gpu: nvgpu: gm20b: Require rework for DVFS and rg

Boards require a rework to make railgating and DVFS work realiably.
The information whether the board has been reworked or not will be
available on DTS.

This patch adds a DTS check to the GPU driver initialisation. If the
rework information is not available (or the rework has been marked as
disabled), railgating and DVFS are disabled.

Bug 1555485

Change-Id: Ie86fe35fb94377403472faffcbcaec645b6e40d9
Signed-off-by: Arto Merilainen <amerilainen@nvidia.com>
Reviewed-on: http://git-master/r/500218
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c b/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
index 5dd30e31..bbbbccb4 100644
--- a/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
+++ b/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
@@ -440,6 +440,18 @@ static int gk20a_tegra_probe(struct platform_device *dev)
                 *platform = t132_gk20a_tegra_platform;
         }
 
+        /* WAR for bug 1547668: Disable railgating and scaling irrespective of
+         * platform data if the rework has not been made. */
+
+        if (tegra_get_chipid() == TEGRA_CHIPID_TEGRA21) {
+                np = of_find_node_by_path("/gpu-dvfs-rework");
+                if (!(np && of_device_is_available(np))) {
+                        platform->can_railgate = false;
+                        platform->devfreq_governor = "";
+                        dev_warn(&dev->dev, "board does not support scaling or powergating");
+                }
+        }
+
         gk20a_tegra_get_clocks(dev);
 
         return 0;