drm/vc4: Convert existing documentation to actual kerneldoc.

I'm going to hook vc4 up to the sphinx build, so clean up its comments
to not generate warnings when we do.
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170227201144.10970-2-eric@anholt.net

drivers/gpu/drm/vc4/vc4_bo.c

@@ -6,7 +6,8 @@
  * published by the Free Software Foundation.
  */
 
-/* DOC: VC4 GEM BO management support.
+/**
+ * DOC: VC4 GEM BO management support
  *
  * The VC4 GPU architecture (both scanout and rendering) has direct
  * access to system memory with no MMU in between.  To support it, we
@@ -186,6 +187,8 @@ static struct vc4_bo *vc4_bo_get_from_cache(struct drm_device *dev,
 
 /**
  * vc4_gem_create_object - Implementation of driver->gem_create_object.
+ * @dev: DRM device
+ * @size: Size in bytes of the memory the object will reference
  *
  * This lets the CMA helpers allocate object structs for us, and keep
  * our BO stats correct.

drivers/gpu/drm/vc4/vc4_dsi.c

@@ -1453,8 +1453,9 @@ static irqreturn_t vc4_dsi_irq_handler(int irq, void *data)
 }
 
 /**
- * Exposes clocks generated by the analog PHY that are consumed by
- * CPRMAN (clk-bcm2835.c).
+ * vc4_dsi_init_phy_clocks - Exposes clocks generated by the analog
+ * PHY that are consumed by CPRMAN (clk-bcm2835.c).
+ * @dsi: DSI encoder
  */
 static int
 vc4_dsi_init_phy_clocks(struct vc4_dsi *dsi)

drivers/gpu/drm/vc4/vc4_gem.c

@@ -511,9 +511,18 @@ vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec)
 }
 
 /**
- * Looks up a bunch of GEM handles for BOs and stores the array for
- * use in the command validator that actually writes relocated
- * addresses pointing to them.
+ * vc4_cl_lookup_bos() - Sets up exec->bo[] with the GEM objects
+ * referenced by the job.
+ * @dev: DRM device
+ * @file_priv: DRM file for this fd
+ * @exec: V3D job being set up
+ *
+ * The command validator needs to reference BOs by their index within
+ * the submitted job's BO list.  This does the validation of the job's
+ * BO list and reference counting for the lifetime of the job.
+ *
+ * Note that this function doesn't need to unreference the BOs on
+ * failure, because that will happen at vc4_complete_exec() time.
  */
 static int
 vc4_cl_lookup_bos(struct drm_device *dev,
@@ -846,9 +855,16 @@ vc4_wait_bo_ioctl(struct drm_device *dev, void *data,
 }
 
 /**
- * Submits a command list to the VC4.
+ * vc4_submit_cl_ioctl() - Submits a job (frame) to the VC4.
+ * @dev: DRM device
+ * @data: ioctl argument
+ * @file_priv: DRM file for this fd
  *
- * This is what is called batchbuffer emitting on other hardware.
+ * This is the main entrypoint for userspace to submit a 3D frame to
+ * the GPU.  Userspace provides the binner command list (if
+ * applicable), and the kernel sets up the render command list to draw
+ * to the framebuffer described in the ioctl, using the command lists
+ * that the 3D engine's binner will produce.
  */
 int
 vc4_submit_cl_ioctl(struct drm_device *dev, void *data,

drivers/gpu/drm/vc4/vc4_irq.c

@@ -21,7 +21,8 @@
  * IN THE SOFTWARE.
  */
 
-/** DOC: Interrupt management for the V3D engine.
+/**
+ * DOC: Interrupt management for the V3D engine
  *
  * We have an interrupt status register (V3D_INTCTL) which reports
  * interrupts, and where writing 1 bits clears those interrupts.

drivers/gpu/drm/vc4/vc4_validate.c

@@ -22,7 +22,7 @@
  */
 
 /**
- * Command list validator for VC4.
+ * DOC: Command list validator for VC4.
  *
  * The VC4 has no IOMMU between it and system memory.  So, a user with
  * access to execute command lists could escalate privilege by
@@ -84,8 +84,12 @@ utile_height(int cpp)
 }
 
 /**
- * The texture unit decides what tiling format a particular miplevel is using
- * this function, so we lay out our miptrees accordingly.
+ * size_is_lt() - Returns whether a miplevel of the given size will
+ * use the lineartile (LT) tiling layout rather than the normal T
+ * tiling layout.
+ * @width: Width in pixels of the miplevel
+ * @height: Height in pixels of the miplevel
+ * @cpp: Bytes per pixel of the pixel format
  */
 static bool
 size_is_lt(uint32_t width, uint32_t height, int cpp)