[PATCH v3 1/2] drm/panfrost: Enable cycle counting when perfcnt is enabled

[Adrián Larumbe]

From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>

If we don't do that, we end up with invalid timestamps in the block
headers.

We also need to skip the warning on the cycle counter reference being
other than 0 during device reset, because of perfcnt's lingering ref.

Ideally this would be dealt with by splitting the reset sequence into
pre and post stages, so that a hypothetical panfrost_perfcnt_pre_reset()
would release the cycle counter reference. In the absence thereof, we
just make do.

Fixes: 7786fd108777 ("drm/panfrost: Expose performance counters through unstable ioctls")
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Reviewed-by: Steven Price <steven.price@xxxxxxx>
Signed-off-by: Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/panfrost/panfrost_gpu.c     | 7 +++----
 drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 3 +++
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index 6081b27829e1..5c3fee65c9e3 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -94,11 +94,10 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev)
 		  GPU_IRQ_CLEAN_CACHES_COMPLETED);
 
 	/*
-	 * All in-flight jobs should have released their cycle
-	 * counter references upon reset, but let us make sure
+	 * Even though all in-flight jobs should have released their cycle counter
+	 * references upon reset, perfcnt's might still hang about.
 	 */
-	if (drm_WARN_ON(&pfdev->base, atomic_read(&pfdev->cycle_counter.use_count) != 0))
-		atomic_set(&pfdev->cycle_counter.use_count, 0);
+	atomic_set(&pfdev->cycle_counter.use_count, 0);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
index a9def452d5ef..b26da057a1a0 100644
--- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
+++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
@@ -17,6 +17,7 @@
 #include "panfrost_device.h"
 #include "panfrost_features.h"
 #include "panfrost_gem.h"
+#include "panfrost_gpu.h"
 #include "panfrost_issues.h"
 #include "panfrost_job.h"
 #include "panfrost_mmu.h"
@@ -52,6 +53,7 @@ static void panfrost_perfcnt_hw_disable(struct panfrost_device *pfdev)
 	gpu_write(pfdev, GPU_PRFCNT_TILER_EN, 0);
 
 	if (perfcnt->owns_as_ref) {
+		panfrost_cycle_counter_put(pfdev);
 		panfrost_mmu_as_put(pfdev, perfcnt->mapping->mmu);
 		perfcnt->owns_as_ref = false;
 	}
@@ -84,6 +86,7 @@ static int panfrost_perfcnt_hw_enable(struct panfrost_device *pfdev)
 		return ret;
 
 	perfcnt->owns_as_ref = true;
+	panfrost_cycle_counter_get(pfdev);
 
 	as = ret;
 	cfg = GPU_PERFCNT_CFG_AS(as) |

-- 
2.56.0