On 02.09.25 16:52, Srinivasan Shanmugam wrote: > Add mmio_remap bookkeeping to amdgpu_device and introduce > amdgpu_ttm_mmio_remap_bo_init()/fini() to manage a kernel-owned, > one-page (4K) BO in AMDGPU_GEM_DOMAIN_MMIO_REMAP. > > Bookkeeping: > - adev->rmmio_remap.bo : kernel-owned singleton BO > > The BO is allocated during TTM init when a remap bus address is available > (adev->rmmio_remap.bus_addr) and PAGE_SIZE <= AMDGPU_GPU_PAGE_SIZE (4K), > and freed during TTM fini. > > v2: > - Check mmio_remap bus address (adev->rmmio_remap.bus_addr) instead of > rmmio_base. (Alex) > - Skip quietly if PAGE_SIZE > AMDGPU_GPU_PAGE_SIZE or no bus address > (no warn). (Alex) > - Use `amdgpu_bo_create()` (not *_kernel) - Only with this The object > is stored in adev->mmio_remap.bo and will later be exposed to > userspace via a GEM handle. (Christian) > > v3: > - Remove obvious comment before amdgpu_ttm_mmio_remap_bo_fini() call. > (Alex) > > v4: > - Squash bookkeeping into this patch (Christian) > > Suggested-by: Christian König <[email protected]> > Suggested-by: Alex Deucher <[email protected]> > Signed-off-by: Srinivasan Shanmugam <[email protected]>
Reviewed-by: Christian König <[email protected]> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 + > drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 59 +++++++++++++++++++++++++ > 2 files changed, 60 insertions(+) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h > b/drivers/gpu/drm/amd/amdgpu/amdgpu.h > index ddd472e56f69..24501d3fbefe 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h > @@ -752,6 +752,7 @@ typedef void (*amdgpu_block_wreg_t)(struct > amdgpu_device*, uint32_t, uint32_t, u > struct amdgpu_mmio_remap { > u32 reg_offset; > resource_size_t bus_addr; > + struct amdgpu_bo *bo; > }; > > /* Define the HW IP blocks will be used in driver , add more if necessary */ > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > index 1a68ba17a62d..f38bc9542cd6 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > @@ -1854,6 +1854,59 @@ static void amdgpu_ttm_pools_fini(struct amdgpu_device > *adev) > adev->mman.ttm_pools = NULL; > } > > +/** > + * amdgpu_ttm_mmio_remap_bo_init - Allocate the singleton 4K MMIO_REMAP BO > + * @adev: amdgpu device > + * > + * Allocates a one-page (4K) GEM BO in AMDGPU_GEM_DOMAIN_MMIO_REMAP when the > + * hardware exposes a remap base (adev->rmmio_remap.bus_addr) and the host > + * PAGE_SIZE is <= AMDGPU_GPU_PAGE_SIZE (4K). The BO is created as a regular > + * GEM object (amdgpu_bo_create). > + * > + * Return: > + * * 0 on success or intentional skip (feature not present/unsupported) > + * * negative errno on allocation failure > + */ > +static int amdgpu_ttm_mmio_remap_bo_init(struct amdgpu_device *adev) > +{ > + struct amdgpu_bo_param bp; > + int r; > + > + /* Skip if HW doesn't expose remap, or if PAGE_SIZE > > AMDGPU_GPU_PAGE_SIZE (4K). */ > + if (!adev->rmmio_remap.bus_addr || PAGE_SIZE > AMDGPU_GPU_PAGE_SIZE) > + return 0; > + > + memset(&bp, 0, sizeof(bp)); > + > + /* Create exactly one GEM BO in the MMIO_REMAP domain. */ > + bp.type = ttm_bo_type_device; /* userspace-mappable GEM > */ > + bp.size = AMDGPU_GPU_PAGE_SIZE; /* 4K */ > + bp.byte_align = AMDGPU_GPU_PAGE_SIZE; > + bp.domain = AMDGPU_GEM_DOMAIN_MMIO_REMAP; > + bp.flags = 0; > + bp.resv = NULL; > + bp.bo_ptr_size = sizeof(struct amdgpu_bo); > + > + r = amdgpu_bo_create(adev, &bp, &adev->rmmio_remap.bo); > + if (r) > + return r; > + > + return 0; > +} > + > +/** > + * amdgpu_ttm_mmio_remap_bo_fini - Free the singleton MMIO_REMAP BO > + * @adev: amdgpu device > + * > + * Frees the kernel-owned MMIO_REMAP BO if it was allocated by > + * amdgpu_ttm_mmio_remap_bo_init(). > + */ > +static void amdgpu_ttm_mmio_remap_bo_fini(struct amdgpu_device *adev) > +{ > + amdgpu_bo_unref(&adev->rmmio_remap.bo); > + adev->rmmio_remap.bo = NULL; > +} > + > /* > * amdgpu_ttm_init - Init the memory management (ttm) as well as various > * gtt/vram related fields. > @@ -2028,6 +2081,11 @@ int amdgpu_ttm_init(struct amdgpu_device *adev) > return r; > } > > + /* Allocate the singleton MMIO_REMAP BO (4K) if supported */ > + r = amdgpu_ttm_mmio_remap_bo_init(adev); > + if (r) > + return r; > + > /* Initialize preemptible memory pool */ > r = amdgpu_preempt_mgr_init(adev); > if (r) { > @@ -2091,6 +2149,7 @@ void amdgpu_ttm_fini(struct amdgpu_device *adev) > amdgpu_bo_free_kernel(&adev->mman.sdma_access_bo, NULL, > &adev->mman.sdma_access_ptr); > > + amdgpu_ttm_mmio_remap_bo_fini(adev); > amdgpu_ttm_fw_reserve_vram_fini(adev); > amdgpu_ttm_drv_reserve_vram_fini(adev); >
