Re: [PATCH v2 05/11] drm/panthor: Make panthor_fw_{update, toggle}_reqs() callable from IRQ context

[Chia-I Wu <olvaffe@gmail.com>]

On Tue, May 12, 2026 at 4:54 AM Boris Brezillon
<boris.brezillon@collabora.com> 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.
>
> Reviewed-by: Steven Price <steven.price@arm.com>
> Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.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 *
>
> --
> 2.54.0
>