gpu: nvgpu: Add knob to control dbg/prof support

On production boards, there is requirement to disable GPU
profiler and debugger support. Add DT property 'support-gpu-tools'
which can be modified to enable/disable debugger/profiler support.
The default behavior is to enable the debugging features and set
'support-gpu-tools' to 1. This property is chosen to be u32 value
to be in sync with GPU vserser property by same name.
The debugger/profiler support is disabled by skipping the creation
of below nodes under /dev/nvgpu/:
1. ctxsw
2. dbg
3. prof
4. prof-dev
5. prof-ctx

Bug 200773450
JIRA NVGPU-7109

Change-Id: I86d72d17fa7f5492e117a4c1cd1144623e9b6132
Signed-off-by: Tejal Kudav <tkudav@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2592012
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit

drivers/gpu/nvgpu/include/nvgpu/gk20a.h

@@ -851,6 +851,9 @@ struct gk20a {
 
 	/** To enable emulate mode */
 	u32 emulate_mode;
+
+	/** Flag to check if debugger and profiler support is enabled. */
+	u32 support_gpu_tools;
 };
 
 /**

drivers/gpu/nvgpu/os/linux/driver_common.c

@@ -49,6 +49,28 @@ void nvgpu_kernel_restart(void *cmd)
 	kernel_restart(cmd);
 }
 
+void nvgpu_read_support_gpu_tools(struct gk20a *g)
+{
+	struct device_node *np;
+	int ret = 0;
+	u32 val = 0;
+
+	np = nvgpu_get_node(g);
+	ret = of_property_read_u32(np, "support-gpu-tools", &val);
+	if (ret != 0) {
+		nvgpu_info(g, "Missing support-gpu-tools property, ret =%d", ret);
+		/* The debugger/profiler support should be enabled by default.
+		 * So, set support_gpu_tools to 1 even if the property is missing. */
+		g->support_gpu_tools = 1;
+	} else {
+		if (val != 0U) {
+			g->support_gpu_tools = 1;
+		} else {
+			g->support_gpu_tools = 0;
+		}
+	}
+}
+
 static void nvgpu_init_vars(struct gk20a *g)
 {
 	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
@@ -320,6 +342,11 @@ int nvgpu_probe(struct gk20a *g,
 		return err;
 	}
 
+	/* Read the DT 'support-gpu-tools' property before creating
+	 * user nodes (via gk20a_user_nodes_init().
+	 */
+	nvgpu_read_support_gpu_tools(g);
+
 	/*
 	* TODO: While removing the legacy nodes the following condition
 	* need to be removed.

drivers/gpu/nvgpu/os/linux/driver_common.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2017, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2016-2021, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -23,5 +23,6 @@ int nvgpu_probe(struct gk20a *g,
 		const char *debugfs_symlink);
 
 void nvgpu_init_gk20a(struct gk20a *g);
+void nvgpu_read_support_gpu_tools(struct gk20a *g);
 
 #endif

drivers/gpu/nvgpu/os/linux/ioctl.c

@@ -168,22 +168,24 @@ struct nvgpu_dev_node {
 	const struct file_operations *fops;
 	/* If node should be created for physical instance in MIG mode */
 	bool mig_physical_node;
+	/* Flag to check if node is used by debugger/profiler. */
+	bool tools_node;
 };
 
 static const struct nvgpu_dev_node dev_node_list[] = {
-	{"power",	&gk20a_power_node_ops,	false   },
+	{"power",	&gk20a_power_node_ops,	false,	false   },
-	{"as",		&gk20a_as_ops,		false	},
+	{"as",		&gk20a_as_ops,		false,	false	},
-	{"channel",	&gk20a_channel_ops,	false	},
+	{"channel",	&gk20a_channel_ops,	false,	false	},
-	{"ctrl",	&gk20a_ctrl_ops,	true	},
+	{"ctrl",	&gk20a_ctrl_ops,	true,	false	},
 #if defined(CONFIG_NVGPU_FECS_TRACE)
-	{"ctxsw",	&gk20a_ctxsw_ops,	false	},
+	{"ctxsw",	&gk20a_ctxsw_ops,	false,	true	},
 #endif
-	{"dbg",		&gk20a_dbg_ops,		false	},
+	{"dbg",		&gk20a_dbg_ops,		false,	true	},
-	{"prof",	&gk20a_prof_ops,	false	},
+	{"prof",	&gk20a_prof_ops,	false,	true	},
-	{"prof-ctx",	&gk20a_prof_ctx_ops,	false	},
+	{"prof-ctx",	&gk20a_prof_ctx_ops,	false,	true	},
-	{"prof-dev",	&gk20a_prof_dev_ops,	false	},
+	{"prof-dev",	&gk20a_prof_dev_ops,	false,	true	},
-	{"sched",	&gk20a_sched_ops,	false	},
+	{"sched",	&gk20a_sched_ops,	false,	false	},
-	{"tsg",		&gk20a_tsg_ops,		false	},
+	{"tsg",		&gk20a_tsg_ops,		false,	false	},
 };
 
 static char *nvgpu_devnode(const char *cdev_name)
@@ -520,6 +522,12 @@ static bool check_valid_dev_node(struct gk20a *g, struct nvgpu_class *class,
 		}
 	}
 
+	/* Do not create nodes used by GPU tools if support for debugger
+	 * and profilers is disabled.
+	 */
+	if ((!g->support_gpu_tools) && (node->tools_node)) {
+		return false;
+	}
 	return true;
 }
 

drivers/gpu/nvgpu/os/linux/vgpu/vgpu_linux.c

@@ -401,6 +401,8 @@ int vgpu_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	nvgpu_read_support_gpu_tools(gk20a);
+
 	vgpu_init_vars(gk20a, platform);
 
 	init_rwsem(&l->busy_lock);