Re: [RFC 8/8] drm/nouveau: introduce the scrubber on Ada in a kernel doc

[Danilo Krummrich <dakr@kernel.org>]

On Fri, Nov 22, 2024 at 04:57:12AM -0800, Zhi Wang wrote:
> Introduce a kernel doc to explain the scrubber on Ada.
> 
> Cc: Milos Tijanic <mtijanic@nvidia.com>
> Signed-off-by: Zhi Wang <zhiw@nvidia.com>
> ---
>  drivers/gpu/drm/nouveau/nvkm/subdev/gsp/ad102.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/ad102.c b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/ad102.c
> index 80d6d73fe352..327e733e3e8b 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/ad102.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/ad102.c
> @@ -24,6 +24,20 @@
>  #include <engine/sec2.h>
>  #include "priv.h"
>  
> +/*
> + * DOC: Pre-scrubbed FB memory on Ada
> + *
> + * https://github.com/NVIDIA/open-gpu-kernel-modules/blob/565.57.01/src/nvidia/src/kernel/gpu/gsp/kernel_gsp.c#L3151
> + *
> + * The size of the pre-scrubbed FB memory on Ada is 256MB. When allocating
> + * a GSP WPR2 heap larger than 256MB, the scrubber ucode image is required
> + * to be exeucted before executing any other ucode images. Or, GSP
> + * firmware hangs when booting.
> + *
> + * The large GSP WPR2 heap is required especially by vGPU when supporting
> + * max vGPU count. The required size on Ada is at least 549MB.
> + */

Thanks for adding this, forget my comment from patch 6 then.

Do we expect this only to be a thing for Ada? If something similar is needed for
Blackwell too, we should probably generalize the code?

> +
>  static bool is_scrubber_completed(struct nvkm_gsp *gsp)
>  {
>  	return ((nvkm_rd32(gsp->subdev.device, 0x001180fc) >> 29) >= 0x3);
> -- 
> 2.34.1
>