gpu: nvgpu: Update GM20b clock initialization

- Removed unnecessary static "initialized" variable (sw_ready flag is
  protecting from multiple initializations, anyway).
- Used max frequency at min voltage to set initial configuration of
  GPCPLL in both NA and non-NA mode. For backward compatibility made
  sure initial PLL output rate do not exceed 1/3 of VCO minimum.

Bug 1555318

Change-Id: If970c27442ea1109d4503a322998a6a26159c345
Signed-off-by: Alex Frid <afrid@nvidia.com>
Reviewed-on: http://git-master/r/552370
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

1 files changed, 17 insertions, 16 deletions

diff --git a/drivers/gpu/nvgpu/gm20b/clk_gm20b.c b/drivers/gpu/nvgpu/gm20b/clk_gm20b.c
index 6ee7dff9..fbdf9368 100644
--- a/drivers/gpu/nvgpu/gm20b/clk_gm20b.c
+++ b/drivers/gpu/nvgpu/gm20b/clk_gm20b.c
@@ -1065,7 +1065,7 @@ struct clk *gm20b_clk_get(struct gk20a *g)
 static int gm20b_init_clk_setup_sw(struct gk20a *g)
 {
         struct clk_gk20a *clk = &g->clk;
-        static int initialized;
+        unsigned long safe_rate;
         struct clk *ref;
         bool calibrated;
 
@@ -1103,30 +1103,28 @@ static int gm20b_init_clk_setup_sw(struct gk20a *g)
         clk->gpc_pll.id = GK20A_GPC_PLL;
         clk->gpc_pll.clk_in = clk_get_rate(ref) / KHZ;
 
+        safe_rate = tegra_dvfs_get_therm_safe_fmax(
+                clk_get_parent(clk->tegra_clk));
+        safe_rate = safe_rate * (100 - DVFS_SAFE_MARGIN) / 100;
+        dvfs_safe_max_freq = rate_gpu_to_gpc2clk(safe_rate);
+        clk->gpc_pll.PL = DIV_ROUND_UP(gpc_pll_params.min_vco,
+                                       dvfs_safe_max_freq);
+
         /* Initial frequency: 1/3 VCO min (low enough to be safe at Vmin) */
-        if (!initialized) {
-                initialized = 1;
-                clk->gpc_pll.M = 1;
-                clk->gpc_pll.N = DIV_ROUND_UP(gpc_pll_params.min_vco,
-                                        clk->gpc_pll.clk_in);
-                clk->gpc_pll.PL = 3;
-                clk->gpc_pll.freq = clk->gpc_pll.clk_in * clk->gpc_pll.N;
-                clk->gpc_pll.freq /= pl_to_div(clk->gpc_pll.PL);
-        }
+        clk->gpc_pll.M = 1;
+        clk->gpc_pll.N = DIV_ROUND_UP(gpc_pll_params.min_vco,
+                                clk->gpc_pll.clk_in);
+        clk->gpc_pll.PL = max(clk->gpc_pll.PL, 3U);
+        clk->gpc_pll.freq = clk->gpc_pll.clk_in * clk->gpc_pll.N;
+        clk->gpc_pll.freq /= pl_to_div(clk->gpc_pll.PL);
 
         calibrated = !clk_config_calibration_params(g);
 #ifdef CONFIG_TEGRA_USE_NA_GPCPLL
         if (ALLOW_NON_CALIBRATED_NA_MODE || calibrated) {
                 /* NA mode is supported only at max update rate 38.4 MHz */
                 if (clk->gpc_pll.clk_in == gpc_pll_params.max_u) {
-                        unsigned long safe_rate;
                         clk->gpc_pll.mode = GPC_PLL_MODE_DVFS;
                         gpc_pll_params.min_u = gpc_pll_params.max_u;
-
-                        safe_rate = tegra_dvfs_get_therm_safe_fmax(
-                                clk_get_parent(clk->tegra_clk));
-                        safe_rate = safe_rate * (100 - DVFS_SAFE_MARGIN) / 100;
-                        dvfs_safe_max_freq = rate_gpu_to_gpc2clk(safe_rate);
                 }
         }
 #endif
@@ -1136,6 +1134,9 @@ static int gm20b_init_clk_setup_sw(struct gk20a *g)
         clk->sw_ready = true;
 
         gk20a_dbg_fn("done");
+        pr_info("GM20b GPCPLL initial settings:%s M=%u, N=%u, P=%u\n",
+                clk->gpc_pll.mode == GPC_PLL_MODE_DVFS ? " NA mode," : "",
+                clk->gpc_pll.M, clk->gpc_pll.N, clk->gpc_pll.PL);
         return 0;
 }