[PATCH v2 3/3] drm/panfrost: Synchronize and disable interrupts before powering off
From: AngeloGioacchino Del Regno
Date: Tue Nov 28 2023 - 07:45:29 EST
To make sure that we don't unintentionally perform any unclocked and/or
unpowered R/W operation on GPU registers, before turning off clocks and
regulators we must make sure that no GPU, JOB or MMU ISR execution is
pending: doing that required to add a mechanism to synchronize the
interrupts on suspend.
Add functions panfrost_{gpu,job,mmu}_suspend_irq() which will perform
interrupts masking and ISR execution synchronization, and then call
those in the panfrost_device_runtime_suspend() handler in the exact
sequence of job (may require mmu!) -> mmu -> gpu.
As a side note, JOB and MMU suspend_irq functions needed some special
treatment: as their interrupt handlers will unmask interrupts, it was
necessary to add a bitmap for "is_suspending" which is used to address
the possible corner case of unintentional IRQ unmasking because of ISR
execution after a call to synchronize_irq().
Of course, unmasking the interrupts is being done as part of the reset
happening during runtime_resume(): since we're anyway resuming all of
GPU, JOB, MMU, the only additional action is to zero out the newly
introduced `is_suspending` bitmap directly in the resume handler, as
to avoid adding panfrost_{job,mmu}_resume_irq() function just for
clearing own bits, especially because it currently makes way more sense
to just zero out the bitmap.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
drivers/gpu/drm/panfrost/panfrost_device.c | 4 ++++
drivers/gpu/drm/panfrost/panfrost_device.h | 7 +++++++
drivers/gpu/drm/panfrost/panfrost_gpu.c | 7 +++++++
drivers/gpu/drm/panfrost/panfrost_gpu.h | 1 +
drivers/gpu/drm/panfrost/panfrost_job.c | 18 +++++++++++++++---
drivers/gpu/drm/panfrost/panfrost_job.h | 1 +
drivers/gpu/drm/panfrost/panfrost_mmu.c | 17 ++++++++++++++---
drivers/gpu/drm/panfrost/panfrost_mmu.h | 1 +
8 files changed, 50 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
index c90ad5ee34e7..ed34aa55a7da 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.c
+++ b/drivers/gpu/drm/panfrost/panfrost_device.c
@@ -407,6 +407,7 @@ static int panfrost_device_runtime_resume(struct device *dev)
{
struct panfrost_device *pfdev = dev_get_drvdata(dev);
+ bitmap_zero(pfdev->is_suspending, PANFROST_COMP_BIT_MAX);
panfrost_device_reset(pfdev);
panfrost_devfreq_resume(pfdev);
@@ -421,6 +422,9 @@ static int panfrost_device_runtime_suspend(struct device *dev)
return -EBUSY;
panfrost_devfreq_suspend(pfdev);
+ panfrost_job_suspend_irq(pfdev);
+ panfrost_mmu_suspend_irq(pfdev);
+ panfrost_gpu_suspend_irq(pfdev);
panfrost_gpu_power_off(pfdev);
return 0;
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
index 54a8aad54259..29f89f2d3679 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -25,6 +25,12 @@ struct panfrost_perfcnt;
#define NUM_JOB_SLOTS 3
#define MAX_PM_DOMAINS 5
+enum panfrost_drv_comp_bits {
+ PANFROST_COMP_BIT_MMU,
+ PANFROST_COMP_BIT_JOB,
+ PANFROST_COMP_BIT_MAX
+};
+
/**
* enum panfrost_gpu_pm - Supported kernel power management features
* @GPU_PM_CLK_DIS: Allow disabling clocks during system suspend
@@ -109,6 +115,7 @@ struct panfrost_device {
struct panfrost_features features;
const struct panfrost_compatible *comp;
+ DECLARE_BITMAP(is_suspending, PANFROST_COMP_BIT_MAX);
spinlock_t as_lock;
unsigned long as_in_use_mask;
diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index 7adc4441fa14..2bf645993ab4 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -452,6 +452,13 @@ void panfrost_gpu_power_off(struct panfrost_device *pfdev)
dev_err(pfdev->dev, "l2 power transition timeout");
}
+void panfrost_gpu_suspend_irq(struct panfrost_device *pfdev)
+{
+ gpu_write(pfdev, GPU_INT_MASK, 0);
+ gpu_write(pfdev, GPU_INT_CLEAR, GPU_IRQ_MASK_ALL);
+ synchronize_irq(pfdev->gpu_irq);
+}
+
int panfrost_gpu_init(struct panfrost_device *pfdev)
{
int err;
diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.h b/drivers/gpu/drm/panfrost/panfrost_gpu.h
