drm/i915: Add EU stride runtime parameter

Add a new SSEU runtime parameter, eu_stride, which is
used to mirror the userspace concept of a range of EUs
per subslice.

This patch simply adds the parameter and updates usage
in the QUERY_TOPOLOGY_INFO handler.

v2: Add GEM_BUG_ON to make sure eu_stride is valid
Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190823160307.180813-5-stuart.summers@intel.com

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

@@ -17,6 +17,8 @@ void intel_sseu_set_info(struct sseu_dev_info *sseu, u8 max_slices,
 
 	sseu->ss_stride = GEN_SSEU_STRIDE(sseu->max_subslices);
 	GEM_BUG_ON(sseu->ss_stride > GEN_MAX_SUBSLICE_STRIDE);
+	sseu->eu_stride = GEN_SSEU_STRIDE(sseu->max_eus_per_subslice);
+	GEM_BUG_ON(sseu->eu_stride > GEN_MAX_EU_STRIDE);
 }
 
 unsigned int

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

@@ -16,6 +16,8 @@ struct drm_i915_private;
 #define GEN_MAX_SUBSLICES	(8) /* ICL upper bound */
 #define GEN_SSEU_STRIDE(max_entries) DIV_ROUND_UP(max_entries, BITS_PER_BYTE)
 #define GEN_MAX_SUBSLICE_STRIDE GEN_SSEU_STRIDE(GEN_MAX_SUBSLICES)
+#define GEN_MAX_EUS		(10) /* HSW upper bound */
+#define GEN_MAX_EU_STRIDE GEN_SSEU_STRIDE(GEN_MAX_EUS)
 
 struct sseu_dev_info {
 	u8 slice_mask;
@@ -35,6 +37,7 @@ struct sseu_dev_info {
 	u8 max_eus_per_subslice;
 
 	u8 ss_stride;
+	u8 eu_stride;
 
 	/* We don't have more than 8 eus per subslice at the moment and as we
 	 * store eus enabled using bits, no need to multiply by eus per

drivers/gpu/drm/i915/i915_query.c

@@ -37,7 +37,6 @@ 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 eu_stride = GEN_SSEU_STRIDE(sseu->max_eus_per_subslice);
 	int ret;
 
 	if (query_item->flags != 0)
@@ -50,7 +49,7 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
 
 	slice_length = sizeof(sseu->slice_mask);
 	subslice_length = sseu->max_slices * sseu->ss_stride;
-	eu_length = sseu->max_slices * sseu->max_subslices * eu_stride;
+	eu_length = sseu->max_slices * sseu->max_subslices * sseu->eu_stride;
 	total_length = sizeof(topo) + slice_length + subslice_length +
 		       eu_length;
 
@@ -70,7 +69,7 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
 	topo.subslice_offset = slice_length;
 	topo.subslice_stride = sseu->ss_stride;
 	topo.eu_offset = slice_length + subslice_length;
-	topo.eu_stride = eu_stride;
+	topo.eu_stride = sseu->eu_stride;
 
 	if (__copy_to_user(u64_to_user_ptr(query_item->data_ptr),
 			   &topo, sizeof(topo)))

drivers/gpu/drm/i915/intel_device_info.c

@@ -118,10 +118,9 @@ void intel_device_info_dump_runtime(const struct intel_runtime_info *info,
 static int sseu_eu_idx(const struct sseu_dev_info *sseu, int slice,
 		       int subslice)
 {
-	int subslice_stride = GEN_SSEU_STRIDE(sseu->max_eus_per_subslice);
-	int slice_stride = sseu->max_subslices * subslice_stride;
+	int slice_stride = sseu->max_subslices * sseu->eu_stride;
 
-	return slice * slice_stride + subslice * subslice_stride;
+	return slice * slice_stride + subslice * sseu->eu_stride;
 }
 
 static u16 sseu_get_eus(const struct sseu_dev_info *sseu, int slice,
@@ -130,7 +129,7 @@ static u16 sseu_get_eus(const struct sseu_dev_info *sseu, int slice,
 	int i, offset = sseu_eu_idx(sseu, slice, subslice);
 	u16 eu_mask = 0;
 
-	for (i = 0; i < GEN_SSEU_STRIDE(sseu->max_eus_per_subslice); i++) {
+	for (i = 0; i < sseu->eu_stride; i++) {
 		eu_mask |= ((u16)sseu->eu_mask[offset + i]) <<
 			(i * BITS_PER_BYTE);
 	}
@@ -143,7 +142,7 @@ static void sseu_set_eus(struct sseu_dev_info *sseu, int slice, int subslice,
 {
 	int i, offset = sseu_eu_idx(sseu, slice, subslice);
 
-	for (i = 0; i < GEN_SSEU_STRIDE(sseu->max_eus_per_subslice); i++) {
+	for (i = 0; i < sseu->eu_stride; i++) {
 		sseu->eu_mask[offset + i] =
 			(eu_mask >> (BITS_PER_BYTE * i)) & 0xff;
 	}