gpu: nvgpu: fix DEVFREQ init on T210 K4.4

Devfreq and gpcclk require GPU v/f tables for registering correctly.
Fix this by deferring the nvgpu_probe if GPU-DVFS is not completely
initialized. Change applicable to kernels with Common Clock Framework
enabled.

Bug 200233943

Change-Id: I82dadc1b0970d47e839d6bec935330966402e93b
Signed-off-by: Srikar Srimath Tirumala <srikars@nvidia.com>
Reviewed-on: http://git-master/r/1280832
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c b/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
index 87c678ea..c18f0230 100644
--- a/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
+++ b/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
@@ -537,16 +537,16 @@ static int gm20b_tegra_unrailgate(struct device *dev)
         if (platform->is_fmodel)
                 return 0;
 
+#ifdef CONFIG_TEGRA_CLK_FRAMEWORK
         if (!platform->gpu_rail) {
                 platform->gpu_rail = tegra_dvfs_get_rail_by_name(GPU_RAIL_NAME);
                 if (IS_ERR_OR_NULL(platform->gpu_rail)) {
                         WARN(1, "No GPU regulator?\n");
                         return -EINVAL;
                 }
-#ifdef CONFIG_TEGRA_CLK_FRAMEWORK
                 first = true;
-#endif
         }
+#endif
 
         ret = tegra_dvfs_rail_power_up(platform->gpu_rail);
         if (ret)
@@ -799,6 +799,24 @@ static int gk20a_tegra_probe(struct device *dev)
         bool joint_xpu_rail = false;
         int ret;
 
+#ifdef CONFIG_COMMON_CLK
+        /* DVFS is not guaranteed to be initialized at the time of probe on
+         * kernels with Common Clock Framework enabled.
+         */
+        if (!platform->gpu_rail) {
+                platform->gpu_rail = tegra_dvfs_get_rail_by_name(GPU_RAIL_NAME);
+                if (!platform->gpu_rail) {
+                        gk20a_dbg_info("deferring probe no gpu_rail\n");
+                        return -EPROBE_DEFER;
+                }
+        }
+
+        if (!tegra_dvfs_is_rail_ready(platform->gpu_rail)) {
+                gk20a_dbg_info("deferring probe gpu_rail not ready\n");
+                return -EPROBE_DEFER;
+        }
+#endif
+
         host1x_ptr = of_get_property(np, "nvidia,host1x", NULL);
         if (host1x_ptr) {
                 struct device_node *host1x_node =