Re: [PATCH v2 6/8] drm/panfrost: Make re-enabling job interrupts at device reset optional

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

On Thu, 28 Nov 2024 21:06:21 +0000
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.
> 
> To this end, split reenabling job interrupts into two functions, one that
> clears the interrupts and another one which unmasks them conditionally.
> 
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> ---
>  drivers/gpu/drm/panfrost/panfrost_device.c | 11 +++++--
>  drivers/gpu/drm/panfrost/panfrost_device.h |  2 +-
>  drivers/gpu/drm/panfrost/panfrost_job.c    | 34 ++++++++++++----------
>  drivers/gpu/drm/panfrost/panfrost_job.h    |  3 +-
>  4 files changed, 29 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
> index 4fe29286bbe3..7e5d39699982 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.c
> @@ -395,20 +395,25 @@ 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)
>  {
> +	u32 irq_mask;
> +
>  	panfrost_gpu_soft_reset(pfdev);
>  
>  	panfrost_gpu_power_on(pfdev);
>  	panfrost_mmu_reset(pfdev);
> -	panfrost_job_enable_interrupts(pfdev);
> +
> +	irq_mask = panfrost_job_reset_interrupts(pfdev);
> +	if (enable_job_int)
> +		panfrost_enable_interrupts(pfdev, irq_mask);
>  }
>  
>  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 fba1a376f593..79d2ee3625b2 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -27,6 +27,10 @@
>  #define job_write(dev, reg, data) writel(data, dev->iomem + (reg))
>  #define job_read(dev, reg) readl(dev->iomem + (reg))
>  
> +#define JOB_INT_ENABLE_MASK			\
> +	(GENMASK(16 + NUM_JOB_SLOTS - 1, 16) |	\
> +	 GENMASK(NUM_JOB_SLOTS - 1, 0))
> +
>  struct panfrost_queue_state {
>  	struct drm_gpu_scheduler sched;
>  	u64 fence_context;
> @@ -421,18 +425,23 @@ static struct dma_fence *panfrost_job_run(struct drm_sched_job *sched_job)
>  	return fence;
>  }
>  
> -void panfrost_job_enable_interrupts(struct panfrost_device *pfdev)
> +u32 panfrost_job_reset_interrupts(struct panfrost_device *pfdev)
>  {
>  	int j;
>  	u32 irq_mask = 0;
>  
> -	clear_bit(PANFROST_COMP_BIT_JOB, pfdev->is_suspended);
> -
>  	for (j = 0; j < NUM_JOB_SLOTS; j++) {
>  		irq_mask |= MK_JS_MASK(j);
>  	}
>  
>  	job_write(pfdev, JOB_INT_CLEAR, irq_mask);
> +
> +	return irq_mask;
> +}

Let's define an ALL_JS_INT_MASK so we can get rid of the for loop and
can avoid returning a value that's constant.

> +
> +void panfrost_enable_interrupts(struct panfrost_device *pfdev, u32 irq_mask)

Let's drop the irq_mask mask (use ALL_JS_INT_MASK), and call the
function panfrost_job_enable_interrupts() instead.

> +{
> +	clear_bit(PANFROST_COMP_BIT_JOB, pfdev->is_suspended);
>  	job_write(pfdev, JOB_INT_MASK, irq_mask);
>  }
>  
> @@ -725,12 +734,7 @@ 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);
> @@ -752,9 +756,7 @@ panfrost_reset(struct panfrost_device *pfdev,
>  		drm_sched_start(&pfdev->js->queue[i].sched, 0);
>  
>  	/* Re-enable job interrupts now that everything has been restarted. */
> -	job_write(pfdev, JOB_INT_MASK,
> -		  GENMASK(16 + NUM_JOB_SLOTS - 1, 16) |
> -		  GENMASK(NUM_JOB_SLOTS - 1, 0));
> +	panfrost_enable_interrupts(pfdev, JOB_INT_ENABLE_MASK);
>  
>  	dma_fence_end_signalling(cookie);
>  }
> @@ -827,9 +829,7 @@ static irqreturn_t panfrost_job_irq_handler_thread(int irq, void *data)
>  
>  	/* Enable interrupts only if we're not about to get suspended */
>  	if (!test_bit(PANFROST_COMP_BIT_JOB, pfdev->is_suspended))
> -		job_write(pfdev, JOB_INT_MASK,
> -			  GENMASK(16 + NUM_JOB_SLOTS - 1, 16) |
> -			  GENMASK(NUM_JOB_SLOTS - 1, 0));
> +		job_write(pfdev, JOB_INT_MASK, JOB_INT_ENABLE_MASK);
>  
>  	return IRQ_HANDLED;
>  }
> @@ -854,6 +854,7 @@ int panfrost_job_init(struct panfrost_device *pfdev)
>  {
>  	struct panfrost_job_slot *js;
>  	unsigned int nentries = 2;
> +	u32 irq_mask;
>  	int ret, j;
>  
>  	/* All GPUs have two entries per queue, but without jobchain
> @@ -905,7 +906,8 @@ int panfrost_job_init(struct panfrost_device *pfdev)
>  		}
>  	}
>  
> -	panfrost_job_enable_interrupts(pfdev);
> +	irq_mask = panfrost_job_reset_interrupts(pfdev);
> +	panfrost_enable_interrupts(pfdev, irq_mask);
>  
>  	return 0;
>  
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.h b/drivers/gpu/drm/panfrost/panfrost_job.h
> index ec581b97852b..c09d42ee5039 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.h
> @@ -46,7 +46,8 @@ 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);
> +u32 panfrost_job_reset_interrupts(struct panfrost_device *pfdev);
> +void panfrost_enable_interrupts(struct panfrost_device *pfdev, u32 irq_mask);
>  void panfrost_job_suspend_irq(struct panfrost_device *pfdev);
>  int panfrost_job_is_idle(struct panfrost_device *pfdev);
>