index 876fdad9f721..d841b86504ea 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.h
@@ -15,6 +15,7 @@ u32 panfrost_gpu_get_latest_flush_id(struct panfrost_device *pfdev);
int panfrost_gpu_soft_reset(struct panfrost_device *pfdev);
void panfrost_gpu_power_on(struct panfrost_device *pfdev);
void panfrost_gpu_power_off(struct panfrost_device *pfdev);
+void panfrost_gpu_suspend_irq(struct panfrost_device *pfdev);
void panfrost_cycle_counter_get(struct panfrost_device *pfdev);
void panfrost_cycle_counter_put(struct panfrost_device *pfdev);
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index f9446e197428..e8de44cc56e2 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -413,6 +413,14 @@ void panfrost_job_enable_interrupts(struct panfrost_device *pfdev)
job_write(pfdev, JOB_INT_MASK, irq_mask);
}
+void panfrost_job_suspend_irq(struct panfrost_device *pfdev)
+{
+ set_bit(PANFROST_COMP_BIT_JOB, pfdev->is_suspending);
+
+ job_write(pfdev, JOB_INT_MASK, 0);
+ synchronize_irq(pfdev->js->irq);
+}
+
static void panfrost_job_handle_err(struct panfrost_device *pfdev,
struct panfrost_job *job,
unsigned int js)
@@ -792,9 +800,13 @@ static irqreturn_t panfrost_job_irq_handler_thread(int irq, void *data)
struct panfrost_device *pfdev = data;
panfrost_job_handle_irqs(pfdev);
- job_write(pfdev, JOB_INT_MASK,
- GENMASK(16 + NUM_JOB_SLOTS - 1, 16) |
- GENMASK(NUM_JOB_SLOTS - 1, 0));
+
+ /* Enable interrupts only if we're not about to get suspended */
+ if (!test_bit(PANFROST_COMP_BIT_JOB, pfdev->is_suspending))
+ job_write(pfdev, JOB_INT_MASK,
+ GENMASK(16 + NUM_JOB_SLOTS - 1, 16) |
+ GENMASK(NUM_JOB_SLOTS - 1, 0));
+
return IRQ_HANDLED;
}
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.h b/drivers/gpu/drm/panfrost/panfrost_job.h
index 17ff808dba07..ec581b97852b 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.h
+++ b/drivers/gpu/drm/panfrost/panfrost_job.h
@@ -47,6 +47,7 @@ int panfrost_job_get_slot(struct panfrost_job *job);
int panfrost_job_push(struct panfrost_job *job);
void panfrost_job_put(struct panfrost_job *job);
void panfrost_job_enable_interrupts(struct panfrost_device *pfdev);
+void panfrost_job_suspend_irq(struct panfrost_device *pfdev);
int panfrost_job_is_idle(struct panfrost_device *pfdev);
#endif
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index ac4296c1e54b..6ccf0a65b8fb 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -744,9 +744,12 @@ static irqreturn_t panfrost_mmu_irq_handler_thread(int irq, void *data)
status = mmu_read(pfdev, MMU_INT_RAWSTAT) & ~pfdev->as_faulty_mask;
}
- spin_lock(&pfdev->as_lock);
- mmu_write(pfdev, MMU_INT_MASK, ~pfdev->as_faulty_mask);
- spin_unlock(&pfdev->as_lock);
+ /* Enable interrupts only if we're not about to get suspended */
+ if (!test_bit(PANFROST_COMP_BIT_MMU, pfdev->is_suspending)) {
+ spin_lock(&pfdev->as_lock);
+ mmu_write(pfdev, MMU_INT_MASK, ~pfdev->as_faulty_mask);
+ spin_unlock(&pfdev->as_lock);
+ }
return IRQ_HANDLED;
};
@@ -777,3 +780,11 @@ void panfrost_mmu_fini(struct panfrost_device *pfdev)
{
mmu_write(pfdev, MMU_INT_MASK, 0);
}
+
+void panfrost_mmu_suspend_irq(struct panfrost_device *pfdev)
+{
+ set_bit(PANFROST_COMP_BIT_MMU, pfdev->is_suspending);
+
+ mmu_write(pfdev, MMU_INT_MASK, 0);
+ synchronize_irq(pfdev->mmu_irq);
+}
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.h b/drivers/gpu/drm/panfrost/panfrost_mmu.h
index cc2a0d307feb..022a9a74a114 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.h
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.h
@@ -14,6 +14,7 @@ void panfrost_mmu_unmap(struct panfrost_gem_mapping *mapping);
int panfrost_mmu_init(struct panfrost_device *pfdev);
void panfrost_mmu_fini(struct panfrost_device *pfdev);
void panfrost_mmu_reset(struct panfrost_device *pfdev);
+void panfrost_mmu_suspend_irq(struct panfrost_device *pfdev);
u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu);
void panfrost_mmu_as_put(struct panfrost_device *pfdev, struct panfrost_mmu *mmu);
--
2.42.0