[RFC PATCH 2/7] drm/amdgpu: Add New TTM Placement - AMDGPU_PL_MMIO_REMAP and wire up plumbing

[Christian König]

On 20.08.25 13:32, Srinivasan Shanmugam wrote:
> Introduce a kernel-internal TTM placement type AMDGPU_PL_MMIO_REMAP
> for the HDP flush MMIO remap page
> 
> Plumbing added:
> - amdgpu_res_cursor.{first,next}: treat MMIO_REMAP like DOORBELL
> - amdgpu_ttm_io_mem_reserve(): return BAR bus address + offset
>   for MMIO_REMAP, mark as uncached I/O
> - amdgpu_ttm_io_mem_pfn(): PFN from register BAR
> - amdgpu_res_cpu_visible(): visible to CPU
> - amdgpu_evict_flags()/amdgpu_bo_move(): non-migratable
> - amdgpu_ttm_tt_pde_flags(): map as SYSTEM
> - amdgpu_bo_mem_stats_placement(): report AMDGPU_PL_MMIO_REMAP
> - amdgpu_fdinfo: print “mmioremap” bucket label
> 
> Notes:
> - This patch bumps __AMDGPU_PL_NUM and (for now) TTM_NUM_MEM_TYPES to
>   avoid compile-time guards.
> 
> Cc: Christian König <christian.koenig at amd.com>
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 3 ++-
>  include/drm/ttm/ttm_resource.h          | 2 +-
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> index 2309df3f68a9..bb17987f0447 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> @@ -34,7 +34,8 @@
>  #define AMDGPU_PL_OA		(TTM_PL_PRIV + 2)
>  #define AMDGPU_PL_PREEMPT	(TTM_PL_PRIV + 3)
>  #define AMDGPU_PL_DOORBELL	(TTM_PL_PRIV + 4)
> -#define __AMDGPU_PL_NUM	(TTM_PL_PRIV + 5)
> +#define AMDGPU_PL_MMIO_REMAP	(TTM_PL_PRIV + 5)
> +#define __AMDGPU_PL_NUM	(TTM_PL_PRIV + 6)
>  
>  #define AMDGPU_GTT_MAX_TRANSFER_SIZE	512
>  #define AMDGPU_GTT_NUM_TRANSFER_WINDOWS	2
> diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
> index e52bba15012f..f49daa504c36 100644
> --- a/include/drm/ttm/ttm_resource.h
> +++ b/include/drm/ttm/ttm_resource.h
> @@ -36,7 +36,7 @@
>  #include <drm/ttm/ttm_kmap_iter.h>
>  
>  #define TTM_MAX_BO_PRIORITY	4U
> -#define TTM_NUM_MEM_TYPES 8
> +#define TTM_NUM_MEM_TYPES 9

Please make that a separate patch.

Thanks,
Christian

>  
>  struct dmem_cgroup_device;
>  struct ttm_device;