[igt-dev] [PATCH i-g-t 13/93] lib/i915/gem_engine_topology: Add an iterator for intel_ctx_t (v3)

[Jason Ekstrand]

v2 (Daniel Vetter):
 - Add documentation

v3 (Zbigniew Kempczyński):
 - Fix a typo in the docs
 - Add an igt_assert(ctx) in intel_engine_list_for_ctx_cfg()

Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 lib/i915/gem_engine_topology.c | 70 ++++++++++++++++++++++++++++++++++
 lib/i915/gem_engine_topology.h | 29 +++++++++++++-
 2 files changed, 97 insertions(+), 2 deletions(-)

diff --git a/lib/i915/gem_engine_topology.c b/lib/i915/gem_engine_topology.c
index 6bceb909..50f4bde7 100644
--- a/lib/i915/gem_engine_topology.c
+++ b/lib/i915/gem_engine_topology.c
@@ -39,6 +39,47 @@
  *
  * This helper library contains functions used for querying and dealing
  * with engines in GEM contexts.
+ *
+ * Combined with intel_ctx_t, these helpers give a pretty standard pattern
+ * for testing every engine in a device:
+ * |[<!-- language="C" -->
+ *	const struct intel_execution_engine2 *e;
+ *	const intel_ctx_t *ctx = intel_ctx_create_all_physical(fd);
+ *
+ *	igt_subtest_with_dynamic("basic") {
+ *		for_each_ctx_engine(fd, ctx, e) {
+ *			igt_dynamic_f("%s", e->name)
+ *			run_ctx_test(fd, ctx, e);
+ *		}
+ *	}
+ * ]|
+ * This pattern works regardless of whether or not the engines topology API
+ * is available and regardless of whether or not your platform supports
+ * contexts.  If engines are unavailable, it falls back to a legacy context
+ * and if contexts are unavailable, intel_ctx_create_all_physical() will
+ * return a wrapper around ctx0.
+ *
+ * If, for some reason, you want to create a second identical context to
+ * use with your engine iterator, duplicating the context is easy:
+ * |[<!-- language="C" -->
+ *	const intel_ctx_t *ctx2 = intel_ctx_create(fd, &ctx->cfg);
+ * ]|
+ *
+ * If you want each subtest to always create its own contexts, there are
+ * also iterators which work only on a context config.  As long as all
+ * contexts are created from that config, or from one with an identical set
+ * of engines, the iterator will be valid for those contexts.
+ * |[<!-- language="C" -->
+ *	const struct intel_execution_engine2 *e;
+ *	intel_ctx_cfg_t cfg = intel_ctx_cfg_all_physical(fd);
+ *
+ *	igt_subtest_with_dynamic("basic") {
+ *		for_each_ctx_cfg_engine(fd, &cfg, e) {
+ *			igt_dynamic_f("%s", e->name)
+ *			run_ctx_cfg_test(fd, &cfg, e);
+ *		}
+ *	}
+ * ]|
  */
 
 /*
@@ -256,6 +297,35 @@ struct intel_engine_data intel_engine_list_of_physical(int fd)
 	return intel_engine_list_for_static(fd);
 }
 
+/**
+ * intel_engine_list_for_ctx_cfg:
+ * @fd: open i915 drm file descriptor
+ * @cfg: Context config
+ *
+ * Returns the list of all engines in the context config
+ */
+struct intel_engine_data
+intel_engine_list_for_ctx_cfg(int fd, const intel_ctx_cfg_t *cfg)
+{
+	igt_assert(cfg);
+	if (fd >= 0 && cfg->num_engines) {
+		struct intel_engine_data engine_data = { };
+		int i;
+
+		engine_data.nengines = cfg->num_engines;
+		for (i = 0; i < cfg->num_engines; i++)
+			init_engine(&engine_data.engines[i],
+				    cfg->engines[i].engine_class,
+				    cfg->engines[i].engine_instance,
+				    i);
+
+		return engine_data;
+	} else {
+		/* This is a legacy context */
+		return intel_engine_list_for_static(fd);
+	}
+}
+
 static int gem_topology_get_param(int fd,
 				  struct drm_i915_gem_context_param *p)
 {
diff --git a/lib/i915/gem_engine_topology.h b/lib/i915/gem_engine_topology.h
index bd93e410..92d9a479 100644
--- a/lib/i915/gem_engine_topology.h
+++ b/lib/i915/gem_engine_topology.h
@@ -26,8 +26,7 @@
 
 #include "igt_gt.h"
 #include "i915_drm.h"
-
-#define GEM_MAX_ENGINES		I915_EXEC_RING_MASK + 1
+#include "intel_ctx.h"
 
 int __gem_query_engines(int fd,
 			struct drm_i915_query_engine_info *query_engines,
@@ -51,6 +50,7 @@ struct intel_engine_data {
 
 bool gem_has_engine_topology(int fd);
 struct intel_engine_data intel_engine_list_of_physical(int fd);
+struct intel_engine_data intel_engine_list_for_ctx_cfg(int fd, const intel_ctx_cfg_t *cfg);
 struct intel_engine_data intel_init_engine_list(int fd, uint32_t ctx_id);
 
 /* iteration functions */
@@ -81,6 +81,31 @@ struct intel_execution_engine2 gem_eb_flags_to_engine(unsigned int flags);
 #define __for_each_static_engine(e__) \
 	for ((e__) = intel_execution_engines2; (e__)->name[0]; (e__)++)
 
+/**
+ * for_each_ctx_cfg_engine
+ * @fd__: open i915 drm file descriptor
+ * @ctx_cfg__: Intel context config
+ * @e__: struct intel_execution_engine2 iterator
+ *
+ * Iterates over each physical engine in the context config
+ */
+#define for_each_ctx_cfg_engine(fd__, ctx_cfg__, e__) \
+	for (struct intel_engine_data i__##e__ = \
+			intel_engine_list_for_ctx_cfg(fd__, ctx_cfg__); \
+	     ((e__) = intel_get_current_engine(&i__##e__)); \
+	     intel_next_engine(&i__##e__))
+
+/**
+ * for_each_ctx_engine
+ * @fd__: open i915 drm file descriptor
+ * @ctx__: Intel context wrapper
+ * @e__: struct intel_execution_engine2 iterator
+ *
+ * Iterates over each physical engine in the context
+ */
+#define for_each_ctx_engine(fd__, ctx__, e__) \
+	for_each_ctx_cfg_engine(fd__, &(ctx__)->cfg, e__)
+
 #define for_each_context_engine(fd__, ctx__, e__) \
 	for (struct intel_engine_data i__ = intel_init_engine_list(fd__, ctx__); \
 	     ((e__) = intel_get_current_engine(&i__)); \
-- 
2.31.1