Re: [PATCH 6/9] drm/panfrost: Avoid re-enabling job interrupts in the reset path

[Boris Brezillon <boris.brezillon@collabora.com>]

On Tue, 15 Oct 2024 00:31:41 +0100
Adrián Larumbe <adrian.larumbe@collabora.com> wrote:

> Rather than remasking interrupts after a device reset in the main reset
> path, allow selecting whether to do this with an additional bool parameter.
> 
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> ---
>  drivers/gpu/drm/panfrost/panfrost_device.c |  6 +++---
>  drivers/gpu/drm/panfrost/panfrost_device.h |  2 +-
>  drivers/gpu/drm/panfrost/panfrost_job.c    | 14 +++++---------
>  drivers/gpu/drm/panfrost/panfrost_job.h    |  2 +-
>  4 files changed, 10 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
> index 4fe29286bbe3..a2a58501cbd9 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.c
> @@ -395,20 +395,20 @@ bool panfrost_exception_needs_reset(const struct panfrost_device *pfdev,
>  	return false;
>  }
>  
> -void panfrost_device_reset(struct panfrost_device *pfdev)
> +void panfrost_device_reset(struct panfrost_device *pfdev, bool enable_job_int)
>  {
>  	panfrost_gpu_soft_reset(pfdev);
>  
>  	panfrost_gpu_power_on(pfdev);
>  	panfrost_mmu_reset(pfdev);
> -	panfrost_job_enable_interrupts(pfdev);
> +	panfrost_job_enable_interrupts(pfdev, enable_job_int);
>  }
>  
>  static int panfrost_device_runtime_resume(struct device *dev)
>  {
>  	struct panfrost_device *pfdev = dev_get_drvdata(dev);
>  
> -	panfrost_device_reset(pfdev);
> +	panfrost_device_reset(pfdev, true);
>  	panfrost_devfreq_resume(pfdev);
>  
>  	return 0;
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
> index d9aea2c2cbe5..fc83d5e104a3 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.h
> @@ -205,7 +205,7 @@ int panfrost_unstable_ioctl_check(void);
>  
>  int panfrost_device_init(struct panfrost_device *pfdev);
>  void panfrost_device_fini(struct panfrost_device *pfdev);
> -void panfrost_device_reset(struct panfrost_device *pfdev);
> +void panfrost_device_reset(struct panfrost_device *pfdev, bool enable_job_int);
>  
>  extern const struct dev_pm_ops panfrost_pm_ops;
>  
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 52ec9dc2397c..68be555c6c52 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -414,7 +414,7 @@ static struct dma_fence *panfrost_job_run(struct drm_sched_job *sched_job)
>  	return fence;
>  }
>  
> -void panfrost_job_enable_interrupts(struct panfrost_device *pfdev)
> +void panfrost_job_enable_interrupts(struct panfrost_device *pfdev, bool enable_job_int)
>  {
>  	int j;
>  	u32 irq_mask = 0;
> @@ -426,7 +426,8 @@ void panfrost_job_enable_interrupts(struct panfrost_device *pfdev)
>  	}
>  
>  	job_write(pfdev, JOB_INT_CLEAR, irq_mask);
> -	job_write(pfdev, JOB_INT_MASK, irq_mask);
> +	if (enable_job_int)
> +		job_write(pfdev, JOB_INT_MASK, irq_mask);
>  }

This makes things utterly confusing. Now you have a function named
panfrost_job_enable_interrupts() with a boolean encoding whether you
want to enable interrupts or not. If we really want to dissociate the
two things done in panfrost_job_enable_interrupts(), I'd rather go for
a reset_interrupts()/enable_interrupts() split, with reset_interrupts
clearing the IRQs, and enable_interrupts() unmasking the interrupts and
clearing the COMP_BIT_JOB bit.

>  
>  void panfrost_job_suspend_irq(struct panfrost_device *pfdev)
> @@ -718,12 +719,7 @@ panfrost_reset(struct panfrost_device *pfdev,
>  	spin_unlock(&pfdev->js->job_lock);
>  
>  	/* Proceed with reset now. */
> -	panfrost_device_reset(pfdev);
> -
> -	/* panfrost_device_reset() unmasks job interrupts, but we want to
> -	 * keep them masked a bit longer.
> -	 */
> -	job_write(pfdev, JOB_INT_MASK, 0);
> +	panfrost_device_reset(pfdev, false);
>  
>  	/* GPU has been reset, we can clear the reset pending bit. */
>  	atomic_set(&pfdev->reset.pending, 0);
> @@ -898,7 +894,7 @@ int panfrost_job_init(struct panfrost_device *pfdev)
>  		}
>  	}
>  
> -	panfrost_job_enable_interrupts(pfdev);
> +	panfrost_job_enable_interrupts(pfdev, true);
>  
>  	return 0;
>  
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.h b/drivers/gpu/drm/panfrost/panfrost_job.h
> index ec581b97852b..3b8b712c1722 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.h
> @@ -46,7 +46,7 @@ void panfrost_job_close(struct panfrost_file_priv *panfrost_priv);
>  int panfrost_job_get_slot(struct panfrost_job *job);
>  int panfrost_job_push(struct panfrost_job *job);
>  void panfrost_job_put(struct panfrost_job *job);
> -void panfrost_job_enable_interrupts(struct panfrost_device *pfdev);
> +void panfrost_job_enable_interrupts(struct panfrost_device *pfdev, bool enable_job_int);
>  void panfrost_job_suspend_irq(struct panfrost_device *pfdev);
>  int panfrost_job_is_idle(struct panfrost_device *pfdev);
>