drm/nouveau/core/memory: comptag allocation

nvkm_memory is going to be used by the upcoming mmu rework for the basic
representation of a memory allocation, as such, this commit adds support
for comptag allocation to nvkm_memory.

This is very simple for now, in that it requires comptags for the entire
memory allocation even if only certain ranges are compressed.

Support for tracking ranges will be added at a later date.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nvkm/core/memory.c b/drivers/gpu/drm/nouveau/nvkm/core/memory.c
index 8903c04c977e..13cfcdde99fd 100644
--- a/drivers/gpu/drm/nouveau/nvkm/core/memory.c
+++ b/drivers/gpu/drm/nouveau/nvkm/core/memory.c
@@ -22,9 +22,80 @@
  * Authors: Ben Skeggs <bskeggs@redhat.com>
  */
 #include <core/memory.h>
+#include <core/mm.h>
+#include <subdev/fb.h>
 #include <subdev/instmem.h>
 
 void
+nvkm_memory_tags_put(struct nvkm_memory *memory, struct nvkm_device *device,
+		     struct nvkm_tags **ptags)
+{
+	struct nvkm_fb *fb = device->fb;
+	struct nvkm_tags *tags = *ptags;
+	if (tags) {
+		mutex_lock(&fb->subdev.mutex);
+		if (refcount_dec_and_test(&tags->refcount)) {
+			nvkm_mm_free(&fb->tags, &tags->mn);
+			kfree(memory->tags);
+			memory->tags = NULL;
+		}
+		mutex_unlock(&fb->subdev.mutex);
+		*ptags = NULL;
+	}
+}
+
+int
+nvkm_memory_tags_get(struct nvkm_memory *memory, struct nvkm_device *device,
+		     u32 nr, void (*clr)(struct nvkm_device *, u32, u32),
+		     struct nvkm_tags **ptags)
+{
+	struct nvkm_fb *fb = device->fb;
+	struct nvkm_tags *tags;
+
+	mutex_lock(&fb->subdev.mutex);
+	if ((tags = memory->tags)) {
+		/* If comptags exist for the memory, but a different amount
+		 * than requested, the buffer is being mapped with settings
+		 * that are incompatible with existing mappings.
+		 */
+		if (tags->mn && tags->mn->length != nr) {
+			mutex_unlock(&fb->subdev.mutex);
+			return -EINVAL;
+		}
+
+		refcount_inc(&tags->refcount);
+		*ptags = tags;
+		return 0;
+	}
+
+	if (!(tags = kmalloc(sizeof(*tags), GFP_KERNEL))) {
+		mutex_unlock(&fb->subdev.mutex);
+		return -ENOMEM;
+	}
+
+	if (!nvkm_mm_head(&fb->tags, 0, 1, nr, nr, 1, &tags->mn)) {
+		if (clr)
+			clr(device, tags->mn->offset, tags->mn->length);
+	} else {
+		/* Failure to allocate HW comptags is not an error, the
+		 * caller should fall back to an uncompressed map.
+		 *
+		 * As memory can be mapped in multiple places, we still
+		 * need to track the allocation failure and ensure that
+		 * any additional mappings remain uncompressed.
+		 *
+		 * This is handled by returning an empty nvkm_tags.
+		 */
+		tags->mn = NULL;
+	}
+
+	refcount_set(&tags->refcount, 1);
+	mutex_unlock(&fb->subdev.mutex);
+	*ptags = tags;
+	return 0;
+}
+
+void
 nvkm_memory_ctor(const struct nvkm_memory_func *func,
 		 struct nvkm_memory *memory)
 {