From 2a7a794eb82c37014ea95f7f58ebeff73ef72858 Mon Sep 17 00:00:00 2001 From: Srinivasan Shanmugam Date: Thu, 28 Aug 2025 19:18:49 +0530 Subject: [PATCH 5142/5403] drm/amdgpu/ttm: Allocate/Free 4K MMIO_REMAP Singleton MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Suggested-by: Alex Deucher Signed-off-by: Srinivasan Shanmugam Reviewed-by: Christian König Signed-off-by: Alex Deucher --- 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 0e6a09651bbc..c56839528843 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); -- 2.54.0