Revert "gpu: nvgpu: cache gpu clk rate"

This reverts commit e9a6d179a42e ("gpu: nvgpu: cache gpu clk rate")

 - Real clock rate doesn't always equal clock rate requested by caller
 - call of clk_set_rate() and update of cached_rate are not atomic
 - Real root cause for Bug 2051688 is in bpmp and gboost design

Bug 2538692

Change-Id: I9248e0c69e2271ed2d0070587db59afa6f8160f2
Signed-off-by: Peng Liu <pengliu@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2109708
(cherry picked from commit cc70f89bb4efd106b81c2da5ecd6cbeb69c990d8)
Reviewed-on: https://git-master.nvidia.com/r/2113647
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Aaron Tian <atian@nvidia.com>
Tested-by: Aaron Tian <atian@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>

5 files changed, 9 insertions, 28 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/clk_gk20a.h b/drivers/gpu/nvgpu/gk20a/clk_gk20a.h
index d84e5969..03aa6ab7 100644
--- a/drivers/gpu/nvgpu/gk20a/clk_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/clk_gk20a.h
@@ -1,5 +1,5 @@
 /*
- * 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"),
@@ -96,9 +96,6 @@ struct clk_gk20a {
 #if defined(CONFIG_COMMON_CLK)
         struct clk *tegra_clk;
         struct clk_hw hw;
-
-        /* scaling rate */
-        unsigned long cached_rate;
 #endif
         struct pll gpc_pll;
         struct pll gpc_pll_last;
diff --git a/drivers/gpu/nvgpu/os/linux/clk.c b/drivers/gpu/nvgpu/os/linux/clk.c
index 36c13577..6575a037 100644
--- a/drivers/gpu/nvgpu/os/linux/clk.c
+++ b/drivers/gpu/nvgpu/os/linux/clk.c
@@ -1,7 +1,7 @@
 /*
  * Linux clock support
  *
- * Copyright (c) 2017-2018, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2017-2019, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -38,13 +38,9 @@ static unsigned long nvgpu_linux_clk_get_rate(struct gk20a *g, u32 api_domain)
         switch (api_domain) {
         case CTRL_CLK_DOMAIN_GPCCLK:
                 if (g->clk.tegra_clk)
-                        ret = g->clk.cached_rate ?
-                                g->clk.cached_rate :
-                                clk_get_rate(g->clk.tegra_clk);
+                        ret = clk_get_rate(g->clk.tegra_clk);
                 else
-                        ret = platform->cached_rate ?
-                                platform->cached_rate :
-                                clk_get_rate(platform->clk[0]);
+                        ret = clk_get_rate(platform->clk[0]);
                 break;
         case CTRL_CLK_DOMAIN_PWRCLK:
                 ret = clk_get_rate(platform->clk[1]);
@@ -66,15 +62,10 @@ static int nvgpu_linux_clk_set_rate(struct gk20a *g,
 
         switch (api_domain) {
         case CTRL_CLK_DOMAIN_GPCCLK:
-                if (g->clk.tegra_clk) {
+                if (g->clk.tegra_clk)
                         ret = clk_set_rate(g->clk.tegra_clk, rate);
-                        if (!ret)
-                                g->clk.cached_rate = rate;
-                } else {
+                else
                         ret = clk_set_rate(platform->clk[0], rate);
-                        if (!ret)
-                                platform->cached_rate = rate;
-                }
                 break;
         case CTRL_CLK_DOMAIN_PWRCLK:
                 ret = clk_set_rate(platform->clk[1], rate);
diff --git a/drivers/gpu/nvgpu/os/linux/platform_gk20a.h b/drivers/gpu/nvgpu/os/linux/platform_gk20a.h
index a19d0a7c..1331c941 100644
--- a/drivers/gpu/nvgpu/os/linux/platform_gk20a.h
+++ b/drivers/gpu/nvgpu/os/linux/platform_gk20a.h
@@ -1,7 +1,7 @@
 /*
  * GK20A Platform (SoC) Interface
  *
- * Copyright (c) 2014-2018, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2014-2019, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -271,9 +271,6 @@ struct gk20a_platform {
         /* stream id to use */
         u32 ltc_streamid;
 
-        /* scaling rate */
-        unsigned long cached_rate;
-
         /* synchronized access to platform->clk_get_freqs */
         struct nvgpu_mutex clk_get_freq_lock;
 };
diff --git a/drivers/gpu/nvgpu/os/linux/platform_gk20a_tegra.c b/drivers/gpu/nvgpu/os/linux/platform_gk20a_tegra.c
index 408e546f..6a453096 100644
--- a/drivers/gpu/nvgpu/os/linux/platform_gk20a_tegra.c
+++ b/drivers/gpu/nvgpu/os/linux/platform_gk20a_tegra.c
@@ -1,7 +1,7 @@
 /*
  * GK20A Tegra Platform Interface
  *
- * Copyright (c) 2014-2018, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2014-2019, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -497,8 +497,6 @@ static int gk20a_tegra_get_clocks(struct device *dev)
                 rate = clk_round_rate(c, rate);
                 clk_set_rate(c, rate);
                 platform->clk[i] = c;
-                if (i == 0)
-                        platform->cached_rate = rate;
         }
         platform->num_clks = i;
 
diff --git a/drivers/gpu/nvgpu/os/linux/platform_gp10b_tegra.c b/drivers/gpu/nvgpu/os/linux/platform_gp10b_tegra.c
index a8308496..c5527f2d 100644
--- a/drivers/gpu/nvgpu/os/linux/platform_gp10b_tegra.c
+++ b/drivers/gpu/nvgpu/os/linux/platform_gp10b_tegra.c
@@ -1,7 +1,7 @@
 /*
  * GP10B Tegra Platform Interface
  *
- * Copyright (c) 2014-2018, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2014-2019, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -95,8 +95,6 @@ int gp10b_tegra_get_clocks(struct device *dev)
                 } else {
                         clk_set_rate(c, rate);
                         platform->clk[i] = c;
-                        if (i == 0)
-                                platform->cached_rate = rate;
                 }
         }
         platform->num_clks = i;