[PATCH 06/12] drm/i915: Add function to get subslices

[Stuart Summers]

Add a new function to get a range of subslices for a
given slice.

Signed-off-by: Stuart Summers <stuart.summers at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_sseu.c | 24 ++++++++++++++++++++++++
 drivers/gpu/drm/i915/gt/intel_sseu.h |  2 ++
 2 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.c b/drivers/gpu/drm/i915/gt/intel_sseu.c
index 607c1447287c..b2ca46c5fa8e 100644
--- a/drivers/gpu/drm/i915/gt/intel_sseu.c
+++ b/drivers/gpu/drm/i915/gt/intel_sseu.c
@@ -30,6 +30,30 @@ intel_sseu_subslice_total(const struct sseu_dev_info *sseu)
 	return total;
 }
 
+u32 intel_sseu_get_subslices(const struct sseu_dev_info *sseu, u8 slice)
+{
+	int i, offset = slice * sseu->ss_stride;
+	u32 mask = 0;
+
+	if (slice >= sseu->max_slices) {
+		DRM_ERROR("%s: invalid slice %d, max: %d\n",
+			  __func__, slice, sseu->max_slices);
+		return 0;
+	}
+
+	if (sseu->ss_stride > sizeof(mask)) {
+		DRM_ERROR("%s: invalid subslice stride %d, max: %lu\n",
+			  __func__, sseu->ss_stride, sizeof(mask));
+		return 0;
+	}
+
+	for (i = 0; i < sseu->ss_stride; i++)
+		mask |= (u32)sseu->subslice_mask[offset + i] <<
+			i * BITS_PER_BYTE;
+
+	return mask;
+}
+
 void intel_sseu_set_subslices(struct sseu_dev_info *sseu, int slice,
 			      u32 ss_mask)
 {
diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.h b/drivers/gpu/drm/i915/gt/intel_sseu.h
index 2261d4e7d98b..ddf62558f924 100644
--- a/drivers/gpu/drm/i915/gt/intel_sseu.h
+++ b/drivers/gpu/drm/i915/gt/intel_sseu.h
@@ -75,6 +75,8 @@ intel_sseu_subslice_total(const struct sseu_dev_info *sseu);
 unsigned int
 intel_sseu_subslices_per_slice(const struct sseu_dev_info *sseu, u8 slice);
 
+u32  intel_sseu_get_subslices(const struct sseu_dev_info *sseu, u8 slice);
+
 void intel_sseu_set_subslices(struct sseu_dev_info *sseu, int slice,
 			      u32 ss_mask);
 
-- 
2.21.0.5.gaeb582a983