On 09/09/2020 14:23, Steven Price wrote:
On 08/09/2020 16:18, Neil Armstrong wrote:
The T820, G31 & G52 GPUs integratewd by Amlogic in the respective GXM, G12A/SM1 & G12B SoCs needs a quirk in the PWR registers at the GPU reset time.
This adds a callback in the device compatible struct of permit this.
Signed-off-by: Neil Armstrong narmstrong@baylibre.com
drivers/gpu/drm/panfrost/panfrost_device.h | 3 +++ drivers/gpu/drm/panfrost/panfrost_gpu.c | 4 ++++ 2 files changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h index 2cf1a6a13af8..4c9cd5452ba5 100644 --- a/drivers/gpu/drm/panfrost/panfrost_device.h +++ b/drivers/gpu/drm/panfrost/panfrost_device.h @@ -73,6 +73,9 @@ struct panfrost_compatible { /* IOMMU quirks flags */ unsigned long pgtbl_quirks;
+ /* Vendor implementation quirks at reset time callback */ + void (*vendor_reset_quirk)(struct panfrost_device *pfdev); }; struct panfrost_device { diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c index e0f190e43813..c129aaf77790 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gpu.c +++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c @@ -62,6 +62,10 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev) gpu_write(pfdev, GPU_INT_CLEAR, GPU_IRQ_RESET_COMPLETED); gpu_write(pfdev, GPU_CMD, GPU_CMD_SOFT_RESET); + /* The Amlogic GPU integration needs quirks at this stage */ + if (pfdev->comp->vendor_reset_quirk) + pfdev->comp->vendor_reset_quirk(pfdev);
ret = readl_relaxed_poll_timeout(pfdev->iomem + GPU_INT_RAWSTAT, val, val & GPU_IRQ_RESET_COMPLETED, 100, 10000);
Placing the quirk before the reset has completed is dodgy. Can this be ordered after the GPU_IRQ_RESET_COMPLETED signal has been seen? The problem is the reset could (in theory) cause a power transition (e.g. if the GPU is reset while a core is powered) and changing the PWR_OVERRIDEx registers during a transition is undefined. But I don't know the details of how the hardware is broken so it is possible the override is needed for the reset to complete so this would need testing.
I also wonder if this could live in panfrost_gpu_init_quirks() instead? Although that is mostly about quirks common to all Mali GPU implementations rather than a specific implementation. Although now I've looked I've noticed we have a bug as we don't appear to reapply those quirks after a reset - I'll send a patch!
Indeed, it needs to be applied after each reset, so if you send a patch for this pretty sure it could live in panfrost_gpu_init_quirks().
Neil
Steve