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@xxxxxxxxxxxxx>
Reviewed-by: Steven Price <steven.price@xxxxxxx>
> ---
> 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)
