Re: [PATCH 05/10] drm/panthor: Make panthor_fw_{update,toggle}_reqs() callable from IRQ context

Steven Price
2026-05-01T13:40:01Z

On 29/04/2026 10:38, Boris Brezillon wrote:
> If we want some FW events to be processed in the interrupt path, we need
> the helpers manipulating req regs to be IRQ-safe, which implies using
> spin_lock_irqsave instead of spinlock. While at it, use guards instead
> of plain spin_lock/unlock calls.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>

Reviewed-by: Steven Price <steven.price@arm.com>

> ---
> drivers/gpu/drm/panthor/panthor_fw.h | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.h b/drivers/gpu/drm/panthor/panthor_fw.h
> index a99a9b6f4825..e56b7fe15bb3 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.h
> +++ b/drivers/gpu/drm/panthor/panthor_fw.h
> @@ -432,12 +432,11 @@ struct panthor_fw_global_iface {
> #define panthor_fw_toggle_reqs(__iface, __in_reg, __out_reg, __mask) \
> do { \
> u32 __cur_val, __new_val, __out_val; \
> - spin_lock(&(__iface)->lock); \
> + guard(spinlock_irqsave)(&(__iface)->lock); \
> __cur_val = READ_ONCE((__iface)->input->__in_reg); \
> __out_val = READ_ONCE((__iface)->output->__out_reg); \
> __new_val = ((__out_val ^ (__mask)) & (__mask)) | (__cur_val & ~(__mask)); \
> WRITE_ONCE((__iface)->input->__in_reg, __new_val); \
> - spin_unlock(&(__iface)->lock); \
> } while (0)
>
> /**
> @@ -458,21 +457,19 @@ struct panthor_fw_global_iface {
> #define panthor_fw_update_reqs(__iface, __in_reg, __val, __mask) \
> do { \
> u32 __cur_val, __new_val; \
> - spin_lock(&(__iface)->lock); \
> + guard(spinlock_irqsave)(&(__iface)->lock); \
> __cur_val = READ_ONCE((__iface)->input->__in_reg); \
> __new_val = (__cur_val & ~(__mask)) | ((__val) & (__mask)); \
> WRITE_ONCE((__iface)->input->__in_reg, __new_val); \
> - spin_unlock(&(__iface)->lock); \
> } while (0)
>
> #define panthor_fw_update_reqs64(__iface, __in_reg, __val, __mask) \
> do { \
> u64 __cur_val, __new_val; \
> - spin_lock(&(__iface)->lock); \
> + guard(spinlock_irqsave)(&(__iface)->lock); \
> __cur_val = READ_ONCE((__iface)->input->__in_reg); \
> __new_val = (__cur_val & ~(__mask)) | ((__val) & (__mask)); \
> WRITE_ONCE((__iface)->input->__in_reg, __new_val); \
> - spin_unlock(&(__iface)->lock); \
> } while (0)
>
> struct panthor_fw_global_iface *
>