[PATCH i-g-t v2 5/6] lib/intel_mocs: add defer-to-pat-index

[Matthew Auld <matthew.auld@intel.com>]

At least on Xe2 it looks like we can just use MOCS index zero to defer
the selected caching mode to that of the PAT index. This will be useful
in an upcoming patch.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Zbigniew Kempczyński <zbigniew.kempczynski@intel.com>
---
 lib/intel_mocs.c | 14 ++++++++++++++
 lib/intel_mocs.h |  1 +
 2 files changed, 15 insertions(+)

diff --git a/lib/intel_mocs.c b/lib/intel_mocs.c
index 4a9c305dc..bf6ee1958 100644
--- a/lib/intel_mocs.c
+++ b/lib/intel_mocs.c
@@ -9,6 +9,7 @@
 struct drm_intel_mocs_index {
 	uint8_t uc_index;
 	uint8_t wb_index;
+	uint8_t deferred_index;
 };
 
 static void get_mocs_index(int fd, struct drm_intel_mocs_index *mocs)
@@ -25,6 +26,7 @@ static void get_mocs_index(int fd, struct drm_intel_mocs_index *mocs)
 	if (intel_graphics_ver(devid) >= IP_VER(20, 0)) {
 		mocs->uc_index = 3;
 		mocs->wb_index = 4;
+		mocs->deferred_index = 0;
 	} else if (IS_METEORLAKE(devid)) {
 		mocs->uc_index = 5;
 		mocs->wb_index = 10;
@@ -60,3 +62,15 @@ uint8_t intel_get_uc_mocs_index(int fd)
 
 	return mocs.uc_index;
 }
+
+uint8_t intel_get_deferred_mocs_index(int fd)
+{
+	struct drm_intel_mocs_index mocs;
+	uint16_t dev_id = intel_get_drm_devid(fd);
+
+	igt_assert(AT_LEAST_GEN(dev_id, 20));
+
+	get_mocs_index(fd, &mocs);
+
+	return mocs.deferred_index;
+}
diff --git a/lib/intel_mocs.h b/lib/intel_mocs.h
index b5c79b0e1..bfdc23210 100644
--- a/lib/intel_mocs.h
+++ b/lib/intel_mocs.h
@@ -12,5 +12,6 @@
 
 uint8_t intel_get_wb_mocs_index(int fd);
 uint8_t intel_get_uc_mocs_index(int fd);
+uint8_t intel_get_deferred_mocs_index(int fd);
 
 #endif /* _INTEL_MOCS_H */
-- 
2.43.2