gpu: nvgpu: re-enable elpg after golden img init

Typically, the PMU init thread will finish up long
before the golden context image has been initialized,
which means that ELPG hasn't truly been enabled at that
point.

Create a new function, nvgpu_pmu_reenable_pg(), which
checks if elpg had been enabled (non-zero refcnt), and
if so, disables then re-enables it.

Call this function from gk20a_alloc_obj_ctx() after
the golden context image has been initialized to ensure
that elpg is truly enabled.

Manually ported from dev-main

Bug 200543218

Change-Id: I0e7c4f64434c5e356829581950edce61cc88882a
Signed-off-by: Peter Daifuku <pdaifuku@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2245768
(cherry picked from commit 077b6712b5a40340ece818416002ac8431dc4138)
Reviewed-on: https://git-master.nvidia.com/r/2250091
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
index 4f8006b2..223937c6 100644
--- a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
@@ -1,7 +1,7 @@
 /*
  * GK20A Graphics
  *
- * Copyright (c) 2011-2018, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2011-2019, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -3128,7 +3128,7 @@ int gk20a_alloc_obj_ctx(struct channel_gk20a  *c, u32 class_num, u32 flags)
                         goto out;
                 }
 
-                /* init golden image, ELPG enabled after this is done */
+                /* init golden image */
                 err = gr_gk20a_init_golden_ctx_image(g, c);
                 if (err != 0) {
                         nvgpu_err(g,
@@ -3136,6 +3136,17 @@ int gk20a_alloc_obj_ctx(struct channel_gk20a  *c, u32 class_num, u32 flags)
                         goto out;
                 }
 
+                /* Re-enable ELPG now that golden image has been initialized.
+                 * The PMU PG init code may already have tried to enable elpg, but
+                 * would not have been able to complete this action since the golden
+                 * image hadn't been initialized yet, so do this now.
+                 */
+                err = nvgpu_pmu_reenable_elpg(g);
+                if (err != 0) {
+                        nvgpu_err(g, "fail to re-enable elpg");
+                        goto out;
+                }
+
                 /* load golden image */
                 gr_gk20a_load_golden_ctx_image(g, c);
                 if (err != 0) {