This series adds two tracepoints to panthor. The first tracepoint allows for inspecting the power status of the hardware subdivisions, e.g. how many shader cores are powered on. This is done by reading three hardware registers when a certain IRQ fires.
The second tracepoint instruments panthor's job IRQ handler. This is more useful than the generic interrupt tracing functionality, as the tracepoint has the events bit mask included, which indicates which command stream group interfaces triggered the interrupt. To test the tracepoints, the following can be used: :~# echo 1 > /sys/kernel/tracing/events/panthor/gpu_power_status/enable :~# echo 1 > /sys/kernel/tracing/events/panthor/gpu_job_irq/enable :~# echo 1 > /sys/kernel/tracing/tracing_on :~# cat /sys/kernel/tracing/trace_pipe Signed-off-by: Nicolas Frattaroli <[email protected]> --- Changes in v10: - Start processing phase in raw_irq_handler (Boris) - enable/disable_events: Only write mask contents in ACTIVE state (Boris) - Elaborate on what mask_lock protects in comment (Boris) - nb: checkpatch reports unnecessary line continuations in the macros at the end of the comment blocks. These warnings are false-positives, the line continuations are necessary. - Link to v9: https://lore.kernel.org/r/[email protected] Changes in v9: - Rebase onto drm-tip 2026y-01m-14d-17h-09m-04s - Move the mask to pirq->mask change in the suspended refactor patch to the follow-up patch - Move the INT_MASK restoration changes in the suspended refactor patch to the follow-up patch - Move panthor_irq::mask_lock member right below the mask member - panthor/mmu: Remove the enable_events calls before resume, as they're redundant - panthor/mmu: Rework the AS fault clearing logic. Drop the spurious disable_events in panthor_vm_active, but use disable_events/enable_events in as_disable/as_enable respectively. This requires doing a forward declaration of the panthor_mmu_irq_handler to get a definition of the helpers before it itself is defined. This works out great, because it means I also no longer have to move the entire panthor_vm_active function down some. - Drop an accidentally added redundant empty line - Link to v8: https://lore.kernel.org/r/[email protected] Changes in v8: - Reorder panthor_irq::state patch to be before the new mask modification helpers. The full set of states was kept (rather than just active/suspended) as they don't hurt and make the follow-up patch more concise in scope. - Also bail out on STATE_SUSPENDING in irq_raw_handler - Job irq: initialize start to 0 and don't emit a tracepoint if it is 0, to fix passing an uninitialised stack variable to userspace if the tracepoint was enabled while the handler was running - Link to v7: https://lore.kernel.org/r/[email protected] Changes in v7: - Get rid of old resume IRQ helper by reworking code throughout panthor, and make what used to be resume_restore in v6 the new resume. - Rename mask_enable/mask_disable to enable_events/disable_events. - Turn panthor_irq::suspended into a multi-state value, and utilise it in the IRQ helpers as appropriate. - Link to v6: https://lore.kernel.org/r/[email protected] Changes in v6: - Read the mask member into a local while holding the lock in irq_threaded_handler. - Drop the lock before entering the while loop, letting the threaded handler function run without holding a spinlock - Re-acquire the spinlock at the end of irq_threaded_handler, OR'ing the mask register's contents with the mask local ANDed by the member. This avoids stomping over any other modified bits, or restoring ones that have been disabled in the meantime. - Link to v5: https://lore.kernel.org/r/[email protected] Changes in v5: - Change the panthor IRQ helpers to guard the mask member and register with a spinlock. The rationale behind using a spinlock, rather than some constellation of atomics, is that we have to guarantee mutual exclusion for state beyond just a single value, namely both the register write, and writes to/reads from the mask member, including reads-from-member-writes-to-register. Making the mask atomic does not do anything to avoid concurrency issues in such a case. - Change the IRQ mask member to not get zeroed when suspended. It's possible something outside of the IRQ helpers depends on this behaviour, but I'd argue the code should not access the mask outside of the IRQ helpers, as it'll do so with no lock taken. - Drop the mask_set function, but add mask_enable/mask_disable helpers to enable/disable individual parts of the IRQ mask. - Add a resume_restore IRQ helper that does the same thing as resume, but does not overwrite the mask member. This avoids me having to refactor whatever panthor_mmu.c is doing with that poor mask member. - Link to v4: https://lore.kernel.org/r/[email protected] Changes in v4: - Include "panthor_hw.h" in panthor_trace.h instead of duplicating the reg/unreg function prototypes. - Link to v3: https://lore.kernel.org/r/[email protected] Changes in v3: - Drop PWRFEATURES patch, as this register is no longer needed by this series. - Eliminate the rt_on field from the gpu_power_status register, as per Steven Price's feedback. - Make gpu_power_status tracepoint reg/unreg functions generic across hardware generations by wrapping a hw op in panthor_hw.c. - Reimplement the <= v13 IRQ mask modification functions as the new hw ops functions. v14 can add its own ops in due time. - Link to v2: https://lore.kernel.org/r/[email protected] Changes in v2: - Only enable the GPU_IRQ_POWER_CHANGED_* IRQ mask bits when the tracepoint is enabled. Necessitates the new irq helper patch. - Only enable the GPU_IRQ_POWER_CHANGED_* IRQ mask bits if the hardware architecture is <= v13, as v14 changes things. - Use _READY instead of _PWRACTIVE registers, and rename the tracepoint accordingly. - Also read the status of the ray tracing unit's power. This is a global flag for all shader cores, it seems. Necessitates the new register definition patch. - Move the POWER_CHANGED_* check to earlier in the interrupt handler. - Also listen to POWER_CHANGED, not just POWER_CHANGED_ALL, as this provides useful information with the _READY registers. - Print the device name in both tracepoints, to disambiguate things on systems with multiple Mali GPUs. - Document the gpu_power_status tracepoint, so the meaning of the fields is made clear. - Link to v1: https://lore.kernel.org/r/[email protected] --- Nicolas Frattaroli (4): drm/panthor: Rework panthor_irq::suspended into panthor_irq::state drm/panthor: Extend IRQ helpers for mask modification/restoration drm/panthor: Add tracepoint for hardware utilisation changes drm/panthor: Add gpu_job_irq tracepoint drivers/gpu/drm/panthor/panthor_device.h | 107 ++++++++++++++++++++++++++----- drivers/gpu/drm/panthor/panthor_fw.c | 16 ++++- drivers/gpu/drm/panthor/panthor_gpu.c | 30 ++++++++- drivers/gpu/drm/panthor/panthor_gpu.h | 2 + drivers/gpu/drm/panthor/panthor_hw.c | 62 ++++++++++++++++++ drivers/gpu/drm/panthor/panthor_hw.h | 8 +++ drivers/gpu/drm/panthor/panthor_mmu.c | 47 +++++++------- drivers/gpu/drm/panthor/panthor_pwr.c | 2 +- drivers/gpu/drm/panthor/panthor_trace.h | 86 +++++++++++++++++++++++++ 9 files changed, 318 insertions(+), 42 deletions(-) --- base-commit: 733664f1edf3c01cc68e6dd0bbdb135158a98a1d change-id: 20251203-panthor-tracepoints-488af09d46e7 Best regards, -- Nicolas Frattaroli <[email protected]>
