Add a function to modify an IRQ's mask. If the IRQ is currently active,
it will write to the register, otherwise it will only set the struct
member.

There's no locking done to guarantee exclusion with the other two
functions that touch the IRQ mask, and it should only be called from a
context where the circumstances guarantee no concurrent access is
performed.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
 drivers/gpu/drm/panthor/panthor_device.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
index f35e52b9546a..894d28b3eb02 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -470,6 +470,13 @@ static int panthor_request_ ## __name ## _irq(struct panthor_device *ptdev,			\
 					 panthor_ ## __name ## _irq_threaded_handler,		\
 					 IRQF_SHARED, KBUILD_MODNAME "-" # __name,		\
 					 pirq);							\
+}												\
+												\
+static inline void panthor_ ## __name ## _irq_mask_set(struct panthor_irq *pirq, u32 mask)	\
+{												\
+	pirq->mask = mask;									\
+	if (!atomic_read(&pirq->suspended))							\
+		gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, mask);			\
 }
 
 extern struct workqueue_struct *panthor_cleanup_wq;

-- 
2.52.0