[PATCH v4 05/14] drm/panthor: Keep interrupts masked until they are needed

[Boris Brezillon]

The autogenerated panthor_request_xx_irq() helpers unmask Mali
interrupts before we're sure we'll have a handler registered. For
non-shared IRQ lines, that's fine, but for shared ones, it might cause
an interrupt flood if the HW block raises an interrupt for any reason.

We could reworking the calls in panthor_request_xx_irq(), but it's just
simpler to let the caller decide when they are ready to handle interrupts
and call panthor_pwr_irq_resume() themselves. While at it, rework the
prototype to let users call panthor_pwr_irq_enable_events() explicitly
instead of passing an initial mask to panthor_request_pwr_irq().

Fixes: 5fe909cae118 ("drm/panthor: Add the device logical block")
Reported-by: Shashiko <sashiko-bot@xxxxxxxxxx>
Closes: https://sashiko.dev/#/patchset/20260623-panthor-signal-from-irq-v3-0-2ece396f8ee0@xxxxxxxxxxxxx?part=3
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/panthor/panthor_device.h | 6 +++---
 drivers/gpu/drm/panthor/panthor_fw.c     | 2 +-
 drivers/gpu/drm/panthor/panthor_gpu.c    | 3 ++-
 drivers/gpu/drm/panthor/panthor_mmu.c    | 9 +++++++--
 drivers/gpu/drm/panthor/panthor_pwr.c    | 7 ++++---
 5 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
index 35679bfa1f3a..cf209718096f 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -584,14 +584,14 @@ static inline void panthor_ ## __name ## _irq_resume(struct panthor_irq *pirq)
 												\
 static int panthor_request_ ## __name ## _irq(struct panthor_device *ptdev,			\
 					      struct panthor_irq *pirq,				\
-					      int irq, u32 mask, void __iomem *iomem)		\
+					      int irq, void __iomem *iomem)			\
 {												\
 	pirq->ptdev = ptdev;									\
 	pirq->irq = irq;									\
-	pirq->mask = mask;									\
+	pirq->mask = 0;										\
 	pirq->iomem = iomem;									\
 	spin_lock_init(&pirq->mask_lock);							\
-	panthor_ ## __name ## _irq_resume(pirq);						\
+	gpu_write(pirq->iomem, INT_MASK, 0);							\
 												\
 	return devm_request_threaded_irq(ptdev->base.dev, irq,					\
 					 panthor_ ## __name ## _irq_raw_handler,		\
diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
index 4fbddb9e18c8..de8e6689a869 100644
--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -1474,7 +1474,7 @@ int panthor_fw_init(struct panthor_device *ptdev)
 	if (irq <= 0)
 		return -ENODEV;
 
-	ret = panthor_request_job_irq(ptdev, &fw->irq, irq, 0,
+	ret = panthor_request_job_irq(ptdev, &fw->irq, irq,
 				      ptdev->iomem + JOB_INT_BASE);
 	if (ret) {
 		drm_err(&ptdev->base, "failed to request job irq");
diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c
index e52c5675981f..c013d6bf9a59 100644
--- a/drivers/gpu/drm/panthor/panthor_gpu.c
+++ b/drivers/gpu/drm/panthor/panthor_gpu.c
@@ -170,11 +170,12 @@ int panthor_gpu_init(struct panthor_device *ptdev)
 		return irq;
 
 	ret = panthor_request_gpu_irq(ptdev, &ptdev->gpu->irq, irq,
-				      GPU_INTERRUPTS_MASK,
 				      ptdev->iomem + GPU_INT_BASE);
 	if (ret)
 		return ret;
 
+	panthor_gpu_irq_enable_events(&ptdev->gpu->irq, GPU_INTERRUPTS_MASK);
+	panthor_gpu_irq_resume(&ptdev->gpu->irq);
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index 31cc57029c12..1fef3c5c1b50 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -3406,7 +3406,6 @@ int panthor_mmu_init(struct panthor_device *ptdev)
 		return -ENODEV;
 
 	ret = panthor_request_mmu_irq(ptdev, &mmu->irq, irq,
-				      panthor_mmu_fault_mask(ptdev, ~0),
 				      ptdev->iomem + MMU_INT_BASE);
 	if (ret)
 		return ret;
@@ -3424,7 +3423,13 @@ int panthor_mmu_init(struct panthor_device *ptdev)
 		ptdev->gpu_info.mmu_features |= BITS_PER_LONG;
 	}
 
-	return drmm_add_action_or_reset(&ptdev->base, panthor_mmu_release_wq, mmu->vm.wq);
+	ret = drmm_add_action_or_reset(&ptdev->base, panthor_mmu_release_wq, mmu->vm.wq);
+	if (ret)
+		return ret;
+
+	panthor_mmu_irq_enable_events(&mmu->irq, panthor_mmu_fault_mask(ptdev, ~0));
+	panthor_mmu_irq_resume(&mmu->irq);
+	return 0;
 }
 
 #ifdef CONFIG_DEBUG_FS
diff --git a/drivers/gpu/drm/panthor/panthor_pwr.c b/drivers/gpu/drm/panthor/panthor_pwr.c
index 090362bd700b..f2c2c3000590 100644
--- a/drivers/gpu/drm/panthor/panthor_pwr.c
+++ b/drivers/gpu/drm/panthor/panthor_pwr.c
@@ -484,12 +484,13 @@ int panthor_pwr_init(struct panthor_device *ptdev)
 	if (irq < 0)
 		return irq;
 
-	err = panthor_request_pwr_irq(
-		ptdev, &pwr->irq, irq, PWR_INTERRUPTS_MASK,
-		pwr->iomem + PWR_INT_BASE);
+	err = panthor_request_pwr_irq(ptdev, &pwr->irq, irq,
+				      pwr->iomem + PWR_INT_BASE);
 	if (err)
 		return err;
 
+	panthor_pwr_irq_enable_events(&pwr->irq, PWR_INTERRUPTS_MASK);
+	panthor_pwr_irq_resume(&pwr->irq);
 	return 0;
 }
 

-- 
2.54.0