gpu: nvgpu: Add support for XPU rail split

Check if CPU/GPU rails are joint, disable railgating if they are.
Add the DT support for T194 and T186 platforms.

Disable railgate_enable sysfs node update in the above condition.

Bug 200546450
Bug 200545711

Change-Id: I002488f6418805569b0ef0fc3032b58297adeafb
Signed-off-by: Debarshi Dutta <ddutta@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2185221
Reviewed-by: Rajkumar Kasirajan <rkasirajan@nvidia.com>
Tested-by: Rajkumar Kasirajan <rkasirajan@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-by: Alex Waterman <alexw@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>

4 files changed, 34 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/os/linux/platform_gk20a_tegra.c b/drivers/gpu/nvgpu/os/linux/platform_gk20a_tegra.c
index 0977e63a..c39e4f0e 100644
--- a/drivers/gpu/nvgpu/os/linux/platform_gk20a_tegra.c
+++ b/drivers/gpu/nvgpu/os/linux/platform_gk20a_tegra.c
@@ -799,6 +799,7 @@ static int gk20a_tegra_probe(struct device *dev)
 
         if (joint_xpu_rail) {
                 nvgpu_log_info(g, "XPU rails are joint\n");
+                platform->can_railgate_init = false;
                 __nvgpu_set_enabled(g, NVGPU_CAN_RAILGATE, false);
         }
 
diff --git a/drivers/gpu/nvgpu/os/linux/platform_gp10b_tegra.c b/drivers/gpu/nvgpu/os/linux/platform_gp10b_tegra.c
index c5527f2d..9bf8d637 100644
--- a/drivers/gpu/nvgpu/os/linux/platform_gp10b_tegra.c
+++ b/drivers/gpu/nvgpu/os/linux/platform_gp10b_tegra.c
@@ -141,6 +141,8 @@ static void gp10b_tegra_scale_exit(struct device *dev)
 static int gp10b_tegra_probe(struct device *dev)
 {
         struct gk20a_platform *platform = dev_get_drvdata(dev);
+        bool joint_xpu_rail = false;
+        struct gk20a *g = platform->g;
 #ifdef CONFIG_TEGRA_GK20A_NVHOST
         int ret;
 
@@ -163,6 +165,17 @@ static int gp10b_tegra_probe(struct device *dev)
         platform->g->gr.ctx_vars.force_preemption_gfxp = false;
         platform->g->gr.ctx_vars.force_preemption_cilp = false;
 
+#ifdef CONFIG_OF
+        joint_xpu_rail = of_property_read_bool(of_chosen,
+                                "nvidia,tegra-joint_xpu_rail");
+#endif
+
+        if (joint_xpu_rail) {
+                nvgpu_log_info(g, "XPU rails are joint\n");
+                platform->can_railgate_init = false;
+                __nvgpu_set_enabled(g, NVGPU_CAN_RAILGATE, false);
+        }
+
         gp10b_tegra_get_clocks(dev);
         nvgpu_linux_init_clk_support(platform->g);
 
diff --git a/drivers/gpu/nvgpu/os/linux/platform_gv11b_tegra.c b/drivers/gpu/nvgpu/os/linux/platform_gv11b_tegra.c
index ac1958a2..6c9d0f5c 100644
--- a/drivers/gpu/nvgpu/os/linux/platform_gv11b_tegra.c
+++ b/drivers/gpu/nvgpu/os/linux/platform_gv11b_tegra.c
@@ -73,6 +73,8 @@ static int gv11b_tegra_probe(struct device *dev)
 {
         struct gk20a_platform *platform = dev_get_drvdata(dev);
         int err;
+        bool joint_xpu_rail = false;
+        struct gk20a *g = platform->g;
 
         err = nvgpu_nvhost_syncpt_init(platform->g);
         if (err) {
@@ -94,6 +96,17 @@ static int gv11b_tegra_probe(struct device *dev)
         platform->g->gr.ctx_vars.force_preemption_gfxp = false;
         platform->g->gr.ctx_vars.force_preemption_cilp = false;
 
+#ifdef CONFIG_OF
+        joint_xpu_rail = of_property_read_bool(of_chosen,
+                                "nvidia,tegra-joint_xpu_rail");
+#endif
+
+        if (joint_xpu_rail) {
+                nvgpu_log_info(g, "XPU rails are joint\n");
+                platform->can_railgate_init = false;
+                __nvgpu_set_enabled(g, NVGPU_CAN_RAILGATE, false);
+        }
+
         gp10b_tegra_get_clocks(dev);
         nvgpu_linux_init_clk_support(platform->g);
 
diff --git a/drivers/gpu/nvgpu/os/linux/sysfs.c b/drivers/gpu/nvgpu/os/linux/sysfs.c
index 2ab29649..84a311de 100644
--- a/drivers/gpu/nvgpu/os/linux/sysfs.c
+++ b/drivers/gpu/nvgpu/os/linux/sysfs.c
@@ -259,13 +259,19 @@ static ssize_t railgate_enable_store(struct device *dev,
         unsigned long railgate_enable = 0;
         /* dev is guaranteed to be valid here. Ok to de-reference */
         struct gk20a *g = get_gk20a(dev);
+        struct gk20a_platform *platform = dev_get_drvdata(dev);
         bool enabled = nvgpu_is_enabled(g, NVGPU_CAN_RAILGATE);
         int err;
 
         if (kstrtoul(buf, 10, &railgate_enable) < 0)
                 return -EINVAL;
 
-        if (railgate_enable && !enabled) {
+        if (!platform->can_railgate_init) {
+                nvgpu_err(g, "Railgating is not supported");
+                return -EINVAL;
+        }
+
+        if (railgate_enable) {
                 __nvgpu_set_enabled(g, NVGPU_CAN_RAILGATE, true);
                 pm_runtime_set_autosuspend_delay(dev, g->railgate_delay);
         } else if (railgate_enable == 0 && enabled) {