+struct cmd_node {
+ const struct drm_i915_cmd_descriptor *desc;
+ struct hlist_node node;
+};
+
+/*
+ * Different command ranges have different numbers of bits for the opcode. For
+ * example, MI commands use bits 31:23 while 3D commands use bits 31:16. The
+ * problem is that, for example, MI commands use bits 22:16 for other fields
+ * such as GGTT vs PPGTT bits. If we include those bits in the mask then when
+ * we mask a command from a batch it could hash to the wrong bucket due to
+ * non-opcode bits being set. But if we don't include those bits, some 3D
+ * commands may hash to the same bucket due to not including opcode bits that
+ * make the command unique. For now, we will risk hashing to the same bucket.
+ *
+ * If we attempt to generate a perfect hash, we should be able to look at bits
+ * 31:29 of a command from a batch buffer and use the full mask for that
+ * client. The existing INSTR_CLIENT_MASK/SHIFT defines can be used for this.
+ */
+#define CMD_HASH_MASK STD_MI_OPCODE_MASK
+
+static int init_hash_table(struct intel_engine_cs *ring,
+ const struct drm_i915_cmd_table *cmd_tables,
+ int cmd_table_count)
+{
+ int i, j;
+
+ hash_init(ring->cmd_hash);
+
+ for (i = 0; i < cmd_table_count; i++) {
+ const struct drm_i915_cmd_table *table = &cmd_tables[i];
+
+ for (j = 0; j < table->count; j++) {
+ const struct drm_i915_cmd_descriptor *desc =
+ &table->table[j];
+ struct cmd_node *desc_node =
+ kmalloc(sizeof(*desc_node), GFP_KERNEL);
+
+ if (!desc_node)
+ return -ENOMEM;
+
+ desc_node->desc = desc;
+ hash_add(ring->cmd_hash, &desc_node->node,
+ desc->cmd.value & CMD_HASH_MASK);
+ }
+ }
+
+ return 0;
+}
+
+static void fini_hash_table(struct intel_engine_cs *ring)
+{
+ struct hlist_node *tmp;
+ struct cmd_node *desc_node;
+ int i;
+
+ hash_for_each_safe(ring->cmd_hash, i, tmp, desc_node, node) {
+ hash_del(&desc_node->node);
+ kfree(desc_node);
+ }
+}
+