From 30c57f0f1616e42d12c5c0bf138282e308d4bd40 Mon Sep 17 00:00:00 2001
From: Thierry Reding <treding@nvidia.com>
Date: Mon, 9 Dec 2019 13:00:02 +0100
Subject: drm/nouveau/tegra: Set clock rate if not set
Git-commit: fc12262b96833ce131063c7081cd7fb3c4a048f3
Patch-mainline: v5.6-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

If the GPU clock has not had a rate set, initialize it to the maximum
clock rate to make sure it does run.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
index 747a775121cf..d0d52c1d4aee 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
@@ -279,6 +279,7 @@ nvkm_device_tegra_new(const struct nvkm_device_tegra_func *func,
 		      struct nvkm_device **pdevice)
 {
 	struct nvkm_device_tegra *tdev;
+	unsigned long rate;
 	int ret;
 
 	if (!(tdev = kzalloc(sizeof(*tdev), GFP_KERNEL)))
@@ -307,6 +308,17 @@ nvkm_device_tegra_new(const struct nvkm_device_tegra_func *func,
 		goto free;
 	}
 
+	rate = clk_get_rate(tdev->clk);
+	if (rate == 0) {
+		ret = clk_set_rate(tdev->clk, ULONG_MAX);
+		if (ret < 0)
+			goto free;
+
+		rate = clk_get_rate(tdev->clk);
+
+		dev_dbg(&pdev->dev, "GPU clock set to %lu\n", rate);
+	}
+
 	if (func->require_ref_clk)
 		tdev->clk_ref = devm_clk_get(&pdev->dev, "ref");
 	if (IS_ERR(tdev->clk_ref)) {
-- 
2.28.0