gpu: nvgpu: add support for disabling l3 via DT

On volta the GPU determines whether to do L3 allocation for a mapping by
checking bit 36 of the physical address. So if a mapping should allocate lines
in the L3 this bit must be set.

However, when the physical addresses for 64GB of RAM uses the 36th bit
resulting in a conflict. Thus, add support for disabling l3 support
for SKUs having 64GB of physical memory.

Bug 3486025

Signed-off-by: Debarshi Dutta <ddutta@nvidia.com>
Change-Id: Ic540e754274cf1d9e6625493962699d21509e540
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2661548
Reviewed-by: Brad Griffis <bgriffis@nvidia.com>
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Tested-by: Brad Griffis <bgriffis@nvidia.com>
GVS: Gerrit_Virtual_Submit

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/include/nvgpu/enabled.h b/drivers/gpu/nvgpu/include/nvgpu/enabled.h
index ef55dad8..51e93586 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/enabled.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/enabled.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2017-2022, 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"),
@@ -85,7 +85,12 @@ struct gk20a;
 #define NVGPU_MM_USE_PHYSICAL_SG                27
 /* WAR for gm20b chips. */
 #define NVGPU_MM_FORCE_128K_PMU_VM              28
-
+/* SW ERRATA to disable L3 alloc Bit of the physical address.
+ * Bit number varies between SOCs.
+ * E.g. 64GB physical RAM support for gv11b requires this SW errata
+ * to be enabled.
+ */
+#define NVGPU_DISABLE_L3_SUPPORT                29
 /*
  * Host flags
  */