[PATCH 1/2] drm/amdgpu: fix build up and tear down of debug vram access bounce buffer

[Chen, Guchun]

[Public]

Thanks for your quick fix, Jonathan.

I wonder if it's better to encapsulate the bo creation into a function and put the function definition in amdgpu_sdma or amdgpu_ttm?

Regards,
Guchun

-----Original Message-----
From: Kim, Jonathan <Jonathan.Kim at amd.com> 
Sent: Tuesday, January 18, 2022 7:43 AM
To: amd-gfx at lists.freedesktop.org
Cc: Kuehling, Felix <Felix.Kuehling at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>; Chen, Guchun <Guchun.Chen at amd.com>; Kim, Jonathan <Jonathan.Kim at amd.com>
Subject: [PATCH 1/2] drm/amdgpu: fix build up and tear down of debug vram access bounce buffer

Move the debug sdma vram bounce buffer GART map on device init after when GART is ready to avoid warnings and non-access to SDMA.

Also move bounce buffer tear down after the memory manager has flushed queued work for safety.

Signed-off-by: Jonathan Kim <jonathan.kim at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 11 +++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    |  8 --------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index da3348fa7b0e..099460d15258 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2378,6 +2378,13 @@ static int amdgpu_device_ip_init(struct amdgpu_device *adev)
 	if (r)
 		goto init_failed;
 
+	/* GTT bounce buffer for debug vram access over sdma. */
+	if (amdgpu_bo_create_kernel(adev, PAGE_SIZE, PAGE_SIZE,
+				AMDGPU_GEM_DOMAIN_GTT,
+				&adev->mman.sdma_access_bo, NULL,
+				&adev->mman.sdma_access_ptr))
+		DRM_WARN("Debug VRAM access will use slowpath MM access\n");
+
 	/*
 	 * retired pages will be loaded from eeprom and reserved here,
 	 * it should be called after amdgpu_device_ip_hw_init_phase2  since @@ -3872,6 +3879,10 @@ void amdgpu_device_fini_hw(struct amdgpu_device *adev)
 	}
 	adev->shutdown = true;
 
+	/* remove debug vram sdma access bounce buffer. */
+	amdgpu_bo_free_kernel(&adev->mman.sdma_access_bo, NULL,
+					&adev->mman.sdma_access_ptr);
+
 	/* make sure IB test finished before entering exclusive mode
 	 * to avoid preemption on IB test
 	 * */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index b489cd8abe31..6178ae7ba624 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1855,12 +1855,6 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
 		return r;
 	}
 
-	if (amdgpu_bo_create_kernel(adev, PAGE_SIZE, PAGE_SIZE,
-				AMDGPU_GEM_DOMAIN_GTT,
-				&adev->mman.sdma_access_bo, NULL,
-				adev->mman.sdma_access_ptr))
-		DRM_WARN("Debug VRAM access will use slowpath MM access\n");
-
 	return 0;
 }
 
@@ -1901,8 +1895,6 @@ void amdgpu_ttm_fini(struct amdgpu_device *adev)
 	ttm_range_man_fini(&adev->mman.bdev, AMDGPU_PL_OA);
 	ttm_device_fini(&adev->mman.bdev);
 	adev->mman.initialized = false;
-	amdgpu_bo_free_kernel(&adev->mman.sdma_access_bo, NULL,
-					&adev->mman.sdma_access_ptr);
 	DRM_INFO("amdgpu: ttm finalized\n");
 }
 
--
2.25.1