drm/i915/ttm: add ttm_buddy_man

Add back our standalone i915_buddy allocator and integrate it into a
ttm_resource_manager. This will plug into our ttm backend for managing
device local-memory in the next couple of patches.

v2(Thomas):
    - Return -ENOSPC from the buddy; ttm expects this in order to
      trigger eviction
    - Drop the unnecessary inline
    - bo->page_alignment is in page units

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Acked-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210616152501.394518-1-matthew.auld@intel.com

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
new file mode 100644
index 000000000000..26026213e20a
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#ifndef __I915_TTM_BUDDY_MANAGER_H__
+#define __I915_TTM_BUDDY_MANAGER_H__
+
+#include <linux/list.h>
+#include <linux/types.h>
+
+#include <drm/ttm/ttm_resource.h>
+
+struct ttm_device;
+struct ttm_resource_manager;
+struct i915_buddy_mm;
+
+/**
+ * struct i915_ttm_buddy_resource
+ *
+ * @base: struct ttm_resource base class we extend
+ * @blocks: the list of struct i915_buddy_block for this resource/allocation
+ * @mm: the struct i915_buddy_mm for this resource
+ *
+ * Extends the struct ttm_resource to manage an address space allocation with
+ * one or more struct i915_buddy_block.
+ */
+struct i915_ttm_buddy_resource {
+	struct ttm_resource base;
+	struct list_head blocks;
+	struct i915_buddy_mm *mm;
+};
+
+/**
+ * to_ttm_buddy_resource
+ *
+ * @res: the resource to upcast
+ *
+ * Upcast the struct ttm_resource object into a struct i915_ttm_buddy_resource.
+ */
+static inline struct i915_ttm_buddy_resource *
+to_ttm_buddy_resource(struct ttm_resource *res)
+{
+	return container_of(res, struct i915_ttm_buddy_resource, base);
+}
+
+int i915_ttm_buddy_man_init(struct ttm_device *bdev,
+			    unsigned type, bool use_tt,
+			    u64 size, u64 chunk_size);
+int i915_ttm_buddy_man_fini(struct ttm_device *bdev,
+			    unsigned int type);
+
+int i915_ttm_buddy_man_reserve(struct ttm_resource_manager *man,
+			       u64 start, u64 size);
+
+#endif