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The Arm Ethos-U NPUs have a PMU with performance counters. The PMU h/w supports up to 4 (U65) or 8 (U85) counters which can be programmed for different events. There is also a dedicated cycle counter. The ABI and implementation are copied from the V3D driver. The main difference in the ABI is there is no query API for the event list. The events differ between the U65 and U85, so the events lists are maintained in userspace along with other differences between the U65 and U85. The cycle counter is always enabled when the PMU is enabled. When the user requests N events, reading the counters will return the N events plus the cycle counter. Signed-off-by: Rob Herring (Arm) <robh@kernel.org> Signed-off-by: Tomeu Vizoso <tomeu@tomeuvizoso.net> Reviewed-by: Maíra Canal <mcanal@igalia.com> Link: https://patch.msgid.link/20260601173814.250071-1-tomeu@tomeuvizoso.net --- v2: - Use XArray instead of idr - Rework locking to use per device spinlock to protect modifying active perfmon. Based on pending V3D changes: https://lore.kernel.org/all/20260508-v3d-perfmon-lifetime-v1-1-f5b5642c085f@igalia.com/ - Add missing perfmon puts in ethosu_ioctl_perfmon_set_global() and ethosu_ioctl_perfmon_get_values() error paths. - Fix reading number of counters on U85. - Add defines NPU_REG_PMCCNTR_CFG v3: - Add explicit padding to drm_ethosu_perfmon_destroy - Fix SPDX license expression - Fix comment typos - Convert perfmon lock from spinlock to mutex - Simplify switch_perfmon condition check - Remove unused ethosu_perfmon_init - Add lockdep_assert_held to ethosu_perfmon_stop_locked v4: - Use drmm_mutex_init() for perfmon lock - Add lockdep_assert_held() to ethosu_perfmon_start() - Fix a few style issues reported by Maíra