[PATCH v34 2/6] drm/xe/xe_pagefault: Pack engine class instance into u8

[Jonathan Cavitt <jonathan.cavitt@intel.com>]

Pack the engine class and instance fields into a single u8 to save space
in struct xe_pagefault.  The saved space will be used later to store
something else.

Suggested-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
---
 drivers/gpu/drm/xe/xe_guc_pagefault.c   |  7 +++++--
 drivers/gpu/drm/xe/xe_pagefault.c       | 11 +++++++----
 drivers/gpu/drm/xe/xe_pagefault_types.h | 16 ++++++++++++----
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_guc_pagefault.c b/drivers/gpu/drm/xe/xe_guc_pagefault.c
index d48f6ed103bb..8eaa1dfc1e66 100644
--- a/drivers/gpu/drm/xe/xe_guc_pagefault.c
+++ b/drivers/gpu/drm/xe/xe_guc_pagefault.c
@@ -85,8 +85,11 @@ int xe_guc_pagefault_handler(struct xe_guc *guc, u32 *msg, u32 len)
 				   FIELD_GET(PFD_FAULT_LEVEL, msg[0])) |
 			FIELD_PREP(XE_PAGEFAULT_TYPE_MASK,
 				   FIELD_GET(PFD_FAULT_TYPE, msg[2]));
-	pf.consumer.engine_class = FIELD_GET(PFD_ENG_CLASS, msg[0]);
-	pf.consumer.engine_instance = FIELD_GET(PFD_ENG_INSTANCE, msg[0]);
+	pf.consumer.engine_class_instance =
+		FIELD_PREP(XE_PAGEFAULT_ENGINE_CLASS_MASK,
+			   FIELD_GET(PFD_ENG_CLASS, msg[0])) |
+		FIELD_PREP(XE_PAGEFAULT_ENGINE_INSTANCE_MASK,
+			   FIELD_GET(PFD_ENG_INSTANCE, msg[0]));
 
 	pf.producer.private = guc;
 	pf.producer.ops = &guc_pagefault_ops;
diff --git a/drivers/gpu/drm/xe/xe_pagefault.c b/drivers/gpu/drm/xe/xe_pagefault.c
index 0281b5b6d4ab..47b6a7628dc1 100644
--- a/drivers/gpu/drm/xe/xe_pagefault.c
+++ b/drivers/gpu/drm/xe/xe_pagefault.c
@@ -229,13 +229,15 @@ static bool xe_pagefault_queue_pop(struct xe_pagefault_queue *pf_queue,
 
 static void xe_pagefault_print(struct xe_pagefault *pf)
 {
+	enum xe_engine_class class = FIELD_GET(XE_PAGEFAULT_ENGINE_CLASS_MASK,
+					       pf->consumer.engine_class_instance);
 	xe_gt_info(pf->gt, "\n\tASID: %d\n"
 		   "\tFaulted Address: 0x%08x%08x\n"
 		   "\tFaultType: %lu\n"
 		   "\tAccessType: %d\n"
 		   "\tFaultLevel: %lu\n"
 		   "\tEngineClass: %d %s\n"
-		   "\tEngineInstance: %d\n",
+		   "\tEngineInstance: %lu\n",
 		   pf->consumer.asid,
 		   upper_32_bits(pf->consumer.page_addr),
 		   lower_32_bits(pf->consumer.page_addr),
@@ -244,9 +246,10 @@ static void xe_pagefault_print(struct xe_pagefault *pf)
 		   pf->consumer.access_type,
 		   FIELD_GET(XE_PAGEFAULT_LEVEL_MASK,
 			     pf->consumer.fault_type_level),
-		   pf->consumer.engine_class,
-		   xe_hw_engine_class_to_str(pf->consumer.engine_class),
-		   pf->consumer.engine_instance);
+		   class,
+		   xe_hw_engine_class_to_str(class),
+		   FIELD_GET(XE_PAGEFAULT_ENGINE_INSTANCE_MASK,
+			     pf->consumer.engine_class_instance));
 }
 
 static void xe_pagefault_queue_work(struct work_struct *w)
diff --git a/drivers/gpu/drm/xe/xe_pagefault_types.h b/drivers/gpu/drm/xe/xe_pagefault_types.h
index 0e378f41ede6..a14725a02f39 100644
--- a/drivers/gpu/drm/xe/xe_pagefault_types.h
+++ b/drivers/gpu/drm/xe/xe_pagefault_types.h
@@ -80,10 +80,18 @@ struct xe_pagefault {
 #define XE_PAGEFAULT_TYPE_LEVEL_NACK		0xff	/* Producer indicates nack fault */
 #define XE_PAGEFAULT_LEVEL_MASK			GENMASK(3, 0)
 #define XE_PAGEFAULT_TYPE_MASK			GENMASK(7, 4)
-		/** @consumer.engine_class: engine class */
-		u8 engine_class;
-		/** @consumer.engine_instance: engine instance */
-		u8 engine_instance;
+		/**
+		 * @consumer.engine_class_instance: engine class and instance, packed
+		 * into a single u8 to keep compact
+		 */
+		u8 engine_class_instance;
+#define XE_PAGEFAULT_ENGINE_CLASS_MASK		GENMASK(3, 0)
+#define XE_PAGEFAULT_ENGINE_INSTANCE_MASK	GENMASK(7, 4)
+		/**
+		 * consumer.align: buffer u8 to keep struct aligned to u64.
+		 * Will be used later to store data.
+		 */
+		u8 align;
 		/** consumer.reserved: reserved bits for future expansion */
 		u64 reserved;
 	} consumer;
-- 
2.43.0