuration

(as defined in the "Node ID Mapping" section of the TRM).

Watchpoints

-----------

The PMU can also count watchpoint events to monitor specific flit

traffic. Watchpoints are treated as a synthetic event type, and like PMU

events can be global or targeted with a particular XP's "nodeid" value.

Since the watchpoint direction is otherwise implicit in the underlying

register selection, separate events are provided for flit uploads and

downloads.

The flit match value and mask are passed in config1 and config2 ("val"

and "mask" respectively). "wp_dev_sel", "wp_chn_sel", "wp_grp" and

"wp_exclusive" are specified per the TRM definitions for dtm_wp_config0.

Where a watchpoint needs to match fields from both match groups on the

REQ or SNP channel, it can be specified as two events - one for each

group - with the same nonzero "combine" value. The count for such a

pair of combined events will be attributed to the primary match.

Watchpoint events with a "combine" value of 0 are considered independent

and will count individually.

   qcom_l2_pmu

   qcom_l3_pmu

   arm-ccn

   arm-cmn

   xgene-pmu

   arm_dsu_pmu

   thunderx2-pmu

	  PMU (perf) driver supporting the ARM CCN (Cache Coherent Network)

	  interconnect.

config ARM_CMN

	tristate "Arm CMN-600 PMU support"

	depends on ARM64 || (COMPILE_TEST && 64BIT)

	help

	  Support for PMU events monitoring on the Arm CMN-600 Coherent Mesh

	  Network interconnect.

config ARM_PMU

	depends on ARM || ARM64

	bool "ARM PMU framework"

# SPDX-License-Identifier: GPL-2.0

obj-$(CONFIG_ARM_CCI_PMU) += arm-cci.o

obj-$(CONFIG_ARM_CCN) += arm-ccn.o

obj-$(CONFIG_ARM_CMN) += arm-cmn.o

obj-$(CONFIG_ARM_DSU_PMU) += arm_dsu_pmu.o

obj-$(CONFIG_ARM_PMU) += arm_pmu.o arm_pmu_platform.o

obj-$(CONFIG_ARM_PMU_ACPI) += arm_pmu_acpi.o