[igt-dev] [PATCH v2] lib/i915: gem_engine_topology: get eb flags from engine's class:instance

[Andi Shyti]

The execution buffer flag value has now the engine index as it is
mapped in the context. Retrieve the mapped index by interrogating
the driver starting from the class/instance tuple.

A "gem_context_get_eb_flags_ci" helper allows to avoid declaring
a "struct i915_engine_class_instance" for the purpose.

Return -EINVAL if the engine is not mapped in the given context.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Signed-off-by: Andi Shyti <andi.shyti at intel.com>
Cc: Ramalingam C <ramalingam.c at intel.com>
---
V1 --> V2 changelog:
--------------------
- refactor the code to avoid initializing the context just for
  the purpose of getting the execution buffer flag (thanks
  Tvrtko)

 lib/i915/gem_engine_topology.c | 31 +++++++++++++++++++++++++++++++
 lib/i915/gem_engine_topology.h |  6 ++++++
 2 files changed, 37 insertions(+)

diff --git a/lib/i915/gem_engine_topology.c b/lib/i915/gem_engine_topology.c
index fdd1b951672b..fd5be3491b89 100644
--- a/lib/i915/gem_engine_topology.c
+++ b/lib/i915/gem_engine_topology.c
@@ -270,6 +270,37 @@ int gem_context_lookup_engine(int fd, uint64_t engine, uint32_t ctx_id,
 	return 0;
 }
 
+int gem_context_get_eb_flags(int fd, uint32_t ctx_id,
+			     struct i915_engine_class_instance *ci)
+{
+	DEFINE_CONTEXT_ENGINES_PARAM(engines, param, ctx_id, GEM_MAX_ENGINES);
+
+	/* legacy kernels */
+	if (gem_topology_get_param(fd, &param)) {
+		const struct intel_execution_engine2 *e;
+
+		__for_each_static_engine(e)
+			if (e->class == ci->engine_class &&
+			    e->instance == ci->engine_instance)
+				return e->flags;
+
+		return -EINVAL;
+	}
+
+	/* context has no engine mapped */
+	if (!param.size)
+		return -EINVAL;
+
+	/* engine map lookup */
+	for (int i = 0; i < param.size; i++)
+		if (engines.engines[i].engine_class == ci->engine_class &&
+		    engines.engines[i].engine_instance == ci->engine_instance)
+			return i;
+
+	/* engine is not mapped in the given context */
+	return -EINVAL;
+}
+
 void gem_context_set_all_engines(int fd, uint32_t ctx)
 {
 	DEFINE_CONTEXT_ENGINES_PARAM(engines, param, ctx, GEM_MAX_ENGINES);
diff --git a/lib/i915/gem_engine_topology.h b/lib/i915/gem_engine_topology.h
index 2415fd1e379b..57b5473bbd5a 100644
--- a/lib/i915/gem_engine_topology.h
+++ b/lib/i915/gem_engine_topology.h
@@ -53,6 +53,12 @@ int gem_context_lookup_engine(int fd, uint64_t engine, uint32_t ctx_id,
 
 void gem_context_set_all_engines(int fd, uint32_t ctx);
 
+int gem_context_get_eb_flags(int fd, uint32_t ctx_id,
+			     struct i915_engine_class_instance *ci);
+
+#define gem_context_get_eb_flags_ci(f, c, ...) \
+	gem_context_get_eb_flags(f, c, &((struct i915_engine_class_instance){__VA_ARGS__}))
+
 #define __for_each_static_engine(e__) \
 	for ((e__) = intel_execution_engines2; (e__)->name; (e__)++)
 
-- 
2.20.1