On Mon, 12 Jan 2026 15:37:50 +0100 Nicolas Frattaroli <[email protected]> wrote:
> The current IRQ helpers do not guarantee mutual exclusion that covers > the entire transaction from accessing the mask member and modifying the > mask register. > > This makes it hard, if not impossible, to implement mask modification > helpers that may change one of these outside the normal > suspend/resume/isr code paths. > > Add a spinlock to struct panthor_irq that protects both the mask member > and register. Acquire it in all code paths that access these, but drop > it before processing the threaded handler function. Then, add the > aforementioned new helpers: enable_events, and disable_events. They work > by ORing and NANDing the mask bits. > > resume is changed to no longer have a mask passed, as pirq->mask is > supposed to be the user-requested mask now, rather than a mirror of the > INT_MASK register contents. Users of the resume helper are adjusted > accordingly, including a rather painful refactor in panthor_mmu.c. > > Signed-off-by: Nicolas Frattaroli <[email protected]> > --- > drivers/gpu/drm/panthor/panthor_device.h | 72 +++++++-- > drivers/gpu/drm/panthor/panthor_fw.c | 3 +- > drivers/gpu/drm/panthor/panthor_gpu.c | 2 +- > drivers/gpu/drm/panthor/panthor_mmu.c | 247 > ++++++++++++++++--------------- > drivers/gpu/drm/panthor/panthor_pwr.c | 2 +- > 5 files changed, 187 insertions(+), 139 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_device.h > b/drivers/gpu/drm/panthor/panthor_device.h > index 424f6cd1a814..0a29234ac58c 100644 > --- a/drivers/gpu/drm/panthor/panthor_device.h > +++ b/drivers/gpu/drm/panthor/panthor_device.h > @@ -84,11 +84,14 @@ struct panthor_irq { > /** @irq: IRQ number. */ > int irq; > > - /** @mask: Current mask being applied to xxx_INT_MASK. */ > + /** @mask: Values to write to xxx_INT_MASK if active. */ > u32 mask; > > /** @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; nit: Can we move this mask_lock right after the mask field?
