1 files changed, 140 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_batch_pool.c b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
new file mode 100644
index 000000000..f3890b664
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
@@ -0,0 +1,140 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2014-2018 Intel Corporation
+ */
+
+#include "i915_gem_batch_pool.h"
+#include "i915_drv.h"
+
+/**
+ * DOC: batch pool
+ *
+ * In order to submit batch buffers as 'secure', the software command parser
+ * must ensure that a batch buffer cannot be modified after parsing. It does
+ * this by copying the user provided batch buffer contents to a kernel owned
+ * buffer from which the hardware will actually execute, and by carefully
+ * managing the address space bindings for such buffers.
+ *
+ * The batch pool framework provides a mechanism for the driver to manage a
+ * set of scratch buffers to use for this purpose. The framework can be
+ * extended to support other uses cases should they arise.
+ */
+
+/**
+ * i915_gem_batch_pool_init() - initialize a batch buffer pool
+ * @pool: the batch buffer pool
+ * @engine: the associated request submission engine
+ */
+void i915_gem_batch_pool_init(struct i915_gem_batch_pool *pool,
+			      struct intel_engine_cs *engine)
+{
+	int n;
+
+	pool->engine = engine;
+
+	for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
+		INIT_LIST_HEAD(&pool->cache_list[n]);
+}
+
+/**
+ * i915_gem_batch_pool_fini() - clean up a batch buffer pool
+ * @pool: the pool to clean up
+ *
+ * Note: Callers must hold the struct_mutex.
+ */
+void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool)
+{
+	int n;
+
+	lockdep_assert_held(&pool->engine->i915->drm.struct_mutex);
+
+	for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) {
+		struct drm_i915_gem_object *obj, *next;
+
+		list_for_each_entry_safe(obj, next,
+					 &pool->cache_list[n],
+					 batch_pool_link)
+			__i915_gem_object_release_unless_active(obj);
+
+		INIT_LIST_HEAD(&pool->cache_list[n]);
+	}
+}
+
+/**
+ * i915_gem_batch_pool_get() - allocate a buffer from the pool
+ * @pool: the batch buffer pool
+ * @size: the minimum desired size of the returned buffer
+ *
+ * Returns an inactive buffer from @pool with at least @size bytes,
+ * with the pages pinned. The caller must i915_gem_object_unpin_pages()
+ * on the returned object.
+ *
+ * Note: Callers must hold the struct_mutex
+ *
+ * Return: the buffer object or an error pointer
+ */
+struct drm_i915_gem_object *
+i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
+			size_t size)
+{
+	struct drm_i915_gem_object *obj;
+	struct list_head *list;
+	int n, ret;
+
+	lockdep_assert_held(&pool->engine->i915->drm.struct_mutex);
+
+	/* Compute a power-of-two bucket, but throw everything greater than
+	 * 16KiB into the same bucket: i.e. the the buckets hold objects of
+	 * (1 page, 2 pages, 4 pages, 8+ pages).
+	 */
+	n = fls(size >> PAGE_SHIFT) - 1;
+	if (n >= ARRAY_SIZE(pool->cache_list))
+		n = ARRAY_SIZE(pool->cache_list) - 1;
+	list = &pool->cache_list[n];
+
+	list_for_each_entry(obj, list, batch_pool_link) {
+		/* The batches are strictly LRU ordered */
+		if (i915_gem_object_is_active(obj)) {
+			struct reservation_object *resv = obj->resv;
+
+			if (!reservation_object_test_signaled_rcu(resv, true))
+				break;
+
+			i915_retire_requests(pool->engine->i915);
+			GEM_BUG_ON(i915_gem_object_is_active(obj));
+
+			/*
+			 * The object is now idle, clear the array of shared
+			 * fences before we add a new request. Although, we
+			 * remain on the same engine, we may be on a different
+			 * timeline and so may continually grow the array,
+			 * trapping a reference to all the old fences, rather
+			 * than replace the existing fence.
+			 */
+			if (rcu_access_pointer(resv->fence)) {
+				reservation_object_lock(resv, NULL);
+				reservation_object_add_excl_fence(resv, NULL);
+				reservation_object_unlock(resv);
+			}
+		}
+
+		GEM_BUG_ON(!reservation_object_test_signaled_rcu(obj->resv,
+								 true));
+
+		if (obj->base.size >= size)
+			goto found;
+	}
+
+	obj = i915_gem_object_create_internal(pool->engine->i915, size);
+	if (IS_ERR(obj))
+		return obj;
+
+found:
+	ret = i915_gem_object_pin_pages(obj);
+	if (ret)
+		return ERR_PTR(ret);
+
+	list_move_tail(&obj->batch_pool_link, list);
+	return obj;
+}