drm/msm/a6xx: Add traces for preemption

Add trace points corresponding to preemption being triggered and being
completed for latency measurement purposes.

Reviewed-by: Akhil P Oommen <[e-mail]>
Tested-by: Rob Clark <[e-mail]>
Tested-by: Neil Armstrong <[e-mail]> # on SM8650-QRD
Tested-by: Neil Armstrong <[e-mail]> # on SM8550-QRD
Tested-by: Neil Armstrong <[e-mail]> # on SM8450-HDK
Signed-off-by: Antonino Maniscalco <[e-mail]>
Patchwork: https://patchwork.freedesktop.org/patch/618026/
Signed-off-by: Rob Clark <[e-mail]>

drivers/gpu/drm/msm/adreno/a6xx_preempt.c

···
 #include "a6xx_gpu.h"
 #include "a6xx_gmu.xml.h"
 #include "msm_mmu.h"
+#include "msm_gpu_trace.h"
 
 /*
  * Try to transition the preemption state from old to new. Return
···
 
 	set_preempt_state(a6xx_gpu, PREEMPT_NONE);
 
+	trace_msm_gpu_preemption_irq(a6xx_gpu->cur_ring->id);
+
 	/*
 	 * Retrigger preemption to avoid a deadlock that might occur when preemption
 	 * is skipped due to it being already in flight when requested.
···
 	 * to be atomic.
 	 */
 	ring->restore_wptr = false;
+
+	trace_msm_gpu_preemption_trigger(a6xx_gpu->cur_ring->id,
+		ring ? ring->id : -1);
 
 	spin_unlock_irqrestore(&ring->preempt_lock, flags);
 

drivers/gpu/drm/msm/msm_gpu_trace.h

···
 		TP_printk("%u", __entry->dummy)
 );
 
+TRACE_EVENT(msm_gpu_preemption_trigger,
+		TP_PROTO(int ring_id_from, int ring_id_to),
+		TP_ARGS(ring_id_from, ring_id_to),
+		TP_STRUCT__entry(
+			__field(int, ring_id_from)
+			__field(int, ring_id_to)
+			),
+		TP_fast_assign(
+			__entry->ring_id_from = ring_id_from;
+			__entry->ring_id_to = ring_id_to;
+			),
+		TP_printk("preempting %u -> %u",
+			  __entry->ring_id_from,
+			  __entry->ring_id_to)
+);
+
+TRACE_EVENT(msm_gpu_preemption_irq,
+		TP_PROTO(u32 ring_id),
+		TP_ARGS(ring_id),
+		TP_STRUCT__entry(
+			__field(u32, ring_id)
+			),
+		TP_fast_assign(
+			__entry->ring_id = ring_id;
+			),
+		TP_printk("preempted to %u", __entry->ring_id)
+);
+
 #endif
 
 #undef TRACE_INCLUDE_PATH