[PATCH 1/1] drm/amdgpu: pin the csb buffer on hw init for gfx v8

[Kai-Heng Feng]

From: Likun Gao <Likun.Gao at amd.com>

BugLink: https://bugs.launchpad.net/bugs/1833617

Without this pin, the csb buffer will be filled with inconsistent
data after S3 resume. And that will causes gfx hang on gfxoff
exit since this csb will be executed then.

Signed-off-by: Likun Gao <Likun.Gao at amd.com>
Tested-by: Paul Gover <pmw.gover at yahoo.co.uk>
Reviewed-by: Feifei Xu <Feifei.Xu at amd.com>
Reviewed-by: Xiaojie Yuan <xiaojie.yuan at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
(cherry picked from commit 72cda9bb5e219aea0f2f62f56ae05198c59022a7)
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
---
 drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c | 40 +++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
index 57cb3a51bda7..f558758f2dc1 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
@@ -1317,6 +1317,39 @@ static int gfx_v8_0_rlc_init(struct amdgpu_device *adev)
 	return 0;
 }
 
+static int gfx_v8_0_csb_vram_pin(struct amdgpu_device *adev)
+{
+	int r;
+
+	r = amdgpu_bo_reserve(adev->gfx.rlc.clear_state_obj, false);
+	if (unlikely(r != 0))
+		return r;
+
+	r = amdgpu_bo_pin(adev->gfx.rlc.clear_state_obj,
+			AMDGPU_GEM_DOMAIN_VRAM);
+	if (!r)
+		adev->gfx.rlc.clear_state_gpu_addr =
+			amdgpu_bo_gpu_offset(adev->gfx.rlc.clear_state_obj);
+
+	amdgpu_bo_unreserve(adev->gfx.rlc.clear_state_obj);
+
+	return r;
+}
+
+static void gfx_v8_0_csb_vram_unpin(struct amdgpu_device *adev)
+{
+	int r;
+
+	if (!adev->gfx.rlc.clear_state_obj)
+		return;
+
+	r = amdgpu_bo_reserve(adev->gfx.rlc.clear_state_obj, true);
+	if (likely(r == 0)) {
+		amdgpu_bo_unpin(adev->gfx.rlc.clear_state_obj);
+		amdgpu_bo_unreserve(adev->gfx.rlc.clear_state_obj);
+	}
+}
+
 static void gfx_v8_0_mec_fini(struct amdgpu_device *adev)
 {
 	amdgpu_bo_free_kernel(&adev->gfx.mec.hpd_eop_obj, NULL, NULL);
@@ -4776,6 +4809,10 @@ static int gfx_v8_0_hw_init(void *handle)
 	gfx_v8_0_init_golden_registers(adev);
 	gfx_v8_0_constants_init(adev);
 
+	r = gfx_v8_0_csb_vram_pin(adev);
+	if (r)
+		return r;
+
 	r = adev->gfx.rlc.funcs->resume(adev);
 	if (r)
 		return r;
@@ -4892,6 +4929,9 @@ static int gfx_v8_0_hw_fini(void *handle)
 	else
 		pr_err("rlc is busy, skip halt rlc\n");
 	amdgpu_gfx_rlc_exit_safe_mode(adev);
+
+	gfx_v8_0_csb_vram_unpin(adev);
+
 	return 0;
 }
 
-- 
2.17.1