gpu: nvgpu: move syncpt documentation to doxygen

Sync/syncpt documentation was not in doxygen format.
Added doxygen syntax for proper parsing.

Jira NVGPU-4291

Change-Id: I6ad6eae1b02d88d97e241798838fa75da727ade2
Signed-off-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2236898
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Philip Elcan <pelcan@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vinod Gopalakrishnakurup <vinodg@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/include/nvgpu/channel_sync.h

@@ -87,27 +87,53 @@ void nvgpu_channel_sync_get_ref(struct nvgpu_channel_sync *s);
 bool nvgpu_channel_sync_put_ref_and_check(struct nvgpu_channel_sync *s);
 #endif /* CONFIG_NVGPU_KERNEL_MODE_SUBMIT */
 
-/*
- * Set the channel syncpoint/semaphore to safe state
+/**
+ * @brief Set the channel syncpoint/semaphore to safe state
+ *
+ * @param sync [in]	Pointer to syncpoint/semaphore.
+ *
  * This should be used to reset User managed syncpoint since we don't
  * track threshold values for those syncpoints
  */
 void nvgpu_channel_sync_set_safe_state(struct nvgpu_channel_sync *s);
 
-/*
+/**
+ * @brief Free channel syncpoint/semaphore
+ *
+ * @param sync [in]	Pointer to syncpoint/semaphore.
+ *
  * Free the resources allocated by nvgpu_channel_sync_create.
  */
 void nvgpu_channel_sync_destroy(struct nvgpu_channel_sync *sync,
 	bool set_safe_state);
 
-/*
+/**
+ * @brief Create channel syncpoint/semaphore
+ *
+ * @param c [in]		Pointer to Channel.
+ * @param user_managed [in]	True is syncpoint is user managed.
+ *
  * Construct a channel_sync backed by either a syncpoint or a semaphore.
  * A channel_sync is by default constructed as backed by a syncpoint
  * if CONFIG_TEGRA_GK20A_NVHOST is defined, otherwise the channel_sync
  * is constructed as backed by a semaphore.
+ *
+ * @return Pointer to nvgpu_channel_sync in case of success, or NULL
+ * in case of failure.
  */
 struct nvgpu_channel_sync *nvgpu_channel_sync_create(struct nvgpu_channel *c,
 	bool user_managed);
+
+/**
+ * @brief Check if OS fence framwework is needed
+ *
+ * @param g [in]		Pointer to GPU
+ *
+ * Sync framework requires deferred job cleanup, wrapping syncs in FDs,
+ * and other heavy stuff, which prevents deterministic submits.
+ *
+ * @return True is OS fence framework is needed.
+ */
 bool nvgpu_channel_sync_needs_os_fence_framework(struct gk20a *g);
 
 #endif /* NVGPU_CHANNEL_SYNC_H */

drivers/gpu/nvgpu/include/nvgpu/channel_sync_syncpt.h

@@ -39,13 +39,24 @@ struct priv_cmd_entry;
 
 #ifdef CONFIG_TEGRA_GK20A_NVHOST
 
-/*
- * Returns the sync point id or negative number if no syncpt
+/**
+ * @brief Get syncpoint id
+ *
+ * @param s [in]	Syncpoint pointer.
+ *
+ * @return Syncpoint id of \a s.
  */
 u32 nvgpu_channel_sync_get_syncpt_id(struct nvgpu_channel_sync_syncpt *s);
 
-/*
- * Returns the sync point address of sync point or 0 if not supported
+/**
+ * @brief Get syncpoint address
+ *
+ * @param s [in]	Syncpoint pointer.
+ *
+ * Get syncpoint GPU VA. This address can be used in push buffer entries
+ * for acquire/release operations.
+ *
+ * @return Syncpoint address (GPU VA) of syncpoint or 0 if not supported
  */
 u64 nvgpu_channel_sync_get_syncpt_address(struct nvgpu_channel_sync_syncpt *s);
 
@@ -58,16 +69,29 @@ int nvgpu_channel_sync_wait_syncpt(struct nvgpu_channel_sync_syncpt *s,
 	u32 id, u32 thresh, struct priv_cmd_entry *entry);
 #endif
 
-/*
- * Converts a valid struct nvgpu_channel_sync ptr to
- * struct nvgpu_channel_sync_syncpt ptr else return NULL.
+/**
+ * @brief Get syncpoint from sync operations
+ *
+ * @param sync [in]	Pointer to sync operations.
+ *
+ * Converts a valid struct nvgpu_channel_sync pointer \a sync to
+ * struct nvgpu_channel_sync_syncpt pointer else return NULL
+ *
+ * @return Pointer to syncpoint, if sync is backed by a syncpoint.
+ * @retval NULL if sync is backed by a sempahore.
  */
 struct nvgpu_channel_sync_syncpt *
 nvgpu_channel_sync_to_syncpt(struct nvgpu_channel_sync *sync);
 
-/*
- * Constructs a struct nvgpu_channel_sync_syncpt and returns a
- * pointer to the struct nvgpu_channel_sync associated with it.
+/**
+ * @brief Create syncpoint.
+ *
+ * @param c [in]		Pointer to channel.
+ * @param user_managed [in]	True is syncpoint is managed by client.
+ *
+ * Constructs a struct nvgpu_channel_sync_syncpt.
+ *
+ * @return Pointer to nvgpu_channel_sync associated with created syncpoint.
  */
 struct nvgpu_channel_sync *
 nvgpu_channel_sync_syncpt_create(struct nvgpu_channel *c,

drivers/gpu/nvgpu/include/nvgpu/fifo.h

@@ -108,6 +108,8 @@
  * Sync
  * ----
  *
+ *   + include/nvgpu/channel_sync.h
+ *   + include/nvgpu/channel_sync_syncpt.h
  *   + include/nvgpu/gops_sync.h
  *
  * Usermode