drm/i915: Add macro for SSEU stride calculation

Subslice stride and EU stride are calculated multiple times in
i915_query. Move this calculation to a macro to reduce code duplication.

v2: update headers in intel_sseu.h
v3: use GEN_SSEU_STRIDE for stride calculations in intel_sseu.h
    apply s/bits/max_entries/ to GEN_SSEU_STRIDE parameter

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190524154022.13575-3-stuart.summers@intel.com

drivers/gpu/drm/i915/gt/intel_sseu.h

@@ -8,11 +8,13 @@
 #define __INTEL_SSEU_H__
 
 #include <linux/types.h>
+#include <linux/kernel.h>
 
 struct drm_i915_private;
 
 #define GEN_MAX_SLICES		(6) /* CNL upper bound */
 #define GEN_MAX_SUBSLICES	(8) /* ICL upper bound */
+#define GEN_SSEU_STRIDE(max_entries) DIV_ROUND_UP(max_entries, BITS_PER_BYTE)
 
 struct sseu_dev_info {
 	u8 slice_mask;

drivers/gpu/drm/i915/i915_query.c

@@ -37,6 +37,8 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
 	const struct sseu_dev_info *sseu = &RUNTIME_INFO(dev_priv)->sseu;
 	struct drm_i915_query_topology_info topo;
 	u32 slice_length, subslice_length, eu_length, total_length;
+	u8 subslice_stride = GEN_SSEU_STRIDE(sseu->max_subslices);
+	u8 eu_stride = GEN_SSEU_STRIDE(sseu->max_eus_per_subslice);
 	int ret;
 
 	if (query_item->flags != 0)
@@ -48,12 +50,10 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
 	BUILD_BUG_ON(sizeof(u8) != sizeof(sseu->slice_mask));
 
 	slice_length = sizeof(sseu->slice_mask);
-	subslice_length = sseu->max_slices *
-		DIV_ROUND_UP(sseu->max_subslices, BITS_PER_BYTE);
-	eu_length = sseu->max_slices * sseu->max_subslices *
-		DIV_ROUND_UP(sseu->max_eus_per_subslice, BITS_PER_BYTE);
-
-	total_length = sizeof(topo) + slice_length + subslice_length + eu_length;
+	subslice_length = sseu->max_slices * subslice_stride;
+	eu_length = sseu->max_slices * sseu->max_subslices * eu_stride;
+	total_length = sizeof(topo) + slice_length + subslice_length +
+		       eu_length;
 
 	ret = copy_query_item(&topo, sizeof(topo), total_length,
 			      query_item);
@@ -69,10 +69,9 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
 	topo.max_eus_per_subslice = sseu->max_eus_per_subslice;
 
 	topo.subslice_offset = slice_length;
-	topo.subslice_stride = DIV_ROUND_UP(sseu->max_subslices, BITS_PER_BYTE);
+	topo.subslice_stride = subslice_stride;
 	topo.eu_offset = slice_length + subslice_length;
-	topo.eu_stride =
-		DIV_ROUND_UP(sseu->max_eus_per_subslice, BITS_PER_BYTE);
+	topo.eu_stride = eu_stride;
 
 	if (__copy_to_user(u64_to_user_ptr(query_item->data_ptr),
 			   &topo, sizeof(topo)))

drivers/gpu/drm/i915/intel_device_info.h

@@ -231,8 +231,7 @@ static inline unsigned int sseu_subslice_total(const struct sseu_dev_info *sseu)
 static inline int sseu_eu_idx(const struct sseu_dev_info *sseu,
 			      int slice, int subslice)
 {
-	int subslice_stride = DIV_ROUND_UP(sseu->max_eus_per_subslice,
-					   BITS_PER_BYTE);
+	int subslice_stride = GEN_SSEU_STRIDE(sseu->max_eus_per_subslice);
 	int slice_stride = sseu->max_subslices * subslice_stride;
 
 	return slice * slice_stride + subslice * subslice_stride;
@@ -244,8 +243,7 @@ static inline u16 sseu_get_eus(const struct sseu_dev_info *sseu,
 	int i, offset = sseu_eu_idx(sseu, slice, subslice);
 	u16 eu_mask = 0;
 
-	for (i = 0;
-	     i < DIV_ROUND_UP(sseu->max_eus_per_subslice, BITS_PER_BYTE); i++) {
+	for (i = 0; i < GEN_SSEU_STRIDE(sseu->max_eus_per_subslice); i++) {
 		eu_mask |= ((u16) sseu->eu_mask[offset + i]) <<
 			(i * BITS_PER_BYTE);
 	}
@@ -258,8 +256,7 @@ static inline void sseu_set_eus(struct sseu_dev_info *sseu,
 {
 	int i, offset = sseu_eu_idx(sseu, slice, subslice);
 
-	for (i = 0;
-	     i < DIV_ROUND_UP(sseu->max_eus_per_subslice, BITS_PER_BYTE); i++) {
+	for (i = 0; i < GEN_SSEU_STRIDE(sseu->max_eus_per_subslice); i++) {
 		sseu->eu_mask[offset + i] =
 			(eu_mask >> (BITS_PER_BYTE * i)) & 0xff;
 	}