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

[Liviu Dudau <liviu.dudau@arm.com>]

On Wed, Apr 29, 2026 at 11:38:32AM +0200, 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: Liviu Dudau <liviu.dudau@arm.com>

Best regards,
Liviu

> ---
>  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 *
> 
> -- 
> 2.53.0
> 

-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
    ¯\_(ツ)_/¯