drm/amdgpu/ttm: Allocate/Free 4K MMIO_REMAP Singleton

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 <christian.koenig@amd.com>
Suggested-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 0e6a09651bbc6a51be0ac7b8399ddd6c146b5dd6..c56839528843591882965bf825ff133dcd7bc1e1 100644 (file)
--- 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 1a68ba17a62dd04c0d2ba043ce1aa4db78a7051b..f38bc9542cd6885fcb2e83d1246ab6f90abdee53 100644 (file)
--- 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);