gpu: nvgpu: track dev nodes using dynamic linked list

Remove static dev node meta data from struct nvgpu_os_linux and replace
it by a dynamic list. Struct nvgpu_os_linux will only keep track of list
head and number of entries.

Add new structure nvgpu_cdev to store meta data of each dev node and
create/setup it dynamically in gk20a_user_init(). Once done, add the new
node under list head maintained in nvgpu_os_linux.

Add a static list dev_node_list[] that contains list of dev node names
and file operations. This static list is used to create nvgpu_cdev data
structures and to register new device nodes.

Update all dev node open file operations (e.g. gk20a_as_dev_open()) to
extract struct gk20a pointer from device pointer of dev node.
gk20a device is the parent of dev node device.

Jira NVGPU-5648

Change-Id: If070c3428afd6215e45b4919335d9f43e04c36f9
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2428500
Reviewed-by: automaticguardword <automaticguardword@nvidia.com>
Reviewed-by: Alex Waterman <alexw@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/os/linux/os_linux.h

@@ -73,6 +73,19 @@ struct dgpu_thermal_alert {
         u32 event_delay;
 };
 
+struct nvgpu_cdev {
+	struct cdev cdev;
+	struct device *node;
+	struct nvgpu_list_node list_entry;
+};
+
+static inline struct nvgpu_cdev *
+nvgpu_cdev_from_list_entry(struct nvgpu_list_node *node)
+{
+	return (struct nvgpu_cdev *)
+		((uintptr_t)node - offsetof(struct nvgpu_cdev, list_entry));
+};
+
 struct nvgpu_os_linux {
 	struct gk20a g;
 	struct device *dev;
@@ -80,55 +93,8 @@ struct nvgpu_os_linux {
 	struct nvgpu_interrupts interrupts;
 	struct class *devnode_class;
 
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} channel;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} ctrl;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} as_dev;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} dbg;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} prof;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} prof_dev;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} prof_ctx;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} tsg;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} ctxsw;
-
-	struct {
-		struct cdev cdev;
-		struct device *node;
-	} sched;
+	struct nvgpu_list_node cdev_list_head;
+	u32 num_cdevs;
 
 	dev_t cdev_region;