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drm/panfrost: Synchronize and disable interrupts before powering off 

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 requires 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 an `is_suspended` bitmap which is used to address the
possible corner case of unintentional IRQ unmasking because of ISR
execution after a call to synchronize_irq().

At resume, clear each is_suspended bit in the reset path of JOB/MMU
to allow unmasking the interrupts.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231204114215.54575-4-angelogioacchino.delregno@collabora.com
This commit is contained in:
AngeloGioacchino Del Regno 2023-12-04 12:42:15 +01:00 committed by Boris Brezillon
parent b98e9a84d3
commit 157ad4ccff
8 changed files with 71 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/gpu/drm/panfrost/panfrost_device.c
View File

@ -421,6 +421,9 @@ 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;

8
drivers/gpu/drm/panfrost/panfrost_device.h
View File

@ -25,6 +25,13 @@ struct panfrost_perfcnt;
#define NUM_JOB_SLOTS 3
#define MAX_PM_DOMAINS 5
enum panfrost_drv_comp_bits {
PANFROST_COMP_BIT_GPU,
PANFROST_COMP_BIT_JOB,
PANFROST_COMP_BIT_MMU,
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 +116,7 @@ struct panfrost_device {
struct panfrost_features features;
const struct panfrost_compatible *comp;
DECLARE_BITMAP(is_suspended, PANFROST_COMP_BIT_MAX);
spinlock_t as_lock;
unsigned long as_in_use_mask;

18
drivers/gpu/drm/panfrost/panfrost_gpu.c
View File

@ -22,9 +22,13 @@
static irqreturn_t panfrost_gpu_irq_handler(int irq, void *data)
{
struct panfrost_device *pfdev = data;
u32 state = gpu_read(pfdev, GPU_INT_STAT);
u32 fault_status = gpu_read(pfdev, GPU_FAULT_STATUS);
u32 fault_status, state;
if (test_bit(PANFROST_COMP_BIT_GPU, pfdev->is_suspended))
return IRQ_NONE;
fault_status = gpu_read(pfdev, GPU_FAULT_STATUS);
state = gpu_read(pfdev, GPU_INT_STAT);
if (!state)
return IRQ_NONE;
@ -61,6 +65,8 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev)
gpu_write(pfdev, GPU_INT_MASK, 0);
gpu_write(pfdev, GPU_INT_CLEAR, GPU_IRQ_RESET_COMPLETED);
clear_bit(PANFROST_COMP_BIT_GPU, pfdev->is_suspended);
gpu_write(pfdev, GPU_CMD, GPU_CMD_SOFT_RESET);
ret = readl_relaxed_poll_timeout(pfdev->iomem + GPU_INT_RAWSTAT,
val, val & GPU_IRQ_RESET_COMPLETED, 10, 10000);
@ -452,6 +458,14 @@ 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)
{
set_bit(PANFROST_COMP_BIT_GPU, pfdev->is_suspended);
gpu_write(pfdev, GPU_INT_MASK, 0);
synchronize_irq(pfdev->gpu_irq);
}
int panfrost_gpu_init(struct panfrost_device *pfdev)
{
int err;

1
drivers/gpu/drm/panfrost/panfrost_gpu.h
View File

@ -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);

26
drivers/gpu/drm/panfrost/panfrost_job.c
View File

@ -405,6 +405,8 @@ void panfrost_job_enable_interrupts(struct panfrost_device *pfdev)
int j;
u32 irq_mask = 0;
clear_bit(PANFROST_COMP_BIT_JOB, pfdev->is_suspended);
for (j = 0; j < NUM_JOB_SLOTS; j++) {
irq_mask |= MK_JS_MASK(j);
}
@ -413,6 +415,14 @@ 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_suspended);
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)
@ -792,17 +802,25 @@ 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_suspended))
job_write(pfdev, JOB_INT_MASK,
GENMASK(16 + NUM_JOB_SLOTS - 1, 16) |
GENMASK(NUM_JOB_SLOTS - 1, 0));
return IRQ_HANDLED;
}
static irqreturn_t panfrost_job_irq_handler(int irq, void *data)
{
struct panfrost_device *pfdev = data;
u32 status = job_read(pfdev, JOB_INT_STAT);
u32 status;
if (test_bit(PANFROST_COMP_BIT_JOB, pfdev->is_suspended))
return IRQ_NONE;
status = job_read(pfdev, JOB_INT_STAT);
if (!status)
return IRQ_NONE;

1
drivers/gpu/drm/panfrost/panfrost_job.h
View File

@ -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

22
drivers/gpu/drm/panfrost/panfrost_mmu.c
View File

@ -231,6 +231,8 @@ void panfrost_mmu_reset(struct panfrost_device *pfdev)
{
struct panfrost_mmu *mmu, *mmu_tmp;
clear_bit(PANFROST_COMP_BIT_MMU, pfdev->is_suspended);
spin_lock(&pfdev->as_lock);
pfdev->as_alloc_mask = 0;
@ -670,6 +672,9 @@ static irqreturn_t panfrost_mmu_irq_handler(int irq, void *data)
{
struct panfrost_device *pfdev = data;
if (test_bit(PANFROST_COMP_BIT_MMU, pfdev->is_suspended))
return IRQ_NONE;
if (!mmu_read(pfdev, MMU_INT_STAT))
return IRQ_NONE;
@ -744,9 +749,12 @@ 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_suspended)) {
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 +785,11 @@ 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_suspended);
mmu_write(pfdev, MMU_INT_MASK, 0);
synchronize_irq(pfdev->mmu_irq);
}

1
drivers/gpu/drm/panfrost/panfrost_mmu.h
View File

@ -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);