AXI performance monitor driver (#2222)

Uses the debugfs I/F to provide access to the AXI
bus performance monitors.

Requires the new mailbox peripheral access for access
to the VPU performance registers, system bus access
is done using direct register reads.

Signed-off-by: James Hughes <[email protected]>

Author: JamesH65

drivers/perf/Kconfig

@@ -102,4 +102,11 @@ config ARM_SPE_PMU
 	  Extension, which provides periodic sampling of operations in
 	  the CPU pipeline and reports this via the perf AUX interface.
 
+config RPI_AXIPERF
+        depends on ARCH_BCM2835
+        tristate "RaspberryPi AXI Performance monitors"
+        default n
+        help
+          Say y if you want to use Raspberry Pi AXI performance monitors, m if
+          you want to build it as a module.
 endmenu

drivers/perf/Makefile

@@ -9,3 +9,4 @@ obj-$(CONFIG_QCOM_L2_PMU)	+= qcom_l2_pmu.o
 obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
 obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
 obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
+obj-$(CONFIG_RPI_AXIPERF) += raspberrypi_axi_monitor.o