[PATCH 06/10] drm/amdgpu: add amdgpu_gmc_agp_location

[Felix Kuehling]

On 2018-08-27 12:53 PM, Christian König wrote:
> Helper to figure out the location of the AGP BAR.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c | 42 +++++++++++++++++++++++++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h |  5 +++
>  2 files changed, 47 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> index 4331a0e25cdc..eed5352f3136 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> @@ -141,3 +141,45 @@ void amdgpu_gmc_gart_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc)
>  	dev_info(adev->dev, "GART: %lluM 0x%016llX - 0x%016llX\n",
>  			mc->gart_size >> 20, mc->gart_start, mc->gart_end);
>  }
> +
> +/**
> + * amdgpu_gmc_agp_location - try to find AGP location
> + * @adev: amdgpu device structure holding all necessary informations
> + * @mc: memory controller structure holding memory informations
> + *
> + * Function will place try to fina a place for the AGP BAR in the MC address

s/fina/find

> + * space.
> + *
> + * AGP BAR will be assigned the largest available hole in the address space.

I'd add a comment that this function must be called after
amdgpu_gmc_vram_location and amdgpu_gmc_gart_location.

> + */
> +void amdgpu_gmc_agp_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc)
> +{
> +	const uint64_t sixteen_gb = 1ULL << 34;
> +	u64 size_af, size_bf;
> +
> +	if (mc->vram_start > mc->gart_start) {
> +		size_bf = mc->vram_start - mc->gart_end + 1;
> +		size_af = mc->mc_mask - mc->vram_end;
> +	} else {
> +		size_bf = mc->vram_start;
> +		size_af = mc->mc_mask - mc->gart_end;
> +	}
> +
> +	size_bf &= ~(sixteen_gb - 1);
> +	size_af &= ~(sixteen_gb - 1);

This is not correct. E.g. vram_end  = 12GB, gart_start = 28GB, size =
16GB. agp_start will be rounded up to 16GB and AGP will run into the
GART aperture.

You need to align the addresses before calculating the sizes.

Regards,
  Felix

> +
> +	if (size_bf > size_af) {
> +		mc->agp_start = mc->vram_start > mc->gart_start ?
> +			mc->gart_start : 0;
> +		mc->agp_size = size_bf;
> +	} else {
> +		mc->agp_start = (mc->vram_start > mc->gart_start ?
> +			mc->vram_end : mc->gart_end) + 1,
> +		mc->agp_size = size_af;
> +	}
> +
> +	mc->agp_start = ALIGN(mc->agp_start, sixteen_gb);
> +	mc->agp_end = mc->agp_start + mc->agp_size - 1;
> +	dev_info(adev->dev, "AGP: %lluM 0x%016llX - 0x%016llX\n",
> +			mc->agp_size >> 20, mc->agp_start, mc->agp_end);
> +}
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> index 72fcc9338f5e..163110fe375d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> @@ -81,6 +81,9 @@ struct amdgpu_gmc {
>  	 * about vram size near mc fb location */
>  	u64			mc_vram_size;
>  	u64			visible_vram_size;
> +	u64			agp_size;
> +	u64			agp_start;
> +	u64			agp_end;
>  	u64			gart_size;
>  	u64			gart_start;
>  	u64			gart_end;
> @@ -138,5 +141,7 @@ void amdgpu_gmc_vram_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc,
>  			      u64 base);
>  void amdgpu_gmc_gart_location(struct amdgpu_device *adev,
>  			      struct amdgpu_gmc *mc);
> +void amdgpu_gmc_agp_location(struct amdgpu_device *adev,
> +			     struct amdgpu_gmc *mc);
>  
>  #endif