On Sat, Aug 23, 2025 at 3:28 AM Srinivasan Shanmugam
<srinivasan.shanmu...@amd.com> wrote:
>
> Implement TTM-level behavior for AMDGPU_PL_MMIO_REMAP so it behaves as a
> CPU-visible IO page:
>
> * amdgpu_evict_flags(): mark as unmovable
> * amdgpu_res_cpu_visible(): consider CPU-visible
> * amdgpu_bo_move(): use null move when src/dst is MMIO_REMAP
> * amdgpu_ttm_io_mem_reserve(): program base/is_iomem/caching using
> the device's mmio_remap_* metadata
> * amdgpu_ttm_io_mem_pfn(): return PFN for the remapped HDP page
> * amdgpu_ttm_tt_pde_flags(): set AMDGPU_PTE_SYSTEM for this mem type
>
> v2:
> - Drop HDP-specific comment; keep generic remap (Alex).
> - Use adev->rmmio_base; remove base+offset math (Alex).
>
> Cc: Christian König <christian.koe...@amd.com>
> Suggested-by: Alex Deucher <alexander.deuc...@amd.com>
> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmu...@amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 27ab4e754b2a..f6027ccd9196 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -123,6 +123,7 @@ static void amdgpu_evict_flags(struct ttm_buffer_object
> *bo,
> case AMDGPU_PL_GWS:
> case AMDGPU_PL_OA:
> case AMDGPU_PL_DOORBELL:
> + case AMDGPU_PL_MMIO_REMAP:
> placement->num_placement = 0;
> return;
>
> @@ -447,7 +448,8 @@ bool amdgpu_res_cpu_visible(struct amdgpu_device *adev,
> return false;
>
> if (res->mem_type == TTM_PL_SYSTEM || res->mem_type == TTM_PL_TT ||
> - res->mem_type == AMDGPU_PL_PREEMPT || res->mem_type ==
> AMDGPU_PL_DOORBELL)
> + res->mem_type == AMDGPU_PL_PREEMPT || res->mem_type ==
> AMDGPU_PL_DOORBELL ||
> + res->mem_type == AMDGPU_PL_MMIO_REMAP)
> return true;
>
> if (res->mem_type != TTM_PL_VRAM)
> @@ -538,10 +540,12 @@ static int amdgpu_bo_move(struct ttm_buffer_object *bo,
> bool evict,
> old_mem->mem_type == AMDGPU_PL_GWS ||
> old_mem->mem_type == AMDGPU_PL_OA ||
> old_mem->mem_type == AMDGPU_PL_DOORBELL ||
> + old_mem->mem_type == AMDGPU_PL_MMIO_REMAP ||
> new_mem->mem_type == AMDGPU_PL_GDS ||
> new_mem->mem_type == AMDGPU_PL_GWS ||
> new_mem->mem_type == AMDGPU_PL_OA ||
> - new_mem->mem_type == AMDGPU_PL_DOORBELL) {
> + new_mem->mem_type == AMDGPU_PL_DOORBELL ||
> + new_mem->mem_type == AMDGPU_PL_MMIO_REMAP) {
> /* Nothing to save here */
> amdgpu_bo_move_notify(bo, evict, new_mem);
> ttm_bo_move_null(bo, new_mem);
> @@ -629,6 +633,12 @@ static int amdgpu_ttm_io_mem_reserve(struct ttm_device
> *bdev,
> mem->bus.is_iomem = true;
> mem->bus.caching = ttm_uncached;
> break;
> + case AMDGPU_PL_MMIO_REMAP:
> + mem->bus.offset = mem->start << PAGE_SHIFT;
> + mem->bus.offset += adev->rmmio_base;
This is wrong. It needs to be adev->rmmio_remap.bus_addr.
> + mem->bus.is_iomem = true;
> + mem->bus.caching = ttm_uncached;
> + break;
> default:
> return -EINVAL;
> }
> @@ -646,6 +656,8 @@ static unsigned long amdgpu_ttm_io_mem_pfn(struct
> ttm_buffer_object *bo,
>
> if (bo->resource->mem_type == AMDGPU_PL_DOORBELL)
> return ((uint64_t)(adev->doorbell.base + cursor.start)) >>
> PAGE_SHIFT;
> + else if (bo->resource->mem_type == AMDGPU_PL_MMIO_REMAP)
> + return ((uint64_t)(adev->rmmio_base + cursor.start)) >>
> PAGE_SHIFT;
Same here.
Alex
>
> return (adev->gmc.aper_base + cursor.start) >> PAGE_SHIFT;
> }
> @@ -1355,7 +1367,7 @@ uint64_t amdgpu_ttm_tt_pde_flags(struct ttm_tt *ttm,
> struct ttm_resource *mem)
>
> if (mem && (mem->mem_type == TTM_PL_TT ||
> mem->mem_type == AMDGPU_PL_DOORBELL ||
> - mem->mem_type == AMDGPU_PL_PREEMPT)) {
> + mem->mem_type == AMDGPU_PL_PREEMPT || mem->mem_type ==
> AMDGPU_PL_MMIO_REMAP)) {
> flags |= AMDGPU_PTE_SYSTEM;
>
> if (ttm->caching == ttm_cached)
> --
> 2.34.1
>
