diff mbox series

[v3,1/3] drm/panfrost: Ignore core_mask for poweroff and disable PWRTRANS irq

Message ID 20231201104027.35273-2-angelogioacchino.delregno@collabora.com
State New
Headers
Series drm/panfrost: Fix poweroff and sync IRQs for suspend |

Commit Message

AngeloGioacchino Del Regno Dec. 1, 2023, 10:40 a.m. UTC 
  Some SoCs may be equipped with a GPU containing two core groups
and this is exactly the case of Samsung's Exynos 5422 featuring
an ARM Mali-T628 MP6 GPU: the support for this GPU in Panfrost
is partial, as this driver currently supports using only one
core group and that's reflected on all parts of it, including
the power on (and power off, previously to this patch) function.

The issue with this is that even though executing the soft reset
operation should power off all cores unconditionally, on at least
one platform we're seeing a crash that seems to be happening due
to an interrupt firing which may be because we are calling power
transition only on the first core group, leaving the second one
unchanged, or because ISR execution was pending before entering
the panfrost_gpu_power_off() function and executed after powering
off the GPU cores, or all of the above.

Finally, solve this by:
 - Avoid to enable the power transition interrupt on reset; and
 - Ignoring the core_mask and ask the GPU to poweroff both core groups

Fixes: 22aa1a209018 ("drm/panfrost: Really power off GPU cores in panfrost_gpu_power_off()")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/gpu/drm/panfrost/panfrost_gpu.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

Comments

Boris Brezillon Dec. 1, 2023, 10:59 a.m. UTC | #1 
On Fri,  1 Dec 2023 11:40:25 +0100
AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
wrote:

> Some SoCs may be equipped with a GPU containing two core groups
> and this is exactly the case of Samsung's Exynos 5422 featuring
> an ARM Mali-T628 MP6 GPU: the support for this GPU in Panfrost
> is partial, as this driver currently supports using only one
> core group and that's reflected on all parts of it, including
> the power on (and power off, previously to this patch) function.
> 
> The issue with this is that even though executing the soft reset
> operation should power off all cores unconditionally, on at least
> one platform we're seeing a crash that seems to be happening due
> to an interrupt firing which may be because we are calling power

                               ^ might be caused by us doing a power
  transition on the first core group only, leaving the second one
  unchanged.

> transition only on the first core group, leaving the second one
> unchanged, or because ISR execution was pending before entering

  unchanged. Our changes to the suspend logic seems to have
  uncovered another issue where the GPU interrupt handler is called
  after the device as entered the suspend state, which leads to invalid
  register accesses because the GPU device is no longer
  powered/clocked. Given the only addition that was done to the suspend
  logic is the power-off requests, and the fact those generate PWRTRANS
  interrupts, we have good reason to think the interrupts we are asked
  to process in that case are the PWRTRANS ones.

> the panfrost_gpu_power_off() function and executed after powering
> off the GPU cores, or all of the above.
> 
> Finally, solve this by:
>  - Avoid to enable the power transition interrupt on reset; and
     ^ 'Avoiding' or maybe 'Not enabling power transition ...'

>  - Ignoring the core_mask and ask the GPU to poweroff both core groups
> 
> Fixes: 22aa1a209018 ("drm/panfrost: Really power off GPU cores in panfrost_gpu_power_off()")
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Still

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  drivers/gpu/drm/panfrost/panfrost_gpu.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> index 09f5e1563ebd..bd41617c5e4b 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> @@ -78,7 +78,12 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev)
>  	}
>  
>  	gpu_write(pfdev, GPU_INT_CLEAR, GPU_IRQ_MASK_ALL);
> -	gpu_write(pfdev, GPU_INT_MASK, GPU_IRQ_MASK_ALL);
> +
> +	/* Only enable the interrupts we care about */
> +	gpu_write(pfdev, GPU_INT_MASK,
> +		  GPU_IRQ_MASK_ERROR |
> +		  GPU_IRQ_PERFCNT_SAMPLE_COMPLETED |
> +		  GPU_IRQ_CLEAN_CACHES_COMPLETED);
>  
>  	/*
>  	 * All in-flight jobs should have released their cycle
> @@ -425,11 +430,10 @@ void panfrost_gpu_power_on(struct panfrost_device *pfdev)
>  
>  void panfrost_gpu_power_off(struct panfrost_device *pfdev)
>  {
> -	u64 core_mask = panfrost_get_core_mask(pfdev);
>  	int ret;
>  	u32 val;
>  
> -	gpu_write(pfdev, SHADER_PWROFF_LO, pfdev->features.shader_present & core_mask);
> +	gpu_write(pfdev, SHADER_PWROFF_LO, pfdev->features.shader_present);
>  	ret = readl_relaxed_poll_timeout(pfdev->iomem + SHADER_PWRTRANS_LO,
>  					 val, !val, 1, 1000);
>  	if (ret)
> @@ -441,7 +445,7 @@ void panfrost_gpu_power_off(struct panfrost_device *pfdev)
>  	if (ret)
>  		dev_err(pfdev->dev, "tiler power transition timeout");
>  
> -	gpu_write(pfdev, L2_PWROFF_LO, pfdev->features.l2_present & core_mask);
> +	gpu_write(pfdev, L2_PWROFF_LO, pfdev->features.l2_present);
>  	ret = readl_poll_timeout(pfdev->iomem + L2_PWRTRANS_LO,
>  				 val, !val, 0, 1000);
>  	if (ret)
Steven Price Dec. 1, 2023, 12:34 p.m. UTC | #2 
On 01/12/2023 10:40, AngeloGioacchino Del Regno wrote:
> Some SoCs may be equipped with a GPU containing two core groups
> and this is exactly the case of Samsung's Exynos 5422 featuring
> an ARM Mali-T628 MP6 GPU: the support for this GPU in Panfrost
> is partial, as this driver currently supports using only one
> core group and that's reflected on all parts of it, including
> the power on (and power off, previously to this patch) function.
> 
> The issue with this is that even though executing the soft reset
> operation should power off all cores unconditionally, on at least
> one platform we're seeing a crash that seems to be happening due
> to an interrupt firing which may be because we are calling power
> transition only on the first core group, leaving the second one
> unchanged, or because ISR execution was pending before entering
> the panfrost_gpu_power_off() function and executed after powering
> off the GPU cores, or all of the above.
> 
> Finally, solve this by:
>  - Avoid to enable the power transition interrupt on reset; and
>  - Ignoring the core_mask and ask the GPU to poweroff both core groups
> 
> Fixes: 22aa1a209018 ("drm/panfrost: Really power off GPU cores in panfrost_gpu_power_off()")
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Reviewed-by: Steven Price <steven.price@arm.com>

