drm/i915/sseu: Disassociate internal subslice mask representation from uapi

As with EU masks, it's easier to store subslice/DSS masks internally in
a format that's more natural for the driver to work with, and then only
covert into the u8[] uapi form when the query ioctl is invoked.  Since
the hardware design changed significantly with Xe_HP, we'll use a union
to choose between the old "hsw-style" subslice masks or the newer xehp
mask.  HSW-style masks will be stored in an array of u8's, indexed by
slice (there's never more than 6 subslices per slice on older
platforms).  For Xe_HP and beyond where slices no longer exist, we only
need a single bitmask.  However we already know that this mask is
eventually going to grow too large for a simple u64 to hold, so we'll
represent it in a manner that can be operated on by the utilities in
linux/bitmap.h.

v2:
 - Fix typo: BIT(s) -> BIT(ss) in gen9_sseu_device_status()

v3:
 - Eliminate sseu->ss_stride and just calculate the stride while
   specifically handling uapi.  (Tvrtko)
 - Use BITMAP_BITS() macro to refer to size of masks rather than
   passing I915_MAX_SS_FUSE_BITS directly.  (Tvrtko)
 - Report compute/geometry DSS masks separately when dumping Xe_HP SSEU
   info.  (Tvrtko)
 - Restore dropped range checks to intel_sseu_has_subslice().  (Tvrtko)

v4:
 - Make the bitmap size macro check the size of the .xehp field rather
   than the containing union.  (Tvrtko)
 - Don't add GEM_BUG_ON() intel_sseu_has_subslice()'s check for whether
   slice or subslice ID exceed sseu->max_[sub]slices; various loops
   in the driver are expected to exceed these, so we should just
   silently return 'false.'

v5:
 - Move XEHP_BITMAP_BITS() to the header so that we can also replace a
   usage of I915_MAX_SS_FUSE_BITS in one of the inline functions.
   (Bala)
 - Change the local variable in intel_slicemask_from_xehp_dssmask() from
   u16 to 'unsigned long' to make it a bit more future-proof.

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220601150725.521468-6-matthew.d.roper@intel.com

1 files changed, 7 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
index 89c475d525b8..0094f67c63f2 100644
--- a/drivers/gpu/drm/i915/i915_query.c
+++ b/drivers/gpu/drm/i915/i915_query.c
@@ -31,10 +31,11 @@ static int copy_query_item(void *query_hdr, size_t query_sz,
 
 static int fill_topology_info(const struct sseu_dev_info *sseu,
 			      struct drm_i915_query_item *query_item,
-			      const u8 *subslice_mask)
+			      intel_sseu_ss_mask_t subslice_mask)
 {
 	struct drm_i915_query_topology_info topo;
 	u32 slice_length, subslice_length, eu_length, total_length;
+	int ss_stride = GEN_SSEU_STRIDE(sseu->max_subslices);
 	int eu_stride = GEN_SSEU_STRIDE(sseu->max_eus_per_subslice);
 	int ret;
 
@@ -44,7 +45,7 @@ static int fill_topology_info(const struct sseu_dev_info *sseu,
 		return -ENODEV;
 
 	slice_length = sizeof(sseu->slice_mask);
-	subslice_length = sseu->max_slices * sseu->ss_stride;
+	subslice_length = sseu->max_slices * ss_stride;
 	eu_length = sseu->max_slices * sseu->max_subslices * eu_stride;
 	total_length = sizeof(topo) + slice_length + subslice_length +
 		       eu_length;
@@ -60,7 +61,7 @@ static int fill_topology_info(const struct sseu_dev_info *sseu,
 	topo.max_eus_per_subslice = sseu->max_eus_per_subslice;
 
 	topo.subslice_offset = slice_length;
-	topo.subslice_stride = sseu->ss_stride;
+	topo.subslice_stride = ss_stride;
 	topo.eu_offset = slice_length + subslice_length;
 	topo.eu_stride = eu_stride;
 
@@ -72,9 +73,9 @@ static int fill_topology_info(const struct sseu_dev_info *sseu,
 			 &sseu->slice_mask, slice_length))
 		return -EFAULT;
 
-	if (copy_to_user(u64_to_user_ptr(query_item->data_ptr +
-					 sizeof(topo) + slice_length),
-			 subslice_mask, subslice_length))
+	if (intel_sseu_copy_ssmask_to_user(u64_to_user_ptr(query_item->data_ptr +
+							   sizeof(topo) + slice_length),
+					   sseu))
 		return -EFAULT;
 
 	if (intel_sseu_copy_eumask_to_user(u64_to_user_ptr(query_item->data_ptr +