Re: [PATCH v2 4/8] drm/panthor: Store IRQ register base iomem pointer in panthor_irq

[Steven Price <steven.price@arm.com>]

On 12/04/2026 15:29, Karunika Choo wrote:
> Update common IRQ handling code to work from an IRQ-local iomem base
> instead of referencing block-specific interrupt register offsets.
> 
> Store the interrupt base address iomem pointer in struct panthor_irq and
> switch the shared IRQ helpers to use generic INT_* offsets from that
> local base. This removes the need for each caller to expose absolute IRQ
> register addresses while keeping the common IRQ flow unchanged.
> 
> No functional change intended.
> 
> v2:
> - Change IRQ request function to accept an iomem pointer instead of
>   computing it from an offset argument.
> 
> Signed-off-by: Karunika Choo <karunika.choo@arm.com>

One minor comment below...

> ---
>  drivers/gpu/drm/panthor/panthor_device.h   | 32 ++++++++++++++--------
>  drivers/gpu/drm/panthor/panthor_fw.c       |  5 ++--
>  drivers/gpu/drm/panthor/panthor_fw_regs.h  |  2 ++
>  drivers/gpu/drm/panthor/panthor_gpu.c      |  6 ++--
>  drivers/gpu/drm/panthor/panthor_gpu_regs.h |  3 ++
>  drivers/gpu/drm/panthor/panthor_mmu.c      |  5 ++--
>  drivers/gpu/drm/panthor/panthor_mmu_regs.h |  3 ++
>  drivers/gpu/drm/panthor/panthor_pwr.c      |  6 ++--
>  8 files changed, 42 insertions(+), 20 deletions(-)
> 
[...]
> @@ -1470,7 +1470,8 @@ int panthor_fw_init(struct panthor_device *ptdev)
>  	if (irq <= 0)
>  		return -ENODEV;
>  
> -	ret = panthor_request_job_irq(ptdev, &fw->irq, irq, 0);
> +	ret = panthor_request_job_irq(ptdev, &fw->irq, irq, 0,
> +				      ptdev->iomem + JOB_INT_BASE);
>  	if (ret) {
>  		drm_err(&ptdev->base, "failed to request job irq");
>  		return ret;
[..]
> @@ -162,7 +162,9 @@ int panthor_gpu_init(struct panthor_device *ptdev)
>  	if (irq < 0)
>  		return irq;
>  
> -	ret = panthor_request_gpu_irq(ptdev, &ptdev->gpu->irq, irq, GPU_INTERRUPTS_MASK);
> +	ret = panthor_request_gpu_irq(ptdev, &ptdev->gpu->irq, irq,
> +				      GPU_INTERRUPTS_MASK,
> +				      ptdev->iomem + GPU_INT_BASE);
>  	if (ret)
>  		return ret;
>  
[...]
> @@ -3229,7 +3229,8 @@ int panthor_mmu_init(struct panthor_device *ptdev)
>  		return -ENODEV;
>  
>  	ret = panthor_request_mmu_irq(ptdev, &mmu->irq, irq,
> -				      panthor_mmu_fault_mask(ptdev, ~0));
> +				      panthor_mmu_fault_mask(ptdev, ~0),
> +				      ptdev->iomem + MMU_INT_BASE);
>  	if (ret)
>  		return ret;
>  
[...]
> diff --git a/drivers/gpu/drm/panthor/panthor_pwr.c b/drivers/gpu/drm/panthor/panthor_pwr.c
> index aafb0c5c7d23..11c43de1ddd5 100644
> --- a/drivers/gpu/drm/panthor/panthor_pwr.c
> +++ b/drivers/gpu/drm/panthor/panthor_pwr.c
> @@ -70,7 +70,7 @@ static void panthor_pwr_irq_handler(struct panthor_device *ptdev, u32 status)
>  	}
>  	spin_unlock(&ptdev->pwr->reqs_lock);
>  }
> -PANTHOR_IRQ_HANDLER(pwr, PWR, panthor_pwr_irq_handler);
> +PANTHOR_IRQ_HANDLER(pwr, panthor_pwr_irq_handler);
>  
>  static void panthor_pwr_write_command(struct panthor_device *ptdev, u32 command, u64 args)
>  {
> @@ -464,7 +464,9 @@ int panthor_pwr_init(struct panthor_device *ptdev)
>  	if (irq < 0)
>  		return irq;
>  
> -	err = panthor_request_pwr_irq(ptdev, &pwr->irq, irq, PWR_INTERRUPTS_MASK);
> +	err = panthor_request_pwr_irq(
> +		ptdev, &pwr->irq, irq, PWR_INTERRUPTS_MASK,
> +		ptdev->iomem + GPU_CONTROL_BASE + PWR_CONTROL_BASE);

This one is the odd one out because it adds GPU_CONTROL_BASE put the
other panthor_request_xxx_irq() calls don't. Sashiko also points out
that there's an argument these should all be using ptdev->gpu->iomem in
the final refactor.

Thanks,
Steve

>  	if (err)
>  		return err;
>