[PATCH 1/3] drm/amdgpu: check if vram is lost

[Chunming Zhou]

bakup first 64 byte of gart table as reset magic, check if magic is same
after gpu hw reset.

Change-Id: I9a73720da4084ea8677c3031dfb62e8157ee5704
Signed-off-by: Chunming Zhou <David1.Zhou at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  2 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 26 +++++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index de08ff0..f9da215 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1502,6 +1502,7 @@ struct amdgpu_ssg {
 #endif
 };
 
+#define AMDGPU_RESET_MAGIC_NUM 64
 struct amdgpu_device {
 	struct device			*dev;
 	struct drm_device		*ddev;
@@ -1705,6 +1706,7 @@ struct amdgpu_device {
 
 	/* record hw reset is performed */
 	bool has_hw_reset;
+	u8				reset_magic[AMDGPU_RESET_MAGIC_NUM];
 
 };
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 0a31fb1..58af9ea 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1685,6 +1685,23 @@ static int amdgpu_init(struct amdgpu_device *adev)
 	return 0;
 }
 
+static void amdgpu_fill_reset_magic(struct amdgpu_device *adev)
+{
+	memcpy(adev->reset_magic, adev->gart.ptr, AMDGPU_RESET_MAGIC_NUM);
+}
+
+static bool amdgpu_check_vram_lost(struct amdgpu_device *adev)
+{
+	int i;
+
+	for (i = 0; i < AMDGPU_RESET_MAGIC_NUM; i++) {
+		if (*((u8 *)(adev->gart.ptr + i)) != adev->reset_magic[i])
+			return true;
+	}
+
+	return false;
+}
+
 static int amdgpu_late_init(struct amdgpu_device *adev)
 {
 	int i = 0, r;
@@ -1715,6 +1732,8 @@ static int amdgpu_late_init(struct amdgpu_device *adev)
 		}
 	}
 
+	amdgpu_fill_reset_magic(adev);
+
 	return 0;
 }
 
@@ -2830,7 +2849,7 @@ int amdgpu_gpu_reset(struct amdgpu_device *adev)
 	struct drm_atomic_state *state = NULL;
 	int i, r;
 	int resched;
-	bool need_full_reset;
+	bool need_full_reset, vram_lost = false;
 
 	if (amdgpu_sriov_vf(adev))
 		return amdgpu_sriov_gpu_reset(adev, true);
@@ -2899,12 +2918,17 @@ int amdgpu_gpu_reset(struct amdgpu_device *adev)
 			r = amdgpu_resume_phase1(adev);
 			if (r)
 				goto out;
+			vram_lost = amdgpu_check_vram_lost(adev);
+			if (vram_lost)
+				DRM_ERROR("VRAM is lost!\n");
 			r = amdgpu_ttm_recover_gart(adev);
 			if (r)
 				goto out;
 			r = amdgpu_resume_phase2(adev);
 			if (r)
 				goto out;
+			if (vram_lost)
+				amdgpu_fill_reset_magic(adev);
 		}
 	}
 out:
-- 
1.9.1