perf: Add driver for Arm NI-700 interconnect PMU

The Arm NI-700 Network-on-Chip Interconnect has a relatively
straightforward design with a hierarchy of voltage, power, and clock
domains, where each clock domain then contains a number of interface
units and a PMU which can monitor events thereon. As such, it begets a
relatively straightforward driver to interface those PMUs with perf.

Even more so than with arm-cmn, users will require detailed knowledge of
the wider system topology in order to meaningfully analyse anything,
since the interconnect itself cannot know what lies beyond the boundary
of each inscrutably-numbered interface. Given that, for now they are
also expected to refer to the NI-700 documentation for the relevant
event IDs to provide as well. An identifier is implemented so we can
come back and add jevents if anyone really wants to.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/9933058d0ab8138c78a61cd6852ea5d5ff48e393.1725470837.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index aa9530b4064f..bab8ba64162f 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -48,6 +48,13 @@ config ARM_CMN
 	  Support for PMU events monitoring on the Arm CMN-600 Coherent Mesh
 	  Network interconnect.
 
+config ARM_NI
+	tristate "Arm NI-700 PMU support"
+	depends on ARM64 || COMPILE_TEST
+	help
+	  Support for PMU events monitoring on the Arm NI-700 Network-on-Chip
+	  interconnect and family.
+
 config ARM_PMU
 	depends on ARM || ARM64
 	bool "ARM PMU framework"