drm/panfrost: Add BO labelling to Panfrost

Functions for labelling UM-exposed an internal BOs are provided. An
example of the latter would be the Perfcnt sample buffer.

This commit is done in preparation of a following one that will allow
UM to set BO labels through a new ioctl().

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250520174634.353267-2-adrian.larumbe@collabora.com

1 files changed, 42 insertions, 0 deletions

diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 963f04ba2de6..4c5be7ccc9cc 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright 2019 Linaro, Ltd, Rob Herring <robh@kernel.org> */
 
+#include <linux/cleanup.h>
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/dma-buf.h>
@@ -35,6 +36,9 @@ static void panfrost_gem_free_object(struct drm_gem_object *obj)
 	 */
 	WARN_ON_ONCE(!list_empty(&bo->mappings.list));
 
+	kfree_const(bo->label.str);
+	mutex_destroy(&bo->label.lock);
+
 	if (bo->sgts) {
 		int i;
 		int n_sgt = bo->base.base.size / SZ_2M;
@@ -260,6 +264,7 @@ struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t
 	mutex_init(&obj->mappings.lock);
 	obj->base.base.funcs = &panfrost_gem_funcs;
 	obj->base.map_wc = !pfdev->coherent;
+	mutex_init(&obj->label.lock);
 
 	return &obj->base.base;
 }
@@ -302,3 +307,40 @@ panfrost_gem_prime_import_sg_table(struct drm_device *dev,
 
 	return obj;
 }
+
+void
+panfrost_gem_set_label(struct drm_gem_object *obj, const char *label)
+{
+	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+	const char *old_label;
+
+	scoped_guard(mutex, &bo->label.lock) {
+		old_label = bo->label.str;
+		bo->label.str = label;
+	}
+
+	kfree_const(old_label);
+}
+
+void
+panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char *label)
+{
+	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+	const char *str;
+
+	/* We should never attempt labelling a UM-exposed GEM object */
+	if (drm_WARN_ON(bo->base.base.dev, bo->base.base.handle_count > 0))
+		return;
+
+	if (!label)
+		return;
+
+	str = kstrdup_const(label, GFP_KERNEL);
+	if (!str) {
+		/* Failing to allocate memory for a label isn't a fatal condition */
+		drm_warn(bo->base.base.dev, "Not enough memory to allocate BO label");
+		return;
+	}
+
+	panfrost_gem_set_label(obj, str);
+}