drm/drm_ioctl.c: kerneldoc

As usual pull it into the drm docbook template, too. And again as
usual I've decided to only document stuff exported to drivers, so all
the old leftover markup from the shared drm repo days lost the magic
** signature.
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Documentation/DocBook/drm.tmpl

@@ -3689,6 +3689,7 @@ int num_ioctls;</synopsis>
 	  </itemizedlist>
 	</para>
       </para>
+!Edrivers/gpu/drm/drm_ioctl.c
     </sect2>
   </sect1>
   <sect1>

drivers/gpu/drm/drm_ioctl.c

@@ -40,7 +40,7 @@
 static int drm_version(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv);
 
-/**
+/*
  * Get the bus id.
  *
  * \param inode device inode.
@@ -75,7 +75,7 @@ drm_unset_busid(struct drm_device *dev,
 	master->unique_len = 0;
 }
 
-/**
+/*
  * Set the bus id.
  *
  * \param inode device inode.
@@ -149,7 +149,7 @@ static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
 	return 0;
 }
 
-/**
+/*
  * Get a mapping information.
  *
  * \param inode device inode.
@@ -201,7 +201,7 @@ static int drm_getmap(struct drm_device *dev, void *data,
 	return 0;
 }
 
-/**
+/*
  * Get client information.
  *
  * \param inode device inode.
@@ -244,7 +244,7 @@ static int drm_getclient(struct drm_device *dev, void *data,
 	}
 }
 
-/**
+/*
  * Get statistics information.
  *
  * \param inode device inode.
@@ -265,7 +265,7 @@ static int drm_getstats(struct drm_device *dev, void *data,
 	return 0;
 }
 
-/**
+/*
  * Get device/driver capabilities
  */
 static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
@@ -318,7 +318,7 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 	return 0;
 }
 
-/**
+/*
  * Set device/driver capabilities
  */
 static int
@@ -352,7 +352,7 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
 	return 0;
 }
 
-/**
+/*
  * Setversion ioctl.
  *
  * \param inode device inode.
@@ -406,7 +406,18 @@ static int drm_setversion(struct drm_device *dev, void *data, struct drm_file *f
 	return retcode;
 }
 
-/** No-op ioctl. */
+/**
+ * drm_noop - DRM no-op ioctl implemntation
+ * @dev: DRM device for the ioctl
+ * @data: data pointer for the ioctl
+ * @file_priv: DRM file for the ioctl call
+ *
+ * This no-op implementation for drm ioctls is useful for deprecated
+ * functionality where we can't return a failure code because existing userspace
+ * checks the result of the ioctl, but doesn't care about the action.
+ *
+ * Always returns successfully with 0.
+ */
 int drm_noop(struct drm_device *dev, void *data,
 	     struct drm_file *file_priv)
 {
@@ -415,6 +426,21 @@ int drm_noop(struct drm_device *dev, void *data,
 }
 EXPORT_SYMBOL(drm_noop);
 
+/**
+ * drm_invalid_op - DRM invalid ioctl implemntation
+ * @dev: DRM device for the ioctl
+ * @data: data pointer for the ioctl
+ * @file_priv: DRM file for the ioctl call
+ *
+ * This no-op implementation for drm ioctls is useful for deprecated
+ * functionality where we really don't want to allow userspace to call the ioctl
+ * any more. This is the case for old ums interfaces for drivers that
+ * transitioned to kms gradually and so kept the old legacy tables around. This
+ * only applies to radeon and i915 kms drivers, other drivers shouldn't need to
+ * use this function.
+ *
+ * Always fails with a return value of -EINVAL.
+ */
 int drm_invalid_op(struct drm_device *dev, void *data,
 		   struct drm_file *file_priv)
 {
@@ -422,7 +448,7 @@ int drm_invalid_op(struct drm_device *dev, void *data,
 }
 EXPORT_SYMBOL(drm_invalid_op);
 
-/**
+/*
  * Copy and IOCTL return string to user space
  */
 static int drm_copy_field(char __user *buf, size_t *buf_len, const char *value)
@@ -445,7 +471,7 @@ static int drm_copy_field(char __user *buf, size_t *buf_len, const char *value)
 	return 0;
 }
 
-/**
+/*
  * Get version information
  *
  * \param inode device inode.
@@ -477,7 +503,7 @@ static int drm_version(struct drm_device *dev, void *data,
 	return err;
 }
 
-/**
+/*
  * drm_ioctl_permit - Check ioctl permissions against caller
  *
  * @flags: ioctl permission flags.
@@ -525,7 +551,7 @@ EXPORT_SYMBOL(drm_ioctl_permit);
 		.name = #ioctl			\
 	}
 
-/** Ioctl table */
+/* Ioctl table */
 static const struct drm_ioctl_desc drm_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version,
 		      DRM_UNLOCKED|DRM_RENDER_ALLOW|DRM_CONTROL_ALLOW),
@@ -642,16 +668,16 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
 #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )
 
 /**
- * Called whenever a process performs an ioctl on /dev/drm.
- *
- * \param inode device inode.
- * \param file_priv DRM file private.
- * \param cmd command.
- * \param arg user argument.
- * \return zero on success or negative number on failure.
+ * drm_ioctl - ioctl callback implementation for DRM drivers
+ * @filp: file this ioctl is called on
+ * @cmd: ioctl cmd number
+ * @arg: user argument
  *
  * Looks up the ioctl function in the ::ioctls table, checking for root
  * previleges if so required, and dispatches to the respective function.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
  */
 long drm_ioctl(struct file *filp,
 	      unsigned int cmd, unsigned long arg)
@@ -761,9 +787,15 @@ EXPORT_SYMBOL(drm_ioctl);
 
 /**
  * drm_ioctl_flags - Check for core ioctl and return ioctl permission flags
+ * @nr: ioctl number
+ * @flags: where to return the ioctl permission flags
+ *
+ * This ioctl is only used by the vmwgfx driver to augment the access checks
+ * done by the drm core and insofar a pretty decent layering violation. This
+ * shouldn't be used by any drivers.
  *
- * @nr: Ioctl number.
- * @flags: Where to return the ioctl permission flags
+ * Returns:
+ * True if the @nr corresponds to a DRM core ioctl numer, false otherwise.
  */
 bool drm_ioctl_flags(unsigned int nr, unsigned int *flags)
 {