> ---
>  drivers/gpu/drm/panfrost/panfrost_gpu.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> index 09f5e1563ebd..bd41617c5e4b 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> @@ -78,7 +78,12 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev)
>  	}
>  
>  	gpu_write(pfdev, GPU_INT_CLEAR, GPU_IRQ_MASK_ALL);
> -	gpu_write(pfdev, GPU_INT_MASK, GPU_IRQ_MASK_ALL);
> +
> +	/* Only enable the interrupts we care about */
> +	gpu_write(pfdev, GPU_INT_MASK,
> +		  GPU_IRQ_MASK_ERROR |
> +		  GPU_IRQ_PERFCNT_SAMPLE_COMPLETED |
> +		  GPU_IRQ_CLEAN_CACHES_COMPLETED);
>  
>  	/*
>  	 * All in-flight jobs should have released their cycle
> @@ -425,11 +430,10 @@ void panfrost_gpu_power_on(struct panfrost_device *pfdev)
>  
>  void panfrost_gpu_power_off(struct panfrost_device *pfdev)
>  {
> -	u64 core_mask = panfrost_get_core_mask(pfdev);
>  	int ret;
>  	u32 val;
>  
> -	gpu_write(pfdev, SHADER_PWROFF_LO, pfdev->features.shader_present & core_mask);
> +	gpu_write(pfdev, SHADER_PWROFF_LO, pfdev->features.shader_present);
>  	ret = readl_relaxed_poll_timeout(pfdev->iomem + SHADER_PWRTRANS_LO,
>  					 val, !val, 1, 1000);
>  	if (ret)
> @@ -441,7 +445,7 @@ void panfrost_gpu_power_off(struct panfrost_device *pfdev)
>  	if (ret)
>  		dev_err(pfdev->dev, "tiler power transition timeout");
>  
> -	gpu_write(pfdev, L2_PWROFF_LO, pfdev->features.l2_present & core_mask);
> +	gpu_write(pfdev, L2_PWROFF_LO, pfdev->features.l2_present);
>  	ret = readl_poll_timeout(pfdev->iomem + L2_PWRTRANS_LO,
>  				 val, !val, 0, 1000);
>  	if (ret)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index 09f5e1563ebd..bd41617c5e4b 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -78,7 +78,12 @@  int panfrost_gpu_soft_reset(struct panfrost_device *pfdev)
 	}
 
 	gpu_write(pfdev, GPU_INT_CLEAR, GPU_IRQ_MASK_ALL);
-	gpu_write(pfdev, GPU_INT_MASK, GPU_IRQ_MASK_ALL);
+
+	/* Only enable the interrupts we care about */
+	gpu_write(pfdev, GPU_INT_MASK,
+		  GPU_IRQ_MASK_ERROR |
+		  GPU_IRQ_PERFCNT_SAMPLE_COMPLETED |
+		  GPU_IRQ_CLEAN_CACHES_COMPLETED);
 
 	/*
 	 * All in-flight jobs should have released their cycle
@@ -425,11 +430,10 @@  void panfrost_gpu_power_on(struct panfrost_device *pfdev)
 
 void panfrost_gpu_power_off(struct panfrost_device *pfdev)
 {
-	u64 core_mask = panfrost_get_core_mask(pfdev);
 	int ret;
 	u32 val;
 
-	gpu_write(pfdev, SHADER_PWROFF_LO, pfdev->features.shader_present & core_mask);
+	gpu_write(pfdev, SHADER_PWROFF_LO, pfdev->features.shader_present);
 	ret = readl_relaxed_poll_timeout(pfdev->iomem + SHADER_PWRTRANS_LO,
 					 val, !val, 1, 1000);
 	if (ret)
@@ -441,7 +445,7 @@  void panfrost_gpu_power_off(struct panfrost_device *pfdev)
 	if (ret)
 		dev_err(pfdev->dev, "tiler power transition timeout");
 
-	gpu_write(pfdev, L2_PWROFF_LO, pfdev->features.l2_present & core_mask);
+	gpu_write(pfdev, L2_PWROFF_LO, pfdev->features.l2_present);
 	ret = readl_poll_timeout(pfdev->iomem + L2_PWRTRANS_LO,
 				 val, !val, 0, 1000);
 	if (ret)