drm/ttm: add drm gem ttm helpers, starting with drm_gem_ttm_print_info()

Now with ttm_buffer_object being a subclass of drm_gem_object we can
easily lookup ttm_buffer_object for a given drm_gem_object, which in
turn allows to create common helper functions.

This patch starts off with a drm_gem_ttm_print_info() helper function
which adds some ttm specific lines to the debug output.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190904054740.20817-3-kraxel@redhat.com

Documentation/gpu/drm-mm.rst

@@ -412,6 +412,18 @@ VRAM MM Helper Functions Reference
 .. kernel-doc:: drivers/gpu/drm/drm_vram_mm_helper.c
    :export:
 
+GEM TTM Helper Functions Reference
+-----------------------------------
+
+.. kernel-doc:: drivers/gpu/drm/drm_gem_ttm_helper.c
+   :doc: overview
+
+.. kernel-doc:: include/drm/drm_gem_ttm_helper.h
+   :internal:
+
+.. kernel-doc:: drivers/gpu/drm/drm_gem_ttm_helper.c
+   :export:
+
 VMA Offset Manager
 ==================
 

drivers/gpu/drm/Kconfig

@@ -172,6 +172,13 @@ config DRM_VRAM_HELPER
 	help
 	  Helpers for VRAM memory management
 
+config DRM_TTM_HELPER
+	tristate
+	depends on DRM
+	select DRM_TTM
+	help
+	  Helpers for ttm-based gem objects
+
 config DRM_GEM_CMA_HELPER
 	bool
 	depends on DRM

drivers/gpu/drm/Makefile

@@ -37,6 +37,9 @@ drm_vram_helper-y := drm_gem_vram_helper.o \
 		     drm_vram_mm_helper.o
 obj-$(CONFIG_DRM_VRAM_HELPER) += drm_vram_helper.o
 
+drm_ttm_helper-y := drm_gem_ttm_helper.o
+obj-$(CONFIG_DRM_TTM_HELPER) += drm_ttm_helper.o
+
 drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_dsc.o drm_probe_helper.o \
 		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
 		drm_kms_helper_common.o drm_dp_dual_mode_helper.o \

drivers/gpu/drm/drm_gem_ttm_helper.c

@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/module.h>
+
+#include <drm/drm_gem_ttm_helper.h>
+
+/**
+ * DOC: overview
+ *
+ * This library provides helper functions for gem objects backed by
+ * ttm.
+ */
+
+/**
+ * drm_gem_ttm_print_info() - Print &ttm_buffer_object info for debugfs
+ * @p: DRM printer
+ * @indent: Tab indentation level
+ * @gem: GEM object
+ *
+ * This function can be used as &drm_gem_object_funcs.print_info
+ * callback.
+ */
+void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
+			    const struct drm_gem_object *gem)
+{
+	static const char const *plname[] = {
+		[ TTM_PL_SYSTEM ] = "system",
+		[ TTM_PL_TT     ] = "tt",
+		[ TTM_PL_VRAM   ] = "vram",
+		[ TTM_PL_PRIV   ] = "priv",
+
+		[ 16 ]            = "cached",
+		[ 17 ]            = "uncached",
+		[ 18 ]            = "wc",
+		[ 19 ]            = "contig",
+
+		[ 21 ]            = "pinned", /* NO_EVICT */
+		[ 22 ]            = "topdown",
+	};
+	const struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
+
+	drm_printf_indent(p, indent, "placement=");
+	drm_print_bits(p, bo->mem.placement, plname, 0, ARRAY_SIZE(plname));
+	drm_printf(p, "\n");
+
+	if (bo->mem.bus.is_iomem) {
+		drm_printf_indent(p, indent, "bus.base=%lx\n",
+				  (unsigned long)bo->mem.bus.base);
+		drm_printf_indent(p, indent, "bus.offset=%lx\n",
+				  (unsigned long)bo->mem.bus.offset);
+	}
+}
+EXPORT_SYMBOL(drm_gem_ttm_print_info);
+
+MODULE_DESCRIPTION("DRM gem ttm helpers");
+MODULE_LICENSE("GPL");

include/drm/drm_gem_ttm_helper.h

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef DRM_GEM_TTM_HELPER_H
+#define DRM_GEM_TTM_HELPER_H
+
+#include <linux/kernel.h>
+
+#include <drm/drm_gem.h>
+#include <drm/drm_device.h>
+#include <drm/ttm/ttm_bo_api.h>
+#include <drm/ttm/ttm_bo_driver.h>
+
+#define drm_gem_ttm_of_gem(gem_obj) \
+	container_of(gem_obj, struct ttm_buffer_object, base)
+
+void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
+			    const struct drm_gem_object *gem);
+
+#endif