drm/doc: Improve ioctl/fops docs a bit more

I spotted a markup issue, plus adding the descriptions in drm_driver.
Plus a few more links while at it.

I'm still mildly unhappy with the split between fops and ioctls, but I
still think having the ioctls in the uapi chapter makes more sense. Oh
well ...

v2: Rebase.

v3: Move misplace hunk to the right patch.

Cc: Stefan Agner <stefan@agner.ch>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170531092045.3950-1-daniel.vetter@ffwll.ch

Documentation/gpu/drm-internals.rst

@@ -198,6 +198,8 @@ drivers.
 Open/Close, File Operations and IOCTLs
 ======================================
 
+.. _drm_driver_fops:
+
 File Operations
 ---------------
 

Documentation/gpu/drm-uapi.rst

@@ -160,6 +160,8 @@ other hand, a driver requires shared state between clients which is
 visible to user-space and accessible beyond open-file boundaries, they
 cannot support render nodes.
 
+.. _drm_driver_ioctl:
+
 IOCTL Support on Device Nodes
 =============================
 

drivers/gpu/drm/drm_file.c

@@ -75,7 +75,7 @@ DEFINE_MUTEX(drm_global_mutex);
  * for drivers which use the CMA GEM helpers it's drm_gem_cma_mmap().
  *
  * No other file operations are supported by the DRM userspace API. Overall the
- * following is an example #file_operations structure::
+ * following is an example &file_operations structure::
  *
  *     static const example_drm_fops = {
  *             .owner = THIS_MODULE,
@@ -92,6 +92,11 @@ DEFINE_MUTEX(drm_global_mutex);
  * For plain GEM based drivers there is the DEFINE_DRM_GEM_FOPS() macro, and for
  * CMA based drivers there is the DEFINE_DRM_GEM_CMA_FOPS() macro to make this
  * simpler.
+ *
+ * The driver's &file_operations must be stored in &drm_driver.fops.
+ *
+ * For driver-private IOCTL handling see the more detailed discussion in
+ * :ref:`IOCTL support in the userland interfaces chapter<drm_driver_ioctl>`.
  */
 
 static int drm_open_helper(struct file *filp, struct drm_minor *minor);

drivers/gpu/drm/drm_ioctl.c

@@ -683,7 +683,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
  * 
  * DRM driver private IOCTL must be in the range from DRM_COMMAND_BASE to
  * DRM_COMMAND_END. Finally you need an array of &struct drm_ioctl_desc to wire
- * up the handlers and set the access rights:
+ * up the handlers and set the access rights::
  *
  *     static const struct drm_ioctl_desc my_driver_ioctls[] = {
  *         DRM_IOCTL_DEF_DRV(MY_DRIVER_OPERATION, my_driver_operation,
@@ -692,6 +692,9 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
  *
  * And then assign this to the &drm_driver.ioctls field in your driver
  * structure.
+ *
+ * See the separate chapter on :ref:`file operations<drm_driver_fops>` for how
+ * the driver-specific IOCTLs are wired up.
  */
 
 /**

include/drm/drm_drv.h

@@ -515,8 +515,26 @@ struct drm_driver {
 	char *date;
 
 	u32 driver_features;
+
+	/**
+	 * @ioctls:
+	 *
+	 * Array of driver-private IOCTL description entries. See the chapter on
+	 * :ref:`IOCTL support in the userland interfaces
+	 * chapter<drm_driver_ioctl>` for the full details.
+	 */
+
 	const struct drm_ioctl_desc *ioctls;
+	/** @num_ioctls: Number of entries in @ioctls. */
 	int num_ioctls;
+
+	/**
+	 * @fops:
+	 *
+	 * File operations for the DRM device node. See the discussion in
+	 * :ref:`file operations<drm_driver_fops>` for in-depth coverage and
+	 * some examples.
+	 */
 	const struct file_operations *fops;
 
 	/* Everything below here is for legacy driver, never use! */