On 08/01/2026 14:19, Nicolas Frattaroli wrote:
> To deal with the threaded interrupt handler and a suspend action
> overlapping, the boolean panthor_irq::suspended is not sufficient.
>
> Rework it into taking several different values depending on the current
> state, and check it and set it within the IRQ helper functions.
>
> Signed-off-by: Nicolas Frattaroli <[email protected]>
> ---
> drivers/gpu/drm/panthor/panthor_device.h | 40
> +++++++++++++++++++++++++-------
> 1 file changed, 32 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_device.h
> b/drivers/gpu/drm/panthor/panthor_device.h
> index cf76a8abca76..a8c21a7eea05 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -61,6 +61,17 @@ enum panthor_device_pm_state {
> PANTHOR_DEVICE_PM_STATE_SUSPENDING,
> };
>
> +enum panthor_irq_state {
> + /** @PANTHOR_IRQ_STATE_ACTIVE: IRQ is active and ready to process
> events. */
> + PANTHOR_IRQ_STATE_ACTIVE = 0,
> + /** @PANTHOR_IRQ_STATE_PROCESSING: IRQ is currently processing events.
> */
> + PANTHOR_IRQ_STATE_PROCESSING,
> + /** @PANTHOR_IRQ_STATE_SUSPENDED: IRQ is suspended. */
> + PANTHOR_IRQ_STATE_SUSPENDED,
> + /** @PANTHOR_IRQ_STATE_SUSPENDING: IRQ is being suspended. */
> + PANTHOR_IRQ_STATE_SUSPENDING,
> +};
> +
> /**
> * struct panthor_irq - IRQ data
> *
> @@ -76,8 +87,8 @@ struct panthor_irq {
> /** @mask: Values to write to xxx_INT_MASK if active. */
> u32 mask;
>
> - /** @suspended: Set to true when the IRQ is suspended. */
> - atomic_t suspended;
> + /** @state: one of &enum panthor_irq_state reflecting the current
> state. */
> + atomic_t state;
>
> /** @mask_lock: protects modifications to _INT_MASK and @mask */
> spinlock_t mask_lock;
> @@ -415,7 +426,7 @@ static irqreturn_t panthor_ ## __name ##
> _irq_raw_handler(int irq, void *data)
>
> \
> guard(spinlock_irqsave)(&pirq->mask_lock);
> \
>
> \
> - if (atomic_read(&pirq->suspended))
> \
> + if (atomic_read(&pirq->state) == PANTHOR_IRQ_STATE_SUSPENDED)
> \
Do we want to also catch the STATE_SUSPENDING case here? AFAICT in
SUSPENDING we should be confident that _INT_MASK==0 so this shouldn't a
problem (_INT_STAT should read as 0 below). But we don't want interrupts
during STATE_SUSPENDING so we might as well handle it.
Thanks,
Steve
> return IRQ_NONE;
> \
> if (!gpu_read(ptdev, __reg_prefix ## _INT_STAT))
> \
> return IRQ_NONE;
> \
> @@ -428,11 +439,14 @@ static irqreturn_t panthor_ ## __name ##
> _irq_threaded_handler(int irq, void *da
> {
> \
> struct panthor_irq *pirq = data;
> \
> struct panthor_device *ptdev = pirq->ptdev;
> \
> + enum panthor_irq_state state;
> \
> irqreturn_t ret = IRQ_NONE;
> \
> u32 mask;
> \
>
> \
> scoped_guard(spinlock_irqsave, &pirq->mask_lock) {
> \
> mask = pirq->mask;
> \
> + atomic_cmpxchg(&pirq->state, PANTHOR_IRQ_STATE_ACTIVE,
> \
> + PANTHOR_IRQ_STATE_PROCESSING);
> \
> }
> \
>
> \
> while (true) {
> \
> @@ -446,11 +460,14 @@ static irqreturn_t panthor_ ## __name ##
> _irq_threaded_handler(int irq, void *da
> }
> \
>
> \
> scoped_guard(spinlock_irqsave, &pirq->mask_lock) {
> \
> - if (!atomic_read(&pirq->suspended)) {
> \
> + state = atomic_read(&pirq->state);
> \
> + if (state != PANTHOR_IRQ_STATE_SUSPENDED &&
> \
> + state != PANTHOR_IRQ_STATE_SUSPENDING) {
> \
> /* Only restore the bits that were used and are still
> enabled */ \
> gpu_write(ptdev, __reg_prefix ## _INT_MASK,
> \
> gpu_read(ptdev, __reg_prefix ## _INT_MASK) |
> \
> (mask & pirq->mask));
> \
> + atomic_set(&pirq->state, PANTHOR_IRQ_STATE_ACTIVE);
> \
> }
> \
> }
> \
>
> \
> @@ -461,16 +478,17 @@ static inline void panthor_ ## __name ##
> _irq_suspend(struct panthor_irq *pirq)
> {
> \
> scoped_guard(spinlock_irqsave, &pirq->mask_lock) {
> \
> gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, 0);
> \
> + atomic_set(&pirq->state, PANTHOR_IRQ_STATE_SUSPENDING);
> \
> }
> \
> synchronize_irq(pirq->irq);
> \
> - atomic_set(&pirq->suspended, true);
> \
> + atomic_set(&pirq->state, PANTHOR_IRQ_STATE_SUSPENDED);
> \
> }
> \
>
> \
> static inline void panthor_ ## __name ## _irq_resume(struct panthor_irq
> *pirq) \
> {
> \
> guard(spinlock_irqsave)(&pirq->mask_lock);
> \
>
> \
> - atomic_set(&pirq->suspended, false);
> \
> + atomic_set(&pirq->state, PANTHOR_IRQ_STATE_ACTIVE);
> \
> gpu_write(pirq->ptdev, __reg_prefix ## _INT_CLEAR, pirq->mask);
> \
> gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, pirq->mask);
> \
> }
> \
> @@ -494,19 +512,25 @@ static int panthor_request_ ## __name ## _irq(struct
> panthor_device *ptdev, \
>
> \
> static inline void panthor_ ## __name ## _irq_enable_events(struct
> panthor_irq *pirq, u32 mask) \
> {
> \
> + enum panthor_irq_state state;
> \
> +
> \
> guard(spinlock_irqsave)(&pirq->mask_lock);
> \
>
> \
> pirq->mask |= mask;
> \
> - if (!atomic_read(&pirq->suspended))
> \
> + state = atomic_read(&pirq->state);
> \
> + if (state != PANTHOR_IRQ_STATE_SUSPENDED && state !=
> PANTHOR_IRQ_STATE_SUSPENDING) \
> gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, pirq->mask);
> \
> }
> \
>
> \
> static inline void panthor_ ## __name ## _irq_disable_events(struct
> panthor_irq *pirq, u32 mask)\
> {
> \
> + enum panthor_irq_state state;
> \
> +
> \
> guard(spinlock_irqsave)(&pirq->mask_lock);
> \
>
> \
> pirq->mask &= ~mask;
> \
> - if (!atomic_read(&pirq->suspended))
> \
> + state = atomic_read(&pirq->state);
> \
> + if (state != PANTHOR_IRQ_STATE_SUSPENDED && state !=
> PANTHOR_IRQ_STATE_SUSPENDING) \
> gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, pirq->mask);
> \
> }
>
>
