drm: debugfs: provide infrastructure to dump a DRM GPU VA space

This commit adds a function to dump a DRM GPU VA space and a macro for
drivers to register the struct drm_info_list 'gpuvas' entry.

Most likely, most drivers might maintain one DRM GPU VA space per struct
drm_file, but there might also be drivers not having a fixed relation
between DRM GPU VA spaces and a DRM core infrastructure, hence we need the
indirection via the driver iterating it's maintained DRM GPU VA spaces.

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230720001443.2380-3-dakr@redhat.com

drivers/gpu/drm/drm_debugfs.c

@@ -39,6 +39,7 @@
 #include <drm/drm_file.h>
 #include <drm/drm_gem.h>
 #include <drm/drm_managed.h>
+#include <drm/drm_gpuva_mgr.h>
 
 #include "drm_crtc_internal.h"
 #include "drm_internal.h"
@@ -175,6 +176,45 @@ static const struct file_operations drm_debugfs_fops = {
 	.release = single_release,
 };
 
+/**
+ * drm_debugfs_gpuva_info - dump the given DRM GPU VA space
+ * @m: pointer to the &seq_file to write
+ * @mgr: the &drm_gpuva_manager representing the GPU VA space
+ *
+ * Dumps the GPU VA mappings of a given DRM GPU VA manager.
+ *
+ * For each DRM GPU VA space drivers should call this function from their
+ * &drm_info_list's show callback.
+ *
+ * Returns: 0 on success, -ENODEV if the &mgr is not initialized
+ */
+int drm_debugfs_gpuva_info(struct seq_file *m,
+			   struct drm_gpuva_manager *mgr)
+{
+	struct drm_gpuva *va, *kva = &mgr->kernel_alloc_node;
+
+	if (!mgr->name)
+		return -ENODEV;
+
+	seq_printf(m, "DRM GPU VA space (%s) [0x%016llx;0x%016llx]\n",
+		   mgr->name, mgr->mm_start, mgr->mm_start + mgr->mm_range);
+	seq_printf(m, "Kernel reserved node [0x%016llx;0x%016llx]\n",
+		   kva->va.addr, kva->va.addr + kva->va.range);
+	seq_puts(m, "\n");
+	seq_puts(m, " VAs | start              | range              | end                | object             | object offset\n");
+	seq_puts(m, "-------------------------------------------------------------------------------------------------------------\n");
+	drm_gpuva_for_each_va(va, mgr) {
+		if (unlikely(va == kva))
+			continue;
+
+		seq_printf(m, "     | 0x%016llx | 0x%016llx | 0x%016llx | 0x%016llx | 0x%016llx\n",
+			   va->va.addr, va->va.range, va->va.addr + va->va.range,
+			   (u64)va->gem.obj, va->gem.offset);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_debugfs_gpuva_info);
 
 /**
  * drm_debugfs_create_files - Initialize a given set of debugfs files for DRM

include/drm/drm_debugfs.h

@@ -34,6 +34,22 @@
 
 #include <linux/types.h>
 #include <linux/seq_file.h>
+
+#include <drm/drm_gpuva_mgr.h>
+
+/**
+ * DRM_DEBUGFS_GPUVA_INFO - &drm_info_list entry to dump a GPU VA space
+ * @show: the &drm_info_list's show callback
+ * @data: driver private data
+ *
+ * Drivers should use this macro to define a &drm_info_list entry to provide a
+ * debugfs file for dumping the GPU VA space regions and mappings.
+ *
+ * For each DRM GPU VA space drivers should call drm_debugfs_gpuva_info() from
+ * their @show callback.
+ */
+#define DRM_DEBUGFS_GPUVA_INFO(show, data) {"gpuvas", show, DRIVER_GEM_GPUVA, data}
+
 /**
  * struct drm_info_list - debugfs info list entry
  *
@@ -134,6 +150,9 @@ void drm_debugfs_add_file(struct drm_device *dev, const char *name,
 
 void drm_debugfs_add_files(struct drm_device *dev,
 			   const struct drm_debugfs_info *files, int count);
+
+int drm_debugfs_gpuva_info(struct seq_file *m,
+			   struct drm_gpuva_manager *mgr);
 #else
 static inline void drm_debugfs_create_files(const struct drm_info_list *files,
 					    int count, struct dentry *root,
@@ -155,6 +174,12 @@ static inline void drm_debugfs_add_files(struct drm_device *dev,
 					 const struct drm_debugfs_info *files,
 					 int count)
 {}
+
+static inline int drm_debugfs_gpuva_info(struct seq_file *m,
+					 struct drm_gpuva_manager *mgr)
+{
+	return 0;
+}
 #endif
 
 #endif /* _DRM_DEBUGFS_H_ */